A method and system for producing hydrogen by a biomass combined process

Abstract

The present invention discloses a method and a system for producing hydrogen by a biomass combined process. The method first pre-treats biomass raw materials and then enters a carbonization reactor for carbonization. The solid product obtained by carbonization further enters a gasification reactor for gasification reaction. The gas-phase material obtained by the gasification reaction is subjected to a water-gas shift reaction and pressure swing adsorption treatment to obtain a hydrogen product. The present invention converts biomass into a high-value-added hydrogen product through a carbonization-gasification-purification and purification combined process, and has the advantages of simple process, high hydrogen production rate and purity, and high energy utilization rate.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass utilization, and particularly relates to a method and a system for producing hydrogen by using biomass as a raw material. Background Art

[0002] At present, fossil fuels still dominate the energy market, accounting for 87% of global energy consumption. However, due to the limited reserves of fossil fuels and a series of environmental problems caused by the combustion of fossil fuels, the development and utilization of clean energy and renewable energy have become one of the solutions. Among all alternative energy sources, hydrogen energy is the cleanest energy, and its combustion product is water, which can achieve "zero emissions" of pollutants. Secondly, the combustion calorific value of hydrogen is as high as 142.3 MJ / kg, which is 3 times that of gasoline with the same mass. Therefore, hydrogen, as a clean, efficient and renewable energy source, has good development prospects. Facing the current environmental and energy problems, hydrogen shows new utilization methods in more fields. For example, fuel cells have pushed the utilization of hydrogen to a new height, and hydrogen fuel cell vehicles are the most representative.

[0003] Currently, the main industrial hydrogen production methods include electrolysis of water, methanol steam reforming, catalytic steam conversion of heavy oil and natural gas, etc. The electrolysis of water method consumes a large amount of electric energy and has a high hydrogen production cost. Methanol steam reforming is currently the most economical hydrogen production method, but it requires a large amount of fossil fuels in the hydrogen production process, is not renewable, and produces a large amount of carbon dioxide. The method of using renewable biomass energy to produce hydrogen has received more and more attention, including biomass thermochemical hydrogen production, biological hydrogen production and electrolytic biomass hydrogen production, which have improved the hydrogen production rate and efficiency to a certain extent.

[0004] Patent CN1435368A discloses a method for producing hydrogen by catalytic pyrolysis of biomass. Using air or / steam as the working gas, and adopting animal and plant raw materials with a certain particle size as the biomass raw materials, the fluidized bed reactor includes a combustion zone, a catalytic gasification zone and a tar catalytic pyrolysis zone. The produced hydrogen-rich gas contains more than 70% hydrogen. After the hydrogen-rich gas is removed of dust by a cyclone separator, it is purified and refined by a fixed bed tar cracker. However, this process has defects such as high gasification temperature, high energy consumption, high requirements for equipment, expensive alkali metal catalysts and nickel-based catalysts, and harsh usage conditions. Patent CN105692551A continuously feeds biomass and steam into a fluidized bed reactor for rapid pyrolysis at 600 °C. The generated pyrolysis gas and biomass char enter a entrained flow bed reactor together with steam for the synchronous gasification reaction of the pyrolysis gas and biomass char. The gas coming out of the entrained flow bed reactor undergoes a catalytic reforming reaction to generate hydrogen-rich gas. The catalytic reforming uses Co and Cu-based modified catalysts, which has the disadvantages of harsh reaction conditions for biomass steam gasification and expensive reforming catalysts. Patent CN 104194834 A provides a biomass chemical looping hydrogen production device that uses NiFe2O4 oxygen carrier for chemical looping hydrogen production, which has problems such as expensive oxygen carrier, cyclic service life and reaction activity, etc.

[0005] In summary, in order to further improve the utilization rate of biomass and the hydrogen production rate, and obtain higher economic benefits, it is necessary to innovate on the basis of the existing technology to improve the rate and efficiency of hydrogen production. The development of new thermochemical conversion hydrogen production processes, inexpensive catalysts, and the reduction of energy consumption in hydrogen production processes are still the key points and difficulties in research. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method and system for producing hydrogen by a biomass carbonization-gasification-purification and refining combined process. By the carbonization-gasification-purification and refining combined process, biomass is converted into high-value hydrogen products, which has the advantages of simple process, high hydrogen production rate and purity, and high energy utilization rate.

[0007] To achieve the above object, the first aspect of the present invention provides a method for producing hydrogen by a biomass combined process in the first embodiment, including the following steps:

[0008] (1) Under contact conditions, mix the biomass raw materials with crude wood vinegar liquid, and then obtain pretreated biomass raw materials after drying.

[0009] (2) The pretreated biomass raw materials obtained in step (1) enter a carbonization reactor for carbonization reaction, and after the reaction is completed, solid products and gas products are obtained.

[0010] (3) Under contact conditions, mix the solid product obtained from the carbonization reactor in step (2), the iron-containing oxide, and the potassium-containing compound. After mixing evenly, feed them into the gasification reactor for activation, and then carry out steam gasification reaction in the presence of steam;

[0011] (4) The gas-phase stream obtained from the gasification reaction in step (3) is further subjected to a water-gas shift reaction and pressure swing adsorption treatment to obtain a hydrogen product.

[0012] The second aspect of the present invention provides a method for producing hydrogen by a biomass combination process in a second embodiment, which includes the following steps:

[0013] (1) Under contact conditions, mix the biomass raw material, activated carbon, and crude wood vinegar liquid, and then dry them to obtain a pretreated biomass raw material;

[0014] (2) The pretreated biomass raw material obtained in step (1) enters a carbonization reactor for carbonization reaction, and after the reaction is completed, a solid product and a gas product are obtained;

[0015] (3) Under contact conditions, mix the solid product obtained from the carbonization reactor in step (2), the iron-containing oxide, and the potassium-containing compound. After mixing evenly, feed them into the gasification reactor for activation, and then carry out steam gasification reaction in the presence of steam;

[0016] (4) The gas-phase stream obtained from the gasification reaction in step (3) is further subjected to a water-gas shift reaction and pressure swing adsorption treatment to obtain a hydrogen product.

