System and method for producing hydrogen by biomass three-stage adsorption enhanced reforming in double heat supply modes

Abstract

The invention provides a double-heat-supply-mode biomass three-stage adsorption enhanced reforming hydrogen production system and a double-heat-supply-mode biomass three-stage adsorption enhanced reforming hydrogen production method. The system is formed by sequentially connecting a biomass feeding system, a pyrolysis system, a continuous adsorption enhanced fluidized bed, a continuous catalytic reforming fluidized bed and a synthesis gas separation and purification and double-source coupling heat supply system, CO2 is removed online through the adsorption enhanced fluidized bed to break reaction equilibrium, and the catalytic reforming fluidized bed is coupled to realize directional cracking and deep reforming of tar. Therefore, the hydrogen yield and purity are synergistically improved. According to the method, a renewable energy source and slag combustion double-source complementary heat supply mode is adopted, all-time stable energy supply is achieved, and energy consumption and cost are greatly reduced. The system is also integrated with an adsorbent and catalyst in-situ regeneration circulation loop, so that continuous and long-acting operation of the system is guaranteed. According to the invention, the bottlenecks of low yield, high energy consumption, discontinuous operation and the like in the traditional biomass hydrogen production technology are effectively solved, and efficient, economical and environment-friendly conversion from biomass to high-purity hydrogen is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomass resource utilization, and particularly relates to a system and method for hydrogen production by biomass three-stage adsorption enhanced reforming in a double-heat-supply mode. BACKGROUND

[0002] Hydrogen production by biomass thermochemical conversion is an important technical path for converting renewable carbon resources into clean energy. At present, this technology mainly focuses on pyrolysis, gasification, and subsequent reforming and purification.

[0003] However, the existing biomass hydrogen production technology still has several technical bottlenecks to be solved. First, the system integration degree is usually low, and the feed, pyrolysis, reforming, and purification units are usually independent devices connected by long pipelines, resulting in high heat loss rate, large occupied area, and difficulty in efficient coordination of materials and energy. Second, the reaction path design is rough, and the volatiles produced by pyrolysis are usually directly subjected to catalytic reforming, in which high concentration of CO2 will restrict the thermodynamic equilibrium of the reforming reaction, resulting in low hydrogen production rate; at the same time, the tar components in the volatiles are easy to cause carbon deposition and poisoning of the catalyst, which not only affects the purity of hydrogen, but also seriously restricts the continuity of the device operation. In addition, the system heat supply is mainly dependent on external power grid or fossil fuels, which has high energy consumption cost, and the chemical energy contained in the solid residues (slag) generated in the pyrolysis process is not fully utilized.

[0004] Therefore, it is of great significance to provide a system and method for hydrogen production by biomass that can realize efficient integration, optimized reaction path, energy self-sufficiency, and long-term stable operation, to promote the industrial application of this technology. SUMMARY

[0005] One of the purposes of the present application is to provide a system for hydrogen production by biomass three-stage adsorption enhanced reforming in a double-heat-supply mode, which solves the technical problems of system fragmentation, high energy consumption, and inability to continuously and stably operate in the existing biomass pyrolysis technology through integrated design and double-source heat supply.

[0006] The second purpose of the present application is to provide a hydrogen production method based on the above-mentioned system, which realizes efficient, economic, and environmentally friendly conversion of biomass to high-purity hydrogen by constructing a three-stage reaction path including adsorption enhancement and catalytic reforming.

[0007] The technical solution adopted by one of the purposes of the present application is to provide a system for hydrogen production by biomass three-stage adsorption enhanced reforming in a double-heat-supply mode, which includes a biomass feed system, a pyrolysis reaction system, a continuous adsorption enhanced fluidized bed system, a continuous catalytic reforming fluidized bed system, a syngas separation and purification system, and a double-source coupled heat supply system connected in sequence. The continuous adsorption intensified fluidized bed system is used for passing non-condensable gas from the pyrolysis reaction system and selectively adsorbing and removing CO2 in a fluidized state of the adsorbent; and the system is also provided with an adsorbent regeneration and circulation loop for regenerating and recycling the adsorbent. The continuous catalytic reforming fluidized bed system is used for passing gas from the continuous adsorption intensified fluidized bed system and performing directional bond breaking and small molecule reforming reactions of tar through a fluidized state of the catalyst; and the system is also provided with a catalyst regeneration and circulation loop for regenerating and recycling the catalyst. The dual-source coupled heat supply system comprises a renewable energy driven heat supply device and a slag combustion heat supply device; the renewable energy driven heat supply device supplies heat for each reaction system by using renewable energy; and the slag combustion heat supply device is connected with a slag discharge outlet of the pyrolysis reaction system and is used for combusting pyrolysis slag and supplying heat for each reaction system.

[0008] The overall idea and inventive principle of the present application are as follows: The present application provides a systematic solution to the technical bottleneck of low system integration, insufficient reaction efficiency, high energy consumption and difficulty in continuous and stable operation in the existing biomass hydrogen production technology, and the core idea is to build an efficient collaborative system integrating three-level reactions, dual-source heat supply and material circulation.

[0009] Firstly, in the reaction path, the present application designs a new reaction path by sequentially combining the two key steps of online adsorption intensification and catalytic reforming. The continuous adsorption intensified fluidized bed system selectively removes CO2 in a fluidized state, not only purifying the reaction gas, but more importantly breaking the thermodynamic equilibrium limitation of the subsequent reforming reaction and actively driving the reaction to the high hydrogen production direction; the continuous catalytic reforming fluidized bed system that follows is specifically directed to the directional bond breaking of tar and the deep reforming of small molecules, thereby significantly improving the hydrogen production rate and purity as a whole.

[0010] Secondly, in order to realize continuous production, the present application sets up an in-situ regeneration and circulation loop for the adsorbent and the catalyst, solves the problem of frequent replacement due to easy deactivation, and guarantees the stability of long-term operation of the system. At the same time, the present application also configures a dual-source coupled heat supply system, which combines the external intermittent renewable energy (solar energy, wind energy) with the combustion heat energy of the solid waste (pyrolysis slag) generated inside the system, forms a complementary stable energy supply mode, and greatly reduces the dependence on external fossil energy and the energy consumption of system operation.

