Biomass dual-bed gasification apparatus and gasification method

Abstract

The present disclosure provides a biomass double-bed gasification device and a gasification method, and belongs to the technical field of biomass gasification. The biomass double-bed gasification device comprises: a biomass pyrolysis gasification furnace provided with a biomass feeding port, a first solid material inlet located downstream of the biomass feeding port, a first gasification agent inlet located at the bottom of the furnace, and a solid discharge outlet of the second solid material and a gas discharge outlet of the pyrolysis gasification gas located at the top of the furnace; a gasification reactor located downstream of the biomass pyrolysis gasification furnace and provided with a pyrolysis gasification gas duct, a second gasification agent duct, and a gasification outlet for discharging pyrolysis gasification gas and the second gasification agent or the gasification product thereof; and a gasification furnace located downstream of the gasification reactor and connected with the gasification reactor through a nozzle located at the top of the gasification furnace, so as to utilize the sensible heat of the synthesis gas and the ash residue to provide reaction heat for the carbon gasification reaction, thereby generating crude coal gas, hydrocarbon solid fuel and bottom slag.

Description

Technical Field

[0001] This disclosure belongs to the field of biomass gasification technology, and particularly relates to a biomass dual-bed gasification device and gasification method. Background Technology

[0002] Gasification technology is one of the core technologies for the clean and efficient utilization of biomass, and it forms the basis for developing green natural gas, green methanol, and green jet fuels based on biomass as raw materials. Due to the diverse types of biomass and the significant differences in moisture, ash, and volatile matter content, gasification equipment needs to be highly adaptable. Furthermore, the high volatile matter content of biomass generates a large amount of tar during gasification, and the high alkali metal (potassium, sodium) content in biomass ash makes it prone to melting inside the gasifier, leading to slagging and corrosion. Additionally, the viscosity-temperature curve has a steep slope, and the viscosity of the ash varies greatly within a narrow temperature range, making it difficult for slagging to adhere to the water-cooled walls of the fluidized bed.

[0003] Existing biomass gasification technologies suffer from high tar content, easy pipe clogging, and inability to be used as downstream synthesis feedstocks. To address the tar issue, the common current solution is to first gasify the biomass to generate tar, and then remove it through high-temperature partial oxidation (POX) or methods such as water washing, electrostatic precipitation, and adsorption. However, this approach suffers from high processing costs and energy waste. Summary of the Invention

[0004] In view of this, this disclosure provides a biomass dual-bed gasification device and gasification method, aiming to at least partially solve the above-mentioned technical problems. The technical solution provided in this disclosure is as follows.

[0005] As a first aspect of this disclosure, a biomass dual-bed gasification apparatus is provided, comprising: a biomass pyrolysis gasifier, a gasification reactor, and a gasifier.

[0006] A biomass pyrolysis gasification furnace is provided with a biomass feed inlet for biomass materials to enter, a first solid material inlet located downstream of the biomass feed inlet for receiving a first solid material, a first gasifying agent inlet located at the bottom of the furnace for introducing a first gasifying agent, a solid discharge outlet for discharging a second solid material, and a gas discharge outlet located at the top of the furnace for discharging pyrolysis gasification gas. The pyrolysis gasification gas and the second solid material are generated by the pyrolysis gasification of the biomass materials after the biomass materials are preheated and mixed by the first solid material.

[0007] The gasification reactor, located downstream of the biomass pyrolysis gasification furnace, is equipped with a pyrolysis gasification gas duct connected to the gas discharge outlet of the pyrolysis gasification gas, a second gasification agent duct for the second gasification agent to enter, and a gasification outlet for discharging the pyrolysis gasification gas and the second gasification agent or their gasification products.

[0008] The gasifier is located downstream of the gasification reactor and is connected to the gasification reactor through a nozzle located at the top of the gasifier. This allows the syngas and ash generated by the gasification reaction to come into contact with the turbulent third solid material under the impetus of the gas. The sensible heat of the syngas and ash provides the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel, and bottom ash. The third solid material includes bed material and second solid material.

[0009] According to an embodiment of this disclosure, the furnace chamber of the gasifier includes a turbulent fluidization section, which includes, from bottom to top, a dense phase zone, a transition zone, and a dilute phase zone. The transition zone is provided with a first return port for the return of the second solid material, and the nozzle is located at the top of the dilute phase zone. The third solid material is turbulent in the dense phase zone.

[0010] The bottom of the gasifier furnace is also equipped with a ash discharge port for discharging bottom ash, a primary air inlet, and an air distribution unit for supplying primary air into the gasifier furnace; wherein, the air distribution unit includes: an air cap, an air distribution plate, and an air chamber.

[0011] According to an embodiment of this disclosure, the gasifier is further provided with: a connecting section and a conveying section; wherein, the connecting section is connected to a transition zone, and the transition zone is further provided with a connection port connected to the connecting section; the conveying section is connected to the connecting section; the included angle between the connection port and the first return port is 90°-180°, the height of the first return port from the air distribution plate is 0.5m-3m, and the height difference between the connection port and the first return port is 0.5m-3m.

[0012] According to an embodiment of this disclosure, a tactile paving is provided at the end of the connecting section that is far from the connection port; and the connection between the connecting section and the transport section extends along the gas direction, and a secondary air duct for secondary air to enter is provided in the transport section along the gas extension direction.

[0013] The length of the tactile paving is 0.2-1.25 times the diameter of the connecting section. The angle between the axial direction and the horizontal direction of the secondary air duct entering the transport section is ±30°. There are multiple secondary air ducts located on the same horizontal plane and arranged in a tangential circle around the transport section. The tangential circle diameter d of the secondary air duct is between 0.5 times the diameter of the connecting section and 0.80 times the diameter of the section where the center line of the secondary air duct nozzle is located.

[0014] According to embodiments of this disclosure, it further includes: a first gas-solid separator, a first return feeder, and a second return feeder;

[0015] The first gas-solid separator is connected at one end to the outlet of the conveying section and at the other end to the first return inlet of the first return feeder.

[0016] The first return feeder is also equipped with a first return outlet connected to the first solid material inlet of the biomass pyrolysis gasification furnace;

[0017] The second return feeder is provided with a second return inlet connected to the solid discharge outlet of the second solid material of the biomass pyrolysis gasification furnace, and a second return outlet for returning the second solid material to the gasification furnace.

[0018] According to embodiments of this disclosure, the gasification reactor is a gasification burner, comprising: a central channel and an annular channel surrounding the central channel; the central channel is a pyrolysis gasification gas duct, the annular channel is a second gasifying agent duct, and the gasification outlet of the gasification burner is directly connected to the nozzle; or

[0019] The gasification reactor is a non-catalytic reactor equipped with a gasification burner, wherein the gasification outlet of the gasification burner is connected to the inlet of the non-catalytic reactor, and the outlet of the non-catalytic reactor is connected to the nozzle.

[0020] According to an embodiment of this disclosure, a second gas-solid separator is further provided between the gasification burner and the biomass pyrolysis gasification furnace; wherein the second gas-solid separator is provided with a second gasification product inlet, a second solid material outlet, and a second gaseous material outlet; the second gasification product inlet is connected to a gas discharge outlet for discharging pyrolysis gasification gas, the second gaseous material outlet is connected to the central channel of the gasification burner, and the second solid material outlet is connected to a second return port provided in the dilute phase zone.

[0021] According to an embodiment of this disclosure, the gasification reactor is a gas-solid separation gasifier, which includes a gas-solid separation gasification cylinder; wherein, the pyrolysis gasification air duct is tangent to the cylinder, and the second gasification agent air duct is located on the central axis of the cylinder.

[0022] According to an embodiment of this disclosure, the second return feeder is a U-shaped return feeder, comprising: a descending section, a horizontal conveying pipe, and an ascending section; wherein, the biomass pyrolysis gasification furnace is coupled to the descending section of the U-shaped return feeder, multiple sets of conveying air are arranged on the horizontal conveying pipe, and the ascending section is connected to the first return port of the gasification furnace.

