Method and device for preparing synthesis gas through biomass grading gasification

Abstract

The invention provides a method and device for preparing synthesis gas through biomass graded gasification, and belongs to the technical field of biomass gasification. The method for preparing synthesis gas through biomass graded gasification comprises the steps that biomass fuel and a first gasification agent or carrier gas are introduced into a first fluidized bed reactor, volatile components in the biomass fuel are extracted through a pyrolytic reaction or a partial gasification reaction, and a tar-containing gas-solid mixture and semicoke particles are generated; separating the tar-containing gas-solid mixture by a first gas-solid separator to obtain tar-containing mixed gas and solid particles with first particle size; and conveying the tar-containing mixed gas and a third gasifying agent into a downer reactor, and carrying out thermal cracking on tar in the tar-containing mixed gas through a thermal cracking reaction to generate tar-free synthesis gas.

Description

Technical Field

[0001] This disclosure belongs to the field of biomass gasification technology, and particularly relates to a method and apparatus for preparing syngas by staged biomass gasification. Background Technology

[0002] Biomass gasification is an important way to utilize biomass cleanly and efficiently. Through gasification, biomass can be efficiently and cleanly converted into syngas, which can then be used to produce green hydrogen and bulk chemicals such as methanol, fuel ethanol, and bio-kerosene. These chemicals can be used as fuels in the transportation sector, replacing fossil fuels while reducing carbon dioxide emissions.

[0003] The mainstream technologies for biomass gasification include fixed-bed gasification and fluidized-bed gasification. However, neither fixed-bed nor fluidized-bed gasification has been widely applied in the field of biomass gasification for producing green chemicals. At the same time, the following key problems exist, such as: 1) high tar content in syngas, which affects the stable operation of the plant; 2) poor adaptability of feedstock and poor operational stability; 3) complex process and high cost.

[0004] Therefore, there is an urgent need to develop clean, efficient, low-cost, widely adaptable to fuels, and stable biomass gasification technologies that can operate stably for long periods. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure provides a method and apparatus for preparing syngas from biomass through staged gasification, aiming to at least partially solve these problems. The specific technical solution provided by this disclosure is as follows.

[0006] As a first aspect of this disclosure, a method for preparing syngas from biomass through staged gasification is provided, comprising:

[0007] Biomass fuel and a first gasifying agent or carrier gas are introduced into a first fluidized bed reactor, where volatiles are extracted from the biomass fuel through pyrolysis or partial gasification to produce a tar-containing gas-solid mixture and semi-coke particles.

[0008] After the tar-containing gas-solid mixture is separated by the first gas-solid separator, a tar-containing mixed gas and solid particles of the first particle size are obtained.

[0009] A tar-containing mixed gas and a third gasifying agent are transported to a downward bed reactor, where the tar in the tar-containing mixed gas is thermally decomposed through a thermal cracking reaction to produce tar-free syngas.

[0010] As a second aspect of this disclosure, an apparatus for preparing syngas by staged gasification of biomass is provided, comprising: a first fluidized bed reactor, a first gas-solid separator and a downflow bed reactor connected in sequence;

[0011] The first fluidized bed reactor is equipped with a biomass fuel inlet, a first gasifying agent or carrier gas inlet, a first gasification product outlet for discharging a tar-containing gas-solid mixture, and a semi-coke outlet for discharging semi-coke particles.

[0012] The first gas-solid separator is provided with a first gas-solid mixture inlet connected to the first gasification product outlet, and a first gas outlet and a first solid outlet for discharging the tar-containing mixed gas and the first-size solid particles obtained after gas-solid separation, respectively; and

[0013] The downflow bed reactor is equipped with a downflow bed reactor gas inlet connected to the first gas outlet of the first gas-solid separator, a third gasifying agent inlet, and a syngas outlet for discharging tar from the tar-containing mixed gas through thermal cracking reaction to produce tar-free syngas.

[0014] Based on the above technical solution, the method and apparatus for preparing syngas by staged gasification of biomass disclosed in this disclosure have at least one of the following beneficial effects:

[0015] (1) In the embodiments of this disclosure, biomass fuel is fed into a first fluidized bed reactor for pyrolysis or partial gasification to extract volatiles from the biomass, producing a gas with high tar and methane content, i.e., a tar-containing gas-solid mixture. After separation by a first gas-solid separator, the tar-containing gas-solid mixture is then fed into a downflow bed reactor for thermal cracking to decompose the tar and methane in the tar-containing gas mixture, obtaining tar-free syngas. This solves the problem of unstable operation of the device due to high tar content in traditional processes. At the same time, through the synergistic effect of pyrolysis or partial gasification in the first fluidized bed reactor and thermal cracking in the downflow bed reactor, tar in the syngas is removed, improving the quality of the syngas, enabling the gasification system to operate normally, and reducing the cost of producing higher quality syngas.

[0016] (2) In the embodiments of this disclosure, by using the first fluidized bed reactor and the downflow bed reactor in combination, the size of the cracking reactor (i.e. the downflow bed reactor) is reduced by staged gasification, which greatly reduces the investment in the gasification to produce syngas and increases the economic efficiency of operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the process for preparing syngas from biomass through staged gasification in the first embodiment of this disclosure;

[0018] Figure 2 This is a schematic diagram of the process for preparing syngas from biomass staged gasification in the second embodiment of this disclosure;

[0019] Figure 3This is a schematic diagram of a downflow bed reactor used in the staged gasification of biomass to prepare syngas in the third embodiment of this disclosure.

[0020] Explanation of reference numerals in the attached figures

[0021] A - Biomass fuel, B0 - Carrier gas, B1 - First gasifying agent, B2 - Second gasifying agent, B3 - Third gasifying agent, C - Tar-containing gas-solid mixture, D - First particle size solid particles, E - Tar-containing mixed gas, F - Tar-free gas-solid mixture, G - Tar-free syngas, H - Second particle size solid particles, I - Bottom ash, J - Semi-coke particles, K - Ash;

[0022] 1-First fluidized bed reactor, 2-Second fluidized bed reactor, 3-Downflow bed reactor, 4-First gas-solid separator, 5-Second gas-solid separator;

[0023] 1a-Biomass fuel inlet, 1b-Inlet of the first gasifying agent or carrier gas, 1c-Outlet of the first gasification product, 1d-Semi-coke outlet;

[0024] 2a-First solid particulate matter inlet, 2b-Second gasifying agent inlet, 2c-Second gasification product outlet, 2d-Bottom ash outlet, 2e-Second solid particulate matter inlet, 2f-Gasifying agent nozzle;