[0011] Finally, all subsystems (feed, pyrolysis, adsorption, reforming, separation, heat supply) in the system provided by the present application are designed as a closed material loop that is closely connected in sequence, greatly reducing the transmission loss of energy and material, and realizing the full-component and efficient conversion of biomass resources from raw materials to high-purity hydrogen, thereby providing a feasible scheme with economic and environmental protection for the industrial application of biomass hydrogen production.

[0012] Further, the reactor of the continuous adsorption enhanced fluidized bed system and the continuous catalytic reforming fluidized bed system is provided with multiple layers of inclined and staggered guide plates, which are used to optimize the gas-solid contact and prolong the gas residence time.

[0013] The present application solves the problems of uneven gas-solid contact and short-circuit flow in traditional fluidized beds by providing multiple layers of guide plates in the reactor of the continuous adsorption enhanced fluidized bed system and the continuous catalytic reforming fluidized bed system to optimize the flow field distribution in the fluidized bed. Specifically, the staggered guide plates arranged at a specific angle can effectively block and redistribute the upward gas flow, forcing the flow path of the gas and the adsorbent particles or catalyst particles to be more tortuous and complex. This design significantly increases the effective contact area of the gas-solid two-phase, and prolongs the gas residence time in the bed from less than 2s to 3-5s. The direct technical effect is that in the continuous adsorption enhanced fluidized bed, the CO2 adsorbent can react more fully and completely with the pyrolysis gas, thereby increasing the CO2 adsorption efficiency of the system from less than 70% in the prior art to more than 85%, laying a solid foundation for the efficient reaction in the subsequent catalytic reforming stage; in the continuous catalytic reforming fluidized bed, the catalyst and decarburization gas also have prolonged contact time under the action of the guide plates, making the bond-breaking reforming reaction more complete and thorough.

[0014] Further, the adsorbent regeneration and circulation loop and / or the catalyst regeneration and circulation loop are provided with a regenerator; the regenerator is connected to the corresponding fluidized bed through a separation device, and a heating assembly and an inert gas purging unit are provided inside the regenerator to realize the regeneration function. Specifically, the inert gas purging unit is used to introduce inert gas (such as nitrogen, argon) during the regeneration process, and to timely remove the CO2 and other gas products generated by the decomposition of the regenerator, to promote the forward movement of the regeneration reaction equilibrium, and to further improve the regeneration efficiency. The regenerator is connected to the solid outlet of the cyclone separator through a sealed pipeline, and the regenerated adsorbent or catalyst is accurately returned to the corresponding fluidized bed reactor through a dosing feeder, thereby realizing closed and continuous in-situ regeneration and circulation.

[0015] Preferably, the temperature of the adsorbent regenerator is controlled at 900-1000℃, which is the optimal balance point to ensure the complete decomposition of the carbonates generated in the calcium-based or magnesium-based adsorbent, while avoiding its sintering inactivation.

[0016] Preferably, the temperature of the catalyst regenerator is controlled at 700-800℃, which can effectively burn off the carbon deposition and other toxic substances on the surface of the catalyst, restore its active sites, and prevent the aggregation and sintering of active metals (such as Ni) due to overheating.

[0017] The present application controls the regeneration temperature in its specific optimization range, which aims to maximize the inhibition of structural damage and inactivation of the adsorbent and catalyst at high temperatures while ensuring the complete removal of pollutants and the restoration of material activity. This precise temperature control strategy, combined with the synergistic effect of inert gas purging, significantly prolongs the service life of the adsorbent and catalyst. In some better embodiments, the number of cycles can be increased to more than 50 times, and the activity decay after each regeneration can be controlled within 15%, thereby ensuring that the system can operate stably and continuously for a long time.

[0018] Further, the synthesis gas separation and purification system comprises a condensation tar removal unit, a pressure swing adsorption hydrogen extraction unit, and a palladium membrane precision purification unit connected in sequence. The integrated purification route adopted by the present application aims to realize efficient and stable conversion from complex raw synthesis gas to ultra-high purity hydrogen through hierarchical purification and functional complementation.

[0019] Preferably, the condensation tar removal unit is a jacketed condensation tank, which is supplied with cooling water at -5-10℃ in the jacket, and is supplemented with activated carbon adsorbent. This unit aims to capture and remove residual tar and water vapor that has not been converted or re-condensed after catalytic reforming, and through the synergistic effect of condensation and adsorption, it creates clean feed conditions for the subsequent tar-sensitive pressure swing adsorption hydrogen extraction unit and palladium membrane precision purification unit.

[0020] Preferably, after the condensation tar removal unit, a water washing pool and a drying chamber are connected in sequence. The water washing pool is filled with ceramic Raschig rings and other fillers, and through countercurrent spraying, it further removes dust and trace tar; the drying chamber is equipped with molecular sieve desiccant, which is used for deep dehydration to reduce the dew point of the gas to below -40℃, in order to protect the subsequent adsorbent and palladium membrane.

[0021] The pressure swing adsorption hydrogen extraction unit adopts a four-tower pressure swing adsorption process, and is operated at an adsorption pressure of 0.8-1.2 MPa (a desorption pressure of 0.05-0.1 MPa) and an adsorption cycle of 60-90 seconds. By utilizing the difference in adsorption capacity of the adsorbent for different gases, the impurities such as CO, CO2 and N2 which are not completely adsorbed due to the reaction equilibrium and newly generated in the reforming reaction can be efficiently separated and removed, and the hydrogen volume fraction can be increased from 50%-60% to above 99.5% at one step.

[0022] The palladium membrane precision purification unit is connected to the pressure swing adsorption hydrogen extraction unit, and utilizes the unique dissolution-diffusion mechanism of hydrogen in palladium metal to achieve molecular-level screening of hydrogen. This step can completely remove the residual trace impurities (such as CO and CO2), and finally increase the purity of hydrogen to 99.99% and above, meeting the standard of electronic-grade hydrogen.

[0023] The synergistic design of the three-stage purification process provided by the application overcomes the limitations of single separation technology, and the purification process is stable, the product purity is high, and the energy consumption is low. In particular, by combining pressure swing adsorption and palladium membrane, the system operation cost is greatly reduced while ensuring high purity.

