JP4283222B2 - Gasification furnace and gasification method - Google Patents

Description

  The present invention relates to a gasification furnace that thermally decomposes and gasifies various wastes, solid fuel, and the like.

In a fluidized bed gasification furnace that thermally decomposes and gasifies various wastes and solid fuels, among various factors related to the reaction, for example, to change the temperature of the fluidized bed of the gasification furnace, gasification The flow rate of oxygen supplied into the furnace or the flow rate of a gas containing oxygen (for example, air) has been changed.
However, when the supply of oxygen is increased, the amount of combustion gas contained in the product gas increases and the heat generation amount of the product gas decreases. On the other hand, when the supply of oxygen is reduced, the generation amount of gasification residues such as char and tar increases, and the gasification efficiency decreases.
In order to cope with this, it has a gasification zone that gasifies various wastes and solid fuel, and a combustion zone that burns gasification residues such as char and tar generated by gasification, and combustion generated in the combustion zone Internal circulation that uses heat for gasification reaction heat in the gasification zone, and further uses each of the gasification zone and the combustion zone as a fluidized bed device to transfer the gasification residue and heat through the fluidized medium. There is a method using a fluidized bed gasifier.
In the internal circulation fluidized bed type gasification furnace, the movement of gasification residue from the gasification zone to the combustion zone and the heat transfer from the combustion zone to the gasification zone are performed smoothly. It is important to control. However, in this conventional internally circulating fluidized bed type gasification furnace, in order to control the moving amount of the fluidized medium particles, it is necessary to greatly change the amount of fluidizing gas supplied to the fluidized bed apparatus. There was a problem that the operating conditions changed greatly. Further, there has been a demand for improvement in ease of control, degree of freedom of control, stability characteristics of operation, accuracy of control, width of control, speed of control, and the like.
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an internal circulation fluidized bed type gasifier having greatly improved control characteristics.

In the present invention, for example, as shown in FIG. 1, a high-temperature fluid medium c is flowed inside to form a gasification chamber fluidized bed having a first interface, and an object to be processed a in the gasification chamber fluidized bed. A gasification chamber 1 for gasifying the gas; a high-temperature fluid medium c is flowed inside to form a char combustion chamber fluidized bed having a second interface, and the char h generated by gasification in the gasification chamber 1 is formed. And a char combustion chamber 2 for heating the fluid medium c in the fluidized bed of the char combustion chamber; the gasification chamber 1 and the char combustion chamber 2 are vertically above the interface between the fluidized beds. There are communication ports 21 and 25 that are partitioned by the partition walls 11 and 15 so that there is no gas flow, and the gasification chamber 1 and the char combustion chamber 2 communicate with each other below the partition walls 11 and 15. The height of the upper ends of 21 and 25 is below the first interface and the second interface. Communication ports 21 and 25 are formed, and the fluidized state of the fluid medium c in the vicinity of the communication ports 21 and 25 in one of the gasification chamber 1 and the char combustion chamber 2 sandwiching the communication ports 21 and 25 is the other. The fluid medium c is stronger than the fluidized state of the fluid medium c in the vicinity of the communication ports 21 and 25 of the chamber, and the fluid medium c moves through the communication ports 21 and 25 from the weak fluidized state to the strong fluidized state. Furthermore, by adjusting the strength of the weak fluidized state, the amount of the fluid medium c flowing between the gasification chamber 1 and the char combustion chamber 2 is controlled, and the gasification chamber 1 or 2 includes a control device 6 for controlling the temperature of the char combustion chamber 2;
If comprised in this way, since the gasification chamber 1, the char combustion chamber 2, and the control apparatus 6 are provided, the gasification chamber 1 and the char combustion chamber 2 are adjusted by adjusting the strength of the weak fluidization state. It is possible to control the temperature of the gasification chamber 1 or the char combustion chamber 2 by controlling the amount of the fluid medium c that flows between them. The control device 6 may also adjust the strength of the strong fluidized state. The temperature of the gasification chamber 1 is typically the temperature of the gasification fluidized bed, and the temperature of the char combustion chamber 2 is typically the temperature of the char combustion chamber fluidized bed. In addition, since the strength of the flow in the weak fluidized state is adjusted, the change in the flow rate of the fluidized gases g1, g2, and g4 generated to control the amount of the fluid medium c is small and greatly affects other operating conditions. Without this, the temperature of the gasification chamber 1 or the char combustion chamber 2 can be controlled.
The fluidized bed is typically fluidized by a fluidized gas g blown from the furnace bottom. The fluidization state can be adjusted by the blowing speed and the blowing amount of the fluidizing gas g. It is good to arrange | position the diffuser 31-35 in a furnace bottom, and to divide | segment into several division 1a, 1b, 2a, 2b, 4a. You may provide the control valves 61-65 which adjust the flow volume of fluidizing gas g1, g2, g4 for every division which wants to adjust the quantity of fluidizing gas g1, g2, g4. By adjusting the opening degree of the control valves 61 to 65 of the respective compartments 1a, 1b, 2a, 2b, and 4a of the gasification chamber 1 and the char combustion chamber 2 across the communication ports 21 and 25, fluidization is achieved. The fluidization state can be adjusted by adjusting the blowing speed and amount of the gas g1, g2, g4.
For example, as shown in FIG. 1, the gasification furnace 101 includes a gasification chamber 1 that thermally decomposes an object to be processed a with a high-temperature fluid medium c to generate gas b and char h; A char combustion chamber 2 for burning the char h and heating the fluid medium c; the fluid medium c is configured to circulate between the gasification chamber 1 and the char combustion chamber 2; A control device 6 that controls the composition of the gas b generated in the gasification chamber 1 by adjusting the circulation amount of the gas may be provided.
If comprised in this way, since the gasification chamber 1, the char combustion chamber 2, and the control apparatus 6 are provided, the composition of the gas b generated in the gasification chamber 1 is adjusted by adjusting the circulation amount of the fluid medium c. Can be controlled. The control device 6 may control the concentration of one kind of gas, or may control the concentration ratio of a plurality of gases to a predetermined set value.
For example, as shown in FIG. 1, the gasification furnace 101 causes a high-temperature fluid medium c to flow inside to form a gasification chamber fluidized bed having a first interface, and to be treated in the gasification chamber fluidized bed. A gasification chamber 1 for gasifying the substance a; a high-temperature fluid medium c is flowed inside to form a char combustion chamber fluidized bed having a second interface, and is generated along with gasification in the gasification chamber 1 A char combustion chamber 2 for burning the char h in the char combustion chamber fluidized bed and heating the fluid medium c; the gasification chamber 1 and the char combustion chamber 2 are vertically above the interface between the fluidized beds. Are divided by partition walls 11 and 15 so that there is no gas flow, and communication ports 21 and 25 communicating the gasification chamber 1 and the char combustion chamber 2 at the lower part of the partition walls 11 and 15, The heights of the upper ends of the communication ports 21 and 25 are the first interface and the second boundary. The following communication ports 21 and 25 are formed, and the fluidized state of the fluid medium c in the vicinity of the communication ports 21 and 25 in one of the gasification chamber 1 and the char combustion chamber 2 sandwiching the communication ports 21 and 25 is The fluid medium c is stronger than the fluidized state of the fluid medium c in the vicinity of the communication ports 21 and 25 of the other chamber, and the fluid medium c passes through the communication ports 21 and 25 from the weak fluidized state to the stronger fluidized state. The gas flow is controlled by controlling the amount of the flow medium c flowing between the gasification chamber 1 and the char combustion chamber 2 by adjusting the strength of the flow in the weak fluidized state. A control device 6 that controls the composition of the gas b generated by the conversion may be provided.
If comprised in this way, since the gasification chamber 1, the char combustion chamber 2, and the control apparatus 6 are provided, the gasification chamber 1 and the char combustion chamber 2 are adjusted by adjusting the strength of the weak fluidization state. The composition of the gas b generated by gasification can be controlled by controlling the amount of the fluid medium c flowing between them. In addition, since the strength of the flow in the weak fluidized state is adjusted, the change in the flow rate of the fluidized gases g1, g2, and g4 generated to control the amount of the fluid medium c is small and greatly affects other operating conditions. The composition of the gas b generated from the gasification chamber 1 can be controlled without any problems.
For example, as shown in FIG. 1, the gasification furnace 101 is a heat recovery chamber 3 that further introduces a fluid medium c from the char combustion chamber 2, and heat that recovers heat from the fluid medium c from the char combustion chamber 2. A heat recovery chamber 3 having a recovery device 41; and a control device 6 that controls the amount of heat recovery in the heat recovery device 41 by adjusting the strength of the flow in the heat recovery chamber 3 may be provided.
If comprised in this way, since the heat recovery chamber 3 which has the heat recovery apparatus 41 and the control apparatus 6 are provided, by adjusting the strength of the flow in the heat recovery chamber 3 by the control apparatus 6, in the heat recovery apparatus 41 The amount of heat recovery can be controlled. The heat recovery chamber 3 is typically a heat recovery chamber 3 provided adjacent to the char combustion chamber 2. The heat recovery device 41 is typically configured to include an in-layer heat transfer tube 41. The heat recovery device 41 typically superheats the steam s1 with the recovered heat. The control device 6 may control the amount of steam s1 that is superheated.
When the gasification furnace 101 includes the heat recovery chamber 3 provided in contact with the char combustion chamber 2, the fluidized bed portion of the char combustion chamber fluidized bed is provided between the char combustion chamber 2 and the heat recovery chamber 3. A partition wall 12 is provided. An opening 22 is formed in the lower part of the partition wall 12, and the fluid medium c in the char combustion chamber 2 flows into the heat recovery chamber 3 from the upper part of the partition wall 12, and the char is passed through the opening 22. It is good to comprise so that the circulation flow which returns to the combustion chamber 2 may be formed.
In the gasification furnace 101, for example, as shown in FIG. 1, the control device 6 that further controls the heat recovery amount controls the heat recovery amount in the heat recovery device 41 and controls the temperature of the char combustion chamber 2. There may be.
For example, as shown in FIG. 1, the gasification furnace 101 further includes a first pressure above the first interface of the gasification chamber 1 and a second pressure above the second interface of the char combustion chamber 2. Pressure measuring devices 81 and 82 for measuring the gas b generated from the gasification chamber 1, the first discharge linear velocity discharged from the gasification chamber 1, and the combustion gas e generated from the char combustion chamber 2. Adjusting devices 78 and 79 for adjusting the second discharge linear velocity discharged from the char combustion chamber 2; and an adjusting device 78 so that the pressure difference between the first pressure and the second pressure is a predetermined value. , 79 may be provided.
If comprised in this way, since the pressure measuring devices 81 and 82, the adjusting devices 78 and 79, and the control device 6 are provided, the pressure measuring devices 81 and 82 measure the first pressure and the second pressure, The first discharge linear velocity and the second discharge linear velocity are adjusted by the adjusting devices 78 and 79, and the pressure difference between the first pressure and the second pressure is set to a predetermined value by the control device 6. The adjusting devices 78 and 79 can be controlled.
Since the pressure difference between the first pressure and the second pressure can be set to a predetermined value, the influence of the pressure on the moving amount of the fluid medium particles between the gasification chamber 1 and the char combustion chamber 2 is constant. Therefore, it is easy to precisely control the moving amount of the fluid medium particles. The predetermined value may be substantially equal to zero, or the control device 6 may control the adjusting devices 78 and 79 so that the first pressure and the second pressure are substantially equal.
This application is based on Japanese Patent Application No. 2002-236997 filed on August 15, 2002 in Japan, the contents of which form part of the present application.
The present invention will also be more fully understood from the following detailed description. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, the detailed description and specific examples are the preferred embodiments of the present invention and are provided for illustrative purposes only. From this detailed description, various changes and modifications will be apparent to those skilled in the art within the spirit of the invention.
The applicant does not intend to contribute any of the described embodiments to the public, and the disclosed modifications and alternatives that may not be included in the scope of the claims are equivalent. It is part of the invention under discussion.

FIG. 1 is a block diagram conceptually showing the structure of an integrated gasifier.
FIG. 2 is a schematic side cross-sectional view of two chambers partitioned by a partition wall. It is classified into (a), (b), and (c) according to the form of the partition wall.
FIG. 3 is a diagram showing the relationship between the fluidized gas velocity and the apparent layer viscosity.
FIG. 4 is a diagram showing the relationship between the fluidizing gas velocity and the amount of movement of the fluid medium.
FIG. 5 is a block diagram in the case where a predetermined weak fluidization region and a strong fluidization region are separated into a region near a predetermined opening and a remote region.
FIG. 6 is a view for explaining the definition of the circulation amount of the fluid medium circulating between the gasification chamber and the sedimentation char combustion chamber.
FIG. 7 is a view for explaining diffusion of the fluidized medium between the gasification chamber and the settled char combustion chamber.
FIG. 8 is a diagram showing the relationship between the superficial velocity of the fluidized gas in the settling char combustion chamber, the amount of heat transfer from the settling char combustion chamber to the gasification chamber, and the amount of circulation (convection).
FIG. 9 is a diagram showing the relationship between the superficial velocity of the fluidized gas in the settling char combustion chamber and the amount of movement of the fluid medium (convection + diffusion) from the settling char combustion chamber to the gasification chamber.
FIG. 10 is a diagram for explaining the relationship between the fluidized bed height and the circulation rate.
FIG. 11 is a diagram showing the relationship between the circulation ratio and the gasification chamber layer temperature in case 1.
FIG. 12 is a diagram showing the relationship between the circulation ratio and the gasification chamber layer temperature in case 2.
FIG. 13 is a diagram showing the relationship between the circulation ratio and the product gas composition.
FIG. 14 is a diagram showing the relationship between the circulation ratio and the H ₂ / CO ratio of the product gas.
FIG. 15 is a diagram showing a relationship between the circulation ratio and the generated gas heat generation amount.
FIG. 16 is a diagram showing the relationship between the gasification chamber layer temperature and the gasification chamber outlet heat rate.
FIG. 17 is a diagram showing the relationship between the gasification chamber layer temperature and the cold gas efficiency.
FIG. 18 is a diagram showing the relationship between the circulation ratio and the generated gas heat generation amount.
FIG. 19 is a diagram showing the relationship between the gasification chamber layer temperature and the ratio of carbon in the raw material to tar.
FIG. 20 is a diagram showing the relationship between the circulation rate and the rate at which carbon in the raw material moves to the char combustion chamber.
FIG. 21 is a diagram showing the relationship between the gasification chamber layer temperature and the rate at which carbon in the raw material moves to the char combustion chamber.
FIG. 22 is a block diagram illustrating a configuration of the fluid medium supply device.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram conceptually showing the configuration of an integrated gasification furnace 101 as a gasification furnace.
The integrated gasification furnace 101 includes a gasification chamber 1 that thermally decomposes and gasifies waste or solid fuel a as an object to be processed, and a char combustion chamber 2 that burns the char fraction h generated in the gasification chamber 1. A gas utilization device (in the latter stage of the integrated gasification furnace 101) that includes the product gas b as a combustible gas generated in the gasification chamber 1 and the combustion gas e generated in the char combustion chamber 2. (Not shown) and supplied separately. The char combustion chamber 2 includes a char combustion chamber main body 5 and a sedimentation char combustion chamber (fluid medium sedimentation chamber) 4. The integrated gasification furnace 101 is connected to the gasification chamber 1 and is connected to the char combustion chamber main body 5 and the generated gas supply pipe 26 for supplying the generated gas b generated in the gasification chamber 1 and the char combustion chamber main body 5. And a combustion gas supply pipe 27 for supplying the combustion gas e generated in the above. The integrated gasification furnace 101 further includes a gas composition measuring device 46 that is installed in the product gas supply pipe 26 and measures the gas composition of the product gas b.
The integrated gasification furnace 101 is installed in the product gas supply pipe 26 and is a control valve as an adjustment device that adjusts the discharge linear velocity (first exhaust linear velocity) of the product gas b exhausted from the product gas supply piping 26. 78 (for example, a damper) and a control valve as an adjusting device that is installed in the combustion gas supply pipe 27 and adjusts the discharge linear velocity (second exhaust linear velocity) of the combustion gas e exhausted from the combustion gas supply piping 27 79 (for example, a damper).
The integrated gasification furnace 101 includes a heat recovery chamber 3 in charge of a heat recovery function in addition to the gasification chamber 1 and char combustion chamber 2 in charge of the above-described pyrolysis gasification and char combustion functions, respectively. The gasification chamber 1, the char combustion chamber 2, and the heat recovery chamber 3 are accommodated in a furnace body that is entirely cylindrical or rectangular, for example. The integrated gasification furnace 101 includes a control device 6 that controls control valves 61, 62, 63, 64, 65, 66, and 67 (61 to 67) described later. The control device 6 also controls the control valves 78 and 79 described above. The gasification chamber 1, the char combustion chamber 2, and the heat recovery chamber 3 are divided by partition walls 11 to 15, and a fluidized bed that is a dense layer containing a high-temperature fluidized medium c is formed at the bottom of each.