[0023] As a second aspect of this disclosure, a biomass dual-bed gasification method is provided, comprising: preheating and mixing biomass material with a first solid material entering the biomass pyrolysis gasifier, and then subjecting the biomass material to a pyrolysis gasification reaction with a first gasifying agent entering the biomass pyrolysis gasifier to generate pyrolysis gasification gas and a second solid material, wherein the second solid material is returned to the gasifier.

[0024] The second gasifying agent and the pyrolysis gasification gas enter the turbulent fluidization section of the gasifier through the nozzles at the top of the gasifier reactor and the gasifier for gasification reaction, or they can undergo gasification reaction in the gasifier reactor and then enter the turbulent fluidization section of the gasifier through the nozzles at the top of the gasifier, so as to crack the tar in the pyrolysis gasification gas through the gasification reaction to produce syngas and ash.

[0025] The syngas and ash generated by the gasification reaction come into contact with the turbulent third solid material under the impetus of the gas, and the sensible heat of the syngas and ash provides heat for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel and bottom ash, wherein the third solid material includes bed material and second solid material.

[0026] According to an embodiment of this disclosure, the gasification reactor is a gasification burner, wherein the second gasifying agent and the pyrolysis gasification gas undergo a gasification reaction, including: the pyrolysis gasification gas and the second gasifying agent are injected into the dilute phase zone of the gasification furnace through the gasification burner and the nozzle at the top of the gasification furnace, mixed, and undergo a gasification reaction.

[0027] According to embodiments of this disclosure, the gasification reactor is a non-catalytic reactor equipped with a gasification burner, wherein the gasification reaction is carried out within the non-catalytic reactor equipped with the gasification burner, comprising:

[0028] The pyrolysis gas and the second gasifying agent enter the non-catalytic reactor through the gasification burner to carry out the gasification reaction.

[0029] According to embodiments of this disclosure, the gasification burner includes a central channel and an annular channel surrounding the central channel. Pyrolysis gasification gas is introduced into the central channel, and a second gasifying agent is introduced into the annular channel. The oxygen content in the second gasifying agent accounts for 40%-80% of the total oxygen content of the gasifying agent in the biomass dual-bed gasification method, and the oxygen concentration in the second gasifying agent is 21%-100%. The oxygen concentration in the first gasifying agent is less than or equal to 21%.

[0030] According to an embodiment of this disclosure, before the pyrolysis gas enters the central channel of the gasification burner, the process further includes: passing the pyrolysis gas into a second gas-solid separator for gas-solid separation, and then passing the separated pyrolysis gas into the central channel of the gasification burner.

[0031] According to an embodiment of this disclosure, the gasification reactor is a gas-solid separation gasifier, wherein the gasification reaction is carried out in the gas-solid separation gasifier, including: pyrolysis gas entering the gas-solid separation gasifier tangentially, and gas-solid separation under the centrifugal action of the gas-solid separation gasifier; the separated pyrolysis gas is located in the central region of the gas-solid separation gasifier, and undergoes a gasification reaction with a second gasifying agent introduced through the center of the gas-solid separation gasifier.

[0032] According to embodiments of this disclosure, the sensible heat of syngas and ash is used to provide the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel and bottom ash. The process includes: syngas and ash are contacted and fully mixed with a third solid material in the dense phase zone of the gasifier; the sensible heat of syngas and ash is used to provide the heat of reaction for the carbon gasification reaction in the presence of primary air, resulting in crude coal gas, hydrocarbon solid fuel and bottom ash.

[0033] The oxygen concentration in the primary air is 15%-45%; the second solid material includes: pyrolyzed char, semi-coke, and bed material; the first solid material includes: semi-coke and bed material.

[0034] According to an embodiment of this disclosure, along the gas flow direction, crude coal gas and hydrocarbon solid fuel enter the connecting section through the connection port provided in the transition zone of the gasifier, and a blind path provided in the connecting section is used to enhance the mixing of crude coal gas and hydrocarbon solid fuel.

[0035] After mixing, the mixture is transported to the conveying section, where secondary air is introduced tangentially to enhance the mixing of the secondary air with the crude coal gas and hydrocarbon solid fuels, and to facilitate the gasification reaction, cracking the tar in the crude coal gas and producing gasification products; and

[0036] Optionally, it may also include: after the gasification reaction, conveying the gasification products to a first gas-solid separator for gas-solid separation to obtain a first solid material, pure syngas and fly ash;

[0037] The secondary air is introduced into the conveying section in a tangential manner. The oxygen concentration in the secondary air is 21%-60%, and the flow velocity of the secondary air is 30m / s-100m / s. The first solid material enters the biomass pyrolysis gasification furnace through the first return feeder.

[0038] According to embodiments of this disclosure, the second solid material is returned to the gasifier via the second return feeder; or the biomass pyrolysis gasifier is coupled with the second return feeder, which is a U-shaped return feeder. The second solid material pyrolyzed in the biomass pyrolysis gasifier is transported through the horizontal conveying pipe in the U-shaped return feeder to the rising section of the U-shaped return feeder and returned to the gasifier for carbon gasification reaction.

[0039] Based on the above technical solution, the biomass dual-bed gasification device and gasification method provided in this disclosure have at least one of the following beneficial effects:

[0040] (1) In this disclosure, by designing the positions of the biomass feed port, the first solid material inlet, and the first gasifying agent inlet in the biomass pyrolysis gasifier, the biomass material entering the biomass pyrolysis gasifier is preheated by the first solid material. The preheated biomass material reacts with the first gasifying agent entering the pyrolysis gasifier to produce pyrolysis gas and the second solid material. The pyrolysis gas contains a high tar content and cannot be used as a raw material for downstream syngas. Therefore, this disclosure proposes to connect the biomass pyrolysis gasifier to the gasification reactor, and to install a second gasifying agent duct on the gasification reactor for the second gasifying agent to enter, so that the pyrolysis gas and the second gasifying agent react in the gasification reactor to fully crack the tar in the pyrolysis gas. The resulting syngas and entrained ash are then introduced into the gasifier through the nozzle at the top of the gasifier. Alternatively, a biomass pyrolysis gasifier and a gasification reactor can be connected, with the gasification reactor connected to the gasifier via a nozzle at the top of the gasifier. This allows the pyrolysis gas and the second gasifying agent to be fed into the gasifier, achieving the gasification reaction and producing syngas and ash. Furthermore, the syngas and ash in the gasifier, propelled by the gas, come into contact with turbulent third solid material. Under intense turbulent fluidization, the ash is rapidly dispersed, preventing ash adhesion and slagging. Simultaneously, the sensible heat of the syngas and ash undergoes rapid mass and heat transfer and carbon gasification under intense turbulence, producing crude coal gas, hydrocarbon solid fuel, and bottom ash, significantly reducing the oxygen and energy consumption of the unit.

[0041] (2) This disclosure achieves the decoupling of biomass pyrolysis carbonization and carbon gasification through a dual fluidized bed design of the biomass pyrolysis gasifier and the gasifier. In the biomass pyrolysis gasifier, the heat carried by the first solid material and a small amount of oxygen-enriched reaction heat are sufficient to meet the pyrolysis and small-scale gasification of the biomass material. This fully decomposes the tar in the pyrolysis gasification gas while avoiding slagging due to the high alkali metal content in the biomass material. In the gasifier, the sensible heat of the syngas and ash is fully utilized to provide reaction heat for the carbon gasification reaction of the turbulent third solid material within the gasifier. This cools the ash while preventing it from agglomerating into large slag lumps, and also helps to prevent overheating of the gasifier's top lining. The device provided in this disclosure achieves the characteristics of tar-free, low-slagging, and high conversion rate in biomass material gasification. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the biomass dual-bed gasification device in an embodiment of this disclosure;

[0043] Figure 2 This is a schematic diagram of the structure of the biomass pyrolysis gasification furnace in an embodiment of this disclosure;

[0044] Figure 3 This is a schematic diagram showing the connection between the connecting section and the transport section in an embodiment of this disclosure;

[0045] Figure 4 This is a schematic diagram of the secondary air duct layout structure;

[0046] Figure 5 This is a schematic diagram of the structure of the non-catalytic reactor in the embodiments of this disclosure;

[0047] Figure 6A This is a cross-sectional view of the gas-solid separation vaporizer in the XX direction in an embodiment of this disclosure;

[0048] Figure 6B This is a top view of the gas-solid separation vaporizer in an embodiment of this disclosure;

[0049] Figure 7 This is a schematic diagram of the coupling structure between the U-shaped return feeder and the biomass pyrolysis gasification furnace in an embodiment of this disclosure.