[0024] Further, the renewable energy driven heating device and the slag combustion heating device are configured to operate in a time coupling mode: during the day, renewable energy heating is mainly used, and at night or when the renewable energy is insufficient, the slag combustion heating is mainly used.

[0025] The application integrates the renewable energy driven heating device and the slag combustion heating device into a "time coupling" cooperative operation mode, optimally matches the intermittent renewable energy and the stable self-produced waste energy in the time dimension according to the natural law and the energy characteristics, to realize stable heating in all time periods and maximize energy and economic efficiency. During the day when the sunlight is sufficient, the system uses the renewable energy driven heating device as the main heat source, and preferentially consumes the low-cost solar energy and wind energy. When it is night, or when the renewable energy output power is lower than the power threshold due to extreme weather during the day, the system automatically switches to using the slag combustion heating device as the main heat source, and releases heat energy by burning the solid slag generated in the pyrolysis process. This energy supply strategy ensures the continuity of the production process through the "peak load shifting", and achieves the purpose of waste resource utilization and cost reduction and efficiency improvement. In addition, the cooperative control of the energy supply mode can ensure that the temperature fluctuation amplitude of the chamber of the key reaction unit is not greater than ±10℃, which provides a very important stable thermal environment for efficient hydrogen production reaction.

[0026] Preferably, the operation of the above-mentioned time-coupled mode is realized through a temperature-load linkage controller. The controller is electrically connected with the temperature sensor of each reaction system, the power transmitter of the renewable energy driven heat supply device, and the heat energy distribution assembly of the slag combustion heat supply device, respectively, for dynamically adjusting the output power of green electricity and accurately controlling the distribution amount of slag combustion heat energy according to the real-time temperature demand of each system and the real-time power generation of renewable energy, so as to realize smooth and stable switching and complementation between the two heat sources.

[0027] Preferably, the switching between the two functional modes is judged according to a quantitative power threshold, that is, when the real-time output power of renewable energy is lower than 60% of the total heat load of the system, the output of the slag combustion heat supply device is automatically started or increased.

[0028] Further, the slag combustion heat supply device further comprises a combustion supporting unit for controlling the excess air coefficient of slag combustion to be between 1.2 and 1.5. By controlling the excess air coefficient to be within the range of 1.2 to 1.5, the present application realizes sufficient and stable slag combustion, maintains a high furnace temperature, and guarantees a high heat energy output. If the coefficient is too low (<1.2), it will lead to insufficient air supply, insufficient slag combustion, and a large amount of carbon monoxide (CO) and unburned carbon black, which not only reduces the combustion efficiency and wastes fuel, but also causes environmental pollution; if the coefficient is too high (>1.5), it means that excessive cold air enters the combustion chamber, which will absorb and carry away a large amount of heat energy, resulting in a decrease in combustion temperature and a significant decrease in thermal efficiency, and at the same time, increasing the load of the flue gas treatment system.

[0029] Preferably, the combustion supporting unit comprises a combustion air fan which is in communication with the air inlet of the slag combustion chamber for introducing combustion air.

[0030] Preferably, temperature monitoring points and pressure monitoring points are provided in the slag combustion chamber. The temperature monitoring points are electrically connected with the frequency converter controller of the combustion air fan, constituting a closed-loop control: when the combustion chamber temperature is lower than 700℃, the combustion air fan speed is automatically increased to increase air supply and strengthen combustion. The pressure monitoring points are used to monitor the pressure at the top of the combustion chamber, and when the pressure is higher than 5kPa, a pressure relief valve is automatically opened, thereby ensuring the safety and stability of the combustion process.

[0031] Further, the renewable energy driven heat supply device further comprises a wind-solar complementary controller for preferentially scheduling solar power supply and automatically switching to wind power supply when the solar radiation intensity is lower than a set threshold.

[0032] To realize the high efficiency and stability of the renewable energy heating part in the above-mentioned time coupling mode, the present application provides a wind-solar complementary controller in the renewable energy driven heating device. The core purpose is to solve the inherent defects of intermittence and instability of single renewable energy, realize intelligent scheduling and efficient utilization of solar energy and wind energy, and improve the reliability and self-sustaining ability of the energy supply of the whole hydrogen production system. Specifically, the wind-solar complementary controller is electrically connected with the solar photovoltaic panel array and the wind turbine generator set, and follows the scheduling strategy of "solar energy first, wind energy as supplement". The controller monitors the solar radiation intensity in real time, and when the radiation is sufficient, the solar energy with higher conversion efficiency is preferentially used for power supply; when the radiation intensity is lower than the set threshold due to rain, night and other conditions, the controller automatically and seamlessly switches to the wind turbine generator set for power supply.

[0033] Preferably, the set threshold can be customized according to the annual average light and wind condition data of different regions to realize the optimization of local energy utilization. This fine intelligent control strategy is a powerful support for the top-level energy scheduling mode of the system. It can maximize the use of free natural resources, smooth the power output curve of renewable energy, significantly reduce the energy supply fluctuation caused by weather changes, ensure the provision of high-quality and stable power supply for the subsequent reaction unit, and also help to reduce the dependence on large-capacity energy storage equipment and control the overall system cost.

[0034] The technical solution adopted by the second purpose of the present application is to provide a dual-heating-mode biomass three-stage adsorption enhanced reforming hydrogen production method using the system of the first purpose of the present application, comprising the following steps: S1, pyrolyzing the biomass raw material through a pyrolysis reaction system to generate non-condensable gas and solid slag; S2, making the non-condensable gas enter a continuous adsorption enhanced fluidized bed system to contact with an adsorbent, and removing CO2 therefrom by on-line selective adsorption to obtain decarburized gas; S3, making the decarburized gas enter a continuous catalytic reforming fluidized bed system to contact with a catalyst, and performing directional bond breaking and small molecule reforming reaction of tar to obtain crude synthesis gas; S4, making the crude synthesis gas pass through a synthesis gas separation and purification system to obtain high-purity hydrogen product; In the method, a dual-source coupled heating system is used to provide heat energy for the pyrolysis, adsorption enhancement and catalytic reforming steps; wherein renewable energy driven heating device is preferentially used for heating during the day; at night or when the energy supply is insufficient, the heating device using slag combustion is switched to, and heating is performed by burning the slag generated in step S1.