The gasification chamber 1 and the char combustion chamber main body 5 are provided with temperature measuring devices 42 and 43 for measuring the layer temperatures of the respective thick layers. In the present embodiment, the layer temperature of the rich layer in the gasification chamber 1 is the temperature of the gasification chamber 1, and the layer temperature of the rich layer in the char combustion chamber body 5 is the temperature of the char combustion chamber 2. . The temperature measuring devices 42 and 43 send to the control device 6 a temperature signal i3 (partially indicated by a broken line in the figure) based on the measured temperature. As will be described later, the control device 6 may be configured to control the control valves 61 to 67 so that the temperature of the temperature char combustion chamber 2 of the gasification chamber 1 becomes a set value based on the temperature signal i3. In this case, the control device 6 is the control device for controlling the temperature of the present invention. Further, the gas composition measuring device 46 described above sends a gas composition signal i4 based on the measured gas composition to the control device 6. As will be described later, the control device 6 can be configured to control the control valves 61 to 67 so that the gas composition of the generated gas b becomes a set value based on the gas composition signal i4. The apparatus 6 is a control apparatus for controlling the gas composition of the present invention. The temperature measuring devices 42 and 43 use thermocouples.
The gasification chamber 1 and the char combustion chamber main body 5 are provided with pressure measuring devices 81 and 82 for measuring the pressures of the respective free board portions. The pressure of the free board part of the gasification chamber 1 is the first pressure of the present invention, and the pressure of the free board part of the char combustion chamber main body part 5 is the second pressure of the present invention. The free board unit will be described later. The pressure measuring devices 81 and 82 send a pressure signal i5 (partially indicated by a broken line in the drawing) to the control device 6 based on the measured pressure. The control device 6 can be configured to control the control valves 61 to 67 so that the pressure in the gasification chamber 1 and the pressure in the char combustion chamber 2 are set to predetermined values based on the pressure signal i5.
The gas composition signal i4 is H ₂ , CO, CO ₂ , CH ₄ , H ₂ It is good to set it as mol%, such as O. The control device 6 obtains the gas composition signal i4, and H ₂ / CO ratio etc. is calculated, and further generated by the gas composition signal i4, the temperature signal i3 of the product gas b measured by the temperature measuring device 42, and the pressure signal i5 of the product gas b measured by the pressure measuring device 81 The calorific value of the gas b may be calculated.
In order to flow the fluidized media c in the fluidized beds of the chambers 1 to 3, that is, the gasification chamber fluidized bed, the char combustion chamber fluidized bed, and the heat recovery chamber fluidized bed, The fluidized gas g1, g2, g3, and g4 (discrimination of fluidized gases g1, g2, g3, and g4 will be described later; hereinafter, the fluidized gas is collectively referred to as “g”) is blown into the fluidized medium c. Air devices 31-36 are provided. That is, the gasification chamber 1 is provided with air diffusers 31, 32, the char combustion chamber 2 is provided with air diffusers 33, 34, 35, and the heat recovery device 3 is provided with an air diffuser 36. Each of the air diffusers 31 to 36 includes, for example, a perforated plate laid on the bottom of the furnace where the air diffusers 31 to 36 are installed, and the perforated plates are divided in a width direction into a plurality of rooms. It is divided.
The integrated gasification furnace 101 is connected to a supply pipe 51 connected to the diffuser 31, a supply pipe 52 connected to the diffuser 32, a supply pipe 53 connected to the diffuser 33, and the diffuser 34. The supply pipe 54, the supply pipe 55 connected to the air diffuser 35, and the supply pipe 56 connected to the air diffuser 36 are provided. The supply pipes 51 to 56 include control valves 61 to 66 as flow control devices and flow rate measuring devices 71 to 76, respectively, and supply the fluidized gas g to the air diffusers 31 to 36. The control valves 61-66 adjust the supply amount of the fluidized gas g to the air diffusers 31-36. Therefore, each of the air diffusers 31 to 36 is provided in each part in each of the chambers 1 to 3 (in the figure, the locations indicated by 1a and 1b of the chamber 1, the locations indicated by 2a, 2b and 4a of the chamber 2, and the 3a of the chamber 3 In order to change the superficial velocity at the location (shown), the flow velocity of the fluidized gas g blown out from each room of the diffusers 31 to 36 through the perforated plate is changed. The flow rate measuring devices 71 to 76 are installed on the downstream side of the control valves 61 to 66 of the supply pipes 51 to 56, and measure the flow rate of the fluidized gas g. The control valves 61 to 66 are operated in response to different control signals i1 (partially indicated by broken lines in the drawing) sent from the control device 6 to change the opening degree. The flow rate measuring devices 71 to 76 send a flow rate signal i2 (partially indicated by a broken line in the drawing) to the control device 6 based on the measured flow rate.
Moreover, since the superficial velocity is relatively different in each part of the chambers 1 to 3, the fluidized medium c in each of the chambers 1 to 3 is also in a different fluidized state in each part of the chambers 1 to 3, so that an internal swirl flow is formed. The Moreover, since the fluidization state differs in each part of the chambers 1 to 3, the internal swirl circulates through the chambers 1 to 3 in the furnace. In the figure, the size of the white arrow shown in the air diffusers 31 to 36 indicates the flow velocity of the fluidized gas g to be blown out. For example, the thick arrow at the location indicated by 2b has a higher flow velocity than the thin arrow at the location indicated by 2a. Further, the flow velocity at the location indicated by the white arrow is uniform throughout the location.
The gasification chamber 1 and the char combustion chamber body 5 are partitioned by a partition wall 11 and a partition wall 15, and the char combustion chamber body 5 and the heat recovery chamber 3 are partitioned by a partition wall 12. And the heat recovery chamber 3 are partitioned by a partition wall 13 (note that since this figure shows the furnace expanded in a plane, the partition wall 11 includes the gasification chamber 1 and the char combustion chamber main body. The partition wall 13 is shown as if not between the gasification chamber 1 and the heat recovery chamber 3). That is, in the integrated gasification furnace 101, each of the first to third chambers is not configured as a separate furnace, but is configured integrally as one furnace. Further, a settling char combustion chamber 4 is provided in the vicinity of the surface of the char combustion chamber main body 5 in contact with the gasification chamber 1 so that the fluid medium c descends. That is, as described above, the char combustion chamber 2 is divided into the settling char combustion chamber 4 and the char combustion chamber main body 5 other than the settling char combustion chamber 4. Therefore, a partition wall 14 is provided for partitioning the settled char combustion chamber 4 from the other portion of the char combustion chamber 2 (the char combustion chamber main body 5). The sedimentation char combustion chamber 4 and the gasification chamber 1 are partitioned by a partition wall 15 as shown in FIG.
Here, the fluidized bed and the interface will be described. The fluidized bed is located in a vertically lower portion of the fluidized bed, and a dense layer containing the fluidized medium c (for example, silica sand) in a fluidized state by the fluidized gas g, and a vertically upper portion of the dense layer. It consists of a splash zone in which a large amount of gas coexists with the fluid medium c, and the fluid medium c repels vigorously. Above the fluidized bed, that is, above the splash zone, there is a free board portion that contains almost no fluid medium c and is mainly gas. The interface refers to the splash zone having a certain thickness, but may also be considered as a virtual surface intermediate between the upper surface and the lower surface of the splash zone (the upper surface of the dense layer).
In addition, when “partitioned by a partition wall so that there is no gas flow in the vertical direction above the fluidized bed interface”, there is no gas flow in the vertical direction above the upper surface of the dense layer vertically below the interface. Is preferable.
The partition wall 11 between the gasification chamber 1 and the char combustion chamber main body 5 is partitioned almost entirely from the ceiling 19 of the furnace to the bottom of the furnace (the perforated plate of the air diffuser 31). There is no contact with the bottom, and there is an opening 21 as a communication port near the bottom of the furnace. However, the upper end of the opening 21 does not reach the upper part of any of the gasification chamber fluidized bed interface as the first interface and the char combustion chamber fluidized bed interface as the second interface. More preferably, the upper end of the opening 21 does not reach the upper part of either the upper surface of the rich layer of the gasification chamber fluidized bed or the upper surface of the rich layer of the char combustion chamber fluidized bed. In other words, the opening 21 is preferably configured so as to be always hidden in the thick layer. That is, the gasification chamber 1 and the char combustion chamber 2 are separated by partition walls so that there is no gas flow at least in the freeboard portion, more specifically above the interface, and more preferably above the upper surface of the dense layer. It will be partitioned.
The partition wall 12 between the char combustion chamber 2 and the heat recovery chamber 3 has an upper end near the interface, that is, above the upper surface of the dense layer, but below the upper surface of the splash zone. The lower end of 12 extends to the vicinity of the furnace bottom, and the lower end does not contact the furnace bottom as in the partition wall 11, and there is an opening 22 in the vicinity of the furnace bottom that does not reach above the upper surface of the thick layer. In other words, only the fluidized bed portion is partitioned between the char combustion chamber 2 and the heat recovery chamber 3 by the partition wall 12, the opening 22 is provided in the vicinity of the hearth surface of the partition wall 12, and the char combustion chamber 2 The fluid medium c flows from the upper part of the partition wall 12 into the heat recovery chamber 3 and has a circulation flow that returns to the char combustion chamber 2 again through the opening 22 near the hearth surface of the partition wall 12.
The partition wall 13 between the gasification chamber 1 and the heat recovery chamber 3 is completely partitioned from the furnace bottom to the furnace ceiling. The upper end of the partition wall 14 that partitions the char combustion chamber 2 to provide the sedimentation char combustion chamber 4 is in the vicinity of the interface of the fluidized bed, and the lower end is in contact with the furnace bottom. The relationship between the upper end of the partition wall 14 and the fluidized bed is the same as the relationship between the partition wall 12 and the fluidized bed. The partition wall 15 that partitions the settling char combustion chamber 4 and the gasification chamber 1 is the same as the partition wall 11 and is partitioned almost entirely from the ceiling of the furnace to the bottom of the furnace, and the lower end is in contact with the bottom of the furnace. There is an opening 25 as a communication port in the vicinity of the furnace bottom, and the upper end of this opening is below the upper surface of the thick layer. That is, the relationship between the opening 25 and the fluidized bed is the same as the relationship between the opening 21 and the fluidized bed.
The waste or solid fuel a put into the gasification chamber 1 receives heat from the fluid medium c, and is pyrolyzed and gasified to produce a product gas b. Typically, the waste or fuel a does not burn in the gasification chamber 1, but is so-called dry distillation. The remaining dry distillation char h flows into the char combustion chamber main body 5 from the opening 21 at the lower part of the partition wall 11 together with the fluid medium c. The char h introduced from the gasification chamber 1 in this way is combusted in the char combustion chamber main body 5 and heats the fluid medium c. The fluid medium c heated by the combustion heat of the char h in the char combustion chamber main body 5 passes over the upper end of the partition wall 12 and flows into the heat recovery chamber 3 so that it is below the interface in the heat recovery chamber 3. After the heat is collected and cooled by the in-layer heat transfer tube 41 as a heat recovery device arranged, it flows into the char combustion chamber main body 5 again through the opening 22 at the lower part of the partition wall 12.
The in-layer heat transfer tube 41 includes an in-layer heat transfer tube main body 41A disposed in the heat recovery chamber 3, an introduction portion 41B for introducing the steam s1 to the in-layer heat transfer tube main body 41A, and the superheated steam s2 from the in-layer heat transfer tube main body 41A. It consists of the discharge part 41C which discharges. The steam s1 introduced into the in-layer heat transfer tube main body 41A is superheated to become superheated steam s2.
The integrated gasification furnace 101 includes temperature measuring devices 44 and 45, a control valve 67, and a flow rate measuring device 77. The temperature measuring device 44 is installed in the introduction part 41B and measures the temperature of the steam s1. The regulating valve 67 is installed in the introduction part 41B and controls the flow rate of the steam s1. The flow rate measuring device 77 is installed in the introduction part 41B and measures the flow rate of the steam s1. The temperature measuring device 45 is installed in the discharge unit 41C and measures the temperature of the superheated steam s2. The control valve 67 operates in response to a control signal i1 (partially indicated by a broken line in the drawing) sent from the control device 6 to change the opening degree. The flow rate measuring device 77 sends a flow rate signal i2 (partially indicated by a broken line in the figure) based on the measured flow rate to the control device 6, and the temperature measuring devices 44 and 45 are temperature signals i3 based on the measured temperature. (Partially indicated by broken lines in the figure) is sent to the control device 6. The control device 6 is a control device that controls the heat recovery amount of the present invention.
Here, the heat recovery chamber 3 is not essential in the integrated gasification furnace 101 according to the embodiment of the present invention. That is, if the amount of char h mainly composed of carbon remaining after gasification of the volatile component in the gasification chamber 1 is substantially equal to the amount of char required for heating the fluid medium c in the char combustion chamber 2. The heat recovery chamber 3 that takes heat away from the fluid medium c is not necessary. If the difference in the amount of char h is small, for example, the gasification temperature in the gasification chamber 1 becomes high, and the balance state is maintained in the form that the amount of CO gas generated in the gasification chamber 1 increases. Be drunk.
However, when the heat recovery chamber 3 is provided as shown in FIG. 1, it is possible to deal with a wide variety of wastes or fuels a, ranging from coal with a large amount of char h to municipal waste that hardly generates char h. it can. That is, for any waste or fuel a, by adjusting the amount of heat recovered in the heat recovery chamber 3, the combustion temperature of the char combustion chamber main body 5 is adjusted appropriately, and the temperature of the fluid medium c is adjusted. Can be kept appropriate. Further, the amount of fluidized gas g3 supplied to the diffuser 36 is adjusted by a control valve 66, and the strength of the fluidized state in the heat recovery chamber 3 having the weak fluidized region 3a maintained in a weak fluidized state is adjusted. By adjusting, the heat recovery amount in the heat recovery chamber 3 can be controlled. Therefore, the control device 6 that controls the heat recovery amount controls the heat recovery amount in the in-layer heat transfer tube 41 and controls the temperature of the char combustion chamber 2.
On the other hand, the fluid medium c heated in the char combustion chamber body 5 passes over the upper end of the partition wall 14 and flows into the settled char combustion chamber 4, and then flows into the gasification chamber 1 from the opening 25 at the lower part of the partition wall 15. To do.
Here, referring to the schematic side cross-sectional views of FIGS. 2A, 2B, and 2C, the partition wall X, the partition wall Y, or the partition wall Z formed in the furnace F are separated. The fluidized state and movement of the fluid medium c between the two chambers Ra and Rb will be described. In FIG. 2A, the two chambers Ra and Rb are partitioned by a partition wall X having an opening Px only at the top. In FIG. 2B, the two chambers Ra and Rb are partitioned by a partition wall Y having an opening Qy only at the lower part. In FIG. 2C, the two chambers Ra and Rb are partitioned by a partition wall Z having an opening Pz in the upper part and an opening Qz in the lower part. 2 (a), 2 (b), and 2 (c), air diffusers Da and Db for blowing fluidized gases ga and gb are respectively placed in the furnace bottoms of the chambers Ra and Rb that store the fluid medium c. , Provided. In addition, the upper ends of the partition walls X and Z are in the vicinity of the height of the interface, and the openings Qy and Qz are in positions that are submerged in the thick layer. 2A, 2B, and 2C, the fluidized state in the chamber Ra is uniform in the chamber Ra, and the fluidized state in the chamber Rb is uniform in the chamber Rb. And
Since the movement of the fluid medium c between the two chambers Ra and Rb partitioned by the partition wall X, the partition wall Y, or the partition wall Z is caused by the difference in strength between the fluidization states of the chamber Ra side and the chamber Rb side, The amount of movement and movement of the fluid medium c through the openings Px, Qy, Pz, Qz between the chamber Ra and the chamber Rb can be changed practically by arbitrarily changing the difference in strength between the Ra side and the chamber Rb side. The direction (from chamber Ra to chamber Rb or from chamber Rb to chamber Ra) can be adjusted. Below, it demonstrates concretely how the movement amount of the fluid medium c between the chamber Ra and the chamber Rb can be adjusted when the fluidization state of the chamber Ra and the chamber Rb is changed.
The movement of the fluid medium c between the chamber Ra and the chamber Rb, which moves through the openings Qy and Qz, generally depends on the fluidization state in the vicinity of the openings Ra and Qz on the chamber Ra side and the chamber Rb side. The fluid medium c moves from a weakly fluidized chamber to a strongly fluidized chamber due to the difference in strength between fluidized states in the vicinity of the openings Qy and Qz. 2A, 2B, and 2C, the fluidized state in the chamber Ra is uniform in the chamber Ra, and the fluidized state in the chamber Rb is uniform in the chamber Rb. This can be discussed by the difference in gas velocity between the fluidized gases ga and gb in Ra and the chamber Rb. The fluid medium c moves from the chamber having the lower gas velocity to the chamber having the higher gas velocity.
