CN203238227U - System for pressurized fluidized bed - Google Patents

Abstract

The utility model relates to a pressurized fluidized bed system for coal gasification, which solves the problems of unstable system and poor removal of impurities, dust and slag in the existing system. The technical solution includes a pressurized fluidized bed, and the reaction gas outlet of the pressurized fluidized bed gasifier is sequentially connected to an organic matter decomposition device, a cyclone dust collector, a waste heat boiler, a high temperature filter and a washing tower. The utility model has the advantages of simple system, convenient operation, high reliability, low operation cost, excellent product gas quality and stable system operation.

Description

Pressurized fluidized bed system

technical field

The utility model relates to a coal gasification system, in particular to a pressurized fluidized bed system for coal gasification.

Background technique

my country is a country with little oil, gas shortage and relatively rich coal. High-moisture, high-ash low-quality coal accounts for a large proportion. In the past ten years, my country's coal gasification production technology has made great progress, and various coal technology has been continuously improved and improved. With the country's increasing efforts in energy conservation and emission reduction, coal gasification technology has become more and more popular in all aspects. Pay attention to.

Coal gasification is simply divided into three categories, including: fixed bed gasification, fluidized bed gasification and entrained bed gasification. Atmospheric pressure intermittent gasification in fixed bed gasification has been stopped by the state due to pollution and other problems. Pressurized fixed bed gasification, represented by Lurgi furnace, also has problems such as wastewater treatment difficulties; entrained bed gasification has wet GE- Texaco gasifier is represented by the four-nozzle gasifier of East China University of Science and Technology, and the dry process is represented by Shell, GSP, aerospace furnace, two-stage furnace, etc. The former has higher requirements on coal quality, while the latter has relatively low investment High, taking Shell gasification as an example, the investment of a single gasifier with a coal input of 2,000 tons/day is about 800 million, and the construction period is long; the current representative fluidized bed gasification is: Ende furnace , U-GAS, KBR, ash fusion, etc., except for the Ende furnace for atmospheric pressure gasification, other pressurized fluidized beds have not yet had large-scale industrial demonstration operation devices, and they are all in the construction stage and have not been successfully demonstrated. At present, the large amount of low-quality coal in Xinjiang, Inner Mongolia, etc., which are the main producing areas of coal in my country, needs to be gasified by pressurized fluidized bed gasifiers with less investment and larger processing capacity in terms of coal type adaptability to produce Chemical Products.

At present, the fluidized bed device is basically mature in atmospheric gasification, but it has not been successful in pressurization, mainly in the following aspects: 1. The feed system is unstable and unsafe. The traditional fluidized bed adopts spiral coal feeding The machine feeds the gasifier. This feeding method has the risk of uneven feeding, easy blockage and leakage during pressurized gasification. For example, once the pulverized coal leaks, the combustion of pulverized coal will be extremely unsafe; 2 is Since the operating temperature of the fluidized bed is 900-1000°C, the raw gas produced contains more tar, phenol, naphthalene, benzene and other organic substances, which will make it difficult to deal with the subsequent purification equipment, especially after washing with water. Wastewater containing tar and phenol is extremely difficult to treat, and the investment and consumption are high; 3. In terms of gasification and slag removal, the current traditional atmospheric fluidized bed uses a slag cooler to remove slag. If pressurized gasification is used, it will make The seal of the slag cooler is leaked and stuck, and the slag discharge temperature cannot be lowered, resulting in shutdown; 4. In terms of coarse coal gasification and dedusting, the current traditional fluidized bed is dedusted by a cyclone separator, and the waste heat is recovered and directly enters the washing tower for washing, and then Water film dedusting with Venturi is used to achieve a dust content of ≤35mg/Nm ³ in the crude gas. This type of process has a poor dedusting effect and produces a lot of dusty wastewater with high treatment costs.