[0035] The application provides a method for preparing hydrogen by a three-stage adsorption enhanced reforming of biomass in a double-heat-supply mode, which breaks through the efficiency and cost bottlenecks of traditional hydrogen production from biomass by synergizing the three-stage adsorption enhanced reforming reaction path with a double-source time sequence heat supply energy mode. In the three-stage adsorption enhanced reforming, the first pyrolysis provides raw gas for the system; the second stage of adsorption enhancement is a key innovative link, which removes CO2 by online selective adsorption, not only purifies the reaction gas, but also actively breaks the thermodynamic equilibrium of the subsequent reforming reaction, and drives the reaction to move in the direction of high hydrogen production from the perspective of chemical kinetics; the third stage of catalytic reforming is specially designed to overcome the problem of tar and complete the deep conversion of small molecules in the optimized gas atmosphere, and finally realizes the high-quality output of synthesis gas. At the same time, the double-source time sequence heat supply mode provides stable energy supply for the reaction chain in the whole time period at low cost. The mode matches the intermittent renewable energy and the solid waste (slag) produced in the system in the time dimension, realizes the maximum synergy of energy supply and process demand, external environment and internal materials, and significantly reduces the energy consumption cost and carbon footprint.

[0036] Further, in step S1, the pyrolysis reaction is completed at a temperature range of 500-800 DEG C, with inert gas being introduced and under stirring, so as to ensure the pyrolysis efficiency of the biomass raw material and the generation quality of the non-condensed gas.

[0037] Further, in steps S2 and S3, the continuous adsorption enhanced fluidized bed system and the continuous catalytic reforming fluidized bed system are provided with multiple layers of inclined staggered guide plates arranged in the reactors, so that the contact residence time of the non-condensed gas and the adsorbent or catalyst is controlled to be 3-5 seconds. The design optimizes the gas-solid contact efficiency, firstly aims to improve the adsorption efficiency of CO2 to more than 85%, and creates favorable conditions for the subsequent reforming reaction; secondly, the contact time of the catalyst and the decarburization gas is prolonged, so that the bond breaking reforming reaction is more complete and thorough.

[0038] Further, after steps S2 and S3, the waste adsorbent and the deactivated catalyst are transported to the corresponding regenerators for regeneration, and the regenerated adsorbent and catalyst are returned to the corresponding fluidized bed reactors. The in-situ recycling of the adsorbent and the catalyst can significantly prolong the service life of the materials to more than 50 cycles, so as to ensure that the system can realize continuous and stable operation for more than 8000 hours.

[0039] Preferably, the adsorbent in step S2 is a calcium-based or magnesium-based CO2 adsorbent; and the catalyst in step S3 is a Ni-based or Fe-based reforming catalyst.

[0040] Further, step S4 specifically comprises: S401, condensing and adsorbing the crude synthesis gas to remove tar and water vapor; S402, water washing and drying the gas after tar removal; S403, purifying the dried gas by four-tower pressure swing adsorption process under an adsorption pressure of 0.8-1.2 MPa and a desorption pressure of 0.05-0.1 MPa; S404, obtaining hydrogen product with a purity of ≥99.99% by palladium membrane precision filtration of the gas after pressure swing adsorption.

[0041] The synthetic gas separation and purification method provided by the application realizes deep purification of product gas with the lowest energy consumption through the synergy of "pretreatment-main separation-refining". The condensation and water washing as pretreatment can remove harmful tar and moisture; the four-tower pressure swing adsorption as the core separation section realizes efficient removal of impurity gas and preliminary concentration of hydrogen; finally, the palladium membrane precision filtration is adopted to utilize its ultra-high selectivity to hydrogen, so as to ensure that the product reaches the electronic grade purity. This combined process effectively avoids the high cost problem caused by single high-precision technology while ensuring extremely high product quality.

[0042] Preferably, in step S402, the water washing is realized by countercurrent spraying in a water washing tank filled with ceramic Raschig ring fillers; and the drying adopts 4A or 13X type molecular sieve drier to reduce the gas dew point to below -40℃.

[0043] Further, before the slag generated in the combustion step S1 is burned, it is first crushed to a particle size of ≤10mm; and the slag combustion process realizes automatic adjustment of combustion air volume and overpressure relief by monitoring the temperature and pressure of the combustion chamber, so as to ensure the operation safety.

[0044] Compared with the prior art, the application has the following advantages: (1) The system for preparing hydrogen by biomass three-stage adsorption enhanced reforming in a double-heat-supply mode provided by the application solves the core problems of equipment dispersion, high energy consumption and difficulty in continuous and stable operation in the prior art through a highly integrated integrated architecture. The system organically integrates the modules of feeding, pyrolysis, adsorption enhancement, catalytic reforming, separation and purification, and double-source heat supply, forms a closely connected material and energy closed loop, not only significantly reduces the transmission loss and equipment area of the system, but also prolongs the service life of the key materials through the in-situ regeneration and circulation design of the adsorbent and the catalyst, and ensures that the device can realize long-period continuous operation. In addition, the system innovatively adopts a heat supply mode complementary to renewable energy and self-produced slag combustion, realizes the space-time matching and cascade utilization of energy, greatly reduces the dependence on external energy and operating cost, and completely realizes the recycling of solid waste, showing excellent economy and environmental value.