[0025] 3a-Cracked gas channel, 3b-Gasifying agent nozzle, 3c-Synthesis gas outlet, 3d-Gas-solid burner unit, 3e-Ash and slag outlet, 3f-Material inlet of the descending bed reactor, 3a1-Gas inlet of the descending bed reactor, 3b1-Third gasifying agent inlet, 3d1-First channel, 3d2-Second channel. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of this disclosure will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0027] The mainstream biomass gasification technologies include fixed-bed gasification and fluidized-bed gasification. Fixed-bed gasification produces syngas with a high tar content, primarily used to produce fuel gas, and is widely applied in biomass gasification power generation. Fluidized-bed gasification offers better mass and heat transfer, resulting in more uniform furnace temperatures. The circulation of semi-coke during gasification can promote tar cracking to some extent. However, due to the generally low ash melting point of biomass, the operating temperature of the gasifier is typically controlled between 700℃ and 850℃, while the effective cracking temperature of tar is above 1000℃. This means that traditional fluidized-bed gasification technology cannot effectively solve the tar problem. Furthermore, both fixed-bed and fluidized-bed gasification technologies suffer from high tar content in the syngas, which can clog pipelines and equipment, preventing the gasification system from operating normally and affecting the quality of the syngas produced. To achieve higher carbon conversion rates, relatively high gasification temperatures are required. However, biomass has a high alkali metal content, and high-temperature operation (above 1000℃) easily leads to slagging in the furnace, restricting long-term stable operation of the unit and resulting in poor feedstock adaptability. In addition, the high methane content in the syngas necessitates the separation of methane to meet downstream synthesis demands, which increases the complexity of the process and raises costs.

[0028] To address the aforementioned issues, this disclosure provides a method and apparatus for preparing syngas from biomass through staged gasification. By using staged gasification, the tar and methane content in the syngas is reduced, solving the problem of high tar and methane content in biomass gasification. By staged gasification of the semi-coke particles after volatile matter extraction, tar-free syngas is obtained while avoiding slagging of the semi-coke particles in the furnace, which would affect the long-term operational stability of the apparatus, thus broadening the adaptability of biomass feedstocks.

[0029] Figure 1 This is a schematic diagram of the process for preparing syngas from biomass through staged gasification in the first embodiment of this disclosure.

[0030] Combination Figure 1 This document provides a detailed description of a method for preparing syngas from biomass through staged gasification, as described in the embodiments of this disclosure.

[0031] As a first embodiment of the first aspect of this disclosure, this disclosure provides a method for preparing syngas by staged gasification of biomass, comprising: introducing biomass fuel A and a first gasifying agent B1 or carrier gas B0 into a first fluidized bed reactor 1, extracting volatiles from biomass fuel A through pyrolysis or partial gasification reaction to produce a tar-containing gas-solid mixture C and semi-coke particles J; separating the tar-containing gas-solid mixture C through a first gas-solid separator 4 to obtain a tar-containing mixed gas E and solid particles of a first particle size D; conveying the tar-containing mixed gas E and a third gasifying agent B3 into a downflow bed reactor 3, thermally cracking the tar in the tar-containing mixed gas E to produce tar-free syngas G.

[0032] In the embodiments of this disclosure, biomass fuel A is fed into a first fluidized bed reactor 1 for pyrolysis or partial gasification to extract volatiles from the biomass, producing a gas with high tar and methane content, namely a tar-containing gas-solid mixture C. This tar-containing gas-solid mixture C is then separated by a first gas-solid separator 4 and fed into a descending bed reactor 3 for thermal cracking to remove tar and methane, yielding tar-free syngas G. This solves the problem of unstable operation of the equipment due to high tar content in traditional processes.

[0033] In the first embodiment of this disclosure, biomass fuel A includes forestry biomass or agricultural biomass. Forestry biomass includes any one of branches, bark, and waste wood, while agricultural biomass includes any one of corn stalks, wheat stalks, rice stalks, and cotton stalks. Other biomass fuels can also be used; this is merely an example and no further specific limitations are made. When partial gasification occurs in the first fluidized bed reactor 1, a first gasifying agent B1 is introduced into the first fluidized bed reactor 1. The first gasifying agent B1 is a mixture of oxygen and water vapor or carbon dioxide. In the first gasifying agent B1, the molar ratio of oxygen to water vapor or carbon dioxide is 0.3-0.5. If the molar ratio is too low, the effective gas (CO+H2) component will decrease; if the molar ratio is too high, it will easily lead to slagging of semi-coke particles J, affecting the operational stability of the first fluidized bed reactor 1. When a pyrolysis reaction occurs in the first fluidized bed reactor 1, a carrier gas B0, which can be either nitrogen or carbon dioxide, is introduced into the first fluidized bed reactor 1. An external heating method is used as the heat source for the reaction in the first fluidized bed reactor 1; for example, green electricity or hot flue gas can be used to heat the first fluidized bed reactor 1. When the feed rate of biomass fuel A is constant, the reaction temperature and the degree of gasification or pyrolysis reaction in the first fluidized bed reactor 1 are controlled by controlling the flow rate of the first gasifying agent B1 or the carrier gas B0. Similarly, the degree of gasification reaction and the reaction temperature in the lower fluidized bed reactor 3 are controlled by controlling the flow rate of the third gasifying agent B3. Depending on the type of biomass fuel A, the operating temperature design principle for the first fluidized bed reactor 1 and the downflow bed reactor 3 is as follows: the first fluidized bed reactor 1 should achieve an ash and volatile matter removal rate of greater than 90% in biomass fuel A. If the volatile matter removal rate in the first fluidized bed reactor 1 is too low, the tar and methane content in the syngas produced after gasification reaction in the downflow bed reactor 3 and the second fluidized bed reactor 2 in subsequent embodiments will be too high, resulting in the syngas (i.e., product gas) not meeting chemical requirements. If the gasification reaction fraction in the first fluidized bed reactor 1 is too high, the amount of gas entering the downflow bed reactor 3 will increase, leading to an increase in the size of the downflow bed reactor 3 and increased equipment investment. Therefore, in the first embodiment of this disclosure, the temperature in the first fluidized bed reactor 1 is controlled by controlling the amount of the first gasifying agent B1 or the carrier gas B0, thereby controlling the extraction amount of volatile matter in biomass fuel A and the processing load of the tar-containing mixed gas E in the downflow bed reactor 3. The reaction in the first fluidized bed reactor 1 is at 450-650℃. Within this temperature range, the volatiles in biomass fuel A can be fully extracted, while avoiding slagging of biomass fuel A due to excessively high reaction temperature, and avoiding an increase in the load due to increased gas volume in the downward flow bed reactor 3.The third gasifying agent B3 is selected from oxygen or a mixture of oxygen and water vapor, with a molar ratio of oxygen to water vapor of 0.6-0.9. By controlling the amount of the third gasifying agent B3 entering the downward bed reactor 3, the reaction temperature of the downward bed reactor 3 is controlled at 900-1400℃, so that the tar and methane in the tar-containing mixed gas E entering the downward bed reactor 3 are fully cracked, while the yield of syngas (CO+H2) is not lost.