First, the case where the two chambers Ra and Rb are partitioned by a partition wall X whose upper end is in the vicinity of the height of the interface will be described with reference to FIG. When the fluidization states of the two chambers Ra and Rb are equal, the amount of the flow medium c splashed from the chamber Ra side moves over the partition wall X to the chamber Rb side, and the flow splashed from the chamber Rb side The amount by which the medium c moves over the partition wall X toward the chamber Ra becomes equal on average. Therefore, although the movement of the fluid medium c between the two chambers Ra and Rb occurs locally, the movement amount of the fluid medium c is 0 as a whole (the whole of the chamber Ra and the chamber Rb, respectively). Become.
For example, when the fluidization state of the chamber Ra is made stronger than the fluidization state of the chamber Rb while the fluidization state of the chamber Rb is kept constant, that is, the chamber Ra is kept constant while the fluidization gas velocity of the chamber Rb is kept constant. When the fluidizing gas velocity of the chamber Rb is larger than the fluidizing gas velocity of the chamber Rb, the amount of the fluid medium c splashed from the chamber Ra side moves from the chamber Rb side beyond the partition wall X to the chamber Rb side. Since the amount of the fluid medium c that has been splashed moves beyond the partition wall X toward the chamber Ra increases, the total amount of fluid medium c that moves from the chamber Ra side to the chamber Rb side does not become zero. Then, the fluid medium c moves from the chamber Ra side to the chamber Rb side (this state is indicated by a white arrow in the figure).
Although the case where the fluidizing gas velocity in the chamber Ra is changed to be increased while the fluidizing gas velocity in the chamber Rb is kept constant is considered here, conversely, the fluidizing gas velocity in the chamber Ra is kept constant. Even if the fluidizing gas velocity in the chamber Rb is changed so as to decrease, the same effect can be obtained.
Assuming that the fluid medium c is not replenished or extracted from the outside in the chamber Ra and the chamber Rb, the fluidized bed of the chamber Ra is moved by the movement of the fluid medium c from the chamber Ra side to the chamber Rb side. The height gradually decreases, and the fluidized bed height of the chamber Rb gradually increases.
Since the amount of the fluid medium c that moves from the chamber Ra side to the chamber Rb side beyond the splash partition wall X decreases as the fluidized bed interface on the chamber Ra side decreases, the fluidized bed height of the chamber Ra described above decreases. Thus, the moving amount of the fluid medium c from the chamber Ra side to the chamber Rb side decreases. Similarly, the amount of the fluid medium c in which splashing from the chamber Rb side moves to the chamber Ra side beyond the partition wall X increases as the fluidized bed interface on the chamber Rb side becomes higher. As the bed height increases, the amount of movement of the fluid medium c from the chamber Rb side to the chamber Ra side increases.
For this reason, assuming that the gas velocities of the fluidizing gases ga and gb in the chamber Ra and the chamber Rb are the same, a certain amount is set so that the fluidizing gas velocity in the chamber Ra is larger than the fluidizing gas velocity in the chamber Rb. When the difference is given, initially, the entire fluid medium c moves from the chamber Ra side to the chamber Rb side, but the fluidized bed height of the chamber Ra decreases to some extent, and the fluidized bed height of the chamber Rb increases. In the stage, the amount of movement of the local fluid medium c from the chamber Ra side to the chamber Rb side again and the amount of movement of the local fluid medium c from the chamber Rb side to the chamber Ra side as a whole are balanced. The total movement amount of the fluid medium c between Ra and Rb becomes 0 again.
Therefore, when a certain amount of difference is given so that the fluidizing gas velocity in the chamber Ra is larger than the fluidizing gas velocity in the chamber Rb, the fluid medium c is continuously moved from the chamber Ra to the chamber Rb. For this purpose, the fluid medium c is supplied from the outside to the chamber Ra and flows from the chamber Rb to the outside so that the amount of the fluid medium c filled in both the chambers Ra and Rb, that is, the fluidized bed height is constant. A configuration in which the medium c is extracted is sufficient.
In this case, the larger the difference between the fluidizing gas velocities of the chamber Ra and the chamber Rb, the larger the amount of movement of the fluid medium c from the chamber Ra to the chamber Rb, so that the fluidization of the chamber Rb is stopped. Alternatively, a state close to the minimum fluidization, that is, preferably the fluidization rate is 2 Umf or less, more preferably 1 Umf or less, and the fluidization rate of the chamber Ra is sufficiently higher than this, preferably the fluidization rate is 4 Umf. As described above, more preferably, the maximum moving amount of the fluid medium c can be secured when it is maintained at 5 Umf or more. Here, Umf is a unit in which the minimum fluidization speed (fluidization gas speed at which fluidization is started) is 1 Umf. That is, 5 Umf is 5 times the minimum fluidization speed.
Next, as shown in FIG. 2B, consider a case where the two chambers Ra and Rb are partitioned by a partition wall Y having an opening Qy that is submerged in a thick layer. When the fluidization states of the two chambers Ra and Rb are equal (when the fluidization gas velocity in the chamber Ra is equal to the fluidization gas velocity in the chamber Rb), the chamber Ra side to the chamber Rb side through the opening Qy Although the amount of diffusion of the fluid medium c from the chamber Ra side to the chamber Rb side is balanced, the movement of the fluid medium c between the two chambers Ra and Rb occurs locally, but the overall fluid medium c The amount of movement is zero.
When the fluidization state of the chamber Ra is made stronger than the fluidization state of the chamber Rb while the fluidization state of the chamber Rb is kept the same, that is, the flow of the chamber Ra while keeping the fluidization gas velocity of the chamber Rb constant. When the gasification gas velocity is higher than the fluidization gas velocity in the chamber Rb, a larger amount of bubbles are generated in the dense layer of the chamber Ra than in the dense layer of the chamber Rb. The chamber Rb is lower than the apparent layer density. For this reason, if the fluidized bed heights of the chamber Ra and the chamber Rb are equal, the pressure in the vicinity of the opening Qy at the lower layer of the chamber Ra becomes lower than the pressure in the vicinity of the opening Qy at the lower layer of the chamber Rb. Due to the attracting action using the pressure difference as a driving force, the fluid medium c moves from the chamber Rb side to the chamber Ra side over the entire opening Qy (this state is indicated by a white arrow in the figure). ).
Conversely, when the fluidizing gas velocity in the chamber Rb is reduced while the fluidizing gas velocity in the chamber Ra is kept constant, the situation is slightly different. The movement of the fluid medium c considered here occurs through the opening Qy of the partition wall Y provided in the dense layer, and the pressure difference in the vicinity of the opening Qy at the lower layer of the chamber Ra and the chamber Rb is reduced. This is the driving force. In other words, the pressure difference in the vicinity of the opening Qy at the lower layer of the chamber Ra and the chamber Rb is balanced with the resistance force required for the fluid medium c to move through the opening Qy. The resistance force is closely related to the apparent layer viscosity of the particle layer.
Next, a description will be given with reference to FIGS. 2B, 3 and 4. FIG.
FIG. 3 shows the relationship between the fluidized state of the fluid medium c and the apparent layer viscosity of the particle layer. The gas velocity of the fluidizing gas gb in the chamber Rb is changed in the range shown in FIG. 3, while the gas velocity of the fluidizing gas ga in the chamber Ra is kept constant. In the case of a simple bubbling fluidized bed (no settling flow), the fluidized bed viscosity is almost equal to infinity in a fixed bed with a fluidizing gas velocity of 1 Umf or less. When the fluidizing gas velocity is 1 Umf or more, the viscosity of the fluidized bed decreases rapidly. In the case of the chamber Rb (sedimentation chamber), the relative velocity of the flowing fluid medium and the rising fluidized gas is generated, so that even if the fluidized gas velocity is 1 Umf or less, the fluidized gas relative velocity is 1 Umf or more. Therefore, the viscosity changes and the movement amount (circulation amount) can be controlled. Therefore, the change amount of the fluidized gas amount for controlling the moving amount (circulating amount) of the fluid medium c can be minimized. That is, it is possible to minimize the influence of changes in the process factor (here, the amount of fluidized gas) for controlling the circulation rate on other process factors.
Therefore, when the fluidizing gas velocity in the chamber Rb is reduced while the fluidizing gas velocity in the chamber Ra is kept constant, the movement amount of the fluid medium c is changed in accordance with the absolute value of the fluidizing gas velocity in the chamber Rb. The behavior is different. Assume that in the initial state, both the chamber Ra and the chamber Rb are sufficiently strong fluidized, that is, the fluidized gas velocity exceeds 5 Umf. If the fluidizing gas velocity in the chamber Rb is decreased from this state, the relative velocity of the fluidizing gas in the chamber Rb (relative velocity between the settling velocity of the fluid medium and the rising velocity of the fluidizing gas) exceeds about 2 Umf. As the fluidizing gas velocity in the chamber Rb is decreased, the pressure difference in the vicinity of the opening Py at the lower layer of the chamber Ra and the chamber Rb is increased, so that the moving amount of the fluid medium c from the chamber Rb to the chamber Ra is increased. . However, in the range where the relative fluidized gas velocity in the chamber Rb (relative velocity between the settling velocity of the fluidized medium and the rising velocity of the fluidized gas) is less than about 2 Umf, the lower the fluidized gas velocity in the chamber Rb, the lower the layer viscosity. Since the resistance force for the fluid medium c to pass through the opening Qy of the partition wall Y increases rapidly, the moving amount of the fluid medium c from the chamber Rb to the chamber Ra decreases conversely.
FIG. 4 shows three cases where the relative gas velocity of the fluidized gas ga in the chamber Ra (relative velocity between the sedimentation velocity of the fluidized medium and the rising velocity of the fluidized gas) is kept constant (4 Umf, 5 Umf, and 6 Umf). Shows how the moving amount of the fluid medium c from the chamber Ra to the chamber Rb changes when the gas velocity of the fluidizing gas gb in the chamber Rb is changed. As shown in FIG. 4, when the relative velocity of the fluidizing gas in the chamber Rb (the relative velocity between the sedimentation velocity of the fluidizing medium and the fluidizing gas) is less than about 2 Umf, the relative velocity of the fluidizing gas (the sedimentation velocity of the fluidizing medium) It can be seen that the amount of movement of the fluid medium c changes almost linearly with respect to the fluid velocity of the fluidizing gas. That is, by actively utilizing this range, a large change in the amount of movement of the fluid medium c can be caused by a slight change in the amount of fluidizing gas under a small amount of fluidizing gas. Further, FIG. 4 shows a case where the fluidization state of the chamber Ra is kept constant, but the fluidization state of the chamber Ra is kept in a sufficiently strong fluidization state as shown in the figure. Particularly preferred.
According to the knowledge of the inventors, the relative gas velocity of the fluidizing gas gb that gives the maximum amount of movement of the fluid medium c from the chamber Ra to the chamber Rb in FIG. Relative speed) is about 1.7 Umf. From the above viewpoint, the relative velocity of the fluidizing gas in the chamber Rb (the relative velocity between the sedimentation velocity of the fluidizing medium and the fluidizing gas) is preferably adjusted in the range of 1 Umf to 2 Umf, more preferably in the range of 1 Umf to 1.7 Umf. The fluidizing gas velocity in the chamber Ra is preferably 4 Umf or higher, more preferably 5 Umf or higher.
Even when the gas velocity of the fluidizing gas ga in the chamber Ra is increased while the gas velocity of the fluidizing gas gb in the chamber Rb is kept constant, or the gas velocity of the fluidizing gas ga in the chamber Ra is kept constant. Even when the gas velocity of the fluidizing gas gb in the chamber Rb is reduced, if the fluid medium c is not replenished from the outside or extracted to the outside, the fluid medium c from the chamber Rb side to the chamber Ra side is assumed. , The fluidized bed height of the chamber Rb decreases, and the fluidized bed height of the chamber Ra increases.
That is, assuming that the fluidizing gas velocities in the chamber Ra and the chamber Rb are the same, the difference in a certain amount is set so that the fluidizing gas velocity on the chamber Ra side is larger than the fluidizing gas velocity on the chamber Rb side. In this case, the fluid medium c moves from the chamber Rb side to the chamber Ra side immediately after making a difference, but when the fluidized bed height of the chamber Ra rises to some extent and the fluidized bed height of the chamber Rb falls, Since the pressure in the vicinity of the opening Qy in the lower layer of Ra is increased and the pressure in the vicinity of the opening Qy in the lower layer of the chamber Rb is decreased, the layers of the chamber Ra and the chamber Rb that are driving forces for moving the fluid medium c The pressure difference in the vicinity of the lower opening Qy is reduced. When this pressure difference becomes zero, the entire moving amount of the fluid medium c between the two chambers Ra and Rb becomes zero again.
Therefore, when a certain amount of difference is applied so that the fluidizing gas velocity in the chamber Ra is greater than the relative fluidizing gas velocity in the chamber Rb (the relative velocity between the settling velocity of the fluidizing medium and the rising velocity of the fluidizing gas). In order to continuously move the fluid medium c from the chamber Rb to the chamber Ra, the amount of the fluid medium c filled in both the chambers Ra and Rb, that is, the fluidized bed height is constant. A configuration may be employed in which the fluid medium c is supplied from the outside to the chamber Rb and the fluid medium c is extracted from the chamber Ra to the outside.
Next, a description will be given with reference to FIG. In FIG. 2C, the opening Pz is provided in the upper portion and the opening Qz is provided in the lower portion. Therefore, the phenomenon described above with reference to FIG. 2A occurs in the upper opening Pz. The phenomenon described above with respect to 2 (b) occurs.
Therefore, for example, when the fluidization state of the chamber Ra is made stronger than the fluidization state of the chamber Rb while the fluidization state of the chamber Rb is kept constant, the fluidization gas velocity of the chamber Ra is kept constant. When the fluidizing gas relative velocity in the chamber Rb (the relative velocity between the sedimentation velocity of the fluidizing medium and the fluidizing gas) is changed to be small, the fluidizing medium from the chamber Ra side to the chamber Rb side in the opening Pz. c moves, and in the opening Qz, the fluid medium c moves from the chamber Ra side to the chamber Rb side. Therefore, circulation of the fluid medium c occurs between the chamber Ra and the chamber Rb.
In this case, the amount of movement of the fluid medium c through the opening Qz and the amount of movement of the fluid medium c through the opening Pz are in the initial state where the fluidization state of the chamber Ra is stronger than the fluidization state of the chamber Rb. , Not necessarily equal. However, after a certain transient state, due to the change in the fluidized bed height caused by the difference in the amount of movement of the fluid medium c, the amount of movement of the fluid medium c through the openings Qz and Pz becomes equal, A circulating state of the fluid medium c is obtained.
For example, consider a case where the amount of movement of the fluid medium c from the chamber Rb to the chamber Ra via the opening Qz is larger than the amount of movement of the fluid medium c from the chamber Ra to the chamber Rb via the opening Pz. In this case, the fluidized bed height of the chamber Rb gradually decreases, and at the same time, the fluidized bed height of the chamber Ra gradually increases. A decrease in the fluidized bed height of the chamber Rb decreases the pressure near the hearth of the chamber Rb, while an increase of the fluidized bed height of the chamber Ra increases the pressure near the hearth of the chamber Ra. Thereby, the pressure difference between the chamber Ra and the chamber Rb across the opening Qz is reduced, that is, the amount of movement of the fluid medium c from the chamber Rb to the chamber Ra via the opening Qz is reduced. Further, the fluidized bed c in the chamber Ra rises, so that the fluid medium c easily jumps from the chamber Ra to the chamber Rb beyond the upper end of the partition wall Z. That is, the moving amount of the fluid medium c from the chamber Ra to the chamber Rb through the opening Pz increases. Due to the above effects, the amount of movement of the fluid medium c from the chamber Rb to the chamber Ra via the opening Qz decreases, and the amount of movement of the fluid medium c via the opening Pz from the chamber Ra to the chamber Rb increases. The fluidized bed heights of the chamber Ra and the chamber Rb further change, and balance is achieved where the amount of movement of the fluid medium c from the chamber Rb to the chamber Ra is equal to the amount of movement of the fluid medium c from the chamber Ra to the chamber Rb.
In the above, the moving amount (circulation amount) of the fluid medium c finally obtained by balancing is the shape of the furnace F such as the width, height, area and shape of the opening Qz and the height of the partition wall Z. And the amount of fluidized gas supplied to each chamber. Therefore, in order to obtain a desired circulation amount, the supply amount of the fluidizing gas amount is taken into consideration, such as the width, height, area and shape of the opening Qz, the height of the partition wall Z, and the like. What is necessary is just to determine the shape of the furnace F. FIG.