[0017] Further, in the method for producing hydrogen by the above biomass combination process, the biomass raw material is any biomass containing lignocellulose such as forestry residues or agricultural residues. More specifically, it can be selected from one or more of straw, rice husk, wheat straw, wood block, leaf, and branch. The maximum dimension of the biomass raw material in the largest direction does not exceed 30 mm, preferably 1 - 25 mm, and the shape is not limited and can be any shape selected from sheet, round, cylinder, cone, square, irregular shape, etc.

[0018] Further, in the method for producing hydrogen by the above biomass combined process, the crude wood vinegar liquid comes from the biomass pyrolysis or dry distillation process, generally including wood vinegar liquid and wood tar. The content of wood vinegar liquid in the crude wood vinegar liquid is 60-70 wt%. After the crude wood vinegar liquid is obtained from the biomass pyrolysis or dry distillation process, it can be directly used without any separation process. The plant organic composite substances such as acids, alcohols, ketones, aldehydes, etc. rich in the wood vinegar liquid all contain a certain amount of organic functional groups. By mixing it with the biomass raw material for pretreatment, on the one hand, the cellulose, hemicellulose and lignin in the biomass can be swollen by water absorption, the complete infiltration of water-soluble substances can be achieved, and the interaction force between different components of the biomass can be weakened, which is more conducive to the carbonization process. On the other hand, the wood tar can be evenly dispersed on the surface of the biomass raw material through the impregnation mixing contact process.

[0019] Further, in the method for producing hydrogen by the above biomass combined process, the mass ratio of the biomass raw material to the crude wood vinegar liquid in step (1) is 1:1-1:6.

[0020] Further, in the method for producing hydrogen by the above biomass combined process, the mass ratio of the biomass raw material to the activated carbon in step (1) is 1:0.3-1:2.

[0021] Further, in the method for producing hydrogen by the above biomass combined process, the activated carbon in step (1) is one or more of biomass-based activated carbon, pitch-based activated carbon, and petroleum coke-based activated carbon, preferably pitch-based activated carbon and / or petroleum coke-based activated carbon with a dense structure. The petroleum coke-based activated carbon refers to the activated carbon with rich pore structure obtained from petroleum coke as the raw material through physical and / or chemical activation processes. Further preferably, the petroleum coke-based activated carbon is the activated carbon product obtained by activating the petroleum coke generated in the coking process, with a specific surface area of 1200-3000 m 2 / g, the pore diameter is generally 0.5-8 nm, and the mesopore ratio is 10%-30%. For those skilled in the art, the physical and / or activation processes of the petroleum coke are well-known and can be selected from the existing methods according to needs.

[0022] Further, in the method for producing hydrogen by the above biomass combined process, activated carbon is introduced during the biomass pyrolysis carbonization process. The abundant pore structure and large pore volume of the activated carbon can achieve in-situ capture of the tar components pyrolyzed, especially the heavy tar components rich in polycyclic aromatic hydrocarbons. This not only reduces the tar content in the pyrolysis gas, but also provides sufficient condensation reaction space for the heavy tar components, deposits amorphous coke on the inner surface of the activated carbon, increases the carbonization yield. At the same time, during the biochar gasification stage in the gasification reactor, sufficient space is provided for the amorphous biochar on the inner surface of the activated carbon to react with water vapor, improving the gasification reaction conversion rate of the biochar and the syngas yield. The activated carbon basically does not participate in the reaction during the biomass pyrolysis process and undergoes a small amount of reaction during the biochar gasification stage, but has no impact on the properties of the syngas product.

[0023] Further, in the method for producing hydrogen by the above biomass combined process, the drying temperature in step (1) is 40 - 100 °C, and it is further preferably dried under vacuum conditions.

[0024] Further, in the method for producing hydrogen by the above biomass combined process, the reaction conditions of the carbonization reactor in step (2) are as follows: the carbonization reaction temperature is 120 - 550 °C, preferably 200 - 500 °C; more preferably, the carbonization reaction is carried out in two stages. The carbonization reaction temperature in the first stage is 120 - 300 °C. At the relatively low carbonization temperature in the first stage, the reaction is mainly dominated by the interaction between the biomass and the wood vinegar liquid, promoting the interaction between the wood vinegar liquid and the cellulose, lignin, and hemicellulose in the biomass. The plant organic composite substances such as acids, alcohols, ketones, and aldehydes in the wood vinegar liquid, with the participation of activated carbon, repeatedly interact with the cellulose, hemicellulose, and lignin in the biomass to achieve the preliminary carbonization of the biomass. During this process, the generation amounts of gas and tar are less, and more carbon precursors are reserved for the second-stage carbonization. The carbonization reaction temperature in the second stage is 350 - 550 °C. At the relatively high reaction temperature, the carbonization process of the biomass proceeds rapidly, and at the same time, a certain amount of gas and tar are generated. When the tar escapes carried by the gas, it encounters the activated carbon with a rich pore structure. The rich pore structure of the activated carbon reduces the escape rate of the tar molecules. On the one hand, it provides a space for the secondary cracking of the light tar components generated during the wood vinegar liquid and biomass carbonization process. On the other hand, it increases the residence time of the heavier tar macromolecules. The tar molecules and carbon deposition precursors deep inside the activated carbon particles are difficult to diffuse and transform in time, and directly undergo coke carbonization in the micropore channels, increasing the yield of the biomass carbon. At the same time, the amorphous biochar generated inside the activated carbon has a high reaction activity and is easy to undergo gasification reactions during the subsequent steam gasification process, improving the syngas yield and selectivity.

