KR102157483B1 - Solid fuel supply device and combustion equipment and method of operating the solid fuel supply device - Google Patents

Abstract

An object of the present invention is to suppress the amount of air from the inside of the crusher passing through the reservoir, to maintain the pressure inside the crusher, and to suppress an increase in installation cost and deterioration of maintenance properties. The solid fuel supply device 3 supplies coal-mixed biomass fuel as a solid fuel to the pulverizer 2 that supplies the pulverized fuel obtained by pulverizing the solid fuel to the boiler body 4. The solid fuel supply device 3 includes a bunker 25 for storing coal-mixed biomass fuel supplied to the inside of the pulverizer 2 and a biomass fuel conveying device 23 for conveying the biomass fuel to the bunker 25. ), and a coal supply device 24 for mixing coal and biomass fuel conveyed to the bunker 25. The coal supply device 24 mixes coal so that the mixing ratio of coal in the coal-mixed biomass fuel stored in the bunker 25 is 4 weight% or more and 50 weight% or less.

Description

A solid fuel supply device and a combustion facility, and an operation method of a solid fuel supply device TECHNICAL FIELD [SOLID FUEL SUPPLY DEVICE AND COMBUSTION EQUIPMENT AND METHOD OF OPERATING THE SOLID FUEL SUPPLY DEVICE}

The present invention relates to a solid fuel supply device for supplying a carbon-containing solid fuel to a grinder, a combustion facility, and a method of operating the solid fuel supply device.

Among the solid fuels containing carbon supplied to combustion devices such as boilers or integrated coal gasification combined cycle (IGCC), biomass fuels adhere to carbon dioxide in the process of biomass growth. carbon neutral), and is attracting attention as one of the measures to reduce carbon dioxide emissions from fossil fuel boilers. Biomass fuel, such as a wood type, is introduced into a pulverizer in the form of chips or pellets, pulverized with a pulverizer, and then supplied to a burner provided in a boiler.

[0003] In a grinder for pulverizing biomass fuel, there is an apparatus of Patent Document 1, for example. In Patent Literature 1, biomass fuel transported by a truck is put into a supply hopper through various devices and stored. The biomass fuel stored in the supply hopper is discharged to a weighing belt conveyor by a predetermined amount through a supply feeder, and after being quantified by this weighing belt conveyor, it is passed through a double flap gate to a male roller mill. Is supplied.

Japanese Laid-Open Patent No. 2008-208360

By the way, since chips and pellets of biomass fuel before pulverization have a large particle diameter and light weight, a gap formed between each biomass fuel when biomass fuel is stored in a reservoir such as a supply hopper ( The gap formed between the biomass fuel and the adjacent biomass fuel) increases.

Usually, a gas for conveyance for conveying a pulverized solid fuel, which is a pulverized solid fuel, is supplied to the inside of the crusher, so that the pressure increases. Further, the storage portion communicates with the inside of the grinder in order to supply solid fuel to the inside of the grinder.

Thereby, when only the biomass fuel is stored in the reservoir, it is intended to prevent the conveyance gas such as air blown out from the inside of the crusher and the pulverized fuel from passing through the gap formed between the respective biomass fuels. There is a possibility that the sealing property in the storage portion decreases, and the pressure inside the crusher decreases. Various problems in the operation of the pulverizer, such as deterioration of biomass transportability or generation of dust in the storage part when the conveying gas is blown through the storage part, and decrease in the pressure inside the pulverizer, decreases the conveyance amount of pulverized fuel There is a possibility of occurrence.

In the apparatus of Patent Document 1, the air in the male roller mill is prevented from passing through the supply feeder through a double flap gate between the male roller mill and the supply feeder. However, since a double flap gate is provided between the male roller mill and the supply feeder, installation cost increases, and maintenance for the double flap gate is required, so there is a possibility that the operability of the male roller mill may decrease.

The present invention has been made in view of such circumstances, and by suppressing the flow rate of the reverse flow due to the pumping up of the pulverized fuel and the conveying gas from the inside of the pulverizer passing through the reservoir, the pressure inside the pulverizer is preferably maintained and installed. An object of the present invention is to provide a solid fuel supply device, a combustion facility, and a method of operating a solid fuel supply device capable of suppressing an increase in cost and a reduction in operability.

In order to solve the above problems, the solid fuel supply device and combustion facility of the present invention and a method of operating the solid fuel supply device employ the following means.

A solid fuel supply device according to an aspect of the present invention is a solid fuel supply device for supplying biomass fuel and coal as the solid fuel to a pulverizer for supplying pulverized fuel obtained by pulverizing solid fuel to a boiler. A storage unit for storing the solid fuel supplied therein, a biomass fuel transfer unit for transferring biomass fuel to the storage unit, and a coal mixing unit for mixing coal with the biomass fuel conveyed to the storage unit The coal mixing unit mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 4% by weight or more and 50% by weight or less.

In the above configuration, coal is mixed with the biomass fuel conveyed to the storage unit. Accordingly, the solid fuel stored in the reservoir is a mixture of biomass fuel and coal. Since coal has a smaller particle diameter than biomass fuel, it enters the gap formed between the biomass fuels stored in the reservoir. Thereby, since coal blocks the gap formed between the biomass fuels, it becomes difficult for the conveying gas such as air and the pulverized fuel to pass through the reservoir, and the conveying gas and the pulverized fuel are sprayed from the inside of the crusher passing through the reservoir. It can suppress the flow rate that is raised and flows back. Therefore, it is possible to preferably maintain the pressure inside the grinder.

Further, by mixing coal with a particle diameter smaller than that of biomass fuel, the surface area of the entire solid fuel stored in the reservoir is increased. When the surface area of the entire solid fuel stored in the storage portion increases, the pressure loss between the transport gas and the finely divided fuel passing through the gap between the stored solid fuel increases. Thereby, since it becomes difficult for the conveyance gas and the finely divided fuel to pass through the storage part, the conveyance gas and the finely divided fuel are blown up from the inside of the crusher passing through the storage part, and the flow rate which flows back can be suppressed. Therefore, it is possible to preferably maintain the pressure inside the grinder.