Here, with reference to FIG. 6, the definition of the circulation amount of the fluidized medium c circulating between the gasification chamber 1 and the settling char combustion chamber 4 through the opening 25 will be described below. In the figure, the gasification furnace 101 has the same configuration as that described in FIG. 1, but for the sake of easy understanding, the strong fluidization zone 1b of the gasification chamber 1 and the sedimentation which is the weak fluidization zone 4a. It is described so as to be constituted by the char combustion chamber 4 and the partition wall 15 in which the opening 25 is formed, and other components are omitted.
The superficial velocity of the fluidized gas g1 (FIG. 1) in the strong fluidization zone 1b of the gasification chamber 1 is V1b, and the fluidization gas g4 (FIG. 1) in the sedimentation char combustion chamber 4 which is the weak fluidization zone 4a is empty. The tower speed is V4a. Since the superficial velocity V1b is larger than the superficial velocity V4a (V1b> V4a), the fluidization state of the gasification chamber 1 is stronger than the fluidization state of the sedimentation char combustion chamber 4, and the bottom B4a of the sedimentation char combustion chamber 4 And the bottom B1b of the strong fluidization zone 1b of the gasification chamber 1 cause a pressure difference, and the fluid medium c circulates and moves through the opening 25 at the bottom of the partition wall 15 existing between the two fluidization zones. . The furnace bottom pressure (fluidized bed pressure at the furnace bottom) is Pm [Pa], and the bulk density of the fluidized bed is Df [kg / m. ³ ], Gravitational acceleration ga [kg / s ² If the height of the fluidized bed (bed height) is Hf [m],
Pm = Df × ga × Hf (1) The relationship is established.
The sedimentation char combustion chamber 4 is a weak fluidization zone 4a, and has a small number of bubbles, so the fluidized bed bulk density Df4a is large (there are few voids and the particle concentration is high). On the other hand, in the strong fluidization zone 1b of the gasification chamber 1, since there are many bubbles, the fluidized bed bulk density Df1b is small (there are many voids and the particle density is thin). Therefore, the fluidized bed bulk density Df4a of the settled char combustion chamber 4 (weak fluidization zone 4a) becomes larger than the fluidized bed bulk density Df1b of the strong fluidization zone 1b of the gasification chamber 1 (Df4a> Df1b). Occurs, and the fluid medium c moves from the char combustion chamber 4 (weak fluidization region 4a) toward the strong fluidization region 1b of the gasification chamber 1.
In contrast, as shown in FIG. 7, when the superficial velocity V1b of the strong fluidization zone 1b of the gasification chamber 1 is equal to the superficial velocity V4a of the sedimentation char combustion chamber 4 (V1b = V4a), the gas The furnace bottom pressure Pm1b in the furnace bottom B1b of the strong fluidization zone 1b of the conversion chamber 1 is equal to the furnace bottom pressure Pm4a in the furnace bottom B4a of the sedimentation char combustion chamber 4 (Pm1b = Pm4a). In the opening 25, when viewed macroscopically, the movement of the fluid medium c from the sedimentation char combustion chamber 4 to the strong fluidization zone 1b of the gasification chamber 1 is also caused by the fluidization medium c from the gasification chamber 1 to the sedimentation char combustion chamber 4. No movement occurs.
However, in the fluidized bed, which has the same superficial velocity in all fluidized zones in the fluidized bed, focusing on the particles one by one microscopically, the particles are constantly moving in any direction. In the opening 25 at the lower part of the partition wall 15 between the chamber 1 and the settled char combustion chamber 4, a bidirectional flow of the fluidized medium particles c is generated between the gasification chamber 1 and the settled char combustion chamber 4. Exchange of medium particles c has occurred.
The macro unidirectional movement of the fluid medium c between the gasification chamber 1 and the settling char combustion chamber 4 as shown in FIG. 6 is referred to as convection. The bidirectional movement of particles between the gasification chamber 1 and the settled char combustion chamber 4 of the fluid medium c as shown in FIG. 7 is referred to as diffusion. Even in the region where convection occurs in FIG. 6, when attention is paid to individual particles in a microscopic region, diffusion as shown in FIG. 7 occurs.
On the other hand, a mass flow rate [kg / s] of a macro one-way flow as shown in FIG. 6 is defined as a circulation amount. This circulation amount is determined by the pressure difference at the bottom of the fluidized bed, the viscosity of the upstream fluidized bed, and the viscosity of the downstream fluidized bed (in particular, the viscosity of the upstream fluidized bed is dominant). In FIG. 6, the larger the difference between the furnace bottom pressure Pm4a of the furnace bottom B4a of the sedimentation char combustion chamber 4 and the furnace bottom pressure Pm1b of the furnace bottom B1b of the gasification chamber 1, the more the through the opening 25 at the lower part of the partition wall 15. The moving amount (circulation amount) of the fluid medium c from the sedimentation char combustion chamber 4 to the gasification chamber 1 increases. Further, the opening 25 at the lower part of the partition wall 15 becomes a squeezing resistance against the flow of the fluid medium c. Therefore, the smaller the apparent viscosity of the fluidized bed in the settled char combustion chamber 4, the easier it is for the fluid medium c to flow through the squeezing resistance at the opening 25, and the amount of circulation increases. The apparent viscosity of the fluidized bed is determined depending on the fluidized state of the fluidized bed, that is, the superficial velocities V1b and V4a of the fluidized gas. Therefore, the apparent viscosity is changed by changing the fluidizing gas velocity V1b in the strong fluidizing zone 1b of the gasification chamber 1 or changing the superficial velocity V4a of the fluidizing gas in the sedimentation char combustion chamber 4. The amount of circulation can be controlled.
For example, if the fluidization state of the entire region of the gasification chamber 1 and the fluidization state of the entire region of the settling char combustion chamber 4 are the same, the circulation amount becomes zero. However, even if the circulation amount is set to 0 in this way, the fluid medium c is exchanged between the two chambers 1 and 4 by diffusion in the opening 25 at the lower part of the partition wall 15. As a result, the pyrolysis residue (excluding large residue that does not fluidize) in the strong fluidization zone 1b of the gasification chamber 1 moves to the settling char combustion chamber 4 and burns.
Therefore, the fluidized bed temperature is higher in the settled char combustion chamber 4 in which the residue combustion is performed than in the gasification chamber 1 in which the raw material is thermally decomposed as an endothermic reaction. Since the fluid medium c is exchanged between the two chambers 1 and 4 by diffusion in the opening 25 at the lower part of the partition wall 15, the sensible heat of the fluid medium c is also changed by the exchange of the fluid medium c. 4 are exchanged. Therefore, the sensible heat of the fluidized medium c moves from the settling char combustion chamber 4 having a high temperature to the gasification chamber 1 having a low temperature.
From the above, the fluidizing gas velocity (fluidizing gas superficial velocity) of the settled char combustion chamber 4, the circulation amount (convection), and the heat transfer amount have a relationship as shown in FIG. That is, when the superficial velocity of the fluid medium c in the sedimentation char combustion chamber 4 becomes zero, the circulation amount (convection) becomes zero, but the heat transfer amount does not become zero. This is because exchange of the fluid medium c occurs due to diffusion between the gasification chamber 1 and the char combustion chamber body 5 at the opening 21 below the partition wall 11 of the gasification chamber 1 and the char combustion chamber body 5. This is because there is residue transfer and heat transfer.
In FIG. 9, when the superficial velocity (unit is Umf) of the fluidizing gas in the sedimentation char combustion chamber 4 which is the weak fluidization zone 4a in which the fluid medium c settles is changed from 0 Umf to about 1.7 Umf. The change of the moving medium movement amount (convection + diffusion) (unit kg / s) from the sedimentation char combustion chamber 4 to the gasification chamber 1 is shown. As shown in the figure, the flow rate of the fluid medium increases almost linearly as the superficial velocity increases. Even when it is 1 Umf or less, the moving medium movement amount changes and is within the control range. Here, Umf is a unit in which the minimum fluidization speed (superficial speed of fluidization gas at which fluidization is started) is 1 Umf. Further, in the figure, when the fluidization speed of the sedimentation char combustion chamber 4 is set to 0, the moving medium moving amount from the sedimentation char combustion chamber 4 to the gasification chamber 1 is not 0. This is because the fluid medium moves due to diffusion between the openings 25 formed in the partition wall 15 between the gasification chamber 1 and the sedimentation char combustion chamber 4. Therefore, the fluidization state of the sedimentation char combustion chamber 4 is stopped, the amount of heat transfer by convection is set to 0, and the fluidization state around the opening 25 of the gasification chamber 1 and the sedimentation char combustion chamber 4 is changed (fluidization). By changing the amount of gas), it is possible to control the amount of heat transfer in a smaller range by changing the amount of heat transfer due to diffusion around the opening 25 of the gasification chamber 1 and the settled char combustion chamber 4. Become.
Therefore, the fluidized gas amounts g1 and g2 supplied to the region close to the opening 21 in the weak fluidization region 1a of the gasification chamber 1 and the region close to the opening 21 in the strong fluidization region 2b of the char combustion chamber main body 5 are obtained. By providing flow rate measuring devices 71 and 74 for measuring and flow rate control devices (for example, flow rate control valves 61 and 64) for changing the flow rate, diffusion by the gasification chamber 1 and around the opening of the char combustion chamber body 5 is caused. It becomes possible to control the amount of heat transfer.
For example, when it is desired to control the heat transfer amount to a small value, the control device 6 as the heat transfer amount control device sets the flow rate to 0 in the fluidizing gas flow rate control device (for example, the flow rate control valve 65) of the sedimentation char combustion chamber 4. Send a signal. As a result, fluidization of the settled char combustion chamber 4 is stopped, and movement of the fluid medium due to convection between the gasification chamber 1 and the char combustion chamber 2 does not occur. Furthermore, the control device 6 as the heat transfer amount control device is a fluidized gas amount control device (for example, a flow rate) that controls the fluidized gas g1 supplied to the region close to the opening 21 in the weakly fluidized region 1a of the gasification chamber 1. The control valve 61) and the fluidizing gas amount control device (for example, the flow control valve 63) for controlling the fluidizing gas g2 supplied to the region close to the opening 21 in the strong fluidizing region 2b of the char combustion chamber main body 5 Send a signal to lower. As a result, the amount of fluidized gas in the region close to the opening 21 in the weak fluidization region 1a of the gasification chamber 1 and in the region close to the opening 21 in the strong fluidization region 2b of the char combustion chamber main body 5 is reduced. The diffusion around the portion 21 is weakened, and the amount of heat transfer is reduced.
The relationship between the fluidized bed height and the circulation rate will be described with reference to FIG. In the figure, the furnace 102 includes two chambers Rp and Rq partitioned by a partition wall W. The chamber Rp and the chamber Rq store the fluid medium c. The partition wall W has an opening Pw at the top and an opening Qw at the bottom. A diffuser Dpa and a diffuser Dpb for blowing fluidized gas are provided at the furnace bottom of the chamber Rp, and a diffuser Dqa for blowing fluidized gas is provided at the furnace bottom of the chamber Rq. It is assumed that the upper end of the partition wall W is in the vicinity of the height of the interface, and the opening Qw is in a position that is submerged in the thick layer. The chamber Rp is divided into two sections: a weak fluidization zone pa that is weakly fluidized right above the diffuser Dpa, and a strong fluidized zone pb that is strongly fluidized just above the diffuser Dpb. The The chamber Rq is a weak fluidization zone qa having a weak fluidization state. The fluidization state is assumed to be uniform in the weak fluidization zone pa of the chamber Rp, in the strong fluidization zone pb of the chamber Rp, and in the chamber Rq. The strong fluidization zone pb of the chamber Rp has a furnace bottom Bpb, and the chamber Rq has a furnace bottom Bqa.
For the following two reasons, the higher the fluidized bed height, the greater the amount of circulation. As described above, by creating a pressure difference between the furnace bottom pressure Pmqa in the furnace bottom Bqa of the chamber Rq that is the weak fluidization zone qa and the furnace bottom pressure Pmpb of the furnace bottom Bpb in the strong fluidization zone pb of the chamber Rp, The fluid medium moves from the opening Qw below the partition wall W between the two regions. As described above, the pressure at the bottom of the furnace is obtained from Pm = Df × ga × Hf (1). Here, Pm [Pa] is the furnace bottom pressure, Df [kg / m ³ In the chamber Rq where the fluidized bed is a weakly fluidized zone qa, the number of bubbles is small, and the fluidized bed bulk density Dfqa is large (there are few voids and the particle concentration is high). In the strong fluidization zone pb of the chamber Rp, since there are many bubbles, the fluidized bed bulk density Dfpb is small (there are many voids and the particle density is thin). Therefore, the fluidized bed bulk density Dfqa of the chamber Rq, which is the weak fluidization zone qa, is larger than the fluidized bed bulk density Dfpb of the strong fluidization zone pb of the chamber Rp (Dfqa> Dfpb), and thus the furnace bottom Bqa of the chamber Rq. The furnace bottom pressure Pmqa of the chamber Rp is larger than the furnace bottom pressure Pmpb of the furnace bottom Bpb of the strong fluidization zone pb of the chamber Rp (Pmqa> Pmpb), and a pressure difference is generated from the chamber Rq in the weak fluidization zone qa. The fluid medium moves c through the opening Qw to the strong fluidization zone pb of the chamber Rp.
According to the equation (1), the higher the fluidized bed height, the proportionally the pressure Pmqa of the furnace bottom Bqa in the weak fluidization zone qa of the chamber Rq and the pressure Pmpb of the furnace bottom Bpb of the strong fluidization zone pb of the chamber Rp. Therefore, the higher the fluidized bed height, the greater the amount of movement. The greater the amount of fluid medium c that moves from chamber Rq to chamber Rp, the greater the amount of circulation (the first reason why the amount of circulation increases as the fluidized bed height increases).
As shown in FIG. 10, bubbles burst in the upper part of the strong fluidization zone pb of the chamber Rp, and the fluid medium c scatters to the surroundings due to the burst of the bubbles, and passes through the opening Pw from the chamber Rp to the chamber Rq. Movement of the fluid medium c occurs. The higher the fluidized bed height, the higher the distance (ΔH in the figure) from the upper end of the partition wall W between the chamber Rq and the chamber Rp to the upper surface of the fluidized bed, and the fluid medium c accompanying the bursting of bubbles in the upper part of the chamber Rp. Since the amount of the fluid medium c that moves to the chamber Rq increases due to the movement of the particles, the amount of circulation increases (the second reason that the amount of circulation increases as the bed height increases). The phenomenon that the fluid medium c moves to the chamber Rq due to the burst of bubbles at the upper part of the chamber Rp occurs in a limited range near the fluidized bed where the bubbles burst, so that the fluidized bed height exceeds a certain value. Even if it is increased, the movement of the fluid medium c does not increase.
Therefore, if it is within a certain range, the circulating amount can be increased by increasing the fluidized bed height. When it is desired to adjust the circulation amount during operation, the fluid medium c is supplied into the chamber Rq and the chamber Rp, the fluidized bed height is increased, the circulation amount is increased, or the fluid medium c is increased to the chamber Rq, chamber. It is possible to extract from Rp, lower the fluidized bed height, and reduce the circulation rate.
Next, a method for measuring the fluidized bed height will be described with reference to FIG. As shown in the figure, two pressure measuring devices 91 and 92 for the sedimented char combustion chamber 4 measure the fluidized bed pressure at two upper and lower points (preferably the same horizontal position) in the fluidized bed of the sedimented char combustion chamber 4. It is installed to do. By measuring the pressure with the pressure measuring devices 91 and 92, the fluidized bed height can be calculated and the circulation rate can be controlled. However, the pressure measurement location for calculating the fluidized bed height may be the gasification chamber 1 instead of the sedimentation char combustion chamber 4. First, the relationship between fluidized bed pressure and fluidized bed height will be described. There is a relationship described below between the fluidized bed pressure Pf and the fluidized bed height Hf.
Pf = Df × ga × Hfx + P0 (2)
Where Pf is the fluidized bed pressure [Pa], Df is the fluidized bed bulk density [kg / m. ³ ], Ga is the acceleration of gravity [kg / s ² ], Hfx is the fluid bed height [m] existing above, and P0 is the pressure [Pa] in the free board.
From the equation (2), if the fluidized bed pressure at the measurement point near the furnace bottom B4a is Pf1, and the upper fluidized bed height is Hfx1,
Pf1 = Df4a × ga × Hfx1 + P0 (2) ′
If the fluidized bed pressure at the measurement point far from the furnace bottom B4a is Pf2, and the upper fluidized bed height is Hfx2,
Pf2 = Df4a * ga * Hfx2 + P0 (2) "
It becomes. Here, when the distance between measurement points is ΔHf (known), ΔHf = Hfx1−Hfx2. Taking the difference between both formulas (2) ′ and (2) ″ representing the fluidized bed pressure,
Pf1−Pf2 = Df4a × ga × ΔHf (3)
The fluidized bed height can be calculated by the following steps. First, the fluidized bed pressures Pf1 and Pf2 at two upper and lower points in the fluidized bed (the same horizontal position is desirable) are measured, and the pressure difference ΔP (= Pf1−Pf2) of each fluidized bed pressure is calculated. Next, the fluidized bed bulk density Df4a is calculated from the equation (3) (the height ΔHf between the upper and lower two points is known). Since the value of the fluidized bed pressure at one of the measurement points (the height of the measurement bed is known and it is desirable to select the one closer to the furnace bottom B4a) and the pressure at the free board are almost zero, P0 From = 0, the height Hfx1 from the fluidized bed pressure measurement point to the upper surface of the fluidized bed is calculated using the formula (2) ′. If the fluidized bed height is Hf and the height of the measurement point near the furnace bottom B4a is Hf1 (known), Hf = Hf1 + Hfx1, and the fluidized bed height Hf is calculated from this equation.