[0034] In the first embodiment of this disclosure, the following continues... Figure 1 As shown, the method for preparing syngas by staged gasification of biomass disclosed herein further includes: feeding solid particles D of the first particle size and semi-coke particles J into a second fluidized bed reactor 2, respectively, and reacting them with a second gasifying agent B2 introduced into the second fluidized bed reactor 2 to produce bottom slag I and a tar-free gas-solid mixture F; the tar-free gas-solid mixture F is separated by a second gas-solid separator 5 to obtain solid particles H of the second particle size and tar-free syngas G.

[0035] In the first embodiment of this disclosure, semi-coke particles J generated by pyrolysis or partial gasification in the first fluidized bed reactor 1, and solid particles D of the first size separated by the first gas-solid separator 4 are respectively transported to the second fluidized bed reactor 2 to undergo gasification reaction with the second gasifying agent B2 introduced into the second fluidized bed reactor 2, so as to further gasify the tar and methane contained in the semi-coke particles J and the solid particles D of the first size, and at the same time further convert the carbon in the semi-coke particles J and the solid particles D of the first size, thereby improving the utilization rate and carbon conversion rate of the semi-coke particles J and the solid particles D of the first size, and generating a tar-free gas-solid mixture F and bottom slag I.

[0036] Furthermore, by using an external return pipeline, the second-sized solid particles H separated by the second gas-solid separator 5 are returned to the second fluidized bed reactor 2 for secondary reaction, which can further improve the quality of syngas and carbon conversion efficiency.

[0037] In the first embodiment of this disclosure, the following continues... Figure 1 As shown, a second gasifying agent B2 is introduced into the dense phase zone of the second fluidized bed reactor 2 so that the semi-coke particles J and / or the first-size solid particles D react with the second gasifying agent B2 to produce bottom ash I and a tar-free gas-solid mixture F. Further, the second gasifying agent B2 is optionally introduced into the dilute phase zone of the second fluidized bed reactor 2 to improve the carbon conversion efficiency of the first-size solid particles D and / or the second-size solid particles H within the second fluidized bed reactor 2, wherein the particle size (d) of the first-size solid particles D is... 50 The particle size of the second-largest solid particle, H, is 60-80 μm. 50The micrometer diameter (30-40 μm) is the ash content. The second gasifying agent B2 is a mixture of oxygen and water vapor or carbon dioxide, with a molar ratio of 0.3-0.5. The degree of reaction and reaction temperature in the second fluidized bed reactor 2 are controlled by adjusting the molar ratio of oxygen to water vapor or carbon dioxide in the second gasifying agent B2. If the molar ratio of oxygen to water vapor or carbon dioxide in the second gasifying agent B2 is too low, the quality of the syngas produced by the gasification reaction in the second fluidized bed reactor 2 will be reduced; if the molar ratio of oxygen to water vapor or carbon dioxide is too high, it is easy for semi-coke particles J to slag in the second fluidized bed reactor 2, affecting the operational stability of the second fluidized bed reactor 2. The reaction temperature of the second fluidized bed reactor 2 is determined comprehensively based on the ash melting point and ash composition of biomass fuel A. Under the premise of preventing slag formation, the operating temperature in the second fluidized bed reactor 2 is as high as possible. A higher operating temperature is beneficial for improving carbon conversion efficiency, reducing the tar and methane content in the syngas, and improving the quality of the syngas. Therefore, the reaction temperature in the second fluidized bed reactor 2 of this disclosure is set to 650-900°C.

[0038] Figure 2 This is a schematic diagram of the process for preparing syngas from biomass through staged gasification in the second embodiment of this disclosure.

[0039] like Figure 2 As shown, in the second embodiment, the method for preparing syngas by biomass decomposition and gasification includes: introducing biomass fuel A and a first gasifying agent B1 or carrier gas B0 into a first fluidized bed reactor 1, extracting volatiles from biomass fuel A through pyrolysis or partial gasification reaction to produce a tar-containing gas-solid mixture C and semi-coke particles J; separating the tar-containing gas-solid mixture C through a first gas-solid separator 4 to obtain a tar-containing mixed gas E and solid particles of a first particle size D; conveying the tar-containing mixed gas E and a third gasifying agent B3 into a downward-flowing bed reactor 3, thermally cracking the tar in the tar-containing mixed gas E to produce tar-free syngas G.

[0040] In the second embodiment of this disclosure, the method for preparing syngas further includes: feeding solid particles D of the first particle size and semi-coke particles J into a second fluidized bed reactor 2, respectively, and reacting them with a second gasifying agent B2 introduced into the second fluidized bed reactor 2 to produce bottom slag I and a tar-free gas-solid mixture F; the tar-free gas-solid mixture F is separated by a second gas-solid separator 5 to obtain solid particles H of the second particle size and tar-free syngas G.

[0041] The second embodiment differs from the first embodiment in that the second-size solid particulate matter H is transported to the downflow bed reactor 3 for a secondary reaction to completely convert the carbon in the second-size solid particulate matter H, producing ash residue K and tar-free syngas G. Specifically, the second-size solid particulate matter H is directly transported to the downflow bed reactor 3 through a pipeline, where it undergoes a gasification reaction with the third gasifying agent B3 introduced into the downflow bed reactor 3. This completely converts the carbon in the second-size solid particulate matter H into ash residue K and tar-free syngas G, achieving complete conversion of biomass fuel A. Simultaneously, the heat released during the gasification reaction promotes the complete thermal cracking of tar and methane in the tar-containing mixed gas E entering the downflow bed reactor 3, improving the quality of the syngas. The reaction parameters and conditions in the second embodiment—the first gasifying agent B1 or carrier gas B0, the second gasifying agent B2, the third gasifying agent B3, the first fluidized bed reactor 1, the second fluidized bed reactor 2, and the downflow bed reactor 3—are the same as those in the first embodiment and their functions will not be described in detail here.

