CN207632751U - A kind of Biomass Gasification in Circulating Fluidized Bed device - Google Patents

Abstract

The utility model relates to a biomass circulating fluidized bed gasification device, which comprises a fluidized bed gasification furnace body, an air supply mechanism connected with the bottom end of the fluidized bed gasification furnace body, and an air supply mechanism arranged on the fluidized bed gasification furnace body. The feeding mechanism on the side, and the first-stage cyclone separator and the return device that form a circulating fluidized structure with the fluidized bed gasifier body, the fluidized bed gasifier body, the first-stage cyclone separator and the return The feeders are connected to each other in turn, and the feeders are respectively connected to the feeder blower and the steam supply mechanism. The device provided by the utility model adopts steam return material to avoid slagging of return material.

Description

A kind of biomass circulating fluidized bed gasification device

technical field

The utility model relates to the technical field of biomass thermochemical equipment, in particular to a biomass circulating fluidized bed gasification device.

Background technique

Gasification is an important means of clean utilization of coal, biomass, garbage, sludge and other organic wastes, and has been widely used in chemical industry, metallurgy, civil and industrial gas and other fields. The performance of gasification technology directly affects the healthy development of these industries, plays a pivotal role in the control of energy conservation and emission reduction, and is an important guarantee for the realization of relevant national control goals. Coal gasification technology has been developed for hundreds of years, and the gasification technology of biomass and other organic wastes has also developed rapidly since the 1980s.

In recent years, with the country's emphasis on biomass utilization technology, biomass gasification coupled power generation technology has been vigorously developed due to its flexible scale and high power generation efficiency. Biomass gasification technology can be divided into fixed bed technology (updraft, downdraft, horizontal suction) and fluidized bed technology (bubbling bed, circulating bed, double fluidized bed) according to the gasifier. Among them, the fixed bed gasifier has a simple structure but small scale, poor fuel adaptability, uneven temperature, poor heat transfer, and it is difficult to control the temperature during biomass gasification, while the fluidized bed gasifier has a large processing scale and high temperature Uniform, easy to enlarge, suitable for areas with concentrated biomass resources.

However, there are still many defects in the fluidized bed gasifier in the prior art. For example, the Chinese invention patent (CN106675660 A) discloses a high-efficiency circulating fluidized bed gasification device, including a riser and a separator, and the lower part of the separator is connected to There is a feeder, and one side of the feeder is connected with the riser. When the feeder returns the semi-coke coarse powder to the riser, the return air is blown by air, which is likely to cause combustion of solid carbon particles and cause slagging of the returned material.

Another example is the Chinese invention patent (CN 103216843 A) which discloses a biomass gasification combustion boiler, which includes a primary separator, a secondary separator, a gas boiler and a rear heating surface connected in sequence. Biomass gas enters the gas-fired boiler for combustion after being dedusted by the primary and secondary separators. The lack of adsorption of fly ash may easily cause alkali metal slagging and tar corrosion and blockage on the heating surface of the boiler and tail.

Therefore, it is necessary to provide a new type of biomass circulating fluidized bed, which can avoid the occurrence of slagging and reduce the harm caused by alkali metal and tar.

Utility model content

The purpose of the utility model is to provide a biomass circulating fluidized bed gasification device for the deficiencies of the prior art, which uses steam to return material to avoid slagging of the returned material.

The technical scheme provided by the utility model is:

A biomass circulating fluidized bed gasification device, comprising a fluidized bed gasifier body, an air supply mechanism connected to the bottom end of the fluidized bed gasifier body, and an air supply mechanism arranged on the side of the fluidized bed gasifier body The feeding mechanism, and the first-stage cyclone separator and the feeder that form a circulating fluidized structure with the fluidized bed gasifier body, the fluidized bed gasifier body, the first-stage cyclone separator and the feeder are mutually mutually connected, the feeder is respectively connected to the feeder blower and the steam supply mechanism.

In the above technical scheme, when the device is started in a cold state, the feeder adopts the air blast of the feeder fan, and the feeder fan is connected to the feeder through the air supply pipe; after entering the working state, the steam supply mechanism is used to switch to the steam blower. The air return material eliminates the possibility that the air blast will burn the gas, ensuring the reliability of the return material, and at the same time, the steam has the function of temperature control, making the gasification operation more stable.