Pressure measuring devices 91 and 92 are provided to measure the fluidized bed pressures Pf1 and Pf2, and pressure signals based on the measured values are sent from the pressure measuring devices 91 and 92 to the control device 6 as a computing unit. Hf can be calculated. By controlling the fluidized bed height Hf calculated in this way by the control device 6, the circulation amount can be controlled. The control device 6 may output a fluidized bed height signal representing the calculated fluidized bed height Hf.
The pressure measuring devices 91 and 92 are installed in the sedimentation char combustion chamber 4, the weak fluidization region 1 a of the gasification chamber 1, and the weak fluidization region 2 a of the char combustion chamber main body 5, where fluidization is slow and pressure fluctuation is small. However, it may be installed in the strong fluidization zone 1 b of the gasification chamber 1 and the strong fluidization zone 2 b of the char combustion chamber main body 5. The amount of circulation can be controlled by changing the fluidized bed height. In order to change the fluidized bed height, the fluidized medium is supplied when the fluidized bed height is increased, and the fluidized medium is extracted when the fluidized bed height is decreased. Therefore, in order to change the fluidized bed height, it is only necessary to provide a fluid medium supply device for supplying the fluid medium, supply the fluid medium, and provide a fluid medium extraction device for extracting the fluid medium to extract the fluid medium.
As shown in FIG. 22, the fluid medium supply device 111 measures the supply amount of the fluid medium c from the fluid medium storage device 112 that retains the fluid medium c and the fluid medium c from the fluid medium storage device 112 and supplies the fluid medium c. A fluid medium supply amount measuring device 113 that outputs a fluid medium supply amount signal i21 representing the amount, and a fluid medium supply amount control device 114 that controls the supply amount of the fluid medium c from the fluid medium storage tank in the fluid medium storage device 112. It is comprised including.
The fluid medium supply amount control device 114 is a control valve that is installed in a line 115 that, for example, freely drops the fluid medium from the fluid medium storage device 112 and conveys it to the gasification chamber 1, for example, and controls the amount of fluid medium c supplied. is there. The fluid medium supply amount measuring device 113 measures, for example, a change over time in the weight of the fluid medium storage tank in the fluid medium storage device 112, and obtains the fluid medium supply amount from the measured change over time.
The fluid medium supply amount control device 114 (for example, the aforementioned control valve) receives the fluid medium supply amount signal i21 from the fluid medium supply amount measurement device 113 and the fluid medium circulation amount signal described later from the control device 6 (FIG. 1). , Control the flow rate of fluid medium.
The fluid medium extraction device 116 includes, for example, a fluid medium extraction pipe 117 provided at the furnace bottom of the gasification chamber 1 and a fluid medium conveyance device 118 (screw conveyor, apron conveyor, etc.). The fluid medium c extracted and conveyed by the fluidized bed medium extraction device 116 is supplied to and stored in the fluid medium storage device 112 described above. The fluid medium extraction amount control device 119 (for example, the on / off switch of the screw conveyor or the rotation speed control device of the screw conveyor) is connected to the fluid medium extraction signal i22 from the fluid medium extraction amount measuring device 120 and the control device 6 (FIG. In response to a circulation amount signal described later from 1), a fluid medium extraction device drive signal i23 is sent to the fluid medium extraction device 116 to control the fluid medium extraction amount. Here, in the present embodiment, the fluid medium supply amount measuring device 113 and the fluid medium extraction amount measuring device 120 are the same, and for example, the change with time of the weight of the fluid medium storage tank in the fluid medium storage device 112 is measured. The amount of fluid medium extracted is determined from the measured change over time. The fluid medium extraction amount measurement device 120 is different from the fluid medium supply amount measurement device 113, and directly measures the conveyance amount of the fluid medium c conveyed by the fluid medium conveyance device 118 as the extraction amount. Also good.
Next, a method for measuring the circulation amount will be described with reference to FIG.
Like the sedimentation char combustion chamber 4, the pressure loss of the fluidized gas in the fluidized bed where the sedimentation flow of the fluidized medium c exists is larger than the pressure loss of the fluidized gas in the fluidized bed where there is no sedimentation flow. This is because the fluidizing gas is an upward flow, and therefore the resistance of the fluidizing gas is increased because the fluidizing gas is reverse to the settling flow of the fluid medium. Consider the pressure loss of fluidized gas between two upper and lower points (the same horizontal position is desirable) in the fluidized bed. When the resistance of the fluidizing gas when there is no settling flow of the fluidizing medium is Pn, and the resistance of the fluidizing gas when there is a settling flow of the fluidizing medium is Pd, the difference Pd−Pn between them is the settling flow of the fluidizing medium. The faster it gets, the bigger it becomes. By utilizing this phenomenon, the velocity of the settling flow of the fluid medium can be measured, and the circulation amount of the fluid medium c can be measured from the result.
That is, the circulation amount can be measured using the following phenomenon. (1) The larger the circulation amount, the faster the speed of the fluid medium sedimentation flow. (2) The higher the speed of the flowing medium sedimentation flow, the greater the pressure loss of the fluidizing gas. (3) The higher the fluidizing gas velocity Vg, the greater the pressure loss of the fluidizing gas.
For example, in the sedimentation char combustion chamber 4, the circulation amount can be measured using the following equation.
(Circulation amount) [kg / s] = (fluidized bed bulk density) [kg / m ³ ] X (fluid settling velocity) [m / s]) x (cross-sectional area of settling char combustion chamber) [m ² ] ... (1)
(Fluid settling velocity) = α × F1 (Pd−Pn) × F2 (Vg) (2)
For example, F1 which is a function of (Pd−Pn) and F2 which is a function of Vg can be expressed as follows.
F1 (Pd−Pn) = a0 + a1 × (Pd−Pn) + a2 × (Pd−Pn) ² + A3 × (Pd−Pn) ³ + ... ▲ 3 ▼
Or
F1 (Pd−Pn) = β (Pd−Pn) ^γ ... (4) F2 (Vg) = b0 + b1 * Vg + b2 * Vg ² + B3 × Vg ³ + ... ▲ 5 ▼
Or
F2 (Vg) = ξVg ^ζ ・ ・ ・ ▲ 6 ▼
Here, α, β, γ, ξ, ζ, a0, a1, a2, a3, ..., b0, b1, b2, b3, ... are constants determined by the shape of the gasification furnace 101. In the formulas (3) and (5), a third-order approximation is used, but a first-order approximation and a second-order approximation may be used.
Here, the pressure difference Pf1-Pf2 between the upper and lower points when there is no settling flow is Pf1-Pf2 = Pn, and the pressure difference Pf1-Pf2 between the upper and lower points when there is a settling flow is Pf1-Pf2 = Pd . For example, a state where there is no settling flow is generated under various conditions in the trial operation stage, the pressure between the upper and lower two points is measured, and the measured data is sent to the control device 6 (FIG. 1). The pressure difference Pn between them is calculated by the control device 6 and stored. The pressure between the upper and lower two points when there is a settling flow during the actual production gas production operation of the gasification furnace 101 is measured, the measured data is sent to the control device 6, and the upper and lower two points when there is a settling flow. The pressure difference Pd is calculated by the control device 6 and (Pd−Pn) is further calculated by the control device 6.
The flow rate of the fluidized gas g4 (FIG. 1) supplied to the settling char combustion chamber 4 (FIG. 1) is determined by the flow rate measuring device 75 (FIG. 1), and the flow rate signal i2 (FIG. 1) is sent to the control device 6. Therefore, the control device 6 can calculate the fluidized gas velocity Vg (Vg4) of the settling char combustion chamber 4.
Therefore, F2 is calculated by substituting Vg into the equation (5) (or equation (6)), and F1 is calculated by substituting (Pd−Pn) into the equation (3) (or equation (4)). Substituting F1 and F2 into equation (2), the fluid medium settling velocity is obtained. Substituting the fluidized bed sedimentation velocity thus obtained and the fluidized bed bulk density obtained from the above-mentioned equation (3) into the equation (1), α is known (it can be obtained empirically during a trial run or the like). The amount of circulation can be determined. The circulation amount can be controlled using the circulation amount thus obtained. That is, the gasification chamber layer temperature and the gasification chamber outlet gas composition can be controlled by controlling the amount of fluidized gas in the sedimentation char combustion chamber 4 so that the obtained circulation amount becomes an appropriate value. it can. The control device 6 may output a fluid medium circulation amount signal representing the circulation amount of the fluid medium.
As described above, the pressure measuring devices 91 and 92 for measuring the fluidized bed pressure at the upper and lower two points in the fluidized bed of the settled char combustion chamber 4 and the flow rate measuring device of the fluidized gas g4 in the settled char combustion chamber 4. (Flow rate measuring device) 75 (FIG. 1) and a control device 6 as a calculation device for calculating the circulation amount from the difference between the fluidized bed pressure at the upper and lower two points and the fluidized gas amount are provided, so the circulation amount is measured. be able to.
Based on the above-described principle, the amount of fluidized gas in the settling char combustion chamber 4 is an operating factor for controlling the circulation rate. Therefore, since the flow rate control valve (control valve) 65 (FIG. 1) for changing the fluidizing gas flow rate in the sedimentation char combustion chamber 4 is provided to control the circulation rate, the circulation rate control can be performed. it can.
The circulating amount can be controlled by combining the measurement of the fluidized bed height described above and the measuring of the circulating amount.
The amount of circulation is controlled as follows. First, the fluidized bed height is measured (step 1). In order to measure the fluidized bed height, the fluidized bed pressure at each point is measured by the pressure measuring devices 91 and 92 installed between two points in the fluidized bed. The measured value of the fluidized bed pressure is input to the control device 6 as an arithmetic unit for calculating the fluidized bed height, where the fluidized bed height is calculated. The calculated fluidized bed height is input to the control device 6 for controlling the circulation rate (data exchange is performed in the control device 6).
Next, the circulation amount is measured (step 2).
The measured values by the pressure measuring devices 91 and 92 installed between two points in the fluidized bed of the settled char combustion chamber 4 and the flow rate measuring device 75 installed for measuring the fluidized gas flow rate in the settled char combustion chamber 4. The measurement value is input to the control device 6 as a calculation device for calculating the circulation amount, and the control device 6 calculates the circulation amount. The calculated circulation amount is input to the control device 6 for circulation amount control (data exchange is performed in the control device 6).
Next, the circulation amount is controlled (step 3).
For example, when controlling the circulation amount of Wp to the circulation amount of Ws at a certain point in time, a signal corresponding to the measurement value Wp of the circulation amount calculated in step 2 and the circulation amount Ws to be set are associated. A signal is sent to the control device 6. If Ws <Wp, the control device 6 sends a signal to increase the fluidized bed height to the fluidized medium supply amount control device 114 (FIG. 22). If Ws> Wp, the control device 6 increases the fluidized bed height. A signal to lower is sent to the fluid medium extractor 118 (FIG. 22).
When the fluid medium supply amount control device 114 (FIG. 22) receives a signal to increase the fluidized bed height, the fluid medium supply amount control device 114, for example, opens a control valve opening to increase the fluid medium supply amount. To the control valve. As a result, when the opening degree of the control valve is opened, the fluidized medium is supplied into the furnace, the fluidized bed height is increased, and the circulation rate is increased. The fluid medium supply amount control device 114 also receives a signal from the fluid medium supply amount measurement device 113 (FIG. 22), and also performs an operation of determining the fluid medium supply amount so that the fluid medium is not suddenly supplied into the furnace. (Because the fluid medium stored in the fluid medium reservoir of the fluid medium storage device 112 (FIG. 22) is lower than the furnace temperature, the furnace temperature is prevented from being excessively lowered by the rapid supply of the fluid medium.
When the fluid medium extraction amount control device 119 (FIG. 22) receives a signal for lowering the fluidized bed height, it switches on, for example, a screw conveyor 118 (FIG. 22) for fluid medium extraction to reduce the fluid medium supply amount. Or a signal to increase the rotational speed of the screw conveyor. As a result, the screw conveyor is operated or the rotational speed of the screw conveyor is increased. As a result, the fluid medium is withdrawn from the furnace via the fluid medium extraction pipe 117 (FIG. 22). As a result, the fluidized bed height decreases and the circulation rate decreases.
With the above configuration, the circulation amount can be controlled by changing the fluidized bed height.
Next, a description will be given with reference to FIG. In the integrated gasification furnace 101 according to the present invention, the char combustion chamber main body 5 and the settled char combustion chamber 4 (partition wall X having an opening Px in the upper part) are partitioned by a partition wall 14 having an opening in the upper part. Gas chamber 1 and char combustion chamber partitioned by a partition wall 11 having an opening 21 at the bottom, and the movement of the fluid medium c between the chamber A and the chamber B (refer to FIG. 2A)) Movement of the fluid medium c between the main body 5 (corresponding to the chamber A and the chamber B (see FIG. 2B) partitioned by the partition wall Y having the opening Qy in the lower part), the partition having the opening 25 in the lower part Flow between sedimentation char combustion chamber 4 and gasification chamber 1 (corresponding to chamber A and chamber B partitioned by partition wall Y having opening Qy in the lower portion (see FIG. 2B)) partitioned by wall 15 Due to the movement of the medium c, the partition wall 12 having an upper opening and a lower opening 22 The heat recovery chamber 3 and the char combustion chamber main body 5 separated by a partition (corresponding to a chamber A and a chamber B partitioned by a partition wall Z having an upper opening Pz and a lower opening Qz (see FIG. 2C). )), By appropriately combining the movement of the fluid medium c between the two chambers, the fluid medium c can be continuously moved between adjacent chambers, and the amount of movement can be adjusted.
Inside the gasification chamber 1, near the surface in contact with the partition wall 15 between the settling char combustion chamber 4 and the fluidized state of the weakly fluidized zone 4 a in which the weakly fluidized state of the settling char combustion chamber 4 is maintained. The strong fluidization zone 1b is arranged as a section where a stronger fluidization state is maintained. As a whole, it is preferable to change the superficial velocity of the fluidized gas depending on the location so that the mixed diffusion of the injected fuel and the fluid medium c is promoted. As shown in FIG. In addition to the zone 1b, a weakly fluidized zone 1a is provided as a section in which a weakly fluidized state is maintained to form a swirling flow. In the strong fluidization zone 1b and the weak fluidization zone 1a, the fluidizing gas g1 has a uniform fluidization speed over the entire zone.
The char combustion chamber main body 5 has a weak fluidization zone 2a as a zone where a weak fluidization state is maintained at the center, and a strong fluidization zone 2b as a zone where a strong fluidization state is maintained at the periphery, The fluid medium c and the char h form an internal swirl flow. In the strong fluidization zone 2b and the weak fluidization zone 2a, the fluidizing gas g2 has a uniform fluidization speed over the entire zone. The fluidization speed of the strong fluidization zone 2b in the gasification chamber 1 and the char combustion chamber main body 5 is preferably 5 Umf or more, and the fluidization speed of the weak fluidization zone 2a is preferably 5 Umf or less. If there is a clear difference in fluidization speed relative to the zone 2a and the strong fluidization zone 2b, there is no particular problem even if this range is exceeded. It is preferable that a strong fluidization zone 2 b is arranged in a portion in contact with the heat recovery chamber 3 and the settled char combustion chamber 4 in the char combustion chamber main body 5. Further, a weak fluidization zone 3 a is arranged in the heat recovery chamber 3, and a weak fluidization zone 4 a is arranged in the sedimentation char combustion chamber 4. In the weak fluidization zone 3a and the weak fluidization zone 4a, the fluidizing gases g3 and g4 have a uniform fluidization speed over the entire zone. Further, it is preferable to provide a gradient at the bottom of the furnace so as to descend from the weak fluidization zone side to the strong fluidization zone side (not shown).
