Biomass pressurized gasification system

Abstract

The utility model provides a kind of biomass pressurized gasification system, comprising: biomass is added to reactor;The gas required for biomass gasification reaction and fluidization gas, after entering reactor by admission unit control;High-temperature ash from reactor is sent to atmospheric equipment after being cooled by deslagging unit;In waste heat recovery unit, synthesis gas is heat-exchanged by three stages;Synthesis gas from waste heat recovery unit enters dust removal unit to separate gas and particle, and after the synthesis gas after separating particle enters water washing cooling unit;The particle separated and captured in dust removal unit is sent back to reactor by fly ash return furnace unit;Synthesis gas from dust removal unit is sent to downstream device after being cooled in water washing cooling unit.The utility model provides a kind of biomass pressurized gasification system, the temperature of reactor upper section is higher than reactor lower section, tar generated in reactor lower section is further converted in reactor upper section, effectively reduces the tar content in synthesis gas of reactor outlet.

Description

[0001] This application claims priority to Chinese Patent Application No. 202411711442.7, filed on November 27, 2024, entitled "A Solid Biomass Pressurized Gasification Process", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to the field of biomass pressurized gasification technology, and more specifically, to a biomass pressurized gasification system. Background Technology

[0003] With the ever-increasing demand for energy, fossil fuels, as the primary energy source, are dwindling, leading to serious environmental problems. Therefore, seeking renewable alternatives has become the future direction of energy development. Biomass energy is an ideal renewable energy source and is the world's fourth largest energy source. Utilizing biomass energy has two major advantages: first, as a renewable energy source, it allows humanity to break free from dependence on fossil fuels; second, it is beneficial to environmental improvement, as the amount of CO2 emitted during biomass utilization is equal to the amount of CO2 absorbed during its formation. Therefore, replacing fossil fuels with biomass helps mitigate the greenhouse effect.

[0004] Among numerous biomass utilization technologies, biomass gasification is the most promising and easily scaled-up technology. Biomass gasification can generate medium- and low-calorific-value fuels that can be used for industrial fuels, chemical synthesis, or power generation, and its efficiency is higher compared to other technologies. Currently, fixed-bed gasification technology is simple to manufacture and operate, but its scale is small, and the gasification process produces difficult-to-handle tar, limiting its development and application. Fluidized-bed gasification technology, due to its wide adaptability to feedstocks, good gas-solid heat and mass transfer performance, and uniform mixing, is one of the technologies that is easy to apply on a large scale for biomass gasification. However, the relatively low temperature of biomass fluidized-bed gasification and the production of tar are current problems with this process. Utility Model Content

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A biomass pressurized gasification system for pressurized gasification of biomass, comprising:

[0007] The feeding unit is used to add biomass to the reactor;

[0008] The air intake unit controls the entry of the gas and fluidizing gas required for the biomass gasification reaction into the reactor.

[0009] The reactor converts biomass and fly ash into syngas and ash residue;

[0010] A separator for receiving the synthesis gas exiting from the top of the reactor;

[0011] The waste heat recovery unit is used to receive the syngas after it leaves the separator, cool the syngas, and recover heat at the same time.

[0012] A slag discharge unit is used to receive the ash slag discharged from the bottom of the reactor;

[0013] The dust removal unit separates the syngas from the waste heat recovery unit into gas and particles;

[0014] The water washing and cooling unit receives the syngas after particle separation, and washes and cools the syngas with water before sending it to the downstream device.

[0015] It also includes a fly ash return unit for receiving particles separated and collected by the dust removal unit;

[0016] The gas required for the biomass gasification reaction and the fluidizing gas in the fluidizing gas are syngas, water vapor, or a mixture of syngas and water vapor.

[0017] Preferably, in the above-mentioned biomass pressurized gasification system, the biomass is fed into the feeding unit, metered, and then added to the reactor through a conveying device under the combined action of the biomass' own gravity and the kinetic energy of the conveying gas. The conveying gas for the biomass is inert gas, syngas, or a mixture of both.