[0042] In the second embodiment of this disclosure, the gasification process of biomass fuel A is controlled in stages by combining a two-stage fluidized bed reactor and a downflow bed reactor. Utilizing the advantages of the fluidized bed reactor, the adaptability of biomass fuel is effectively broadened, and the tar content in the syngas is reduced. Simultaneously, the high-temperature gasification advantage of the downflow bed reactor 3 enables the complete cracking of tar and methane and the efficient and complete conversion of biomass fuel A. By adjusting the operating parameters of the fluidized bed reactor and the downflow bed reactor 3, and controlling the gasification fraction of biomass fuel A in each reactor, the composition of the syngas is regulated to meet the gas composition requirements of syngas for different chemicals. Furthermore, the staged gasification of biomass fuel A reduces the tar content in the syngas, lowers the cost of separating methane and other gases from the syngas, and improves the carbon conversion efficiency of biomass fuel A. It also prevents slagging in the furnace and tar blockage in pipelines, ensuring the long-term stability of the syngas preparation unit.

[0043] Figure 3 This is a schematic diagram of a downflow bed reactor used in the staged gasification of biomass to prepare syngas in the third embodiment of this disclosure.

[0044] like Figure 3As shown, the method for preparing syngas in the third embodiment of this disclosure is the same as that in the second embodiment, except that: the second-sized solid particles H are transported to the downflow bed reactor 3 for a secondary reaction, including: transporting the second-sized solid particles H to the gas-solid burner unit 3d, mixing them with a portion of the tar-containing mixed gas E introduced into the gas-solid burner unit 3d in a jet manner to form a jet gas-solid mixture, and using the tar-containing mixed gas E to carry the second-sized solid particles H into the downflow bed reactor 3; the third gasifying agent B3 introduced into the downflow bed reactor 3 through the gasifying agent nozzle 3b reacts with the jet gas-solid mixture, and the heat released causes another portion of the tar-containing mixed gas E introduced into the downflow bed reactor 3 through the cracked gas channel 3a to undergo a thermal cracking reaction, and the tar in the tar-containing mixed gas E is fully thermally cracked to form tar-free syngas G. The mass ratio of the tar-containing mixed gas E and the second-sized solid particles H in the jet gas-solid mixture is 1:20 to 1:30 kg / kg, the jet velocity of the jet gas-solid mixture is 20 to 50 m / s, and the portion of the tar-containing mixed gas E introduced into the gas-solid burner unit 3d accounts for 1 / 3 to 1 / 5 of the total volume of the tar-containing mixed gas E.

[0045] In the third embodiment of this disclosure, a tar-containing mixed gas E enters the downflow bed reactor 3 from two different locations for thermal cracking. A portion of the tar-containing mixed gas E enters the gas-solid burner unit 3d in a jet manner and mixes with the second-diameter solid particles H to form a jet gas-solid mixture. The tar-containing mixed gas E serves as the blowing gas for the second-diameter solid particles H, transporting them into the downflow bed reactor 3. Simultaneously, around the gas-solid burner unit 3d, a third gasifying agent B3, which is also introduced into the downflow bed reactor 3 in a jet manner, undergoes a gasification reaction to form a localized high-temperature region, maximizing the complete conversion of carbon in the second-diameter solid particles H into ash K. At the same time, the heat released during the gasification reaction of the third gasifying agent B3 and the second-diameter solid particles H provides a high-temperature cracking environment (900-1400°C) for the cracking of tar in the other portion of the tar-containing mixed gas E, which is introduced into the downflow bed reactor 3 via the cracked gas channel 3a. This allows the tar and methane in the tar-containing mixed gas E to undergo thermal cracking, forming tar-free syngas G.

[0046] As a first embodiment of the second aspect of this disclosure, an apparatus for preparing syngas through biomass decomposition and gasification is provided, combined with Figure 1 The device includes a first fluidized bed reactor 1, a first gas-solid separator 4, and a downflow bed reactor 3 connected in sequence.

[0047] The first fluidized bed reactor 1 is provided with a biomass fuel inlet 1a, an inlet 1b for the first gasifying agent B1 or carrier gas B0, an outlet 1c for discharging the first gasification product containing tar gas-solid mixture C, and a semi-coke outlet 1d for discharging semi-coke particles J.

[0048] The first gas-solid separator 4 is provided with a first gas-solid mixture inlet connected to the first gasification product outlet 1c, and a first gas outlet and a first solid outlet for discharging the tar-containing mixed gas E and the first particle size solid particles D obtained after gas-solid separation, respectively.

[0049] The downflow bed reactor 3 is provided with a downflow bed reactor gas inlet 3a1 connected to the first gas outlet of the first gas-solid separator 4, a third gasifying agent inlet 3b1, and a syngas outlet 3c for discharging tar from the tar-containing mixed gas E through thermal cracking reaction to produce tar-free syngas G.

[0050] In the first embodiment of this disclosure, biomass fuel A enters the first fluidized bed reactor 1 through biomass fuel inlet 1a, and the first gasifying agent B1 or carrier gas B0 enters the first fluidized bed reactor 1 through inlet 1b of the first gasifying agent B1 or carrier gas B0 for pyrolysis or partial gasification. The resulting tar-containing gas-solid mixture C is discharged through the first gasification product outlet 1c, and the semi-coke particles J are discharged through the semi-coke outlet 1d. The first gasification product outlet 1c is connected to the first gas-solid mixture inlet of the first gas-solid separator 4 so that the tar-containing gas-solid mixture C enters the first gas-solid separator 4 for gas-solid separation. The first-size solid particles D generated after separation are discharged through the first solid outlet, and the generated tar-containing mixed gas E is discharged through the first gas outlet. Furthermore, the first gas outlet of the first gas-solid separator 4 is connected to the gas inlet 3a1 of the downflow bed reactor 3 through a pipeline, so that the tar-containing mixed gas E can be transported into the downflow bed reactor 3 through the pipeline and undergo a thermal cracking reaction with the third gasifying agent B3 that enters the downflow bed reactor 3 through the third gasifying agent inlet 3b1, so that the tar in the tar-containing mixed gas E can be fully cracked to produce tar-free syngas G, which is discharged through the syngas outlet 3c.

