Biomass gasification system and fluidized bed gasification process

Abstract

The invention provides a biomass gasification system and a fluidized bed gasification process, the system comprises a fluidized bed gasification furnace, a cyclone separator and a material returning leg, the fluidized bed gasification furnace is provided with a gasification cavity and a gas chamber, and a fluidized bed formed by bed materials is arranged in the gasification cavity. Bed materials are added into the gasification furnace in a spiral feeding and pneumatic conveying combined mode, a fluidized bed is established, biomass particles are added after temperature rise, the pressure in the gasification furnace is kept to be certain, and an auxiliary gasification agent enables the biomass particles to be in a fluidized state. According to the invention, the melting characteristic of biomass ash can be effectively improved, the problem of easy slag bonding during biomass gasification is solved, the gasification temperature is effectively increased, and the methane content in the synthesis gas is reduced. The bed material can catalytically crack tar generated in the biomass gasification process, the quality of synthesis gas is optimized, the synthesis gas is prevented from being bonded and attached to the metal wall of a downstream device, the yield of the synthesis gas and the stability of the device are improved, and the heat exchange efficiency of a downstream waste heat recovery unit is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass gasification, and in particular to a biomass gasification system and a fluidized bed gasification process. Background Art

[0002] The biomass gasification process cannot eliminate the problem of tar production. Tar is mainly produced by the partial oxidation of organic matter in biomass particles when there is insufficient oxygen supply, low temperature, or impurities that are difficult to completely burn. Tar is a complex mixture composed primarily of polycyclic aromatic hydrocarbons and heteroatom compounds.

[0003] During the operation of traditional biomass gasifiers, biomass slagging frequently occurs in the high-temperature reaction zone, seriously hindering the stable and efficient operation of the gasifier. Research has found that this is because the biomass is usually added to the gasifier first, followed by the catalyst, or the biomass and catalyst are added simultaneously. This causes the biomass to easily form slagging in the high-temperature reaction zone of the gasifier. The slagging will adhere to the inner wall of the gasifier, resulting in a decrease in the conversion rate of the gasifier, affecting the quality of the generated syngas, and can also cause blockage of channels such as the feed port, discharge port, air inlet, and outlet, as well as damage to the equipment. Summary of the Invention

[0004] The present invention aims to at least partially address one of the technical problems in the related art. To this end, embodiments of the present invention provide a biomass gasification system and a fluidized bed gasification process that can address the problem of slagging in the high-temperature reaction zone during biomass gasification.

[0005] In one aspect, an embodiment of the present invention proposes a biomass gasification system, comprising: a fluidized bed gasifier, a cyclone separator and a return leg. The fluidized bed gasifier has a gasification chamber and an air chamber. The gasification chamber is located above the air chamber. The gasification chamber has a fluidized bed formed by a bed material of catalytic cracking tar. The gasification chamber and the air chamber are separated by a distribution plate. The distribution plate is provided with a central hole and a plurality of air inlet holes. The air inlet holes connect the gasification chamber and the air chamber. The gasification chamber has a biomass inlet, a bed material inlet, an oxygen supply port, a return port, a slag drop port and a The discharge port, biomass inlet and bed material inlet are located above the distribution plate, and the slag outlet is located at the bottom of the fluidized bed gasifier. A slag outlet is connected between the center hole of the distribution plate and the slag outlet. The slag outlet runs through the gas chamber, and a gasifier air inlet pipe is inserted from bottom to top into the gasification chamber into the slag outlet. A gap is left between the gasifier air inlet pipe and the slag outlet pipe for slag dropping. The discharge port of the fluidized bed gasifier is located at the top of the gasification chamber; the side wall of the gas chamber has an auxiliary gasifier inlet to introduce an auxiliary gasifier into the gasification chamber for fluidizing the material.

[0006] The cyclone separator has a feed port, a discharge port and an air outlet. The feed port of the cyclone separator is connected to the discharge port of the fluidized bed gasifier, and the air outlet of the cyclone separator is connected to the waste heat recovery unit to pass the synthesis gas after gas-solid separation into the waste heat recovery unit to utilize the heat.

[0007] The return leg is connected between the return port of the fluidized bed gasifier and the discharge port of the cyclone separator to return the materials carried by the synthesis gas to the fluidized bed gasifier for further reaction.

[0008] In some embodiments, the biomass gasification system further includes a tail gas purification device, which is connected to the exhaust port of the waste heat recovery unit to filter and purify the synthesis gas.