[0018] Preferably, in the above-mentioned biomass pressurized gasification system, the separator is composed of one or more sets of cyclone separators connected in series, and each set of cyclone separators is a collection of one or more cyclone separators.

[0019] Preferably, in the above-mentioned biomass pressurized gasification system, the fly ash separated by the separator is returned to the reactor.

[0020] Preferably, in the above-mentioned biomass pressurized gasification system, the heat exchange in the waste heat recovery unit is in three stages. The syngas from the separator first exchanges heat with water, water vapor, or a mixture of water and water vapor and is cooled to 650°C to 750°C. Then it is mixed with a quenching medium and cooled to 450°C to 550°C. Finally, it exchanges heat with water, water vapor, or a mixture of water and water vapor and is cooled to 350°C to 400°C before leaving the waste heat recovery unit.

[0021] Preferably, in the above-mentioned biomass pressurized gasification system, the quenching medium is water, water vapor, syngas, or other gases.

[0022] Preferably, in the above-mentioned biomass pressurized gasification system, the dust removal unit includes a dust collector and a backflushing air, and the filter element of the dust collector is a metal filter or a ceramic filter.

[0023] Preferably, in the above-mentioned biomass pressurized gasification system, the backflush gas is an inert gas, a syngas, or a mixture of both.

[0024] Preferably, in the above-mentioned biomass pressurized gasification system, the fly ash separated and collected by the dust removal unit is sent back to the reactor via the fly ash return unit.

[0025] Preferably, in the above-mentioned biomass pressurized gasification system, in the fly ash return unit, the fly ash is sent back to the reactor under the action of conveying gas, which is inert gas or syngas.

[0026] Preferably, in the above-mentioned biomass pressurized gasification system, the syngas contains CO and H2-rich gas from the dust removal unit, CO and H2-rich gas after further treatment following discharge from the dust removal unit, or a mixture of the two.

[0027] Preferably, in the above-mentioned biomass pressurized gasification system, the syngas from the dust removal unit is cooled by a heat exchanger in the water washing and cooling unit and then enters the water washing tower. After heat and mass transfer with the washing water, the gas exiting the water washing and cooling unit is sent to the downstream device as product gas.

[0028] Preferably, in the above-mentioned biomass pressurized gasification system, the gas from the water washing and cooling unit is cooled to 30°C to 180°C.

[0029] Preferably, in the above-mentioned biomass pressurized gasification system, the biomass from the feed unit, the fly ash returned from the separator, the fly ash from the fly ash return unit, and the gasifying agent from the gas inlet unit are converted into syngas containing CO and H2 and ash residue in the reactor.

[0030] Preferably, in the above-mentioned biomass pressurized gasification system, the reactor is a fluidized bed gasifier, and the upper and lower sections of the reactor are provided with one or more gasifying agent inlets, and the internal pressure of the reactor is 0.1MPa-7.5MPa.

[0031] Preferably, in the above-mentioned biomass pressurized gasification system, the internal temperature of the lower section of the reactor is 750℃~850℃, the internal temperature of the upper section of the reactor is 950℃~1050℃, and the diameter of the upper section of the reactor is larger than the diameter of the lower section of the reactor.

[0032] The biomass pressurized gasification system provided by this utility model has a higher temperature in the upper section of the reactor than in the lower section. The tar generated in the lower section is further converted in the upper section, effectively reducing the tar content in the syngas at the reactor outlet. By rationally selecting the operating temperature of the syngas in the heat exchanger of the waste heat recovery unit, the corrosion and scaling of the heat exchanger by alkali metals or alkaline earth metals carried by the syngas are effectively reduced. Syngas replaces steam as the fluidizing gas in the reactor, greatly reducing the amount of steam used and the amount of wastewater discharged from the gasification process system. Compared with using CO2-rich gas from the syngas purification device, using syngas as the conveying gas for solid particles entering the reactor can save the power consumption of gas compression. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a system flow diagram of the biomass pressurized gasification system of this utility model;

[0035] Figure 2 This is a schematic diagram of the gas supply and fluidization gas sources in the biomass pressurized gasification system of this utility model;

[0036] Figure 3 This is a schematic diagram of the reactor structure used in the biomass pressurized gasification system of this utility model.

