CN214249564U

CN214249564U - Composite combustion circulating fluidized bed

Info

Publication number: CN214249564U
Application number: CN202023265707.5U
Authority: CN
Inventors: 郭汉荣
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-09-21
Anticipated expiration: 2030-12-30

Abstract

The utility model discloses a composite combustion circulating fluidized bed, which comprises an automatic control electric cabinet, a crusher, a hearth of the fluidized bed, a chimney, a flue connecting the chimney and the hearth, a hot air pipe, a powder pipe and a gas-powder mixing structure; the powder pipe comprises a main powder pipe and a powder dividing pipe, and the main powder pipe is connected with the pulverizer and the powder dividing pipe; one hot air pipe is communicated with the pulverizer and the flue, and the other two hot air pipes are used for connecting the flue and the gas-powder mixing structure together; the gas-powder mixing structure mixes the powder conveyed by the powder dividing pipe and the high-temperature flue gas conveyed by the hot air pipe and then sprays the mixture to two sides of the hearth; the flue is communicated with the chimney through an induced draft fan, the chimney is provided with an oxygen meter for detecting the oxygen content in the discharged waste gas, and the hearth is also provided with a steam pressure gauge for detecting the steam pressure; the automatic control electric cabinet is respectively connected with the pulverizer, the gas-powder mixing structure, the draught fan, the steam pressure meter and the oxygen meter. The utility model has the advantages of high combustion intensity, fast temperature rising speed and high thermal efficiency.

Description

Composite combustion circulating fluidized bed

Technical Field

The utility model belongs to the technical field of the composite combustion technique and specifically relates to a composite combustion circulating fluidized bed.

Background

At present, the combustion mode of an industrial boiler basically comprises the following modes:

1. the solid-phase combustion mode mainly adopts a reciprocating furnace of a chain furnace, the heat efficiency is the lowest in the use of industrial boilers, and the national standard only requires 75 percent of heat power.

2. The other is a circulating fluidized bed, belongs to fluidized combustion, and has better thermal efficiency which can reach more than 80 percent.

3. The last one is powder combustion, which is homogeneous combustion and is the most efficient combustion mode at present, and the thermal power is more than 90%.

In contrast, the biomass gasification furnace developed in more than 10 years, namely gasification combustion, has thermal power of only about 50%, generates a lot of tar to be treated and generates nitrogen oxide waste gas exceeding the emission standard.

Therefore, improvements to the prior art are yet to be made.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a compound combustion circulating fluidized bed aims at solving the gasification combustion mode heat power of current industrial boiler and hangs down to and exhaust emission technical problem not up to standard.

In order to achieve the above purpose, the technical scheme of the utility model is as follows: a composite combustion circulating fluidized bed comprises an automatic control electric cabinet, a pulverizer, a hearth of the fluidized bed, a chimney, a flue for connecting the chimney and the hearth, a hot air pipe, a powder pipe and a gas-powder mixed structure; the powder pipe comprises a main powder pipe and a powder dividing pipe, and the main powder pipe is connected with the pulverizer and the powder dividing pipe; one hot air pipe is communicated with the pulverizer and the flue, and the other two hot air pipes are used for connecting the flue and the gas-powder mixing structure together; the gas-powder mixing structure mixes the powder conveyed by the powder dividing pipe and the high-temperature flue gas conveyed by the hot air pipe and then sprays the mixture to two sides of the hearth; the flue is communicated with the chimney through an induced draft fan, the chimney is provided with an oxygen meter for detecting the oxygen content in the discharged waste gas, and the hearth is also provided with a steam pressure gauge for detecting the steam pressure in the hearth; the automatic control electric cabinet is respectively connected with the pulverizer, the gas-powder mixing structure, the draught fan, the steam pressure meter and the oxygen meter.

The composite combustion circulating fluidized bed, wherein, the gas powder mixed structure sprays the gas powder after mixing to the both sides of furnace through the injection gun, and this gas powder mixed structure includes high-pressure high temperature blower and hybrid tube, the upper end of hybrid tube respectively with the hot-blast main with divide the powder union coupling, high-pressure high temperature blower installs the bottom at the hybrid tube, and the hot-blast main passes through the internal air duct of hybrid tube and is connected with high-pressure high temperature blower, the powder mouth department of air outlet in the hybrid tube of high-pressure high temperature blower, so mix the powder high temperature flue gas and spray in the injection gun again.