[0025] Further, in the method for producing hydrogen by the above biomass combined process, the solid products obtained from the carbonization reactor include biochar and activated carbon.

[0026] Further, in the method for producing hydrogen by the above biomass combined process, the iron oxide can be selected from one or more of magnetite, ferric oxide, and ferrous oxide.

[0027] Further, in the method for producing hydrogen by the above biomass combined process, the potassium-containing compound can be selected from one or more of potassium sulfate, potassium carbonate, potassium chloride, potassium nitrate, potassium tartrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium iodide, potassium bromide, potassium hydroxide, and potassium fluoride, and preferably one or more of potassium sulfate, potassium carbonate, potassium chloride, potassium nitrate, potassium tartrate, potassium iodide, potassium bromide, and potassium hydroxide.

[0028] Further, in the method for producing hydrogen by the above biomass combined process, the mass ratio of the biomass to the iron oxide is 60:1 to 10:1.

[0029] Further, in the method for producing hydrogen by the above biomass combined process, the mass ratio of the biomass to the potassium-containing compound is 50:1 to 10:1.

[0030] Further, in the method for producing hydrogen by the above biomass combined process, the mixing process of the solid products obtained after the reaction in the carbonization reactor with the iron oxide and the potassium-containing compound is carried out by the dry mixing method. The dry mixing method means that the solid products obtained after the reaction in the carbonization reactor are advanced and turned up and down in a screw propeller with the iron oxide and the potassium-containing compound before entering the gasification reactor to achieve uniform mixing, and they are jointly used as the feed for the gasification reactor.

[0031] Further, in the method for producing hydrogen by the above biomass combined process, the activation carried out in the gasification reactor in step (3) is carried out in a reducing atmosphere. The activation temperature is 450 to 750 °C, preferably 500 to 700 °C; the steam flow rate is 0.05 to 0.8 mL / min. The reducing atmosphere is a hydrogen-containing gas, specifically it can be hydrogen or a mixture of hydrogen and a carrier gas. The carrier gas is one or more of helium and nitrogen, and the volume fraction of hydrogen in the mixture is 5% to 50%.

[0032] Further, in the method for producing hydrogen from biomass above, the gasification reaction conditions in step (3) are: the reaction temperature is 700 to 950 °C, preferably 750 to 900 °C, and the steam flow rate is 0.05 to 0.8 mL / min.

[0033] Further, in the method for producing hydrogen by the above biomass combined process, the water-gas shift reaction in step (4) can adopt the existing water-gas shift process in the art. For example, a copper-based low-temperature shift catalyst B208 can be used, with a composition of CuO / ZnO / Al2O3 (mass fraction of CuO is 38%, mass fraction of ZnO is 40%, and mass fraction of Al2O3 is 8%), and the catalyst particle size is 20 - 40 mesh. The gas-phase feed stream obtained from the gasification reactor in step (3) enters the water-gas shift device and reacts with the water vapor simultaneously entering the device. Generally, the conditions for the water-gas shift reaction are: reaction temperature 250 - 300 °C, volume flow ratio of water vapor to the gas-phase feed stream is 0.5 - 0.9, and the gasification gas space velocity is 1500 - 2500 h -1 .

[0034] Further, in the method for producing hydrogen by the above biomass combined process, the pressure swing adsorption in step (4) is carried out using an existing pressure swing adsorption device in the art. The outlet gas of the water-gas shift device is sent into the adsorbent bed layer of the pressure swing adsorption device. The adsorbent can be a graded adsorbent composed of activated carbon, molecular sieve, silica gel, and activated alumina in a certain proportion. Through pressure transformation, high-purity hydrogen flows out from the outlet through the adsorption layer. The pressure swing adsorption system is depressurized, desorbed, replaced, and evacuated to -0.08 MPa for treatment. After desorption treatment, it is pressurized to regenerate the pressure swing adsorption system, and the cycle treatment is carried out in sequence. The operating conditions for the pressure swing adsorption are: pressure is 1.5 - 4 MPa, and temperature is 20 - 30 °C.

[0035] Further, in the method for producing hydrogen by the above biomass combined process, the gas product obtained from the carbonization reaction in step (2) from the carbonization reactor is a volatile gas, including combustible gases, volatile tar components, etc. generated during the biomass pyrolysis and carbonization processes, which escape from the carbonization reactor in gaseous form. Furthermore, the gas product from the carbonization reactor can enter the burner for full combustion (meaning the combustion products are only carbon dioxide and water). The heat generated by the combustion is supplied to the steam generator, carbonization reactor, and gasification reactor for use, preferentially supplied to the steam generator for use, and the excess heat is used to assist the carbonization reactor and gasification reactor.

[0036] The third aspect of the present invention provides a system for producing hydrogen by a biomass combined process, including the following:[[]]

[0037] A mixer, which is used to receive and mix biomass raw materials, crude wood vinegar liquid, and optionally activated carbon,[[]]

[0038] A dryer, which is used to receive and dry the materials after being mixed evenly from the mixer, and the pre-treated biomass raw materials are obtained after drying;[[]]

[0039] A carbonization reactor, which is used to receive the pretreated biomass raw material obtained from a dryer. The pretreated biomass raw material enters the carbonization reactor for carbonization reaction, and after the reaction, solid products and gas products are obtained.

[0040] An air gasification reactor, which is used to receive the solid products, iron oxides, and potassium compounds obtained from the carbonization reactor. After the solid products, iron oxides, and potassium compounds obtained from the carbonization reactor are mixed evenly, activation is carried out, and then they are contacted with water vapor for reaction. After the reaction, a gas-phase stream is obtained.

