Method and system for preparing hydrogen-rich syngas by coupling biomass pyrolysis, volatile chemical looping reforming and staged regeneration of pyrolysis gas

Abstract

The application discloses a method and system for preparing hydrogen-rich synthesis gas by coupling biomass pyrolysis volatile chemical chain reforming with pyrolysis gas staged regeneration, and belongs to the technical field of high-value conversion of biomass. The method comprises the following steps: biomass pyrolysis is carried out under the action of a carrier gas by taking an inert medium as a heating medium, and pyrolysis volatiles and pyrolysis coke are obtained; the pyrolysis volatiles are separated into large molecules and small molecules by a spray tower; a reforming reactor is used for reforming reaction of oxygen carriers and volatile large molecules to generate synthesis gas; the pyrolysis coke is combusted under the action of oxygen-poor air to generate combustion flue gas and heat the inert medium; the pyrolysis volatile small molecules and the combustion flue gas are used for primary regeneration of the oxygen carriers, and the obtained gas is used for heating of the pyrolysis carrier gas; and air is used for complete regeneration of the oxygen carriers, and the obtained oxygen carriers are recycled into the reforming reactor. The method realizes production of synthesis gas and utilization of carbon dioxide, realizes heat coupling, and realizes efficient conversion of high-value biomass.

Description

Technical Field

[0001] This invention belongs to the field of biomass high-value conversion technology, specifically relating to a method and system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas. Background Technology

[0002] Hydrogen-rich syngas, as an important energy carrier, can be widely used in energy storage, environmental protection, and chemical production, and is a crucial intermediate in the production of fuels and chemicals. Biomass, as the only dual carrier of green hydrogen and green carbon, boasts abundant reserves and diverse sources, and its efficient development and utilization hold immense potential for addressing energy challenges. Using biomass resources as a raw material to produce hydrogen-rich syngas is of great significance. Typically, biomass can be converted into hydrogen-rich syngas through gasification technology; however, the biomass gasification process struggles to achieve targeted control of the key reaction (hydrogen production), and the presence of gasification tar causes blockages and corrosion in downstream pipelines, affecting equipment lifespan and gasification efficiency.

[0003] Biomass chemical looping gasification technology based on a decoupling strategy separates the complex gasification process into biomass pyrolysis and pyrolysis volatiles chemical looping reforming processes. Through controlled oxygen release and a recyclable oxygen carrier, the directional control of biomass pyrolysis volatiles towards hydrogen-rich syngas can be achieved. The main process involves biomass passing through a pyrolysis reactor to produce pyrolysis volatiles and pyrolysis coke. The generated volatiles then enter a reforming reactor where they undergo partial oxidation with the oxygen carrier. During this process, CH and CO bonds in the volatiles break and recombine, generating hydrogen-rich syngas. Simultaneously, the pyrolysis coke and the reacted oxygen carrier enter a regeneration reactor to regenerate the oxygen carrier. By controlling key reaction processes, in-situ conversion of biomass gasification tar and efficient production of hydrogen-rich syngas can be achieved. However, biomass pyrolysis volatiles exhibit diversity in type and content. In actual volatiles, heavy condensable volatile components (large volatile molecules) coexist with light gases such as CH4, CO2, H2, and CO (small volatile molecules), leading to strong coupling of reaction pathways and competitive occupation of active sites, posing challenges to the product selectivity of syngas. Among these, endogenous CO2, comprising approximately 30 vol% of the small volatile molecules, plays a dual and ambiguous role. On the one hand, it competes with hydrocarbons such as CH4 for active sites, inhibiting efficient conversion of volatiles and potentially altering the redox behavior and structure of the oxygen carrier. On the other hand, endogenous CO2, as a mild oxidant, can be used for primary regeneration of the oxygen carrier and as a carbon source for methane dry reforming, enabling lattice oxygen recovery and syngas co-production. The presence of this endogenous CO2 presents a challenge to the chemical chaining of hydrogen production from volatiles. Chinese patent application CN114350411B discloses a method for producing hydrogen-rich syngas through chemical loop reforming of carbon-based solid fuels. In this method, all volatiles generated from biomass pyrolysis are fed into a reforming reactor to react with an oxygen carrier, while coke is fed into a regeneration reactor for combustion and oxygen carrier regeneration. However, this technology does not separate the pyrolysis volatiles. The endogenous CO2 in the volatiles competes with hydrocarbons such as CH4 for active sites on the oxygen carrier, inhibiting the efficient conversion of large volatile molecules, leading to unstable syngas selectivity and ineffective CO2 utilization. Chinese patent application CN115321478A discloses a biomass pyrolysis chemical loop hydrogen production process that separates the pyrolysis gas and solids for separate processing, but this still does not solve the problems of CO2 interference and resource utilization in the volatiles, resulting in low system thermal efficiency.