[0009] In some embodiments, the exhaust gas purification device includes a filter and a water scrubber, and the filter is connected between the exhaust port of the waste heat recovery unit and the air inlet of the water scrubber.

[0010] In some embodiments, the bed material inlet of the fluidized bed gasifier is connected to a feeding mechanism, which includes a bed material hopper, a rotary feeder and a feeding pipe. The rotary feeder is connected to the discharge port of the bed material hopper. The feeding pipe has a first end and a second end along the axial direction. The first end of the feeding pipe is connected to the bed material inlet of the fluidized bed gasifier, and the second end of the feeding pipe is connected to the rotary feeder. The feeding pipe is provided with an air inlet near the second end, and the air inlet of the feeding pipe is connected to a pneumatic conveying device to cooperate with the rotary feeder to pneumatically convey the bed material into the gasification chamber.

[0011] In some embodiments, the rotary feeder is connected to a flow control device and an intelligent control system to regulate the delivery amount of the bed material.

[0012] In some embodiments, the bed material hopper includes a bed material bin, a bed material lock hopper and a bed material sending hopper. The discharge port of the bed material bin is connected to the feed port of the bed material lock hopper, the discharge port of the bed material lock hopper is connected to the feed port of the bed material sending hopper, and the rotary feeder is connected to the discharge port of the bed material sending hopper.

[0013] In some embodiments, the distribution plate has a funnel-shaped structure.

[0014] In some embodiments, the feed pipe is provided with a protective gas inlet near the first end of the feed pipe, so as to introduce protective gas into the gasification chamber during the gasification of the biomass particles.

[0015] Another embodiment of the present invention provides a fluidized bed gasification process, utilizing the above-mentioned biomass gasification system, comprising the following steps:

[0016] Bed material is added to the gasifier by combining spiral feeding with pneumatic conveying to establish a fluidized bed. After heating to 800-900℃, biomass particles are added. The pressure in the gasifier is maintained at 0.85-1.0Mpa. The auxiliary gasifier makes the biomass particles form a fluidized state. During the gasification process of the biomass particles, the gasifier is added through the gasifier inlet pipe.

[0017] The fly ash generated after the biomass particles are gasified enters the cyclone separator with the pressurized air flow for gas-solid separation to obtain solid material and synthesis gas. The solid material is returned to the gasification chamber through the return leg for cyclic gasification, and the synthesis gas is passed into the waste heat recovery unit to utilize the heat. After heat exchange, the synthesis gas is successively passed into the filter and water washing tower for filtration and purification, and finally collected.

[0018] In some embodiments, the bed material includes a mixture of one or more of calcium oxide, magnesium oxide, iron oxide, and aluminum oxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0020] in:

[0021] Figure 1 Schematic diagram of the structure of the biomass gasification system in an embodiment of the present invention;

[0022] Reference numerals:

[0023] 1. Bed material bin; 2. Bed material lock hopper; 3. Bed material sending hopper; 4. Rotary feeder; 5. Feed pipe; 6. Air chamber; 7. Gasification agent inlet pipe; 8. Gasification chamber; 9. Return leg; 10. Distribution plate; 11. Slag drop pipe; 12. Cyclone separator; 13. Waste heat recovery unit; 14. Filter; 15. Water scrubber. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0025] The following describes a biomass gasification system and a fluidized bed gasification process according to embodiments of the present invention with reference to the accompanying drawings.

[0026] like Figure 1As shown, an embodiment of the present invention proposes a biomass gasification system, including: a fluidized bed gasifier, a cyclone separator 12 and a return leg 9, the fluidized bed gasifier has a gasification chamber 8 and an air chamber 6, the gasification chamber 8 is located above the air chamber 6, the gasification chamber 8 has a fluidized bed formed by a bed material of catalytic cracking tar, the gasification chamber 8 and the air chamber 6 are separated by a distribution plate 10, the distribution plate 10 is provided with a central hole and a plurality of air inlet holes, the air inlet holes connect the gasification chamber 8 with the air chamber 6, the gasification chamber 8 has a biomass inlet, a bed material inlet, an oxygen supply port, a return port, a slag drop port and an outlet The material inlet, biomass inlet and bed material inlet are located above the distribution plate 10, and the slag outlet is located at the bottom of the fluidized bed gasifier. A slag outlet is connected between the center hole of the distribution plate 10 and the slag outlet. The slag outlet 11 passes through the gas chamber 6. The gasifier air inlet pipe 7 is inserted from bottom to top into the gasification chamber 8 into the slag outlet 11. A gap is left between the gasifier air inlet pipe 7 and the slag outlet 11 for slag dropping. The material outlet of the fluidized bed gasifier is located at the top of the gasification chamber 8; the side wall of the gas chamber 6 has an auxiliary gasifier inlet to introduce an auxiliary gasifier into the gasification chamber 8 for fluidizing the material.