Preferably, the body of the fluidized bed gasifier is gasified with air and steam, the operating temperature is 700-900° C., and the operating wind speed in the body of the fluidized bed gasifier is 3-5 m/s.

Preferably, the feeder includes a feed back chamber and a feed chamber, the feed chamber is connected to the body of the fluidized bed gasifier, the feed chamber is connected to the first-stage cyclone separator, and is separated by a partition with communication holes in the middle, There are also slag discharge pipes, inspection ports, pressure measuring tubes and temperature measuring points on the feeder. The feeder realizes the return of materials to the body of the fluidized bed gasifier. The bottom of the feeder is an air chamber, which is connected to the feeder fan and the steam supply mechanism respectively, and can be blasted or steamed to feed back. Further preferably, the return blower is a Roots blower.

The steam blowing at the bottom of the feeder prevents gas backflow and material return. The unreacted material particles enter the feeder from the first-stage cyclone separator through the sealing leg, and go through a U-shaped route in the feeder. The legs are re-conveyed to the body of the fluidized bed gasifier to complete the material circulation.

Preferably, a steam superheater, a steam generator, a secondary cyclone separator and an ash cooler are sequentially arranged on the gas pipeline at the outlet of the primary cyclone separator. The gas is separated by the first-stage cyclone separator and discharged from the gas pipeline at the top to realize the separation of solids (coke, ash, bed material) and gas, and the heat is exchanged through the steam superheater and steam generator in turn, and the gas is cooled to below 500 °C , the ash in the gas will adsorb alkali metals and tar during the whole process. The gas at the outlet of the steam generator passes through the secondary cyclone separator, and the gas at the outlet of the secondary cyclone separator can be sent to the power plant boiler for combustion and power generation. After being cooled by the ash cooler, the separated semi-coke is sealed with circulating nitrogen and sent to the molding machine for molding. Since the secondary cyclone separator is arranged after the tail heating surface, the fly ash can absorb more tar and alkali metals before being separated, which reduces the slagging of the heat exchange surface, ensures the utilization of heat, and improves the overall thermal efficiency; secondly, The risk of tar blockage in subsequent gas utilization devices and pipelines is reduced.

Preferably, the steam supply mechanism includes a cold water source, a feed water line provided with a feed water pump, and a steam line provided with the steam superheater and the steam generator; the cold water source, the feed water line, the steam line and the return material connected in sequence. The cold water is sent to the steam generator and the steam superheater through the water supply pipeline, and through the heat exchange with the gas, superheated steam can be obtained, the temperature reaches 450°C, and the superheated steam is sent into the feeder for steam return. Further preferably, an external discharge pipe can be set on the steam pipeline passing through the steam superheater, and the excess superheated steam can be used for delivery and sale.

Preferably, a feed water pump, an ash cooler, a deaerator, a primary economizer, and a secondary economizer are sequentially provided on the water supply pipeline, and the end of the water supply pipeline is connected to a steam generator. Further preferably, a pressurized water pump is also provided on the water supply pipeline, and the pressurized water pump is arranged between the deaerator and the primary economizer.

Preferably, the steam pipeline passing through the steam superheater is provided with a first circulation pipeline, and the first circulation pipeline is connected to a secondary economizer, a primary economizer and a deaerator in sequence. This setting recycles excess superheated steam, and utilizes the primary economizer and secondary economizer to preheat the water so that the saturated water temperature reaches 300°C when it enters the steam generator. The cooled circulating water is combined by the deaerator, which can not only remove the oxygen in the water, but also be used for the merging of the circulating water.

Preferably, the air supply mechanism includes a blower and an air pipeline; the air pipeline is connected to the bottom of the fluidized bed gasifier body, and the air pipeline is provided with a primary air preheater, a secondary air preheater and a third air preheater in sequence. stage air preheater.