[0004] In summary, in existing chemical reforming processes, endogenous CO2 in pyrolysis volatiles interferes with the reforming reaction and wastes carbon resources. There is an urgent need to find a chemical reforming process for biomass pyrolysis volatiles coupled with a staged regeneration process for pyrolysis gas. This process would separate the pyrolysis volatiles into large and small molecules, utilize the CO2 in the smaller molecules as an oxygen carrier for regeneration, and couple this process with a dry reforming reaction. This would avoid CO2 interference with the reforming reaction and achieve its resource utilization. Summary of the Invention In order to overcome the shortcomings of the prior art, the present invention aims to provide a method and system for preparing hydrogen-rich syngas by chemical chain reforming coupled with staged regeneration of pyrolysis gas from biomass pyrolysis volatiles, so as to solve the technical problem of interference of endogenous CO2 in pyrolysis volatiles on the reforming reaction and realize its resource utilization.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a method for preparing hydrogen-rich syngas through staged regeneration of biomass pyrolysis volatile matter via chemical chain reforming coupled with pyrolysis gas, comprising the following steps: S1. Biomass undergoes pyrolysis under the action of an inert fluidizing medium and a heat transfer medium, producing pyrolysis volatiles and pyrolysis coke. The separation of pyrolysis volatiles and pyrolysis coke is achieved through gas-solid separation. S2. The pyrolysis volatiles obtained in S1 are condensed and separated into large volatile molecules and small volatile molecules. S3. The volatile macromolecules obtained in S2 are fed together with the superheated steam generated by the steam generator and obtained by heat exchange into the reforming reaction zone, where they undergo a partial oxidation reaction with the oxygen carrier to generate hydrogen-rich syngas and reduced oxygen carrier. S4. The pyrolytic coke obtained in S1 is burned with oxygen-deficient air in the combustion reaction zone to generate combustion flue gas, which is then heat-exchanged with the steam generated by the steam generator to obtain superheated steam. The superheated steam is used in S3. S5. The volatile small molecules obtained from S2 and the combustion flue gas obtained from S4 are fed into the primary regeneration reaction zone and come into contact with the reduced oxygen carrier. The weak oxidizing property of CO2 is used to perform primary regeneration of the reduced oxygen carrier. At the same time, the CO2 in the volatile small molecules undergoes a dry reforming reaction with CH4 to generate carbon-rich gas and primary regenerated oxygen carrier. S6. Pass the primary regenerated oxygen carrier obtained in S5 into the secondary regeneration reaction zone to react with air or oxygen to achieve complete regeneration of the oxygen carrier, and obtain oxidized oxygen carrier and oxygen-deficient air. The oxygen-deficient air is used for S4. S7. The oxidized oxygen carrier obtained in S6 is recycled back to S3.

[0006] Preferably, in S1, the pyrolysis reaction temperature is 400-600℃; the biomass is wheat straw, reeds, microalgae, corn straw, rice husks or pine sawdust, and the particle size of the biomass is 0.3-1.5 mm; the heat transfer medium is sand or silica. In S2, the condensing medium for the condensation process is liquid water at 20-40℃.

[0007] Preferably, in S3, the temperature of the partial oxidation reaction is 700-900℃, the oxygen carrier is Fe2O3 or NiFe2O4, and the particle size of the oxygen carrier is 0.1-0.45 mm; the temperature of the superheated steam is 150-300℃.

[0008] Preferably, in S5, the temperature of the primary regeneration reaction zone is 50-100°C higher than the temperature of the reforming reaction zone in S3; In S6, the temperature of the secondary regeneration reaction zone is 50-100℃ higher than that of the primary regeneration reaction zone in S5.

[0009] Preferably, in S5, the carbon-rich gas is used to preheat the inert fluidizing medium in S1 after heat exchange.

