Fluidized bed adsorption enhanced hydrogen production from biomass reforming

Abstract

The application provides a fluidized bed adsorption enhanced biomass reforming hydrogen production method and system, and belongs to the field of biomass hydrogen production. The method sends biomass into a pyrolysis gasifier, and after oxygen and steam are introduced, the biomass is pyrolyzed and gasified to generate biomass gas and biomass char; the biomass gas is sent to a reforming hydrogen production furnace; a catalyst is introduced into the reforming hydrogen production furnace; an adsorbent is introduced into a regenerator and then enters the reforming hydrogen production furnace through a return valve, and is mixed with the catalyst to form fluidized binary particles under the action of primary air and secondary air; the biomass gas is mixed with the fluidized binary particles to form a gas-solid mixture, and the biomass gas is converted into H2, CO and CO2 under the action of the catalyst; the adsorbent absorbs CO2 to convert it into calcium carbonate; after the gas-solid mixture is separated, the hydrogen-rich synthesis gas is output through an outlet, the binary particles enter the regenerator, and after catalyst regeneration and adsorbent desorption, the binary particles return to the reforming hydrogen production furnace with the introduced adsorbent. The application improves the hydrogen production efficiency and reduces the cost.

Description

Technical Field

[0001] This invention belongs to the field of biomass hydrogen production, specifically relating to a fluidized bed adsorption-enhanced biomass reforming hydrogen production method and system. Background Technology

[0002] Biomass is the only carbon-neutral renewable energy source that can be stably stored over a long period and has the same dispatchability as traditional fossil fuels. Agricultural waste, as a passive form of biomass, possesses both pollutant and resource attributes; therefore, developing biomass energy according to local conditions is an inevitable choice for sustainable development and a low-carbon economy. Compared to direct biomass combustion, converting biomass into gaseous, liquid, and solid phases, and then further processing it according to the different physicochemical properties of each product to produce high-value-added chemical raw materials and fine chemicals, achieves a cleaner, more efficient, and diversified conversion of biomass, making it more economical and promising for the market.

[0003] In existing technologies, biomass-based hydrogen production is a common biomass application method, including gasification and reforming. Biomass gasification produces hydrogen by reacting biomass with a gasifying agent (usually steam, oxygen, or air) at high temperatures to generate hydrogen-rich gas. Reforming converts the organic matter in biomass into hydrogen through a catalyst. Regardless of the method used, both processes simultaneously convert biomass into biochar, bio-oil, or biogas for downstream energy or chemical feedstock applications.

[0004] Traditional biomass gasification hydrogen production technology faces bottlenecks such as high tar content at low temperatures. Furthermore, the gasification products require a series of complex separation, purification, and reforming processes to obtain a satisfactory product. For example, Chinese invention patent CN114479950B proposes a method and system for biomass pyrolysis gasification hydrogen production. This method directly reacts biomass feedstock with steam and obtains H2 after gas-solid separation, but it does not address the impact of tar and sulfur on catalyst poisoning and deactivation.

[0005] Catalytic biomass reforming for hydrogen production typically employs CO2 adsorption. The adsorbent shifts the chemical reaction towards hydrogen production, increasing both hydrogen yield and purity. Furthermore, the separated CO2 can be directly utilized without energy-intensive capture processes, achieving negative carbon emissions. However, adsorption-enhanced biomass reforming for hydrogen production still suffers from problems such as low H2 yield, high cost, catalyst and adsorbent flow stratification and particle abrasion, reaction timescale mismatch, and catalyst susceptibility to carbon buildup and poisoning. For example, Chinese invention patent CN106629600A proposes a crude syngas adsorption-catalytic hydrogen production process and equipment. This process utilizes a reforming catalyst to adsorb CO2 while simultaneously catalyzing hydrocarbons and carbon tar (C2). 10The process involves converting H8 and CO into H2 and CO2, and then using H2 to reduce and regenerate the catalyst. However, this process reduces the H2 yield and is very costly to prepare bifunctional reforming and catalytic catalysts. Summary of the Invention

[0006] In view of the above-mentioned defects or deficiencies in the prior art, the present invention aims to provide a fluidized bed adsorption-enhanced biomass reforming hydrogen production method and system, which uses binary heterogeneous particles as adsorbent and catalyst respectively. By controlling the flow state of the binary particles in the dual fluidized bed reactor, and in conjunction with the control of fluidization state parameters, the fluidization state is avoided from being disrupted by the stratification of the binary particles, while reducing the wear between particles on the catalyst and adsorbent, reducing carbon buildup, and improving hydrogen production efficiency.

[0007] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0008] In a first aspect, embodiments of the present invention provide a fluidized bed adsorption enhanced biomass reforming hydrogen production system, the system comprising: a biomass pyrolysis-gasification device 1, a reforming hydrogen production device 2, a regeneration device 3, and connecting pipelines;

[0009] In the biomass pyrolysis-gasification device 1, the biomass feeding device 101 is connected to the top of the pyrolysis gasifier 100, the gasifier pure oxygen pipeline 102 and the gasifier steam pipeline 103 are connected to the upper middle part of the pyrolysis gasifier 100; the biomass char outlet 104 is located at the bottom of the pyrolysis gasifier 100, and the biomass gas pipeline 105 is located at the bottom of the pyrolysis gasifier 100 and connected to the bottom of the reforming hydrogen production furnace 200.

