A device and method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation

Abstract

A device and method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation belongs to the fields of chemical industry and power generation. A biomass circulating fluidized bed gasifier is connected to a high-efficiency cyclone separator 1, which is connected to a differential fluidized bed gasifier, which is connected to the biomass circulating fluidized bed gasifier. The high-efficiency cyclone separator 1 is connected to a large-scale coal-fired power generation boiler via a second superheater and a high-temperature gas blower. The differential fluidized bed gasifier is connected to a second high-efficiency cyclone separator, which is connected to the differential fluidized bed gasifier. The high-efficiency cyclone separator 2 is connected to an air preheater 3, a first superheater, a dust collector, a high-temperature steam shift reactor, a second air preheater, a low-temperature steam shift reactor, a first air preheater, a condenser, an organic amine scrubber, a compressor, a pressure swing adsorption system, and a large-scale coal-fired power generation boiler. This invention can achieve high-value utilization of biomass gasification hydrogen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical industry and power generation, and specifically relates to a device and method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation. Background Art

[0002] At present, coal and biomass coupled power generation basically uses circulating fluidized bed gasifiers as biomass gasification equipment. This technology has been mature in China, but the disposal of biomass charcoal produced by gasification has become a problem, resulting in the technology being not economical and difficult to promote and apply on a large scale. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem that biomass charcoal produced by biomass coupled with coal-fired power generation is difficult to apply, and to provide a device and method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation.

[0004] The present invention utilizes the inherent conditions of a circulating fluidized bed gasifier to gasify biomass char with water vapor to produce hydrogen, thereby achieving high-value utilization of the biomass char.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] Solution 1: A biomass gasification coupled with large-scale coal-fired power generation and H2 co-production device, comprising a first screw feeder, a second screw feeder, a biomass circulating fluidized bed gasifier, a differential fluidized bed gasifier, a first high-efficiency cyclone separator, a second high-efficiency cyclone separator, a first superheater, a second superheater, a first air preheater, a second air preheater, a third air preheater, a high-temperature gas blower, a dust collector, a condenser, a large-scale coal-fired power generation boiler, a high-temperature water-steam shift reactor, a low-temperature water-steam shift reactor, an organic amine scrubber, a compressor, and a pressure swing adsorption system;

[0007] A biomass feeding port is provided on the top of the screw feeder 1, and a circulating material feeding port is provided on the top of the screw feeder 2. The discharge ports of the screw feeder 1 and the screw feeder 2 are respectively connected with the corresponding feed ports of the biomass circulating fluidized bed gasifier, and the gas outlet at the top of the biomass circulating fluidized bed gasifier is connected with the gas inlet of the high-efficiency cyclone separator 1, and the discharge port at the lower end of the high-efficiency cyclone separator is connected with the feed port 1 of the differential fluidized bed gasifier through a return valve 1, and the discharge port of the differential fluidized bed gasifier is connected with the return inlet of the biomass circulating fluidized bed gasifier through a return valve 2; the gas outlet at the top of the high-efficiency cyclone separator 1 is connected with the gas inlet of the superheater 2, and the gas outlet of the superheater 2 is connected to the large The gas inlet of the coal-fired power generation boiler is connected; the synthesis gas outlet at the top of the differential fluidized bed gasifier is connected to the synthesis gas inlet of the high-efficiency cyclone separator No. 2, and the discharge port at the lower end of the high-efficiency cyclone separator No. 2 is connected to the feed port No. 2 of the differential fluidized bed gasifier; the synthesis gas outlet at the top of the high-efficiency cyclone separator No. 2 is connected to the synthesis gas inlets of the air preheater No. 3 and the superheater No. 1 in sequence, the synthesis gas outlet of the superheater No. 1 is connected to the inlet of the dust collector, and the outlet of the dust collector is connected to the high-temperature water vapor shift reactor, the air preheater No. 2, the low-temperature water vapor shift reactor, the air preheater No. 1, the condenser, the organic amine scrubber, the compressor and the pressure swing adsorption system in sequence, and the exhaust port of the pressure swing adsorption system is connected to the furnace of the large coal-fired power generation boiler through a pipeline.

[0008] Furthermore, the steam outlet of the large coal-fired power generation boiler is connected to the steam inlet of the steam turbine generator set through a pipeline, and the low-pressure cylinder steam extraction outlet of the steam turbine generator set is connected to the bottom wind chamber of the differential fluidized bed gasifier through superheater 1 and superheater 2 in turn.

[0009] Furthermore, the outlet of the blower is connected to the air inlet of air preheater one, the air outlet of air preheater one is connected to the air inlet of air preheater two, the air outlet of air preheater two is connected to the air inlet of air preheater three, and the high-temperature air outlet of air preheater three is connected to the bottom wind chamber of the biomass circulating fluidized bed gasifier.

[0010] A method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation, the method comprising the following steps:

[0011] Step 1: High-temperature air at 650-700°C is introduced into the wind chamber at the bottom of the biomass circulating fluidized bed gasifier; at the same time, biomass and circulating materials are respectively fed into the biomass circulating fluidized bed gasifier through screw feeder 1 and screw feeder 2, where the biomass is gasified and pyrolyzed, and the circulating materials are calcined and decomposed into CaO and MgO; the 900-950°C high-temperature gas discharged from the gas outlet at the upper end of the biomass circulating fluidized bed gasifier enters the high-efficiency cyclone separator 1, where the circulating materials and biochar carried in the high-temperature gas are separated, and then steam-activated through the return valve 1 and fed into the differential fluidized bed gasifier, where the activated biochar reacts with 700-750°C high-temperature steam to generate synthesis gas;

[0012] Step 2: The 900-950°C high-temperature gas discharged from the gas outlet at the top of the high-efficiency cyclone separator 1 enters the superheater 2, where the gas temperature is reduced to 450°C. Afterwards, it is sent to the large coal-fired power generation boiler through the high-temperature gas fan for combustion and power generation;

[0013] Step 3: The high-temperature and high-pressure steam generated by the large-scale coal-fired power generation boiler is sent to the steam turbine generator set to generate electricity. The steam enters the superheater 1 from the steam outlet of the steam turbine generator set and is heated to 380°C. It then enters the superheater 2 and is heated to 700-750°C. The 700-750°C superheated steam then enters the differential fluidized bed gasifier from the bottom wind chamber of the differential fluidized bed gasifier. The mass ratio of steam to biochar is 1-3:1. Biochar is the product of biomass gasification and accounts for 25-30% of the biomass feed. The flue gas generated by the large-scale coal-fired power generation boiler enters the chimney through the flue gas fan and is discharged into the atmosphere.