Contents of the invention

The purpose of this utility model is to solve the above technical problems and provide a pressure fluidized coal gasification system with simple structure, easy operation, high reliability, low operating cost, excellent product gas quality, low equipment investment and stable system operation. bed system.

The pressurized fluidized bed system of the utility model includes a pressurized fluidized bed, and the reaction gas outlet of the pressurized fluidized bed gasification furnace is sequentially connected with an organic matter decomposition device, a cyclone dust collector, a waste heat boiler, a high temperature filter and a washing tower .

The organic matter decomposition device includes a cylinder coated with a refractory paint layer, an inlet and an outlet are arranged at both ends of the cylinder, and at least one packing area is arranged at intervals in the cylinder.

The diameter of the cylinder body is 6-10 times that of the gas delivery pipeline.

The packing area includes a multi-layer structured packing layer installed in a fixed plate net, and through holes are staggered on the multi-layer structured packing layer, and the diameter of the through hole is 50-100mm. The spacing is 600-1000mm.

The fixed plate net is a water-cooled jacket fixed plate net that can be fed with cooling water.

The ash and slag outlet of the pressurized fluidized bed gasifier is sequentially connected with a chilling chamber, a material sealing bin, a slag discharge decompression device, a decompression tank and a slag cooler.

The slag discharge decompression device includes a decompression pipe and a vent pipe located below the decompression pipe. The decompression pipe has a diameter-reducing section, and the pipe wall of the vent pipe includes a filter layer, an annular space from the inside to the outside. cavity and an outer tube, and the annular cavity communicates with the vent valve.

The annular cavity is also communicated with the blowback pipe.

There are at least two slag discharge decompression devices connected in series.

The ash outlet of the cyclone dust collector is connected with the lower section of the pressurized fluidized bed gasifier through a non-mechanical valve.

The process of using the above system includes the following steps: the pulverized coal is transported into the pressurized fluidized bed gasification furnace under pressure, and directly contacts and reacts with the gasification agent to form a dense phase section in the upper part of the furnace, and a dilute phase section in the lower part. After the reaction The crude gas is firstly decomposed by the organic matter decomposition device to decompose the organic matter contained in the gas, and then sent to the waste heat boiler to cool down to 300-350°C after being dedusted by the cyclone, and then further dedusted by the high-temperature filter, and the dedusted crude gas enters the washing tower for washing The crude gas with dust content ≤ 1mg/ ^Nm3 is sent to the downstream device. Preferably, the reaction temperature of the dense phase section is 950-1000° C., and the gasification pressure is 3.0-4.0 MpaG.

The residence time of the reacted crude gas in the organic matter decomposition device is 3-15s to fully decompose the organic matter contained in the gas, and then sent to the waste heat boiler after cyclone dust removal.

After the pulverized coal is pressurized by the coal lock hopper, the pulverized coal is sent into the pressurized fluidized bed gasifier by means of pneumatic conveying under the delivery of the pulverized coal sending tank.

The reacted slag in the pressurized fluidized bed gasification furnace is lowered to the bottom of the furnace, chilled to 300-450°C in the quenching chamber, and then sent to the decompression tank for decompression through the material sealing bin and slag discharge decompression device To below 0.2MPa (G), finally through the slag cooler to cool again and then discharged from the system.

The dust collected after the cyclone dust removal is returned to the lower section of the pressurized fluidized bed gasifier through the non-mechanical valve under the action of loose gas, and participates in the gasification reaction again.

When there is too much tar attached in the organic matter decomposing device, the outlet gas temperature of the pressurized fluidized bed gasifier is increased in a short period of time, so that the tar in the organic matter decomposing device is quickly decomposed and then returned to the normal operating temperature. The range of increasing the temperature of the furnace gas is 50-100°C.