[0010] In the reforming hydrogen production unit 2, the reforming hydrogen production furnace 200 has a tall and slender double-bed structure with a height-to-diameter ratio >10. The bottom dense phase zone is a bubbling bed, while the middle and upper dilute phase zones are rapid beds. A reforming furnace heating device 202 is installed outside the furnace body in the upper dilute phase zone. A first steam pipeline 203 is installed at the bottom of the furnace body, and a second steam pipeline 204 is installed in the middle. The catalyst feeding device 201 is connected to the lower middle part of the reforming hydrogen production furnace 200. The top of the reforming hydrogen production furnace 200 is connected to the reforming furnace cyclone separator 205, and a hydrogen-rich syngas outlet 208 is also provided. The bottom outlet of the reforming furnace cyclone separator 205 is connected to the reforming furnace return valve 206, and a reforming furnace return valve steam pipeline 207 is installed at the bottom of the reforming furnace return valve 206. The reforming furnace return valve 206 is connected to the regenerator.

[0011] In the regeneration unit 3, the lower middle part of the regeneration furnace 300 is equipped with an adsorbent feeding device 301, the bottom is equipped with a regeneration furnace steam pipeline 302 and a regeneration furnace pure oxygen inlet 303, the top is connected to the regeneration furnace cyclone separator 304, and the furnace body is equipped with a regeneration furnace heating device 308; the top of the regeneration furnace cyclone separator 304 is equipped with a CO2-rich outlet 305; the lower part of the regeneration furnace 300 is equipped with a regeneration furnace return valve 306, the bottom of the regeneration furnace return valve 306 is equipped with a regeneration furnace return valve steam pipeline 307; the outlet of the regeneration furnace return valve 306 is connected to the lower part of the reforming hydrogen production furnace 200.

[0012] In a preferred embodiment of the present invention, the system further includes a steam generator connected to the treatment water pipeline for providing steam to the gasifier steam pipeline 103, the first steam pipeline 203, the second steam pipeline 204, the reformer return valve steam pipeline 207, the regenerator steam pipeline 302, and the regenerator return valve steam pipeline 307.

[0013] In a preferred embodiment of the present invention, the temperature of the biomass gas pipeline is maintained at 400~500℃; the temperature of the reforming hydrogen production furnace is maintained at 600~750℃; and the temperature of the regeneration furnace is maintained at 800~900℃.

[0014] Secondly, embodiments of the present invention also provide a fluidized bed adsorption-enhanced biomass reforming method for hydrogen production, the method being implemented based on the system described above, specifically including:

[0015] In step S1, the formed biomass pellets are fed into the pyrolysis gasifier by the biomass feeding device. Oxygen is introduced into the pure oxygen pipeline of the gasifier, and steam is introduced into the steam pipeline of the gasifier. The formed biomass pellets undergo pyrolysis and gasification in the gasifier to generate biomass gas and biochar. The biomass gas is transported to the reforming hydrogen production furnace through the biomass gas pipeline, and the biochar is collected outside the output system for subsequent use.

[0016] Step S2: Catalyst particles are conveyed from the catalyst feeder to the dense phase zone of the reforming hydrogen production furnace; adsorbent particles are conveyed from the adsorbent feeder to the regeneration furnace, and then enter the dense phase zone of the reforming hydrogen production furnace through the regeneration furnace return valve, where they mix with the catalyst particles to form binary particles; steam is introduced into the reforming hydrogen production furnace through the first steam pipeline and the second steam pipeline, so that the catalyst and adsorbent binary particles undergo gas-solid two-phase flow and are mixed evenly, and the flow state of the fluidized binary particles is controlled; the reforming hydrogen production furnace is heated by the reforming hydrogen production furnace heating device, and the temperature is maintained at 600~750℃;

[0017] In step S3, biomass gas is introduced into the reforming hydrogen production furnace and mixed with fluidized binary particles to form a gas-solid mixture. In the gas-solid mixture, biomass gas is converted into H2, CO, and CO2 under the action of a catalyst. The CO2 generated by the adsorbent is converted into calcium carbonate and further promotes the conversion of biomass gas. The final gas-solid mixture enters the cyclone separator of the reforming furnace.

[0018] In step S4, the gas-solid mixture is separated by the cyclone separator of the reformer. The separated hydrogen enters the hydrogen separation and purification device through the hydrogen-rich syngas outlet. The purified hydrogen then enters the hydrogen use pipeline through the hydrogen outlet. The separated catalyst and adsorbent binary particles enter the regeneration furnace through the reformer return valve.

[0019] In step S5, the binary particles of catalyst and adsorbent enter the dense phase zone in the middle of the regeneration furnace. Steam is introduced into the steam pipe of the regeneration furnace, causing the binary particles to be in a bubbling bed flow state. At the same time, the catalyst is regenerated under the action of steam, releasing heat. The regeneration furnace is also heated by the regeneration furnace heating device to maintain the temperature of the regeneration furnace at 800~900℃. At this time, the adsorbent undergoes CO2 desorption at high temperature. The regenerated catalyst and the desorbed adsorbent then react with steam to form a gas-solid mixture, which enters the cyclone separator of the regeneration furnace.