Preferably, the steam line passing through the steam superheater is provided with a second circulation line, and the second circulation line is connected to the pressure reducer, the third-stage air preheater, the second-stage air pre-heater, the first-stage air pre-heater and the deaerator. This setting recycles excess superheated steam, and uses three-stage air preheater, two-stage air preheater and one-stage air preheater to heat the air to 260°C and send it into the air chamber at the bottom of the fluidized bed gasifier body. The bed material is fluidized through the wind cap on the air distribution plate, and the bed material is used as a gasification agent to undergo a gasification reaction with the biomass raw material.

Preferably, a third circulation pipeline is provided on the water supply pipeline passing through the ash cooler; a cooling tower is provided on the third circulation pipeline, and both ends of the third circulation pipeline are respectively connected to the inlet end of the feed water pump and the cooling tower. The outlet port of the ashes. This setting recycles the water heated by the ash cooler to reduce the waste of water resources.

Preferably, the feeding mechanism includes a floor material bin, a hoist, a hopper, and an auger feeder; the body of the fluidized bed gasifier is connected to the hopper through the auger feeder. The feeding mechanism makes it possible to use solid shaped biomass as a gasification raw material, and the solid shaped raw material has good adaptability and is convenient for transportation.

Preferably, the auger feeder includes a primary auger feeder and a secondary auger feeder connected in sequence.

When the feeding system is running, the elevator transports the biomass raw material from the ground material bin to the hopper in the air. The two feeders at the bottom of the hopper evenly feed the material to the first-stage auger feeder to avoid pressure on the first-stage auger feeder. The first-stage auger feeder is a variable-pitch dragon to ensure that the discharge at the outlet is unobstructed and not blocked, and then the raw materials are fed into the body of the fluidized bed gasifier through the second-stage auger feeder. The feeder is used to avoid the bridging of biomass particles, the variable pitch auger is used to ensure continuous and uniform feeding, and the secondary auger feeder is fast feeding, which can ensure that the material is quickly fed into the body of the fluidized bed gasifier for reaction.

Compared with the prior art, the beneficial effects of the utility model are reflected in:

(1) The biomass circulating fluidized bed gasification device provided by the utility model adopts circulating steam to return material to avoid burning of carbon particles and slagging of returned material.

(2) In the biomass circulating fluidized bed gasification device provided by the utility model, the secondary cyclone separator is arranged behind the tail heating surface, so that the fly ash can absorb more tar and alkali metal before being separated, reducing It prevents slagging on the heat exchange surface, ensures the utilization of heat, improves the overall thermal efficiency, and reduces the risk of tar clogging.

(3) The biomass circulating fluidized bed gasification device provided by the utility model uses the first circulation pipeline to cooperate with the first-level economizer and the second-level economizer to preheat the water, so that when entering the steam generator The saturated water temperature reaches 300°C, which reduces the condensation corrosion of the steam generator.

(4) The biomass circulating fluidized bed gasification device provided by the utility model uses the second circulation pipeline to cooperate with the third-stage air preheater, the second-stage air preheater and the first-stage air preheater to heat the air to 260 ° C, so that It is used as a gasification agent to realize the gasification reaction.

Description of drawings

Fig. 1 is the structural representation of biomass circulating fluidized bed gasification device in the embodiment;

Fig. 2 is a diagram of the operating state of the biomass circulating fluidized bed gasification device in the embodiment under specific working conditions.

Among them, 1 is the body of the fluidized bed gasifier; 2 is the floor material bin; 3 is the hoist; 4 is the hopper; 5 is the primary auger feeder; 6 is the secondary auger feeder; 7 is the primary cyclone Separator; 8 is a feeder; 9 is a Roots blower; 10 is a steam superheater; 11 is a steam generator; 12 is a secondary cyclone separator; 13 is a steam drum; 14 is a cooling tower; 15 is a pressure reducer ; 16 is blower; 17 is primary air preheater; 18 is secondary air preheater; 19 is tertiary air preheater; 20 is feed pump; 21 is ash cooler; 22 is deaerator; 23 is pressurization water pump; 24 is a primary economizer; 25 is a secondary economizer.

Detailed ways

Below in conjunction with specific embodiment the utility model is further described.