[0027] The cyclone separator 12 has a feed port, a discharge port and an air outlet. The feed port of the cyclone separator 12 is connected to the discharge port of the fluidized bed gasifier, and the air outlet of the cyclone separator 12 is connected to the waste heat recovery unit 13 to pass the synthesis gas after gas-solid separation into the waste heat recovery unit 13 to utilize the heat.

[0028] The return leg 9 is connected between the return port of the fluidized bed gasifier and the discharge port of the cyclone separator 12 to return the materials carried by the synthesis gas to the fluidized bed gasifier for further reaction.

[0029] The embodiment of the present invention provides a fluidized bed gasifier, a cyclone separator 12 and a return leg 9, and pre-arranges a fluidized bed formed by bed material in the fluidized bed gasifier, which can effectively improve the melting characteristics of biomass ash and solve the problem of easy slagging of biomass in the high-temperature reaction zone of the gasifier. At the same time, the bed material has a catalytic effect and can catalytically crack the tar produced during the biomass gasification process, thereby increasing the proportion of carbon monoxide and hydrogen in the generated synthesis gas and optimizing the quality of the synthesis gas.

[0030] By adding bed material in advance, the synthesis gas produced by gasification can be made cleaner, the tar content can be reduced, and adhesion and adhesion to the metal walls of downstream devices (such as the waste heat recovery unit 13) can be avoided, thereby improving the synthesis gas yield and the stability of the device and enhancing the heat exchange efficiency of the downstream waste heat recovery unit 13.

[0031] The auxiliary gasification agent inlet is used to introduce an auxiliary gasification agent, primarily water vapor. This agent causes the biomass particles and bed material to float upward through the airflow, then fall downward through their own weight, repeatedly creating a fluidized state. The auxiliary gasification agent also contains a small amount of oxygen, which provides a sufficient supply of oxygen for the gasification process.

[0032] Furthermore, the upper end surface of the gasifying agent inlet pipe 7 is located at or below the center hole of the distribution plate 10. Since the inlet pressure of the gasifying agent inlet pipe 7 is relatively high, the problem of ash clogging the gasifying agent inlet pipe 7 will not occur.

[0033] Furthermore, an oxygen inlet is located in the low-temperature zone at the top of gasification chamber 8, providing oxygen and regulating the temperature during the biomass gasification process. Because some biomass is blown from the high-temperature reaction zone at the bottom of the gasifier to the low-temperature zone above, the oxygen content in this zone is theoretically close to zero. Therefore, oxygen supplementation is required to continue the reaction, thereby improving gasification efficiency.

[0034] Furthermore, the air inlet holes of the distribution plate 10 are evenly distributed on the distribution plate 10 to ensure the uniformity of the gasification agent intake.

[0035] Furthermore, a control valve is connected to the gasifying agent inlet pipe 7. When the gasifying agent is not needed, the control valve is closed to prevent ash from entering the source of the gasifying agent or the air pump through the gasifying agent inlet pipe 7, thereby contaminating the gasifying agent or damaging the equipment.

[0036] In some embodiments, the biomass gasification system further includes a tail gas purification device, which is connected to the exhaust port of the waste heat recovery unit 13 to filter and purify the synthesis gas.

[0037] In some embodiments, the exhaust gas purification device includes a filter 14 and a water scrubber 15 , and the filter 14 is connected between the exhaust port of the waste heat recovery unit 13 and the air inlet of the water scrubber 15 .

[0038] In some embodiments, the bed material inlet of the fluidized bed gasifier is connected to a feeding mechanism, which includes a bed hopper, a rotary feeder 4 and a feeding pipe 5. The rotary feeder 4 is connected to the discharge port of the bed hopper, and the feeding pipe 5 has a first end and a second end along the axial direction. The first end of the feeding pipe 5 is connected to the bed material inlet of the fluidized bed gasifier, and the second end of the feeding pipe 5 is connected to the rotary feeder 4. The feeding pipe 5 is provided with an air inlet near the second end, and the air inlet of the feeding pipe 5 is connected to a pneumatic conveying device to cooperate with the rotary feeder 4 to pneumatically convey the bed material into the gasification chamber 8.