[0014] Step 4: In the differential fluidized bed gasifier, the high-temperature circulating material and high-temperature superheated steam heat the differential fluidized bed gasifier to 780-900°C. The biochar reacts with the high-temperature steam at this temperature to generate synthesis gas. The synthesis gas is composed of H2, CO, CO2, CH4 and H2S, of which: H2 accounts for 75%-77% by volume, CO accounts for 7-8% by volume, CO2 accounts for 6.5-8.5% by volume, CH4 accounts for 6.5-8% by volume, and the original H2S is <100mg / Nm 3 , biochar gas production rate 2.5-3.6Nm 3 / kg; At the same time, the CaO and MgO formed after the calcination of limestone and dolomite react with H2S to remove 90% of H2S, and H2S <10mg / Nm 3 ;

[0015] Step 5: The high-temperature synthesis gas coming out of the top of the differential fluidized bed gasifier first enters the high-efficiency cyclone separator 2 to separate the unreacted biomass char and bed material carried by the synthesis gas and send them to the differential fluidized bed gasifier for circulation gasification; the synthesis gas coming out of the top of the high-efficiency cyclone separator 2 passes through the air preheater 3 and the superheater 1 in turn and is cooled to 350℃, and then enters the dust collector for dust removal. The dust-removed synthesis gas enters the high-temperature water steam shift reactor, and then passes through the air preheater 2 to cool to 190-200℃ , then enters the low-temperature water gas shift reactor, and after the temperature rises to 250-260℃, it enters the air preheater 1, preheating the air from room temperature to 130-150℃, and the synthesis gas temperature drops to 120-150℃. Then it enters the condenser and organic amine scrubber in sequence to remove CO2 and impurities in the synthesis gas, and finally enters the pressure swing adsorption system through the compressor to obtain 99.9% H2. The gas discharged from the pressure swing adsorption system is sent to a large coal-fired power generation boiler through a pipeline for combustion, and the released heat is used for power generation.

[0016] Option 2: A biomass gasification coupled with large-scale coal-fired power generation and H2 co-production device, comprising a first screw feeder, a second screw feeder, a biomass circulating fluidized bed gasifier, a differential fluidized bed gasifier, a fluidized bed calciner, a first high-efficiency cyclone separator, a second high-efficiency cyclone separator, a first superheater, a second superheater, a first air preheater, a second air preheater, a third air preheater, a high-temperature gas blower, a dust collector, a condenser, a large-scale coal-fired power generation boiler, a high-temperature water-steam shift reactor, a low-temperature water-steam shift reactor, an organic amine scrubber, a compressor, and a pressure swing adsorption system;

[0017] A biomass feeding port is provided on the top of the screw feeder 1, and a circulating material feeding port is provided on the top of the screw feeder 2. The discharge ports of the screw feeder 1 and the screw feeder 2 are respectively connected with the corresponding feed ports of the biomass circulating fluidized bed gasifier, the gas outlet at the top of the biomass circulating fluidized bed gasifier is connected with the gas inlet of the high-efficiency cyclone separator 1, the discharge port at the lower end of the high-efficiency cyclone separator is connected with the feed port 1 of the differential fluidized bed gasifier through the return valve 1, the discharge port of the differential fluidized bed gasifier is connected with the feed port of the fluidized bed calcining bed through the return valve 2, the discharge port of the fluidized bed calcining bed is connected with the return inlet of the biomass circulating fluidized bed gasifier; the gas outlet at the top of the high-efficiency cyclone separator 1 is connected with the gas inlet of the superheater 2, and the gas outlet of the superheater 2 is connected with the gas inlet of the superheater 2. The outlet is connected to the gas inlet of a large coal-fired power generation boiler through a high-temperature gas blower; the synthesis gas outlet at the top of the differential fluidized bed gasifier is connected to the synthesis gas inlet of the high-efficiency cyclone separator No. 2, and the discharge port at the lower end of the high-efficiency cyclone separator No. 2 is connected to the feed port No. 2 of the differential fluidized bed gasifier; the synthesis gas outlet at the top of the high-efficiency cyclone separator No. 2 is connected to the synthesis gas inlets of the air preheater No. 3 and the superheater No. 1 in sequence, the synthesis gas outlet of the superheater No. 1 is connected to the inlet of the dust collector, the outlet of the dust collector is connected to the high-temperature water vapor shift reactor, the air preheater No. 2, the low-temperature water vapor shift reactor, the air preheater No. 1, the condenser, the organic amine scrubber, the compressor and the pressure swing adsorption system in sequence, and the exhaust port of the pressure swing adsorption system is connected to the furnace of the large coal-fired power generation boiler through a pipeline.

[0018] Furthermore, the steam outlet of the large coal-fired power generation boiler is connected to the steam inlet of the steam turbine generator set through a pipeline, and the low-pressure cylinder steam extraction outlet of the steam turbine generator set is connected to the bottom wind chamber of the differential fluidized bed gasifier through superheater 1 and superheater 2 in turn.

[0019] Furthermore, the outlet of the blower is connected to the air inlet of air preheater one, the air outlet of air preheater one is connected to the air inlet of air preheater two, the air outlet of air preheater two is connected to the air inlet of air preheater three, and the high-temperature air outlet of air preheater three is connected to the bottom wind chamber of the biomass circulating fluidized bed gasifier.

[0020] A method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation, the method comprising the following steps:

[0021] Step 1: 350-400°C medium-temperature air is introduced into the bottom air chamber of the biomass circulating fluidized bed gasifier; at the same time, biomass and circulating materials are fed into the biomass circulating fluidized bed gasifier through screw feeder 1 and screw feeder 2, where the biomass is gasified and pyrolyzed. The circulating materials consist of limestone, dolomite, and Ni catalyst; 750-850°C high-temperature gas discharged from the gas outlet of the biomass circulating fluidized bed gasifier carries biochar and circulating materials into high-efficiency cyclone separator 1, where the circulating materials and biochar carried in the high-temperature gas are separated and then fed into the differential fluidized bed gasifier after steam activation through return valve 1;

[0022] Step 2: The high-temperature gas discharged from the gas outlet at the top of the high-efficiency cyclone separator 1 enters the superheater 2, where the gas temperature is reduced to 450°C. After that, it is sent to the large coal-fired power generation boiler through the high-temperature gas fan for combustion and power generation;

[0023] Step 3: The high-temperature and high-pressure steam generated by the large coal-fired power generation boiler is sent to the steam turbine generator set through a pipeline to generate electricity. The steam from the steam turbine generator set enters superheater 1 and is heated to 380°C. It then enters superheater 2 and is heated to 550-600°C superheated steam. The 550-600°C superheated steam then enters the differential fluidized bed gasifier through the bottom wind chamber of the differential fluidized bed gasifier.

[0024] Step 4: In the differential fluidized bed gasifier, high-temperature circulating materials and high-temperature superheated steam heat the differential fluidized bed gasifier to 600-700°C, absorb CO2 in situ, and react with high-temperature steam under the action of the calcined products of limestone and dolomite and the Ni-based catalyst to generate synthesis gas H2, CO, CO2, CH4 and H2S. At the same time, CaO and CO2 undergo an in-situ absorption reaction to generate CaCO3, which promotes the reaction of CO+H2O=H2+CO2 in the positive direction. CaO reacts with H2S to generate CaS. The circulating materials containing CaCO3 and CaS and the unreacted biomass charcoal enter the fluidized bed calcining bed through the second return valve. Air is introduced into the fluidized bed calcining bed, and part of the charcoal burns to heat the bed temperature to 850-900°C, so that CaCO3 is decomposed into CaO and CO2, and CaS is decomposed into CaO and SO2. The Ni-based catalyst eliminates carbon deposits and then enters the biomass circulating fluidized bed gasifier;

[0025] Step 5: The high-temperature synthesis gas coming out of the top of the differential fluidized bed gasifier first enters the high-efficiency cyclone separator 2 to separate the unreacted biomass charcoal and circulating materials carried by the synthesis gas and send them to the differential fluidized bed gasifier for circulation gasification; the high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 passes through the air preheater 3 and the superheater 1 in sequence and is cooled to 350°C, and then enters the dust collector for dust removal, and then the synthesis gas enters the high-temperature water steam shift reactor, and the synthesis gas with a temperature rise of 380-450°C enters the air preheater 2, and the synthesis gas temperature is reduced to 1 90-200℃ and enters the low-temperature water gas shift reactor, the synthesis gas is heated to 250-260℃, and then enters the air preheater 1, preheating the air from room temperature to 130-150℃, and the synthesis gas temperature drops to 120-150℃. The synthesis gas then enters the condenser and organic amine scrubber, and the synthesis gas temperature drops to 50-60℃. The synthesis gas then enters the pressure swing adsorption system through the compressor to obtain 99.9% H2. The gas discharged from the pressure swing adsorption system is sent to a large coal-fired power generation boiler through a pipeline for combustion, and the released heat is used for power generation.