[0037] Explanation of the labels in the attached drawings:

[0038] 10-Preparation device, 20-Gasification device, 30-Conversion device, 40-First compression device, 50-Purification device, 60-Second compression device;

[0039] 210-Feeding unit, 220-Air inlet unit, 230-Reactor, 240-Separator, 250-Slag discharge unit, 260-Waste heat recovery unit, 270-Dust removal unit, 280-Fly ash return unit, 290-Water washing and cooling unit;

[0040] 01, 11 - Solid biomass, 02 - O2-rich gas, 03 - Steam, 04 - H2-rich gas, 21 - Synthesis gas, 31 - Shift gas, 41, 42, 43 - Shift gas, 51 - Purified gas, 52 - CO2-rich gas, 61 - Fresh gas;

[0041] 201, 211 - Solid biomass; 202 - O2-rich gas; 203 - Steam; 204, 207 - Conveying gas; 205 - Fluidizing gas; 206 - Backflush gas; 208 - Quenching medium; 209 - Washing water; 231, 241, 261, 271, 291 - Syngas; 221 - Gasifying agent; 232, 251 - Ash; 242, 272, 281 - Fly ash; 292 - Tar-containing water;

[0042] 2301 - Lower section of reactor, 2303 - Upper section of reactor, 2304 - Distributor, 2311, 2312, 2313, 2315 - Gasification agent inlet, 2314, 2317, 2318 - Feed inlet, 2316 - Discharge outlet. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0044] In the description of the utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of a utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In utility models, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the utility model according to the specific circumstances.

[0047] Unless otherwise expressly specified or limited, the term "synthesis gas" should be understood as a gas containing CO and H2.

[0048] The specific implementation is as follows:

[0049] like Figure 1 As shown, this utility model provides a solid biomass pressurized gasification system. The process steps implemented through a solid biomass pressurized gasification system are as follows:

[0050] The solid biomass pressurized gasification system includes a feeding unit 210, an air intake unit 220, a reactor 230, a separator 240, a slag discharge unit 250, a waste heat recovery unit 260, a dust removal unit 270, a fly ash return unit 280, and a water washing and cooling unit 290. The implementation process includes the following steps:

[0051] 1) Feeding: After being processed and qualified by the upstream preparation device, the solid biomass 201 is sent to the feeding unit 210. After being metered, it is added to the reactor 230 by the combined action of the solid biomass 201's own gravity and the kinetic energy of the conveying gas 204 through the conveying device. The solid biomass 211 can enter the reactor 230 from the feeding unit 210 through one, two, or more channels. The conveying gas 204 used to transport the solid biomass in the feeding unit 210 can be an inert gas (rich in N2 or CO2) or syngas, preferably syngas from the dust removal unit 270 and its downstream. The solid biomass 201 entering the feeding unit 210 is generally required to have an external moisture content of no more than 30% and a particle size of 5mm to 30mm.

[0052] 2) Air Inlet: The O2-rich gas 202, steam 203, and fluidizing gas 205 required for the reaction in reactor 230 are controlled and metered by the air inlet unit 220, mixed in the required proportions, and then enter reactor 230 through different channels. The gas composition in each channel can be the same or different. The O2-rich gas 202 can be essentially pure O2, obtained from the atmosphere via the air separation unit. The fluidizing gas 205 required for the fluidizing of the reactor 230 bed can be water vapor, syngas, or a mixture of both, preferably syngas from the dust removal unit 270 and its downstream. Using syngas instead of water vapor can reduce the amount of water vapor used and the wastewater discharge of the gasification process system.