[0039] The bed material feeding mechanism of the present invention accurately and stably delivers bed material into the gasifier. The use of a rotary feeder 4 allows for controlled bed material delivery and speed, while also being compact and leak-tight. Pneumatically conveying the bed material, the bed material is sprayed into the gasification chamber 8. Due to the airflow of the auxiliary gasifying agent, the bed material is lifted a short distance before falling back under its own weight, creating a circulation pattern that ensures uniform distribution of the bed material within the gasification chamber 8.

[0040] Furthermore, the gas source transported by the pneumatic conveying device is nitrogen or carbon dioxide.

[0041] Furthermore, the feed pipe 5 is tilted, and the height of the first end of the feed pipe 5 is greater than the height of the second end. In combination with the air pressure of the conveying gas, the feed pipe 5 can be prevented from being blocked.

[0042] In some embodiments, the rotary feeder 4 is connected to a flow control device and an intelligent control system to regulate the bed material delivery rate. The bed material delivery rate can be automatically and accurately adjusted based on different biomass types, processing volume, and gasification conditions. Furthermore, the intelligent control system can dynamically adjust the timing of bed material replenishment based on real-time parameters such as gasifier temperature, pressure, and biomass feed rate to maintain the fluidized bed height.

[0043] In some embodiments, the bed material hopper includes a bed material bin 1, a bed material locking hopper 2 and a bed material sending hopper 3. The discharge port of the bed material bin 1 is connected to the feed port of the bed material locking hopper 2, the discharge port of the bed material locking hopper 2 is connected to the feed port of the bed material sending hopper 3, and the rotary feeder 4 is connected to the discharge port of the bed material sending hopper 3.

[0044] The bed material hopper 1 is used to store bed material, and the bed material lock hopper 2 is used to switch between high-pressure and low-pressure conditions, thereby feeding the low-pressure bed material into the high-pressure bed material delivery hopper 3. The bed material lock hopper 2 acts as a bridge. The bed material delivery hopper 3 is used to pneumatically transport the bed material into the gasifier.

[0045] In some embodiments, the distribution plate 10 is in a funnel-shaped structure, so that the ash produced by the reaction can be discharged through the ash drop pipe 11 .

[0046] In some embodiments, the feed pipe 5 is provided with a protective gas inlet near the first end of the feed pipe 5 so as to introduce protective gas into the gasification chamber 8 during the gasification process of the biomass particles.

[0047] Furthermore, the protective gas is nitrogen or carbon dioxide.

[0048] like Figure 1 As shown, another embodiment of the present invention provides a fluidized bed gasification process, which utilizes the above-mentioned biomass gasification system and includes the following steps:

[0049] Bed material is added to the gasifier by combining spiral feeding with pneumatic conveying to establish a fluidized bed. After heating to 800-900℃, biomass particles are added. The pressure in the gasifier is maintained at 0.85-1.0Mpa. The auxiliary gasifier makes the biomass particles form a fluidized state. During the gasification process of the biomass particles, the gasifier is added through the gasifier inlet pipe.

[0050] The fly ash generated after the biomass particles are gasified enters the cyclone separator 12 with the pressurized air flow for gas-solid separation to obtain solid material and synthesis gas. The solid material is returned to the gasification chamber 8 through the return leg 9 for cyclic gasification, and the synthesis gas is passed into the waste heat recovery unit 13 to utilize the heat. The synthesis gas after heat exchange is sequentially passed into the filter 14 and the water washing tower 15 for filtration and purification, and finally collected.

[0051] In the embodiment of the present invention, by first arranging bed material in the gasifier to form a fluidized bed, and then introducing biomass for gasification, the melting characteristics of biomass ash can be effectively improved, the problem of easy slagging during biomass gasification can be solved, the gasification temperature can be effectively increased, and the methane content in the synthesis gas can be reduced. At the same time, the bed material also has a certain catalytic effect, which can catalytically crack the tar produced during the biomass gasification process and optimize the quality of the synthesis gas.