In addition, since there is no need to provide a special device such as a storage unit, a rotary valve between the storage unit and the pulverizer, for suppressing the flow rate backflow by spraying the gas for conveyance and the finely divided fuel from the inside of the pulverizer passing through the storage unit. In addition, it is possible to suppress an increase in installation cost and suppress a decrease in mechanical operability.

In addition, since the coal mixing unit mixes coal so that the mixing ratio of the coal in the solid fuel stored in the reservoir is 4% by weight or more and 50% by weight or less, solid fuel mainly composed of biomass fuel can be supplied to the boiler. have.

In addition, in the solid fuel supply device according to an aspect of the present invention, the coal mixing unit is the coal mixture so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 5% by weight or more and 10% by weight or less. You may mix.

If the mixing ratio of the coal to be mixed is small, coal does not sufficiently enter the gap formed between the biomass fuels stored in the reservoir, and the gas for conveyance and the pulverized fuel pass through the gap from the inside of the crusher. There is a possibility that the pressure inside the grinder cannot be maintained preferably.

On the other hand, if the mixing ratio of coal to be mixed is large, for example, when the crusher is configured in an appropriate configuration for processing biomass fuel (e.g., the shape of the housing, the rotational speed of the crushing table, the rotational speed of the rotary classifier, etc.) There is a possibility that coal with different properties than biomass fuel cannot be properly treated. If the pulverized fuel of coal that cannot be properly treated in the pulverizer increases, there is a possibility that the operation state of the boiler changes, resulting in a decrease in combustibility.

Therefore, in the above configuration, the mixing ratio of coal to be mixed is set at 5% by weight or more and 10% by weight or less. Thereby, while maintaining the pressure inside the pulverizer suitably, it is possible to prevent a deterioration in the operating state of the boiler.

In addition, a solid fuel supply device according to an aspect of the present invention includes a supply unit provided between the storage unit and the pulverizer and supplying the solid fuel stored in the storage unit to the pulverizer, and a temperature in the supply unit is measured. A temperature measuring device to be used may be provided, and the coal mixing unit may change the mixing ratio of the coal based on the temperature measured by the temperature measuring device.

Since the high temperature conveyance gas is supplied into the grinder, the temperature of the conveyance gas such as air in the grinder increases.

In the above configuration, since the supply unit is provided between the storage unit and the pulverizer, when the transport gas and the pulverized fuel in the pulverizer pass through the storage unit, the supply unit also circulates. The temperature of the conveying gas in the grinder is high because the high temperature conveyance gas flows in the grinder. When the conveying gas and the pulverized fuel in the grinder flow through the supply section, the temperature in the supply section rises. In the above configuration, the temperature measuring instrument measures the temperature in the supply section. Accordingly, it is possible to reliably detect whether or not the conveying gas and the pulverized fuel in the grinder flow backward and pass through the reservoir by the temperature in the supply section. In addition, since the mixing ratio of coal is changed based on the measured temperature, the mixing ratio of the coal can be appropriately adjusted according to the flow rate of the pulverized fuel and the conveying gas passing through the reservoir, more preferably the crusher passing through the reservoir. The gas for conveyance and the finely divided fuel from the inside of the gas are blown up and the flow rate backflowing can be suppressed.

In addition, since the supply unit is provided between the storage unit and the crusher, the temperature measuring instrument measures the temperature in the vicinity of the crusher relatively when the conveying gas is blown up and the backflow occurs, so that the conveying gas is greatly cooled in other structures. It does not work, and it can be detected by measuring it with a temperature measuring instrument at a relatively high temperature. Therefore, when the temperature measuring instrument measures the temperature, it is difficult to be affected by other environments. Therefore, it is possible to accurately determine whether the conveying gas and the pulverized fuel are passing through the reservoir.

Further, a combustion facility according to an aspect of the present invention includes the solid fuel supply device according to any one of the above, a pulverizer for pulverizing the solid fuel supplied by the solid fuel supply device, and the solid fuel pulverized with the pulverizer. It has a combustion part supplied with.

According to the above configuration, the pressure inside the pulverizer can be preferably maintained by suppressing the flow rate in which the conveying gas and the pulverized fuel are blown up from the inside of the pulverizer passing through the storage unit and flow back. Thereby, the supply of the coal biomass fuel supplied to the pulverizer 2 can be stabilized, and the solid fuel can be preferably processed in the pulverizer. Accordingly, it is possible to improve the energy efficiency of the entire combustion facility by appropriately adjusting the properties and conditions of the pulverized fuel supplied to the combustion unit.

In addition, a method of operating a solid fuel supply device according to an aspect of the present invention is a solid fuel supply device that supplies biomass fuel and coal as the solid fuel to a pulverizer that supplies pulverized fuel obtained by pulverizing solid fuel to a boiler. As an operating method of, the solid fuel supply device includes a storage unit for storing the solid fuel supplied to the inside of the pulverizer, a biomass fuel transport process for transporting the biomass fuel to the storage unit, and the storage unit And a coal mixing process of mixing coal with the biomass fuel conveyed to the biomass fuel, wherein in the coal mixing process, the mixing ratio of the coal in the solid fuel stored in the reservoir is 4% by weight or more and 50% by weight. The coal is mixed so as to be below.

Advantageous Effects of Invention According to the present invention, by suppressing the flow rate of the reverse flow due to spraying of the gas for conveyance and the pulverized fuel from the inside of the crusher passing through the reservoir, the pressure inside the crusher is preferably maintained, and the increase in installation cost is suppressed. And suppression of a decrease in operability can be achieved.

1 is a schematic configuration diagram of a boiler facility according to a first embodiment of the present invention;
2 is a graph showing the relationship between the mixing ratio of coal and the sealing property, and the relationship between the mixing ratio of coal and the combustibility;
Fig. 3 is a diagram showing a model in a state of orderly arrangement of a large particle diameter;
Fig. 4 is a diagram showing a model of a compact arrangement state of a small particle diameter;
5 is a graph showing the relationship between small particle autonomy and sealability;
6 is a schematic configuration diagram of a boiler facility according to a second embodiment of the present invention;
7 is a flowchart showing a process of changing the mixing ratio of coal.