[0053] 3) Gasification: Solid biomass 211 from feed unit 210, fly ash 242 from separator 240, and fly ash 281 from fly ash return unit 280, along with gasifying agent 221 (oxygen, steam, and syngas) from gasification unit 221, are converted into syngas containing CO and H2 and ash residue in reactor 230. Syngas 231, carrying a large amount of particles (fly ash), exits from the top of reactor 230 and enters separator 240. The carbon content of the particles is 20%–80%. Most of the particles are separated from syngas 231 by separator 240. Unseparated particles leave separator 240 with syngas 241 and enter waste heat recovery unit 260. The separated particles (fly ash 242) are mainly relatively large particles, accounting for 50%–99% of the total mass of particles carried by syngas 231. Fly ash 242 is returned to reactor. Ash 232 leaves from the bottom of reactor 230 and enters slag discharge unit 250.

[0054] Reactor 230 is a fluidized bed gasifier. The upper and lower sections of reactor 230 can each have one or more gasifying agent inlets. The internal pressure of reactor 230 is 0.1 MPa (gauge pressure) to 7.5 MPa (gauge pressure). The internal temperature of the lower section of reactor 230 is 750℃ to 850℃. Too low a temperature is detrimental to biomass reaction and conversion, leading to a higher carbon content in ash 232 and an increase in CH4 content in syngas 231. Too high a temperature may cause slagging of biomass ash due to its low ash melting point, thus affecting the continuous and stable operation of the system. The internal temperature of the upper section of reactor 230 is 950℃ to 1050℃. The syngas generated in the lower section of reactor 230 carries unreacted residual carbon particles, tar, and fly ash into the upper section of reactor 230 for high-temperature gasification, tar cracking, and solid particle ash removal.

[0055] The separator 240 can be configured as one or more sets of cyclone separators connected in series, and each set of cyclone separators can be a collection of one or more cyclone separators.

[0056] 4) Slag discharge: The high-temperature ash 232 from the reactor 230 is cooled and sent to the atmospheric pressure equipment through the slag discharge unit 250. The height of solid material accumulation in the reactor 230 can be controlled by adjusting the amount of ash 232 discharged from the reactor.

[0057] 5) Waste Heat Recovery: In the waste heat recovery unit 260, the syngas (and particles) 241 from the separator 240 are first cooled to 650°C–750°C by heat exchange with water, steam, or a mixture of water and steam. Then, after mixing with the quenching medium 208, the temperature is further reduced to 450°C–550°C. Finally, after heat exchange with water, steam, or a mixture of water and steam, the temperature is reduced to 350°C–400°C (greater than the tar dew point) before leaving the waste heat recovery unit 260. The waste heat recovery unit 260 may produce steam as a byproduct. The quenching medium 208 can be water, steam, syngas, or other gases. Preferably, the quenching medium 208 contains syngas rich in CO and H2 from the dust removal unit 270, or a CO and H2-rich gas discharged from the dust removal unit 270 after further treatment, or a mixture of both. Syngas (and particles) 241 rapidly decreases in temperature from 650℃~750℃ to 450℃~550℃, causing the alkali metals contained in syngas 241 to quickly transform from a gaseous state to a solid state, thereby preventing heat exchanger corrosion and scaling caused by alkali metals adhering to the metal wall. The temperature of syngas 261 when it leaves the waste heat recovery unit and enters the dust removal unit 270 is higher than the tar dew point, effectively preventing the liquid tar after condensation of gaseous tar from aggregating with the particles carried in syngas 261 and causing blockages in the flow channel of syngas 261 and the downstream dust removal unit 270.