[0020] In step S6, the gas-solid mixture is separated by the cyclone separator of the regeneration furnace. The CO2-rich gas enters the gas pipeline through the CO2-rich outlet. The binary particles of catalyst and adsorbent fall into the bottom dense phase zone and are then mixed with the adsorbent fed by the adsorbent feeding device. The mixture then enters the reforming hydrogen production furnace through the return valve.

[0021] In a preferred embodiment of the present invention, the biomass gas comprises: CO, CO2, H2O, CH4, small molecule hydrocarbons and tar.

[0022] In a preferred embodiment of the present invention, the catalyst includes nickel-based artificial catalysts, copper-based artificial catalysts, iron-based artificial catalysts, iron ore, ilmenite, pyrolusite, steel slag and / or coal ash; the adsorbent component includes limestone.

[0023] In a preferred embodiment of the present invention, the flow regime control in step S2 includes:

[0024] The catalyst has a smaller particle size than the adsorbent and a larger specific surface area than the adsorbent. Through the particle size distribution of the catalyst and adsorbent, the catalyst and adsorbent in the fluidized binary particles have the same fluidization characteristic window.

[0025] Adjust the catalyst / adsorbent ratio according to the catalytic reaction rate and adsorption rate;

[0026] The reforming hydrogen production furnace is a dual fluidized bed, with a bubbling bed at the bottom and a fast bed at the top, both adopting a high-density circulating bed form; the regeneration furnace is a bubbling bed, with the temperature maintained at 800~900℃, the residence time of adsorbent particles in the regeneration furnace >20s, the operating wind speed >6 m / s, and the steam residence time controlled at 6-10s;

[0027] The reforming hydrogen production furnace is equipped with graded air distribution. Primary air and secondary air are delivered through the first steam pipeline and the second steam pipeline, respectively. The ratio of primary air to secondary air is adjusted to achieve graded air distribution.

[0028] In a preferred embodiment of the present invention, the catalyst particle size is 30-60 μm, and the adsorbent particle size is 80-150 μm; the mass ratio of catalyst to adsorbent is 1:2 to 1:10; the particle concentration in the bed of the dual fluidized bed in the reforming hydrogen production furnace reaches 30 kg / m³. 3 The circulation flow rate reaches 100-300 kg / m³. 2 •s; the proportion of primary air is 30~70%.

[0029] In a preferred embodiment of the present invention, the H2 content in the hydrogen-rich synthesis gas is ≥90 vol.

[0030] In a preferred embodiment of the present invention, the CO2 enrichment concentration in the CO2-rich gas is ≥95 vol.

[0031] The technical solutions provided in the embodiments of the present invention have the following beneficial effects:

[0032] This application provides a fluidized bed adsorption-enhanced biomass reforming hydrogen production method and system. This method produces high-value-added chemical raw materials and fine chemicals such as biomass green char, green hydrogen, and green methanol from carbon-neutral fuel biomass through a coupled water electrolysis process. This achieves clean, efficient, and diversified biomass conversion. By optimizing particle size distribution, fluidized bed structure, and staged air distribution, the fluidization state of the dual fluidized bed is controlled, ensuring uniform mixing of binary dissimilar particles in the dual fluidized bed system. This avoids the disruption of the fluidization state caused by stratification of binary particles and reduces the wear and tear on the catalyst and adsorbent caused by inter-particle abrasion. The promotion of the reforming hydrogen production process by the mixing of binary particles includes the adsorbent adsorbing CO2, which shifts the reaction to the right, improving hydrogen production efficiency, and enhancing the catalytic effect of the catalyst on the reaction. This approach avoids the problems of complex and costly preparation of bifunctional catalysts. Simultaneously, the binary heterogeneous particles also regulate the reaction atmosphere, and the spatiotemporal evolution of the binary particles can effectively improve the reaction process. The biomass gas and biomass char produced by biomass pyrolysis-gasification are desorbed, preventing ash in the biomass char from poisoning and deactivating the catalyst in the reforming hydrogen production process. Steam is used as the fluidizing and loosening air, avoiding the introduction of nitrogen to dilute the hydrogen-rich syngas when using air. The addition of steam can also reduce the impact of carbon buildup on the catalyst. A highly efficient fractional conversion process route for agricultural biomass has been constructed, with hydrogen-rich syngas having an H2 content ≥90% and a CO2 enrichment concentration ≥95%. The system's continuous operating time and reliability are improved by 25% compared to existing technologies.

