A Thermal Hydrogen Co-production System and Method Coupling Solar Energy and Biomass Energy

Abstract

The present invention discloses a thermal hydrogen co-production system and method coupling solar energy and biomass energy. The system includes a microwave reactor, a biomass gasifier, a combustion reactor, an air preheater, a catalytic reforming reactor, a solar thermal energy storage system, a CO2 separation device, and an activated carbon preparation device. By combining microwave baking pretreatment, biomass gasification for hydrogen production, and chemical looping combustion, the problem of high tar content in syngas is solved, the quality of syngas is improved, and efficient separation of CO2 is achieved; the high-temperature molten salt in the solar thermal energy storage system is used to provide heat energy for the catalytic reforming reaction of syngas, reducing the energy consumption of the catalytic reforming reaction; the system can not only produce hydrogen but also achieve near-zero CO2 emissions; the input energies in the system, biomass energy and solar energy, both belong to renewable energies. While realizing the efficient and clean utilization of biomass resources and solar energy, it also avoids the costs of large-scale collection and storage of biomass raw materials.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production, and particularly relates to a solar energy-coupled biomass thermochemical hydrogen co-production system and method. Background Art

[0002] Hydrogen energy is a clean, efficient, and carbon-free energy source, with advantages such as diverse sources, high energy density, and wide application range. Thermochemical hydrogen production from fossil fuels (accounting for about 96% of the total production) and electrolytic water hydrogen production (accounting for about 4%) are the main current hydrogen production methods. During the process of hydrogen production from fossil fuels, a large amount of polluting gases such as NO x and SO x are emitted, significantly threatening environmental safety. Moreover, fossil fuels are non-renewable energy sources; electrolytic water hydrogen production has advantages such as a simple process flow, low pollution, and high hydrogen purity, but it has a large power consumption and high requirements for water quality, and is limited in terms of economy. The environmental pollution and non-sustainability problems of hydrogen production from fossil fuels, as well as the high energy consumption problem of electrolytic water hydrogen production, have promoted the production of hydrogen from renewable clean energy to become the inevitable path for the future development of hydrogen energy technology.

[0003] Biomass energy is solar energy fixed on the earth by plant photosynthesis, with huge development potential. During the entire carbon cycle process, the carbon source of biomass energy does not increase the total amount of carbon in the atmosphere, and it is an internationally recognized zero-carbon renewable energy source. If combined with BECCS (Bioenergy with Carbon Capture and Storage) technology, biomass energy will achieve negative carbon emissions. It is estimated that by the middle of this century, various biomass alternative fuels produced by new processes will account for more than 40% of the global total energy consumption. Therefore, the hydrogen production route based on low-carbon, renewable biomass energy is a true green hydrogen technology.

[0004] Biomass hydrogen production is mainly divided into thermochemical hydrogen production and biological hydrogen production. Among them, biomass thermochemical hydrogen production is a technology that converts biomass raw materials into hydrogen-rich gases through thermochemical methods and then produces hydrogen through separation and purification. Thermochemical hydrogen production mainly includes gasification, supercritical water gasification, bio-oil reforming, and biomass pyrolysis-steam reforming for hydrogen production, etc.; biological hydrogen production is a bioengineering technology that uses microbial metabolism to produce hydrogen, mainly including anaerobic fermentation for hydrogen production and photosynthetic biological hydrogen production. Compared with thermochemical methods, biological hydrogen production has the advantages of energy conservation, renewable, and no consumption of mineral resources. However, the reaction rate of biological hydrogen production is slow, the hydrogen production efficiency is very low, and the requirements of microorganisms for the environment are relatively harsh, which are the main factors restricting biological hydrogen production. In the existing biomass hydrogen production processes, biomass gasification for hydrogen production technology has received extensive attention from scholars. "A biomass gasification hydrogen production system and method" (201010118131.1) adopts a method of combining biomass gasification for hydrogen production with chemical-looping combustion, which can achieve nearly zero emissions of CO2 while producing hydrogen using the system. However, this system does not consider the problem of high tar production during the biomass gasification process, which is likely to cause pipeline blockage problems; the multi-stage transportation and separation of heat carriers will also cause a large amount of heat loss; the scheme of using a hydrogen separation device to separate H2 from combustible gases (including H2, CO, CH4, CO2, H2O, and a small amount of hydrocarbon compounds) also requires a large amount of energy consumption. In addition, the biomass gasification hydrogen production process also has problems such as high catalyst cost and easy deactivation. Therefore, the existing biomass gasification hydrogen production systems need to be continuously improved, and new processes also need to be continuously proposed to achieve the large-scale application of biomass hydrogen production technology with high efficiency and low cost at an early date. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a solar-coupled biomass energy thermal hydrogen co-production system. By sequentially subjecting biomass raw materials to microwave baking pretreatment and gasification, gasification syngas is obtained; then a catalytic reforming reactor is used to catalytically reform the syngas to produce hydrogen-rich gas; and a solar thermal device is used to provide the heat energy required for the reaction for the catalytic reforming reactor. By coupling and utilizing the clean and renewable biomass energy and solar energy, the efficient thermal conversion and high-value utilization of renewable energy (biomass energy and solar energy) can be achieved.