[0051] Continue as Figure 1 As shown, the apparatus for preparing syngas by biomass staged gasification in the first embodiment of this disclosure further includes: a second fluidized bed reactor 2 and a second gas-solid separator 5.

[0052] The first solid outlet of the first gas-solid separator 4 is connected to the first solid particulate inlet 2a of the second fluidized bed reactor 2. The semi-coke outlet 1d of the first fluidized bed reactor 1 is connected to the second solid particulate inlet 2e of the second fluidized bed reactor 2. A second gasifying agent inlet 2b is provided in the dense phase zone of the second fluidized bed reactor 2. The second fluidized bed reactor 2 is also provided with a bottom ash outlet 2d and a second gasification product outlet 2c for discharging the bottom ash I and the tar-free gas-solid mixture F produced by the gasification reaction in the second fluidized bed reactor 2, respectively. The second gasification product outlet 2c of the second fluidized bed reactor 2 is connected to the second gas-solid mixture inlet of the second gas-solid separator 5. The second gas-solid separator 5 is also provided with a second solid outlet and a second gas outlet for discharging the second-size solid particulate matter H and the tar-free syngas G obtained by gas-solid separation, respectively. There can be one or more first solid particulate inlets 2a, which are circumferentially distributed in the upper part of the second fluidized bed reactor 2. At least one first solid particulate inlet 2a is connected to the first solid outlet of the first gas-solid separator 4. Optionally, the second solid outlet of the second gas-solid separator 5 is connected to at least one first solid particle inlet 2a. Specifically, the second solid outlet of the second gas-solid separator 5 is connected to at least one first solid particle inlet 2a via a return pipeline to return the second-diameter solid particles H to the second fluidized bed reactor 2 for secondary reaction. It should be noted that the first solid particle inlets 2a connected to the first solid outlet of the first gas-solid separator 4 and the second solid outlet of the second gas-solid separator 5 can be the same or different. "Optional" means that the second solid outlet of the second gas-solid separator 5 may or may not be connected to the first solid particle inlet 2a.

[0053] In the first embodiment of this disclosure, the coupling and matching between the reactors in the first fluidized bed reactor 1, the second fluidized bed reactor 2, the downflow bed reactor 3, the first gas-solid separator 4, and the second gas-solid separator 5 is the foundation for the stable and efficient operation of the system, with material conveying between the reactors being crucial. Depending on the particle size of the products after the reaction of biomass fuel A, the semi-coke particles J produced by the first fluidized bed reactor 1 can be conveyed into the second fluidized bed reactor 2 using either hot or cold conveying. For example, if the semi-coke particles J are small, they are directly conveyed hot to the second fluidized bed reactor 2 using pneumatic conveying; if the semi-coke particles J are large, they need to be cooled first, and then mechanically conveyed to the second fluidized bed reactor 2. The first-size solid particles D produced after separation by the first gas-solid separator 4 enter the second fluidized bed reactor 2 by natural descent. To facilitate the smooth conveying of the first-size solid particles D, blowing gas can be installed on the conveying pipeline. To improve the carbon conversion rate in the second fluidized bed reactor 2, the first solid particle inlet 2a and the second solid particle inlet 2e should be located as far as possible in the lower part of the second fluidized bed reactor 2. However, considering both the operational stability of the second fluidized bed reactor 2 and the smooth return of materials, the first solid particle inlet 2a and the second solid particle inlet 2e should not be located in the dense phase zone of the second fluidized bed reactor 2. Therefore, considering both stable material return and improved carbon conversion rate, this disclosure suggests that the first solid particle inlet 2a and the second solid particle inlet 2e should preferably be located between the dense phase zone and the dilute phase zone. Specifically, depending on the height (h) of the second fluidized bed reactor 2, the second solid particle inlet 2e and the first solid particle inlet 2a are located at a distance of 0.1h to 0.3h from the bottom of the second fluidized bed reactor 2, where h is the height of the second fluidized bed reactor 2.

[0054] According to the first embodiment of this disclosure, continuing as follows Figure 1 As shown, in order to improve the carbon conversion rate of the second fluidized bed reactor 2, one or more gasifying agent nozzles 2f are optionally provided in the dilute phase zone of the second fluidized bed reactor 2 to introduce a second gasifying agent B2 into the dilute phase zone of the second fluidized bed reactor 2 through the gasifying agent nozzles 2f, so that the first particle size solid particles D and / or the second particle size solid particles H can react with the second gasifying agent B2 in a gasification reaction. The multiple gasifying agent nozzles 2f are arranged at different heights of the second fluidized bed reactor 2.

[0055] In the second embodiment of this disclosure, by providing one or more gasifying agent nozzles 2f in the dilute phase zone (i.e., the upper part of the second fluidized bed reactor 2), the second gasifying agent B2 is introduced into the second fluidized bed reactor 2 through dispersion, thereby increasing the temperature of the dilute phase zone of the second fluidized bed reactor 2. This ensures that the first-size solid particles D and / or the second-size solid particles H are completely converted in the dilute phase zone, thereby improving the carbon conversion rate of the second fluidized bed reactor 2. To make the temperature in the dilute phase zone more uniform, multiple gasifying agent nozzles 2f can be provided at different heights along the second fluidized bed reactor 2, ensuring that the second gasifying agent B2 is in full contact with the first-size solid particles D and / or the second-size solid particles H.

[0056] According to a second embodiment of this disclosure, such as Figure 2 As shown, the apparatus for biomass decomposition and gasification to produce syngas has the same characteristics as... Figure 1 The same first fluidized bed reactor 1, first gas-solid separator 4, second fluidized bed reactor 2, second gas-solid separator 5, and downflow bed reactor 3, and their corresponding connections. Figure 2 The device shown is Figure 1 The difference in the illustrated device lies in that: the second solid outlet of the second gas-solid separator 5 is connected to the descending bed reactor 3 to transport the second-sized solid particles H into the descending bed reactor 3 for secondary reaction, and the descending bed reactor 3 is also provided with an ash outlet 3e for discharging the ash K produced by the reaction of the second-sized solid particles H. Specifically, connecting the second solid outlet of the second gas-solid separator 5 to the descending bed reactor 3 includes: connecting the second solid outlet of the second gas-solid separator 5 to the material inlet 3f of the descending bed reactor 3 through a pipeline, so that the second-sized solid particles H are directly transported into the descending bed reactor 3 to be fed with the third gasifying agent B3 for secondary reaction to produce tar-free syngas G and ash K. It should be noted that: Figure 2 The apparatus shown does not have one or more gasifying agent nozzles 2f in the dilute phase zone of the second fluidized bed reactor 2, but this does not mean that gasifying agent nozzles 2f cannot be provided in the dilute phase zone of the second fluidized bed reactor 2. (This is from the second embodiment of the present disclosure.) Figure 2 This is merely an example to illustrate that the gasifying agent nozzle 2f may not be provided in the dilute phase zone of the second fluidized bed reactor 2.