Hereinafter, an embodiment of a solid fuel supply device and a method of operating a boiler facility and a solid fuel supply device according to the present invention will be described with reference to the drawings.

[First Embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1.

Fig. 1 shows a boiler installation 1 provided with a pulverizer 2, a solid fuel supply device 3, and a boiler body (combustion unit) 4 according to the present embodiment. In addition, in the present embodiment, the vertical upward direction is indicated upward and the vertical downward direction is indicated downward.

The boiler facility (combustion facility) 1 is provided with a pulverizer 2 that mainly pulverizes biomass fuel, which is a solid fuel supplied to a burner 9 provided in the boiler body 4. Here, the biomass fuel is an organic resource derived from a renewable organism, and for example, wood-based biomass fuel such as thinning wood, waste wood, driftwood, and grass. , Wastes, dehydrated mud, and non-wood biomass fuels such as tires. In addition, the biomass fuel includes a pellet-shaped or chip-shaped recycled fuel using these as raw materials, and is not limited to those shown here.

The pulverized material supply pipe 7 is connected to the pulverizer 2, so that the pulverized fuel of the biomass fuel pulverized in the pulverizer 2 passes through the pulverized material supply pipe 7 together with heated air serving as a conveyance gas, It is guided to the burner 9 provided in (4).

A flame is formed in the furnace in the boiler body 4 by the burner 9, and steam is generated by a heat exchanger (not shown) in the boiler body 4. The generated steam is guided to a steam turbine (not shown) to rotate and drive the steam turbine. When the steam turbine is driven to rotate, a generator (not shown) coupled to the rotating shaft of the steam turbine rotates, and power generation is performed.

Next, the crusher 2 will be described.

The housing 11 constituting the outer shell of the pulverizer 2 has a male substantially cylindrical hollow shape, and a fuel supply pipe 13 is attached to the central portion of the ceiling 12. This fuel supply pipe 13 is a biomass fuel in which a predetermined amount of coal guided from the solid fuel supply device 3 is mixed (hereinafter referred to as "coal mixed biomass fuel". A method of mixing coal will be described later). Is supplied into the housing 11, and is arranged in the vertical direction (vertical direction) at the center position of the housing 11, and the lower end extends to the inside of the housing 11 and is provided.

A mount 14 is provided in the housing 11, and a grinding table 15 is arranged rotatably on the mount 14. The lower end of the fuel supply pipe 13 is disposed so as to face the center of the grinding table 15. The fuel supply pipe 13 supplies the coal-mixed biomass fuel from the upper side toward the lower pulverization table 15. The pulverizing table 15 is rotated about a central axis in the vertical direction (vertical direction) and is rotated by the drive device 10.

Above the grinding table 15, a plurality (for example, three) of grinding rollers 16 are arranged to face each other. Each crushing roller 16 is disposed above the outer circumferential portion of the crushing table 15 at equal intervals in the circumferential direction (In addition, only two crushing rollers 16 are disclosed in FIG. ]. When the grinding table 15 rotates with the outer circumferential surface in contact with the upper surface of the grinding table 15, the grinding roller 16 receives rotational force from the grinding table 15 and rotates together. When the coal-mixed biomass fuel is supplied from the fuel supply pipe 13, the coal-mixed biomass fuel is pressed between the pulverizing roller 16 and the pulverizing table 15 to be pulverized to become pulverized fuel.

A gas supply pipe 20 for conveyance is connected to the lower part of the housing 11. The conveying gas supplied by the conveying gas supply pipe 20 is guided in the housing 11 and supplied to a space located below the grinding table 15. The conveying gas is set to a high temperature for preheating and drying the conveyed solid fuel, and is set to, for example, about 120°C to 150°C. Therefore, the temperature of the space located below the grinding table 15 is about 120 to 150 degrees. The conveying gas in this embodiment uses air blown by, for example, a blower (not shown). Further, heated air supplied via a heat exchanger (heater) such as an air preheater (not shown) using the combustion gas of the boiler main body 4 as a heat source may be mixed to adjust the temperature of the conveying gas.

A rotary classifier 21 is provided on the upper part of the housing 11. The rotary classifier 21 is disposed so as to surround the fuel supply pipe 13, and rotates around the fuel supply pipe 13 by a driving force from a driving device (not shown). As the rotary classifier 21 rotates, a plurality of pins 22 mounted on the outer circumferential side thereof rotates in the circumferential direction. The pulverized material pulverized by the crushing table 15 and the crushing roller 16 is wound upward by the flow of the conveying gas rising along the outer circumferential side of the crushing table 15 from the bottom of the crushing table 15. It is raised. Among the rolled up pulverized products, a pulverized product having a relatively large diameter is knocked off by a pin 22, returned to the crushing table 15, and pulverized again. Thereby, the pulverized material is classified by the rotary classifier 21 to become pulverized fuel. Further, since the conveying gas is cooled by conveying the pulverized material while drying it in the housing 11, the temperature of the upper space of the housing 11 is, for example, about 60 degrees.

A plurality of pulverized material supply pipes 7 are connected to the ceiling 12. The pulverized material supply pipe 7 discharges the finely divided fuel classified by the rotary classifier 21, and guides the conveying gas obtained by mixing the discharged finely divided fuel to the burner 9 of the boiler body 4. The plurality of pulverized material supply pipes 7 are respectively connected to a plurality of openings provided corresponding to the ceiling 12. The number of pulverized material supply pipes 7 varies depending on the size and pulverization capacity of the pulverizer 2, but is in the range of approximately 2 to 8, and there are many cases of 4 to 6. In addition, in FIG. 1, only one is shown for the relationship of illustration.

The solid fuel supply device 3 includes a biomass fuel conveying device (biomass fuel conveying part) 23 that conveys biomass fuel stored in a silo (not shown) to a bunker (reserving part) 25, and a biomass fuel. Coal is mixed by a coal supplying device (coal mixing unit) 24 and a coal supplying device 24 for mixing a required amount of coal by spraying coal approximately uniformly with respect to the biomass fuel conveyed by the conveying device 23 A bunker 25 for storing the used coal-mixed biomass fuel, and a solid fuel feeder (supplying portion) 26 for supplying the coal-mixed biomass fuel introduced from the bunker 25 to the pulverizer 2 are provided. In addition, the solid fuel supply device 3 includes a downspout (reservoir) 27 directly connecting the lower end of the bunker 25 and the solid fuel supply 26, and air or inert gas in the solid fuel supply 26. A seal gas supply pipe 28 for supplying a seal gas such as a back is provided.