[0045] (2) This invention provides a method for producing hydrogen from biomass through a three-stage adsorption-enhanced reforming process using a dual-heating mode, constructing a three-stage reaction pathway with sequential synergy between adsorption enhancement and catalytic reforming. This method actively breaks the thermodynamic equilibrium limitations of traditional reactions by removing CO2 through online adsorption, thereby driving the hydrogen production reaction in the forward direction and significantly improving the hydrogen yield. Simultaneously, this method specifically performs catalytic cracking and deep reforming of tar, combined with a multi-stage purification process, enabling the stable production of ultra-high purity hydrogen that meets the needs of high-end applications. The entire process is deeply synergistic with the dual-source sequential heating mode, enabling biomass resources to be efficiently and economically converted into high-value hydrogen energy products, providing a solid technical foundation for the industrial-scale promotion of biomass hydrogen production. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of a biomass three-stage adsorption-enhanced reforming hydrogen production system with dual heating modes provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the gas input sleeve and stirring device of the pyrolysis reactor in the system provided in the embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the adsorbent and catalyst regenerator in the system provided in the embodiment of the present invention; The system comprises: 1-Biomass feedstock inlet; 101-Screw conveyor; 2-Pyrolysis reactor; 201-Stirring device; 202-Slag outlet; 203-Non-condensable gas insulation pipeline; 3-First fluidized bed reactor; 301-High-speed gas nozzle; 302-Solid bed; 303-Baffle / partition; 4-First cyclone separator; 5-Adsorbent regenerator; 501-Carrier gas inlet; 502-Gas outlet pipeline; 503-Partition; 504-Adsorbent return channel; 6-Second fluidized bed reactor; 601-High-speed gas nozzle; 602-Solid bed; 603-Baffle / partition; 7-Second cyclone separator; 8-Catalyst regenerator; 9-Synthesis gas separation and purification system; 901-Crude synthesis gas inlet; 902-High-purity hydrogen outlet; 903-Dehydrogenated mixed gas outlet. Detailed Implementation

[0047] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0049] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0050] Example 1 This embodiment provides a system for hydrogen production from biomass through a three-stage adsorption-enhanced reforming process with a dual heating mode. Its overall structural schematic diagram is shown below. Figure 1 As shown, it mainly includes a biomass feeding system, a pyrolysis reaction system, a continuous adsorption enhanced fluidized bed system, a continuous catalytic reforming fluidized bed system, a syngas separation and purification system, and a dual-source coupled heating system, which are connected in sequence and operate in coordination.

[0051] The biomass feeding system includes a sealed silo 1. The silo 1 has a biomass feed inlet 101 with a flow control valve at the top and a feed outlet with a screw conveyor mechanism 102 at the bottom. The screw conveyor mechanism 102 uniformly conveys the biomass upwards. The feed outlet is connected to the feed inlet of the pyrolysis reaction system via a heat-insulated conveying pipeline. Inert gases such as nitrogen are introduced into this pipeline as carrier gases to assist the feed material in its descent.

[0052] The pyrolysis reaction system includes a vertical pyrolysis reactor 2. The outer wall of the reactor 2 is covered with an electric heating jacket, which is electrically connected to a heating controller with a temperature sensor. The reactor 2 has a non-condensable gas outlet at the top, an inert gas input sleeve in the middle, and a stirring device 201. The stirring device agitates the biomass feedstock during the pyrolysis reaction, improving pyrolysis efficiency. The reactor 2 has a slag discharge outlet 202 with a gate valve at the bottom. The heating controller precisely controls the temperature of the reactor 2 chamber to the process range of 500-800℃ based on temperature sensor feedback, driving the biomass feedstock to undergo pyrolysis and generating non-condensable gas containing H2, CO, CO2, CH4, and tar components, as well as solid slag. The non-condensable gas outlet is connected to a continuous adsorption-enhanced fluidized bed system via an insulated pipe 203, and the slag discharge outlet 202 is connected to a dual-source coupled heating system via a sealed pipe.

[0053] The continuous adsorption enhanced fluidized bed system includes a vertical first fluidized bed reactor 3. The first fluidized bed reactor 3 has an adsorbent inlet with a metering feeder on the side of its solid bed 302, an outlet for gaseous adsorption products and solid waste adsorbent on its upper wall, and a high-speed gas nozzle 301 at its bottom. The gas ejected from the high-speed gas nozzle 301 is non-condensable gas from the pyrolysis reactor 2, which passes through the solid bed 302 at high speed, causing the calcium-based or magnesium-based CO2 adsorbent to enter a fluidized state. The first fluidized bed reactor 3 selectively adsorbs CO2 from the non-condensable gas online using the adsorbent, generating gaseous adsorption products with a CO2 content ≤5%, mainly a mixture of H2, CO, and CH4, along with solid waste adsorbent, which are discharged from their respective outlets. The system is externally equipped with a cyclone separator 4 and a continuous adsorbent regenerator 5. The adsorbent regenerator 5 is connected to the solid outlet of the cyclone separator 4 via sealed pipelines for pyrolysis activation of the waste adsorbent. The regenerated adsorbent is then fed back to the first fluidized bed reactor 3 via a quantitative feeder.

[0054] The continuous catalytic reforming fluidized bed system includes a vertical second fluidized bed reactor 6. The second fluidized bed reactor 6 has a catalyst inlet with a pneumatic conveying mechanism on the side of its solid bed 602, a syngas and deactivated catalyst outlet on its upper wall, and a high-speed gas nozzle 601 at its bottom. The gas ejected from the high-speed gas nozzle 601 is the gas-phase adsorption product from the first fluidized bed reactor 3. The gas passes through the solid bed 602 at high speed, causing the Ni-based or Fe-based reforming catalyst to enter a fluidized state. The temperature of the chamber of the second fluidized bed reactor 6 is controlled to 600-700℃ by a heating system. The catalyst performs directional bond breaking of large molecular tar CC bonds and CO bond cleavage, and small molecule secondary reforming reactions on the gas-phase adsorption products, generating syngas with an H2 volume fraction ≥50% and deactivated catalyst. The system is also externally equipped with a cyclone separator 7 and a continuous catalyst regenerator 8. The catalyst regenerator 8 is connected to the solid outlet of the cyclone separator 7 via sealed pipelines to reactivate the deactivated catalyst. The regenerated catalyst is then fed back to the second fluidized bed reactor 6 via a metering feeder.