The inventor analyzed the crude gas from the reaction furnace in the existing pressurized fluidized bed process and found that in order to obtain high-quality gas and facilitate the normal operation of subsequent devices, the tar, phenol, naphthalene, and benzene contained in the crude gas It is very necessary to wait for the effective removal of organic matter, and this type of organic matter can be rapidly decomposed under high temperature and within a certain period of time. However, since the pressurized fluidized bed process is a high-temperature and high-pressure working condition, the flow rate of crude gas in the pipeline is fast and the pressure is high, so it is difficult to meet the conditions for pyrolysis of organic matter before cooling down. It is difficult to achieve 80m or even longer in industry. Therefore, it is considered to add an organic matter decomposition device to meet the residence time of the crude gas at high temperature. The crude gas after the gasification reaction first stays in the organic matter decomposition device for a period of time. Tar, phenol, naphthalene, benzene and other organic matter are decomposed at high temperature, and then the cyclone dust removal is carried out to remove large particles of dust. Since the organic matter in the crude gas has basically been removed, there is no problem of tar and other organic matter blocking the pipeline after cooling down, so it can be After the heat exchange and cooling of the waste heat boiler, the high temperature filter is used to filter out the fine dust, thereby reducing the investment cost of the equipment (the performance requirements of the high temperature resistant material are low), improving the reliability and safety performance of the system, and also improving the fineness of by-products. gray quality.

The organic matter decomposition device can be an empty cylinder with a relatively large diameter, and a packing area is set in the empty cylinder to ensure the residence time of the crude gas in the device, but considering the high gas flow rate, high temperature and high pressure of the crude gas In order to ensure that the organic matter in the crude gas is fully decomposed, the packing area is preferably made of multi-layer structured packing installed in a fixed plate net. The multi-layer structured packing is staggered with through holes, and the diameter of the through holes is 50-100mm, if the hole diameter is too large, the stop effect will not be achieved, if it is too small, the fly ash in the gas will be blocked here; the distance between each layer of structured packing is 600-1000mm, if the distance is too large, the length of the equipment will be lengthened, and the distance between If it is too small, the gas will not be evenly distributed. The staggered arrangement of the through holes can further reduce the flow rate of the crude gas and improve the decomposition efficiency, so that a small amount of tar that will be decomposed and condensed in the future can also stay in the form of adhesion between the packing layers. Finally, ensure that the organic matter in the crude gas is fully decomposed and attached here.

For organic matter such as tar attached to the packing layer after long-term operation, if the adhesion thickness is too large, the packing layer will be blocked and the decomposition effect will be affected. The outlet gas temperature of the pressurized fluidized bed gasifier is to make the tar in the organic decomposition device decompose rapidly and then return to the normal operating temperature, and the range of the outlet gas temperature is 50-100°C. By raising the temperature of the furnace gas for a short time, the decomposition of organic matter such as tar can be accelerated, so that the organic matter such as tar attached to the filler layer can be quickly decomposed, and because the time for raising the furnace temperature is short (usually no more than 15 minutes), it will not Affect the normal reaction operation in the pressurized fluidized bed gasifier. The water-cooled jacket fixed plate net can be fed with cooling water, and the cooling water is used to remove the heat of the fixed plate net under the radiation of high-temperature gas, so as to improve the service life of the fixed plate net.

Furthermore, the slag is an incompressible substance and does not have pressure itself. What has pressure is the gas contained in the gap between the slag and the slag. If it is discharged directly, the high temperature of the slag and the high pressure of the gas will cause the seal of the slag cooler to leak and get stuck. The slag temperature cannot be lowered, which leads to the problem of shutdown. In the utility model, while the temperature of the slag is lowered through the quenching chamber, the temperature of the mixed gas is also reduced at the same time, which has the function of decompression, thereby meeting the feeding requirements of the subsequent slag discharge and decompression device, and the temperature of the slag after quenching reaches 300-450°C, still contains a small amount of gas. At this time, the decompression tube can be used to decompress the solid slag containing a small amount of gas at a temperature of 300-350°C by reducing the diameter of the tube for the first time (preferably the tube in the reduced diameter section) The diameter is 10-50mm), the speed of the gas increases after decompression, and the equipment material is seriously worn. Therefore, the gas-containing high-speed solid slag is not suitable for further decompression with a decompression pipe, but a vent pipe is set under the decompression pipe, and the material (solid slag) after the first decompression passes through the vent pipe At this time, with the filtering effect of the filter layer in the pipe wall, the solid material continues to move in the pipe, and the entrained gas can pass through the filter layer and the annular cavity and be discharged out of the pipe through the air release valve, so as to reduce the pressure again. effect. The slagging decompression device including the decompression pipe and the air release pipe can be arranged in one group or in series as required to ensure the decompression effect.