Example:

The biomass circulating fluidized bed gasification device shown in Figure 1 includes a fluidized bed gasification furnace body 1, an air supply mechanism connected to the bottom end of the fluidized bed gasification furnace body 1, and a fluidized bed gasification device. The feeding mechanism on the side of the furnace body 1, and the first-stage cyclone separator 7 and the feeder 8 forming a circulating fluidized structure with the fluidized bed gasifier body 1 .

The body 1 of the fluidized bed gasifier includes an upper dilute phase area, a lower dense phase area and a bottom air chamber. The side of the bottom air chamber of the fluidized bed gasifier body 1 is provided with a light oil burner and a fluidized bed gasifier body The 1 air chamber is connected, and the upper part of the fluidized bed gasifier body 1 air chamber is equipped with an air distribution plate and a wind cap.

The feeding mechanism includes a ground fabric bin 2, a hoist 3, a hopper 4, a primary auger feeder 5 and a secondary auger feeder 6. When the feeding system is in operation, the hoist 3 transports the biomass raw material from the ground material bin 2 to the hopper 4 in the air. The two feeders at the bottom of the hopper 4 evenly feed the material to the first-stage auger feeder 5 to prevent the first-stage auger feeder 5 from being under pressure. The first-stage auger feeder 5 is a variable-pitch dragon to ensure that the discharge at the outlet is smooth and not blocked, and then the raw materials are fed into the fluidized bed gasifier body 1 through the second-stage auger feeder 6, and the fluidized bed gasifier body The biomass raw material inlet of 1 is set in the upper dilute phase area of the body 1 of the fluidized bed gasifier.

The air supply mechanism connected to the bottom air chamber of the fluidized bed gasifier body 1 includes a blower 16 and an air pipeline, the air pipeline is connected to the bottom air chamber of the fluidized bed gasifier body 1, and the air pipeline is also provided with a first-stage air preheater in turn. 17, secondary air preheater 18 and tertiary air preheater 19.

The body 1 of the fluidized bed gasifier, the first-stage cyclone separator 7 and the feeder 8 are sequentially connected to each other to form a circulating fluidized structure. The feeding device 8 includes a feeding chamber and a feeding chamber, the feeding chamber is connected to the body 1 of the fluidized bed gasifier, the feeding chamber is connected to the first-stage cyclone separator 7, and the middle is separated by a partition with a communication hole, and the feeding chamber A slag discharge pipe, an inspection port, a pressure measuring tube and a temperature measuring point are also arranged on the device 8. The feeder 8 realizes the return of materials to the body 1 of the fluidized bed gasifier. The bottom of the feeder 8 is an air chamber, which is respectively connected to the Roots blower 9 and the steam supply mechanism, and can be blown by air or steam to return the material.

A steam superheater 10 , a steam generator 11 , a secondary cyclone separator 12 and an ash cooler 21 are arranged in sequence on the gas pipeline at the outlet of the primary cyclone separator 7 . The gas is separated by the first-stage cyclone separator 7 and discharged from the gas pipeline at the top to realize the separation of solids (coke, ash, bed material) and gas, and the heat is exchanged through the steam superheater 10 and the steam generator 11 in turn, and the gas is cooled. The ash in the gas will adsorb alkali metals and tars throughout the process. The gas at the outlet of the steam generator 11 passes through the secondary cyclone separator 12, and the gas at the outlet of the secondary cyclone separator 12 can be sent to the power plant boiler for combustion and power generation. After the separated semi-coke is cooled by the ash cooler 21, it is sealed with circulating nitrogen and sent to molding machine forming.

The steam supply mechanism includes a cold water source, a feed water line provided with a feed water pump 20, and a steam line provided with a steam superheater 10 and a steam generator 11, wherein the cold water source, the feed water line, and the steam line are connected to the feeder 8 in sequence. The water supply pipeline is successively provided with a water supply pump 20, an ash cooler 21, a deaerator 22, a pressurized water pump 23, a primary economizer 24 and a secondary economizer 25, and the end of the water supply pipeline is connected to the steam generator 11, and the steam The pipeline is provided with a steam generator 11, a steam drum 13 and a steam superheater 10 in sequence. Wherein, the steam superheater 10 and the steam generator 11 adopt serpentine tube structure.