The composite combustion circulating fluidized bed is characterized in that the high-pressure high-temperature fan is connected with a power control electric cabinet.

The composite combustion circulating fluidized bed is characterized in that the hearth is also connected with a boiler blower for increasing the air quantity in the hearth.

The composite combustion circulating fluidized bed is characterized in that the mixing cylinder sprays mixed gas powder to the flame center in the hearth from one side of the hearth through the spray gun, and the mixing cylinder sprays the mixed gas powder to the flame center in the hearth from the other side of the hearth through the spray gun.

The combined combustion circulating fluidized bed, wherein, furnace still is connected with boiler blanking machine, whether boiler blanking machine carries out the blanking by motor control, the motor is connected with the automatic control electric cabinet.

The combined combustion circulating fluidized bed is characterized in that the boiler blanking machine is arranged below the coal hopper.

The composite combustion circulating fluidized bed is characterized in that the pulverizer is controlled by an automatic control electric cabinet.

The combined combustion circulating fluidized bed, wherein, rubbing crusher is connected with the blanking machine, the blanking machine is smashed for rubbing crusher by automatic control electric cabinet control blanking, the blanking machine is located the below of coal funnel.

The composite combustion circulating fluidized bed is characterized in that the blanking machine is a spiral feeder.

Has the advantages that: the utility model discloses a combined combustion circulating fluidized bed mainly is to send into 5~20% fuel into the furnace burning through gas-powder mixed structure with likepowder form, and the heat that the circulating fluidized bed upper segment released can make it catch fire rapidly and release a large amount of heat, can turn over again and burn the large granule fuel on the circulating fluidized bed to improve its combustion efficiency, reduce fuel consumption. The combustion efficiency of the powdery fuel is high, the coefficient of excess air in the furnace can be reduced, the hot flue gas powder feeding characteristic is similar to that of flue gas circulation, the oxygen concentration in a combustion area can also be diluted, and the superposition of the flue gas circulation and the hot flue gas powder feeding characteristic can effectively inhibit the generation of NOx, so the powdery fuel has the advantages of high combustion intensity, high temperature rise speed, high thermal efficiency and the like.

Drawings

Fig. 1 is a plan view of the present invention.

Fig. 2 is a schematic view of a first embodiment of the gas-powder mixing structure of the present invention.

Fig. 3 is a schematic view of a second embodiment of the gas-powder mixing structure of the present invention.

Fig. 4 is another schematic diagram of the present invention.

Fig. 5 is a schematic view of the furnace installation structure of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention will be described in further detail below with reference to the accompanying drawings and examples.

As shown in fig. 1, the utility model discloses a composite combustion circulating fluidized bed, which comprises an automatic control electric cabinet 8, a pulverizer 1, a hearth 9 of the fluidized bed, a chimney 10, a flue 11 connecting the chimney 10 and the hearth 9, a hot air pipe 2, a powder pipe 3 and a gas-powder mixing structure 100; the powder pipe 3 comprises a main powder pipe 3a and a powder dividing pipe, and the main powder pipe is connected with the pulverizer 1 and the powder dividing pipe; the gas-powder mixing structure 100 sprays the mixed gas powder to two sides of the hearth 9 through the spray guns 6-1 and 6-2, the gas-powder mixing structure 100 comprises a high-pressure high-temperature fan 5 and a mixing barrel 4, the high-pressure high-temperature fan 5 sprays the gas powder mixed by the mixing barrel 4 to two sides of the hearth 9 and aims at the flame center in the hearth to spray the gas powder, and the effect of immediate ignition and combustion is achieved; the hot air pipe 2 comprises a first hot air pipe 7, a second hot air pipe 7-1 and a third hot air pipe 7-2, the first hot air pipe 7 is communicated with the pulverizer 1 and the flue, and the mixing cylinder 4 is respectively connected with one end of the powder dividing pipe 3-1 and one end of the second hot air pipe 7-1; the mixing cylinder 4 is respectively connected with one end of the powder dividing pipe 3-2 and one end of the hot air pipe III 7-2; the other ends of the second hot air pipe 7-1 and the third hot air pipe 7-2 are connected with a flue 11; the flue 11 is communicated with a chimney 10 through an induced draft fan 12, the chimney 9 is provided with an oxygen meter 13 for detecting oxygen content in discharged waste gas, and the hearth 9 is also provided with a steam pressure gauge 14 for detecting steam pressure in the hearth; the automatic control electric cabinet 8 is respectively connected with the pulverizer 1, the high-pressure high-temperature fan 5, the induced draft fan 12, the steam pressure gauge 14 and the oxygen gauge 13.