[0058] 6) Dust Removal: Synthesis gas 261 from waste heat recovery unit 260 enters dust removal unit 270 for gas-particle separation. Synthesis gas 271 with a particle content not exceeding 2 mg / Nm3 after particle separation enters water washing and cooling unit 290. The particles (fly ash 272) separated and collected by dust removal unit 270 are sent to fly ash return unit 280. The dust removal equipment of the dust removal unit can be a dust collector or a cyclone separator downstream of a series dust collector. The filter element of the dust collector can be a metal filter element or a ceramic filter element.

[0059] 7) Fly Ash Return to Reactor: The carbon content of the particles (fly ash 272) separated and collected by the dust removal unit 270 is 20% to 80%. To improve the utilization rate of carbon in biomass 201 and reduce energy consumption, in the fly ash return to reactor 230 for further reaction and conversion under the action of conveying gas 207 in the fly ash return to reactor 280. The conveying gas 207 can be an inert gas (rich in N2 or rich in CO2), syngas, or a mixture of both, preferably syngas from the dust removal unit 270 and its downstream.

[0060] 8) Water Washing Cooling: In the water washing cooling unit 290, the syngas 271 from the dust removal unit 270 is cooled to 140℃~200℃ by a heat exchanger before entering the water washing tower. After heat and mass transfer with the washing water 209, the syngas 291 exiting the water washing tower at 30℃~180℃ is sent to downstream units as the product gas of the pressurized gasification process system. The particulate content of the syngas 291 is not higher than 0.1mg / Nm3. The gas (syngas 231) generated in the reactor 230 contains a certain amount of tar. Most of this tar is condensed into water in the water washing cooling unit 290. The tar content of the syngas 291 is not higher than 50mg / Nm3. The washing water 209, which undergoes heat and mass transfer with the syngas 271, enters the water washing tower from the top and exits the water washing tower from the bottom or bottom, carrying the condensed tar (including tar-water 292). The water washing tower is a tower-type container.

[0061] The internal pressure of the fluidized bed reactor 230 is 1.0 MPa (gauge pressure). The temperature of the lower section of the reactor 230 is 750℃~850℃, and the internal temperature of the upper section of the reactor 230 is 950℃~1050℃. The net calorific value of the solid biomass 201 is 14.65 MJ / kg. Other parameters of the solid biomass 201 are shown in the specifications in Tables 1 to 4. The composition of the syngas 231 is shown in Table 5, and the composition of the shift gases 41 / 42 / 43 is shown in Table 6.

[0062] Table 1 Solid Biomass Specifications - Industrial Analysis

[0063]

[0064] Table 2 Solid Biomass Specifications - Elemental Analysis (Dry Basis)

[0065]

[0066] Table 3 Solid Biomass Specifications - Ash Fusion Analysis

[0067]

[0068] Table 4 Solid Biomass Specifications - Ash Composition Analysis

[0069]

[0070] Table 5 Syngas Specifications

[0071]

[0072]

[0073] Table 6 Specifications of Shift Gas

[0074]

[0075]

[0076] The process of converting solid carbonaceous feedstock into syngas for methanol or ammonia production includes the following steps: gasification (forming syngas optionally containing tar fractions), tar reforming or removal (if tar is present), conditioning the syngas via water-gas shift, removal of acidic gases and impurities (H2S, COS, and partial CO2 removal), and compression. Figure 2 As shown in the example, the raw material solid biomass 01 is treated in the preparation device 10 to determine its moisture content, particle size, etc. The qualified solid biomass 11 is sent to the gasification device 20 to react with O2-rich gas 02, steam 03, etc. After the reaction, the biomass is converted into syngas and ash. The high-temperature dusty syngas, after waste heat recovery, dust removal, and water washing to separate most of the tar, enters the downstream conversion device 30 at 30℃~180℃. Under the same pressure, the higher the temperature of syngas 21, the higher its saturated water vapor partial pressure. Syngas 21 leaves the gasification device 20 at 30℃~180℃ rather than lower or room temperature. Syngas 21 will carry more moisture into the conversion device 30. This moisture can provide raw material for the water-gas conversion reaction of syngas 21 in the conversion device 30, thereby reducing the amount of water vapor used in the conversion device 30. At the same time, the amount of wastewater in the gasification device 20 is reduced accordingly. Based on the requirements for the H2 and CO content in fresh gas 61, syngas 21 undergoes a water-gas shift reaction in shift unit 30.