[0006] To achieve the above object, on the one hand, the present invention provides a thermal hydrogen co-production system integrating solar energy and biomass energy, including an activated carbon preparation device, a microwave reactor, a biomass gasifier, a combustion reactor, an air preheater, a catalytic reforming reactor, a solar thermal energy storage system and a CO2 separation device; the biomass outlet of the microwave reactor is respectively connected to the feed inlets of the biomass gasifier and the activated carbon preparation device, the carbon outlet of the biomass gasifier is connected to the combustion reactor, the biomass gasifier and the combustion reactor are both provided with water-cooled walls and water-cooled wall headers, the gas outlets of the microwave reactor and the biomass gasifier and the steam outlet of the water-cooled wall header of the combustion reactor are connected to the gas inlet of the catalytic reforming reactor, the gas outlet of the catalytic reforming reactor is connected to the CO2 separation device, and the CO2 separation device is connected with a CO2 storage tank and an H2 storage tank; an air preheater is arranged at the flue gas outlet of the combustion reactor, and the high-temperature air outlet of the air preheater is connected to the air inlet of the combustion reactor and the heat user; the heat storage medium inlet and outlet of the solar thermal energy storage system are connected to the heat storage medium inlet and outlet of the catalytic reforming reactor; the heat storage medium outlet of the solar thermal energy storage system is connected to the heat storage medium inlet of the activated carbon preparation device; the feed inlet of the biomass gasifier serves as the inlet of CaO and the metal oxygen carrier; the steam outlet of the water-cooled wall header of the biomass gasifier is respectively connected to the steam inlets of the biomass gasifier and the activated carbon preparation device.

[0007] The solar thermal energy storage system includes a low-temperature medium storage tank, a solar thermal device and a high-temperature medium storage tank connected in sequence. The inlet of the low-temperature medium storage tank serves as the heat storage medium inlet of the solar thermal energy storage system, and the outlet of the high-temperature medium storage tank serves as the heat storage medium outlet of the solar thermal energy storage system. The solar thermal device adopts a tower-type solar thermal device, a trough-type solar thermal device or a dish-type solar thermal device; the heat storage medium is an alkali metal molten salt.

[0008] The solar thermal device adopts a solar reactor. The middle part of the solar reactor is an absorption cavity, the absorption cavity is open, and a heat storage medium heating cavity is arranged outside the absorption cavity; a quartz glass window is arranged on the open side of the absorption cavity, the surface of the absorption cavity is coated with a coating with high solar absorptivity and low thermal emissivity, and the surface of the quartz glass window is plated with a low-reflectivity coating for reducing heat loss.

[0009] A stirring device is arranged at the top of the microwave reactor, and a first screw conveyor is arranged at the inlet of the microwave reactor; the combustible gas outlet of the microwave reactor is connected with a first cyclone separator, a second cyclone separator is arranged at the gas outlet of the biomass gasifier, and a third cyclone separator is arranged between the flue gas outlet of the combustion reactor and the air preheater; the particulate matter outlet of the second cyclone separator is connected to the biomass gasifier through a return feeder, the particulate matter outlets of the first cyclone separator and the third cyclone separator are connected to the feed inlet of the biomass gasifier, and induced draft fans are arranged at the gas outlets of the first cyclone separator, the second cyclone separator and the third cyclone separator.

[0010] Both ends of the water wall are respectively connected to the upper header of the water wall and the lower header of the water wall. The lower header of the water wall is connected to the feed water system. A carbon outlet is provided at the bottom of the biomass gasifier, a fourth feed inlet is provided on the combustion reactor, and the carbon outlet is connected to the fourth feed inlet through a second screw conveyor.

[0011] The main body of the catalytic reforming reactor is cylindrical. The gas passage of the catalytic reforming reactor uses a metal tube with external fin enhancement, and the metal tube is spirally arranged inside the catalytic reforming reactor; a catalyst bed for the catalytic reforming reaction of syngas is arranged in the gas passage of the catalytic reforming reactor; the gas flow direction in the catalytic reforming reactor is opposite to the flow direction of the heat storage medium; the main body material of the catalytic reforming reactor is austenitic stainless steel resistant to molten salt corrosion.

[0012] The activated carbon preparation device is a rotary kiln reactor.

[0013] The CO2 separation device is a pressure swing adsorption purification device or a membrane separation device; the activated carbon prepared in the activated carbon preparation device is used as the adsorbent in the pressure swing adsorption purification device.

[0014] The catalyst in the catalytic reforming reactor is a carbon-based catalyst loaded with a transition metal or its oxide, and the carbon-based carrier is the activated carbon prepared in the activated carbon preparation device.