The biomass fuel conveying device 23 has a biomass fuel hopper 23a for temporarily storing biomass fuel from a silo and a first belt conveyor 23b. The biomass fuel conveying device 23 loads and conveys the biomass fuel from the biomass fuel hopper 23a on the first belt conveyor 23b. In addition, in the state being conveyed to the biomass fuel conveying device 23, the biomass fuel is in a pellet state because it is before pulverization. The size of the pellets is, for example, about 6 mm to 8 mm in diameter, and about 40 mm or less in length. Further, the supply amount for supplying the biomass fuel to the bunker 25 is adjusted to the belt speed of the first belt conveyor 23b.

The coal supply device 24 has a coal hopper 24a for temporarily storing coal and a second belt conveyor 24b, and the downstream end of the second belt conveyor 24b is, for example, a first belt conveyor ( It is arranged to be located above 23b). The coal supply device 24 adjusts the supply flow rate of the coal fuel at the belt speed of the second belt conveyor 24b that loads and conveys the coal from the coal hopper 24a on the second belt conveyor 24b. Then, coal is dropped downward from the downstream end of the second belt conveyor 24b, and coal is sprayed substantially uniformly on the biomass fuel loaded on the first belt conveyor 23b. In the coal supply device 24, the mixing ratio of coal in the coal-mixed biomass fuel stored in the bunker 25 is, for example, 4% by weight or more and 50% by weight or less, more preferably 5% by weight or more and 10 Coal is mixed so that it is not more than weight percent.

In addition, the particle diameter of the coal in the state supplied from the coal supply device 24 (that is, coal before pulverization) is, for example, about 7 mm to 8 mm in the 80% passage particle diameter. In addition, the mixing ratio of coal in the coal-mixed biomass fuel may be appropriately adjusted depending on the properties and conditions of the biomass fuel or coal, the particle size, etc., for example, a suitable value of 50% by weight or less. The same effect can be obtained by setting it as the range of.

In biomass fuel, even if it is pulverized into coarse pulverized fuel compared to coal, combustibility in the burner 9 of the boiler body 4 can be secured. On the other hand, the coal to be mixed is a configuration suitable for the treatment of biomass fuel in the pulverizer 2 (for example, the shape of the housing 11, the rotational speed of the crushing table 15, the rotational speed of the rotary classifier 21, etc.) In this case, coal having different properties from the biomass fuel cannot be properly treated, and it is supplied to the burner 9 as a pulverized fuel in a granulated state, thereby reducing the combustion performance. For this reason, it is preferable to set an upper limit for increasing the mixing ratio of the coal fuel to the biomass fuel.

The bunker 25 is disposed substantially vertically below the downstream end of the first belt conveyor 23b. The bunker 25 is formed, for example, in a substantially cylindrical shape, and has an inclined surface to reduce its diameter from the vicinity of the substantially center in the vertical direction. The upper end of the downspout 27 is connected to the lower end of the bunker 25.

The solid fuel feeder 26 has a case 26a constituting the outer shell and a third belt conveyor 26b disposed inside the case 26a. The down spout 27 is connected to the upper surface of the case 26a, and the seal gas supply pipe 28 and the fuel supply pipe 13 are connected to the lower surface of the case 26a. The upstream end of the third belt conveyor 26b is disposed below the connection portion between the case 26a and the downspout 27, and the downstream end of the third belt conveyor 26b is provided with the case 26a and the fuel supply pipe. It is arranged above the connection part of (13).

The downspout 27 is a metal pipe extending in a straight line in the vertical direction (vertical direction), and coal-mixed biomass fuel is stacked therein. That is, the supply amount of the coal-mixed biomass fuel supplied to the bunker 25 from the biomass fuel transfer device 23 and the supply amount of the coal-mixed biomass fuel supplied into the pulverizer from the solid fuel supplier 26 are balanced. Thus, in the downspout 27, a coal-mixed biomass fuel is loaded. In addition, the downspout 27 directly connects the lower end of the bunker 25 and the solid fuel supply 26, and the downspout 27 is, for example, conveying gas and pulverized fuel from the inside of the pulverizer 2 There is no special device such as a rotary valve for suppressing the backflow caused by the pumping up. The size of the downspout 27 changes depending on the nature and state of the solid fuel supplied, the particle diameter, and the amount supplied, but for example, in the case of a diameter of about 600 mm, the length in the vertical direction is set to about 1 m to 5 m, For example, when the diameter is about 900 mm, the length in the vertical direction is set to about 2 m to 5 m.

The seal gas supply pipe 28 supplies a seal gas such as air supplied from a seal gas supply device (not shown) into the case 26a of the solid fuel supply device 26. Due to the sealing gas, the inside of the case 26a is at a higher pressure than the inside of the pulverizer 2. The seal gas fills the inside of the case 26a and circulates through the fuel supply pipe 13 into the inside of the pulverizer 2. Since the temperature of the sealing gas is about 30 degrees, in the normal operation of the crusher 2, the temperature inside the case 26a is about 30 degrees. For this reason, as will be described later, it is easy to detect the backflow caused by spraying of the gas for conveyance and the finely divided fuel by the temperature measuring device 34.

The operation of the pulverizer 2 and the boiler facility 1 according to the present embodiment for pulverizing biomass fuel will be described below.

The biomass fuel stored in the silo is conveyed to the biomass fuel hopper 23a by a conveying device (not shown), and is temporarily stored in the biomass fuel hopper 23a. The biomass fuel temporarily stored in the biomass fuel hopper 23a is transported to the bunker 25 in a required amount by the first belt conveyor 23b (biomass fuel conveyance step).