[0052] It should be noted that the gasifier's feed port, gasifying agent inlet, and auxiliary gasifying agent inlet are all pressurized when introducing gas into the gasifier. Maintaining the gas pressure in the gasifier between 0.85-1.0 MPa ensures that the material in the gasifier can be recycled and the fly ash formed during the biomass gasification process can be completely gasified. Moreover, since it can be recycled, the equipment size can be reduced while ensuring that the output remains unchanged, thereby reducing the equipment's footprint. Traditional atmospheric circulating fluidized bed reactors find it difficult to completely gasify high-carbon fly ash through high-rate recycling, and the fly ash can only be sent out for treatment.

[0053] In some embodiments, the bed material includes a mixture of one or more of calcium oxide, magnesium oxide, iron oxide, and aluminum oxide.

[0054] The presence of tar in the syngas produced by biomass gasification reduces its quality and increases subsequent purification costs. The bed material used in this invention exhibits excellent catalytic activity, reducing tar production by over 50%. Under the gasification reaction environment, these metal oxides can disrupt the chemical bonds of tar macromolecules, lowering the activation energy required for tar cracking reactions and promoting the rapid decomposition of tar into small gas molecules. This significantly reduces the tar content in the syngas and alleviates the workload of subsequent purification steps.

[0055] This bed material undergoes a series of complex and critical physical and chemical reactions with the biomass ash. In a pilot test, adding a bed material that accounts for approximately 10% of the mass of biomass particles can increase the ash melting temperature by approximately 100°C. From a physical perspective, the bed material is dispersed in the ash, changing the way the ash particles interact with each other, thereby affecting its viscosity. Chemically, the bed material reacts with certain components in the ash, causing the chemical composition of the ash to change, ultimately successfully lowering the melting point of the ash. This dual mechanism of action effectively avoids excessive melting of the ash at high temperatures, greatly reducing the occurrence of slagging and providing a solid guarantee for the continuous and stable operation of the gasifier at high temperatures.

[0056] Furthermore, the selection of bed materials is not limited to these four metal oxides, and there is no restriction on the ratio between the metal oxides.

[0057] The following experiment compares the final syngas content collected using the bed material of an embodiment of the present invention and a conventional quartz sand bed material. Aside from the different bed materials, all other methods and parameters were identical. The bed material used in the embodiment of the present invention was a mixture of calcium oxide, magnesium oxide, iron oxide, and aluminum oxide.

[0058] Table 1 shows the content of the syngas finally collected using the bed material of the embodiment of the present invention and the traditional quartz sand bed material.

[0059] Table 1

[0060] Project (Unit) Bed material according to the embodiment of the present invention Traditional quartz sand bed material <![CDATA[H2(Mol.%)]]> 29.895 26.570 CO (Mol.%) 28.306 27.826 <![CDATA[CO2(Mol.%)]]> 18.990 19.590 <![CDATA[CH4(Mol.%)]]> 4.45 6.762 <![CDATA[N2(Mol.%)]]> 0.315 0.445 Ar (Mol.%) 0.051 0.053 <![CDATA[NH3(Mol.%)]]> 0.258 0.271 <![CDATA[H2S(Mol.%)]]> 0.045 0.045 COS (Mol.%) 0.00043 0.00046 HCl (Mol.%) trace amount trace amount <![CDATA[H2O(Mol.%)]]> 17.690 17.981 <![CDATA[Tar (mg / Nm 3 )]]> 85 4750 Total (Mol.%) 100.0 100.0

[0061] As can be seen from Table 1, by using the bed material according to the embodiment of the present invention, the contents of tar and methane in the syngas produced are significantly reduced, and the contents of hydrogen and carbon monoxide in the syngas are increased.

[0062] In the present invention, the term "some embodiments" and the like means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in any one or more embodiments. In addition, those skilled in the art may combine and combine the different embodiments and features of different embodiments described in this specification unless they are mutually inconsistent.