[0050] [Explanation of Labels in the Attached Image]

[0051] 1-Gasifier, 1-1-Turbulent fluidization section, 1-2-Connecting section, 1-3-Transport section, 11-Primary air inlet, 12-Slag discharge port, 13-First return material port, 14-Nozzle, 15-Outlet of transport section;

[0052] 2-First gas-solid separator, 21-First gasification product inlet, 22-First solid material outlet, 23-First gaseous material outlet;

[0053] 3-First return feeder, 31-First return feed inlet, 32-First return feed outlet;

[0054] 4-Biomass pyrolysis gasification furnace, 41-First solid material inlet, 42-Biomass feed inlet, 43-Solid discharge outlet, 44-Gas discharge outlet, 45-First gasifying agent inlet;

[0055] 5-Second return feeder, 51-Second return feed inlet, 52-Second return feed outlet;

[0056] 6 - Non-catalyst reactor; 61 - Inlet of non-catalyst reactor; 62 - Outlet of non-catalyst reactor;

[0057] 7-Gas-solid separation vaporizer;

[0058] A - First solid material, B - Biomass material, C - Second solid material, PG - Pyrolysis gasification gas, F - Bottom ash, G - Pure syngas, H - Fly ash;

[0059] g1 - First gasifying agent, g2 - Second gasifying agent, g3 - Primary air, g4 - Secondary air. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0061] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0062] Gasification technology is classified into three categories based on the feeding method and gas-solid flow pattern: fixed bed, fluidized bed, and entrained gasification. Fixed bed gasification, due to its lower gas outlet temperature and the downward movement of materials, results in higher tar content in biomass gasification. On a large scale, it is prone to uneven combustion, leading to instability in gas composition and gasifier operation. Fluidized bed gasification, employing a gas-solid fluidization process, features uniform temperature distribution, wide feedstock adaptability, large gasification scale, and low cost, and is generally considered the ideal gasifier type for biomass gasification. Entrained gasification has a higher gasification temperature and lower tar and other contaminant content in the gas. However, entrained gasification has higher pulverization costs, and the steeper viscosity-temperature curve of the ash makes it less prone to slag adhesion and alkali metal corrosion, further contributing to its higher gasification cost. Comparing the three types of gasification technology, fluidized bed gasification, with its wide feedstock adaptability, large gasification scale, and low gasification cost, is more suitable for biomass gasification. However, existing fluidized bed gasification technologies suffer from problems such as high tar content, easy pipe blockage, and inability to be used as downstream syngas feedstock.

[0063] To address the tar issue, a conventional method involves adding high-temperature partial oxidation (POX) to a fluidized bed gasification unit. This raises the temperature of the syngas generated in the fluidized bed to approximately 1250°C, and oxygen is introduced to initiate a high-temperature non-catalytic reforming reaction, reforming the tar in the syngas into carbon monoxide (CO), carbon dioxide (CO2), and hydrogen (H2). While adding high-temperature non-catalytic reforming can fully convert the tar in the syngas, it also consumes valuable components in the syngas, converting them into heat and raising the reaction temperature to 1250°C. Furthermore, the steam generated from the high-temperature syngas through boiler waste heat recovery does not contribute to the gasification reaction, increasing the cost of fluidized bed gasification of biomass materials and also increasing oxygen consumption.

[0064] In response, this disclosure provides a biomass dual-bed gasification device and gasification method. Through structural design, the pyrolysis and carbonization of biomass materials are carried out in two fluidized beds, achieving the advantages of biomass material gasification with no tar, less slag, and lower energy consumption and oxygen consumption.

[0065] Figure 1 This is a schematic diagram of the biomass dual-bed gasification device in an embodiment of this disclosure.

[0066] like Figure 1 As shown, the present invention discloses a biomass dual-bed gasification device, comprising: a biomass pyrolysis gasifier 4, a gasifier 1, and a gasification reactor.

[0067] Figure 2 This is a schematic diagram of the structure of the biomass pyrolysis gasification furnace in an embodiment of this disclosure.

[0068] like Figure 2 As shown, the biomass pyrolysis gasification furnace 4 is provided with a biomass feed port 42 for biomass material B to enter, a first solid material inlet 41 located downstream of the biomass feed port 42 for receiving the first solid material A, a first gasifying agent inlet 45 located at the bottom of the furnace for supplying the first gasifying agent g1, a solid discharge outlet 43 for discharging the second solid material C, and a gas discharge outlet 44 located at the top of the furnace for discharging pyrolysis gasification gas PG. The pyrolysis gasification gas PG and the second solid material C are generated by mixing and preheating the biomass material B with the first solid material A, followed by pyrolysis gasification of the biomass material B and the first gasifying agent g1.

[0069] The gasification reactor is located downstream of the biomass pyrolysis gasification furnace 4. It is equipped with a pyrolysis gasification gas duct connected to the gas discharge outlet 44 of the pyrolysis gasification gas PG, a second gasification agent duct for the second gasification agent g2 to enter, and a gasification outlet for discharging the pyrolysis gasification gas PG and the second gasification agent g2 or their gasification products.

[0070] Gasifier 1 is located downstream of gasification reactor and connected to gasification reactor via nozzle 14 at the top of gasifier 1. This allows the syngas and ash generated by the gasification reaction to come into contact with turbulent third solid material under the impetus of the gas. The sensible heat of the syngas and ash provides the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel and bottom ash F. The third solid material includes bed material and second solid material C.

[0071] In the embodiments of this disclosure, a first solid material inlet 41 is located downstream of the biomass feed inlet 42 in the biomass pyrolysis gasifier 4, so that the biomass material B entering the biomass pyrolysis gasifier 4 is mixed and preheated with the first solid material A. A first gasifying agent inlet 45 is provided at the bottom of the biomass pyrolysis gasifier 4, so that the first gasifying agent g1 reacts with the preheated biomass material B to produce pyrolysis gas PG and a second solid material C. A solid discharge outlet 43 is also provided at the bottom of the biomass pyrolysis gasifier 4 for discharging the second solid material C, so that the second solid material C can be returned to the gasifier 1 to participate in the carbon gasification reaction. A gas discharge outlet 44 is provided at the top of the biomass pyrolysis gasifier 4 for discharging the pyrolysis gas PG, so that the pyrolysis gas PG can enter the gasification reactor for gasification reaction. Furthermore, a second gasifying agent duct is installed on the gasification reactor to allow the second gasifying agent g2 to enter. Within the gasification reactor, a non-catalytic gasification reaction is achieved between the pyrolysis gasification gas PG and the second gasifying agent g2, fully cracking the tar in the pyrolysis gasification gas PG to obtain pure syngas and ash. This syngas is then introduced into the gasification furnace 1 through the nozzle 14 at the top of the gasification furnace 1. Alternatively, the biomass pyrolysis gasification furnace 4, the gasification reactor, and the nozzle 14 at the top of the gasification furnace 1 are connected sequentially. The pyrolysis gasification gas PG and the second gasifying agent g2 from the gasification reactor are injected into the gasification furnace 1 through the nozzle 14 to undergo a gasification reaction, producing syngas and ash. In gasifier 1, the syngas and ash are brought into contact with the turbulent third solid material under the impetus of the gas. Under the intense turbulent fluidization, the ash is rapidly dispersed, avoiding ash adhesion and slagging. At the same time, the sensible heat of the syngas and ash is used to rapidly transfer mass and heat and carry out carbon gasification reaction under intense turbulence, producing crude coal gas, hydrocarbon solid fuel and bottom ash, which significantly reduces the oxygen consumption and energy consumption of the unit.