[0033] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of the fluidized bed adsorption enhanced biomass reforming hydrogen production system described in an embodiment of the present invention;

[0036] Figure 2 This is a flowchart of the fluidized bed adsorption-enhanced biomass reforming hydrogen production method according to an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Biomass pyrolysis-gasification unit; 100. Pyrolysis gasifier; 101. Biomass feeding device; 102. Gasifier pure oxygen pipeline; 103. Gasifier steam pipeline; 104. Biomass char outlet; 105. Biomass gas pipeline; 2. Reforming hydrogen production unit; 200. Reforming hydrogen production furnace; 201. Catalyst feeding device; 202. Reforming hydrogen production furnace heating device; 203. First steam pipeline; 204. Second steam pipeline; 205. Reformer cyclone separator; 206. Reforming 207. Reformer return valve steam pipeline; 208. Hydrogen-rich synthesis gas outlet; 209. Hydrogen separation and purification device; 210. Hydrogen outlet; 3. Regeneration device; 300. Regeneration furnace; 301. Adsorbent feeding device; 302. Regeneration furnace steam pipeline; 303. Regeneration furnace pure oxygen inlet; 304. Regeneration furnace cyclone separator; 305. CO2-rich outlet; 306. Regeneration furnace return valve; 307. Regeneration furnace return valve steam pipeline; 308. Regeneration furnace heating device. Detailed Implementation

[0039] After discovering the aforementioned problems, the inventors of this application conducted a detailed study of existing biomass hydrogen production technologies. The study found that in the process of biomass reforming for hydrogen production via catalysts, bifunctional catalysts are typically used to catalyze the reforming process while simultaneously performing adsorption. However, bifunctional catalysts often have complex preparation processes and high costs. Furthermore, particle wear and consumption are severe problems in fluidized bed reactors; the active sites loaded on the particle surface easily disappear during operation, leading to the material losing its catalytic effect. Moreover, the high-cost bifunctional catalysts require large-scale replenishment to the reactor, increasing both process complexity and cost. In the biomass reforming hydrogen production process, there is also a mismatch between the catalytic reaction and the adsorption reforming reaction. This mismatch is one of the major bottlenecks restricting its efficient and stable operation. When the adsorbent reaction rate is slower than the catalytic reaction rate, the CO2 generated by the catalytic reaction cannot be adsorbed by the adsorbent in time, resulting in product accumulation, a shift in reaction equilibrium, and a reduction in H2 yield. The significant differences between catalysts and adsorbents in terms of thermal stability, mechanical strength, and coefficient of thermal expansion can easily lead to particle breakage, wear, or sintering. In addition, biomass gas contains a large amount of CO, CH4 and some heavy hydrocarbons or tar components. Under high temperature, driven by thermodynamic characteristics, it is easy to undergo cracking reaction to generate H2 and carbon, which cover the catalyst surface, thereby blocking the active sites of metals such as Ni, Fe, and Co, causing catalyst carbon deposition and deactivation. Carbon deposition may also lead to problems such as particle agglomeration, fluid state deterioration and repeated regeneration in the reactor, affecting the stable operation of the fluidized bed system.

[0040] It should be noted that the defects in the above-mentioned prior art solutions are all the result of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present invention in the following text should be the inventors' contributions to the present invention.

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0042] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0043] After the above in-depth analysis, the present invention provides a fluidized bed adsorption enhanced biomass reforming hydrogen production method and system. After the biomass particles are pyrolyzed and gasified in the biomass pyrolysis-gasification device, the generated biomass gas enters the reforming hydrogen production device. Under the condition of uniform mixing of adsorbent and catalyst binary particles, CO2 is adsorbed and CH4, CO, tar and other substances are catalytically converted to produce hydrogen-rich syngas. Then the binary mixed particles enter the regeneration device for CO2 desorption and catalyst regeneration. This application employs flow regime control methods such as particle size distribution, structural optimization, and graded air distribution to avoid disrupting the fluidization state due to stratification of binary particles and to reduce the wear and tear on catalysts and adsorbents caused by interparticle abrasion. Simultaneously, the direct use of binary particles avoids the complex and costly preparation of bifunctional catalysts. Decoupling the generated biomass gas and biomass char prevents ash in the biomass char from poisoning and deactivating the reforming hydrogen production catalyst, while simultaneously obtaining high-value biomass char. The constructed efficient biomass fractional conversion process route can achieve hydrogen-rich syngas with an H2 content ≥90% and a CO2 enrichment concentration ≥95%, realizing clean, efficient, and multi-element conversion of biomass.

[0044] like Figure 1 As shown, the fluidized bed adsorption enhanced biomass reforming hydrogen production system includes: a biomass pyrolysis-gasification unit 1, a reforming hydrogen production unit 2, a regeneration unit 3, and connecting pipelines.

[0045] The biomass pyrolysis-gasification unit 1 includes a pyrolysis gasifier 100, a biomass feeding device 101, a gasifier pure oxygen pipeline 102, a gasifier steam pipeline 103, a biomass char outlet 104, and a biomass gas pipeline 105. The biomass feeding device 101 is connected to the top of the pyrolysis gasifier 100, and the gasifier pure oxygen pipeline 102 and the gasifier steam pipeline 103 are connected to the upper middle part of the pyrolysis gasifier 100. The biomass char outlet 104 is located at the bottom of the pyrolysis gasifier 100, and the biomass gas pipeline 105 is connected from the bottom of the pyrolysis gasifier 100 to the bottom of the reforming hydrogen production furnace 200 of the reforming hydrogen production unit 2.