[0026] Furthermore, the mass ratio of limestone, dolomite and Ni-based catalyst is 1:1:1.

[0027] Furthermore, the synthesis gas enters the organic amine scrubber to remove the remaining dust, trace H2S and more than 90% of CO2 in the synthesis gas. The organic amine aqueous solution absorbs CO2 and is regenerated and heated to 120-150°C. Then, CO2 and water vapor are decomposed and separated after condensation to obtain high-purity CO2.

[0028] The beneficial effects of the present invention relative to the prior art are:

[0029] The present invention solves the problem that biochar in the prior art is difficult to promote and apply, and converts biochar into H2, greatly improving the economic efficiency of the unit operation. The biomass power generation efficiency of the present invention reaches 40%, which is much higher than the current biomass direct combustion power generation efficiency and has significant advancedness. Compared with the existing biomass gasification hydrogen production, the present invention uses biochar produced by biomass gasification as raw material, avoiding the problem of a large amount of tar produced in the original biomass gasification process, and solving the problem of tar contamination of heat exchange equipment. In addition, using biochar as a gasification hydrogen production raw material, the volume share of H2 in the synthesis gas accounts for 75-77%. After water vapor conversion in the high-temperature water vapor conversion reactor (WGS-1) and the low-temperature water vapor conversion reactor (WGS-2), the volume share of H2 is more than 85%. After CO2 is absorbed by organic amines, the volume share of H2 is more than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of a biomass gasification coupled with large-scale coal-fired power generation device for H2 co-production. Figure 1, Differential fluidized bed gasifier 3 bed temperature: 780-900℃;

[0031] Figure 2 This is a schematic diagram of the structure of a biomass gasification coupled with large-scale coal-fired power generation device for H2 co-production. Figure 2 , Differential fluidized bed gasification furnace bed temperature: 600-700℃, in-situ absorption of CO2;

[0032] Figure 3 yes Figure 1 The enlarged view of the part at point A is the enlarged view after rotating 90° clockwise;

[0033] Figure 4 yes Figure 1 A partial enlarged view of point B;

[0034] Figure 5 yes Figure 2 The partial enlarged view of point C is the partial enlarged view after rotating 90° clockwise;

[0035] Figure 6 yes Figure 2 A partial enlarged view of point D.

[0036] The names of the components and their corresponding reference numerals in the above drawings are as follows:

[0037] Screw feeder 1-1, screw feeder 2 1-2, biomass circulating fluidized bed gasifier 2, differential fluidized bed gasifier 3, high-efficiency cyclone separator 1 4, high-efficiency cyclone separator 2 5, return valve 1 6, return valve 2 7, superheater 1 8, superheater 2 9, air preheater 1 10, air preheater 2 11, air preheater 3 12, high-temperature gas blower 13, dust collector 14, condenser 15, large coal-fired power generation boiler 16, high-temperature water steam shift reactor 17, low-temperature water steam shift reactor 18, organic amine scrubber 19, compressor 20, pressure swing adsorption system 21, fluidized bed calcining bed 22, flue gas fan 23, chimney 24, steam turbine generator set 25, blower 26, biomass feed port 27, circulating material feed port 28, ash bin 29. DETAILED DESCRIPTION

[0038] Specific implementation method 1: Figure 1 、 Figure 3 and Figure 4As shown, this embodiment discloses a device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation (differential fluidized bed gasifier 3 bed temperature: 780-900°C), including a screw feeder 1-1, a screw feeder 2 1-2, a biomass circulating fluidized bed gasifier 2, a differential fluidized bed gasifier 3, a high-efficiency cyclone separator 4, a high-efficiency cyclone separator 2 5, a return valve 1 6, a return valve 2 7, a superheater 1 8, a superheater 2 9, an air preheater 1 10, an air preheater 2 11, an air preheater 3 12, a high-temperature gas blower 13, a dust collector 14, a condenser 15, a large-scale coal-fired power generation boiler 16, a high-temperature water steam shift reactor 17, a low-temperature water steam shift reactor 18, an organic amine scrubber 19, a compressor 20, a pressure swing adsorption system 21, a flue gas blower 23 and an ash bin 29;

[0039] A biomass feeding port 27 is provided at the top of the screw feeder 1-1, and a circulating material feeding port 28 is provided at the top of the screw feeder 1-2. The discharge ports of the screw feeder 1-1 and the screw feeder 2 1-2 are respectively connected to the corresponding feed ports of the biomass circulating fluidized bed gasifier 2. The gas outlet at the top of the biomass circulating fluidized bed gasifier 2 is connected to the gas inlet of the high-efficiency cyclone separator 4. The discharge port at the lower end of the high-efficiency cyclone separator 4 is connected to the feed port 1 of the differential fluidized bed gasifier 3 through a return valve 6. The discharge port of the differential fluidized bed gasifier 3 is connected to the return inlet of the biomass circulating fluidized bed gasifier 2 through a return valve 2 7.

[0040] The gas outlet at the top of the high-efficiency cyclone separator 4 is connected to the gas inlet of the superheater 9. The gas outlet of the superheater 9 is connected to the gas inlet of the large coal-fired power generation boiler 16 through the high-temperature gas fan 13. The flue gas outlet of the large coal-fired power generation boiler 16 is connected to the chimney 24 through the flue gas fan 23.

[0041] The syngas outlet at the top of the differential fluidized bed gasifier 3 is connected to the syngas inlet of the high-efficiency cyclone separator 2 5, and the discharge port at the lower end of the high-efficiency cyclone separator 2 5 is connected to the feed port 2 of the differential fluidized bed gasifier 3;

[0042] The synthesis gas outlet at the top of the high-efficiency cyclone separator 2 5 is connected to the synthesis gas inlets of the air preheater 3 12 and the superheater 1 8 in sequence, the synthesis gas outlet of the superheater 8 is connected to the inlet of the dust collector 14, the outlet of the dust collector 14 is connected to the high-temperature water vapor shift reactor 17, the air preheater 2 11, the low-temperature water vapor shift reactor 18, the air preheater 10, the condenser 15, the organic amine scrubber 19, the compressor 20 and the pressure swing adsorption system 21 in sequence, the exhaust port of the pressure swing adsorption system 21 is connected to the furnace of the large coal-fired power generation boiler 16 through a pipeline; the dust exhaust port at the bottom of the dust collector 14 is connected to the ash bin 29.

[0043] The steam outlet of the large coal-fired power generation boiler 16 is connected to the steam inlet of the steam turbine generator set 25 through a pipeline. The low-pressure cylinder steam extraction outlet of the steam turbine generator set 25 is connected to the bottom wind chamber of the differential fluidized bed gasifier 3 through superheater 1 8 and superheater 2 9 in sequence.