[0072] Specifically, continue as Figure 2 As shown, the biomass pyrolysis gasification furnace 4 is a fluidized bed composed of a truncated cone (smaller at the bottom and larger at the top) and an enlarged section at the upper part of the cone. The first gasifying agent g1 is introduced from the bottom of the biomass pyrolysis gasification furnace 4 to ensure that the incoming biomass material B is fully fluidized at the bottom of the furnace and thoroughly mixed with the biomass material B entering through the biomass feed inlet 42 and the first solid material A entering through the first solid material inlet 41. The first solid material inlet 41 is located downstream of the biomass feed inlet 42 to preheat the biomass material B using the heat from the first solid material A. The preheated biomass material B then undergoes a pyrolysis gasification reaction with the first gasifying agent g1, removing volatiles from the biomass material B. The amount of volatiles removed accounts for 50%-85% of the volatile matter content in biomass industrial analysis. The top of the biomass pyrolysis gasification furnace 4 is equipped with a gas discharge outlet 44 for discharging the pyrolysis gasification gas PG, which is connected to the gasification reactor via a pipeline.

[0073] Continue as Figure 1 As shown, the furnace of gasifier 1 includes a turbulent fluidization section 1-1, which is a fluidized bed composed of a truncated cone (larger at the top and smaller at the bottom) and a cylinder at the top of the cone, serving as the main gasification reaction zone for carbon. The inclination angle of the truncated cone at the bottom of the turbulent fluidization section 1-1 is 68°-85°. At the bottom of gasifier 1, there is a ash discharge port 12 for discharging bottom ash F, a primary air inlet 11, and an air distribution unit for supplying primary air g3 into the furnace of gasifier 1. The air distribution unit includes an air cap, an air distribution plate, and an air chamber. Further, the turbulent fluidization section 1-1 includes, from bottom to top, a dense phase zone, a transition zone, and a dilute phase zone. The transition zone is provided with a first return port 13 for the return of the second solid material C, so that the third solid material, composed of the second solid material C and the bed material, turbulently moves in the dense phase zone of gasifier 1 and undergoes a carbon gasification reaction in the presence of primary air g3. Nozzle 14 is located at the top of the dilute phase zone, so that the pyrolysis gasification gas PG and the second gasifying agent g2 can fully utilize the space above the turbulent fluidization section 1-1 for gasification reaction, fully cracking the tar in the pyrolysis gasification gas PG to produce high-temperature syngas and high-temperature ash (above 1000℃), while reducing heat loss. The dense phase zone of the turbulent fluidization section 1-1 has a high particle concentration, more intense turbulent fluidization, and a large internal circulation volume. Utilizing the high heat and mass transfer efficiency of gasifier 1 (i.e., fluidized bed), the high-temperature syngas and ash produced by the gasification reaction come into contact with the turbulent third solid material in the dense phase region under the action of gas driving force. Under the intense turbulent fluidization, the ash is rapidly dispersed, avoiding the agglomeration into large slag lumps, thus solving the slagging problem existing in traditional fluidized bed biomass gasification. At the same time, the sensible heat of syngas and ash is transferred to the third solid material to provide the reaction heat for carbon gasification reaction, realizing efficient energy utilization and significantly reducing the oxygen consumption and energy consumption of the system. The bottom ash F produced by the carbon gasification reaction is discharged from the ash discharge port 12 at the bottom of the furnace of gasifier 1.

[0074] Figure 3 This is a schematic diagram illustrating the connection between the connecting section and the transport section in an embodiment of this disclosure. Figure 4 This is a schematic diagram of the secondary air duct layout.

[0075] Continue as Figure 1 , Figure 3 As shown, in addition to the turbulent fluidization section 1-1, the gasifier 1 also includes a connecting section 1-2 and a conveying section 1-3. The connecting section 1-2 connects the turbulent fluidization section 1-1 and the conveying section 1-3. The transition zone, in addition to the first return port 13, also has a connection port connected to the connecting section 1-2, thus connecting the turbulent fluidization section 1-1 to the connecting section 1-2. A tactile paving is provided at the end of the connecting section 1-2 furthest from the connection port. The length of the tactile paving is 0.2-1.25 times the diameter of the connecting section 1-2 (e.g., ...). Figure 3(As shown). Further, the included angle between the connecting port and the first return port 13 is 90°-180°, the height of the first return port 13 from the air distribution plate is 0.5m-3m, and the height difference between the connecting port and the first return port 13 is 0.5m-3m. In the embodiments of this disclosure, the conveying section 1-3 and the turbulent fluidization section 1-1 are connected by the connecting section 1-2, so that the crude coal gas generated by the gasification reaction in the dense phase zone of the gasifier 1 furnace and the entrained solid particles (such as hydrocarbon solid fuel, semi-coke, second solid material, etc.) can enter the connecting section 1-2 through the connecting port from the transition zone and / or dilute phase zone sidewall of the turbulent fluidization section 1-1 and reach the conveying section 1-3. By setting a blind channel at the end of the connecting section 1-2, a buffer zone can be provided for the large-angle deflection of solid particles entering the connecting section 1-2, and at the same time, the mixing and distribution uniformity between gas and solid can be enhanced, avoiding the segregation of solid particles in the connecting section 1-2 and the problem of coking at the bottom. By setting the angle and height difference between the connection port and the first return port 13, the carbon gasification reaction is ensured to proceed smoothly, while the pressure inside the gasifier 1 is balanced, reducing the amount of solid particles in the furnace of the gasifier 1 that enter the connection section 1-2 through the connection port under the action of gas entrainment.

[0076] Continue as Figure 3 As shown, the connection between connecting section 1-2 and transport section 1-3 extends along the gas direction. Transport section 1-3 is equipped with a secondary air duct for secondary air g4 to enter along this gas extension direction. The angle α between the axial direction and the horizontal direction of the secondary air g4 entering transport section 1-3 is ±30°. The secondary air duct is located 0.1m to 1m away from the connection between transport section 1-3 and connecting section 1-2. There are multiple secondary air ducts located on the same horizontal plane and arranged tangentially upwards around transport section 1-3 (e.g., ...). Figure 3-4 As shown in the figure, the tangential diameter d of the secondary air duct is between 0.5 times the diameter of the connecting section 1-2 and 0.80 times the diameter d of the cross-section where the center line of the secondary air duct nozzle is located. In the embodiments of this disclosure, the crude coal gas produced by the carbon gasification reaction can carry some solid particles into the conveying section 1-3 through the connecting section 1-2. As the diameter of the connecting section 1-2 to the conveying section 1-3 increases, the gas flow velocity decreases, and the solid particles will backflow and mix at the connection between the connecting section 1-2 and the conveying section 1-3, resulting in an increase in particle concentration. At this time, the secondary air g4 is introduced in a tangential shape, which can enhance the mixing and gasification reaction between the secondary air g4 and the solid particles carried by the crude coal gas. At the same time, it can change the gas-solid ring structure, so that the gas and solid present a swirling upward flow, enhance the mass transfer, heat transfer and gasification reaction between the gas and solid, and further reduce the tar content in the crude coal gas.

[0077] Continue as Figure 1 As shown, the biomass dual-bed gasification device also includes: a first gas-solid separator 2, a first return feeder 3, and a second return feeder 5.

[0078] The first gas-solid separator 2 is connected at one end to the outlet 15 of the conveying section and at the other end to the first return inlet 31 of the first return feeder 3. Specifically, the first gas-solid separator 2 is provided with a first gasification product inlet 21, a first gaseous material outlet 23, and a first solid material outlet 22. The first gasification product inlet 21 is connected to the outlet 15 of the conveying section to send the solid particles entrained in the crude coal gas and the gasification products after the gasification reaction with the secondary air g4 into the first gas-solid separator 2 for gas-solid separation. The resulting first solid material A leaves the first gas-solid separator 2 through the first solid material outlet 22, while the separated pure syngas G and fly ash H leave the first gas-solid separator 2 through the first gaseous material outlet 23. Furthermore, the first gas-solid separator 2 can be a high-efficiency cyclone separator with a separation efficiency of ≥99%, and other high-efficiency gas-solid separators can also be used.

[0079] The first return feeder 3 is provided with a first return inlet 31 and a first return outlet 32. The first return inlet 31 is connected to the first solid material outlet 22 of the first gas-solid separator 2, and the first return outlet 32 ​​is connected to the first solid material inlet 41 of the biomass pyrolysis gasification furnace 4. The first solid material A is introduced into the first return feeder 3 through the first return inlet 31 and transported to the biomass pyrolysis gasification furnace 4 through the first return outlet 32 ​​to preheat the biomass material B. The first return feeder 3 can avoid problems such as gas leakage and poor return flow during the return process.