[0041] A water gas shift reactor, which is used to receive the gas-phase stream obtained after the reaction in the air gasification reactor.

[0042] A pressure swing adsorption reactor, which is used to receive the gas-phase stream obtained after being treated in the water gas shift reactor, and hydrogen is obtained after treatment.

[0043] Furthermore, in the above hydrogen production system by the biomass combined process, the dryer can adopt any one of the existing equipment in the art that can achieve the drying function, specifically, it can be any one or several of a blast drying oven, a vacuum drying oven, a hot air circulation oven, etc.

[0044] Furthermore, in the above hydrogen production system by the biomass combined process, the carbonization reactor can adopt any one of the existing carbonization reactors in the art, specifically, it can adopt any one of a biomass microwave vertical fixed-bed reactor, a biomass screw propulsion carbonization reactor, a biomass rotary furnace carbonization reactor, etc.

[0045] Furthermore, in the above hydrogen production system by the biomass combined process, the air gasification reactor can adopt any one of a microwave vertical fixed-bed gasification reactor, a microwave fluidized-bed gasification reactor, an electrically heated vertical fixed-bed reactor, etc.

[0046] Furthermore, in the above hydrogen production system by the biomass combined process, a steam generator is included, which is used to generate water vapor.

[0047] Furthermore, in the above hydrogen production system by the biomass combined process, a burner is included. The gas products from the carbonization reactor enter the burner to burn fully (the full combustion generally means that the combustion products are only carbon dioxide and water). The heat generated by the gas combustion can be supplied to the steam generator, the carbonization reactor, and the air gasification reactor for use. Preferably, it is first supplied to the steam generator for use, and the excess heat is used to assist the carbonization reactor and the air gasification reactor.

[0048] Furthermore, in the system for producing hydrogen by the above biomass combination process, the water-gas shift reactor and the pressure swing adsorption reactor can be any of the existing devices in the art, and those skilled in the art can select a water-gas shift reactor and a pressure swing adsorption reactor suitable for the technical solution of the present application from the existing devices according to actual needs.

[0049] Compared with the prior art, the beneficial technical effects of the method and system for producing hydrogen by the biomass combination process of the present invention are as follows:

[0050] (1) In the method for producing hydrogen from biomass of the present invention, the biomass raw material is converted into a hydrogen product through a combined treatment process, which has the advantages of simple process, high hydrogen production rate, and high energy utilization rate.

[0051] (2) The method of the present invention pre-treats the biomass raw material with the crude wood vinegar obtained from biomass pyrolysis or dry distillation, which not only finds a suitable utilization way for the low-value-added crude wood vinegar, but also effectively promotes the biomass carbonization process, and at the same time does not affect the product properties.

[0052] (3) In the present invention, through the effective coordination of the two-stage carbonization process adjustment with wood vinegar and petroleum coke-based activated carbon, the in-situ capture and conversion of tar components are realized, the coke yield is significantly improved, and at the same time, sufficient space is provided for the amorphous bio-coke on the inner surface of the activated carbon to react with water vapor during the bio-coke gasification stage, realizing the maximization of the gasification reaction conversion rate and hydrogen yield of bio-coke.

[0053] (4) The catalytic materials used in the present invention are widely sourced, can be obtained from natural ores and seawater, are inexpensive, greatly reduce the catalytic cost of bio-coke steam gasification, can be recycled by water-soluble method or used as disposable catalysts. Two low-cost catalyst raw materials, iron-based oxides and potassium salts, have a strong interaction during the catalyst activation process, forming an intermediate substance that can improve the reaction activity of potassium salts and fix potassium at the same time, which can significantly improve the steam gasification reaction activity, reduce the gasification reaction temperature, and also play a good role in the fixation of alkali metals, greatly reducing the volatilization amount of alkali metals.

[0054] (5) In the method for producing hydrogen from biomass of the present invention, the volatile components generated in the carbonization reactor are sent to the burner for combustion in a high-temperature state, and the tar components are burned together with the combustible gas in a gaseous state, avoiding environmental pollution caused by tar emissions and gas purification, preventing pipeline blockage caused by tar condensation, and solving the oil-gas separation problem, greatly simplifying the reaction steps. Through the regenerative heat exchanger, the huge heat generated by the combustion of volatile components is supplied to the steam generator, the carbonization reactor, and the gasification reactor, providing heat and reaction temperature for the hydrogen production reaction, assisting the energy supply of the whole process, and ensuring the stable operation of the reaction. Brief Description of the Drawings

[0055] Figure 1 This is a schematic diagram of the method and system for producing hydrogen by the biomass combination process of the present invention. Detailed Embodiments

[0056] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "comprises" or "including" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0057] In this document, for convenience of description, spatial relative terms such as "below", "beneath", "under", "above", "over", "on" etc. may be used to describe the relationship between one element or feature and another element or feature in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations of the object in use or operation in addition to the orientation depicted in the figures. For example, if the object in the figure is flipped, an element described as "below" or "under" another element or feature will be oriented "above" the said element or feature. Thus, the exemplary term "below" can encompass both the below and above directions. The object can also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used herein should be interpreted accordingly.

[0058] In this document, terms such as "first", "second" etc. are used to distinguish two different elements or parts, and are not used to define a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second" etc. can also be interchanged with each other.

[0059] In this document, all numerical values of parameters (e.g., quantity or condition) should be understood to be modified by the term "about" in all cases, whether or not "about" actually appears before the numerical value.

[0060] In this document, the specific surface area and pore size distribution curve of the sample are obtained from the nitrogen adsorption - desorption curve on a Micromeritics ASAP 2020 type adsorption instrument. The operating temperature is -196°C (liquid nitrogen temperature). The sample is pre - dehydrated at 300°C under nitrogen protection before testing. The specific surface area and pore size distribution are calculated by the BET method and the DFT method respectively.