Thus, the fluidization state on the char combustion chamber body 5 side in the vicinity of the partition wall 12 between the char combustion chamber body 5 and the heat recovery chamber 3 is relatively stronger than the fluidization state on the heat recovery chamber 3 side. The fluidized medium c flows from the char combustion chamber body 5 side to the heat recovery chamber 3 side over the upper end of the partition wall 12 near the fluidized bed interface, and the flowing fluid medium c is heated. Due to the relatively weak fluidized state in the recovery chamber 3, that is, the high density state, it moves downward (toward the furnace bottom) and passes through the lower end (opening 22) near the furnace bottom of the partition wall 12 to recover heat. It moves from the chamber 3 side to the char combustion chamber main body 5 side. The fluid medium c passes through the opening 22 and moves from the heat recovery chamber 3 side to the char combustion chamber body 5 side. The fluid medium c in the vicinity of the opening 22 in the strong fluidization zone 2b of the char combustion chamber body 5 This is because the former is stronger than the latter when the fluidized state of the fluidized state of the fluidized medium c in the vicinity of the opening 22 of the weakly fluidized region 3a of the heat recovery chamber 3 is compared.
Similarly, the fluidization state on the char combustion chamber body 5 side in the vicinity of the partition wall 14 between the char combustion chamber body 5 and the sedimentation char combustion chamber 4 is relatively stronger than the fluidization state on the sedimentation char combustion chamber 4 side. By maintaining the fluidized state, the fluid medium c moves and flows from the char combustion chamber main body 5 side to the settled char combustion chamber 4 side over the upper end of the partition wall 14 in the vicinity of the fluid bed interface. The fluid medium c flowing into the settled char combustion chamber 4 side moves downward (toward the furnace bottom) due to the relatively weak fluidized state, that is, the high density state in the settled char combustion chamber 4. It moves from the sedimentation char combustion chamber 4 side to the gasification chamber 1 side through the lower end (the opening 25) near the furnace bottom. Here, the fluidized state of the fluid medium c in the vicinity of the opening 25 in the strong fluidization zone 1 b of the gasification chamber 1 and the fluidized medium c in the vicinity of the opening 25 in the weak fluidization zone 4 a of the sedimentation char combustion chamber 4. When compared with the fluidized state, the former is stronger than the latter. Thereby, the movement of the fluidized medium c from the settling char combustion chamber 4 to the gasification chamber 1 is assisted by an attraction action.
Similarly, the fluidization state on the char combustion chamber body 5 side in the vicinity of the partition wall 11 between the gasification chamber 1 and the char combustion chamber body 5 is relatively stronger than the fluidization state on the gasification chamber 1 side. It is kept fluidized. Therefore, the fluid medium c flows into the char combustion chamber main body 5 through the opening 21 below the boundary of the fluidized bed of the partition wall 11, preferably below the upper surface of the dense layer (submerged in the dense layer). . The fluid medium c moves from the gasification chamber 1 side to the char combustion chamber main body 5 side through the opening 21 because the fluid medium c in the vicinity of the opening 21 of the strong fluidization zone 2b of the char combustion chamber main body 5 is. This is because the former is stronger than the latter when the fluidized state of the fluidized state of the fluidized medium c in the vicinity of the opening 21 of the weakly fluidized region 1a of the gasification chamber 1 is compared.
As described above, the entire heat recovery chamber 3 is fluidized evenly, and is usually maintained in a fluidized state that is weaker than the fluidized state of the char combustion chamber main body 5 in contact with the heat recovery chamber 3 at the maximum. . Therefore, the superficial velocity of the fluidized gas g3 in the heat recovery chamber 3 is controlled between 0 and 3 Umf, and the fluid medium c forms a sedimented fluidized bed while gently flowing. Here, 0 Umf is a state in which the fluidized gas g3 is stopped. In such a state, heat recovery in the heat recovery chamber 3 can be minimized. That is, the heat recovery chamber 3 can arbitrarily adjust the amount of recovered heat within the maximum to minimum range by changing the fluidization state of the fluid medium c. Further, in the heat recovery chamber 3, the fluidization may be uniformly started / stopped or the strength of the chamber may be adjusted, but the fluidization of a part of the region may be stopped and the others may be placed in the fluidized state. However, the strength of the fluidized state in a part of the region may be adjusted.
Further, referring to FIG. 1, a method for adjusting the circulation amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber main body 5 will be specifically described below.
Changing the fluidizing gas velocity in the weak fluidizing zone 1a arranged on the gasifying chamber 1 side of the opening 21 provided at the lower end of the partition wall 11 that partitions the gasifying chamber 1 and the char combustion chamber main body 5. Thus, a case is considered in which the amount of movement of the fluid medium c from the gasification chamber 1 to the char combustion chamber body 5 through the opening 21 is increased. In this case, the amount of movement of the fluid medium c from the gasification chamber 1 to the char combustion chamber main body 5 through the opening 21 first increases, thereby increasing the fluidized bed height of the char combustion chamber main body 5 and the gas. The fluidized bed height of the chemical conversion chamber 1 is temporarily lowered.
As described above, due to such a change in the fluidized bed height, the movement of the fluidized medium c through the opening 21 acts in a direction to be suppressed, and balance is achieved in a certain state. On the other hand, the rise in the fluidized bed height of the char combustion chamber main body 5 causes an increase in the amount of the fluid medium c that jumps from the char combustion chamber main body 5 into the settled char combustion chamber 4 beyond the partition wall 14. As a result, the pressure at the bottom of the furnace of the sedimentation char combustion chamber 4 increases, while the pressure at the bottom of the gasification chamber 1 decreases due to the decrease in the fluidized bed height of the gasification chamber 1.
For this reason, when attention is paid to the opening 25 provided at the lower end of the partition wall 15 that partitions the gasification chamber 1 and the settling char combustion chamber 4, the pressure on the settling char combustion chamber 4 side increases, Since the pressure decreases, the amount of movement of the fluid medium c from the sedimentation char combustion chamber 4 to the gasification chamber 1 through the opening 25 increases using the pressure difference as a driving force.
In this way, the fluidized bed height changes due to the increase in the moving amount of the fluid medium c from the gasification chamber 1 to the char combustion chamber main body 5 given first, and therefore, the gasification chamber 1 to the char combustion chamber are changed. The increase in the amount of movement of the fluid medium c to the main body 5 is slightly canceled, and the amount of movement of the fluid medium c from the char combustion chamber main body 5 via the sedimentary char combustion chamber 4 to the gasification chamber 1 is increased. The effect is brought about. By this mechanism, the fluidized bed height between the gasification chamber 1 and the char combustion chamber main body 5 is finally adjusted so that the particle movement amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber main body 5 is balanced. However, the amount of particle movement in the stable state is kept increased from the initial state.
That is, in order to adjust the circulation amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber main body 5, the amount of movement of the fluid medium c from the gasification chamber 1 to the char combustion chamber main body 5 is set. It may be changed. Further, the moving amount of the fluid medium c from the char combustion chamber main body 5 to the gasification chamber 1 may be changed, or both of them may be changed. By changing the height, the amount of movement of the fluid medium c from the gasification chamber 1 to the char combustion chamber main body 5 and the char combustion chamber main body 5 can be changed only by performing an operation for changing one of the movement amounts. It is possible to stabilize in a state where the amount of movement of the fluid medium c to the gasification chamber 1 is balanced.
Therefore, in order to adjust the moving amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber main body 5, the char combustion chamber main body from the gasification chamber 1 through the opening 21 as described above. The amount of movement of the fluid medium c to 5 may be adjusted, or the amount of movement of the fluid medium c from the char combustion chamber body 5 to the settling char combustion chamber 4 beyond the upper end of the partition wall 14 may be adjusted. Alternatively, the moving amount of the fluid medium c from the sedimentation char combustion chamber 4 to the gasification chamber 1 through the opening 25 may be adjusted.
Here, in any of the methods, the movement amount of the fluid medium c is adjusted by changing the amount of the fluidizing gas g supplied from the furnace bottom, but the function of the gasification furnace 101 is ensured. In order to achieve this, by changing the supply amount of the fluidized gas g, the fuel gasification reaction performed in the gasification chamber 1 and the char combustion reaction performed in the char combustion chamber body 5 are not affected. It is desirable to do so. That is, it is desirable that the total amount of the fluidizing gas g1 supplied to the gasification chamber 1 or the total amount of the fluidizing gas g2 supplied to the char combustion chamber main body 5 is not changed.
For example, the supply amount of the fluidized gas g1 in the weak fluidization zone 1a near the opening 21 of the gasification chamber 1 is decreased, and the fluidization of the strong fluidization zone 2b in the vicinity of the opening 21 of the char combustion chamber body 5 is achieved. When adjusting to increase the amount of movement of the fluid medium c from the gasification chamber 1 to the char combustion chamber main body 5 through the opening 21 by increasing the supply amount of the gas g2, Increasing the amount of fluidized gas g1 supplied to the strong fluidized zone 1b of the opening 21 and decreasing the amount of fluidized gas g2 supplied to the weakly fluidized zone 2a of the opening 21 of the char combustion chamber main body 5 Therefore, it is desirable to perform an operation such that the total amount of the fluidized gases g1 and g2 supplied to the gasification chamber 1 and the char combustion chamber main body 5 is not changed.
In addition, the supply amount of the fluidized gas g2 in the strong fluidization zone 2b near the partition wall 14 of the char combustion chamber main body 5 is increased, and the partition wall 14 is passed from the char combustion chamber main body 5 to the settled char combustion chamber 4. In the case where adjustment is made so that the moving amount of the fluid medium c from the char combustion chamber main body 5 to the settled char combustion chamber 4 is increased by increasing the amount of the fluid medium c that jumps in, the char combustion chamber main body 5 By reducing the amount of fluidized gas g2 supplied to the weakly fluidized zone 2a away from the partition wall 14, an operation is performed so that the total amount of fluidized gas g2 supplied to the char combustion chamber body 5 does not change. It is desirable.
On the other hand, when adjusting the amount of movement of the fluid medium c from the settled char combustion chamber 4 to the gasification chamber 1 through the opening 25, the flow to the gasification chamber 1 or the char combustion chamber main body 5 is performed. The amount of movement of the fluid medium c can be adjusted only by changing the supply amount of the fluidizing gas g4 to the sedimentation char combustion chamber 4 without changing the supply amounts of the chemical gases g1 and g2. is there.
In this case, the portion close to the opening 25 on the gasification chamber 1 side is a strong fluidization zone 1b, so that it is kept in a strong fluidization state, and the sedimentation char combustion chamber 4 side is a weak fluidization zone 4a as a compartment, so that it weakly flows. Since the strong fluidization state of the strong fluidization zone 1b on the gasification chamber 1 side is kept constant, the strength of the weak fluidization state on the sedimentation char combustion chamber 4 side is changed. The amount of movement of the fluid medium c from the sedimentation char combustion chamber 4 to the gasification chamber 1 can be adjusted effectively.
As already described, it is desirable that the strong fluidization zone 1b in the vicinity of the opening 25 on the gasification chamber 1 side is maintained in a strong fluidization state, and the fluidization gas velocity is preferably 4 Umf or more, and more preferably. Should be kept above 5 Umf. In this case, the fluidizing gas velocity in the sedimentation char combustion chamber 4 is in the range of 4 Umf or less (when the flow rate of the fluidizing gas in the strong fluidizing zone 1b is 4 Umf or more) or in the range of 5 Umf or less (flowing in the strong fluidizing zone 1b). 4), the amount of movement of the fluid medium c from the settling char combustion chamber 4 to the gasification chamber 1 can be adjusted according to the characteristics shown in FIG.
Note that, according to FIG. 4, when the fluidizing gas velocity on the settling char combustion chamber 4 side is changed preferably in the range of 1 Umf to 2 Umf, more preferably in the range of 1 Umf to 1.7 Umf, It can be seen that the amount of movement changes largely linearly. In this case, the amount of the fluidizing gas g4 supplied to the settling char combustion chamber 4 can be reduced and the amount of movement of the fluid medium c can be finely adjusted.
Of course, on the contrary, the flow from the sedimentation char combustion chamber 4 to the gasification chamber 1 is changed by changing the state of strong fluidization of the gasification chamber 1 while keeping the state of weak fluidization of the sedimentation char combustion chamber 4 constant. It is also possible to change the moving amount of the medium c. However, in that case, the change in the flow rate of the fluidizing gas g1 for changing the moving amount of the fluid medium c becomes large, and the conditions for the gasification reaction in the gasification chamber 1 also change, which is not preferable. That is, as will be described later, in practice, changing the layer temperature of the gasification chamber 1 is very important in controlling the properties of the product gas b. When the temperature is changed, the reaction conditions of the gasification chamber 1 change with the change of the layer temperature, and it becomes difficult to independently control only the layer temperature of the gasification chamber 1. On the other hand, in the case of controlling the movement amount of the fluidized medium c by changing the weakly fluidized state of the settled char combustion chamber 4 described above, the change in the flow rate of the fluidized gas g4 is very small. In addition, since it is possible to realize a large change in the moving amount of the fluid medium c (see FIG. 4), in addition to advantages such as good controllability and little influence on the efficiency of the entire process, the gas medium 1 is supplied to the gasification chamber 1. There is a great advantage that the layer temperature of the gasification chamber 1 can be controlled without changing the flow rate of the fluidizing gas g1.
Next, control of the gas velocity of the fluidized gas g will be described with reference to FIG. First, control of the gas velocity of the fluidized gas g1 supplied to the gasification chamber 1 will be described. As described above, the control valve 61 installed in the supply pipe 51 connected to the air diffuser 31 disposed in the furnace bottom corresponding to the weak fluidization zone 1 a of the gasification chamber 1 is controlled by the control device 6. In response to the signal i1, the valve opening is set. A fluidizing gas g 1 having a flow rate corresponding to the valve opening degree is supplied to the air diffuser 31 through the control valve 61. The fluidizing gas g1 is supplied to the weak fluidizing zone 1a at a fluidizing gas speed determined by the flow rate of the fluidizing gas supplied. The flow rate of the fluidizing gas g1 is measured by a flow rate measuring device 71 installed downstream of the control valve 61 on the supply pipe 51, and the measured flow rate is sent from the flow rate measuring device 71 to the control device 6 as a flow rate signal i2. It is done. The control device 6 compares the measured flow rate signal i2 with the target flow rate stored in the weakly fluidized zone 1a, and sets the value of the control signal i1 to the control valve 61 so that the flow rate signal i2 approaches the target value. The changed control signal i1 is sent from the control device 6 to the control valve 61.
The control of the gas velocity of the fluidized gas g1 in the weakly fluidized zone 1a of the gasification chamber 1 has been described above, but the strong fluidized zone 1b of the gasification chamber 1, the weakly fluidized zone 2a of the char combustion chamber 2, and the strong The same applies to the fluidization zone 2b, the weak fluidization zone 4a, and the weak fluidization zone 3a of the heat recovery chamber 3.
The target value of the flow rate of the fluidizing gas g1 supplied to the weak fluidization zone 1a of the gasification chamber 1 and the target value of the flow rate of the fluidizing gas g1 supplied to the strong fluidization zone 1b are the target gasification chamber. 1 the strength of the fluidized state inside, the amount of movement of the fluid medium c moving from the weak fluidization zone 1a of the gasification chamber 1 to the weak fluidization zone 1a of the char combustion chamber main body 5 through the opening 21; The amount of movement of the fluid medium c moving from the settling char combustion chamber 4 to the strong fluidization zone 1b of the gasification chamber 1, the bed temperature of the gasification chamber 1 measured by the temperature measuring device 42, and the gas composition measuring device 46 are measured. Considering the gas composition of the generated gas b comprehensively, the layer temperature of the gasification chamber 1 becomes a predetermined value (for example, 600 to 800 ° C.), or the gas composition has a predetermined content (for example, H ₂ The / CO molar ratio may be determined to be 2.6 to 5.8).
The target value of the flow rate of the fluidized gas g2 supplied to the weakly fluidized zone 2a of the char combustion chamber 2 and the target value of the flow rate of the fluidized gas g2 supplied to the strong fluidized zone 2b are The target value of the flow rate of the fluidized gas g4 to be supplied is the strength of the fluidized state in the target char combustion chamber main body 5, the strength of the fluidized state in the target settling char combustion chamber 4, The amount of movement of the fluid medium c that moves from the strong fluidization zone 2 b of the char combustion chamber body 5 to the sedimentation char combustion chamber 4 beyond the upper end of the partition wall 14, and gasification from the sedimentation char combustion chamber 4 through the opening 25. The amount of movement of the fluid medium c that moves to the strong fluidization zone 2b of the chamber 1 and the amount of movement of the fluid medium c that moves from the heat recovery chamber 3 to the strong fluidization zone 2b of the char combustion chamber body 5 through the opening 22 , Beyond the upper end of the partition wall 12 from the strong fluidization zone 2b of the char combustion chamber body 5 The total amount of the moving medium c moving to the heat recovery chamber 3 and the bed temperature of the char combustion chamber main body 5 measured by the temperature measuring device 43 are comprehensively taken into consideration, and the bed temperature of the char combustion chamber main body 5 is predetermined. The gasification residue (char, tar, etc.) supplied from the gasification chamber 1 may be determined to be completely combusted at a value (for example, 850 to 950 ° C.).