[0015] On the other hand, a method for co-producing heat and hydrogen by coupling solar energy and biomass energy is provided. After the biomass raw material is heated and baked by microwave, a part of the solid product is used to prepare activated carbon, and another part of the solid product undergoes a biomass gasification reaction under the action of water vapor to produce gasification syngas; CaO and a metal oxygen carrier are added during the biomass gasification reaction; the coke remaining after the biomass gasification and the low-valent metal oxides or metal particles generated by the gasification are burned, and the high temperature generated by the combustion is used to calcine the CaCO3 generated by the gasification; the CaO and metal oxides generated by the combustion and the heat carried by them participate in the biomass gasification reaction again; the flue gas after combustion heats the air, and a part of the heated high-temperature air participates in the biomass gasification reaction, and another part is supplied to heat users; the gaseous product, gasification syngas after the biomass raw material is heated and baked by microwave, and the water vapor generated in the water wall undergo a catalytic reforming reaction under the heating condition of the heat storage medium to produce hydrogen-rich gas, and the H2 and CO2 in the hydrogen-rich gas product are separated and recovered; the heat storage medium is heated by a solar thermal device; a part of the water vapor generated in the water wall participates in the biomass gasification reaction again, and another part participates in the preparation of activated carbon. The heat storage medium is used for heating during the preparation of activated carbon, and the generated activated carbon is used as the catalyst carrier during the catalytic reforming reaction and the adsorbent during the separation of hydrogen-rich gas.

[0016] The gasification synthesis gas is separated and purified, and the generated particulate matter and fly ash are recycled and participate in the biomass gasification reaction again. The flue gas generated after the combustion of the coke remaining from the biomass gasification is separated and purified, and the generated particulate matter and fly ash are recycled to participate in the biomass gasification reaction, and the flue gas is used to heat the air.

[0017] The biomass gasification reaction is carried out in a biomass gasifier, and the combustion reaction is carried out in a combustion reactor. A carbon outlet is opened at the bottom of the biomass gasifier, and a fourth feed inlet is opened in the combustion reactor. The carbon outlet is connected to the fourth feed inlet through a second screw conveyor; the residual carbon remaining after the gasification reaction, as well as the low-valence metal oxides or metal particles and CaCO3 generated by the gasification reaction, are discharged from the carbon outlet at the bottom of the gasifier and enter the combustion reactor through the second screw conveyor through the fourth feed inlet for combustion reaction; water-cooled walls are provided on the biomass gasifier and the combustion reactor. The water-cooled walls are connected with an upper header and a lower header. After the feed water enters the lower header and is heated by the water-cooled walls, the steam enters the upper header.

[0018] The reaction temperature of the microwave reactor is 200 to 300 °C; the reaction temperature of the activated carbon preparation device is 300 to 400 °C; the reaction temperature of the biomass gasifier is 600 to 700 °C; the reaction temperature of the combustion reactor is 900 to 1000 °C, and the temperature of the catalytic reforming reactor is 400 to 500 °C.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] The present invention can prepare gasification synthesis gas by combining microwave pre-baking of biomass raw materials with biomass gasification, which helps to solve the problem of high tar content in the synthesis gas; using microwave heating technology to pretreat biomass raw materials has higher thermal efficiency and raw material adaptability compared with traditional drying or baking technologies, and has a better pretreatment effect especially on biomass with high moisture content; during the gasification process, water vapor is used as the gasification agent, metal oxides are used as the oxygen carrier and heat carrier, which can improve the quality of the gasification synthesis gas and avoid the dilution of the synthesis gas by nitrogen, and at the same time increase the hydrogen yield in the synthesis gas; moreover, adding CaO to the biomass gasifier helps to absorb the CO2 generated during the gasification process, relieve the subsequent CO2 separation and purification pressure; it can also reduce the CO2 partial pressure in the gasifier and promote the gasification reaction.

[0021] The system of the present invention uses a solar thermal device to heat the alkali metal molten salt and uses a high-temperature heat storage medium to provide the heat energy required for the catalytic reforming reaction of the synthesis gas, solving the problem of high energy consumption in the current catalytic reforming reaction.

[0022] The hot hydrogen co-production system of the present invention can achieve nearly zero CO2 emissions. Moreover, the activated carbon produced by the activated carbon preparation device can also fix a part of the carbon source and adsorb a part of the carbon source when used as an adsorbent, thereby achieving negative carbon emissions while producing hydrogen. In addition to obtaining high-purity hydrogen, the present invention can also obtain high-purity CO2 gas, which is convenient for storage or other uses.

[0023] The energy input into the hot hydrogen co-production system of the present invention is biomass energy and solar energy, both of which belong to renewable energy sources. While realizing the efficient and clean utilization of biomass resources and solar energy, it also avoids the costs of large-scale collection and storage of biomass raw materials. Brief Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of the solar energy-coupled biomass energy hot hydrogen co-production system of the present invention.

[0025] Figure 2 It is a schematic structural diagram of the catalytic reforming reactor of the present invention.

[0026] Figure 3 It is a schematic structural diagram of the solar thermal device of the present invention.

[0027] The reference numerals shown in the figure are: 1 - activated carbon preparation device, 2 - biomass outlet, 3 - first screw conveyor, 4 - first feed inlet, 5 - microwave reactor, 6 - combustible gas outlet, 7 - first cyclone separator, 8 - first induced draft fan, 9 - first water-cooled wall upper header, 10 - water-cooled wall, 11 - biomass gasifier, 12 - second cyclone separator, 13 - second induced draft fan, 14 - second water-cooled wall upper header, 15 - combustion reactor, 16 - third cyclone separator, 17 - third induced draft fan, 18 - air preheater, 19 - catalytic reforming reactor, 20 - low-temperature molten salt storage tank, 21 - solar reactor, 22 - high-temperature molten salt storage tank, 23 - CO2 separation device, 24 - CO2 storage tank, 25 - H2 storage tank, 26 - second water-cooled wall lower header, 27 - air inlet, 28 - fourth feed inlet, 29 - first water-cooled wall lower header, 30 - second screw conveyor, 31 - carbon outlet, 32 - steam inlet, 33 - third feed inlet, 34 - second feed inlet, 191 - gas channel, 192 - molten salt channel, 193 - gas inlet, 194 - low-temperature molten salt outlet, 195 - high-temperature molten salt inlet, 196 - hydrogen-rich gas outlet, 211 - molten salt heating chamber, 212 - low-temperature molten salt inlet, 213 - quartz glass window, 214 - high-temperature molten salt outlet, 215 - absorption cavity. Detailed Embodiments