On the other hand, coal is conveyed to the coal hopper 24a by a conveying device (not shown) and temporarily stored in the coal hopper 24a. The required amount of coal temporarily stored in the coal hopper 24a is conveyed by the second belt conveyor 24b. The coal transferred by the second belt conveyor 24b falls on the first belt conveyor 23b from the downstream end of the second belt conveyor 24b, for example. Since the biomass fuel is conveyed in the first belt conveyor 23b, the coal-mixed biomass fuel is generated by spraying the biomass fuel substantially uniformly (coal mixing process). The coal-mixed biomass fuel falls into the bunker 25 from the downstream end of the first belt conveyor 23b. The coal-mixed biomass fuel that has fallen into the bunker 25 is stored while being loaded into the inside of the bunker 25 and the inside of the downspout 27.

The coal-mixed biomass fuel stored in the bunker 25 and in the downspout 27 is transported by a third belt conveyor 26b built in the solid fuel feeder 26, and the fuel supply pipe 13 Is sent to The coal-mixed biomass fuel supplied to the fuel supply pipe 13 falls toward the inside of the pulverizer 2. At this time, the pressure inside the case 26a of the solid fuel supplier 26 is determined by the seal gas supplied from the seal gas supply pipe 28 inside the solid fuel supplier 26. Pressure is higher. Accordingly, the coal-mixed biomass fuel preferably falls into the pulverizer 2.

The coal-mixed biomass fuel supplied into the pulverizer 2 falls on the crushing table 15, moves to the outer circumferential side by centrifugal force, and is pulverized between the plurality of crushing rollers 16 and the crushing table 15, It becomes a pulverized fuel. The pulverized product of the pulverized coal-mixed biomass fuel rises in the pulverizer 2 by the conveying gas blown into the pulverizer 2 through the conveying gas supply pipe 20.

In the upper part of the grinding table 15, a rotary classifier 21 consisting of a plurality of pins (wings) 22 is rotating, and the coarse and heavy ground material is knocked off so as to be bounced off by the centrifugal force of the pins 22. It is returned on the grinding table 15. The pulverized material is repeatedly pulverized in the pulverizing table 15 until the particle size becomes smaller than a predetermined diameter. The pulverized material having a small particle diameter passes through the rotary classifier 21 as pulverized fuel, is discharged from the pulverizer 2, and is conveyed to the outside through the pulverized material supply pipe 7. The conveying gas obtained by mixing the conveyed pulverized fuel is sent to the burner 9 of the boiler main body 4 for combustion.

According to this embodiment, the following effects are exhibited.

In this embodiment, coal is mixed with the biomass fuel conveyed to the bunker 25. Accordingly, the solid fuel stored in the bunker 25 and the downspout 27 becomes a coal-mixed biomass fuel in which biomass fuel and coal are mixed. Since coal has a smaller particle diameter than biomass fuel, in a coal-mixed biomass fuel, coal enters the gap formed between the biomass fuels. Thereby, since coal blocks the gap formed between the biomass fuels, it becomes difficult for the conveying gas and the pulverized fuel from the inside of the crusher 2 to pass through the bunker 25 and the downspout 27. Accordingly, it is possible to suppress the flow rate of the reverse flow due to spraying of the gas for conveyance and the pulverized fuel from the inside of the crusher 2 passing through the bunker 25 and the downspout 27. That is, the coal-mixed biomass fuel improves the sealability in the bunker 25 and the downspout 27 than only the biomass fuel in which coal is not mixed. Therefore, since the coal-mixed biomass fuel stored in the bunker 25 and the downspout 27 achieves the role of a sealing material, the pressure inside the pulverizer 2 can be preferably maintained. Thereby, the gas for conveyance mixed with the pulverized fuel is stabilized and is supplied to the burner 9 of the boiler body 4 via the pulverized material supply pipe 7.

Further, by mixing coal having a particle diameter smaller than that of biomass fuel, the surface area of the entire solid fuel stored in the bunker 25 and downspout 27 increases. Since the gas for conveyance and the pulverized fuel from the inside of the crusher 2 going to pass through the bunker 25 and the downspout 27 circulate while in contact with the surface of the solid fuel, they are passed through the bunker 25 and the downspout 27. When the total surface area of the stored solid fuel increases, the pressure loss when the gas for conveyance and the finely divided fuel pass through the gap between the stored solid fuel increases. This makes it difficult for the conveying gas and the pulverized fuel to pass through the bunker 25 and the downspout 27, and thus the conveying gas from the inside of the crusher 2 passing through the bunker 25 and downspout 27 It is possible to suppress the flow rate of reverse flow due to the spraying of the and finely divided fuel. Therefore, the pressure inside the crusher 2 can be preferably maintained. Thereby, the gas for conveyance mixed with the pulverized fuel is stabilized and is supplied to the burner 9 of the boiler body 4 via the pulverized material supply pipe 7.

In addition, a special device for suppressing the flow rate of reverse flow due to spraying of gas and pulverized fuel from the inside of the crusher 2 passing through the bunker 25 and the downspout 27 to the downspout 27, etc. Since it is not necessary to provide (for example, a rotary valve, etc.), it is possible to suppress an increase in installation cost and suppress a decrease in operability as compared to a case where an apparatus or the like is provided.

In addition, according to the present embodiment, by suppressing the flow rate of the reverse flow due to spraying of the gas for conveyance and the pulverized fuel from the inside of the crusher 2 passing through the bunker 25 and the downspout 27, the crusher (2) It is possible to maintain the internal pressure preferably. Thereby, the supply of the coal biomass fuel supplied to the pulverizer 2 can be stabilized, and the solid fuel can be preferably treated with the pulverizer 2. Accordingly, the properties and conditions of the pulverized fuel supplied to the boiler body 4 can be appropriately adjusted, and the energy efficiency of the entire boiler facility 1 can be improved.

In addition, when the mixing ratio of the coal to be mixed is small, coal does not sufficiently enter the gap formed between the respective biomass fuels stored in the bunker 25 and the downspout 27. As a result, there is a possibility that the gas for conveyance and the pulverized fuel from the inside of the grinder 2 pass through the gap, so that the pressure inside the grinder 2 cannot be preferably maintained.