When the heat recovery chamber 3 is provided, the layer temperature of the char combustion chamber main body 5 is affected by the amount of heat recovered in the heat recovery chamber 3, and if the amount of heat recovery increases, the layer temperature of the char combustion chamber main body 5 is increased. If the heat recovery amount decreases, the bed temperature of the char combustion chamber main body 5 increases.
Next, a control method for increasing or decreasing the heat recovery amount in the heat recovery chamber 3 will be described. The amount of heat recovered in the heat recovery chamber 3 is determined by the heat transfer coefficient between the fluid medium c and the in-layer heat transfer tube 41A. This heat transfer coefficient is closely related to the strength of fluidization in the heat recovery chamber 3. The stronger the fluidization, the larger the heat transfer coefficient, and the more the heat transfer tube in the layer takes heat from the fluid medium. Therefore, in order to keep the bed temperature of the char combustion chamber main body 5 constant, by controlling the flow rate of the fluidizing gas g3 supplied to the fluidized bed of the heat recovery chamber 3, fluidization in the heat recovery chamber 3 is controlled. What is necessary is just to change strength.
The control valve 66 installed in the supply pipe 56 for introducing the fluidized gas g3 supplied to the heat recovery chamber 3 receives the control signal i1 from the control device 6 and sets the valve opening. A fluidizing gas g3 having a flow rate corresponding to the valve opening degree is supplied to the fluidized bed of the heat recovery chamber 3 through the control valve 66. The flow rate of the fluidizing gas g3 is measured by a flow rate measuring device 76 installed downstream of the control valve 66, and the measured flow rate is sent to the control device 6 as a control signal i2. As described above, the greater the flow rate of the fluidized gas g3, the stronger the fluidization of the heat recovery chamber 3, and the greater the amount of heat recovery. Therefore, when the bed temperature of the char combustion chamber body 5 is higher than the target value, The control device 6 may be configured to change the value of the control signal i1 to the control valve 66 so that the bed temperature of the char combustion chamber body 5 approaches the target value and increase the flow rate of the fluidized gas g3. . When the layer temperature of the char combustion chamber body 5 is lower than the target value, the control device 6 sets the value of the control signal i1 to the control valve 66 so that the layer temperature of the char combustion chamber body 5 approaches the target value. What is necessary is just to change and to comprise so that the flow volume of fluidization gas g3 may be decreased.
On the other hand, for the steam, the control valve 67 installed in the introduction part 41B of the in-layer heat transfer tube 41 receives the control signal i1 from the control device 6 and sets the valve opening. Steam s1 having a flow rate corresponding to the valve opening degree is supplied to the in-layer heat transfer tube main body 41A via the control valve 67. The steam s1 introduced into the in-layer heat transfer tube main body 41A receives heat from the fluid medium c as a heat transfer coefficient determined by the fluidization state of the heat recovery chamber 3 and is heated to become superheated steam s2, which is discharged from the discharge unit 41C. The The flow rate of the steam s1 is measured by a flow rate measuring device 77 installed on the downstream side of the control valve 67 on the introduction part 41B, and the measured flow rate is sent from the flow rate measuring device 77 to the control device 6 as a flow rate signal i2. . The temperature of the steam s1 before overheating is measured by a temperature measuring device 44 installed in the introduction part 41B, and the measured temperature is sent to the control device 6 as a temperature signal i3. The temperature of the steam s2 after overheating is measured by a temperature measuring device 45 installed in the discharge unit 41C, and the measured temperature is sent to the control device 6 as a temperature signal i3.
For example, when the heat recovery amount is increased by increasing the strength of fluidization in the heat recovery chamber 3, assuming that the flow rate of the steam s1 supplied to the in-layer heat transfer tube 41 is kept constant, the obtained superheated steam s2 Temperature rises. When it is not preferable that the temperature rises due to the usage form of the superheated steam s2, the increase in the heat recovery amount is reflected in the increase in the flow rate of the recovered superheated steam s2 by increasing the flow rate of the supplied steam s1. Can be made. In this case, when the temperature signal i3 of the steam s2 after overheating is higher than the target temperature of the steam s2, the control device 6 changes the value of the control signal i1 to the control valve 67 and increases the flow rate of the steam s1. What is necessary is just to comprise. Conversely, when the temperature signal i3 of the steam s2 after overheating is lower than the target temperature of the steam s2, the value of the control signal i1 to the control valve 67 may be changed to reduce the flow rate of the steam s1. .
A relatively large incombustible material contained in the waste or the fuel a is discharged from an incombustible material discharge port (not shown) provided at the furnace bottom of the gasification chamber 1. Further, the bottom surface of the furnace in each chamber may be horizontal, but the bottom of the furnace may be inclined according to the flow of the fluid medium c in the vicinity of the furnace bottom so as not to form a staying part of the fluid medium c. The incombustible discharge port (not shown) may be provided not only at the furnace bottom of the gasification chamber 1 but also at the furnace bottom of the char combustion chamber body 5, the sedimentation char combustion chamber 4, or the heat recovery chamber 3.
The most preferable fluidizing gas g1 in the gasification chamber 1 is to boost the generated gas b for recycling. In this way, the product gas b exiting from the gasification chamber 1 is only the product gas b generated purely from the fuel, and a very high quality product gas b can be obtained. If this is not possible, a gas (oxygen-free gas) containing as little oxygen as possible, such as water vapor, carbon dioxide (CO2), or combustion exhaust gas obtained from the char combustion chamber 2, may be used as the fluidizing gas g1. When the bed temperature of the fluidized medium c decreases due to the endothermic reaction during gasification, if necessary, supply flue gas having a temperature higher than the thermal decomposition temperature, or add oxygen or oxygen in addition to the oxygen-free gas. A part of the product gas b may be burned by supplying a gas, for example, air. The fluidizing gases g2 and g4 supplied to the char combustion chamber 2 supply a gas containing oxygen necessary for char combustion, for example, air, a mixed gas of oxygen and steam. When the calorific value (calorie) of the fuel a is low, it is preferable to increase the amount of oxygen, and oxygen is supplied as it is. The fluidizing gas g3 supplied to the heat recovery chamber 3 uses air, water vapor, combustion exhaust gas, or the like.
A portion above the upper surface of the fluidized bed (the upper surface of the splash zone) of the gasification chamber 1 and the char combustion chamber 2, that is, the free board portion, is completely partitioned by the partition walls 11 and 15. Furthermore, since the part above the upper surface of the dense bed of the fluidized bed, that is, the splash zone and the freeboard part, are completely partitioned by the partition walls, the free board part of each of the char combustion chamber 2 and the gasification chamber 1 Even if the pressure balance is somewhat disturbed, the disturbance can be absorbed by only a slight change in the difference in the position of the interface between the two fluidized beds or the difference in the position of the upper surface of the dense layer, that is, the fluidized bed height difference. That is, since the gasification chamber 1 and the char combustion chamber 2 are partitioned by the partition walls 11 and 15, even if the pressure in each chamber fluctuates, this pressure difference can be absorbed by the fluidized bed height difference. Such a layer can be absorbed until it falls to the upper ends of the openings 21 and 25. Therefore, the upper limit value of the pressure difference between the free boards of the char combustion chamber 2 and the gasification chamber 1 that can be absorbed by the fluidized bed height difference is the gas from the upper ends of the openings 21 and 25 below the partition walls 11 and 15 that partition each other. It is approximately equal to the head difference between the head of the fluidizing chamber fluidized bed and the head of the char combustion chamber fluidized bed.
However, in the above case, when a slight disturbance in the pressure balance is absorbed by the fluidized bed height difference, the amount of movement of the fluidized medium c between the chambers changes according to the change in the fluidized bed height. Therefore, in order to keep the moving amount of the fluid medium c between the chambers constant, it is important to add a control mechanism that minimizes the disturbance of the pressure balance.
With reference to FIG. 1, a control method for suppressing disturbance in pressure balance will be described below. The product gas b exhausted from the gasification chamber 1 and the char combustion gas e exhausted from the char combustion chamber 2 are exhausted via a pressure control valve 78 or a control valve 79 installed in the subsequent stage, respectively. Used.
Here, in FIG. 1, the control valve 78 and the control valve 79 are depicted as being installed immediately after the gas is exhausted from the gasification chamber 1 or the char combustion chamber 2, but it passes through other devices. Even if the control valve 78 or the control valve 79 is installed after that, by adjusting the opening degree of the control valve 78 or the control valve 79, the resistance of gas discharge from the corresponding gasification chamber 1 or char combustion chamber 2 can be reduced. Any change is possible as long as the pressure in the gasification chamber 1 or the char combustion chamber 2 can be changed. Pressure measuring devices 81 and 82 as pressure measuring devices are respectively installed in the free board portion of the gasification chamber 1 and the free board portion of the char combustion chamber 2, and the pressures in the respective chambers 1 and 2 are detected. The pressure signal i5 is sent to the control device 6. The control device 6 compares the pressure signal i5 of the free board portion of the gasification chamber 1 with the pressure signal i5 of the free board portion of the char combustion chamber 2, and the difference is the amount of movement between the chambers of the fluid medium c. Within a certain range that does not affect, preferably the pressure difference between the two chambers 1 and 2 is ± 10% or less, more preferably ± 5% or less of the pressure loss of the fluidized bed in the gasification chamber 1 or the char combustion chamber 2. Preferably, the control signal i1 is sent to the control valve 78 or the control valve 79 so that the pressures in the two chambers 1 and 2 are equal, and the opening degree of the control valve 78 or the control valve 79 is changed.
In the integrated gasification furnace 101 described above, three gasification chambers, 1, a char combustion chamber 2, and a heat recovery chamber are provided in each fluidized bed furnace via a partition wall, and further, a char combustion chamber. 2, the gasification chamber 1, the char combustion chamber 2, and the heat recovery chamber 3 are provided adjacent to each other. Since this integrated gasification furnace 101 enables the circulation of a large amount of fluid medium c between the char combustion chamber 2 and the gasification chamber 1, a sufficient amount of heat for gasification can be obtained only by sensible heat of the fluid medium c. Can supply.
Further, in the integrated gasification furnace 101 described above, since the seal between the char combustion gas e and the product gas b is perfected, the pressure balance control between the gasification chamber 1 and the char combustion chamber 2 is performed well, and the combustion gas e And the product gas b are not mixed, and the properties of the product gas b are not deteriorated.
Further, the fluid medium c and char h as the heat medium flow from the gasification chamber 1 side to the char combustion chamber 2 side, and the same amount of fluid medium c from the char combustion chamber 2 side to the gasification chamber. Since it is configured to return to the 1 side, it is necessary to transport the fluid medium c mechanically using a conveyor or the like in order to naturally balance the mass and return the fluid medium c from the char combustion chamber 2 side to the gasification chamber 1 side. In addition, there are no problems such as difficulty in handling high-temperature particles and large sensible heat loss.
Next, control of the gas composition of the product gas b of the integrated gasifier 101 will be described with reference to FIG.
In the present invention, the fluidized bed temperatures of the gasification chamber 1 and the char combustion chamber 2 are adjusted by adjusting the moving amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber 2, that is, the internal circulation amount as described above. Is intended to be arbitrarily controlled in practice, or to change the composition of the product gas b generated from the gasification chamber 1. For this reason, in the operation of the integrated gasifier 101, the control device 6 is instructed to give a change in the fluidized gas amount. That is, a control signal i1 for controlling the flow rate is sent from the control device 6 to the control valves 61 to 67, and the control valves 61 to 67 adjust the fluidizing gas flow rate. Adjusting the fluidizing gas flow rate is adjusting the fluidizing gas velocity. When the fluidizing gas velocity is adjusted, the amount of internal circulation is adjusted, whereby the fluidized bed temperature of the gasification chamber 1 and the char combustion chamber 2 and the composition of the product gas b generated from the gasification chamber 1 are changed. It is preferable to configure the control logic in the control device 6 so as to measure how it changes and to adjust the amount of fluidized gas based on the result.
For example, the case where the amount of internal circulation is adjusted for the purpose of changing the fluidized bed temperature of the gasification chamber 1 will be described below.
Specifically, when the fluidization gas velocity of the sedimentation char combustion chamber 4 is in a weak fluidization state in the range of about 1 Umf to 2 Umf, the measured value of the temperature measuring device 42 of the fluidized bed temperature of the gasification chamber 1 is the target. Let us consider a case where the temperature is lower than the fluidized bed temperature of the gasification chamber 1. In this case, as already explained, by increasing the amount of fluidized gas in the sedimentation char combustion chamber 4 within the range of 1 Umf to 2 Umf, the fluidized bed viscosity of the sedimentation char combustion chamber 4 is lowered (see FIG. 3), and sedimentation is performed. The moving amount of the fluid medium c from the char combustion chamber 4 to the gasification chamber 1 can be increased (see FIG. 4).
As described above, when the amount of movement of the fluid medium c from the settling char combustion chamber 4 to the gasification chamber 1 increases at this time, the bed height of the gasification chamber 1 temporarily rises, whereby the gasification chamber The moving amount of the fluid medium c from 1 to the char combustion chamber 2 increases, and the bed height of the char combustion chamber 2 also increases slightly. Then, the amount of the flow medium c jumped from the char combustion chamber 2 to the settling char combustion chamber 4 also increases. As a result, the gasification chamber 1 to the char combustion chamber 2, the char combustion chamber 2 to the settling char combustion chamber 4, and the settling char combustion The moving amount of all the fluid mediums c from the chamber 4 to the gasification chamber 1 is stabilized in a state where it is increased from the initial state. At this time, the temperature difference between the gasification chamber 1 and the char combustion chamber 2 decreases due to an increase in the amount of movement of the fluid medium c between the gasification chamber 1 and the char combustion chamber 2. That is, the fluidized bed temperature in the gasification chamber 1 rises and the fluidized bed temperature in the char combustion chamber 2 falls. In the following description, the moving amounts of all the fluid media c from the gasification chamber 1 to the char combustion chamber 2, from the char combustion chamber 2 to the settling char combustion chamber 4, and from the settling char combustion chamber 4 to the gasification chamber 1 are stabilized to the same value. In this state, the moving amount of the fluid medium c between the gasification chamber 1 and the char combustion chamber 2 is referred to as an “internal circulation amount”.
If the fluidized bed temperature in the gasification chamber 1 is stable after a certain period of time and the stable temperature is still lower than the target fluidized bed temperature, the amount of fluidized gas in the settling char combustion chamber 4 is reduced. What is necessary is just to increase further. If the stable temperature is higher than the target fluidized bed temperature, the amount of fluidized gas in the settling char combustion chamber 4 may be reduced somewhat.
The above operation is performed by inputting the measured value and the target value of the fluidized bed temperature of the gasification chamber 1 to the control device 6 including the arithmetic device by the configuration as shown in FIG. It is easy by changing the control signal i1 to the control valve 65 and changing the opening of the control valve 65 so as to change the supply amount of the fluidized gas g4 to the sedimentation char combustion chamber 4 based on the size. Can be realized.
In the above description, the weak fluidization zones 1a, 2a, 3a, 4a, and the strong fluidization zones 1b, 2b have been described as having the air diffusers 31-36 to which the respective control valves 61-66 are connected.
However, as shown in FIG. 5 (a part of the integrated gasification furnace 101 is omitted), for example, the weak fluidization zone 1a and the strong fluidization zone 2b sandwiching the opening 21 are directly adjacent to the opening 21, respectively. Separating the neighborhood areas 1ax and 2bx into the remote areas 1ay and 2by other than the neighborhood areas 1ax and 2bx, the diffuser devices 31 and 34 are connected to the neighborhood areas 31x and 34x corresponding to the neighborhood areas 1ax and 2bx, respectively, You may comprise so that it may isolate | separate into the remote parts 31y and 34y corresponding to 1ay and 2by.
The supply pipes 51 and 54 are connected to the remote portions 31y and 34y of the air diffusers 31 and 34, respectively, and the flow rate measuring devices 71x and 74x and the control valve 61x are connected to the vicinity portions 31x and 34x of the air diffusers 31 and 34, respectively. You may make it connect the supply piping 51x and 54x in which 64x was installed. Instead of controlling the speeds of the fluidizing gases g1 and g2 supplied to control the amount of movement of the fluid medium c through the opening 21 over the entire weak fluidizing zone 1a and strong fluidizing zone 2b, respectively. In addition, the gas flow rates of the fluidized gases g1 and g2 supplied from the neighboring areas 1ax and 2bx may be controlled. This control is performed by controlling the control valves 61x and 64x by the control device 6 (see FIG. 1) as described above.
Similarly, the weak fluidizing zone 4a, the strong fluidizing zone 1b, and the weak fluidizing zone 3a and the strong fluidizing zone 2b that sandwich the opening 22 are adjacent to the openings 25 and 22 (not shown). The velocity of the fluidized gas supplied to control the amount of movement of the fluidized medium c through the openings 25 and 22 is reduced to a weakly fluidized region. 4a, 3a, strong fluidization zones 1b, 2b, instead of controlling over the entire region, the gas flow rate of the fluidized gas supplied from the neighborhood may be controlled respectively.