[0046] The reforming hydrogen production unit 2 includes a reforming hydrogen production furnace 200, a catalyst feeding device 201, a reforming furnace heating device 202, a first steam pipeline 203, a second steam pipeline 204, a reforming furnace cyclone separator 205, a reforming furnace return valve 206, a reforming furnace return valve steam pipeline 207, a hydrogen-rich syngas outlet 208, a hydrogen separation and purification device 209, and a hydrogen outlet 210. The reforming hydrogen production furnace 200 has a tall and slender double-bed structure with a height-to-diameter ratio >10. The bottom dense phase zone is a bubbling bed, while the middle and upper dilute phase zones are rapid beds. The reforming furnace heating device 202 is installed outside the furnace body in the upper dilute phase zone. A first steam pipeline is installed at the bottom of the furnace body. The first steam pipe 203 has a second steam pipe 204 in the middle. The first steam pipe 203 enters the bottom dense phase zone as primary air, and the second steam pipe 204 enters the middle dilute phase zone as secondary air. The catalyst feeder 201 is connected to the middle and lower part of the reforming hydrogen production furnace 200. The top outlet of the reforming hydrogen production furnace 200 is connected to the reforming furnace cyclone separator 205. The bottom outlet of the reforming furnace cyclone separator 205 is connected to the reforming furnace return valve 206 and the reforming furnace return valve steam pipe 207. The top outlet of the reforming furnace cyclone separator 205 is connected to the hydrogen-rich synthesis gas outlet 208, and then connected to the hydrogen separation and purification device 209 and the hydrogen outlet 210.

[0047] The regeneration unit 3 includes a regeneration furnace 300, an adsorbent feeding device 301, a regeneration furnace steam pipeline 302, a regeneration furnace pure oxygen inlet 303, a regeneration furnace cyclone separator 304, a CO2-rich outlet 305, a regeneration furnace return valve 306, a regeneration furnace return valve steam pipeline 307, and a regeneration furnace heating device 308. The reforming hydrogen production furnace return valve 206 is connected to the regeneration furnace 300. The adsorbent feeding device 301 enters from the lower middle part of the regeneration furnace 300. The regeneration furnace steam pipeline 302 and the regeneration furnace... The pure oxygen inlet 303 is connected to the bottom of the regeneration furnace 300; the top of the regeneration furnace 300 is connected to the regeneration furnace cyclone separator 304, and the top of the regeneration furnace cyclone separator 304 is provided with a CO2-rich outlet 305; the lower part of the regeneration furnace 300 is connected to the regeneration furnace return valve 306, and the bottom of the regeneration furnace return valve 306 is connected to the regeneration furnace return valve steam pipeline 307; the outlet of the regeneration furnace return valve 306 is connected to the lower part of the reforming hydrogen production furnace 200; a regeneration furnace heating device 308 is provided on the outside of the regeneration furnace 300.

[0048] The system may also include a steam generator connected to the treatment water pipeline for providing steam to the gasifier steam pipeline 103, the first steam pipeline 203 and the second steam pipeline 204 of the reforming hydrogen production furnace, the reforming furnace return valve steam pipeline 207, the regenerator steam pipeline 302, and the regenerator return valve steam pipeline 307.

[0049] Based on the fluidized bed adsorption-enhanced biomass reforming hydrogen production system described above, this invention also provides a fluidized bed adsorption-enhanced biomass reforming hydrogen production method; such as Figure 2 As shown, the method includes:

[0050] In step S1, the formed biomass pellets are fed into the pyrolysis gasifier of the biomass pyrolysis-gasification device by the biomass feeding device. Oxygen is introduced into the pure oxygen pipeline of the gasifier, and steam is introduced into the steam pipeline of the gasifier. The formed biomass pellets undergo pyrolysis and gasification to generate biomass gas and biochar. The biomass gas is transported to the reforming hydrogen production furnace by the biomass gas pipeline, and the biochar is collected outside the output system for subsequent use.

[0051] In this step, the temperature of the biomass gas pipeline is maintained at 400~500℃; the remaining solid phase component, biochar, after gasification is collected through the biochar outlet. The components of the biomass gas include: CO, CO2, H2O, CH4, small molecule hydrocarbons, and tar.

[0052] In this step, biomass is pyrolyzed and gasified in a pyrolysis gasifier to obtain biomass gas and biochar. The biomass gas and biochar are then decoupled in the gasifier and transported to different pipelines to prevent the biochar from entering the reforming hydrogen production process. This avoids the ash content from poisoning and deactivating the reforming hydrogen production catalyst, while simultaneously obtaining high-value biochar.

[0053] In step S2, catalyst particles are conveyed from the catalyst feeding device to the dense phase zone of the reforming hydrogen production furnace; adsorbent particles are conveyed from the adsorbent feeding device to the regeneration furnace, and then enter the dense phase zone of the reforming hydrogen production furnace through the regeneration furnace return valve, where they mix with the catalyst particles to form binary particles; steam is introduced into the reforming hydrogen production furnace through the first steam pipeline and the second steam pipeline, so that the catalyst and adsorbent binary particles undergo gas-solid two-phase flow and are mixed evenly, and the flow state of the fluidized binary particles is controlled; the reforming hydrogen production furnace is heated by the reforming hydrogen production furnace heating device, and the temperature is maintained at 600~750℃.

[0054] In this step, the catalyst and adsorbent binary particles serve two purposes: firstly, the catalyst catalyzes the reaction, and secondly, the adsorbent adsorbs the generated carbon dioxide gas, promoting the reaction to proceed to the right and improving hydrogen production efficiency. At the same time, the adsorbent absorbs the released heat and provides it to the reaction process. In addition, the catalyst and adsorbent are in a mixed state of binary particles, rather than a bifunctional single-particle state, which avoids the problem of high cost of replenishing the catalyst and adsorbent after preparation and consumption.