[0044] The outlet of the blower 26 is connected to the air inlet of the air preheater 10, the air outlet of the air preheater 10 is connected to the air inlet of the air preheater 2 11, the air outlet of the air preheater 2 11 is connected to the air inlet of the air preheater 3 12, and the high-temperature air outlet of the air preheater 3 12 is connected to the bottom air chamber of the biomass circulating fluidized bed gasifier 2.

[0045] Specific implementation method 2: Figure 1 、 Figure 3 and Figure 4 As shown, this embodiment discloses a method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation (differential fluidized bed gasifier 3 bed temperature: 780-900°C): the method is implemented based on the device described in the specific embodiment 1; the method includes the following steps:

[0046] Step 1: High-temperature air (650-700°C) enters the biomass circulating fluidized bed gasifier 2 from the bottom air chamber of the biomass circulating fluidized bed gasifier 2. The biomass circulating fluidized bed gasifier 2 is an adiabatic furnace with a fluidization velocity of 6-10m / s, a circulation ratio of 30-100, and an air equivalent coefficient α=0.15-0.25. Biomass (added in an amount of 10-50t / h, the biomass is straw briquette fuel, rice husk or wood briquette fuel) and recycled material (the recycled material consists of limestone and dolomite, and the mass ratio of limestone to dolomite is 1:1) are respectively fed into the biomass circulating fluidized bed gasifier 2 through screw feeder 1-1 and screw feeder 2 1-2. Biomass is gasified and pyrolyzed here, and the recycled materials are calcined and decomposed into CaO and MgO here; the high-temperature fuel gas (900-950°C) discharged from the fuel gas outlet at the upper end of the biomass circulating fluidized bed gasifier 2 carries biochar and recycled materials (limestone and dolomite calcined products) into the high-efficiency cyclone separator-4, and the recycled materials and biochar carried in the high-temperature fuel gas are separated by the high-efficiency cyclone separator-4, and then steam-activated through the return valve-6 and sent to the differential fluidized bed gasifier 3. The activated biochar reacts with 700-750°C high-temperature steam in the differential fluidized bed gasifier 3 to generate synthesis gas (the generated synthesis gas contains H2, CO, CO2, and CH4);

[0047] Step 2: The 900-950°C high-temperature gas discharged from the gas outlet at the top of the high-efficiency cyclone separator 4 enters the superheater 2 9, which heats the steam temperature from 380°C to 700-750°C and reduces the gas temperature to 450°C. The gas is then fed into the large coal-fired power generation boiler 16 via the high-temperature gas blower 13 to generate electricity, achieving a power generation efficiency of over 40%.

[0048] Step 3: The high-temperature and high-pressure steam generated by the large coal-fired power generation boiler 16 is sent to the steam turbine generator set 25 to generate electricity (power: 300-1000MW). 0.2-0.3MPa steam with a temperature of 200-250℃ is extracted from the low-pressure cylinder of the steam turbine generator set 25 and enters the superheater 8 to be heated to 380℃ (heating to 380℃ can prevent the surface of the superheater 9 from being contaminated with tar, because the wall temperature of the superheater 9 will be greater than 400℃, and the large molecular tar in the fuel gas is in gaseous state). Then it enters the superheater 8. The second heat exchanger 9 heats the gas to 700-750°C, after which superheated steam at 700-750°C enters the differential fluidized bed gasifier 3 from the bottom wind chamber of the differential fluidized bed gasifier 3. The mass ratio of steam to biochar is 1-3:1. The biochar is a product of biomass gasification and is 25-30% of the biomass feed (wooden biochar is 25% of wood briquette fuel and 30% of agricultural straw). The flue gas generated by the large coal-fired power generation boiler 16 enters the chimney 24 through the flue gas fan 23 and is discharged into the atmosphere.

[0049] Step 4: In the differential fluidized bed gasifier 3, the high-temperature circulating material and high-temperature superheated steam heat the differential fluidized bed gasifier 3 to 780-900°C. The biochar reacts with the high-temperature steam at this temperature to generate synthesis gas. The synthesis gas consists of H2, CO, CO2, CH4 and H2S, of which: H2 accounts for 75%-77% by volume, CO accounts for 7-8% by volume, CO2 accounts for 6.5-8.5% by volume, CH4 accounts for 6.5-8% by volume, and the original H2S is <100mg / Nm 3 , biochar gas production rate 2.5-3.6Nm 3 / kg; At the same time, the CaO and MgO formed after the calcination of limestone and dolomite react with H2S (the reaction time in the differential fluidized bed gasifier 3 is not less than 10s), removing 90% of H2S, H2S <10mg / Nm 3 (To meet the need for subsequent water gas shift reaction catalyst to not fail);

[0050] Step 5: The high-temperature synthesis gas coming out of the top of the differential fluidized bed steam gasifier 3 first enters the high-efficiency cyclone separator 2 5 to separate the unreacted biomass char and bed material carried by the synthesis gas and send them to the differential fluidized bed gasifier 3 for circulation gasification (to improve gasification efficiency). The high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 5 passes through the air preheater 3 12 and the superheater 1 8 in turn for heat exchange and is cooled to 350°C. It then enters the dust collector 14 (the dust collector 14 can be an existing mature ceramic filter tube dust collector 14 or a metal filter bag dust collector 14, or other dust collectors 14 that can withstand temperatures above 350°C) for dust removal. The dust removal efficiency reaches more than 99.9%, and the dust content in the synthesis gas is ≤5mg / m 3 The syngas after dust removal enters the high-temperature water-gas shift reactor 17 (WGS-1), and the syngas with a temperature of 380-450°C enters the air preheater 11 to preheat the air to 250-300°C, and the syngas temperature drops to 190-200°C, and then enters the low-temperature water-gas shift reactor 18 (WGS-2). After the syngas is heated to 250-260°C, it enters the air preheater 10 to preheat the air from room temperature to 130-150°C, and the syngas temperature drops to 120-150°C, and then the syngas enters the condenser 15 (existing mature technology); a part of the feed water of the large coal-fired power generation boiler 16 is used to condense the water vapor in the syngas through the condenser 15 for heat exchange, and the steam is recovered. The latent heat of gasification is reduced, thereby improving the thermal efficiency of the system; the synthesis gas then enters the organic amine scrubber 19 (mature technology) to remove dust, trace H2S and more than 90% of CO2 in the synthesis gas, and the synthesis gas temperature drops to 50-60°C. The organic amine aqueous solution absorbs CO2 and then regenerates (heated to 120-150°C, and then CO2 and water vapor are decomposed, and high-purity CO2 is separated after condensation), thereby achieving CO2 capture; the synthesis gas then enters the pressure swing adsorption system 21 (PSA) after passing through the compressor 20 to obtain 99.9% H2. The gas discharged from the pressure swing adsorption system 21 (PSA) (containing H2, CO, CO2, etc.) is sent to the large coal-fired power generation boiler 16 through a pipeline for combustion, and the released heat is used for power generation.

[0051] The effect of the second embodiment is as follows: the biomass char produced by the biomass circulating fluidized bed gasifier 2 enters the differential fluidized bed gasifier 3 to produce hydrogen-rich synthesis gas, with H2 accounting for 75%-77% by volume, CO accounting for 7-8% by volume, CO2 accounting for 6.5-8.5% by volume, and CH4 accounting for 6.5-8% by volume. The biochar gas production rate is 2.5-3.6Nm 3 / kg; 99.9% H2 is obtained through a high-temperature water vapor shift reactor 17, a low-temperature water vapor shift reactor 18, an organic amine scrubber 19 and a pressure swing adsorption system 21; at the same time, the combustible gas produced by the biomass circulating fluidized bed gasifier 2 is sent to a large coal-fired power generation boiler 16 for combustion and power generation.