[0028] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0029] The schematic structural diagram of the thermal hydrogen co-production system coupling solar energy and biomass energy provided by the present invention is as follows Figure 1 shown, including an activated carbon preparation device 1, a microwave reactor 5, a biomass gasifier 11, a combustion reactor 15, an air preheater 18, a catalytic reforming reactor 19, a solar reactor 21, and a CO2 separation device 23, wherein: The microwave reactor 5 is used to bake and pre-treat biomass raw materials to produce high-quality biomass products, meeting the raw material requirements of the biomass gasifier 11 and the activated carbon preparation device, and generating combustible gas to meet the fuel requirements of the catalytic reforming reactor 19. A stirring device is provided at the top of the microwave reactor 5 to ensure the full reaction of biomass raw materials; a first screw conveyor 3 is provided at the inlet of the microwave reactor 5. Using the microwave reactor 5 to bake and pre-treat biomass raw materials can significantly improve the fuel quality of biomass, such as increasing carbon content, calorific value, and energy density, etc. At the same time, it can remove some volatile components in biomass and reduce the tar production in the subsequent thermal utilization process of biomass (including combustion, pyrolysis, and gasification, etc.). The biomass outlet 2 of the microwave reactor 5 is respectively connected to the activated carbon preparation device 1 and the second feed port 34 of the biomass gasifier 11. The combustible gas outlet 6 of the microwave reactor 5 is connected to a first cyclone separator 7 and enters the catalytic reforming reactor 19 through a first induced draft fan 8 from the gas inlet 193.

[0030] The biomass gasifier 11 is used for the gasification reaction of biomass under the action of water vapor to produce syngas, meeting the fuel demand of the catalytic reforming reactor 19. A water-cooled wall 10 is provided on the biomass gasifier 11. The upper and lower parts of the water-cooled wall 10 are respectively connected to the upper header 9 of the first water-cooled wall and the lower header 29 of the first water-cooled wall. The lower header 29 of the first water-cooled wall is connected to the feed water. The steam outlet of the upper header 9 of the first water-cooled wall is connected to the steam inlet of the activated carbon preparation device 1 and the water vapor inlet 32 of the biomass gasifier 11. The water vapor generated in the water-cooled wall 10 of the biomass gasifier 11 is used to meet the water vapor demand of the gasification reaction. CaO is introduced into the biomass gasifier 11 to participate in the gasification reaction. On the one hand, the carbonation reaction of CaO with carbon dioxide is used to reduce the concentration of carbon dioxide in the syngas and promote the gasification reaction. On the other hand, the reaction of CaO with carbon dioxide is an exothermic reaction, which can also provide part of the heat energy for the gasification reaction. At the same time, a metal oxygen carrier is introduced into the biomass gasifier 11. The metal oxygen carrier serves as an oxygen carrier to provide oxygen for the gasification reaction and also serves as a heat carrier to provide the required heat for the gasification reaction. A second feed port 34 and a third feed port 33 are provided on the side wall of the biomass gasifier 11. The second feed port 34 of the biomass gasifier 11 is respectively connected to the biomass outlet 2 of the microwave reactor 5 and the solid particle outlet of the first cyclone separator 7. The third feed port 33 of the biomass gasifier 11 is used to transport CaO and the metal oxygen carrier and is connected to the solid particle outlet of the third cyclone separator 16. The syngas outlet of the biomass gasifier 11 is connected to the second cyclone separator 12, and is successively connected to the second induced draft fan 13, the catalytic reforming reactor 19, and the CO2 separation device 23. The gas outlet of the CO2 separation device 23 is connected to the CO2 storage tank 24 and the H2 storage tank 25. The carbon outlet 31 of the biomass gasifier 11 is connected to the fourth feed port 28 of the combustion reactor 15 through the second screw conveyor 30. The metal oxygen carrier adopts particles such as Fe2O3, NiO, or CuO.

[0031] The combustion reactor 15 is used for burning the coke remaining after biomass gasification and the low-valence metal oxides or metal particles generated by gasification, and calcining the CaCO3 generated by gasification by using the high temperature generated by combustion. When the CaO and the metal oxygen carrier generated by combustion leave the combustion reactor 15, they carry a large amount of heat, serving as an oxygen carrier and a heat carrier to provide the required oxygen and heat for biomass gasification. A water-cooled wall is provided on the combustion reactor 15. The water-cooled wall is connected to the lower header 26 of the second water-cooled wall and the upper header 14 of the second water-cooled wall. The steam outlet of the upper header 14 of the second water-cooled wall is connected to the steam inlet of the catalytic reforming reactor 19. The lower header 26 of the second water-cooled wall is connected to the feed water. The flue gas outlet of the combustion reactor 15 is successively connected to the third cyclone separator 16, the third induced draft fan 17, and the air preheater 18. The air inlet 27 at the bottom of the combustion reactor 15 is connected to the high-temperature air outlet of the air preheater 18.