[0055] Preferably, the catalyst particles are composed of artificial catalysts such as nickel-based, copper-based, and iron-based catalysts, or natural catalysts such as iron ore, ilmenite, pyrolusite, steel slag, and coal ash. The adsorbent particles include limestone.

[0056] In this step, the flow regime control includes particle size distribution, binary ratio, bed structure, and staged air distribution. Specifically, it includes:

[0057] The catalyst has a smaller particle size than the adsorbent but a larger specific surface area. Through particle size distribution, the catalyst and adsorbent in the fluidized binary particles have the same fluidization characteristic window, achieving uniform mixing and avoiding stratification or uneven fluidization that could disrupt the fluidization process. This also reduces interparticle wear on the catalyst and adsorbent. Preferably, the catalyst particle size is 30-60 μm, and the adsorbent particle size is 80-150 μm. By controlling the particle size matching of the binary particles, the rates of the catalytic and reforming reactions, as well as the heat and mass transfer processes, are coordinated, improving the overall hydrogen production efficiency.

[0058] The catalyst / adsorbent ratio is adjusted according to the catalytic reaction rate and adsorption rate. Preferably, the catalyst:adsorbent ratio is 1:2 to 1:10 (mass ratio).

[0059] The reforming hydrogen production furnace is a dual fluidized bed system, with a bubbling bed at the bottom and a rapid-flow bed at the top, both employing a high-density circulating bed configuration; preferably, the particle concentration in the bed reaches 30 kg / m³. 3 The circulation flow rate reaches 100-300 kg / m³. 2•s, temperature maintained at 600~750℃; this allows the binary particles of catalyst and adsorbent to reflux at high speed, thereby maintaining the high-density and stable operation of the bed; the regeneration furnace is a bubbling bed, the temperature is maintained at 800~900℃, the residence time of adsorbent particles in the regeneration furnace is >20s, the operating wind speed is >6 m / s, and the steam residence time is controlled at 6-10s.

[0060] The reforming hydrogen production furnace employs a staged air distribution system, supplying primary and secondary air through a first and second steam pipeline, respectively. By adjusting the ratio of primary and secondary air, staged air distribution is achieved, thereby controlling the atmosphere distribution and fluidization state within the furnace, reducing localized catalyst overheating, and simultaneously promoting vigorous particle fluidization for dust removal to mitigate carbon buildup. Preferably, the primary air ratio is 30-70%, and the secondary air ratio is 70-30%.

[0061] In step S3, biomass gas is introduced into the reforming hydrogen production furnace and mixed with fluidized binary particles to form a gas-solid mixture. In the gas-solid mixture, biomass gas is converted into H2, CO, and CO2 under the action of a catalyst. The CO2 generated by the adsorbent is converted into calcium carbonate and further promotes the conversion of biomass gas. Finally, the gas-solid mixture enters the cyclone separator of the reforming furnace.

[0062] In this step, the chemical reactions of biomass gas under the action of a catalyst include:

[0063] (1)

[0064] (2)

[0065] (3)

[0066] (4)

[0067] (5)

[0068] Equation (3) represents the decomposition reaction of tar components in biomass gas under the action of a catalyst. The catalyst converts the tar in biomass gas into H2, thereby reducing the carbon deposition problem.

[0069] In step S4, the gas-solid mixture is separated by a cyclone separator in the reformer. The separated hydrogen enters the hydrogen separation and purification device through the hydrogen-rich syngas outlet, and the purified hydrogen enters the hydrogen use pipeline through the hydrogen outlet. The separated catalyst and adsorbent binary particles enter the regeneration furnace through the reformer return valve.

[0070] In this step, the H2 content in the hydrogen-rich synthesis gas is ≥90 vol.%.

[0071] During the biomass gas reaction process in the reforming hydrogen production furnace, the catalyst and adsorbent gradually deactivate. In this embodiment, steam is introduced through the steam pipeline of the reforming furnace return valve. By adjusting the loosening airflow in the return valve, the purging capacity for particles at the outlet of the cyclone separator in the reforming hydrogen production furnace is enhanced, accelerating the carrying speed of deactivated particles and allowing fine, deactivated particles to be blown away from the system by the airflow. Addressing the problem of catalyst or adsorbent particles during the reaction process, this embodiment proposes selective discharge by adjusting the separation efficiency of the cyclone separator in the reforming hydrogen production furnace and the return air operation of the return valve in this step of the reforming hydrogen production unit. This blows out fine particles while keeping larger particles within the system.

[0072] In step S5, the binary particles of catalyst and adsorbent enter the dense phase zone in the middle of the regeneration furnace. Steam is introduced into the steam pipeline of the regeneration furnace, so that the binary particles are in a bubbling bed flow state. At the same time, the catalyst is regenerated under the action of steam and heat is released. The regeneration furnace is heated by the regeneration furnace heating device to maintain the temperature of the regeneration furnace at 800~900℃. At this time, the adsorbent undergoes CO2 desorption at high temperature. The regenerated catalyst and the desorbed adsorbent then react with steam to form a gas-solid mixture, which enters the cyclone separator of the regeneration furnace.