[0077]

[0078] Adjust the H2 and CO content in the gas (increase H2 content, decrease CO content). When there are other sources providing H2-rich gas O4 besides the syngas 21 from the gasification unit 20 that provides the CO and / or H2 required by downstream units, such as the process route of biomass gasification to produce syngas and wind and solar power generation to produce hydrogen by water electrolysis, if the amount of H2-rich gas O4 is sufficient and there is no need to increase the H2 in the fresh gas 61 through the water-gas shift reaction of the shift unit 30, then the shift unit 30 can be omitted from the process. The shift gas 31 obtained after adjusting the H2 and CO content enters the first compression unit 40 for pressurization. The gas after being pressurized by the first compression unit 40 is divided into three paths: shift gas 41, shift gas 42, and shift gas 43. Shift gas 41 goes to the purification unit 50 for purification, while shift gas 42 and shift gas 43 are separated from the compressor of the first compression unit 40 at appropriate locations and returned to the gasification unit 20. The shift gas 42, without being cooled by the heat exchanger in the first compression unit 40, is used for reactor fluidization and dust collector backflushing, such as... Figure 1 Fluidizing gas 205 and backflushing gas 206 are used in the process. The shift gas 43 is cooled to room temperature to 40°C by a heat exchanger in the first compression unit 40 and is used for conveying solid particles, such as... Figure 1The gas used in the gasification unit 204 and 207 is a conveying gas. The purified gas 51, after being purified by the purification unit 50 to remove H2S, tar, and all or part of the CO2, is further pressurized by the second compression unit 60 to obtain fresh gas 61. Optionally, when H2-rich gas O4 is present, the purified gas 51 is mixed with H2-rich gas O4 to obtain fresh gas 61. The purification unit 50 can be a low-temperature methanol washing process, and the tar content in the purified gas 51 obtained by the low-temperature methanol washing process is less than 1 mg / Nm3. Biomass feedstock has a high oxygen content, and water is easily generated during biomass gasification. Syngas (shift gas 42) replaces steam as the fluidizing gas in the fluidized bed reactor, significantly reducing the steam consumption of the gasification unit 20 and also reducing the wastewater discharge of the gasification unit 20. The conveying gas required for solid particle conveying in the gasification unit 20 is usually an inert gas. When solid particles need to be fed into the reactor, the pressure of the conveying gas must be higher than the reactor pressure, for example, the pressurized gas after the CO2-rich gas 52 generated in the purification unit 50. The pressure of the CO2-rich gas 52 is typically 0.15–0.05 MPa (gauge pressure), which is much lower than the pressure of the shift gas 31. Replacing the CO2-rich gas 52 with the synthesis gas (shift gas 43) as the conveying gas for solid particles can save the compression power required to pressurize the conveying gas. Compared with the gas pressurized using CO2-rich gas 52, using shift gas 42 as the backflush gas 206 of the dust collector in the gasification device 20 can also save compression power.

[0079] For a specific device, whether pressurization is required between shift gas 31 and shift gas 41, and between purified gas 51 and fresh gas 61, depends on the required pressure of syngas 21 and fresh gas 61. When shift gas 31 does not need to be pressurized to obtain shift gas 41, the first compression device 40 only pressurizes a portion of shift gas 31 to obtain shift gas 42 and shift gas 43.