[0032] The air preheater 18 utilizes the high-temperature heat energy of the flue gas to preheat the air to meet the air required by the combustion reactor 15; the air preheater 18 is a tubular air preheater with internal and external enhanced fins, which can preheat oxygen and air to 400-450 °C; the high-temperature air outlets of the air preheater 18 are respectively connected to the air inlet 27 of the combustion reactor 15 and the heat user.

[0033] Reference Figure 2 , the catalytic reforming reactor 19 is used for the catalytic reforming reaction of gasified syngas and water vapor to produce hydrogen-rich gas, including a gas channel 191, a molten salt channel 192, a gas inlet 193, a low-temperature molten salt outlet 194, a high-temperature molten salt inlet 195, and a hydrogen-rich gas outlet 196. The main body of the catalytic reforming reactor 19 is cylindrical. The gas channel 191 of the catalytic reforming reactor 19 is a metal tube with external fin enhancement, and the metal tube is spirally arranged inside the catalytic reforming reactor 19; a catalyst bed for the catalytic reforming reaction of syngas is arranged in the gas channel 191 of the catalytic reforming reactor 19; the gas flow direction in the catalytic reforming reactor 19 is opposite to the molten salt flow direction; the main body material of the catalytic reforming reactor 19 is austenitic stainless steel resistant to molten salt corrosion; the catalyst in the catalytic reforming reactor 19 is a carbon-based catalyst loaded with transition metals or their oxides, and the carbon-based carrier is the activated carbon prepared in the activated carbon preparation device 1.

[0034] Reference Figure 3 , for the solar thermal device, the present invention provides a solar reactor 21, which is used to heat the alkali metal molten salt, and further provide the heat energy required for the catalytic reforming reaction of syngas in the catalytic reforming reactor 19; the solar reactor 21 includes a molten salt heating chamber 211, a low-temperature molten salt inlet 212, a quartz glass window 213, a high-temperature molten salt outlet 214, and an absorption cavity 215; a quartz glass window 213 is arranged on the outside of the solar reactor 21, the absorption cavity 215 is arranged in the middle of the solar reactor 21, and a molten salt heating chamber 211 is arranged outside the absorption cavity 215; the molten salt in the molten salt heating chamber 211 is a ternary nitrate of K, Na, and Li; the surface of the quartz glass window 213 is coated with a low-reflectivity coating for reducing heat loss; the surface of the absorption cavity 215 is coated with a coating with high solar absorptivity and low thermal emissivity, which can absorb 95% of solar energy; the high-temperature molten salt outlet 214 of the solar reactor 21 is connected to the high-temperature molten salt storage tank 22, and the outlet of the high-temperature molten salt storage tank 22 is respectively connected to the high-temperature molten salt inlet 195 of the catalytic reforming reactor 19 and the activated carbon preparation device 1; the low-temperature molten salt outlet 194 of the catalytic reforming reactor 19 is connected to the low-temperature molten salt storage tank 20, and the outlet of the low-temperature molten salt storage tank 20 is connected to the low-temperature molten salt inlet 212 of the solar reactor 21.

[0035] The activated carbon preparation device 1 is used to prepare the activated carbon required for the catalytic reforming reactor 19 and the CO2 separation device 23. The activated carbon preparation device 1 is a rotary kiln reactor. The activated carbon preparation device 1 is respectively connected to the biomass outlet 2 of the microwave reactor 5, the steam outlet of the first water-cooled wall upper header 9, and the outlet of the high-temperature molten salt storage tank 22.

[0036] The CO2 separation device 23 is used to separate H2 and CO2 in the hydrogen-rich gas product. The CO2 separation device 23 is a pressure swing adsorption purification device or a membrane separation device; the activated carbon prepared in the activated carbon preparation device 1 is used as the adsorbent in the pressure swing adsorption purification device.

[0037] The reaction temperature of the microwave reactor 5 is 200 - 300 °C; the reaction temperature of the activated carbon preparation device 1 is 300 - 400 °C; the reaction temperature of the biomass gasifier 11 is 600 - 700 °C; the reaction temperature of the combustion reactor 15 is 900 - 1000 °C; the temperature of the catalytic reforming reactor 19 is 400 - 500 °C.

[0038] Induced draft fans are provided at the gas outlets of the first cyclone separator 7, the second cyclone separator 12, and the third cyclone separator 16.

[0039] The energy input into the hot hydrogen co-production system described in the present invention is biomass energy and solar energy, both of which belong to renewable energy sources.