After the structure of the oil adding device is adopted, the utility model discloses a high temperature flue gas in the hot-blast main with the flue is drawn to the rubbing crusher and is carried out dry and pyrolysis to fuel powder, makes fuel powder touch flame and catches fire promptly, has reduced the step that cold fuel powder got into just drying in the stove, pyrolysis, for example: when the fuel is coal, the coal powder can be dried and pyrolyzed by smoke gas at 500 ℃ through 300-; this technique comes from the principle of thermochemical reaction of substances: before coal (carbon) and oxygen are combined into carbon dioxide (heat release), the coal (carbon) and the oxygen respectively have to break the chemical bond (heat absorption) process of molecules, and because the reaction time before the heat release is reduced in advance, the powder can be ignited once reaching the furnace, and the combustion effect is particularly good. Especially, when the oxygen content of the high-temperature flue gas is below 15% (normal air is 21%), the same amount of gas (same cubic amount) required by the boiler during working enters the hearth, the oxygen content of the flue gas is obviously about 30% less than that of the air. Since a part of the nitrogen oxide (N0x) contained in the fuel is first changed to a gaseous compound when the fuel droplets or particles are heated, it is an intermediate product before N0x is formed, and mainly exists in the form of HCN (cyanic acid), NH3 (ammonia gas), or the like. Considering that the content (or the excess air coefficient) of oxygen (O2) has important influence on the generation of N0x (nitrogen oxide), on the premise of ensuring the stable combustion of the coal dust, the coal dust is combusted by high-temperature low-oxygen air, and the effect and the mechanism of the coal dust for greatly reducing the NOx under the low-oxygen combustion environment are searched. Therefore, nitrogen (the chemical bond energy is more than one time larger than that of carbon) in the hearth has no chance to search redundant oxygen molecules to combine to generate nitrogen oxide, so that the nitrogen oxide is reduced.

Nitrogen is more difficult to combine with other gases such as carbon, hydrogen, sulfur, etc. because of its greater chemical bond energy than others. However, in the operation process of the current industrial boiler, most furnaces are in a state of local high temperature (large temperature difference of cold and hot in the furnace) during combustion and the phenomenon of large excess air coefficient (excessive air quantity and excessive oxygen/carbon/matching ratio) of the furnaces due to various reasons, so that nitrogen oxides (N0x) generally discharged by flue gas are more than 150mg/m3 and exceed national emission standards. Two major reasons of local high temperature (actually not real high temperature) and large excess air coefficient (too much oxygen) are direct factors causing excessive emission of a large amount of nitrogen oxides (N0x) in the combustion process of a hearth.

Has the following advantages: 1. the combustion intensity of the hearth is enhanced, and the flame fullness is better; 2. the excess air amount is obviously reduced, the temperature of the hearth is obviously improved, and the heat efficiency is improved; 3. the Nox emission meets the requirement and reaches about 10Omg/m 3; the high-temperature low oxygen directly reduces the discharge of harmful substances and gases in the flue gas by more than 50 percent, and the discharge of nitrogen oxides is greatly reduced, thereby completely reaching the national discharge standard.

The intracranial combustion of a common circulating fluidized bed is blown and combusted by a bottom blower, but large-particle fuel (such as large-particle coal) is heated unevenly when being combusted, and the oxygen content in a hearth is high after the blowing of the blower, so that nitrogen in the hearth can acquire oxygen to form nitrogen oxide.

The mixed gas powder is sprayed to the two sides of the hearth through the spray gun by the gas-powder mixing structure, and the fuel powder and the flue gas are sprayed into the hearth after being mixed and are contacted with flame, so that the fuel powder can be instantly ignited; the whole space in the hearth is stirred to form thermal diffusion, the furnace temperature is quickly increased, the fuel is quickly burnt through, so that the fuel in the hearth is combusted, the thermal diffusion can press the number of blast of an air blower, the oxygen content in the hearth is reduced, the smoke stays in the furnace for a long time, and the emission of all waste gas and dust is reduced; meanwhile, oxygen in the hearth is consumed, so that the oxygen content of the flue gas is reduced. The utility model discloses owing to restrained the blast volume of air-blower, when having reduced the interior oxygen content of stove, guaranteed again that the fuel is by the homogeneous combustion, improved original blast air burning fuel because fuel need absorb heat when burning, lead to combustion temperature inhomogeneous, easy and too much oxygen formation nitrogen oxide's problem. The utility model discloses because improve the furnace temperature fast, so carbon/oxygen molecule chemical bond can open fast, forms carbon dioxide in the twinkling of an eye.