[0052] Specific implementation method three: Figure 2 、 Figure 5 and Figure 6 As shown, this embodiment discloses a device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation (differential fluidized bed gasifier 3 bed temperature: 600-700°C, CO2 in-situ absorption), including a screw feeder 1-1, a screw feeder 2 1-2, a biomass circulating fluidized bed gasifier 2, a differential fluidized bed gasifier 3, a fluidized bed calcining bed 22, a high-efficiency cyclone separator 4, a high-efficiency cyclone separator 2 5, a return valve 1 6, a return valve 2 7, a superheater 1 8, a superheater 2 9, an air preheater 1 10, an air preheater 2 11, an air preheater 3 12, a high-temperature gas blower 13, a dust collector 14, a condenser 15, a large-scale coal-fired power generation boiler 16, a high-temperature water steam shift reactor 17, a low-temperature water steam shift reactor 18, an organic amine scrubber 19, a compressor 20, a pressure swing adsorption system 21, a flue gas blower 23 and an ash bin 29;

[0053] A biomass feeding port 27 is provided at the top of the screw feeder 1-1, and a circulating material feeding port 28 is provided at the top of the screw feeder 1-2. The discharge ports of the screw feeder 1-1 and the screw feeder 2 1-2 are respectively connected to the corresponding feed ports of the biomass circulating fluidized bed gasifier 2. The gas outlet at the top of the biomass circulating fluidized bed gasifier 2 is connected to the gas inlet of the high-efficiency cyclone separator 4. The discharge port at the lower end of the high-efficiency cyclone separator 4 is connected to the feed port 1 of the differential fluidized bed gasifier 3 through a return valve 6. The discharge port of the differential fluidized bed gasifier 3 is connected to the feed port of the fluidized bed calcining bed 22 through a return valve 27. The discharge port of the fluidized bed calcining bed 22 is connected to the return inlet of the biomass circulating fluidized bed gasifier 2.

[0054] The gas outlet at the top of the high-efficiency cyclone separator 4 is connected to the gas inlet of the superheater 9. The gas outlet of the superheater 9 is connected to the gas inlet of the large coal-fired power generation boiler 16 through the high-temperature gas fan 13. The flue gas outlet of the large coal-fired power generation boiler 16 is connected to the chimney 24 through the flue gas fan 23.

[0055] The syngas outlet at the top of the differential fluidized bed gasifier 3 is connected to the syngas inlet of the high-efficiency cyclone separator 2 5, and the discharge port at the lower end of the high-efficiency cyclone separator 2 5 is connected to the feed port 2 of the differential fluidized bed gasifier 3;

[0056] The syngas outlet at the top of the high-efficiency cyclone separator 2 5 is connected in sequence to the syngas inlets of the air preheater 3 12 and the superheater 1 8 . The syngas outlet of the superheater 8 is connected in sequence to the inlet of the dust collector 14 . The outlet of the dust collector 14 is connected in sequence to the high-temperature water steam shift reactor 17 , the air preheater 2 11 , the low-temperature water steam shift reactor 18 , the air preheater 10 , the condenser 15 , the organic amine scrubber 19 , the compressor 20 , and the pressure swing adsorption system 21 . The exhaust port of the pressure swing adsorption system 21 is connected to the furnace of the large coal-fired power generation boiler 16 via a pipeline. The dust outlet at the bottom of the dust collector 14 is connected to the ash bin 29 .

[0057] The steam outlet of the large coal-fired power generation boiler 16 is connected to the steam inlet of the steam turbine generator set 25 through a pipeline. The low-pressure cylinder steam extraction outlet of the steam turbine generator set 25 is connected to the bottom wind chamber of the differential fluidized bed gasifier 3 through superheater 1 8 and superheater 2 9 in sequence;

[0058] The outlet of the blower 26 is connected to the air inlet of the air preheater 10, the air outlet of the air preheater 10 is connected to the air inlet of the air preheater 2 11, the air outlet of the air preheater 2 11 is connected to the air inlet of the air preheater 3 12, and the high-temperature air outlet of the air preheater 3 12 is connected to the bottom air chamber of the biomass circulating fluidized bed gasifier 2.

[0059] Specific implementation method four: Figure 2 、 Figure 5 and Figure 6 As shown (differential bed low temperature), this embodiment discloses a method for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation (differential fluidized bed gasifier 3 bed temperature: 600-700°C, in-situ absorption of CO2): the method described in this embodiment is implemented with the aid of the device described in the specific embodiment 3; the method comprises the following steps:

[0060] Step 1: Medium-temperature air (350-400°C) enters the biomass circulating fluidized bed gasifier 2 from the bottom air chamber of the biomass circulating fluidized bed gasifier 2. The biomass circulating fluidized bed gasifier 2 is an adiabatic furnace with a fluidization velocity of 5-6m / s, a circulation ratio of 20-30, and an air equivalent coefficient α of 0.20-0.30. At the same time, the biomass and the circulating material (the circulating material is composed of limestone, dolomite and Ni catalyst, the mass ratio of limestone to dolomite and Ni catalyst is 1:1:1, the amount of biomass added is 10-50t / h, and the biomass is straw molded fuel, rice husk or wood molded fuel) are respectively fed through a screw feeder 1-1 and a screw feeder 2-2. Feeder 2 1-2 feeds the biomass into the biomass circulating fluidized bed gasifier 2, where the biomass is gasified and pyrolyzed. The gas outlet temperature of the upper end of the biomass circulating fluidized bed gasifier 2 is 750-850°C. The 750-850°C high-temperature gas discharged from the gas outlet of the biomass circulating fluidized bed gasifier 2 carries the biochar and recycled materials (limestone, dolomite and Ni catalyst) into the high-efficiency cyclone separator 4. The recycled materials and biochar carried in the high-temperature gas are separated by the high-efficiency cyclone separator 4, and then steam-activated through the return valve 6 before being fed into the differential fluidized bed steam gasifier 3. The purpose of steam activation is to increase the hydrogen production activity of the biochar.

[0061] Step 2: The high-temperature gas discharged from the gas outlet at the top of the high-efficiency cyclone separator 4 enters the superheater 2 9, which heats the steam temperature from 380°C to 550-600°C and reduces the gas temperature to 450°C. The gas is then fed by the high-temperature gas blower 13 into the large-scale coal-fired power generation boiler 16 for combustion and power generation, achieving a power generation efficiency exceeding 40%. The flue gas generated by the combustion in the large-scale coal-fired power generation boiler 16 enters the chimney 24 through the flue gas blower 23 and is discharged into the atmosphere.

[0062] Step 3: The high-temperature, high-pressure steam generated by the large-scale coal-fired power generation boiler 16 is fed through a pipeline to the steam turbine generator set 25 to generate electricity (power: 300-1000MW). The low-pressure cylinder of the steam turbine generator set 25 extracts 0.2-0.3MPa steam at a temperature of 200-250°C, enters the superheater 8 and is heated to 380°C. Then, it enters the superheater 9 and is heated to 550-600°C superheated steam. The 550-600°C superheated steam then enters the differential fluidized bed gasifier 3 through the bottom wind chamber of the differential fluidized bed gasifier 3.