[0040] Example:

[0041] Refer to Figure 1, when the system is running, first turn on the switch of the microwave reactor 5 and set the temperature to 250 °C. After the temperature rises to the target temperature, the biomass particles that have undergone crushing treatment are transported from the first feed inlet 4 to the microwave reactor 5. The moisture content of the biomass particles is less than 20 wt.% and the particle size is not greater than 10 mm. The biomass particles are subjected to baking pretreatment at a temperature of 250 °C to produce a biomass product with a high carbon content and a large energy density; a small amount of combustible gas is also generated, the main components of which are H2, CO, CO2, CH4, H2O and light hydrocarbon gases, and at the same time contains a small amount of gaseous tar. The combustible gas generated by biomass baking enters the first cyclone separator 7 through the combustible gas outlet 6 for purification treatment to remove a small amount of carbon particles and fly ash in the combustible gas. The purified combustible gas enters the catalytic reforming reactor 19 through the first induced draft fan 8 from the gas inlet 193 for catalytic reforming reaction. A part of the biomass after baking treatment enters the activated carbon preparation device 1 to be used for preparing activated carbon under the action of water vapor and alkali metal molten salt; another part of the biomass is mixed with the carbon particles and fly ash discharged from the first cyclone separator 7 and enters the biomass gasifier 11 from the second feed inlet 34, and water vapor is added for gasification reaction. The main components of the syngas generated by gasification are H2, CO, CO2, CH4, H2O and a small amount of hydrocarbon compounds. At the same time, CaO and Fe2O3 particles are added to the biomass gasifier 11 from the third feed inlet 33 to participate in the gasification reaction together. On the one hand, the carbonation reaction of CaO with carbon dioxide is used to reduce the concentration of carbon dioxide in the syngas and promote the gasification reaction. On the other hand, the reaction of CaO with carbon dioxide is an exothermic reaction and can also provide a part of the heat energy for the gasification reaction; in the biomass gasifier 11, the Fe2O3 particles serve as both an oxygen carrier to provide oxygen for the gasification reaction and a heat carrier to provide the required heat for the gasification reaction.

[0042] The main reactions occurring in the biomass gasifier 11 are as follows:

[0043] (1) C + H2O → CO + H2

[0044] (2) CO + H2O → CO2 + H2

[0045] (3) CH4 + H2O → CO + 3H2

[0046] (4) 3Fe2O3 + CO → 2Fe3O4 + CO2

[0047] (5) 12Fe2O3 + CH4 → 8Fe3O4 + CO2 + 2H2O

[0048] (6) C + CO2 → 2CO

[0049] (7) C + 2H2 → CH4

[0050] (8)CaO + CO2 → CaCO3

[0051] The water vapor generated by the water - cooled wall 10 in the biomass gasifier 11 enters the biomass gasifier 11 through the water - vapor inlet 32 to participate in the gasification reaction on the one hand, and enters the activated - carbon preparation device 1 to participate in the activation treatment of biomass on the other hand. The syngas generated by biomass gasification is subjected to dust removal and purification treatment by the second cyclone separator 12, and then the unreacted biomass particles and fly ash are returned to the biomass gasifier 11 through the return feeder to participate in the gasification reaction; the purified syngas enters the catalytic reforming reactor 19 through the second induced draft fan 13 for catalytic reforming reaction. The residual carbon remaining after the gasification reaction, as well as Fe3O4 and CaCO3 generated by the gasification reaction, are discharged from the carbon outlet 31 at the bottom of the gasifier and enter the combustion reactor 15 through the second screw conveyor 30 from the fourth feed port 28 for combustion reaction. In the combustion reactor 15, the combustion reactions of Fe3O4 and residual carbon mainly occur, as well as the calcination of CaCO3, and the reaction temperature is 900 °C.

[0052] The main reactions occurring in the combustion reactor 15 are as follows:

[0053] (1) 4Fe3O4 + O2 → 6Fe2O3

[0054] (2) C + O2 → CO2

[0055] (3) CaCO3 → CaO + CO2

[0056] The high-temperature flue gas generated in the combustion reactor 15 carries Fe2O3 and CaO particles and enters the third cyclone separator 16 together for gas-solid separation. The separated Fe2O3 and CaO particles carry a large amount of heat and are transported as oxygen carriers and heat carriers to the biomass gasifier 11 through a pipeline via the third feed port 33 to participate in the gasification reaction. The high-temperature flue gas after dust removal and purification heats the air to 400 - 450 °C through the air preheater 18. A part of the high-temperature air preheated by the air preheater 18 enters the combustion reactor 15 through the air inlet 27 to participate in the combustion reaction, and the other part of the high-temperature air is connected to heat users to supply heat to the heat users. The combustible gas generated by the microwave reactor 5 and the gasification syngas generated by the biomass gasifier 11 are mixed and enter the catalytic reforming reactor 19 through the gas inlet 193. The water vapor generated in the upper header 14 of the second water-cooled wall of the combustion reactor 15 also enters the catalytic reforming reactor 19 through the gas inlet 193 to participate in the catalytic reforming reaction. A catalyst bed is arranged in the gas channel 191 of the catalytic reforming reactor 19, and the catalyst is a carbon-based catalyst loaded with Ni metal, and the carbon-based carrier is mainly prepared from biomass by the activated carbon preparation device 1. 95% of the solar radiation is completely absorbed by the absorption cavity 215 through the quartz glass window 213, and the alkali metal molten salt is heated to 400 - 500 °C. The high-temperature molten salt heated by the solar reactor 21 enters the high-temperature molten salt storage tank 22 through the high-temperature molten salt outlet 214. A part of the high-temperature molten salt is transported to the molten salt channel 192 of the catalytic reforming reactor 19 to provide the heat required for the steam catalytic reforming reaction of the syngas. The low-temperature molten salt after heat exchange is discharged from the low-temperature molten salt outlet 194, enters the low-temperature molten salt storage tank 20, and finally enters the molten salt heating cavity 211 through the low-temperature molten salt inlet 212 for reheating; another part of the high-temperature molten salt is transported to the activated carbon preparation device 1 to participate in the activation reaction of biomass. The alkali metal molten salt is a mixture of KNO3, NaNO3, and LiNO3. The syngas undergoes a steam catalytic reforming reaction in the catalytic reforming reactor, and the generated hydrogen-rich gas mainly consists of H2, CO2, and H2O, and the H2 concentration can reach 90 vol.%.