Because the oxygen content of the flue gas discharged by the existing circulating fluidized bed is about 13-17% and the distance is 10%, the flue gas rapidly burns in a hearth, and the consumption of 3% -7% reaches within 10%, thereby reaching the discharge standard.

Because the fuel powder is mixed in the gas-powder mixing cylinder after passing through the high-temperature high-pressure fan and then is sprayed into the hearth, the furnace temperature is increased by 100-200 ℃ during the tilting, and the air quantity is reduced by more than 30% by controlling the boiler blower and the induced draft fan, so that the combustion is stabilized; the fuel is sprayed after being crushed and mixed with high-temperature flue gas, and composite combustion supporting is carried out on the solid fuel burning on the circulating fluidized bed, so that the quantity of the fuel on the circulating fluidized bed can be reduced by about 30 percent, and the furnace temperature is improved and stable combustion is ensured compared with the original quantity; the flue gas with the oxygen content of 10-17% is used for replacing original air to serve as a combustion improver, and the flue gas returns to the hearth for combustion supporting, so that the defect that the excess air coefficient in the furnace is too large is greatly reduced. Meanwhile, the blast volume of the boiler is reduced, the total oxygen in the boiler is further reduced, and the generation of harmful gases such as nitrogen oxides is favorably reduced. The flue gas returns to support combustion, so that the oxygen content of the flue gas can be reduced, the rotation of a draught fan and a boiler blower can be reduced, the induced air quantity is reduced, the retention time of the flue gas in the boiler is prolonged, the full combustion is facilitated, and the energy conservation and emission reduction are realized.

The utility model aims to improve the furnace temperature, reduce the blast air and draw the amount of wind, slow down the flue gas velocity of flow, abundant burning, and detect the steam pressure in the furnace through steam pressure gauge, ensure that steam pressure is unchangeable in the furnace, if when automatic control electricity cabinet detected steam pressure decline (be the workshop with the tolerance increase promptly), then all motor parts of automatic control electricity cabinet control operate with higher speed, detect steam pressure and reach the standard of settlement until steam pressure gauge.

The utility model discloses an oxygen scale detects the oxygen content of chimney, ensures that the flue gas oxygen content is no longer than the standard of emission.

The utility model discloses can promote 100 ~ 200 degrees in the twinkling of an eye the furnace temperature, can also save fuel 10 ~ 30% simultaneously (look the thermal efficiency of reforming transform the boiler different, energy-conservation also different, in a word, the composite combustion is just like the interior stirring ware of stove, and the combustible substance and the air in the flue gas in the stove are stirred, are stirred) improve the furnace temperature after have following benefit:

1. the original heat transfer mode mainly based on convection heat conduction is changed into the heat transfer mode mainly based on radiation, and the heat transfer effect is several times faster.

2. After the temperature of the furnace is increased, under the condition of thermal diffusion, combustible gas and carbon particles which are not completely burnt out in the original furnace are quickly combusted, the heat loss of flue gas emission is reduced, and meanwhile, the flue gas emission is cleaner.

3. After the furnace temperature is increased, the flue gas in the furnace accelerates the flow by the action of high-temperature self-pulling force, reduces about 30 percent of air quantity of a draught fan and an air blower, and can directly save electric quantity.

4. The high-temperature low oxygen directly reduces the discharge of harmful substances and gases in the flue gas by more than 50 percent, and the discharge of nitrogen oxides is greatly reduced, thereby completely reaching the national discharge standard.

5. After the furnace temperature is increased, the original furnace slag is changed from black (the general heat value is about 700-1100 kilocalories) into completely white silver gray (basically completely burnt without heat value), and the heat loss of carbon contained in the original furnace slag is completely eliminated.