[0080] The second return feeder 5 is equipped with a second return inlet 51 and a second return outlet 52. The second return inlet 5 is connected to the solid discharge outlet 43 of the biomass pyrolysis gasifier 4, and the second return outlet 52 is connected to the first return port 13 in the gasifier 1. This allows the second solid material C to be conveyed into the second return feeder 5, discharged through the second return outlet 52, and returned to the gasifier 1 through the first return port 13, thus ensuring the smooth return of the second solid material C. Furthermore, the first return feeder 3 and the second return feeder 5 can be non-mechanical return feeders, such as any one of U-shaped, J-shaped, N-shaped, or L-shaped return feeders, or they can be jet conveyors, with a U-shaped return feeder being preferred.

[0081] In the first embodiment of this disclosure, when the gasification reactor is a gasification burner, the gasification burner is located downstream of the biomass pyrolysis gasifier 4, and the gasification outlet of the gasification burner is connected to the gasifier 1 through the nozzle 14 at the top of the gasifier 1. The gasification burner is a two-channel burner, including a central channel and an annular channel surrounding the central channel. The central channel is a pyrolysis gasification gas duct, serving as the channel for the flow of pyrolysis gasification gas PG; the annular channel is a second gasifying agent duct, serving as the channel for the flow of the second gasifying agent g2. The pyrolysis gasification gas PG and the second gasifying agent g2 are injected into the dilute phase zone of the gasifier 1 through the gasification burner and the nozzle 14 at the top of the gasifier 1, where they mix and undergo a gasification reaction to produce syngas and ash.

[0082] The pyrolysis gas PG discharged from the top of the biomass pyrolysis gasifier 4 may carry some solid particles, which may cause the gasification reaction to produce a large amount of ash and slag, thus affecting the stability of the long-term operation of the turbulent fluidization section 1-1.

[0083] In response, the second embodiment of this disclosure proposes to install a second gas-solid separator between the gasification burner and the biomass pyrolysis gasifier 4.

[0084] The second gas-solid separator is provided with a second gasification product inlet, a second solid material outlet, and a second gaseous material outlet. The second gasification product inlet is connected to a gas discharge outlet 44 for discharging pyrolysis gasification gas PG. The second gaseous material outlet is connected to the central channel of the gasification burner. The second solid material outlet is connected to a second return port located in the dilute phase zone of the gasifier 1, and the return position of the second return port is higher than the position of the first return port 13 in the turbulent fluidization section 1-1. In the second embodiment of this disclosure, the pyrolysis gasification gas PG undergoes gas-solid separation before entering the gasification burner. The solid particles (such as part of the second solid material) collected by the gas-solid separator can be returned to the dilute phase zone of the turbulent fluidization section 1-1 via the return port for carbon gasification reaction. Thus, after the pyrolysis gas PG undergoes gas-solid separation in the second gas-solid separator, the solid particle content in the pyrolysis gas PG entering the gasification burner is significantly reduced. This reduces the oxygen consumption required for the high-temperature gasification reaction (1000℃) in the furnace of gasifier 1, reduces the consumption of syngas during the non-catalytic cracking of tar, avoids the formation of a large amount of ash in gasifier 1, further avoids slagging problems, and further improves the thermal efficiency of biomass gasification.

[0085] In both the first and second embodiments described above, pyrolysis gas PG and the second gasifying agent g2 are introduced into the nozzle 14 at the top of the gasifier 1 through a gasifying burner, and then injected into the dilute phase zone of the gasifier 1 through the nozzle 14 for mixing and gasification reaction. However, the gasification reaction time in the dilute phase zone is relatively short, and the tar in the pyrolysis gas PG may not be completely removed. To address this, this disclosure introduces a non-catalytic reactor 6.

[0086] Figure 5 This is a schematic diagram of the structure of the non-catalytic reactor in an embodiment of this disclosure.

[0087] In the third embodiment of this disclosure, the gasification reactor used is a non-catalytic reactor with a gasification burner, namely, a gasification burner and a non-catalytic reactor 6. The non-catalytic reactor 6 is provided with an inlet 61 and an outlet 62. The gasification burner in the third embodiment has the same structure as that in the first embodiment, and will not be described in detail here. The inlet 61 of the non-catalytic reactor 6 is connected to the gasification outlet of the gasification burner, and the outlet 62 of the non-catalytic reactor 6 is connected to the nozzle 14 at the top of the gasifier 1. The pyrolysis gasification gas PG and the second gasifying agent g2 are introduced into the non-catalytic reactor 6 through the gasification burner for high-temperature gasification reaction. The resulting syngas and ash are discharged through the outlet 62 of the non-catalytic reactor and then enter the turbulent fluidization section 1-1 through the nozzle 14 at the top of the gasifier 1. The internal reaction temperature of the non-catalytic reactor 6 is 950-1300℃. In the third embodiment of this disclosure, the pyrolysis gasification gas PG and the second gasifying agent g2 undergo high-temperature non-catalytic reforming (i.e., gasification reaction) in the non-catalytic reactor 6 via a gasification burner. The non-catalytic reactor 6 extends the gasification reaction time, allowing for complete removal of tar from the pyrolysis gasification gas PG and the crude syngas generated by the gasification reaction. Compared to the gasification reaction conducted in the dilute phase region of the turbulent fluidization section 1-1, the tar gasification reaction in the non-catalytic reactor 6 is more complete and thorough, resulting in a higher tar removal efficiency.

[0088] As an alternative, the gasification reactor can also be a gas-solid separation gasifier, which is connected to the nozzle 14. Figure 6A This is a cross-sectional view of the gas-solid separation vaporizer in the XX direction according to an embodiment of this disclosure. Figure 6B This is a top view of the gas-solid separation vaporizer in an embodiment of this disclosure.

[0089] In the fourth embodiment of this disclosure, as Figures 6A-6BAs shown, the gas-solid separation gasifier 7 includes a gas-solid separation gasification cylinder, a pyrolysis gasification gas duct, and a second gasifying agent duct. The pyrolysis gasification gas duct is tangential to the upper side wall of the cylinder, and the second gasifying agent duct is located on the central axis of the cylinder. The pyrolysis gasification gas duct serves as the flow channel for the pyrolysis gasification gas PG, and the second gasifying agent duct serves as the flow channel for the second gasifying agent g2. The pyrolysis gasification gas PG from the biomass pyrolysis gasification furnace 4 enters the gas-solid separation gasifier 7 tangentially through the pyrolysis gasification gas duct, where the pyrolysis gasification gas PG and the entrained carbon-containing solid material (such as the second solid material) are separated. Under the action of centrifugal force, the carbon-containing solid material rotates and moves downward along the inner wall of the cylinder, while the separated pyrolysis gasification gas PG is located in the central region of the gas-solid separation gasifier 7. At this point, the second gasifying agent g2 is introduced from the central axis of the gas-solid separation gasifier. The second gasifying agent g2 preferentially contacts the pyrolysis gasified gas PG after gas-solid separation and carries out a gasification reaction. Then, by introducing a small amount of oxygen, the tar in the pyrolysis gasified gas PG can be completely cracked.

[0090] According to the embodiments of this disclosure, in the above embodiments, the second return feeder 5 can be connected to the gasifier 1 through the return feed leg, or the second return feeder 5 can be coupled together with the biomass pyrolysis gasifier 4.

[0091] Figure 7 This is a schematic diagram of the coupling structure between the U-shaped return feeder and the biomass pyrolysis gasification furnace in an embodiment of this disclosure.

[0092] like Figure 7 As shown, in the biomass dual-bed gasification device of the fifth embodiment of this disclosure, the second return feeder 5 is a U-shaped return feeder. This U-shaped return feeder includes a descending section, a horizontal conveying pipe, and an ascending section. The biomass pyrolysis gasification furnace 4 is coupled to the descending section of the U-shaped return feeder, and multiple sets of conveying air are arranged on the horizontal conveying pipe of the U-shaped return feeder. The ascending section of the U-shaped return feeder is connected to the first return port 13 of the gasification furnace. The ratio of the length of the horizontal conveying pipe of the U-shaped return feeder to the inner diameter of the ascending section is 0.5 to 3, and the ratio of the height of the ascending section to its inner diameter is 1 to 4. By coupling the descending section of the U-shaped return feeder to the biomass pyrolysis gasification furnace 4, the conveying of the second solid material C can be enhanced and controlled, and the applicability of solid particles is broadened.