Among them, the steam pipeline passing through the steam superheater 10 is divided into four pipelines, the first pipeline is the first circulation pipeline, and the first circulation pipeline is connected to the secondary economizer 25 , the primary economizer 24 and the deaerator 22 in sequence. The second pipeline is the second circulation pipeline, and the second circulation pipeline is connected to the pressure reducer 15 , the third-stage air preheater 19 , the second-stage air preheater 18 , the first-stage air preheater 17 and the deaerator 21 in sequence. The third pipeline sends excess superheated steam directly. And the fourth pipeline is communicated with the feeder 8 for realizing the steam feed back.

In addition, a third circulation pipeline is provided on the water supply pipeline passing through the ash cooler 21, and a cooling tower 14 is arranged on the third circulation pipeline, and the two ends are respectively connected to the inlet end of the feed water pump 20 and the outlet end of the ash cooler 21, This setting recycles the water heated by the ash cooler 21 to reduce the waste of water resources.

work process:

When the device is started, the air blower 16 is first turned on, and the light oil burner under the body 1 of the fluidized bed gasifier is used to ignite and heat the air chamber and the furnace. At this time, the feeder 8 adopts the Roots blower 9 air blast.

After the system is stabilized, the feeder 8 switches the steam blowing, and then increases the amount of biomass feed, and enters the gasification state when there is no excess oxygen at the outlet, adjusts the air volume, and the temperature of the fluidized bed gasifier body 1 drops to 700 At -900°C, the system runs stably.

When the system is running stably, the pulverized biomass raw material enters the body 1 of the fluidized bed gasification furnace from the hopper 4 through the auger feeder, and is pyrolyzed and gasified under the heating of the high-temperature bed material and the combustion aided by air and steam. The air blasts. The produced gas and solid particles enter the first-stage cyclone separator 7 through the outlet 1 of the fluidized bed gasifier body. Return to the fluidized bed gasifier body 1 for the next round of gasification.

After the high-temperature gas at the outlet 1 of the fluidized bed gasifier body is dedusted by the first-stage cyclone separator 7, it passes through the steam superheater 10 and the steam generator 11 in turn for heat exchange, and the gas itself is cooled to about 475°C. The gas at the outlet of the steam generator 11 enters the secondary cyclone separator 12, and the separated semi-coke is cooled by the ash cooler 21 and sent to a molding machine for take-out. The gas at the outlet of the secondary cyclone separator 12 is sent to the boiler of the power plant for combustion and power generation.

The following is the changing state of air, gas and water vapor under specific working conditions, as shown in Figure 2, which is only to illustrate the technical effect of the device, and does not limit the scope of protection.

Among them, the air flow is as follows: when the cold air enters, the temperature is 20°C, and the blower 16 is used to pressurize the air, and the air volume is 20366Nm ³ /h. 18 is preheated to 222°C, preheated to 260°C by the three-stage air preheater 19, and sent to the air chamber at the bottom of the body 1 of the fluidized bed gasifier, and the bed material is fluidized through the air distribution cap on the air distribution plate , and as gasification agent and biomass raw material for gasification reaction.

The gas flow is as follows: gas is generated in the fluidized bed gasifier body 1 at a temperature of 750°C and the gas volume is 41244.7Nm ³ /h, and enters the first stage at the outlet of the fluidized bed gasifier body 1 at a speed of 25m/s The cyclone separator 7 performs gas-solid separation, and it is discharged from the exhaust pipe at the top of the separator and then enters the heating surface at the tail, where it passes through the steam superheater 10 and the steam generator 11 in turn for heat exchange, and the temperature of the gas is cooled to 475°C. The velocity enters the secondary cyclone separator 12 for separation.