[0057] In the second embodiment of this disclosure, the second solid outlet of the second gas-solid separator 5 is directly connected to the material inlet 3f of the downflow bed reactor 3 via a pipeline, so as to transport the second-sized solid particles H into the downflow bed reactor 3 and react with the third gasifying agent B3 introduced into the downflow bed reactor 3 via the pipeline to completely convert the second-sized solid particles H into ash slag K. The heat released during the gasification reaction provides a high-temperature environment for the thermal cracking reaction of the tar-containing mixed gas E, which helps to fully crack the tar and methane in the tar-containing mixed gas E to form tar-free syngas G. At the same time, the biomass fuel A achieves complete carbon conversion through staged gasification of the first fluidized bed reactor 1, the second fluidized bed reactor 2 and the downflow bed reactor 3, thereby improving the carbon conversion efficiency.

[0058] According to a third embodiment of this disclosure, the apparatus for preparing syngas by biomass decomposition and gasification has the same characteristics as... Figure 1 and Figure 2 The same first fluidized bed reactor 1, first gas-solid separator 4, second fluidized bed reactor 2, second gas-solid separator 5, and downflow bed reactor 3, and their corresponding connections. Figure 3 The apparatus for preparing syngas shown is Figure 1 The difference in the apparatus shown is that the second solid outlet of the second gas-solid separator 5 is connected to the downward-flowing bed reactor 3; and Figure 2The difference in the device shown is that the second solid outlet of the second gas-solid separator 5 is connected to the material inlet 3f of the descending bed reactor 3 through the gas-solid burner unit 3d. Multiple gasifying agent nozzles 3b and multiple cracked gas channels 3a are provided on the descending bed reactor 3. The gas-solid burner unit 3d is located on the central axis of the descending bed reactor 3. Multiple gasifying agent nozzles 3b are arranged symmetrically around the gas-solid burner unit 3d. Multiple cracked gas channels 3a are arranged symmetrically around the gasifying agent nozzles 3b. The angle β between the gasifying agent nozzles 3b and the cracked gas channels 3a and the central axis of the descending bed reactor 3 is 135°-175°. Furthermore, the gas-solid burner unit 3d is provided with a first channel 3d1 connected to the second solid outlet of the second gas-solid separator 5 and multiple second channels 3d2 inclinedly connected to the first channel 3d1. The first channel 3d1 is used to transport solid particles H of the second particle size, and the second channels 3d2 are used to transport part of the tar-containing mixed gas E. The solid particles H of the second particle size and the tar-containing mixed gas E are mixed in the gas-solid burner unit 3d to form a jet gas-solid mixture. The jet gas-solid mixture enters the downward bed reactor 3 through the material inlet 3f of the downward bed reactor 3. The angle α between the second channel 3d2 and the first channel 3d1 is 5°-30°. The gasifying agent nozzle 3b has a gasifying agent channel, which is connected to the third gasifying agent inlet 3b1. The gasifying agent channel is configured to transport the third gasifying agent B3 to the downward bed reactor 3. The cracked gas channel 3a is connected to the gas inlet 3a1 of the downward bed reactor 3 to introduce another part of the tar-containing mixed gas E into the downward bed reactor 3.

[0059] In the third embodiment of this disclosure, a tar-containing mixed gas E enters the descending bed reactor 3 from two different locations. A portion of the tar-containing mixed gas E is introduced into the second channel 3d2 of the gas-solid burner unit 3d in the form of a jet, and mixes with the second-size solid particles H introduced into the first channel 3d1 of the gas-solid burner unit 3d to form a high-speed jet gas-solid mixture. This portion of the tar-containing mixed gas E is used as a blowing gas to transport the second-size solid particles H into the descending bed reactor 3. The jet velocity of the formed high-speed jet gas-solid mixture is 20 to 50 m / s, and the mass ratio of the portion of the tar-containing mixed gas E to the second-size solid particles H is 1:20 to 1:30 kg / kg. The formed jet gas-solid mixture is injected into the descending bed reactor 3 in a dense phase transport manner. From the perspective of material conveying, the angle α between the tar-containing mixed gas E and the second-diameter solid particles H in the conveying section is 5°-30°, that is, the angle α between the second channel 3d2 and the first channel 3d1 is 5°-30°.

[0060] Another portion of the tar-containing mixed gas E is introduced into the downward-flowing bed reactor 3 through the cracking gas channel 3a for cracking reaction. The tar-containing mixed gas E used as blowing gas accounts for 1 / 3 to 1 / 5 of the total volume of the tar-containing mixed gas E. To maximize the conversion of carbon in the second-diameter solid particles H within the downward-flowing bed reactor 3, while minimizing the consumption of effective gas (CO+H2) in the tar-containing mixed gas E, the structure and angle of the cracking gas channel 3a through which the third gasifying agent B3 is introduced, as well as the gas-solid burner unit 3d through which the second-diameter solid particles H are introduced, are optimized. This optimization aims to ensure that the heat required for the thermal cracking reaction of the tar-containing mixed gas E in the downward-flowing bed reactor 3 is provided as much as possible by burning the carbon in the second-diameter solid particles H, thereby reducing the consumption of effective gas (CO+H2) in the tar-containing mixed gas E. Therefore, multiple gasifying agent nozzles 3b are arranged around the gas-solid burner unit 3d. These nozzles are symmetrically positioned near the material inlet 3f of the descending bed reactor 3, allowing the third gasifying agent B3, introduced in a high-speed jet, to react with the second-diameter solid particles H in the jet gas-solid mixture, forming a localized high-temperature zone (900-1400℃) and achieving efficient conversion of the second-diameter solid particles H. Multiple pyrolysis gas channels 3a are symmetrically arranged around the gasifying agent nozzles 3b. The high-temperature zone formed by the gasification reaction promotes the thermal cracking of tar and methane in another portion of the tar-containing mixed gas E entering the descending bed reactor 3 via the pyrolysis gas channels 3a, forming tar-free syngas G. Considering the effective contact between the third gasifying agent B3 and the jet gas-solid mixture, as well as the other portion of the tar-containing mixed gas E, the angle β between the gasifying agent nozzles 3b and the pyrolysis gas channels 3a and the central axis of the descending bed reactor 3 is 135°-175°.