[0073] In step S6, the gas-solid mixture is separated by the cyclone separator of the regeneration furnace. The CO2-rich gas enters the gas pipeline through the CO2-rich outlet. The binary particles of catalyst and adsorbent fall into the bottom dense phase zone and are then mixed with the adsorbent fed by the adsorbent feeding device. The mixture then enters the reforming hydrogen production furnace through the return valve.

[0074] In this step, the CO2 enrichment concentration in the CO2-rich gas is ≥95 vol.%. The CO2-rich gas from the CO2-rich outlet and the hydrogen-rich syngas from the hydrogen-rich syngas outlet can be fed into the methanol synthesis tower to synthesize methanol, a high-value industrial raw material, or used in other industries that require hydrogen or CO2.

[0075] The cyclone separator in this step, like the cyclone separator in the reformer, is also equipped with a steam pipeline for the return valve of the regeneration furnace. By adjusting the loose air volume in the return valve, the purging ability of the particles at the outlet of the cyclone separator of the regeneration furnace is enhanced, thus completing the material circulation within the system.

[0076] Therefore, the fluidized bed adsorption-enhanced biomass gas reforming hydrogen production method and system provided in this invention enables the catalytic reaction and adsorption reforming behavior to proceed synergistically under different flow states, thereby improving hydrogen production efficiency; the binary heterogeneous particles also play a role in regulating the reaction atmosphere, and the spatiotemporal evolution of the flow state of the binary particles can effectively promote the reaction process; it achieves efficient recycling and utilization of adsorbent and catalyst; it promotes particle agitation and distribution through flow state regulation, reducing catalyst carbon deposition problems; and it also reduces raw material costs.

[0077] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A fluidized bed adsorption-enhanced biomass reforming hydrogen production system, characterized in that, The system includes: a biomass pyrolysis-gasification unit, a reforming hydrogen production unit, a regeneration unit, and connecting pipelines; In the biomass pyrolysis-gasification unit, the biomass feeding device is connected to the top of the pyrolysis gasifier, and the pure oxygen pipeline and steam pipeline of the gasifier are connected to the upper middle part of the pyrolysis gasifier; the biomass char outlet is located at the bottom of the pyrolysis gasifier, and the biomass gas pipeline is set at the bottom of the pyrolysis gasifier and connected to the bottom of the reforming hydrogen production furnace. In the reforming hydrogen production unit, the reforming furnace is a tall and slender double-bed structure with a height-to-diameter ratio >10. The bottom dense phase zone is a bubbling bed, while the middle and upper dilute phase zones are rapid beds. A reforming furnace heating device is installed outside the furnace body in the upper dilute phase zone. A first steam pipeline is installed at the bottom of the furnace body, and a second steam pipeline is installed in the middle. The catalyst feeding device is connected to the lower middle part of the reforming hydrogen production furnace. The top of the reforming hydrogen production furnace is connected to the reforming furnace cyclone separator and is equipped with a hydrogen-rich syngas outlet. The bottom outlet of the reforming furnace cyclone separator is connected to the reforming furnace return valve, and a reforming furnace return valve steam pipeline is installed at the bottom of the reforming furnace return valve. The reforming furnace return valve is connected to the regenerator. The first steam pipeline is used to transport primary air into the bottom dense phase zone, and the second steam pipeline is used to transport secondary air into the middle dilute phase zone, thereby controlling the atmosphere distribution and fluidization state in the furnace and reducing local overheating of the catalyst. At the same time, the particles are vigorously fluidized to remove ash and reduce carbon buildup. In the regeneration unit, the lower middle part of the regeneration furnace is equipped with an adsorbent feeding device, the bottom is equipped with a regeneration furnace steam pipeline and a regeneration furnace pure oxygen inlet, the top is connected to the regeneration furnace cyclone separator, and the furnace body is equipped with a regeneration furnace heating device; the top of the regeneration furnace cyclone separator is equipped with a CO2-rich outlet; the lower part of the regeneration furnace is equipped with a regeneration furnace return valve, and the bottom of the regeneration furnace return valve is equipped with a regeneration furnace return valve steam pipeline; the outlet of the regeneration furnace return valve is connected to the lower part of the reforming hydrogen production furnace. The catalyst used in the system has a smaller particle size than the adsorbent and a larger specific surface area than the adsorbent. Through the particle size distribution of the catalyst and adsorbent, the catalyst and adsorbent in the fluidized binary particles have the same fluidization characteristic window. The system also includes a steam generator connected to the treatment water pipeline for supplying steam to the gasifier steam pipeline, the first steam pipeline, the second steam pipeline, the reformer return valve steam pipeline, the regenerator steam pipeline, and the regenerator return valve steam pipeline.

2. The system according to claim 1, characterized in that, The temperature of the biomass gas pipeline is maintained at 400~500℃; the temperature of the reforming hydrogen production furnace is maintained at 600~750℃; and the temperature of the regeneration furnace is maintained at 800~900℃.