Furthermore, the slag after reaction in the pressurized fluidized bed gasifier is chilled in the chilling chamber and then enters the material sealing bin for the following purposes: (1) Due to the high temperature of the slag, a large amount of steam can be generated by chilling, The steam generated by chilling rises directly into the furnace, which can reduce the amount of steam added in the fluidized bed gasifier, which is beneficial to energy saving and consumption reduction of the system; Requirements for temperature and pressure resistance, reducing the material cost of subsequent equipment and devices.

In the utility model, the pulverized coal is sent into the pressurized fluidized bed gasification furnace under the transmission of the pulverized coal sending tank by means of pneumatic conveying, and the way of conveying the pulverized coal by pneumatic force makes the entry of raw coal more stable and increases The temperature in the pressurized fluidized bed gasifier is easier to control.

In terms of further dry ash removal, the inventor specially selected a cyclone separator and a high-temperature filter (preferably a high-temperature fly ash filter) to cooperate with the dust removal method, and used the cyclone separator to remove large particles of dust in the crude gas (accounting for coarse The mass percentage of the total dust content in the gas is 65-80%), while the high-temperature filter has the characteristics of removing dust in various particle sizes, especially for dust particles with a particle size of less than 5 μm. The residual dust (very small amount of large particle dust and large amount of fine dust) in the crude gas after dedusting by the deduster is efficiently removed, so the final product gas (clean gas) contains very little dust (≤ 20mg/Nm ³ ), with Improved gas quality and recovered fly ash. This combination of two-stage dust removal not only has high dust removal efficiency, but also is the most optimized choice in terms of production volume, manufacturing cost and service life. Cyclone separators can be one, two or more in series, and the separated dry ash can be sent back to the lower section of the pressurized fluidized bed gasification furnace through a non-mechanical valve under the action of loose gas, and then participates in the gasification process in the furnace again. gasification reaction.

Beneficial effect:

(1) Pneumatically transporting pulverized coal can improve the problems of uneven feeding, easy blockage and leakage when the gasifier is running.

(2) By using the organic matter decomposition device, the organic matter such as tar, phenol, naphthalene, benzene and other by-products produced by the pressurized fluidized bed gasifier in the process of producing crude gas can be decomposed by increasing the residence time, so as to reduce the impact on such Reduce investment in material purification equipment, and reduce investment and consumption in subsequent washing water treatment;

(3) The high-temperature slag is processed through the combination of quenching water for preliminary cooling of the slag, further decompression of the decompression slag discharge device, and a slag cooler. Although the investment is higher than that of a slag cooler alone, it fundamentally solves the problem. The slag cooling machine is directly used to seal leakage and jamming, and the slag discharge temperature cannot be lowered to cause shutdown problems, ensuring the safe and stable operation of the system.

(4) Putting the waste heat boiler before the high-temperature fly ash filter can reduce the equipment and material investment of the high-temperature fly ash filter, and improve the purification effect of fly ash in the crude gas (dust content ≤ 20mg/Nm ³ ), and Dry fly ash can be obtained by using high temperature fly ash filter, which is beneficial to the environment and improves the economic benefit of the whole system at the same time. Taking a fluidized bed device with a coal processing capacity of 500,000 tons/year as an example, the waste water of the traditional normal pressure fluidized bed process is about 450,000 tons; if the new process of our invention is adopted, the waste water volume is only 80,000 tons. Calculated on the basis that the treatment cost of 1 ton of waste water containing tar, phenol and other organic substances is 25-33 yuan, the waste water treatment alone can save 9.25-12.2 million yuan per year, save 50 million yuan in equipment costs, obtain 10,000 tons of dry ash, and generate additional benefits of 2 million yuan Yuan.