[0061] In the first to third embodiments of this disclosure, the first fluidized bed reactor 1 and the second fluidized bed reactor 2 are either bubbling fluidized bed reactors or circulating fluidized bed reactors.

[0062] In summary, the primary function of the first fluidized bed reactor 1 in this embodiment is to extract volatiles from biomass fuel, producing a gas-solid mixture with high tar and methane content (i.e., tar-containing gas-solid mixture C) and semi-coke particles J. The primary function of the second fluidized bed reactor 2 is to gasify the semi-coke particles J produced in the first fluidized bed reactor 1, generating tar-free syngas G. The primary function of the downflow bed reactor 3 is to crack the tar-containing gas-solid mixture C produced in the first fluidized bed reactor 1 to generate tar-free syngas G, and to further convert the residual carbon in the semi-coke particles J, improving the carbon conversion rate. By combining the fluidized bed reactor and the downflow bed reactor, staged control of the biomass gasification process is achieved. While utilizing the advantages of the fluidized bed reactor to broaden the adaptability of biomass fuel and reduce the tar content in the syngas, the high-temperature gasification advantage of the downflow bed reactor enables the thermal cracking of tar and methane and the efficient conversion of biomass. By adjusting the operating parameters of fluidized bed reactors and downward flow bed reactors and controlling the gasification ratio of biomass in each reactor, the composition of syngas can be precisely controlled to meet the gas composition requirements for the synthesis of different chemicals.

[0063] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for preparing syngas from biomass through staged gasification, characterized in that, The method includes: Biomass fuel (A) and a first gasifying agent (B1) or carrier gas (B0) are introduced into a first fluidized bed reactor (1) and the volatiles in the biomass fuel (A) are extracted through pyrolysis or partial gasification to produce a tar-containing gas-solid mixture (C) and semi-coke particles (J). The tar-containing gas-solid mixture (C) is separated by the first gas-solid separator (4) to obtain tar-containing mixed gas (E) and solid particles of the first particle size (D); The tar-containing mixed gas (E) and the third gasifying agent (B3) are transported to the downflow bed reactor (3), where the tar in the tar-containing mixed gas (E) is thermally decomposed through a thermal cracking reaction to produce tar-free syngas (G).

2. The method according to claim 1, characterized in that, The method further includes: The first-size solid particles (D) and the semi-coke particles (J) are respectively fed into the second fluidized bed reactor (2) and reacted with the second gasifying agent (B2) introduced into the second fluidized bed reactor (2) to produce bottom ash (I) and tar-free gas-solid mixture (F); The tar-free gas-solid mixture (F) is separated by the second gas-solid separator (5) to obtain solid particles (H) of the second particle size and tar-free syngas (G).

3. The method according to claim 2, characterized in that, The second-sized solid particles (H) are returned to the second fluidized bed reactor (2) via the return pipeline for secondary reaction; or The second-sized solid particles (H) are fed into a downflow bed reactor (3) for a secondary reaction to completely convert the carbon in the second-sized solid particles (H) to produce ash (K) and tar-free syngas (G).

4. The method according to claim 3, characterized in that, The second-sized solid particles (H) are fed into the descending bed reactor (3) for a secondary reaction, including: The second-sized solid particles (H) are directly transported through a pipeline into the downward-flowing bed reactor (3) for secondary reaction; or The second-size solid particles (H) are transported into the gas-solid burner unit (3d) and mixed with a portion of the tar-containing mixed gas (E) introduced into the gas-solid burner unit (3d) in a jet manner to form a jet gas-solid mixture. The second-size solid particles (H) are carried into the downflow bed reactor (3) by the tar-containing mixed gas (E). The third gasifying agent (B3) introduced into the downflow bed reactor (3) through the gasifying agent nozzle (3b) reacts with the jet gas-solid mixture, and the heat released causes another part of the tar-containing mixed gas (E) introduced into the downflow bed reactor (3) through the cracking gas channel (3a) to undergo a thermal cracking reaction to form tar-free syngas (G).

5. The method according to claim 4, characterized in that, The mass ratio of the tar-containing mixed gas (E) and the second-sized solid particles (H) in the jet gas-solid mixture is 1:20 to 1:30 kg / kg, the jet velocity of the jet gas-solid mixture is 20 to 50 m / s, and the portion of the tar-containing mixed gas (E) introduced into the gas-solid burner unit (3d) accounts for 1 / 3 to 1 / 5 of the total volume of the tar-containing mixed gas (E).

6. The method according to claim 1, characterized in that, When a partial gasification reaction occurs in the first fluidized bed reactor (1), a first gasifying agent (B1) is introduced into the first fluidized bed reactor (1). The first gasifying agent (B1) is a mixture of oxygen and water vapor or carbon dioxide. When a pyrolysis reaction occurs in the first fluidized bed reactor (1), a carrier gas (B0) is introduced into the first fluidized bed reactor (1), wherein the carrier gas (B0) includes either nitrogen or carbon dioxide.

7. The method according to claim 6, characterized in that, In the first gasifying agent (B1), the molar ratio of oxygen to water vapor or carbon dioxide is 0.3-0.5, and the reaction temperature in the first fluidized bed reactor (1) is 450-650℃.

8. The method according to claim 1 or 4, characterized in that, The third gasifying agent (B3) is selected from oxygen or a mixture of oxygen and water vapor, wherein the molar ratio of oxygen to water vapor is 0.6-0.9, and the reaction temperature in the downward bed reactor (3) is 900-1400℃.

9. The method according to claim 3, characterized in that, A second gasifying agent (B2) is introduced into the dense phase zone of the second fluidized bed reactor (2) so that the semi-coke particles (J) and / or the first-size solid particles (D) react with the second gasifying agent (B2) in a gasification reaction. The second gasifying agent (B2) is a mixture of oxygen and water vapor or carbon dioxide. Optionally, the second gasifying agent (B2) is introduced into the dilute phase region of the second fluidized bed reactor (2) to improve the carbon conversion efficiency of the first-size solid particles (D) and / or the second-size solid particles (H) in the second fluidized bed reactor (2).

10. The method according to claim 9, characterized in that, In the second gasifying agent (B2), the molar ratio of oxygen to water vapor or carbon dioxide is 0.3-0.5, and the reaction temperature in the second fluidized bed reactor (2) is 650-900℃.