3. A fluidized bed adsorption-enhanced biomass reforming method for hydrogen production, characterized in that, The method is implemented based on the system described in claim 1 or 2, and specifically includes: In step S1, the formed biomass pellets are fed into the pyrolysis gasifier by the biomass feeding device. Oxygen is introduced into the pure oxygen pipeline of the gasifier, and steam is introduced into the steam pipeline of the gasifier. The formed biomass pellets undergo pyrolysis and gasification in the gasifier to generate biomass gas and biochar. The biomass gas is transported to the reforming hydrogen production furnace through the biomass gas pipeline, and the biochar is collected outside the output system for subsequent use. Step S2: Catalyst particles are fed into the dense phase zone of the reforming hydrogen production furnace by the catalyst feeding device; adsorbent particles are fed into the regeneration furnace by the adsorbent feeding device, and then enter the dense phase zone of the reforming hydrogen production furnace through the regeneration furnace return valve, where they mix with the catalyst particles to form binary particles; steam is introduced into the reforming hydrogen production furnace through the first steam pipeline and the second steam pipeline, with the first steam pipeline delivering primary air into the bottom dense phase zone and the second steam pipeline delivering secondary air into the middle dilute phase zone, causing the catalyst and adsorbent binary particles to undergo gas-solid two-phase flow and mix evenly, thereby controlling the flow state of the fluidized binary particles, controlling the atmosphere distribution and fluidization state in the furnace, reducing local overheating of the catalyst, and simultaneously promoting particle fluidization and ash removal to reduce carbon buildup; the reforming hydrogen production furnace is heated by the reforming hydrogen production furnace heating device, and the temperature is maintained at 600~750℃; The flow regime control includes: The catalyst has a smaller particle size than the adsorbent and a larger specific surface area than the adsorbent. Through the particle size distribution of the catalyst and adsorbent, the catalyst and adsorbent in the fluidized binary particles have the same fluidization characteristic window. Adjust the catalyst / adsorbent ratio according to the catalytic reaction rate and adsorption rate; The reforming hydrogen production furnace is a dual fluidized bed, with a bubbling bed at the bottom and a fast bed at the top, both adopting a high-density circulating bed form; the regeneration furnace is a bubbling bed, with the temperature maintained at 800~900℃, the residence time of adsorbent particles in the regeneration furnace >20s, the operating wind speed >6 m / s, and the steam residence time controlled at 6-10s; The reforming hydrogen production furnace is equipped with staged air distribution. Primary air and secondary air are delivered through the first steam pipeline and the second steam pipeline, respectively. The ratio of primary air and secondary air is adjusted to achieve staged air distribution. In step S3, biomass gas is introduced into the reforming hydrogen production furnace and mixed with fluidized binary particles to form a gas-solid mixture. In the gas-solid mixture, biomass gas is converted into H2, CO, and CO2 under the action of a catalyst. The CO2 generated by the adsorbent is converted into calcium carbonate and further promotes the conversion of biomass gas. The final gas-solid mixture enters the cyclone separator of the reforming furnace. In step S4, the gas-solid mixture is separated by a cyclone separator in the reformer. The separated hydrogen enters a hydrogen separation and purification unit through the hydrogen-rich syngas outlet, and the purified hydrogen then enters the hydrogen consumption pipeline through the hydrogen outlet. The separated catalyst and adsorbent binary particles enter the regeneration furnace through the reformer return valve. The H2 content in the hydrogen-rich syngas is ≥90 vol.%. In step S5, the binary particles of catalyst and adsorbent enter the dense phase zone in the middle of the regeneration furnace. Steam is introduced into the steam pipe of the regeneration furnace, causing the binary particles to be in a bubbling bed flow state. At the same time, the catalyst is regenerated under the action of steam, releasing heat. The regeneration furnace is also heated by the regeneration furnace heating device to maintain the temperature of the regeneration furnace at 800~900℃. At this time, the adsorbent undergoes CO2 desorption at high temperature. The regenerated catalyst and the desorbed adsorbent then react with steam to form a gas-solid mixture, which enters the cyclone separator of the regeneration furnace. In step S6, the gas-solid mixture is separated by the cyclone separator of the regeneration furnace. The CO2-rich gas enters the gas pipeline through the CO2-rich outlet. The catalyst and adsorbent binary particles fall into the bottom dense phase zone and are then mixed with the adsorbent fed by the adsorbent feeding device. The mixture then enters the reforming hydrogen production furnace through the return valve. The CO2 enrichment concentration in the CO2-rich gas is ≥95 vol.

4. The method according to claim 3, characterized in that, The components of the biomass gas include: CO, CO2, H2O, CH4, small molecule hydrocarbons, and tar.

5. The method according to claim 3, characterized in that, The catalyst includes nickel-based synthetic catalysts, copper-based synthetic catalysts, iron-based synthetic catalysts, iron ore, ilmenite, pyrolusite, steel slag and / or coal ash; the adsorbent component includes limestone.

6. The method according to claim 3, characterized in that, The catalyst particle size is 30-60 μm, and the adsorbent particle size is 80-150 μm; the mass ratio of catalyst to adsorbent is 1:2 to 1:10; the particle concentration in the bed of the dual fluidized bed in the reforming hydrogen production furnace reaches 30 kg / m³. 3 The circulation flow rate reaches 100-300 kg / m³. 2 •s; the proportion of primary air is 30~70%.

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