[0057] The main reactions occurring in the catalytic reforming reactor 19 are as follows:

[0058] (1) CH4 + H2O → CO + 3H2

[0059] (2) CO + H2O → CO2 + H2

[0060] (3) CnHm + 2nH2O → nCO2 + (4n + m) / 2H2

[0061] The hydrogen-rich gas generated by the catalytic reforming reaction is discharged from the hydrogen-rich gas outlet 196, and then enters the CO2 separation device 23 for separation and purification. The separated H2 and CO2 are stored by using the H2 storage tank and the CO2 storage tank respectively; the CO2 separation device 23 is a pressure swing adsorption purification device, and the adsorbent used in the pressure swing adsorption purification device comes from the activated carbon preparation device 1.

[0062] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A thermal hydrogen co-production system coupling solar energy and biomass energy, characterized in that, It includes an activated carbon preparation device (1), a microwave reactor (5), a biomass gasifier (11), a combustion reactor (15), an air preheater (18), a catalytic reforming reactor (19), a solar thermal energy storage system and a CO2 separation device (23); the biomass outlet (2) of the microwave reactor (5) is respectively connected to the feed inlets of the biomass gasifier (11) and the activated carbon preparation device (1), the carbon outlet (31) of the biomass gasifier (11) is connected to the combustion reactor (15), both the biomass gasifier (11) and the combustion reactor (15) are provided with water-cooled walls and water-cooled wall headers, the gas outlets of the microwave reactor (5) and the biomass gasifier (11) and the steam outlet of the water-cooled wall header of the combustion reactor (15) are connected to the gas inlet of the catalytic reforming reactor (19), the gas outlet of the catalytic reforming reactor (19) is connected to the CO2 separation device (23), and the CO2 separation device (23) is connected to a CO2 storage tank (24) and an H2 storage tank (25); an air preheater (18) is arranged at the flue gas outlet of the combustion reactor (15), and the high-temperature air outlet of the air preheater (18) is connected to the air inlet (27) of the combustion reactor (15) and a heat user; the heat storage medium inlet and outlet of the solar thermal energy storage system are connected to the heat storage medium inlet and outlet of the catalytic reforming reactor (19); the heat storage medium outlet of the solar thermal energy storage system is connected to the heat storage medium inlet of the activated carbon preparation device (1); the feed inlet of the biomass gasifier (11) serves as the inlet for CaO and the metal oxygen carrier; the steam outlet of the water-cooled wall header of the biomass gasifier (11) is respectively connected to the steam inlets of the biomass gasifier (11) and the activated carbon preparation device (1); the solar thermal energy storage system includes a low-temperature medium storage tank, a solar thermal device and a high-temperature medium storage tank connected in sequence, the inlet of the low-temperature medium storage tank serves as the heat storage medium inlet of the solar thermal energy storage system, the outlet of the high-temperature medium storage tank serves as the heat storage medium outlet of the solar thermal energy storage system, and the solar thermal device adopts a tower-type solar thermal device, a trough-type solar thermal device or a dish-type solar thermal device; the heat storage medium is an alkali metal molten salt; the solar thermal device adopts a solar reactor (21), the middle part of the solar reactor (21) is an absorption cavity (215), the absorption cavity (215) is open, and a heat storage medium heating cavity is arranged outside the absorption cavity (215); a quartz glass window (213) is arranged on the opening side of the absorption cavity (215), the surface of the absorption cavity (215) is coated with a coating with high solar absorptivity and low thermal emissivity, and the surface of the quartz glass window (213) is plated with a low-reflectivity coating for reducing heat loss; the main body of the catalytic reforming reactor (19) is cylindrical, the gas channel (191) of the catalytic reforming reactor (19) adopts a metal tube with external fin reinforcement, and the metal tube is spirally arranged inside the catalytic reforming reactor (19); a catalyst bed for the catalytic reforming reaction of syngas is arranged in the gas channel (191) of the catalytic reforming reactor (19).The gas flow direction in the catalytic reforming reactor (19) is opposite to the heat storage medium flow direction; the main body material of the catalytic reforming reactor (19) is austenitic stainless steel resistant to molten salt corrosion.