The phenomenon that occurs when the amount of internal circulation is changed from one stable operating state of the integrated gasification furnace 101, and the obtained effects will be described below. First, a change in the bed temperature of the gasification chamber 1 or the char combustion chamber 2 occurs in response to a change in the internal circulation amount. When the amount of internal circulation is increased, the bed temperature of the gasification chamber 1 increases and the bed temperature of the char combustion chamber 2 decreases. Conversely, when the amount of internal circulation is reduced, the layer temperature of the gasification chamber 1 decreases and the layer temperature of the char combustion chamber 2 increases.
Further, in both the gasification chamber 1 and the char combustion chamber 2, the residence time of the fluid medium c in the chambers 1 and 2 changes. For example, when the internal circulation amount is reduced to ½, the residence time of the fluid medium c in each of the chambers 1 and 2 is doubled. On the contrary, when the internal circulation amount is doubled, the residence time of the fluid medium c in each of the chambers 1 and 2 is halved.
In addition, the amount of char h generated in the gasification chamber 1 changes. For example, when the amount of internal circulation is decreased, the amount of char h generated in the gasification chamber 1 increases, reflecting the decrease in the layer temperature of the gasification chamber 1. In general, the amount of char h generated increases as the layer temperature decreases. When the amount of internal circulation is increased, the amount of char h generated decreases due to an increase in the bed temperature of the gasification chamber 1. In general, the amount of char h generated decreases as the layer temperature of the gasification chamber 1 increases.
Reflecting the change in the amount of char h generated and the change in the bed temperature of the gasification chamber 1, the gas composition of the product gas b generated in the gasification chamber 1 changes. This is due to the change in the element balance (molar ratio (%) of carbon, hydrogen, oxygen, etc.) due to the change in the amount of char h generated (the amount of combustibles moving from the gasification chamber 1 to the char combustion chamber 2). Due to changes in the equilibrium state of the gas component with temperature.
Due to the change in the composition of the product gas, the H ₂ / CO ratio, gas heating value, etc. change. The H2 / CO ratio is an important factor related to the production efficiency of hydrogen, liquid fuel, etc. from the product gas b. The calorific value of gas is an important factor when the produced gas b is used by combustion.
From the above, by changing the amount of internal circulation, the layer temperature of the gasification chamber 1 is arbitrarily controlled in practice, and thereby the composition of the product gas b (H ₂ , CO, CO ₂ , CH ₄ , H ₂ In addition to mol% such as O, the concept includes factors determined by the product gas composition, such as H2 / CO ratio and gas heating value. ) Can be changed.
In this case, for example, when the control is performed so that the layer temperature of the gasification chamber 1 is lowered, the layer temperature of the char combustion chamber 2 is correspondingly increased. Conversely, if the control is performed to increase the layer temperature of the gasification chamber 1, the layer temperature of the char combustion chamber 2 correspondingly decreases. Since the operating temperature of the char combustion chamber is preferably maintained within the optimum temperature range, preferably 850 to 950 ° C., for completely burning the char h and tar that have moved from the gasification chamber 1, the internal circulation amount is changed. Thus, when the layer temperature of the gasification chamber 1 is changed, it is necessary to adjust the temperature of the char combustion chamber 2 by another method so that the temperature does not deviate from the optimum range.
For this purpose, as described above, when the heat recovery chamber 3 is provided, the heat recovery amount in the heat recovery chamber 3 is controlled so as to keep the bed temperature of the char combustion chamber main body 5 constant. be able to. Moreover, even if control is performed so that the combustion amount of the combustible component in the char combustion chamber is directly changed by supplying a part of the raw material used directly to the char combustion chamber or changing the supply amount thereof. Good. Further, when the temperature of the char combustion chamber 2 becomes very high, control is performed such that water is supplied to the fluidized bed portion or the temperature of the fluidized bed is directly cooled by changing the supply amount. May be performed.
Below, an example of the trial calculation result supposing the integrated gasification furnace 101 (FIG. 1) is shown (FIGS. 11, 13 to 15). The raw material a was made of woody biomass, the gasification chamber 1 was gasified with steam at 200 ° C., and the char combustion chamber 2 burned char h with air. The layer temperature of the char combustion chamber 2 is kept constant at 900 ° C. by controlling the heat recovery amount of the heat recovery chamber 3, and how the layer temperature of the gasification chamber 1 changes when the internal circulation amount is changed. Along with this, it was estimated how the composition of the generated gas b and the calorific value change. The internal circulation amount is organized by a dimensionless number (hereinafter referred to as “circulation ratio”) obtained by dividing the circulation amount (kg / h) of the medium particles by the input amount (kg / h) of the raw material a.
FIG. 11 shows the relationship between the amount of internal circulation (circulation ratio) and gasification chamber layer temperature (unit: ° C.) in case 1, and FIG. 12 shows the amount of internal circulation (circulation ratio) and gasification chamber layer temperature (unit: unit 2) in case 2. ° C) relationship. 11 and 12 show the calculation results. Although the absolute value of the gasification chamber layer temperature to be lowered varies depending on the scale of the gasification furnace 1, the raw material a, and the process conditions (fluidized steam, air, etc.), as shown in FIG. 11 and FIG. As the (circulation ratio) decreases, the layer temperature of the gasification chamber 1 decreases, and as the internal circulation amount (circulation ratio) increases, the layer temperature of the gasification chamber 1 increases. For example, in FIG. 11 (Case 1), the internal circulation amount for maintaining 700 ° C. is about 44% (20/45) based on the internal circulation amount for maintaining the layer temperature of the gasification chamber 1 at 800 ° C. The circulation rate for maintaining the temperature at 600 ° C. is about 22% (10/45). From the above, in order to be able to control the layer temperature of the gasification chamber 1 in the range of 600 to 800 ° C., the internal circulation amount of the fluid medium c is practically arbitrary in the range of about 20% of the maximum value to the maximum value. It is preferable to be configured so that it can be changed. Typically, the amount of internal circulation is controlled so that the bed temperature of the gasification chamber 1 is constant.
FIG. 13 shows the relationship between the internal circulation rate (circulation ratio) and the product gas composition. This figure is a calculation result when it is assumed that the gas residence time in the gasification chamber 1 is sufficiently long, or when the reaction proceeds to a state close to the equilibrium composition by a catalyst or the like.
As shown in the figure, the lower the internal circulation rate (circulation ratio), the lower the layer temperature of the gasification chamber 1, so that the composition of the product gas b is H ₂ CO decreases, CO ₂ , H ₂ O increases. Especially when the amount of internal circulation (circulation ratio) is small and the temperature of the gasification chamber 1 is low, CH ₄ Significantly increases the amount of H ₂ CO decreases correspondingly. By changing the internal circulation amount (circulation ratio), it is possible to control to obtain a gas composition shown in a desired diagram.
Fig. 14 shows the amount of internal circulation (circulation ratio) and H of the product gas. ₂ The relationship of / CO ratio is shown. This figure is a calculation result when it is assumed that the gas residence time in the gasification chamber 1 is sufficiently long, or when the reaction proceeds to a state close to the equilibrium composition by a catalyst or the like.
As shown in the figure, the smaller the internal circulation amount (circulation ratio) is, the more H ₂ / CO ratio increases. Therefore, by controlling the internal circulation amount (circulation ratio), H ₂ It is possible to control / CO to a desired value between the ratios 2.6 and 5.7.
FIG. 15 shows the relationship between the internal circulation amount (circulation ratio) and the generated gas heat generation amount. This figure is a calculation result when it is assumed that the gas residence time in the gasification chamber 1 (FIG. 1) is sufficiently long, or when the reaction proceeds to a state close to the equilibrium composition by a catalyst or the like.
As shown in the figure, as a whole, the CO concentration decreases as the internal circulation amount (circulation ratio) decreases in response to the change in the product gas composition, so that the generated gas heat generation amount tends to decrease. In particular, when the amount of internal circulation (circulation ratio) is small and the layer temperature of the gasification chamber 1 is low, CH ₄ Since the concentration increases, the calorific value increases. By changing the internal circulation rate (circulation ratio), about 10,600 to about 10,900 (HHV DB) kJ / m ³ It can be controlled to a desired value between NTP.
When the gas residence time in the gasification chamber 1 is short and the gas composition is different from the equilibrium composition, the following phenomenon occurs.
The first control of gas properties of the gasification furnace 101 (FIG. 1) will be described. FIG. 16 shows the relationship between the gasification chamber layer temperature (unit: ° C.) and the gasification chamber (GC) outlet gas calorific rate (tar is counted as the calorific value) (unit%) when the gasification raw material a is biomass. Indicates. When the gasification chamber layer temperature is low, there is little sensible heat loss, so the amount of heat generated from the gasification chamber outlet gas is high, and when the gasification chamber layer temperature is high, there is much sensible heat loss. Outlet gas heat generation is reduced. Since there is a dependency relationship between the gasification chamber layer temperature and the circulation rate, the heat generation amount of the gasification chamber outlet gas can be increased by reducing the circulation rate. Gasification chamber outlet calorific value is the percentage of the calorific value of gas (including tar) generated from unit weight gasification raw material at the gasification chamber outlet divided by the calorific value due to combustion of gasification raw material of unit weight. Say.
FIG. 17 shows the gasification chamber layer temperature (unit ° C.) and cold gas efficiency (unit%) when the gasification raw material a is biomass (determined based on the calorific value of combustible gas excluding tar at the gasification chamber outlet). The relationship is shown. When the gasification chamber layer temperature is low, tar generation increases, so that the cold gas efficiency decreases. When the gasification chamber layer temperature is high, tar generation decreases, and thus the cold gas efficiency increases. The cold gas efficiency refers to a percentage obtained by dividing the calorific value of gas (not including tar) generated from a unit weight of gasified raw material at the gasification chamber outlet by the calorific value due to combustion of the unit weight of gasified raw material.
FIG. 18 shows the internal circulation amount (circulation ratio) and the generated gas calorific value (excluding tar) (HHV DB) (unit KJ / m) when the gasification raw material a is biomass. ³ -NPT) relationship. If the amount of internal circulation (circulation ratio) is small, the gasification chamber layer temperature becomes low, and tar generation increases, so the amount of heat generation decreases, and if the amount of internal circulation (circulation ratio) is large, the gasification chamber layer temperature becomes high. This reduces tar generation and increases the amount of heat generated.
FIG. 19 shows the relationship between the gasification chamber layer temperature (unit: ° C.) and the ratio (unit%) at which carbon (C) in the raw material a is transferred to tar when the gasification raw material a is biomass. The figure shows that the lower the gasification chamber layer temperature, the greater the amount of tar generation, and the higher the gasification chamber layer temperature, the smaller the amount of tar generation.
Therefore, in order to increase the cold gas efficiency in the raw material a having a large tar generation amount such as biomass and a low calorific value, (1) reducing the sensible heat loss by lowering the gasification chamber layer temperature, and There are methods of decomposing (reducing molecular weight) the tar generated at that time, or (2) increasing the circulation amount to increase the gasification chamber layer temperature to suppress the amount of tar generation.
Next, the second gas property control of the gasification furnace 101 (FIG. 1) will be described.
By controlling the amount of circulation, the amount of volatile matter released from the gasification raw material a can be controlled, and the amount of carbon in the raw material a transferred to the char combustion chamber 2 can be controlled.
FIG. 20 shows the amount of circulation (unit kg / h) when the gasified raw material a is biomass, and the rate of transfer of carbon in the raw material a supplied to the gasification chamber 1 to the char combustion chamber 2 (unit%). ). The figure shows that when the amount of circulation increases, the proportion of unreleased carbon transferred to the char combustion chamber 2 increases as the volatile content increases, and when the amount of circulation decreases, carbon that has not been released as volatile content enters the char combustion chamber 2. It shows that the rate of migration becomes smaller.
In FIG. 21, when the gasification raw material a is biomass, the gasification chamber layer temperature (unit: ° C.) and the ratio of transition to the char burning chamber 2 of carbon in the gasification raw material a supplied to the gasification chamber 1 The relationship with (unit%) is shown. When the layer temperature is high, the amount of volatile matter released is large (the remaining amount of volatile matter is small) and the volatile matter release rate is fast, so the proportion of carbon in the raw material a transferred to the char combustion chamber 2 is considered to be small. However, the opposite is true in the figure. That is, when the gasification chamber layer temperature is high, the rate at which carbon in the raw material a is transferred to the char combustion chamber 2 increases, and when the gasification chamber layer temperature is low, the carbon in the raw material a is the char combustion chamber 2. The rate of transition to becomes smaller. This means that the gasification chamber layer temperature is high, that is, the circulation amount is large, and the gasified raw material a (here, biomass) that has not released volatile matter is char-combusted along with the fluidized medium. It is shown that the transition to chamber 2 is dominant.
From the above, since it is possible to control the combustion amount in the char combustion chamber 2 by controlling the circulation amount, the combustion amount in the char combustion chamber 2 is changed according to the fluctuation of the gasification raw material a. It can be controlled optimally.
It should be noted that the illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention.

  The gasification furnace according to the present invention includes a gasification chamber, a char combustion chamber, and a control device. Therefore, by adjusting the strength of the weak fluidized state, the gasification furnace is provided between the gasification chamber and the char combustion chamber. The composition of the gas generated from the gasification chamber can be controlled by controlling the amount of the fluid medium that circulates, and the control characteristics can be further improved.

Claims (4)

A gasification chamber in which a high-temperature fluid medium is caused to flow inside to form a gasification chamber fluidized bed having a first interface, and an object to be treated is gasified in the gasification chamber fluidized bed;
A high-temperature fluid medium is caused to flow inside to form a char combustion chamber fluidized bed having a second interface, and char generated by gasification in the gasification chamber is combusted in the char combustion chamber fluidized bed. a gasifier Ru and a char combustion chamber for heating the flowing medium;
A fluid medium supply device for supplying a fluid medium to the gasifier;
A fluid medium extraction device for extracting the fluid medium from the gasification furnace ;
The gasification chamber and the char combustion chamber are partitioned by a partition wall so that there is no gas flow vertically above the interface between the fluidized beds, and the gasification chamber and the char combustion chamber are disposed below the partition wall. The communication port that communicates with the char combustion chamber, wherein the communication port is formed with a communication port whose upper end height is equal to or lower than the first interface and the second interface, and sandwiches the communication port. The fluidized state of the fluidized medium in the vicinity of the communication port of one of the chamber and the char combustion chamber is stronger than the fluidized state of the fluidized medium in the vicinity of the communication port of the other chamber, and through the communication port. A fluid medium is circulated from the weak fluidized state to the strong fluidized state;
Further, by supplying the fluid medium by the fluid medium supply device and extracting the fluid medium by the fluid medium extraction device, at least one fluidized bed layer of the gasification chamber and the char combustion chamber. Provided with a control device for controlling the circulating amount of the fluid medium by changing the height ;
Gasification furnace. A pressure measuring device for measuring pressure at two upper and lower points in the at least one fluidized bed is provided, and a bed height of the fluidized bed is obtained from a difference in pressure at the two points;
  The gasifier according to claim 1. Flowing a hot fluid medium to form a gasified fluidized bed having a first interface;
  A gasification step of gasifying the workpiece in the gasification fluidized bed;
  Flowing a high-temperature fluidized medium to form a char-combusted fluidized bed having a second interface; and burning the char generated by gasification in the gasification step in the char-combusted fluidized bed A char combustion process for heating
  A fluidized medium supply step of supplying a fluidized medium from outside the gasified fluidized bed and the char combustion fluidized bed to at least one of the gasified fluidized bed and the char combustion fluidized bed;
  A fluid medium extraction step for extracting the fluid medium from the at least one to the outside of the gasification fluidized bed and the char combustion fluidized bed;
  The gasified fluidized bed and the char combustion fluidized bed are partitioned by a partition wall so that there is no gas flow vertically above the interface between the fluidized beds, and the gasification fluidized bed is disposed below the partition wall. A communication port that communicates the fluidized bed with the char combustion fluidized bed, wherein a communication port having a height at an upper end of the communication port equal to or lower than the first interface and the second interface is formed. The fluidized state of the fluidized medium in the vicinity of the communicating port of one fluidized bed of the gasified fluidized bed and the char combustion fluidized bed sandwiched between the fluidized state of the fluidized medium in the vicinity of the communicating port of the other fluidized bed Stronger, configured to circulate the fluid medium through the communication port from the weak fluidized state to the strong fluidized state;
  And a control step of controlling the circulation amount of the fluid medium by changing the at least one bed height by performing the fluid medium supply step and the fluid medium extraction step;
  Gasification method. A pressure measuring step of measuring pressure at two upper and lower points in the at least one is performed, and a bed height of the fluidized bed is obtained from a difference in pressure at the two points;
  The gasification method according to claim 3.

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