[0093] As a second aspect of this disclosure, a biomass dual-bed gasification method is provided, which can be performed by the biomass dual-bed gasification apparatus described in the first to fifth embodiments above.

[0094] Specifically, the biomass dual-bed gasification method includes: using the first solid material A entering the biomass pyrolysis gasifier 4 to preheat and mix the biomass material B, then the biomass material B reacts with the first gasifying agent g1 entering the biomass pyrolysis gasifier 4 to produce pyrolysis gas PG and the second solid material C, and the second solid material C is returned to the gasifier 1.

[0095] The second gasifying agent g2 and the pyrolysis gasification gas PG enter the turbulent fluidization section 1-1 of the gasifier 1 through the nozzle 14 at the top of the gasifier reactor and the gasifier 1 to carry out the gasification reaction, or carry out the gasification reaction in the gasifier reactor and then enter the turbulent fluidization section 1-1 of the gasifier 1 through the nozzle 14 at the top of the gasifier 1, so as to crack the tar in the pyrolysis gasification gas PG through the gasification reaction to produce syngas and ash.

[0096] The syngas and ash generated by the gasification reaction come into contact with the turbulent third solid material under the impetus of the gas, and the sensible heat of the syngas and ash provides the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel and bottom ash F, wherein the third solid material includes bed material and second solid material C.

[0097] In the embodiments of this disclosure, the structure of the biomass dual-bed gasification device is designed to decouple biomass pyrolysis carbonization and carbon gasification through a dual fluidized bed of biomass pyrolysis gasifier 4 and gasifier 1, that is, to separate tar gasification and biomass pyrolysis carbon gasification. Inside the biomass pyrolysis gasifier 4, the heat carried by the first solid material A and a small amount of oxygen-enriched reaction heat satisfy the pyrolysis and a small amount of gasification of biomass material B, generating pyrolysis gas PG and a second solid material C. The pyrolysis gas PG carrying tar enters the gasification reactor, where the tar is completely converted through a high-temperature (1000℃-1300℃) non-catalytic gasification reaction. This solves the tar problem in the gasification of biomass material B from the source, avoiding the problem of excessive oxygen consumption caused by the traditional method of first gasifying and then gasifying all the syngas and entrained solid particles through high-temperature (1000℃-1300℃) non-catalytic reforming, which affects the economic efficiency of biomass gasification to syngas production. The char (i.e., the second solid material) generated from the pyrolysis of biomass materials is returned to gasifier 1 for carbon gasification. Simultaneously, the high-temperature syngas and high-temperature ash (1000℃-1300℃) generated from non-catalytic gasification are thoroughly mixed with the low-temperature turbulent third solid material at the bottom of the furnace in the turbulent fluidization section 1-1 of gasifier 1 and cooled. This effectively utilizes the sensible heat of the high-temperature syngas and ash for low-temperature carbon gasification. Furthermore, the turbulent fluidization disperses the high content of molten alkali metals in biomass material B, effectively solving the problem of biomass ash slagging.

[0098] According to embodiments of this disclosure, the sensible heat of syngas and ash is used to provide the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel, and bottom ash. This includes: syngas and ash contacting and thoroughly mixing with a third solid material in the dense phase zone of gasifier 1; using the sensible heat of syngas and ash to provide the heat of reaction for the carbon gasification reaction in the presence of primary air g3; and gasifying the ash and the third solid material to obtain crude coal gas, hydrocarbon solid fuel, and bottom ash F. The first solid material A originates from the first return feeder 3 and includes: semi-coke and bed material; the second solid material is generated by the pyrolysis and gasification of biomass material B and includes: pyrolyzed char, semi-coke, and bed material; the third solid material includes: bed material and the second solid material.

[0099] According to embodiments of this disclosure, in the biomass pyrolysis gasifier 4, to ensure sufficient fluidization of biomass material B at the bottom of the gasifier 4, the apparent flow velocity at the bottom of the biomass pyrolysis gasifier 4 is 1.5-4 m / s. The first gasifying agent g1 is selected from any one of water vapor, a mixture of water vapor and air, or a mixture of oxygen and water vapor, and the oxygen concentration in the first gasifying agent g1 is controlled below 21%. To reduce the solid material entrained in the pyrolysis gas PG, the apparent velocity of the enlarged section of the biomass pyrolysis gasifier 4 is 0.5-1.5 m / s.

[0100] According to embodiments of this disclosure, a bottom fluidized bed gasification reaction zone of a biomass dual-bed gasification device is constructed using an air distribution unit at the bottom of the gasifier 1 furnace. Within this bottom fluidized bed gasification reaction zone, the apparent velocity in the bottom dense phase region of the turbulent fluidization section 1-1 is 2.5 m / s to 6 m / s, and the apparent velocity in the upper dilute phase region is 0.8 m / s to 2 m / s. The fluidization velocity in the bottom fluidized bed gasification reaction zone gradually decreases upwards along the axial direction. This ensures sufficient fluidization of the third solid material at the bottom of the gasifier 1 furnace, resulting in strong material diffusion capacity and high heat and mass transfer rates, while also ensuring a large amount of internal circulation. The lower apparent fluidization velocity in the dilute phase zone reduces the ability of the gas (crude gas) to entrain solid particles, thereby lowering the temperature at the top of the turbulent fluidization section 1-1 in the gasifier 1 furnace. This cools the high-temperature syngas and ash ejected from the nozzle 14 at the top of the gasifier 1, preventing the formation of large amounts of carbon-coated solid material when it reaches the fluidized bed surface, and effectively preventing the ash from agglomerating into large slag lumps. The turbulent gas-solid flow field constructed in the bottom fluidized bed gasification reaction zone allows the viscous ash coming down from the top to be rapidly dispersed and cooled under the action of sufficient fluidization and strong internal circulation of solid material, avoiding coking problems. It also transfers the sensible heat of the syngas and ash to the gasified carbon, fully utilizing the sensible heat of gasification, significantly improving the thermal efficiency of biomass gasification, and reducing oxygen consumption. In addition, the lower gas velocity in the dilute phase region also prevents viscous solid particles (such as ash, secondary solid materials, semi-coke, etc.) from being carried into the connecting section 1-2 by the crude gas, thus avoiding coking and wall adhesion phenomena in the connecting section 1-2.

[0101] According to embodiments of this disclosure, the furnace of the gasifier 1 includes a turbulent fluidization section 1-1, a connecting section 1-2, and a conveying section 1-3. Along the gas flow direction, crude coal gas and hydrocarbon solid fuel enter the connecting section 1-2 through a connecting port located in the transition zone of the gasifier 1. A blind channel is provided in the connecting section 1-2 to enhance the mixing of the crude coal gas and hydrocarbon solid fuel; after mixing, the mixture is conveyed to the conveying section 1-3. Secondary air g4 is introduced into the conveying section 1-3 in a tangential manner to enhance the mixing of the secondary air g4 with the crude coal gas and hydrocarbon solid fuel and to carry out a gasification reaction, cracking the tar in the crude coal gas and simultaneously producing gasification products. Further, optionally, the gasification product is conveyed to a second gas-solid separator after the gasification reaction for gas-solid separation to obtain a first solid material A, pure syngas G, and fly ash H.

[0102] In the embodiments of this disclosure, the upper swirl conveying bed gasification reaction zone of the biomass dual-bed gasification device is constructed using connecting section 1-2 and conveying section 1-3. The apparent fluidization velocity of connecting section 1-2 is 8 m / s-20 m / s to ensure the smooth passage of crude gas and entrained solid particles within connecting section 1-2, preventing segregation and slagging at the bottom. The apparent fluidization velocity of conveying section 1-3 is 3 m / s-10 m / s to ensure sufficient reaction between the crude gas and secondary air g4, fully cracking the tar in the crude gas to produce pure syngas G and fly ash H. Secondary air g4 is introduced into conveying section 1-3 in a uniformly distributed tangential pattern, causing the downward-flowing solid material on the inner wall of conveying section 1-3 to swirl and fluidize towards the center. The flow velocity at the secondary air g4 nozzle is 30m / s-100m / s. By injecting the secondary air g4 into the fluidized gasification reaction zone of the transport section 1-3 at a higher velocity, the mixing, temperature diffusion and gasification reaction between the secondary air g4 and solid particles are enhanced. This avoids slagging and further reduces the tar content in the crude coal gas.