[0061] Example 1

[0062] Weigh 100 g of petroleum coke, mix the petroleum coke evenly with 280 g of potassium hydroxide, activate it at 800 °C for 40 min under a nitrogen atmosphere, cool it to room temperature, wash the product with dilute hydrochloric acid and deionized water in sequence until it is neutral, and dry it at 105 °C for 10 h in a forced-air drying oven to obtain petroleum coke-based activated carbon. The specific surface area is measured to be 1896 m 2 / g, the mesopore ratio is 18%, and the pore size range is 0.5 - 8 nm.

[0063] Example 2

[0064] Weigh 100 g of high softening point pitch, mix the petroleum coke evenly with 280 g of potassium hydroxide, activate it at 850 °C for 60 min under a nitrogen atmosphere, cool it to room temperature, wash the product with dilute hydrochloric acid and deionized water in sequence until it is neutral, and dry it at 105 °C for 10 h in a forced-air drying oven to obtain pitch-based activated carbon. The specific surface area is measured to be 2014 m 2 / g, the mesopore ratio is 14%, and the pore size range is 0.5 - 15 nm.

[0065] Example 3

[0066] Weigh 100 g of coconut shell charring material, activate the coconut shell at 800 °C under a nitrogen-steam atmosphere, the steam flux is 0.1 mL / min, activate for 5 h, cool it to room temperature, and dry it at 105 °C for 4 h in a forced-air drying oven to obtain bio-based activated carbon. The specific surface area is measured to be 1056 m 2 / g, the mesopore ratio is 19%, and the pore size range is 0.8 - 50 nm.

[0067] Example 4

[0068] Weigh 30.6 g of Picea koraiensis crushed material, add 30.6 g of crude wood vinegar, 61.2 g of deionized water, and 9.18 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 40 °C under vacuum for 10 h to obtain the pretreated biomass raw material.

[0069] The pretreated biomass raw material is added to the biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 120 °C, and the reaction time is 60 min. The temperature of the second-stage carbonization reaction is 550 °C, and the reaction time is 50 min. The solid product of the carbonization reaction is mixed evenly with 0.72 g of Fe2O3 and 1.38 g of K2SO4 in a screw feeder, and the catalyst is activated at 450 °C under a hydrogen atmosphere for 25 min. Then, steam is introduced for gasification. The reaction conditions are: temperature 800 °C, atmospheric pressure, and the steam flux is 0.3 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 52.2%. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas at the outlet of the water-gas shift reactor reaches 63.1%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 99%. The hydrogen production rate of biomass in the whole process is 113.5 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, ensuring the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0070] Example 5

[0071] Weigh 35.2 g of crushed hazelwood, add 211.2 g of crude wood vinegar and 70.4 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 100 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0072] The pretreated biomass raw material is added to the biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 300 °C, and the reaction lasts for 30 min. The second-stage carbonization reaction is at 350 °C for 50 min. The solid product of the carbonization reaction is mixed evenly with 0.64 g of Fe2O3 and 1.48 g of KCl in a spiral feeder, and the catalyst is activated at 750 °C for 20 min under a nitrogen-hydrogen mixed atmosphere (hydrogen volume fraction is 30%); steam is introduced for gasification reaction, and the reaction conditions are: temperature 950 °C, atmospheric pressure, and the steam flux is 0.05 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 51.7%. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 63.5%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 99%. The hydrogen production rate of biomass in the whole process is 126.1 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to the combustion furnace for combustion at a high temperature. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0073] Example 6

[0074] Weigh 39.4 g of crushed willow wood, add 120.4 g of crude wood vinegar liquid and 39.4 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 60 °C under vacuum for 20 h to obtain the pretreated biomass raw material.

[0075] The pretreated biomass raw material is added to a biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 180 °C, and the reaction time is 40 min. The temperature of the second-stage carbonization reaction is 400 °C, and the reaction time is 50 min. The solid product of the carbonization reaction is mixed evenly with 3.94 g of Fe3O4 and 2.41 g of KBr in a screw feeder, and is activated at 650 °C for 45 min under a nitrogen-hydrogen mixed atmosphere (the volume fraction of hydrogen is 15%); steam is introduced for gasification, and the reaction conditions are: temperature 700 °C, atmospheric pressure, and the steam flux is 0.8 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 52.5%. The gasification gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 62.8%. Then, the hydrogen concentration can be increased to 99% through pressure swing adsorption. The hydrogen production rate of biomass in the whole process is 134.7 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0076] Example 7

[0077] Weigh 40.3 g of fir powder, add 80.6 g of crude wood vinegar, 40.3 g of deionized water, and 24.2 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, stand for impregnation for 6 h, and dry at 80 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0078] The pretreated biomass raw material is added into a biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 280 °C, and the reaction lasts for 20 min. The second-stage carbonization reaction is at 450 °C for 50 min. The solid product of the carbonization reaction is mixed evenly with 0.67 g of Fe2O3 and 0.81 g of potassium tartrate in a screw feeder, and the catalyst is activated at 550 °C under a helium-hydrogen mixed atmosphere (the volume fraction of hydrogen is 50%) for 45 min. Water vapor is introduced for gasification reaction. The reaction conditions are: temperature 850 °C, atmospheric pressure, and the water vapor flux is 0.55 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 56.8%. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 61.4%. Then, the hydrogen concentration can be increased to 97% through pressure swing adsorption. The hydrogen production rate of biomass in the whole process is 113.4 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion in a high-temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0079] Example 8

[0080] Weigh 38.8 g of crushed Pinus sylvestris var. mongolica twigs, add 110.7 g of crude wood vinegar and 27.2 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0081] The pretreated biomass raw material is added to a biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 230 °C, and the reaction lasts for 40 min. The second-stage carbonization reaction is carried out at 500 °C for 50 min. The solid product of the carbonization reaction is mixed evenly with 1.22 g of Fe3O4 and 3.88 g of KNO3 in a screw feeder and then enters a biochar gasification reactor. Catalyst activation is carried out at 400 °C for 25 min under a nitrogen-hydrogen mixed atmosphere (hydrogen volume fraction is 5%). Steam is introduced for gasification reaction. The reaction conditions are: temperature 800 °C, atmospheric pressure, and steam flux 0.4 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 52.9%. The gasification gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas. The volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 63.6%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 99%. The hydrogen production rate of biomass in the whole process is 135.4 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, ensuring the energy supply for the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is needed to ensure the stable operation of the reaction.