On the other hand, if the mixing ratio of the coal to be mixed is large, there is a possibility that the coal cannot be properly treated in the crusher 2. Specifically, since coal is not particularly high in combustibility, it is necessary to pulverize it smaller than biomass fuel and supply it to the burner 9, but the pulverizer 2 has a configuration suitable for processing biomass fuel (for example, a housing shape , The rotation speed of the crushing table 15 or the rotation speed of the rotary classifier 21), so that the coal contained in the coal-mixed biomass fuel is pulverized to the size required as the pulverized fuel of the coal. Includes those that are not assembled. When the pulverized pulverized fuel is mixed with coarse coal and supplied to the burner 9, combustibility with respect to the burner 9 may decrease and unburned coal fine powder may increase. If unburned coal fines increase in the burner 9, ashes accumulate in the furnace bottom of the boiler body 4, and the environmental properties are likely to decrease due to an increase in CO generation or an increase in NOx. There is this.

In the present embodiment, the mixing ratio of coal to be mixed is, for example, 4% by weight or more and 50% by weight or less, and more preferably 5% by weight or more and 10% by weight or less. Thereby, while maintaining the pressure inside the pulverizer suitably, it is also possible to prevent deterioration of the flammability in the boiler body 4. In addition, the mixing ratio of coal in the coal-mixed biomass fuel may be appropriately adjusted according to the properties and conditions of the biomass fuel or coal, the particle size, etc., for example, in a range of 50% by weight or less. Thus, the same effect can be obtained.

Here, the relationship between the sealing property improvement effect of the coal-mixed biomass fuel and the combustibility in the boiler main body 4 is demonstrated with reference to FIG.

In Fig. 2, the relationship between the mixing ratio of coal and the sealability (indicated by the solid line in the drawing) and the relationship between the mixing ratio of coal and the combustibility (indicated by the dashed-dotted line in the drawing) are shown. In addition, about the relationship between the mixing ratio of coal and the sealing property, the case of 100% of coal is shown as 1.0. About the relationship between the mixing ratio of coal and the combustibility, the case of 100% of biomass fuel is shown as 1.0.

As is clear from FIG. 2, the sealability with respect to the mixing ratio of coal improves as the mixing ratio of coal to biomass fuel increases. In addition, it can be seen that when the mixing ratio of coal is from 0% by weight to about 10% by weight, the sealing property is rapidly improved, and when the mixing ratio of coal is about 50% by weight or more, it is saturated (see Fig. 5 to be described later). Further, it can be seen that the combustibility with respect to the mixing ratio of coal decreases as the mixing ratio of coal to the biomass fuel increases. As described above, since the combustibility is adjusted by a configuration suitable for the treatment of biomass fuel (for example, the shape of the housing, the rotational speed of the crushing table 15, the rotational speed of the rotary classifier 21, etc.), coal If the mixing ratio of is too high, coarse coal is mixed with the pulverized fuel and supplied to the burner 9, so that the combustibility in the burner 9 decreases.

From this, when the mixing ratio of coal is, for example, between 4% by weight and 50% by weight, the sealability is at a high level without significantly lowering the combustibility, more preferably from 5% by weight to 10% by weight. It can be seen that the sealability and combustibility are at a high level together.

The invention of the present invention has been made based on the knowledge that the sealing property is greatly improved even when the mixing ratio of coal is low by weight.

It is also understood from the following that the sealing property is greatly improved even when the mixing ratio of coal is low by weight. Hereinafter, it will be described with reference to FIGS. 3 to 5.

In the present invention, with only biomass fuels (particles of large particle diameter), the gap [porosity (空孔率) ε] formed between each biomass fuel is large, but by adding coal (particles of small particle diameter) Was found to be able to rapidly improve the sealability by lowering.

Grains of biomass fuel (particles of large particle diameter) and coal (particles of small particle diameter) are simulated to be spherical, and there is a situation in which a large number of voids are generated in biomass fuel (particles of large particle diameter). Therefore, it is arranged in an orderly manner. The porosity (ε) is when n particles of the particle diameter (D) are aligned vertically and horizontally (see Fig. 3). In Fig. 3, the following formula (1) shows the case where three particles having a particle diameter (D) are arranged vertically and horizontally, for example.

ε=1-[[(π/4)×D ² ×n×n]/(D×n×D×n)]...(1)

That is, the porosity (ε) is represented by the following formula (2).

1-(π/4)...(2)

That is, in the case of orderly alignment, the porosity (ε) becomes constant at about 21.5% regardless of the size of the particle diameter.

However, for a state in which particles of large particle diameter [particle diameter (D)] (biomass fuel in this embodiment) are arranged in an order (hereinafter referred to as "order arrangement state"), particles of small particle diameter [particle diameter (d)] By mixing the dense arrangement state of (coal in this embodiment) (see Fig. 4. In Fig. 4, for example, 7 small particle diameter particles are arranged in a dense arrangement) (ε) becomes smaller. In addition, here, the mixing of the particles of the large particle diameter with the particles of the large particle diameter is simulated by changing one or more of a part of the particles of the large particle diameter in the ordered arrangement state to the particles of the small particle diameter in the dense arrangement state. As an example, it shows, for example, changing one or a plurality of particles of particles having a large particle diameter into particles having a small particle diameter in a densely arranged state.

The pressure loss (Δp/L) per unit length of the fluid flowing through the solid particle packed bed is represented by the following equation (3) from the Kozeny Carman equation.

Δp/L=K×V×μ×Sv ² ×(1-ε) ² /ε ³ ···(3)

However, K: Cozeny coefficient

V: empty tower speed

μ: viscosity of the fluid

ε: porosity

Sv: surface area per unit volume of particle

Since the leakage flow rate is proportional to the empty column velocity obtained from the Kogeny Kalman equation, the sealing property can be evaluated by a flow rate ratio capable of suppressing leakage. Therefore, the sealing property can be represented by the following formula (4).

[(Leakage flow rate in the standard state)-(Leakage flow rate in the state where the sealing rate is derived)]/(Leakage flow rate in the standard state)...(4)

The graph of Fig. 5 shows the relationship between the small particle rate and the sealing property.

In addition, in FIG. 5, the sealing property is represented by the following formula (5) in accordance with the above-described formula 4.