[0103] According to embodiments of this disclosure, by decoupling tar gasification and carbon gasification, the gasification of biomass materials achieves the characteristics of tar-free, low-slagging, and high conversion rates. To avoid slagging at the bottom of the turbulent fluidization section 1-1 and to achieve sufficient fluidization, the oxygen concentration of the primary air g3 entering the furnace of gasifier 1 is controlled at 15%-45%. To ensure sufficient tar cracking in the transport section 1-3, the oxygen concentration of the secondary air g4 is 21%-60%. In the biomass pyrolysis gasifier 4, to ensure sufficient cracking and gasification of biomass material B, the oxygen concentration of the first gasifying agent g1 is ≤21%; the oxygen concentration of the second gasifying agent g4 in the gasification reactor is 21%-100%, and the oxygen content in the second gasifying agent g2 accounts for 40%-80% of the total oxygen content of the gasifying agent in the biomass dual-bed gasification method, so as to ensure sufficient tar cracking in the pyrolysis gas PG.

[0104] According to embodiments of this disclosure, a first solid material A is returned to a biomass pyrolysis gasification furnace 4 via a first return feeder 3, mixing and preheating the biomass material B entering the biomass pyrolysis gasification furnace 4. The preheated biomass material B is then pyrolyzed and gasified by a first gasifying agent g1 entering the biomass pyrolysis gasification furnace 4, producing pyrolysis gas PG and a second solid material C. The second solid material C is returned to the gasification furnace 1 via the return leg of a second return feeder 5 for carbon gasification. Alternatively, the biomass pyrolysis gasification furnace 4 can be coupled with a second return feeder 5, wherein the second return feeder 5 is a U-shaped return feeder, including a descending section, a horizontal conveying section, and an ascending section. The second solid material C pyrolyzed in the biomass pyrolysis gasification furnace 4 is conveyed through the horizontal conveying pipe in the U-shaped return feeder to the ascending section of the U-shaped return feeder, and then returned to the gasification furnace 1 via the first return port 13 for carbon gasification.

[0105] According to an embodiment of this disclosure, when the gasification reactor is a gasification burner, the gasification reaction of the second gasifying agent g2 and the pyrolysis gasification gas PG includes: the pyrolysis gasification gas PG and the second gasifying agent g2 are injected into the dilute phase zone of the gasification furnace 1 through the gasification burner and the nozzle 14 at the top of the gasification furnace 1, mixed, and gasified to produce syngas and ash. The gasification burner includes a central channel and an annular channel surrounding the central channel. The pyrolysis gasification gas PG is introduced into the central channel, and the second gasifying agent g2 is introduced into the annular channel.

[0106] According to an embodiment of this disclosure, before the pyrolysis gasification gas PG enters the central channel of the gasification burner, the process further includes: passing the pyrolysis gasification gas PG into a second gas-solid separator for gas-solid separation; the separated pyrolysis gasification gas is then passed into the central channel of the gasification burner for subsequent gasification reaction; and the separated solid particles are returned to the dilute phase region of the turbulent fluidization section 1-1 through a return feeder for fluidization and gasification reaction.

[0107] According to embodiments of this disclosure, when the gasification reactor is a non-catalytic reactor equipped with a gasification burner, the gasification reaction is carried out within the non-catalytic reactor with the gasification burner, including: pyrolysis gasification gas PG and a second gasifying agent g2 entering the non-catalytic reactor 6 through the gasification burner for gasification reaction. The reaction temperature inside the non-catalytic reactor 6 is 950℃-1300℃, the residence time of the pyrolysis gasification gas PG and the second gasifying agent g2 is 2-6 s, and the velocity at the outlet 62 of the non-catalytic reactor is 5 m / s-15 m / s. By performing a high-temperature non-catalytic reforming reaction on the pyrolysis gasification gas PG in the non-catalytic reactor 6 and extending the reaction time, the tar in the pyrolysis gasification gas PG can be completely removed.

[0108] According to embodiments of this disclosure, when the gasification reactor is a gas-solid separator, a gasification reaction is carried out within the gas-solid separator gasifier, including: pyrolysis gas PG tangentially enters the gas-solid separator gasifier 7, and gas-solid separation occurs under the centrifugal force of the gas-solid separator gasifier 7; the separated pyrolysis gas PG is located in the central region of the gas-solid separator gasifier 7, and reacts with a second gasifying agent g2 introduced through the center of the gas-solid separator gasifier 7 to produce ash and syngas, while the separated solids swirl down along the inner wall to undergo carbon gasification. The apparent velocity of the pyrolysis gas PG tangentially entering the gas-solid separator gasifier 7 is 15 m / s-30 m / s, the apparent velocity of the second gasifying agent g2 entering the gas-solid separator gasifier 7 is 30 m / s-60 m / s, the equivalent interface velocity of the gas-solid separator gasifier 7 is 1.5 m / s-3 m / s, and the residence time of the pyrolysis gas PG and the second gasifying agent g2 is 2-5 s.

[0109] According to the embodiments of this disclosure, in the above embodiments, the non-catalytic reforming reaction temperature of pyrolysis gas PG and the second gasifying agent g2 is 1000℃-1300℃, and the temperature of the dense phase region at the bottom of the turbulent fluidization section 1-1 is 750-900℃. To avoid the ash and slag in the turbulent fluidization section 1-1 from agglomerating into large slag lumps and to avoid overheating of the top lining of the gasifier 1, the apparent velocity at the interface at the nozzle 14 at the top of the gasifier 1 is 5m / s-15m / s.

[0110] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A biomass dual-bed gasification device, characterized in that, include: A biomass pyrolysis gasification furnace is provided with a biomass feed inlet for biomass materials to enter, a first solid material inlet located downstream of the biomass feed inlet for receiving a first solid material, a first gasifying agent inlet located at the bottom of the furnace for introducing a first gasifying agent, a solid discharge outlet for discharging a second solid material, and a gas discharge outlet located at the top of the furnace for discharging pyrolysis gasification gas. The pyrolysis gasification gas and the second solid material are generated by the biomass materials after the first solid material preheats and mixes the biomass materials, and then the biomass materials are pyrolyzed and gasified with the first gasifying agent. The gasification reactor, located downstream of the biomass pyrolysis gasification furnace, is equipped with a pyrolysis gasification gas duct connected to the gas discharge outlet of the pyrolysis gasification gas, a second gasification agent duct for the second gasification agent to enter, and a gasification outlet for discharging the pyrolysis gasification gas and the second gasification agent or their gasification products. A gasifier is located downstream of the gasification reactor and connected to the gasification reactor via a nozzle located at the top of the gasifier. This allows the syngas and ash generated by the gasification reaction to come into contact with turbulent third solid material under the impetus of the gas. The sensible heat of the syngas and the ash provides the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel, and bottom ash. The third solid material includes bed material and the second solid material.

2. The biomass dual-bed gasification device according to claim 1, characterized in that, The furnace chamber of the gasifier includes a turbulent fluidization section, which includes, from bottom to top, a dense phase zone, a transition zone, and a dilute phase zone. The transition zone is provided with a first return port for the return of the second solid material. The nozzle is located at the top of the dilute phase zone, and the third solid material is turbulent in the dense phase zone. The bottom of the gasifier furnace is also provided with a slag discharge port for discharging the bottom ash, a primary air inlet, and an air distribution unit for supplying primary air into the gasifier furnace. The air distribution unit includes: an air cap, an air distribution panel, and an air chamber.