As shown in fig. 2, an embodiment of the gas-powder mixing structure of the present invention is: the gas-powder mixing structure 100 comprises a mixing drum 4 and a high-pressure high-temperature fan 5, wherein the upper end 4 of the mixing drum is respectively connected with a hot air pipe 200 and a powder dividing pipe 300, the high-pressure high-temperature fan 5 is installed at the bottom of the mixing drum 4, the hot air pipe 200 is connected with the high-pressure high-temperature fan 5 through an internal air duct 400 of the mixing drum 4, and an air outlet of the high-pressure high-temperature fan 5 is arranged at a powder outlet in the mixing drum 4, so that powder mixed high-temperature smoke is sprayed to the spray gun 500. Preferably, the spray gun is further provided with a sedimentation check valve 501, and the top of the mixing cylinder 4 is provided with an explosion-proof membrane 40.

As shown in fig. 3, another embodiment of the gas-powder mixing structure of the present invention is: the gas-powder mixing structure 100 comprises a mixing cylinder 4 and a high-pressure high-temperature fan 5, wherein the high-pressure high-temperature fan 5 is arranged at the bottom of the mixing cylinder 4; the upper end of the mixing cylinder 4 is connected with a powder distributing pipe 300, the hot air pipe 200 is connected with an inner flue gas pipe 201 which is arranged in the mixing cylinder 4, the inner flue gas pipe extends to the bottom from the upper end of the mixing cylinder and is then connected with a high-pressure high-temperature fan 5, and an air outlet of the high-pressure high-temperature fan 5 is butted with the spray gun 500 after being converged at a powder outlet in the mixing cylinder 4. Besides, the gas-powder mixing structure also comprises a base 101, and the mixing cylinder 4 and the high-pressure high-temperature fan 5 are fixed on the base 101. Preferably, the hot air pipe 200 and the powder dividing pipe 300 are soft pipes; the powder distributing pipe 300 is connected with the mixing cylinder 4 through a connecting flange, and the hot blast pipe 200 is connected with the inner flue gas pipe 201 through a connecting flange.

As shown in fig. 4, the rest is the same as the solution of fig. 1. The gas-powder mixing structure 100 is composed of a tail end part of a powder dividing pipe and a high-pressure high-temperature fan 5, the high-pressure high-temperature fan 5 is respectively connected with a second hot air pipe 7-1 and a second hot air pipe 7-2, then the high-temperature fan 5 accelerates high-temperature flue gas to the tail end of the powder dividing pipe through a pipeline to be mixed with powder, and finally the tail ends of the powder dividing pipes 3-1 and 3-2 are connected with injection guns 6-1 and 6-2 on two sides of a hearth 9.

The utility model discloses a high pressure high temperature fan is in the bottom of mixing drum, and it is penetrated the rifle with the rifle and is connected, through the high-pressure wind-force effect, inhales the spray gun with the powder in the mixing drum, again with high pressure fan's high-temperature wind spout together in the stir-fry acutely burn promptly.

So the workflow is: the coal is sent to a pulverizer 1 by a blanking machine, the pulverizer 1 pulverizes the coal after introducing high-temperature flue gas, then the pulverized coal is conveyed to powder dividing pipes 3-1 and 3-2 through a total powder pipe 3a, and then the pulverized coal is conveyed to a spray gun 6-1 at one side of a hearth 9 through the powder dividing pipes 3-1, the powder dividing pipes 3-2 are used as spray guns 6-2 at the other side of the hearth, one high-pressure high-temperature fan 5 is connected with a hot air pipe II 7-1, and the high-temperature flue gas is directly conveyed to the powder dividing pipes 3-1 to be mixed with powder and blown into the hearth 9; and the other high-pressure high-temperature fan 5 is connected with the hot air pipe III 7-2 and directly conveys the warm flue gas into the powder dividing pipe 3-2 to be mixed with the powder and blown into the hearth 9. Because the high-temperature fuel powder is sprayed into the hearth for combustion, the flame in the hearth is heated, and combustible gas and particles in the hearth can be burnt through in time.

The composite combustion circulating fluidized bed is characterized in that the hearth 9 is also connected with a boiler blower 15 for inducing air.

Therefore, when the oxygen content of the flue gas emission exceeds the emission standard, the boiler blower and the induced draft fan are controlled to decelerate properly, so that the induced draft quantity is reduced, and the aim of saving energy is fulfilled.