[0055] The syngas separation and purification system 9 includes a condenser, a washing tank, a drying chamber, a pressure swing adsorption (PSA) separation chamber, and a precision purification chamber connected in series. The condenser is a jacketed structure with a syngas inlet and an organic adsorbent (activated carbon particles) inlet at the top, a condensate liquid product (tar and water mixture) outlet at the bottom, and a non-condensable gas outlet on the upper side wall. Cooling water at -5 to 10°C is circulated within the jacket to synergistically remove most of the tar and water vapor from the syngas. The washing tank is filled with ceramic Raschig ring packing, and dust and trace amounts of tar are removed by counter-current spraying. The drying chamber contains 4A or 13X type molecular sieve desiccant for deep dehydration to a dew point ≤ -40°C. The PSA separation chamber uses an activated carbon-molecular sieve composite adsorbent to separate impurities such as CO, CO2, and N2. The precision purification chamber uses a palladium membrane filter to ultimately obtain hydrogen product with a purity ≥ 99.99%.

[0056] The dual-source coupled heating system includes a renewable energy-driven heating device and a slag combustion heating device. The renewable energy-driven heating device collects and utilizes electrical energy generated from renewable energy sources such as solar and wind power. The energy collection unit includes at least a solar photovoltaic panel array and a small horizontal-axis wind turbine generator to power the electric heating components in the pyrolysis reaction system, the continuous adsorption-enhanced fluidized bed system, and the continuous catalytic reforming fluidized bed system. The slag combustion heating device has its inlet connected to the slag outlet 202 of the pyrolysis reactor 2 via a sealed pipeline. The slag combustion chamber is a horizontal chain grate combustion chamber, with a flue gas purification unit (including a cyclone dust collector and a desulfurization tower) at the top to release heat energy from the combustion of the pyrolysis slag, and provides a heat source to each reaction system via a heat distribution pipeline.

[0057] The system is configured to operate in a time-coupled mode: during the day, it prioritizes using renewable energy to power the heating devices; at night or when the energy supply is insufficient, it automatically switches to using slag combustion heating devices for heating.

[0058] Example 2 Based on Example 1, this embodiment optimizes the design of the internal structure of the adsorption fluidized bed, the specific implementation of the regeneration circuit, and the syngas purification chain.

[0059] In this embodiment, the first fluidized bed reactor 3 of the continuous adsorption enhanced fluidized bed system is equipped with multiple layers of guide plates 303. The guide plates 303 are arranged at a 45° inclination angle, and adjacent guide plates are staggered. This structure is used to optimize the contact path between the airflow and the adsorbent in the bed, extending the gas residence time to 3-5 seconds, thereby increasing the CO2 adsorption efficiency to over 85%.

[0060] The adsorbent regenerator 5 is equipped with a heating component and an inert gas purging unit. During regeneration, the temperature is precisely controlled within the range of 900-1000℃, and inert gases such as nitrogen are introduced to pyrolyze and activate the waste calcium-based or magnesium-based adsorbent, restoring its adsorption capacity.

[0061] The second fluidized bed reactor 6 of the continuous catalytic reforming fluidized bed system is also equipped with multi-layer guide plates 603, with a structure identical to the multi-layer guide plates 303 in the first fluidized bed reactor 3. This structure aims to prolong the contact time between the catalyst and the decarbonization gas, making the bond-breaking reforming reaction more complete and thorough.

[0062] The catalyst regenerator 8 is also equipped with a heating component and an inert gas purging unit. During regeneration, the temperature is precisely controlled within the range of 700-800℃, and inert gases such as nitrogen are introduced to regenerate the deactivated Ni-based or Fe-based catalyst by carbonization, thereby restoring its catalytic activity.

[0063] The syngas separation and purification system 9 includes a condensation and tar removal unit, a water washing tank, a drying chamber, a pressure swing adsorption (PSA) hydrogen extraction unit employing a four-tower PSA process, and a palladium membrane precision purification unit, connected in sequence. The condensation and tar removal unit is a jacketed condenser, with cooling water at -5 to 10°C circulated within the jacket, and activated carbon adsorbent added concurrently to capture and remove residual tar and water vapor that have not been converted or recondensed after catalytic reforming. The water washing tank is filled with packing materials such as ceramic Raschig rings, and further removes dust and trace amounts of tar from the gas through countercurrent spraying. The drying chamber contains molecular sieve desiccant for deep dehydration, lowering the gas dew point to below -40°C to protect the subsequent adsorbent and palladium membrane. The PSA hydrogen extraction unit has an adsorption pressure of 0.8-1.2 MPa, a desorption pressure of 0.05-0.1 MPa, and an adsorption cycle of 60-90 s, used to increase the volume fraction of the mixed gas to over 99.5%.

[0064] Example 3 Based on Example 2, this embodiment features a refined design and intelligent control of the dual-source coupled heating system, and demonstrates the comprehensive performance of the integrated system.

[0065] In this embodiment, the renewable energy-driven heating device further includes a wind-solar hybrid controller. The wind-solar hybrid controller is electrically connected to a solar photovoltaic panel array using monocrystalline silicon modules (photovoltaic conversion efficiency ≥23%), a small horizontal-axis wind turbine generator set containing fiberglass wind turbine blades (diameter 3-5m), and a permanent magnet synchronous generator, respectively, for prioritizing the power output of the solar photovoltaic panel array; when the solar irradiance is detected to be below 200 W / m², the controller will be activated. 2When a set threshold is reached, the system automatically switches to wind turbine power supply to ensure stable output power of the energy harvesting unit. The renewable energy-driven heating device also includes an energy storage unit (a lithium battery energy storage cabinet with a capacity of ≥50kWh) and an energy transmitter (including a dedicated cable transmission line with overload protection and a transformer).

[0066] The slag combustion heating device also includes a slag conveying pipeline, a slag crushing unit, and a combustion-supporting fan. The slag conveying pipeline is a sealed pipeline with a scraper conveyor; its input end is connected to the slag outlet 202 of the pyrolysis reactor 2, and its output end is sequentially connected to the slag crushing unit and the feed inlet of the slag combustion chamber. The slag crushing unit is used to crush the slag into uniform particles with a particle size ≤10mm to facilitate complete combustion. The combustion-supporting fan is connected to the air inlet of the slag combustion chamber to introduce combustion air, and the excess air coefficient for slag combustion is precisely controlled between 1.2 and 1.5 by a frequency converter to ensure complete and efficient combustion. Furthermore, the slag combustion chamber is equipped with temperature and pressure monitoring points. When the combustion chamber temperature is below 700℃, the system automatically increases the speed of the combustion-supporting fan; when the combustion chamber pressure is above 5kPa, the pressure relief valve automatically opens to ensure the safety and stability of the combustion process.