[0080] like Figure 3As shown, reactor 230 is a fluidized bed type gasifier, divided into a lower section 2301 and an upper section 2303. The upper part of the lower section 2301 is directly connected to the lower part of the upper section 2303. The lower section 2301 has openings including gasifying agent inlet 2311, gasifying agent inlet 2312, gasifying agent inlet 2313, feed inlet 2314, feed inlet 2317, and feed inlet 2318. The upper section 2303 has an opening including gasifying agent inlet 2314. 15. The discharge port 2316, the lower section 2301 of the reactor and the upper section 2303 of the reactor can be one, two or more openings with the same function. The lower section 2301 of the reactor is equipped with a distributor 2304. The distributor 2304 is inverted conical in shape and has a certain number of openings. The gas required for the fluidization of solid particles inside the lower section 2301 of the reactor enters the reactor 230 through the gasifying agent port 2313 and flows through these openings on the distributor 2304. The internal pressure of reactor 230 is 0.1 MPa (gauge pressure) to 7.5 MPa (gauge pressure). Solid biomass 211 from feed unit 210 enters through feed inlet 2314, fly ash 242 from separator 240 enters through feed inlet 2317, and fly ash 281 from fly ash return unit 280 enters through feed inlet 2318. Together with gasifying agent 221 (oxygen, steam, syngas) from gasification unit, they enter through gasifying agent inlets 2311, 2312, and 2313. In the lower section 2301 of reactor, they are converted into syngas containing CO and H2, residual carbon particles, and ash. Syngas contains tar components. Syngas carries the incompletely reacted residual carbon particles, tar, and fly ash into the upper section 2303 of reactor. Ash 232 leaves from the gasifying agent inlet 2312 at the bottom of the lower section 2301 of reactor and enters the slag discharge unit 250. The temperature in the area above the distributor 2304 in the lower section 2301 of the reactor is 750℃~850℃. Too low a temperature is detrimental to biomass reaction and conversion, leading to a higher carbon content in the ash 232 and an increase in the CH4 content in the syngas 231. Too high a temperature may cause slagging of the biomass ash due to its low melting point, thus affecting the continuous and stable operation of the system. In the upper section 2303 of the reactor, the syngas generated in the lower section 2301 and the residual carbon particles it carries undergo a series of reactions with the gasifying agent (containing O2) entering through the gasifying agent port 2315. The resulting syngas 231, carrying a large number of particles (referred to as fly ash in this invention), exits from the discharge port 2316 at the top of the upper section 2303 and enters the separator 240. The overall thermal effect of the reaction in the upper section 2303 of the reactor is exothermic. Therefore, the temperature of the upper section 2303 of the reactor is higher than that of the lower section 2301 of the reactor. The internal temperature of the upper section 2303 of the reactor is 950℃~1050℃. The increase in temperature is conducive to the full conversion of carbon elements in tar and particles into small molecule gas products, effectively improving the gasification efficiency and gas production rate of biomass.The diameter of the upper section 2303 of the reactor is larger than that of the lower section 2301 of the reactor, which makes the gas flow velocity in the upper section 2303 lower than that in the lower section 2301 of the reactor. The reduction in gas flow velocity helps to increase the residence time of the material and reduce the particle mass carried by the synthesis gas 231. Figure 3 The diagram does not show all the openings of reactor 230.

[0081] The pressurized gasification process of this invention is suitable for the production of fuel gas or syngas from solid biomass via fluidized bed pressurized gasification. It is particularly effective under conditions of high oxygen content, high alkali metal content in biomass, and the need for steam in methanol synthesis.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biomass pressurized gasification system, characterized in that, Used for pressurized gasification of biomass, including: The feeding unit is used to add biomass to the reactor; The air intake unit controls the entry of the gas and fluidizing gas required for the biomass gasification reaction into the reactor. The reactor converts biomass and fly ash into syngas and ash residue; A separator for receiving the synthesis gas exiting from the top of the reactor; The waste heat recovery unit is used to receive the syngas after it leaves the separator, cool the syngas, and recover heat at the same time. A slag discharge unit is used to receive the ash slag discharged from the bottom of the reactor; The dust removal unit separates the syngas from the waste heat recovery unit into gas and particles; The water washing and cooling unit receives the syngas after particle separation, and washes and cools the syngas with water before sending it to the downstream device. It also includes a fly ash return unit for receiving particles separated and collected by the dust removal unit; The gas required for the biomass gasification reaction and the fluidizing gas in the fluidizing gas are syngas, water vapor, or a mixture of syngas and water vapor.