(5) The system of the utility model is simple and the purification effect is good. The clean crude gas discharged from the top of the washing tower can be directly used in the downstream process without further treatment, which simplifies the process steps, further reduces the production cost, and shortens the production process. cycle.

Description of drawings

Fig. 1 process flow diagram and system diagram of the utility model.

Fig. 2 is a structural schematic diagram of the organic matter decomposition device of the present invention.

Figure 3 is a schematic structural view of the packing area.

Fig. 4 is a schematic diagram of a water-cooled jacket fixing an expanded metal.

Fig. 5 is a schematic structural view of the slag discharge decompression device.

Among them, 1-atmospheric coal bunker, 2-coal lock hopper, 3-coal powder sending tank, 4-organic matter decomposition device, 4.1-inlet, 4.2-exit, 4.3-filling area, 4.4-structured packing layer, 4.5-pass Hole, 4.6-Water-cooling jacket fixed plate net, 4.7-Cooling water inlet, 4.8-Cooling water outlet, 4.9-Cylinder, 5-Quenching chamber, 6-Material sealing bin, 7-Slagging pressure reducing device, 7.1- Pressure reducing pipe, 7.2-diameter reducing section, 7.3-venting pipe, 7.4-filter layer, 7.5-annular cavity, 7.6-outer pipe, 7.7-back blowing pipe, 7.8-venting valve, 8-decompression tank, 9- Slag cooler, 10-first-level cyclone dust collector, 11-second-level cyclone dust collector, 12-waste heat boiler, 13-ash collection tank, 14-ash lock bucket, 15-atmospheric pressure ash bin, 16-venturi, 17 - scrubber, 18 - pressurized fluidized bed gasifier, 19 - high temperature filter.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further explained:

Referring to Fig. 1, the normal pressure coal bunker 1 is connected with the coal powder inlet of the coal lock hopper 2, the pulverized coal delivery tank 3, and the pressurized fluidized bed gasifier 18 successively, and the reaction of the pressurized fluidized bed gasifier 18 is The gas outlet is connected with the air inlet of the organic matter decomposition device 4, the primary cyclone dust collector 10, the secondary cyclone dust collector 11, the waste heat boiler 12, and the high-temperature filter 19 in sequence, and the gas outlet of the high-temperature filter 12 is connected with the venturi in turn. 16. The washing tower 17 is connected; the slag outlet of the pressurized fluidized bed gasifier 18 is sequentially connected with the quenching chamber 5, the material sealing bin 6, the slag discharge decompression device 7, the decompression tank 8, and the slag cooler 9 The ash outlet of the first-stage cyclone dust collector 10 and the second-stage cyclone dust collector 11 is connected with the lower section of the pressurized fluidized bed gasifier 18 through a non-mechanical valve 20; the ash outlet of the high-temperature filter 19 is connected with the Ash collection tank 13, ash lock bucket 14, and normal pressure ash bin 15 are connected.

Referring to Fig. 2-Fig. 4, wherein, the organic matter decomposition device 4 comprises a cylinder 4.9 coated with a refractory paint layer, the diameter of the cylinder 4.9 is 6 to 10 times the diameter of the crude gas delivery pipeline, the cylinder 4.9 Both ends are provided with an inlet 4.1 and an outlet 4.2, and at least one packing area 4.3 (two packing areas 4.3 are provided in this embodiment) at intervals inside the cylinder 4.9, the packing area 4.3 includes multiple layers installed on a fixed plate The structured packing layer 4.4 in the net, the multi-layer structured packing layer 4.4 is staggered with through holes 4.5, the diameter of the through holes 4.5 is 50-100mm, and the distance L between each structured packing layer 4.4 is 600-1000mm . The fixed plate net is a water-cooled jacket fixed plate net 4.6 that can be fed into cooling water. The cooling water can flow in through the cooling water inlet 4.7 on the water-cooled jacket fixed plate net 4.6, and flow out through the cooling water outlet 4.8 after heat exchange.