[0063] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A biomass gasification system, characterized in that: include: A fluidized bed gasifier, wherein the fluidized bed gasifier has a gasification chamber and an air chamber, wherein the gasification chamber is located above the air chamber, wherein the gasification chamber has a fluidized bed formed by a bed material acted upon by catalytic cracking tar, wherein the gasification chamber and the air chamber are separated by a distribution plate, wherein a central hole and a plurality of air inlet holes are provided on the distribution plate, wherein the air inlet holes connect the gasification chamber with the air chamber, wherein the gasification chamber has a biomass inlet, a bed material inlet, an oxygen supply port, a return port, a slag drop port and a discharge port, wherein the biomass inlet and the bed material inlet are located on the distribution plate. Above the distribution plate, the slag drop port is located at the bottom of the fluidized bed gasifier. A slag drop pipe is connected between the central hole of the distribution plate and the slag drop port. The slag drop pipe penetrates the gas chamber. A gasifying agent inlet pipe is inserted into the slag drop pipe from bottom to top into the gasification chamber. A gap for slag drop is left between the gasifying agent inlet pipe and the slag drop pipe. The discharge port of the fluidized bed gasifier is located at the top of the gasification chamber. The side wall of the gas chamber has an auxiliary gasifying agent inlet for introducing an auxiliary gasifying agent into the gasification chamber for fluidizing the material. A cyclone separator, the cyclone separator having a feed inlet, a discharge port, and an air outlet, the feed inlet of the cyclone separator being connected to the discharge port of the fluidized bed gasifier, and the air outlet of the cyclone separator being connected to a waste heat recovery unit, so as to pass the synthesis gas after gas-solid separation into the waste heat recovery unit for heat utilization; A return leg is connected between the return port of the fluidized bed gasifier and the discharge port of the cyclone separator to return the material carried by the synthesis gas to the fluidized bed gasifier for continued reaction.

2. The biomass gasification system according to claim 1, characterized in that: It also includes an exhaust gas purification device, which is connected to the exhaust port of the waste heat recovery unit to filter and purify the synthesis gas.

3. The biomass gasification system according to claim 2, characterized in that: The tail gas purification device includes a filter and a water scrubber, and the filter is connected between the exhaust port of the waste heat recovery unit and the air inlet of the water scrubber.

4. The biomass gasification system according to claim 1, characterized in that: The bed material inlet of the fluidized bed gasifier is connected to a feeding mechanism, and the feeding mechanism includes a bed material hopper, a rotary feeder and a feeding pipe. The rotary feeder is connected to the discharge port of the bed material hopper. The feeding pipe has a first end and a second end along the axial direction. The first end of the feeding pipe is connected to the bed material inlet of the fluidized bed gasifier, and the second end of the feeding pipe is connected to the rotary feeder. The feeding pipe is provided with an air inlet at a position near the second end, and the air inlet of the feeding pipe is connected to a pneumatic conveying device to cooperate with the rotary feeder to deliver the bed material into the gasification chamber by pneumatic conveying.

5. The biomass gasification system according to claim 4, characterized in that: The rotary feeder is connected to a flow control device and an intelligent control system to regulate the delivery amount of the bed material.

6. The biomass gasification system according to claim 4, characterized in that: The bed material hopper includes a bed material bin, a bed material locking hopper and a bed material sending hopper. The discharge port of the bed material bin is connected to the feed port of the bed material locking hopper, the discharge port of the bed material locking hopper is connected to the feed port of the bed material sending hopper, and the rotary feeder is connected to the discharge port of the bed material sending hopper.

7. The biomass gasification system according to claim 1, characterized in that: The distribution plate is in a funnel-shaped structure.

8. The biomass gasification system according to claim 4, characterized in that: The feed pipe is provided with a protective gas inlet at a position close to the first end of the feed pipe, so as to introduce protective gas into the gasification chamber during the gasification process of the biomass particles.

9. A fluidized bed gasification process, characterized in that: The biomass gasification system according to any one of claims 1 to 8 comprises the following steps: Adding bed material into the gasifier by combining screw feeding and pneumatic conveying to establish a fluidized bed, heating to 800-900°C and adding biomass particles, maintaining the pressure in the gasifier at 0.85-1.0 MPa, and supplementing the gasification agent to fluidize the biomass particles. During the gasification of the biomass particles, the gasification agent is added through the gasification agent inlet pipe; The fly ash generated after the biomass particles are gasified enters the cyclone separator with the pressurized air flow for gas-solid separation to obtain solid material and synthesis gas. The solid material is returned to the gasification chamber through the return leg for cyclic gasification, and the synthesis gas is passed into the waste heat recovery unit to utilize the heat. After heat exchange, the synthesis gas is successively passed into the filter and water washing tower for filtration and purification, and finally collected.

10. The fluidized bed gasification process according to claim 9, characterized in that: The bed material includes a mixture of one or more of calcium oxide, magnesium oxide, iron oxide, and aluminum oxide.

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