3. The biomass dual-bed gasification device according to claim 2, characterized in that, The gasifier is also equipped with: A connecting segment is connected to the transition area, and the transition area is also provided with a connection port connected to the connecting segment; The transport section is connected to the connecting section; Wherein, the included angle between the connection port and the first return port is 90°-180°, the height of the first return port from the air distribution plate is 0.5m-3m, and the height difference between the connection port and the first return port is 0.5m-3m; Preferably, it further includes: a section of tactile paving provided at the end of the connecting segment away from the connecting port; and The connection between the connecting section and the transport section extends along the gas direction, and a secondary air duct for secondary air to enter is provided in the transport section along the gas extension direction. Wherein, the length of the tactile paving is 0.2-1.25 times the diameter of the connecting section, and the angle between the axial direction and the horizontal direction of the secondary air duct is ±30° when the secondary air enters the transport section. There are multiple secondary air ducts, which are located on the same horizontal plane and arranged in a tangential circle around the transport section. The tangential diameter d of the secondary air duct is between 0.5 times the diameter of the connecting section and 0.80 times the diameter of the cross section where the center line of the secondary air duct nozzle is located.

4. The biomass dual-bed gasification device according to claim 3, characterized in that, Also includes: The first gas-solid separator is connected at one end to the outlet of the transport section; The other end is connected to the first return inlet of the first return feeder; The first return feeder is also provided with a first return outlet connected to the first solid material inlet of the biomass pyrolysis gasification furnace; The second return feeder is provided with a second return inlet connected to the solid discharge outlet of the second solid material of the biomass pyrolysis gasification furnace, and a second return outlet for returning the second solid material to the gasification furnace.

5. The biomass dual-bed gasification device according to any one of claims 1-4, characterized in that, The gasification reactor is a gasification burner, comprising: a central channel and an annular channel surrounding the central channel; the central channel is a pyrolysis gasification gas duct, the annular channel is a second gasifying agent duct, and the gasification outlet of the gasification burner is directly connected to the nozzle; or The gasification reactor is a non-catalytic reactor equipped with the gasification burner, wherein the gasification outlet of the gasification burner is connected to the inlet of the non-catalytic reactor, and the outlet of the non-catalytic reactor is connected to the nozzle; and Optionally, a further means is provided between the gasification burner and the biomass pyrolysis gasification furnace: Second gas-solid separator; The second gas-solid separator is provided with a second gasification product inlet, a second solid material outlet, and a second gaseous material outlet. The second gasification product inlet is connected to the gas discharge outlet for discharging the pyrolysis gasification gas, the second gas material outlet is connected to the central channel of the gasification burner, and the second solid material outlet is connected to the second return port provided in the dilute phase zone.

6. The biomass dual-bed gasification device according to claim 5, characterized in that, The gasification reactor is a gas-solid separation gasifier, which includes: The cylinder for gas-solid separation and gasification; The pyrolysis gasification gas duct is tangent to the cylinder body, and the second gasification agent duct is located on the central axis of the cylinder body.

7. The biomass dual-bed gasification device according to claim 6, characterized in that, The second return feeder is a U-shaped return feeder, comprising: a descending section, a horizontal conveying pipe, and an ascending section; The biomass pyrolysis gasifier is coupled to the descending section of the U-shaped return feeder, multiple sets of conveying air are arranged on the horizontal conveying pipe, and the ascending section is connected to the first return port of the gasifier.

8. A biomass dual-bed gasification method, characterized in that, include: After the biomass material is preheated and mixed by the first solid material entering the biomass pyrolysis gasification furnace, the biomass material undergoes a pyrolysis gasification reaction with the first gasifying agent entering the biomass pyrolysis gasification furnace to produce pyrolysis gasification gas and a second solid material. The second solid material is returned to the gasification furnace. The second gasifying agent and the pyrolysis gasification gas enter the turbulent fluidization section of the gasifier through the nozzles at the top of the gasifier reactor and the gasifier for gasification reaction, or they undergo gasification reaction in the gasifier reactor and then enter the turbulent fluidization section of the gasifier through the nozzles at the top of the gasifier, so as to crack the tar in the pyrolysis gasification gas through the gasification reaction to produce syngas and ash. The syngas and ash generated by the gasification reaction come into contact with turbulent third solid material under the impetus of the gas, and the sensible heat of the syngas and ash provides the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel and bottom ash, wherein the third solid material includes bed material and second solid material.

9. The biomass dual-bed gasification method according to claim 8, characterized in that, The gasification reactor is a gasification burner, wherein the second gasifying agent and the pyrolysis gas undergo a gasification reaction, including: The pyrolysis gas and the second gasifying agent are injected into the dilute phase zone of the gasifier through the gasification burner and the nozzle at the top of the gasifier, where they mix and undergo a gasification reaction; or The gasification reactor is a non-catalytic reactor equipped with the gasification burner, wherein the gasification reaction is carried out in the non-catalytic reactor equipped with the gasification burner, including: The pyrolysis gas and the second gasifying agent enter the non-catalytic reactor through a gasification burner to undergo a gasification reaction; and Optionally, the pyrolysis gasification gas further includes, before entering the central channel of the gasification burner: The pyrolysis gasification gas is introduced into the second gas-solid separator for gas-solid separation, and the separated pyrolysis gasification gas is then introduced into the central channel of the gasification burner. The gasification burner includes a central channel and an annular channel surrounding the central channel. Pyrolysis gas is introduced into the central channel, and the second gasification agent is introduced into the annular channel. The oxygen content in the second gasifying agent accounts for 40%-80% of the total oxygen content of the gasifying agent in the biomass dual-bed gasification method, the oxygen concentration in the second gasifying agent is 21%-100%, and the oxygen concentration in the first gasifying agent is less than or equal to 21%.

10. The biomass dual-bed gasification method according to claim 8, characterized in that, The gasification reactor is a gas-solid separation gasifier, wherein the gasification reaction takes place within the gas-solid separation gasifier, including: The pyrolysis gas enters the gas-solid separator tangentially, where gas-solid separation occurs under the centrifugal force of the gas-solid separator. The separated pyrolysis gas is located in the central region of the gas-solid separation gasifier and undergoes a gasification reaction with the second gasifying agent introduced through the center of the gas-solid separation gasifier.

11. The biomass dual-bed gasification method according to any one of claims 8-10, characterized in that, The process of utilizing the sensible heat of the syngas and the ash residue to provide the heat of reaction for the carbon gasification reaction, producing crude coal gas, hydrocarbon solid fuel, and bottom ash, includes: The syngas and the ash are brought into contact with and fully mixed with the third solid material in the dense phase zone of the gasifier. In the presence of primary air, the sensible heat of the syngas and the ash is used to provide the heat of reaction for the carbon gasification reaction, resulting in crude coal gas, hydrocarbon solid fuel and bottom ash. The oxygen concentration in the primary air is 15%-45%; The second solid material includes: pyrolyzed char, semi-coke, and bed material; The first solid material includes: semi-coke and bed material.

12. The biomass dual-bed gasification method according to claim 11, characterized in that, Along the gas flow direction, the crude coal gas and hydrocarbon solid fuel enter the connecting section through the connection port set in the transition zone of the gasifier, and a blind path set in the connecting section is used to enhance the mixing of the crude coal gas and hydrocarbon solid fuel; After mixing, the mixture is transported to the conveying section, where secondary air is introduced in a tangential manner to enhance the mixing of the secondary air with the crude coal gas and the hydrocarbon solid fuel and to carry out the gasification reaction, thereby cracking the tar in the crude coal gas and producing gasification products. as well as Also optionally including: After the gasification reaction, the gasification products are transported to the first gas-solid separator for gas-solid separation to obtain the first solid material, pure syngas and fly ash; The secondary air is introduced into the transport section in a tangential manner, the oxygen concentration in the secondary air is 21%-60%, and the flow velocity of the secondary air is 30m / s-100m / s; The first solid material enters the biomass pyrolysis gasification furnace via the first return feeder.

13. The biomass dual-bed gasification method according to claim 8, characterized in that, The second solid material is returned to the gasifier via the second return feeder; or The biomass pyrolysis gasifier is coupled to the second return feeder, which is a U-shaped return feeder. The second solid material pyrolyzed in the biomass pyrolysis gasifier is transported through the horizontal conveying pipe in the U-shaped return feeder to the rising section of the U-shaped return feeder and returned to the gasifier for carbon gasification reaction.

Images