[0067] The integrated system described in this embodiment connects the renewable energy-driven heating device and the slag combustion heating device through a heat distribution component, forming a precise dual-source complementary heating link. The heat distribution component includes stainless steel heat distribution pipes, plate heat exchange units embedded in each reaction system, and flow regulating valves. The plate heat exchange units are made of titanium alloy for corrosion resistance and extended service life. The heat exchange area of ​​the plate heat exchange units is designed according to the heat load requirements of each system; for example, the heat exchange area of ​​the plate heat exchange unit in the pyrolysis reaction system is 5-8 m². 2 The continuous adsorption enhanced fluidized bed system has a depth of 8-12 m. 2 The continuous catalytic reforming fluidized bed system has a capacity of 10-15 m. 2 .

[0068] The system is configured to operate in the following mode: during the day (6:00-18:00), heating is primarily provided by green electricity driven by renewable energy sources. When the output power of green electricity falls below 60% of the total system heat load, the slag combustion heating system automatically activates to supplement energy. At night (18:00-6:00 the next day), the system switches to primarily using the slag combustion heating system. This mode ensures that the temperature fluctuation range of each reactor chamber does not exceed ±10℃.

[0069] Testing has shown that the complete system constructed in this embodiment can achieve the following technical effects: hydrogen yield is increased to over 45%, and hydrogen purity is stabilized at 99.99% or higher; the adsorbent and catalyst can be regenerated in situ, and their cycle life can reach more than 50 times. The system can operate for more than 8,000 hours per year, realizing efficient, stable, and continuous industrial hydrogen production.

[0070] Example 4 This embodiment provides a method for hydrogen production from biomass using a dual-heating mode with three-stage adsorption-enhanced reforming of the system described in Embodiment 3. The method specifically includes the following steps: Step 1: Biomass feedstock feeding, conveying and pyrolysis Biomass feedstock is fed into the silo 1 of the biomass feeding system through the top inlet 101, and the feeding rate is controlled. The feedstock is then stably transported to the pyrolysis reactor 2 of the pyrolysis reaction system via the bottom screw conveyor 102 and the insulated pipeline.

[0071] The electric heating jacket and heating controller on the outer wall of pyrolysis reactor 2 are activated to regulate the reactor chamber temperature to the pyrolysis process range of 500-800℃. Simultaneously, inert gas enters through the gap between the inlet sleeve and the stirring device 201. The stirring device agitates the biomass feedstock during the pyrolysis reaction to improve pyrolysis efficiency. This process generates non-condensable gas containing H2, CO, CO2, CH4, and tar components, as well as solid slag. The non-condensable gas is transported to the continuous adsorption enhanced fluidized bed system via the insulated pipe 203 at the top of the reactor; the slag is discharged through the slag outlet 202 with a gate valve at the bottom and transported to the slag combustion chamber of the heating system.

[0072] Step 2: Enhanced Non-condensable Gas Adsorption Treatment The non-condensable gas generated in step 1 is introduced at high speed into the first fluidized bed reactor 3 of the continuous adsorption enhanced fluidized bed system through a high-speed gas nozzle 301 at the bottom. Simultaneously, calcium-based or magnesium-based CO2 adsorbent is added through the adsorbent inlet on the side of the solid bed 302. The high-speed gas flow through the solid bed fluidizes the adsorbent. Under the optimized effect of the staggered guide plates 303 at a 45° angle, the non-condensable gas comes into full contact with the adsorbent, and the residence time is controlled to be 3-5 seconds. CO2 is selectively adsorbed and removed online to obtain decarbonized gas (CO2 content ≤ 5%).

[0073] The gas-phase adsorption products and solid-phase waste adsorbent enter the cyclone separator 4 through the outlet for gas-solid separation. The separated decarbonized gas enters the subsequent system, while the solid-phase waste adsorbent falls into the adsorbent regenerator 5. In the adsorbent regenerator 5, inert gas is introduced through the carrier gas inlet 501 to blow the adsorbent particles and control the temperature at 900-1000℃ for pyrolysis activation. The regenerated and activated adsorbent is returned to the solid bed of the first fluidized bed reactor 3 through the channel 504 for recycling.

[0074] Step 3: Catalytic reforming of gas-phase adsorption products The decarbonized gas generated in step 2 is introduced into the second fluidized bed reactor 6 of the continuous catalytic reforming fluidized bed system through a high-speed gas nozzle 601 at the bottom. Simultaneously, a nickel-based or iron-based reforming catalyst is added through the catalyst inlet on the side of the solid bed 602. The gas passes through the solid bed at high speed, causing the catalyst to enter a fluidized state. The reactor chamber temperature is controlled to the catalytic reforming process range of 600-700℃ by the heating system. Under the action of the catalyst, the decarbonized gas undergoes directional bond breaking of large tar molecules (CC and CO bond cleavage) and secondary reforming reactions with small molecules, generating syngas with a H2 volume fraction ≥50%.

[0075] Syngas and deactivated catalyst enter cyclone separator 7 for gas-solid separation. The separated syngas enters the subsequent purification system, while the solid-phase deactivated catalyst falls into catalyst regenerator 8. In catalyst regenerator 8, inert gas is introduced through the carrier gas inlet to blow away catalyst particles and the temperature is controlled at 700-800℃ for carbonization regeneration. The regenerated catalyst is returned to the solid bed of the second fluidized bed reactor 6 for recycling.

[0076] Step 4: Syngas washing and separation purification Step 401, condensation and tar removal: The syngas generated in step S3 is introduced into a condensation tank, and cooling water at -5 to 10°C is introduced into the jacket of the condensation tank. Activated carbon adsorbent is added in conjunction with the condensation. Through the synergistic effect of condensation and adsorption, most of the tar and water vapor in the syngas are removed, and the condensed liquid product and non-condensable gas are separated.

[0077] Step 402, Washing and Drying: The non-condensable gas is passed into a washing tank filled with ceramic Raschig ring packing, and dust and trace amounts of tar are further removed by counter-current spraying; then the gas is passed into a drying chamber, where it is deeply dehydrated by molecular sieve desiccant, and the gas dew point is reduced to below -40°C.