[0082] Example 9

[0083] Weigh 36.3 g of crushed Pinus sylvestris var. mongolica trunk, add 72.6 g of crude wood vinegar and 40.2 g of the biomass-based activated carbon obtained in Example 3, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0084] The pretreated biomass raw material is added to a biomass carbonization reactor for reaction. The carbonization reaction temperature is 440 °C, and the reaction lasts for 40 min. The solid product of the carbonization reaction is mixed evenly with 0.83 g of ferrous oxide FeO and 1.91 g of KBr in a spiral feeder and then enters a biochar gasification reactor. It is activated at 500 °C for 35 min under a nitrogen-hydrogen mixed atmosphere (hydrogen volume fraction is 5%). Steam is introduced for the gasification reaction, and the reaction conditions are: temperature 750 °C, atmospheric pressure, and steam flux 0.4 mL / min. The gas composition at the outlet of the gasification reactor is 54.1% in volume fraction of H2. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the H2 volume fraction in the gas from the outlet of the water-gas shift reactor reaches 62.3%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 98%. The hydrogen production rate of biomass in the whole process is 119.7 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion in a high-temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is needed to ensure the stable operation of the reaction.

[0085] Comparative Example 1

[0086] Weigh 38.8 g of crushed Pinus sylvestris var. mongolica twigs and branches, add 110.7 g of water and 27.2 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0087] The pretreated biomass raw material is added to the biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 230 °C, and the reaction lasts for 40 min. The temperature of the second-stage carbonization reaction is 500 °C, and the reaction lasts for 50 min. The solid product of the carbonization reaction is mixed evenly with 1.22 g of Fe3O4 and 3.88 g of KNO3 in a screw feeder and then enters the biochar gasification reactor. The catalyst is activated at 400 °C for 25 min under a nitrogen-hydrogen mixed atmosphere (the volume fraction of hydrogen is 5%); steam is introduced for gasification reaction. The reaction conditions are: temperature 850 °C, atmospheric pressure, and the steam flux is 0.4 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 51.5%. The hydrogen concentration in the gas is further increased through a water-gas shift reactor. The volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 62.7%. Then, the hydrogen concentration can be increased to 99% through pressure swing adsorption. The hydrogen production rate of biomass in the whole process is 112.6 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to the combustion furnace for combustion in a high-temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0088] Comparative Example 2 The solid product of the carbonization reaction is mixed evenly with 1.22 g of Fe3O4 and 3.88 g of KNO3 in a screw feeder and then enters the biochar gasification reactor. The catalyst is activated at 400 °C for 25 min under a nitrogen-hydrogen mixed atmosphere (the volume fraction of hydrogen is 5%); steam is introduced for gasification reaction. The reaction conditions are: temperature 850 °C, atmospheric pressure, and the steam flux is 0.4 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 51.5%. The hydrogen concentration in the gas is further increased through a water-gas shift reactor. The volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 62.7%. Then, the hydrogen concentration can be increased to 99% through pressure swing adsorption. The hydrogen production rate of biomass in the whole process is 112.6 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to the combustion furnace for combustion in a high-temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0089] Weigh 30.5 g of crushed corn straw, add 88.4 g of wood vinegar solution and 46.1 g of the petroleum coke-based activated carbon obtained in Example 1, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0090] The pretreated biomass raw material is added to a biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 230 °C, and the reaction lasts for 40 min. The temperature of the second-stage carbonization reaction is 500 °C, and the reaction lasts for 50 min. The solid product of the carbonization reaction is mixed evenly with 2.56 g of KNO3 in a spiral feeder and then enters a biochar gasification reactor. Steam is introduced for gasification reaction. The reaction conditions are as follows: temperature 800 °C, atmospheric pressure, and the steam flux is 0.4 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 56.8%. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas. The volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 63.4%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 99%. The hydrogen production rate of biomass in the whole process is 108.8 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion in a high-temperature state. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is required to ensure the stable operation of the reaction.

[0091] Comparative Example 3

[0092] Weigh 31.6 g of crushed bamboo willow, add 94.8 g of wood vinegar liquid and 56.1 g of the pitch-based activated carbon obtained in Example 2, stir and mix evenly, let it stand for impregnation for 6 h, and dry it at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0093] The pretreated biomass raw material is added to the biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 230 °C, and the reaction lasts for 40 min. The second-stage carbonization reaction is at 500 °C for 50 min. The solid product of the carbonization reaction is mixed evenly with 1.22 g of Fe3O4 in a screw feeder and then enters the biochar gasification reactor. It is activated at 400 °C for 25 min under a nitrogen-hydrogen mixed atmosphere (hydrogen volume fraction is 5%). Steam is introduced for gasification reaction. The reaction conditions are: temperature 750 °C, atmospheric pressure, and steam flux 0.25 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 57.4%. The gasified gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 62.3%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 97%. The hydrogen production rate of biomass in the whole process is 103.7 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is needed to ensure the stable operation of the reaction.