As shown in fig. 1 and 4, the combined combustion circulating fluidized bed, wherein the furnace 9 is further connected with a boiler blanking machine 9a, the boiler blanking machine 9a is controlled by a motor to perform blanking, and the motor is connected with an automatic control electric cabinet 8.

As shown in fig. 4, the complex combustion circulating fluidized bed, in which the boiler hopper 9a is installed below a coal hopper 9b, the coal hopper 9b delivers fuel particles.

The combined combustion circulating fluidized bed, wherein, the pulverizer 1 is controlled by the automatic control electric cabinet 8, so can control the fineness of the pulverized fuel of the pulverizer, and control.

As shown in fig. 1 and 4, a blanking machine 1a is connected to the crusher 1a, and the blanking machine 1a is controlled by an automatic control electric cabinet 8 to blank materials for crushing the crusher 1.

As shown in fig. 4, the blanking machine 1a is located below the small coal hopper 1 b.

Preferably, the blanking machine 1a is a screw feeder, and the boiler blanking machine 9a is a screw coal feeder.

As shown in fig. 4 and 5, the boiler blower 15 is connected to a hood 9c installed in the furnace, through which fuel particles are blown up for combustion.

As shown in fig. 5, a drum 90 for storing steam is provided at the top of the furnace 9, a water-cooling pipe 91 extending to the bottom of the furnace is provided at the bottom of the drum 90, a steam pipe 92 for sending steam to a workshop is further connected to the drum 90, and the steam pressure gauge 14 is installed on the steam pipe 92.

The working principle is as follows: the boiler blanking machine 9a conveys fuel particles falling from the coal hopper 9b into the hearth 9 for combustion, the quantity of the fed fuel is controlled by the boiler blanking machine 9a, the boiler blower 15 blows the fuel particles through the hood 9c, the flame enables water of the water cooling pipe to become water vapor, the steam rises to the boiler barrel 90 for concentration, and then the steam enters the workshop.

Preferably, the fuel pulverized by the pulverizer has a fineness of about 200 meshes, so that hot flue gas conveyed by a hot air pipe is dried and pyrolyzed in the pulverizing process, and is mixed with flue gas in a flue, then the flue gas is sprayed into a hearth by a spray gun, and a hot fireball is continuously sprayed between the inclined positions and becomes a hot fire sea when the flame contacts with the fireball, so that fuel powder and the flue gas are mixed in a powder distributing pipe and are sprayed into the hearth by the spray gun to contact with fire, so that the fuel powder and the flue gas can be rapidly combusted, and the temperature in the hearth is instantly increased.

The fuel of the utility model comprises fire coal, biomass, natural gas, heavy oil, combustible substances and the like; the whole combustion process of the fuel at present goes through 4 stages: drying/dry distillation (pyrolysis and cracking requiring some heat absorption)/combustion (release of a large amount of heat)/burnout. All the current industrial boilers directly push fuel into the boiler for combustion: i.e., the endothermic and exothermic stages Wu are performed in the furnace.

The utility model discloses be exactly carry out the external preliminary treatment of endothermal stage (dry distillation) of combustion process outside the stove, then send into the interior fast combustion of stove (simply release heat in a large number), its main function is: not only the time for burning and burnout of the fuel in the furnace is reduced, but also the loss of heat absorption and temperature reduction in the drying and dry distillation stages when the fuel enters the furnace is reduced. In addition, the temperature rises rapidly in burning, can reduce the energy consumption of fuel, in addition, the utility model discloses take the interior high temperature flue gas of stove (temperature 500 degrees, oxygen content about 15%) to handle fuel and mix the fuel powder and spout and burn rapidly in burning to can improve the furnace temperature about 100 + heat 200 degrees, the fume emission harmful gas/dust reduces more than 60%. The innovative technical equipment of 'high-temperature low-oxygen' energy-saving emission-reducing clean combustion, which is vigorously recommended by relevant government departments in the world and China at present, is really realized.