Referring to Fig. 5, wherein, the slag discharge decompression device 7 includes a decompression pipe 7.1 and a vent pipe 7.3 located below the decompression pipe, the decompression pipe 7.1 has a diameter-reducing section 7.2, and the vent pipe 7.3 The pipe wall includes a filter layer 7.4, an annular cavity 7.5 and an outer pipe 7.6 from the inside to the outside. The annular cavity 7.5 communicates with the vent valve 7.8 and the blowback pipe 7.7. Design multiple groups in series, such as at least 2 groups in series in sequence.

crafting process:

The pulverized coal with a particle size of ≤8mm stored in the atmospheric coal bunker 1 is pressurized to 3.5-5.0MPa(G) through the coal lock hopper 2, and then sent through the pulverized coal under the action of the conveying gas by means of pneumatic conveyance The tank 3 sends the pulverized coal into the pressurized fluidized bed gasifier 18. The pulverized coal and the gasification agent in the furnace directly contact and react, forming a dense phase section in the upper part of the furnace, and a dilute phase section in the lower part. The temperature of the dense phase section is Evenly distributed, the reaction temperature in the gasifier is 950-1000°C, and the gasification pressure is 3.0-4.0MPa(G). The reacted slag falls to the bottom of the furnace and is quenched to 300-450°C by the cooling water fed into the quenching chamber 5, and then sent to the slag discharge decompression device 7 through the material sealing chamber 6, and the decompression pipe 7.1 is used to pass through the pipe diameter The reduction mode decompresses the cooled solid slag containing a small amount of gas for the first time (preferably the pipe diameter of the reduced diameter section 7.2 is 10-50mm), after decompression, the gas speed is accelerated, and it enters the vent pipe 7.3 with a larger pipe diameter , since the pipe wall of the vent pipe 7.3 has a filter layer 7.4, an annular cavity 7.5 and an outer pipe 7.6, and the vent valve 7.8 communicates with the annular cavity 7.5, when the vent valve 7.8 is opened, the gas containing slag in the solid slag can be filtered Layer 7.4 filters out the fine ash and discharges it through the annular cavity 7.5 and the vent valve 7.8, so as to achieve the purpose of reducing the pressure in the pipe and the flow rate of solid slag; when working for a long time, too much fine ash adheres to the surface of the filter layer 7.4, which will block the filter layer 7.4 In this case, the blowback gas is introduced into the annular cavity 7.5 through the short-term pressurization of the blowback pipe, so that the fine ash is shaken under the action of the blowback gas and the blowback pressure is released from the surface of the filter layer 7.4, preventing the filter layer 7.5 from Blockage affects the venting effect. The solid slag is decompressed once by the slag discharge decompression device 7, and then sent to the decompression tank 8 to continue decompression to below 0.2MPa(G), and finally cooled again by the slag cooler 9 and then discharged out of the system.