[0063] Step 4: In the differential fluidized bed gasifier 3, the high-temperature circulating material and high-temperature superheated steam heat the differential fluidized bed gasifier 3 to 600-700 ° C, the mass ratio of steam to biomass char is 1-3:1, and CO2 is absorbed in situ. Biomass char and high-temperature steam react with the calcined products of limestone and dolomite and Ni-based catalyst to generate synthesis gas H2, CO, CO2, CH4 and H2S. At the same time, CaO and CO2 undergo in-situ absorption reaction to generate CaCO3, which promotes CO+H2O=H2+CO2 to In the forward direction, CaO reacts with H2S to generate CaS. The circulating material containing CaCO3 and CaS and the unreacted biochar (accounting for 10-15% of the total biochar weight) enter the fluidized bed calciner 22 through the return valve 27. Air is introduced into the fluidized bed calciner 22, and part of the charcoal therein is burned to heat the bed temperature to 850-900°C, so that CaCO3 decomposes into CaO and CO2, and CaS decomposes into CaO and SO2. The Ni-based catalyst removes carbon deposits and then enters the biomass circulating fluidized bed gasifier 2;

[0064] Step 5: The high-temperature synthesis gas (H2 volume ratio 80-85%, CO volume ratio 5-6%, CO2 volume ratio less than or equal to 3%, CH4 volume ratio 10%, H2S <100mg / Nm3) coming out from the top of the differential fluidized bed gasifier 3 3 , biochar gas production rate 2.0-2.5Nm 3 / kg; At the same time, CaO and MgO react with H2S in the differential fluidized bed steam gasifier 3. The reaction time in the differential fluidized bed steam gasifier 3 is not less than 10s, and 90% of H2S is removed. H2S <10mg / Nm 3 , to meet the need for the subsequent water gas shift reaction catalyst not to be deactivated) first enters the high-efficiency cyclone separator 2 5, separates the unreacted biomass char and circulating materials carried by the synthesis gas and sends them to the differential fluidized bed gasifier 3 for circulation gasification (to improve gasification efficiency); the high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 5 passes through the air preheater 3 12 and the superheater 1 8 in sequence, and is cooled to 350°C, and then enters the dust collector 14 (the dust collector 14 can be an existing mature ceramic filter tube dust collector 14 or a metal filter bag dust collector 14, or other dust collectors 14 that can withstand temperatures above 350°C) for dust removal (the dust removal efficiency of the dust collector 14 reaches more than 99.9%, and the dust content in the synthesis gas is ≤5mg / m 3 ), the temperature of the syngas after dust removal is 350°C, and the syngas enters the high-temperature water gas shift reactor 17 (WGS-1, reaction conditions: 350°C, SV = 1300-2700h -1), the synthesis gas with a temperature of 380-450°C enters the air preheater 11, which preheats the air to 250-300°C, and the synthesis gas temperature drops to 190-200°C and enters the low-temperature water gas shift reactor 18 (WGS-2, reaction conditions: 190-200°C, SV = 4600-5100h -1 ), steam / CO molar ratio ≥ 2, high and low temperature water gas shift reaction: CO + H2O = H2 + CO2, the total CO conversion rate is above 95%; the synthesis gas is heated to 250-260 ° C, and then enters the air preheater 10, the air is preheated from room temperature to 130-150 ° C, the synthesis gas temperature is reduced to 120-150 ° C, and then the synthesis gas enters the condenser 15 (existing mature technology), using a part of the feed water of the large coal-fired power generation boiler 16 to condense the water vapor in the synthesis gas, recover the latent heat of vaporization in the steam, and improve the thermal efficiency of the system; then the synthesis gas enters the organic amine scrubber 19 (mature technology), degassing After removing the remaining dust, trace amounts of H2S and more than 90% of CO2 from the synthesis gas, the temperature of the synthesis gas is reduced to 50-60°C. The organic amine aqueous solution absorbs the CO2 and is then regenerated and heated to 120-150°C. The CO2 and water vapor are then separated and condensed to obtain high-purity CO2 (a mature technology), thereby achieving CO2 capture and storage. The synthesis gas then enters the pressure swing adsorption system (PSA) 21 through the compressor 20 to obtain 99.9% H2. The exhaust gas from the pressure swing adsorption system 21 contains H2, CO, CO2 and CH4, which is sent through a pipeline to the large coal-fired power generation boiler 16 for combustion, and the released heat is used to generate electricity.

[0065] The fourth embodiment has the following effects: the biochar produced by the biomass circulating fluidized bed gasifier 2 enters the differential fluidized bed gasifier 3, where it absorbs CO2 in situ at 600-700°C, causing the reaction of CO + H2O = CO2 + H2 to proceed in a positive direction. This significantly reduces the CO2 concentration to below 3% and increases the H2 concentration to 80-85%, thereby reducing the pressure on the subsequent high-temperature water-steam shift reactor 17, low-temperature water-steam shift reactor 18, and organic amine scrubber 19. The combustible gas produced by the biomass circulating fluidized bed gasifier 2 is fed to a large coal-fired power generation boiler 16 for combustion, generating electricity with a power generation efficiency exceeding 40%.

[0066] The present invention is also applicable to replacing a "large coal-fired power generation boiler" with a "gas boiler", and burning the biomass gas generated by a circulating fluidized bed gasifier in the "gas boiler" for power generation or heat supply.

[0067] The differential fluidized bed structure of the differential fluidized bed gasifier 3 in the present invention has been disclosed in the invention patent with publication number CN102876339B, published on December 25, 2013, and entitled “A Gasification and Cracking Reaction Device”.

[0068] The above are only preferred specific implementation methods of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the patent of the present invention, who makes equivalent replacements or changes based on the technical solution of the patent of the present invention and the invention patent concept of the patent, should be covered by the scope of protection of the patent of the present invention.

Claims

1. A device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation, characterized by: It includes a screw feeder 1 (1-1), a screw feeder 2 (1-2), a biomass circulating fluidized bed gasifier (2), a differential fluidized bed gasifier (3), a high-efficiency cyclone separator 1 (4), a high-efficiency cyclone separator 2 (5), a superheater 1 (8), a superheater 2 (9), an air preheater 1 (10), an air preheater 2 (11), an air preheater 3 (12), a high-temperature gas blower (13), a dust collector (14), a condenser (15), a large coal-fired power generation boiler (16), a high-temperature water vapor shift reactor (17), a low-temperature water vapor shift reactor (18), an organic amine scrubber (19), a compressor (20) and a pressure swing adsorption system (21); The top of the screw feeder 1 (1-1) is provided with a biomass feeding port (27), the top of the screw feeder 2 (1-2) is provided with a circulating material feeding port (28), the discharge ports of the screw feeder 1 (1-1) and the screw feeder 2 (1-2) are respectively connected to the corresponding feed ports of the biomass circulating fluidized bed gasifier (2), the gas outlet at the top of the biomass circulating fluidized bed gasifier (2) is connected to the gas inlet of the high-efficiency cyclone separator 1 (4), and the high-efficiency cyclone separator The discharge port at the lower end of the first high-efficiency cyclone separator (4) is connected to the feed port of the differential fluidized bed gasifier (3) through the return valve (6), and the discharge port of the differential fluidized bed gasifier (3) is connected to the return inlet of the biomass circulating fluidized bed gasifier (2) through the return valve (7); the gas outlet at the top of the first high-efficiency cyclone separator (4) is connected to the gas inlet of the second superheater (9), and the gas outlet of the second superheater (9) is connected to the large coal-fired power generation boiler through the high-temperature gas blower (13). The gas inlet of the furnace (16) is connected; the synthesis gas outlet at the top of the differential fluidized bed gasification furnace (3) is connected to the synthesis gas inlet of the high-efficiency cyclone separator (5), and the discharge port at the lower end of the high-efficiency cyclone separator (5) is connected to the feed port 2 of the differential fluidized bed gasification furnace (3); the synthesis gas outlet at the top of the high-efficiency cyclone separator (5) is connected to the synthesis gas inlet of the air preheater (3) (12) and the superheater (8) in sequence, the synthesis gas outlet of the superheater (8) is connected to the inlet of the dust collector (14), the outlet of the dust collector (14) is connected to the high-temperature water vapor shift reactor (17), the air preheater (11), the low-temperature water vapor shift reactor (18), the air preheater (10), the condenser (15), the organic amine scrubber (19), the compressor (20) and the pressure swing adsorption system (21) in sequence, and the exhaust port of the pressure swing adsorption system (21) is connected to the furnace of the large coal-fired power generation boiler (16) through a pipeline.