The flow of water vapor is as follows: the flow rate of cold water at 30°C is 5163kg/h, the pressurized flow rate through the feed water pump 20 is 8163kg/h, 1MPa, and the temperature of the semi-coke separated by cooling through the ash cooler 21 reaches 80°C, and the total flow rate is 8165kg/h h. Among them, 3002kg/h is returned to the inlet of the ash cooler 21 for circulation after being cooled by the cooling tower 14, and the remaining 5163kg/h enters the deaerator 22 for collection. The water temperature at the outlet of the deaerator 22 is 175°C, and the outlet flow rate is 10889kg/h. It is heated to 277°C by the first-stage economizer 24, and the saturated water is 311°C by the second-stage economizer 25. Then it enters the steam generator 11 and is superheated by steam. The device 10 is heated to 450°C with 10MPa superheated steam.

Extract 3965kg/h from the superheated steam and send it to the primary and secondary economizers to heat the feed water. After passing through the secondary economizer 25, it becomes 311℃ saturated steam, and after passing through the primary economizer 24, it becomes 311℃ saturated water, and finally Then enter the deaerator 22 for collection; extract 1762kg/h and depressurize to 4MPa, then enter the steam air preheater to heat the air, pass through the third-stage air preheater 19, and then become 250°C saturated steam, and after passing through the second-stage air preheater 18, become saturated steam It becomes saturated water at 250°C, which becomes condensed water at 100°C after passing through the three-stage air preheater 17, and then enters the deaerator 22 for collection; 1510kg/h steam is extracted for use as return steam; the remaining 3653kg/h steam is sent out.

Claims (10)

1. A biomass circulating fluidized bed gasification device, comprising a fluidized bed gasifier body, an air supply mechanism connected to the bottom end of the fluidized bed gasifier body, and arranged on the side of the fluidized bed gasifier body The feeding mechanism above, and the first-stage cyclone separator and the return device that form a circulating fluidized structure with the fluidized bed gasifier body, are characterized in that the fluidized bed gasifier body, the first-stage cyclone separator The feeder is connected with each other in turn, and the feeder is respectively connected with a feeder blower and a steam supply mechanism. 2. The biomass circulating fluidized bed gasification device according to claim 1, wherein a steam superheater, a steam generator, and a secondary cyclone are arranged successively on the gas pipeline at the outlet of the primary cyclone separator. Separators and coolers. 3. The biomass circulating fluidized bed gasification device according to claim 2, characterized in that, the steam supply mechanism includes a cold water source, a feed water pipeline provided with a feed water pump, and the steam superheater and the steam superheater are provided. The steam pipeline of the steam generator; the cold water source, the water supply pipeline, the steam pipeline and the feeder are sequentially connected. 4. The biomass circulating fluidized bed gasification device according to claim 3, wherein a feed water pump, an ash cooler, a deaerator, a primary economizer, and a secondary Economizer, the end of the water supply pipeline is connected to the steam generator. 5. The biomass circulating fluidized bed gasification device according to claim 4, characterized in that, the steam pipeline passing through the steam superheater is provided with a first circulation pipeline, and the first circulation pipeline is connected to two stages in sequence. Economizers, primary economizers and deaerators. 6. The biomass circulating fluidized bed gasification device according to claim 4, wherein the air supply mechanism includes a blower and an air pipeline; the air pipeline is connected to the bottom end of the fluidized bed gasifier body, The air pipeline is provided with a primary air preheater, a secondary air preheater and a tertiary air preheater in sequence. 7. The biomass circulating fluidized bed gasification device according to claim 6, characterized in that, the steam pipeline passing through the steam superheater is provided with a second circulation pipeline, and the second circulation pipeline is sequentially connected to decompression Air preheater, tertiary air preheater, secondary air preheater, primary air preheater and deaerator. 8. The biomass circulating fluidized bed gasification device according to claim 4, characterized in that, a third circulation pipeline is provided on the water supply pipeline passing through the ash cooler; tower, and the two ends of the third circulation pipeline are respectively connected to the inlet end of the feed water pump and the outlet end of the ash cooler. 9. The biomass circulating fluidized bed gasification device according to claim 1, characterized in that, the feeding mechanism comprises a floor material bin, a hoist, a hopper and an auger feeder; the fluidized bed gasification The furnace body is connected with the hopper through the auger feeder. 10 . The biomass circulating fluidized bed gasification device according to claim 9 , wherein the auger feeder comprises a primary auger feeder and a secondary auger feeder connected in sequence. 11 .