The reacted crude gas (containing dust) is first sent to the organic matter decomposition device 4 to decompose the organic matter contained in the gas. The crude gas enters the cylinder body 4.9 from the inlet 4.1, and passes through the multi-layered through holes 4.5 arranged in a staggered manner in the packing area 4.3. The structured packing layer 4.4, due to the thick diameter of the cylinder 4.9 and the special design of the packing area 4.3, can slow down the flow velocity of the crude gas in the cylinder 4.9, meeting the residence time required by the crude gas at high temperature (residence time is 3~15s), tar and other organic substances are decomposed by high temperature here, so as to achieve the purpose of removing impurities and reducing coke in the crude gas. The outlet gas temperature of the pressurized fluidized bed gasifier 18 is to quickly decompose the organic matter such as tar in the organic matter decomposition device 4 and then return to the normal operating temperature, and the range of increasing the outlet gas temperature is 50-100°C. The tar content in the crude gas can be reduced to less than 100ppm after the pyrolysis of tar and other organic matter contained in the organic matter decomposition device 4, and then sent to the waste heat boiler to cool down to 300-350°C after being dedusted by the two-stage cyclone dust collectors 10 and 11 , and then further dedusted by the high-temperature filter 19, the dust-removed crude gas passes through the Venturi 16 to agglomerate the fly ash in the gas, and then enters the scrubber ¹⁷ for washing. .

The dust collected by the first-stage cyclone dust collector 10 and the second-stage cyclone dust collector 11 in series returns to the lower section of the pressurized fluidized bed gasifier 18 by gravity through the non-mechanical valve 20 under the action of the loose gas, and then participates in the process again. Gasification reaction to increase the total carbon conversion rate and reduce the carbon content in fly ash.

The fly ash filtered by the high-temperature filter 19 is recovered through the ash collection tank 13 , the ash lock hopper 14 and the normal-pressure ash bin 15 .

The crude gas treated by the process of the utility model has a dust content of ≤1mg/Nm ³ , an organic matter content of less than 100ppm, a tar content of less than 100ppm, and a total carbon conversion rate of over 95%. The system has been in stable operation for 20 years.

Claims (10)

1. A pressurized fluidized bed system, comprising a pressurized fluidized bed, characterized in that, the reaction gas outlet of the pressurized fluidized bed gasifier is connected successively with an organic matter decomposition device, a cyclone dust collector, a waste heat boiler, a high temperature Filters and scrubbers. 2. The pressurized fluidized bed system as claimed in claim 1, wherein the organic matter decomposition device comprises a cylinder coated with a refractory paint layer, the two ends of the cylinder are provided with an inlet and an outlet, and the cylinder The interbody compartment is provided with at least one padding area. 3. The pressurized fluidized bed system according to claim 2, characterized in that the diameter of the cylinder is 6-10 times the diameter of the gas delivery pipeline. 4. The pressurized fluidized bed system as claimed in claim 2, characterized in that, the packing area comprises multi-layer structured packing layers installed in the fixed plate net, and the multi-layer structured packing layers are staggered with through holes. holes, the diameter of the through holes is 50-100mm, and the distance between each structured packing layer is 600-1000mm. 5 . The pressurized fluidized bed system according to claim 2 , wherein the fixed expanded metal is a water-cooled jacket fixed expanded metal that can be fed with cooling water. 6 . 6. The pressurized fluidized bed system according to any one of claims 1-5, characterized in that, the ash outlet of the pressurized fluidized bed gasifier is successively connected with the quenching chamber, the sealing bin, and the discharge chamber. Slag decompression device, decompression tank and slag cooling machine connection. 7. The pressurized fluidized bed system as claimed in claim 6, wherein the slag discharge decompression device comprises a decompression pipe and a vent pipe positioned below the decompression pipe, and the decompression pipe has a reduced diameter section, the pipe wall of the vent pipe includes a filter layer, an annular cavity and an outer pipe from the inside to the outside, and the annular cavity communicates with the vent valve. 8. The pressurized fluidized bed system according to claim 7, characterized in that, the annular cavity is also communicated with a blowback pipe. 9. The pressurized fluidized bed system according to claim 7 or 8, characterized in that there are at least two slag discharge decompression devices connected in series in sequence. 10. The pressurized fluidized bed system according to any one of claims 1-5, characterized in that the ash outlet of the cyclone dust collector is connected to the lower section of the pressurized fluidized bed gasifier through a non-mechanical valve .

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