Case (2): a4-ton biomass fuel circulating fluidized bed is modified, high-temperature flue gas in a hearth is adopted to crush fuel, meanwhile, high-temperature flue gas in the furnace is used for jetting powder at a high speed (flue gas/fuel powder mixing is carried out) to enter the hearth for combustion, and the furnace temperature is increased by more than 100 ℃ between inclinations. Meanwhile, the air quantity of a boiler blower and an induced draft fan is reduced by more than 30%, and combustion is stabilized. Firstly, energy-saving sources: after being crushed by 5 percent of the total amount of fuel, the pulverized fuel is mixed with high-temperature flue gas for injection, and the solid fuel burning on the circulating fluidized bed is subjected to composite combustion supporting, so that the quantity of the fuel on the circulating fluidized bed can be reduced by about 30 percent, and the furnace temperature is improved and stable combustion is ensured compared with the original furnace temperature. Secondly, smoke with the oxygen content of 10-17% is adopted to replace original air to serve as a combustion improver, so that the defect of overlarge excess air coefficient in the furnace is greatly reduced; meanwhile, the blast volume of the boiler is reduced, the total oxygen in the boiler is further reduced, and the generation of harmful gases such as nitrogen oxides is favorably reduced. In addition, the induced air quantity is reduced, so that the retention time of the flue gas in the furnace is prolonged, the full combustion is facilitated, the energy is saved, and the emission is reduced.

The above is a preferred embodiment of the present invention, and certainly not to limit the scope of the present invention, it should be noted that, for those skilled in the art, modifications or equivalent substitutions of the technical solutions of the present invention without creative efforts may not depart from the protection scope of the technical solutions of the present invention.

Claims

1. A composite combustion circulating fluidized bed is characterized by comprising an automatic control electric cabinet, a pulverizer, a hearth of the fluidized bed, a chimney, a flue for connecting the chimney and the hearth, a hot air pipe, a powder pipe and a gas-powder mixed structure; the powder pipe comprises a main powder pipe and a powder dividing pipe, and the main powder pipe is connected with the pulverizer and the powder dividing pipe; one hot air pipe is communicated with the pulverizer and the flue, and the other two hot air pipes are used for connecting the flue and the gas-powder mixing structure together; the gas-powder mixing structure mixes the powder conveyed by the powder dividing pipe and the high-temperature flue gas conveyed by the hot air pipe and then sprays the mixture to two sides of the hearth; the flue is communicated with the chimney through an induced draft fan, the chimney is provided with an oxygen meter for detecting the oxygen content in the discharged waste gas, and the hearth is also provided with a steam pressure gauge for detecting the steam pressure in the hearth; the automatic control electric cabinet is respectively connected with the pulverizer, the gas-powder mixing structure, the draught fan, the steam pressure meter and the oxygen meter.

2. The composite combustion circulating fluidized bed of claim 1, wherein the gas-powder mixing structure sprays the mixed gas-powder to both sides of the furnace through the spray gun, the gas-powder mixing structure comprises a high-pressure high-temperature blower and a mixing barrel, the upper end of the mixing barrel is respectively connected with a hot air pipe and a powder dividing pipe, the high-pressure high-temperature blower is installed at the bottom of the mixing barrel, the hot air pipe is connected with the high-pressure high-temperature blower through an internal air duct of the mixing barrel, and an air outlet of the high-pressure high-temperature blower is arranged at a powder outlet in the mixing barrel, so that the powder mixed high-temperature flue gas is sprayed into the spray gun.

3. The combined combustion circulating fluidized bed of claim 2, wherein the high-pressure high-temperature fan is connected with a control electric cabinet.

4. The combined combustion circulating fluidized bed according to claim 1, wherein the furnace is further connected with a boiler blower for increasing the air volume in the furnace.

5. The combined combustion circulating fluidized bed according to claim 2, wherein the mixing cylinder injects the mixed gas powder from one side of the furnace to the center of the flame in the furnace through the injection gun, and the mixing cylinder injects the mixed gas powder from the other side of the furnace to the center of the flame in the furnace through the injection gun.

6. The combined combustion circulating fluidized bed of claim 1, wherein a boiler blanking machine is connected to the furnace, the boiler blanking machine is controlled by a motor to perform blanking, and the motor is connected to an automatic control electric cabinet.

7. The complex combustion circulating fluidized bed of claim 6, wherein the boiler blanking machine is installed below a coal hopper.

8. The complex combustion circulating fluidized bed of claim 1, wherein the pulverizer is controlled by an automatically controlled electric cabinet.

9. The combined combustion circulating fluidized bed of claim 1, wherein a blanking machine is connected to the pulverizer, the blanking machine is controlled by an automatic control electric cabinet to blank materials for the pulverizer to pulverize, and the blanking machine is located below the coal hopper.

10. The complex combustion circulating fluidized bed of claim 9, wherein the blanking machine is a screw feeder.