[Maximum leakage flow rate (Ca=0%)-leakage flow rate (Ca=X%)]/maximum leakage flow rate (Ca=0%)...(5)

However, Ca: small particle ratio (the ratio of the small particles in the densely arranged state to the sum of the large particles and the small particles in the densely arranged state. For example, when one of the particles of the large particle diameter in FIG. 3 becomes the smallest particles in the densely arranged state) In the example of, the elementary particle rate is 1/9, which is about 11%)

In addition, the leakage flow rate Q is represented by the following formula (6).

Q=K×V=K/(Δp/L)...(6)

However, K: Cozeny coefficient

V: empty tower speed

As is clear from the graph of Fig. 5, it can be seen that the sealing property is rapidly improved at a value having a low small particle rate. This is due to the fact that by mixing the small particles, the surface area (Sv) increases rapidly, and the pressure loss (Δp/L) increases.

In addition, from the graph of FIG. 5, it is estimated that the sealing property is about 0.5 when the mixing ratio of coal is, for example, 4% by weight, and the leakage flow rate is halved to greatly improve leakage, and the mixing ratio of coal is an example. For example, in the case of 50% by weight or more, it is presumed that the sealability is saturated to about 1.0, and the leakage flow rate almost disappears. In addition, in consideration of the combustibility shown in FIG. 2 described above, it is not desirable to significantly increase the mixing ratio of coal, so it can be considered that the mixing ratio of coal is preferably from 4% by weight to 50% by weight in terms of sealing properties.

In addition, if the mixing ratio of coal is, for example, 5% by weight, the sealability becomes about 0.6, and the leakage flow rate decreases to about 40%, so that most of the problems caused by leakage are eliminated. For example, at 10% by weight or more, the sealability becomes about 0.8, and it is presumed that there is sufficient sealability. For this reason, between 5% by weight and 10% by weight, the sealability is sufficiently high, and the sealability and combustibility, including the combustibility shown in Fig. 2, are at a high level, and it can be considered that it is preferable.

Therefore, from the above equations and graphs, by mixing a small amount of small particle diameter particles (coal in this embodiment) with large particle diameter particles (biomass fuel in this embodiment), the sealing property is rapidly improved. Can be seen.

[Second Embodiment]

Subsequently, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. The solid fuel supply device 33 according to the present embodiment is different from the first embodiment in that it includes a temperature measuring device 34 and a control device 35. In addition, the same reference numerals are assigned to the same parts as those in the first embodiment, and detailed descriptions thereof are omitted.

As shown in FIG. 6, the temperature measuring device 34 is provided in the interior of the solid fuel supply 26, for example, above the connection portion between the solid fuel supply 26 and the fuel supply pipe 13. . That is, the temperature measuring device 34 is provided near the upper end of the fuel supply pipe 13. The temperature measuring device 34 measures the temperature inside the case 26a of the solid fuel supply device 26 and transmits the measured temperature to the control device 35.

The control device 35 controls the coal supply device 24 based on the temperature measured by the temperature measuring device 34 to adjust the mixing ratio of coal to be mixed with the biomass fuel. Specifically, the belt speed of the second belt conveyor 24b of the coal supply device 24 is adjusted to adjust the amount of coal sprinkled on the biomass fuel.

The control device 35 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. The series of processing for realizing various functions is, as an example, stored in a storage medium or the like in the form of a program, the CPU reads this program into RAM, etc., and executes the processing and calculation processing of information, Various functions are realized. In addition, the program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or transmitted through a wired or wireless communication means. . The computer-readable storage medium is a magnetic disk, an optical magnetic disk, a CD-ROM, a DVD-ROM, and a semiconductor memory.

Next, the mixing ratio changing process executed by the control device 35 of the present embodiment will be described using a flow chart in FIG. 7.

First, the control device 35 acquires the internal temperature of the solid fuel supply 26 measured by the temperature measuring device 34 (S1). Next, it is determined whether or not the acquired temperature is equal to or higher than a predetermined temperature (S2). When the acquired temperature is more than a predetermined temperature (for example, 50 degrees), the process proceeds to S3. When the acquired temperature is not more than the predetermined temperature, it returns to S1.

In S3, it is judged that a reverse flow has occurred due to spraying of the gas for conveyance inside the crusher 2 and the pulverized fuel, and the belt speed of the second belt conveyor 24b of the coal supply device 24 is increased, and the coal The mixing ratio of is increased from the predetermined weight %. Here, for example, it is increased by 1% by weight. If the mixing ratio of coal is increased by 1% by weight, it proceeds to S4. In S4, the temperature inside the solid fuel supply device 26 measured by the temperature measuring device 34 is acquired, and it is determined whether or not the increase in temperature is stopped. In addition, the determination of S4 may be performed after a predetermined time has elapsed by increasing the mixing ratio of coal by 1% by weight in S3. When the temperature increase is stopped, it proceeds to S5. When the temperature increase is not stopped, it shifts to S3, and the mixing ratio of coal is further increased, for example, by 1% by weight again.

In S5, it is operated for a while without increasing the mixing amount of coal, and after a predetermined time elapses, the mixing ratio of coal is gradually decreased, for example, by 1% by weight, to a predetermined mixing ratio, which is a predetermined weight%. Return. When the mixing ratio of coal is returned to the predetermined mixing ratio, it shifts to S1.

In addition, the above control is an example, and numerical values and the like may be appropriately changed. For example, the predetermined temperature for increasing the mixing ratio of coal is not limited to 50 degrees, and is a temperature based on the temperature of the conveying gas that is pumped up from the inside of the crusher 2 and flows back. Any temperature that can detect what is there is good. Further, the ratio of increasing the mixing ratio of coal is also not limited to 1% by weight. It may be more than 1% by weight, and at least more than 1% by weight.

According to this embodiment, the following effects are exhibited.

In this embodiment, the solid fuel feeder 26 in which the temperature measuring instrument 34 measures the temperature is provided between the downspout 27 and the crusher 2. As a result, when the conveying gas and the pulverized fuel in the pulverizer 2 pass through the downspout 27, the solid fuel feeder 26 is circulated.