2. The device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation according to claim 1, characterized in that: The steam outlet of the large coal-fired power generation boiler (16) is connected to the steam inlet of the steam turbine generator set (25) through a pipeline, and the low-pressure cylinder steam extraction outlet of the steam turbine generator set (25) is connected to the bottom wind chamber of the differential fluidized bed gasification furnace (3) through superheater 1 (8) and superheater 2 (9) in sequence.

3. The device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation according to claim 2, characterized in that: The outlet of the blower (26) is connected to the air inlet of the air preheater 1 (10), the air outlet of the air preheater 1 (10) is connected to the air inlet of the air preheater 2 (11), the air outlet of the air preheater 2 (11) is connected to the air inlet of the air preheater 3 (12), and the high-temperature air outlet of the air preheater 3 (12) is connected to the bottom air chamber of the biomass circulating fluidized bed gasifier (2).

4. A method for realizing the co-production of H2 by coupling biomass gasification with large-scale coal-fired power generation using the device of claim 3, characterized in that: The method comprises the following steps: Step 1: high-temperature air of 650-700°C is introduced into the bottom air chamber of the biomass circulating fluidized bed gasifier (2); at the same time, biomass and circulating materials are respectively fed into the biomass circulating fluidized bed gasifier (2) through screw feeder 1 (1-1) and screw feeder 2 (1-2), where the biomass is gasified and pyrolyzed, and the circulating materials are calcined and decomposed into CaO and MgO; the high-temperature gas of 900-950°C discharged from the gas outlet at the upper end of the biomass circulating fluidized bed gasifier (2) enters the high-efficiency cyclone separator 1 (4), where the circulating materials and biochar carried in the high-temperature gas are separated by the high-efficiency cyclone separator 1 (4), and are steam-activated through the return valve 1 (6) and fed into the differential fluidized bed gasifier (3), where the activated biochar reacts with 700-750°C high-temperature steam in the differential fluidized bed gasifier (3) to generate synthesis gas; Step 2: The high-temperature gas of 900-950°C discharged from the gas outlet at the top of the high-efficiency cyclone separator 1 (4) enters the superheater 2 (9), where the gas temperature is reduced to 450°C. After that, the gas is sent to the large-scale coal-fired power generation boiler (16) through the high-temperature gas blower (13) to generate electricity; Step 3: The high-temperature and high-pressure steam generated by the large-scale coal-fired power generation boiler (16) is sent to the steam turbine generator set (25) to generate electricity. The steam enters the superheater 1 (8) from the steam outlet of the steam turbine generator set (25) and is heated to 380°C. Then, it enters the superheater 2 (9) and is heated to 700-750°C. After that, the 700-750°C superheated steam enters the differential fluidized bed gasifier (3) from the bottom wind chamber of the differential fluidized bed gasifier (3). The mass ratio of steam to biochar is 1-3:

1. Biochar is the product of biomass gasification and is 25-30% of the biomass feed amount. The flue gas generated by the large-scale coal-fired power generation boiler (16) enters the chimney (24) through the flue gas fan (23) and is discharged into the atmosphere. Step 4: In the differential fluidized bed gasifier (3), the high-temperature circulating material and the high-temperature superheated steam heat the differential fluidized bed gasifier (3) to 780-900°C. The biochar reacts with the high-temperature steam at this temperature to generate synthesis gas. The synthesis gas is composed of H2, CO, CO2, CH4 and H2S, wherein: H2 accounts for 75%-77% by volume, CO accounts for 7-8% by volume, CO2 accounts for 6.5-8.5% by volume, CH4 accounts for 6.5-8% by volume, and the original H2S is <100mg / Nm 3 , biochar gas production rate 2.5-3.6Nm 3 / kg; At the same time, the CaO and MgO formed after the calcination of limestone and dolomite react with H2S to remove 90% of H2S, and H2S <10 mg / Nm 3 ; Step 5: The high-temperature synthesis gas coming out of the top of the differential fluidized bed gasifier (3) first enters the high-efficiency cyclone separator II (5), and the unreacted biomass charcoal and bed material carried by the synthesis gas are separated and sent to the differential fluidized bed gasifier (3) for circulation gasification; the synthesis gas coming out of the top of the high-efficiency cyclone separator II (5) passes through the air preheater III (12) and the superheater I (8) in turn, and is cooled to 350°C, and then enters the dust collector (14) for dust removal. The synthesis gas after dust removal enters the high-temperature water vapor shift reactor (17), and then passes through the air preheater II (11) to cool to 190-200°C. , then enters the low-temperature water-steam shift reactor (18), and after the temperature rises to 250-260°C, enters the air preheater (10), preheating the air from room temperature to 130-150°C, and the synthesis gas temperature drops to 120-150°C, and then enters the condenser (15) and the organic amine scrubber (19) in sequence to remove CO2 and impurities in the synthesis gas, and finally enters the pressure swing adsorption system (21) through the compressor (20) to obtain 99.9% H2. The gas discharged from the pressure swing adsorption system (21) is sent to the large coal-fired power generation boiler (16) through a pipeline for combustion, and the released heat is used for power generation.