11. An apparatus for producing syngas from biomass through staged gasification, characterized in that, The device includes: a first fluidized bed reactor (1), a first gas-solid separator (4), and a downflow bed reactor (3) connected in sequence; The first fluidized bed reactor (1) is provided with a biomass fuel inlet (1a), an inlet (1b) for a first gasifying agent (B1) or carrier gas (B0), a first gasification product outlet (1c) for discharging a tar-containing gas-solid mixture (C), and a semi-coke outlet (1d) for discharging semi-coke particles (J). The first gas-solid separator (4) is provided with a first gas-solid mixture inlet connected to the first gasification product outlet (1c), and a first gas outlet and a first solid outlet for discharging the tar-containing mixed gas (E) and the first-size solid particles (D) obtained after gas-solid separation, respectively; and The downflow bed reactor (3) is provided with a downflow bed reactor gas inlet (3a1) connected to the first gas outlet of the first gas-solid separator (4), a third gasifying agent inlet (3b1), and a syngas outlet (3c) for discharging the tar-containing mixed gas (E) to produce tar-free syngas (G) through thermal cracking reaction.

12. The apparatus according to claim 11, characterized in that, The device also includes: a second fluidized bed reactor (2) and a second gas-solid separator (5); The first solid outlet of the first gas-solid separator (4) is connected to the first solid particulate inlet (2a) of the second fluidized bed reactor (2), the semi-coke outlet (1d) of the first fluidized bed reactor (1) is connected to the second solid particulate inlet (2e) of the second fluidized bed reactor (2), a second gasifying agent inlet (2b) is provided in the dense phase zone of the second fluidized bed reactor (2), and the second fluidized bed reactor (2) is also provided with a bottom ash outlet (2d) and a second gasification product outlet (2c) for discharging the bottom ash (I) and the tar-free gas-solid mixture (F) generated by the gasification reaction in the second fluidized bed reactor (2), respectively; and The second gasification product outlet (2c) of the second fluidized bed reactor (2) is connected to the second gas-solid mixture inlet of the second gas-solid separator (5). The second gas-solid separator (5) is also provided with a second solid outlet and a second gas outlet for discharging solid particles (H) of the second particle size obtained by gas-solid separation and tar-free syngas (G). There are one or more first solid particulate inlets (2a), and multiple first solid particulate inlets (2a) are circumferentially distributed on the upper part of the second fluidized bed reactor (2). At least one first solid particulate inlet (2a) is connected to the first solid outlet of the first gas-solid separator (4), and optionally the second solid outlet of the second gas-solid separator (5) is connected to at least one first solid particulate inlet (2a).

13. The apparatus according to claim 12, characterized in that, The second solid outlet of the second gas-solid separator (5) is connected to at least one of the first solid particle inlets (2a) via a return pipeline to return the second-sized solid particles (H) to the second fluidized bed reactor (2) for secondary reaction; or The second solid outlet of the second gas-solid separator (5) is connected to the downflow bed reactor (3) to transport the second particle size solid particles (H) into the downflow bed reactor (3) for secondary reaction, and the downflow bed reactor (3) is also provided with an ash outlet (3e) for discharging the ash slag (K) generated by the reaction of the second particle size solid particles (H).

14. The apparatus according to claim 13, characterized in that, The second solid particulate inlet (2e) and the first solid particulate inlet (2a) are located at a distance of 0.1h to 0.3h from the bottom of the second fluidized bed reactor (2), where h is the height of the second fluidized bed reactor (2). Optionally, one or more gasifying agent nozzles (2f) are provided in the dilute phase zone of the second fluidized bed reactor (2) to introduce a second gasifying agent (B2) into the dilute phase zone of the second fluidized bed reactor (2) through the gasifying agent nozzles (2f) so that the first particle size solid particles (D) and / or the second particle size solid particles (H) react with the second gasifying agent (B2) in a gasification reaction, wherein the plurality of gasifying agent nozzles (2f) are provided at different heights of the second fluidized bed reactor (2).

15. The apparatus according to claim 13, characterized in that, Connecting the second solid outlet of the second gas-solid separator (5) to the downward-flowing bed reactor (3) includes: The second solid outlet of the second gas-solid separator (5) is connected to the material inlet (3f) of the downflow bed reactor (3) via a pipeline; or The second solid outlet of the second gas-solid separator (5) is connected to the material inlet (3f) of the downflow bed reactor (3) through a gas-solid burner unit (3d). Multiple gasifying agent nozzles (3b) and multiple cracked gas channels (3a) are provided on the downflow bed reactor (3). The gas-solid burner unit (3d) is located on the central axis of the downflow bed reactor (3). Multiple gasifying agent nozzles (3b) are arranged symmetrically around the gas-solid burner unit (3d). Multiple cracked gas channels (3a) are arranged symmetrically around the gasifying agent nozzles (3b). The included angle β between the gasifying agent nozzles (3b) and the cracked gas channels (3a) and the central axis of the downflow bed reactor (3) is 135°-175°. The gas-solid burner unit (3d) is provided with a first channel (3d1) connected to the second solid outlet of the second gas-solid separator (5) and a plurality of second channels (3d2) inclinedly arranged through the first channel (3d1). The first channel (3d1) is used to transport the second-size solid particles (H), and the second channels (3d2) are used to transport the tar-containing mixed gas (E). The second-size solid particles (H) and the tar-containing mixed gas (E) are mixed in the gas-solid burner unit (3d) to form a jet gas-solid mixture. The jet gas-solid mixture enters the downward bed reactor (3) through the material inlet (3f) of the downward bed reactor. The angle α between the second channel (3d2) and the first channel (3d1) is 5°-30°.

16. The apparatus according to claim 15, characterized in that, The tar-containing mixed gas (E) is transported through a pipeline into the downward-flowing bed reactor (3); or The gasifying agent nozzle (3b) has a gasifying agent channel connected to the third gasifying agent inlet (3b1), which is configured to deliver the third gasifying agent (B3) to the downflow bed reactor (3); the cracked gas channel (3a) is connected to the downflow bed reactor gas inlet (3a1) to introduce the tar-containing mixed gas (E) into the downflow bed reactor (3).

17. The apparatus according to claim 12, characterized in that, The first fluidized bed reactor (1) and the second fluidized bed reactor (2) are either bubbling fluidized bed reactors or circulating fluidized bed reactors.

Images