When operating normally, the temperature in the solid fuel supply unit 26 becomes substantially the same as the temperature of the sealing gas, and is, for example, about 30 degrees. On the other hand, since the high temperature conveyance gas is supplied into the grinder 2, the temperature of the conveyance gas in the grinder 2 is increasing. The temperature in the pulverizer 2 is, for example, about 60 degrees even in the upper space of the pulverizer 2 away from the connection portion of the conveying gas supply pipe 20. Therefore, when the gas for conveyance and the pulverized fuel in the pulverizer 2 flow through the solid fuel feeder 26, the temperature in the solid fuel feeder 26 rises.

In the present embodiment, the temperature measuring device 34 measures the temperature in the solid fuel supplier 26 to determine whether or not the temperature in the solid fuel supplier 26 is, for example, 50 degrees or more. Thereby, when the temperature inside the solid fuel supply 26 rises and becomes 50 degrees or more, the conveyance gas and the pulverized fuel in the pulverizer 2 are blown up inside the fuel supply pipe 13 and flow back, and the solid It can be determined that it flows into the fuel supply 26 and passes through the downspout 27 and the bunker 25. Accordingly, it is possible to reliably detect whether or not the conveying gas and the pulverized fuel in the crusher 2 pass through the downspout 27 and the bunker 25 by a simple and easy method.

In addition, in this embodiment, when it is determined that the conveying gas and the pulverized fuel in the crusher 2 are passing through the downspout 27 and the bunker 25, the mixing ratio of coal is increased from the predetermined mixing ratio. , Has been decreasing since then. Thereby, the mixing ratio of the gas for conveyance passing through the downspout 27 and the bunker 25 and the coal according to the flow rate of the countercurrent due to the blowing up of the pulverized fuel can be determined, so that the transport in the crusher 2 can be reliably used. It is possible to prevent gas and pulverized fuel from passing through the downspout 27 and the bunker 25, and at the same time, excessively increasing the mixing ratio of coal, leading to a deterioration of the combustion state in the boiler body 4 Can be prevented.

In addition, since the solid fuel feeder 26 is provided between the downspout 27 and the crusher 2, the temperature measuring instrument 34 measures the temperature in the relative vicinity of the crusher 2. As a result, since the conveying gas is not greatly cooled in other structures or the like, it can be measured and detected with the temperature measuring instrument 34 at a relatively high temperature. Accordingly, when the temperature measuring device 34 measures the temperature, it is difficult to be affected by other environments such as seal gas supplied into the solid fuel supply device 26, for example. Accordingly, it is possible to accurately determine whether or not reverse flow due to the pumping of the gas for conveyance and the pulverized fuel in the pulverizer 2 through the downspout 27 and the bunker 25 is passing through.

In addition, the present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified within a range not departing from the gist thereof.

For example, in each of the above embodiments, biomass fuel and coal are mixed by sprinkling coal on the biomass fuel conveyed on the first belt conveyor 23b of the biomass fuel conveying device 23. Alternatively, the coal conveyed by the second belt conveyor 24b of the coal supply device 24 may be mixed by spraying biomass fuel. Alternatively, you may mix by supplying biomass fuel and coal to the bunker 25 directly from the biomass fuel conveying device 23 and the coal supply device 24.

In addition, in each of the above embodiments, an example in which a solid fuel supply device is provided in the boiler facility 1 has been described, but the solid fuel supply device is a combustion device such as an Integrated Coal Gasification Combined Cycle (IGCC). You may fuel it.

1: boiler equipment (combustion equipment) 2: grinder
3: solid fuel supply device 4: boiler body (combustion part)
7: pulverized material supply pipe 9: burner
11: housing 13: fuel supply pipe
15: grinding table 16: grinding roller
20: gas supply pipe for conveyance 21: rotary classifier
22: pin
23: biomass fuel transfer device (biomass fuel transfer unit)
24: coal supply device (coal mixing unit) 25: bunker (reservoir)
26: solid fuel supply unit (supplying unit) 27: downspout (reserving unit)
28: seal gas supply pipe 34: temperature measuring instrument
35: control device

Claims (5)

In a solid fuel supply device for supplying biomass fuel and coal as the solid fuel to a pulverizer for supplying pulverized fuel obtained by pulverizing solid fuel to a boiler,
A storage unit for storing the solid fuel supplied to the inside of the pulverizer,
A biomass fuel transfer unit for transferring the biomass fuel to the storage unit,
A coal mixing unit for mixing the coal with the biomass fuel conveyed to the storage unit,
The coal mixing unit mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 4% by weight or more and 50% by weight or less,
A supply unit provided between the storage unit and the pulverizer and supplying the solid fuel stored in the storage unit to the pulverizer,
It has a temperature measuring instrument for measuring the temperature in the supply,
The coal mixing unit changes the mixing ratio of the coal based on the temperature measured by the temperature measuring instrument.
Solid fuel supply. The method of claim 1,
The coal mixing unit mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 5% by weight or more and 10% by weight or less.
Solid fuel supply. delete The solid fuel supply device according to claim 1 or 2, and
A grinder for pulverizing the solid fuel supplied by the solid fuel supply device,
Comprising a combustion unit to which the solid fuel pulverized with the grinder is supplied
Combustion equipment. In a method of operating a solid fuel supply device for supplying biomass fuel and coal as the solid fuel to a pulverizer that supplies pulverized fuel obtained by pulverizing solid fuel to a boiler,
The solid fuel supply device includes a storage unit for storing the solid fuel supplied to the inside of the pulverizer,
A biomass fuel conveying step of conveying the biomass fuel to the reservoir,
A coal mixing process of mixing the coal with the biomass fuel conveyed to the storage unit,
In the coal mixing step, the coal is mixed so that the mixing ratio of the coal in the solid fuel stored in the reservoir is 4% by weight or more and 50% by weight or less,
The solid fuel supply device,
A supply unit provided between the storage unit and the pulverizer and supplying the solid fuel stored in the storage unit to the pulverizer,
It has a temperature measuring instrument for measuring the temperature in the supply,
Based on the temperature measured by the temperature meter, changing the mixing ratio of the coal
How to operate a solid fuel supply.

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