5. A device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation, characterized by: It includes a screw feeder 1 (1-1), a screw feeder 2 (1-2), a biomass circulating fluidized bed gasifier (2), a differential fluidized bed gasifier (3), a fluidized bed calciner (22), a high-efficiency cyclone separator 1 (4), a high-efficiency cyclone separator 2 (5), a superheater 1 (8), a superheater 2 (9), an air preheater 1 (10), an air preheater 2 (11), an air preheater 3 (12), a high-temperature gas blower (13), a dust collector (14), a condenser (15), a large coal-fired power generation boiler (16), a high-temperature water vapor shift reactor (17), a low-temperature water vapor shift reactor (18), an organic amine scrubber (19), a compressor (20) and a pressure swing adsorption system (21); The top of the screw feeder 1 (1-1) is provided with a biomass feeding port (27), the top of the screw feeder 2 (1-2) is provided with a circulating material feeding port (28), the discharge ports of the screw feeder 1 (1-1) and the screw feeder 2 (1-2) are respectively connected to the corresponding feed ports of the biomass circulating fluidized bed gasification furnace (2), the gas outlet at the top of the biomass circulating fluidized bed gasification furnace (2) is connected to the gas inlet of the high-efficiency cyclone separator 1 (4), and the lower end of the high-efficiency cyclone separator 1 (4) is connected to the gas inlet of the high-efficiency cyclone separator 1 (4). The discharge port of the differential fluidized bed gasifier (3) is connected to the feed port of the differential fluidized bed gasifier (3) through the return valve 1 (6), the discharge port of the differential fluidized bed gasifier (3) is connected to the feed port of the fluidized bed calcining bed (22) through the return valve 2 (7), and the discharge port of the fluidized bed calcining bed (22) is connected to the return inlet of the biomass circulating fluidized bed gasifier (2); the gas outlet at the top of the high-efficiency cyclone separator 1 (4) is connected to the gas inlet of the superheater 2 (9), and the gas outlet of the superheater 2 (9) is connected to the feed port of the fluidized bed calcining bed (22) through the high-efficiency cyclone separator 1 (4). The warm gas blower (13) is connected to the gas inlet of the large coal-fired power generation boiler (16); the synthesis gas outlet at the top of the differential fluidized bed gasifier (3) is connected to the synthesis gas inlet of the high-efficiency cyclone separator (5), and the discharge port at the lower end of the high-efficiency cyclone separator (5) is connected to the feed port 2 of the differential fluidized bed gasifier (3); the synthesis gas outlet at the top of the high-efficiency cyclone separator (5) is connected to the synthesis gas inlet of the air preheater (12) and the superheater (8) in turn, and the superheater ( The syngas outlet of the reactor 8 is connected to the inlet of the dust collector (14), and the outlet of the dust collector (14) is connected in sequence to the high-temperature steam shift reactor (17), the second air preheater (11), the low-temperature steam shift reactor (18), the first air preheater (10), the condenser (15), the organic amine scrubber (19), the compressor (20) and the pressure swing adsorption system (21). The exhaust port of the pressure swing adsorption system (21) is connected to the furnace of the large coal-fired power generation boiler (16) through a pipeline.

6. The device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation according to claim 5, characterized in that: The steam outlet of the large coal-fired power generation boiler (16) is connected to the steam inlet of the steam turbine generator set (25) through a pipeline, and the low-pressure cylinder steam extraction outlet of the steam turbine generator set (25) is connected to the bottom wind chamber of the differential fluidized bed gasification furnace (3) through superheater 1 (8) and superheater 2 (9) in sequence.

7. The device for co-producing H2 by coupling biomass gasification with large-scale coal-fired power generation according to claim 6, characterized in that: The outlet of the blower (26) is connected to the air inlet of the air preheater 1 (10), the air outlet of the air preheater 1 (10) is connected to the air inlet of the air preheater 2 (11), the air outlet of the air preheater 2 (11) is connected to the air inlet of the air preheater 3 (12), and the high-temperature air outlet of the air preheater 3 (12) is connected to the bottom air chamber of the biomass circulating fluidized bed gasifier (2).

8. A method for achieving H2 co-production by coupling biomass gasification with large-scale coal-fired power generation using the device of claim 7, characterized in that: The method comprises the following steps: Step 1: medium-temperature air of 350-400°C is introduced into the bottom air chamber of the biomass circulating fluidized bed gasifier (2); at the same time, biomass and circulating materials are fed into the biomass circulating fluidized bed gasifier (2) through the screw feeder 1 (1-1) and the screw feeder 2 (1-2), where the biomass is gasified and pyrolyzed, and the circulating materials are composed of limestone, dolomite and Ni catalyst; the 750-850°C high-temperature gas discharged from the gas outlet of the biomass circulating fluidized bed gasifier (2) carries the biomass charcoal and the circulating materials into the high-efficiency cyclone separator 1 (4), and the circulating materials and biomass charcoal carried in the high-temperature gas are separated by the high-efficiency cyclone separator 1 (4), and are steam-activated through the return valve 1 (6) and fed into the differential fluidized bed gasifier (3); Step 2: The high-temperature gas discharged from the gas outlet at the top of the high-efficiency cyclone separator 1 (4) enters the superheater 2 (9), where the gas temperature is reduced to 450°C. Thereafter, the gas is sent to the large-scale coal-fired power generation boiler (16) through the high-temperature gas blower (13) to generate electricity; Step 3: The high-temperature and high-pressure steam generated by the large-scale coal-fired power generation boiler (16) is sent to the steam turbine generator set (25) through a pipeline to generate electricity. The steam of the steam turbine generator set (25) enters the superheater 1 (8) and is heated to 380°C. Then, it enters the superheater 2 (9) and is heated to 550-600°C superheated steam. After that, the 550-600°C superheated steam enters the differential fluidized bed gasifier (3) from the bottom wind chamber of the differential fluidized bed gasifier (3); Step 4: In the differential fluidized bed gasifier (3), the high-temperature circulating material and high-temperature superheated steam heat the differential fluidized bed gasifier (3) to 600-700℃, in-situ absorb CO2, and the biomass char reacts with the high-temperature steam under the action of the calcined products of limestone and dolomite and the Ni-based catalyst to generate synthesis gas H2, CO, CO2, CH4 and H2S. At the same time, CaO reacts with CO2 in-situ to generate CaCO3, promoting the reaction of CO+H2O=H2+CO2 in the positive direction. CaO reacts with H2S to generate CaS, and the circulating material containing CaCO3 and CaS and the unreacted biochar enter the fluidized bed calcining bed (22) through the return valve 2 (7). Air is introduced into the fluidized bed calcining bed (22), and part of the charcoal therein is burned to heat the bed temperature to 850-900°C, so that CaCO3 is decomposed into CaO and CO2, and CaS is decomposed into CaO and SO2. The Ni-based catalyst eliminates carbon deposits and then enters the biomass circulating fluidized bed gasifier (2); Step 5: The high-temperature synthesis gas coming out of the top of the differential fluidized bed gasifier (3) first enters the high-efficiency cyclone separator II (5), and the unreacted biomass charcoal and circulating materials carried by the synthesis gas are separated and sent to the differential fluidized bed gasifier (3) for circulation gasification; the high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator II (5) passes through the air preheater III (12) and the superheater I (8) in turn and is cooled to 350°C, and then enters the dust collector (14) for dust removal, and then the synthesis gas enters the high-temperature water vapor shift reactor (17), and the synthesis gas with a temperature rise of 380-450°C enters the air preheater II (11), and the synthesis gas temperature is reduced to 19 0-200℃ and enters the low-temperature water-steam shift reactor (18), the synthesis gas is heated to 250-260℃, and then enters the air preheater (10), the air is preheated from room temperature to 130-150℃, the synthesis gas temperature is reduced to 120-150℃, and then the synthesis gas enters the condenser (15) and the organic amine scrubber (19), the synthesis gas temperature is reduced to 50-60℃, and then the synthesis gas enters the pressure swing adsorption system (21) through the compressor (20) to obtain 99.9% H2. The gas discharged from the pressure swing adsorption system (21) is sent to the large coal-fired power generation boiler (16) through a pipeline for combustion, and the released heat is used for power generation.

9. The method for co-producing H2 by biomass gasification coupled with large-scale coal-fired power generation according to claim 8, characterized in that: In step 1, the mass ratio of limestone, dolomite and Ni-based catalyst is 1:1:

1.

10. The method for co-producing H2 by biomass gasification coupled with large-scale coal-fired power generation according to claim 8, characterized in that: In step 5, the synthesis gas enters the organic amine scrubber (19) to remove the remaining dust, trace H2S and more than 90% of CO2 in the synthesis gas. The organic amine aqueous solution absorbs CO2 and is regenerated and heated to 120-150°C. Then, CO2 and water vapor are decomposed and condensed to obtain high-purity CO2.

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