2. The solar energy-coupled biomass energy thermal hydrogen co-production system according to claim 1, wherein A stirring device is arranged at the top of the microwave reactor (5), and a first screw conveyor (3) is arranged at the inlet of the microwave reactor (5); the combustible gas outlet (6) of the microwave reactor (5) is connected to a first cyclone separator (7), the gas outlet of the biomass gasifier (11) is provided with a second cyclone separator (12), and a third cyclone separator (16) is arranged between the flue gas outlet of the combustion reactor (15) and the air preheater; the particulate matter outlet of the second cyclone separator (12) is connected to the biomass gasifier (11) through a return feeder, the particulate matter outlets of the first cyclone separator (7) and the third cyclone separator (16) are connected to the feed inlet of the biomass gasifier (11), and induced draft fans are arranged at the gas outlets of the first cyclone separator (7), the second cyclone separator (12) and the third cyclone separator (16).

3. The thermo-hydrogen co-production system coupling solar energy and biomass energy according to claim 1, wherein Both ends of the water wall are respectively connected to the upper header of the water wall and the lower header of the water wall. The lower header of the water wall is connected to the feed water system. A carbon outlet (31) is opened at the bottom of the biomass gasifier (11), and a fourth feed inlet (28) is opened in the combustion reactor (15). The carbon outlet (31) is connected to the fourth feed inlet (28) through a second screw conveyor (30).

4. The solar energy-coupled biomass thermal hydrogen co-production system according to claim 1, wherein The activated carbon preparation device (1) is a rotary kiln reactor. **5.** The solar energy-coupled biomass thermal hydrogen co-production system according to claim 1, wherein The CO2 separation device (23) is a pressure swing adsorption purification device or a membrane separation device; the activated carbon prepared in the activated carbon preparation device (1) is used as the adsorbent in the pressure swing adsorption purification device.

6. The thermo-hydrogen co-production system coupling solar energy and biomass energy according to claim 1, wherein The catalyst in the catalytic reforming reactor (19) is a carbon-based catalyst loaded with transition metals or their oxides, and the carbon-based carrier is the activated carbon prepared in the activated carbon preparation device (1).

7. A method for co-producing thermal hydrogen by coupling solar energy and biomass energy, characterized in that, Based on the solar-coupled biomass thermal hydrogen co-production system according to any one of claims 1-6, after the biomass raw material is heated and baked by microwave, a part of the solid product is used to prepare activated carbon, and another part of the solid product undergoes a biomass gasification reaction under the action of water vapor to produce gasification syngas; CaO and a metal oxygen carrier are added during the biomass gasification reaction; the coke remaining from the biomass gasification and the low-valent metal oxides or metal particles generated by the gasification are burned, and the high temperature generated by the combustion is used to calcine the CaCO3 generated by the gasification; the CaO and metal oxides generated by the combustion and the heat carried by them participate in the biomass gasification reaction again; the flue gas after combustion heats the air, and a part of the heated high-temperature air participates in the biomass gasification reaction, and the other part is supplied to heat users; the gaseous product, gasification syngas after the biomass raw material is heated and baked by microwave and the water vapor generated in the water wall undergo a catalytic reforming reaction under the heating condition of the heat storage medium to produce hydrogen-rich gas, and the H2 and CO2 in the hydrogen-rich gas product are separated and recovered; the heat storage medium is heated by a solar thermal device; a part of the water vapor generated in the water wall participates in the biomass gasification reaction again, and another part participates in the preparation of activated carbon. The heat storage medium is used for heating during the preparation of activated carbon, and the generated activated carbon is used as the catalyst carrier during the catalytic reforming reaction and the adsorbent during the separation of hydrogen-rich gas.

8. The method for co-producing thermal hydrogen by coupling solar energy and biomass energy according to claim 7, characterized in that, The gasification syngas is separated and purified. The generated particulate matter and fly ash are recycled and participate in the biomass gasification reaction again. The flue gas generated after the combustion of the coke remaining from biomass gasification is separated and purified. The generated particulate matter and fly ash are recycled to participate in the biomass gasification reaction, and the flue gas is used to heat air.

9. The method for co-producing thermal hydrogen by coupling solar energy and biomass energy according to claim 7, wherein The biomass gasification reaction is carried out in the biomass gasifier (11), and the combustion reaction is carried out in the combustion reactor (15). A carbon outlet (31) is opened at the bottom of the biomass gasifier (11), and a fourth feed inlet (28) is opened in the combustion reactor (15). The carbon outlet (31) is connected to the fourth feed inlet (28) through the second screw conveyor (30); the residual carbon remaining after the gasification reaction, as well as the low-valence metal oxides or metal particles and CaCO3 generated by the gasification reaction, are discharged from the carbon outlet (31) at the bottom of the gasifier and enter the combustion reactor (15) through the second screw conveyor (30) from the fourth feed inlet (28) for combustion reaction; water-cooled walls are provided on the biomass gasifier (11) and the combustion reactor (15). The water-cooled walls are connected with an upper header and a lower header. After the feed water enters the lower header and is heated by the water-cooled walls, the steam enters the upper header.

10. The method for co-producing heat and hydrogen by coupling solar energy with biomass energy according to claim 7, wherein The reaction temperature of the microwave reactor (5) is 200 - 300 °C; the reaction temperature of the activated carbon preparation device (1) is 300 - 400 °C; the reaction temperature of the biomass gasifier (11) is 600 - 700 °C; the reaction temperature of the combustion reactor (15) is 900 - 1000 °C, and the temperature of the catalytic reforming reactor (19) is 400 - 500 °C.

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