2. The biomass pressurized gasification system according to claim 1, characterized in that, The biomass is fed into the feeding unit, metered, and then added to the reactor through a conveying device under the combined action of the biomass' own gravity and the kinetic energy of the conveying gas. The conveying gas for the biomass is inert gas, syngas, or a mixture of both.

3. The biomass pressurized gasification system according to claim 1, characterized in that, The separator is composed of one or more sets of cyclone separators connected in series, and each set of cyclone separators is a collection of one or more cyclone separators.

4. The biomass pressurized gasification system according to claim 1, characterized in that, The fly ash separated by the separator is returned to the reactor.

5. The biomass pressurized gasification system according to claim 1, characterized in that, The heat exchange in the waste heat recovery unit consists of three stages. The synthesis gas from the separator first exchanges heat with water, water vapor, or a mixture of water and water vapor and is cooled to 650°C to 750°C. Then it is mixed with a quenching medium and cooled to 450°C to 550°C. Finally, it exchanges heat with water, water vapor, or a mixture of water and water vapor and is cooled to 350°C to 400°C before leaving the waste heat recovery unit.

6. The biomass pressurized gasification system according to claim 5, characterized in that, The quenching medium is water, water vapor, syngas, or other gases.

7. The biomass pressurized gasification system according to claim 1, characterized in that, The dust removal unit includes a dust collector and a back-blowing air supply. The filter element of the dust collector is a metal filter or a ceramic filter.

8. The biomass pressurized gasification system according to claim 7, characterized in that, The backflush gas is an inert gas, a synthesis gas, or a mixture of both.

9. The biomass pressurized gasification system according to claim 1, characterized in that, The fly ash collected by the dust removal unit is sent back to the reactor via the fly ash return unit.

10. The biomass pressurized gasification system according to claim 9, characterized in that, In the fly ash return unit, the fly ash is sent back to the reactor under the action of conveying gas, which is either inert gas or syngas.

11. The biomass pressurized gasification system according to any one of claims 1, 2, 6, 8, and 10, characterized in that, The synthesis gas contains CO and H2-rich gas from the dust removal unit, CO and H2-rich gas from the dust removal unit after further treatment, or a mixture of the two.

12. The biomass pressurized gasification system according to claim 1, characterized in that, Syngas from the dust removal unit is cooled by a heat exchanger in the water washing and cooling unit and then enters the water washing tower. After heat and mass transfer with the washing water, the gas exiting the water washing and cooling unit is sent to downstream devices as product gas.

13. The biomass pressurized gasification system according to claim 12, characterized in that, The gas in the water-washing cooling unit is cooled to 30°C to 180°C.

14. The biomass pressurized gasification system according to claim 1, characterized in that, Biomass from the feed unit, fly ash returned from the separator, fly ash from the fly ash return unit, and gasifying agent from the gas inlet unit are converted into syngas containing CO and H2 and ash residue in the reactor.

15. The biomass pressurized gasification system according to claim 1, characterized in that, The reactor is a fluidized bed gasifier, with one or more gasifying agent inlets in the upper and lower sections of the reactor, and the internal pressure of the reactor is 0.1 MPa-7.5 MPa.

16. The biomass pressurized gasification system according to claim 1, characterized in that, The internal temperature of the lower section of the reactor is 750℃~850℃, the internal temperature of the upper section of the reactor is 950℃~1050℃, and the diameter of the upper section of the reactor is larger than the diameter of the lower section of the reactor.

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