[0094] Comparative Example 4

[0095] Weigh 36.1 g of crushed willow wood, add 105.7 g of crude wood vinegar liquid and 37.2 g of existing petroleum coke-based activated carbon (specific surface area 1244 m 2 / g, mesopore rate 2%, pore size mainly micropores below 1 nm) and stir to mix evenly. Let it stand for impregnation for 6 h and dry at 70 °C under vacuum for 8 h to obtain the pretreated biomass raw material.

[0096] The pretreated biomass raw materials are added to a biomass carbonization reactor for reaction. The temperature of the first-stage carbonization reaction is 230 °C, and the reaction lasts for 40 min. The second-stage carbonization reaction is at 500 °C for 50 min. The solid product of the carbonization reaction is mixed evenly with 1.22 g of Fe3O4 and 3.88 g of KNO3 in a spiral feeder and then enters a biochar gasification reactor. It is activated at 450 °C for 25 min under a nitrogen-hydrogen mixed atmosphere (the volume fraction of hydrogen is 5%). Steam is introduced for gasification reaction. The reaction conditions are: temperature 800 °C, atmospheric pressure, and the steam flux is 0.35 mL / min. The gas composition at the outlet of the gasification reactor is that the volume fraction of H2 is 54.1%. The gasification gas passes through a water-gas shift reactor to further increase the hydrogen concentration in the gas, and the volume fraction of H2 in the gas from the outlet of the water-gas shift reactor reaches 62.6%. Then, through pressure swing adsorption, the hydrogen concentration can be increased to 98%. The hydrogen production rate of biomass in the whole process is 122.6 g of hydrogen / kg of biomass. At the same time, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing guarantee for the energy supply of the whole process, greatly reducing the energy consumption of the process itself, and only a small amount of auxiliary heating is needed to ensure the stable operation of the reaction. It can be seen from Examples 3 to 7 and Comparative Examples 1 to 4 that in the biomass carbonization process of the present invention, the maximum yield of biochar is achieved by means of impregnation with crude wood vinegar, addition of petroleum coke-based activated carbon, temperature adjustment, etc. The iron-based oxide and potassium salt are effectively coupled and have a strong interaction during the catalyst activation process, forming an intermediate substance that can improve the reaction activity of the potassium salt and fix potassium at the same time, which can significantly improve the steam gasification reaction activity, reduce the gasification reaction temperature, and at the same time, also plays a good role in the fixation of alkali metals, greatly reducing the volatilization amount of alkali metals.

[0097] In the present invention, the volatile components generated in the biomass carbonization reactor are sent to a combustion furnace for combustion at a high temperature. The tar components are burned together with combustible gases in a gaseous state, avoiding environmental pollution caused by tar emissions and gas purification, preventing pipeline blockage caused by tar condensation, and more importantly, avoiding the complex problem of oil-gas separation, greatly simplifying the reaction steps. Through a regenerative heat exchanger, the huge heat generated by the combustion of the volatile components is supplied to the steam generator, the biomass carbonization reactor, and the biochar gasification reactor, providing heat and reaction temperature for the synthesis gas production reaction, providing most of the energy supply for the whole process, ensuring the stable operation of the reaction, and greatly reducing the energy consumption of the reaction. Therefore, a method and system for producing synthesis gas from biomass disclosed in the present invention have the advantages of simple process, high synthesis gas yield, and high energy utilization rate, and have wide promotion value.

Claims

1. A method for producing hydrogen using a biomass combined process, comprising the following steps: (1) mixing the biomass raw material with the crude wood vinegar under contact conditions, and then drying the mixture to obtain a pretreated biomass raw material; Biomass feedstock is any biomass containing lignocellulose, and crude wood vinegar comes from the biomass pyrolysis process, including wood vinegar and wood tar; (2) The pretreated biomass raw material obtained in step (1) enters a carbonization reactor for carbonization reaction, and after the reaction is completed, a solid product and a gaseous product are obtained; the carbonization reaction is carried out in two stages, the carbonization reaction temperature of the first stage is 120-300°C, and the carbonization reaction temperature of the second stage is 350-550°C; (3) under contact conditions, mixing the solid product obtained in the carbonization reactor of step (2), the iron-containing oxide, and the potassium-containing compound, and after uniform mixing, entering the gasification reactor for activation, and after activation, performing a steam gasification reaction in the presence of water vapor; (4) The gas phase stream obtained by the gasification reaction in step (3) is further subjected to a water vapor shift reaction and pressure swing adsorption treatment to obtain a hydrogen product.

2. A method for producing hydrogen using a biomass combined process, comprising the following steps: (1) mixing a biomass raw material, activated carbon, and crude wood vinegar under contact conditions, and then drying the mixture to obtain a pretreated biomass raw material; Biomass feedstock is any biomass containing lignocellulose, and crude wood vinegar comes from the biomass pyrolysis process, including wood vinegar and wood tar; (2) The pretreated biomass raw material obtained in step (1) enters a carbonization reactor for carbonization reaction, and after the reaction is completed, a solid product and a gaseous product are obtained; the carbonization reaction is carried out in two stages, the carbonization reaction temperature of the first stage is 120-300°C, and the carbonization reaction temperature of the second stage is 350-550°C; (3) under contact conditions, mixing the solid product obtained in the carbonization reactor of step (2), the iron-containing oxide, and the potassium-containing compound, and after uniform mixing, entering the gasification reactor for activation, and after activation, performing a steam gasification reaction in the presence of water vapor; (4) The gas phase stream obtained by the gasification reaction in step (3) is further subjected to a water vapor shift reaction and pressure swing adsorption treatment to obtain a hydrogen product.

3. The method for producing hydrogen by a biomass combined process according to claim 1 or 2, wherein: The content of wood vinegar in the crude wood vinegar is 60-70wt%.