[0078] Step 403, Pressure Swing Adsorption for Hydrogen Extraction: The dried gas is introduced into the pressure swing adsorption separation chamber. A four-tower pressure swing adsorption process is used, operating at an adsorption pressure of 0.8-1.2 MPa and a desorption pressure of 0.05-0.1 MPa to separate and remove impurities such as CO, CO2, and N2, increasing the hydrogen gas integral to over 99.5%.

[0079] Step 404, Palladium membrane precision filtration: The gas after pressure swing adsorption is passed into the precision purification chamber and sieved at the molecular level through the palladium membrane filter to completely remove residual trace impurities and obtain hydrogen product with a purity ≥99.99%.

[0080] Throughout the entire method execution process, the dual-source coupled heating system provides thermal energy for steps S1, S2, and S3. Its regulation process is based on the system configuration set in Example 3, and specifically operates as follows: During the daytime, the renewable energy-driven heating device is activated first for heating.

[0081] At night or when renewable energy supply is insufficient, the system automatically switches to the slag combustion heating device to provide heat through the slag produced in combustion step S1.

[0082] During this process, the built-in temperature control mechanism ensures that the temperature of each reactor chamber is kept stable within the preset process range.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and scope of protection of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the scope of protection of the present invention.

Claims

1. A system for hydrogen production from biomass using a dual-heating mode with three-stage adsorption-enhanced reforming, characterized in that, It includes a biomass feeding system, a pyrolysis reaction system, a continuous adsorption enhanced fluidized bed system, a continuous catalytic reforming fluidized bed system, a syngas separation and purification system, and a dual-source coupled heating system connected in sequence. The continuous adsorption enhanced fluidized bed system is used to introduce non-condensable gas from the pyrolysis reaction system and selectively remove CO2 online through the fluidized adsorbent; the system is also equipped with an adsorbent regeneration and circulation loop for regenerating and reusing the adsorbent. The continuous catalytic reforming fluidized bed system is used to introduce gas from the continuous adsorption enhanced fluidized bed system, and to carry out directional bond breaking and small molecule reforming reaction of tar through the fluidized catalyst; the system is also equipped with a catalyst regeneration and circulation loop for catalyst regeneration and reuse. The dual-source coupled heating system includes a renewable energy-driven heating device and a slag combustion heating device; the renewable energy-driven heating device uses renewable energy to heat each reaction system; the slag combustion heating device is connected to the slag discharge port of the pyrolysis reaction system and is used to burn pyrolysis slag and heat each reaction system.

2. The system according to claim 1, characterized in that, Both the continuous adsorption enhanced fluidized bed system and the continuous catalytic reforming fluidized bed system are equipped with multiple layers of inclined and staggered guide plates in the reactor to optimize gas-solid contact and prolong gas residence time.

3. The system according to claim 1, characterized in that, The adsorbent regeneration and circulation loop and / or catalyst regeneration and circulation loop are provided with a regenerator; the regenerator is connected to the corresponding fluidized bed through a separation device, and its interior is provided with a heating component and an inert gas purging unit for realizing the regeneration function.

4. The system according to claim 1, characterized in that, The syngas separation and purification system includes a condensation tar removal unit, a pressure swing adsorption hydrogen extraction unit, and a palladium membrane precision purification unit connected in sequence.

5. The system according to claim 1, characterized in that, The renewable energy-driven heating device and the slag combustion heating device are configured to operate in a time-coupled mode: during the day, renewable energy heating is the main method; at night or when renewable energy supply is insufficient, the system switches to slag combustion heating as the main method.

6. The system according to claim 1, characterized in that, The slag combustion heating device also includes a combustion-aiding unit for controlling the excess air coefficient of slag combustion to be between 1.2 and 1.

5.

7. The system according to claim 1, characterized in that, The renewable energy-driven heating device also includes a wind-solar hybrid controller, which prioritizes solar power supply and automatically switches to wind power supply when the solar irradiance is below a set threshold.

8. A method for producing hydrogen from biomass using a dual-heating mode of biomass three-stage adsorption-enhanced reforming employing the system described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Biomass raw materials are pyrolyzed through a pyrolysis reaction system to generate non-condensable gas and solid slag. S2. The non-condensable gas is introduced into a continuous adsorption enhanced fluidized bed system to contact the adsorbent, and CO2 is selectively adsorbed and removed online to obtain decarbonized gas. S3. The decarbonized gas is introduced into a continuous catalytic reforming fluidized bed system to contact the catalyst, and the directional bond breaking and small molecule reforming reaction of tar is carried out to obtain crude syngas. S4. The crude syngas is processed by a syngas separation and purification system to obtain a high-purity hydrogen product; In the method, a dual-source coupled heating system is used to provide heat energy for the pyrolysis, adsorption enhancement and catalytic reforming steps; during the day, renewable energy is used to drive the heating device for heating; at night or when the energy supply is insufficient, the system switches to a slag combustion heating device to provide heat through the slag produced in the combustion step S1.

9. The method according to claim 8, characterized in that, In steps S2 and S3, the reactors of the continuous adsorption enhanced fluidized bed system and the continuous catalytic reforming fluidized bed system are equipped with multiple layers of inclined staggered guide plates to control the contact residence time between the non-condensable gas and the adsorbent and catalyst to 3-5 seconds. After steps S2 and S3, the waste adsorbent and deactivated catalyst are respectively transported to the corresponding regenerators for regeneration, and the regenerated adsorbent and catalyst are returned to the corresponding fluidized bed reactor.

10. The method according to claim 8, characterized in that, Step S4 specifically includes: S401. The crude syngas is condensed and adsorbed to remove tar and water vapor; S402. The gas after tar removal is washed with water and dried. S403. A four-tower pressure swing adsorption process is used to purify the dried gas at an adsorption pressure of 0.8-1.2 MPa and a desorption pressure of 0.05-0.1 MPa. S404. The gas after pressure swing adsorption is subjected to palladium membrane precision filtration to obtain hydrogen product with a purity of ≥99.99%.

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