4. The method for producing hydrogen by a biomass combined process according to claim 1 or 2, wherein: The mass ratio of the biomass raw material to the crude wood vinegar in step (1) is 1:1 to 1:

6.

5. The method for producing hydrogen by biomass combined process according to claim 2, wherein: The mass ratio of the biomass raw material to the activated carbon in step (1) is 1:0.3 to 1:

2.

6. The method for producing hydrogen by biomass combined process according to claim 2, wherein: The activated carbon in step (1) is one or more of biomass-based activated carbon, asphalt-based activated carbon, and petroleum coke-based activated carbon.

7. The method for producing hydrogen by biomass combined process according to claim 6, wherein: Petroleum coke-based activated carbon is an activated carbon product obtained by activating petroleum coke produced in the coking process. Its specific surface area is 1200~3000m 2 / g, the pore size is 0.5~8nm, and the mesoporosity is 10%~30%.

8. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The drying temperature in step (1) is 40-100°C.

9. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The drying in step (1) is carried out under vacuum conditions.

10. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The iron-containing oxide is selected from one or more of ferroferric oxide, ferrous oxide and ferrous oxide.

11. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The potassium-containing compound is selected from one or more of potassium sulfate, potassium carbonate, potassium chloride, potassium nitrate, potassium tartrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium iodide, potassium bromide, potassium hydroxide, and potassium fluoride.

12. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The potassium-containing compound is selected from one or more of potassium sulfate, potassium carbonate, potassium chloride, potassium nitrate, potassium tartrate, potassium iodide, potassium bromide and potassium hydroxide.

13. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The mass ratio of biomass to iron oxide is 60:1 to 10:

1.

14. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The mass ratio of biomass to potassium-containing compounds is 50:1 to 10:

1.

15. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The activation in the gasification reactor in step (3) is carried out under a reducing atmosphere, the activation temperature is 450-750° C., and the water vapor flow rate is 0.05-0.8 mL / min.

16. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The activation in the gasification reactor in step (3) is carried out under a reducing atmosphere, the activation temperature is 500-700° C., and the water vapor flow rate is 0.05-0.8 mL / min.

17. The method for producing hydrogen using a biomass combined process according to claim 16, wherein: The reducing atmosphere is a gas containing hydrogen, selected from hydrogen, a mixture of hydrogen and a carrier gas, wherein the carrier gas is one or more of helium and nitrogen, and the volume fraction of hydrogen in the mixture is 5% to 50%.

18. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The gasification reaction conditions in step (3) are: reaction temperature 700-950°C, water vapor flow rate 0.05-0.8 mL / min.

19. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The gasification reaction conditions in step (3) are: reaction temperature 750-900°C, water vapor flow rate 0.05-0.8 mL / min.

20. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The water vapor shift reaction conditions in step (4) are as follows: reaction temperature 250-300°C, volume flow ratio of water vapor to gas phase flow 0.5-0.9, gasification gas volume space velocity 1500-2500h -1 .

21. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: The pressure swing adsorption operating conditions in step (4) are: pressure of 1.5-4 MPa and temperature of 20-30°C.

22. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: In step (2), the gaseous product from the carbonization reactor enters the burner for full combustion, and the heat generated by the combustion is supplied to the steam generator, the carbonization reactor, and the gasification reactor.

23. The method for producing hydrogen by biomass combined process according to claim 1 or 2, wherein: In step (2), the gaseous product from the carbonization reactor enters the burner for full combustion, and the heat generated by the combustion is supplied to the steam generator, and the excess heat is used to assist the carbonization reactor and the gasification reactor.

24. A system for producing hydrogen by a biomass combined process for implementing the method for producing hydrogen by a biomass combined process as claimed in any one of claims 1 to 23, comprising the following: A mixer for receiving and mixing a biomass feedstock and crude wood vinegar, or for receiving and mixing a biomass feedstock, crude wood vinegar, and activated carbon; A dryer is used to receive and dry the mixed material from the mixer to obtain the pretreated biomass raw material after drying; The carbonization reactor is used to receive the pretreated biomass raw materials obtained from the dryer. The pretreated biomass raw materials enter the carbonization reactor for carbonization reaction to obtain solid products and gaseous products after the reaction; A gasification reactor is used to receive the solid product, iron-containing oxides, and potassium-containing compounds obtained from the carbonization reactor, mix the solid product, iron-containing oxides, and potassium-containing compounds obtained from the carbonization reactor, activate them, and then contact them with water vapor to react, thereby obtaining a gaseous material stream; A water gas shift reactor, which is used to receive the gaseous material stream obtained after the reaction in the gasification reactor; The pressure swing adsorption reactor is used to receive the gas phase stream obtained after treatment in the water gas shift reactor and obtain hydrogen after treatment.

25. The system for producing hydrogen by biomass combined process according to claim 24, wherein: The dryer is any one or more of a blast drying oven and a vacuum drying oven.

26. The system for producing hydrogen by biomass combined process according to claim 24, wherein: The carbonization reactor adopts any one of a biomass microwave vertical fixed bed reactor, a biomass spiral propulsion carbonization reactor, and a biomass rotary furnace carbonization reactor.

27. The system for producing hydrogen by biomass combined process according to claim 24, wherein: The gasification reactor adopts any one of a microwave vertical fixed bed gasification reactor, a microwave fluidized bed gasification reactor and an electric heating vertical fixed bed reactor.

28. The system for producing hydrogen by biomass combined process according to claim 24, wherein: A water vapor generator is included for generating water vapor.

29. The system for producing hydrogen by a biomass combined process according to claim 24, wherein: The invention comprises a burner. The gas product from the carbonization reactor enters the burner for full combustion. The heat generated by the combustion is supplied to the steam generator, the carbonization reactor and the gasification reactor.

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