[0010] This invention also discloses a system for preparing hydrogen-rich syngas by coupling pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, used to realize the above-mentioned method for preparing hydrogen-rich syngas by coupling pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, comprising: a pyrolysis reactor, a spray tower, a reforming reactor, a pyrolysis coke combustion reactor, a primary regeneration reactor, and a secondary regeneration reactor. The pyrolysis reactor is equipped with a volatile matter outlet and a pyrolysis coke outlet; The inlet of the spray tower is connected to the volatile matter outlet of the pyrolysis reactor. The spray tower is equipped with a small volatile molecule gas outlet and a large volatile molecule liquid outlet. The reforming reactor is equipped with a volatile matter inlet, a steam inlet, an oxygen carrier inlet, a syngas outlet, and an oxygen carrier outlet. The volatile matter inlet of the reforming reactor is connected to the volatile matter macromolecular liquid outlet of the spray tower. The pyrolysis coke combustion reactor is equipped with a pyrolysis coke inlet, an oxygen-deficient air inlet, a steam inlet, a superheated steam outlet, and a combustion flue gas outlet. The pyrolysis coke inlet of the pyrolysis coke combustion reactor is connected to the pyrolysis coke outlet of the pyrolysis reactor; the superheated steam outlet of the pyrolysis coke combustion reactor is connected to the steam inlet of the reforming reactor. The primary regeneration reactor is equipped with a gas inlet, an oxygen carrier inlet, and an oxygen carrier outlet. The gas inlet of the primary regeneration reactor is connected to the volatile small molecule gas outlet of the spray tower and the combustion flue gas outlet of the pyrolysis coke combustion reactor, respectively. The oxygen carrier inlet of the primary regeneration reactor is connected to the oxygen carrier outlet of the reforming reactor. The secondary regeneration reactor is equipped with an oxygen carrier inlet, an air inlet, a regenerated oxygen carrier outlet, and an oxygen-deficient air outlet. The oxygen carrier inlet of the secondary regeneration reactor is connected to the oxygen carrier outlet of the primary regeneration reactor, the regenerated oxygen carrier outlet of the secondary regeneration reactor is connected to the oxygen carrier inlet of the reforming reactor, and the oxygen-deficient air outlet of the secondary regeneration reactor is connected to the oxygen-deficient air inlet of the pyrolysis coke combustion reactor.

[0011] Preferably, the spray tower has a small volatile molecule gas outlet at the top, a large volatile molecule liquid outlet at the bottom, and a spray medium inlet on the side.

[0012] Preferably, it also includes a gas heat exchanger, the inlet of which is connected to the gas outlet of the primary regeneration reactor, and the outlet of which is connected to the inert carrier gas inlet of the pyrolysis reactor.

[0013] Preferably, the pyrolysis reactor is a fluidized bed reactor, the reforming reactor is a riser reactor or a downflow fluidized bed reactor, the primary regeneration reactor and the secondary regeneration reactor are both riser fluidized bed reactors, and the pyrolysis coke combustion reactor is a fluidized bed reactor with water-cooled walls inside.

[0014] Preferably, it further includes: a first cyclone separator, a second cyclone separator, a third cyclone separator, a fourth cyclone separator, a fifth cyclone separator, a first return valve, a second return valve, and a third return valve; The first cyclone separator is connected between the volatile matter outlet of the pyrolysis reactor and the inlet of the spray tower; The second cyclone separator is connected to the syngas outlet of the reforming reactor; The third cyclone separator is connected to the top outlet of the pyrolysis coke combustion reactor; The fourth cyclone separator is connected to the top discharge port of the primary regeneration reactor; The fifth cyclone separator is connected to the top discharge port of the secondary regeneration reactor; The first return valve is located between the oxygen carrier outlet of the reforming reactor and the oxygen carrier inlet of the first-stage regeneration reactor. The second return valve is located between the oxygen carrier outlet of the primary regeneration reactor and the oxygen carrier inlet of the secondary regeneration reactor. The third return valve is located between the regenerated oxygen carrier outlet of the secondary regeneration reactor and the oxygen carrier inlet of the reforming reactor.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing hydrogen-rich syngas through chemical chain reforming coupled with staged regeneration of pyrolysis gas from biomass pyrolysis volatiles. The method involves separating pyrolysis volatiles into large and small molecules via condensation. The large molecules enter the reforming reaction zone and undergo partial oxidation with the oxygen carrier to generate hydrogen-rich syngas. The small molecules (rich in CO2 and CH4) are fed into the primary regeneration reaction zone along with the flue gas from the combustion of pyrolysis coke. This process utilizes the weak oxidizing properties of CO2 to perform primary oxidation of the reduced oxygen carrier, and the CH4 in the small molecules undergoes dry reforming with CO2, simultaneously eliminating carbon deposits on the oxygen carrier surface while producing syngas. The oxygen carrier after primary regeneration is then completely regenerated with air in the secondary regeneration reaction zone. The oxygen-deficient air is returned to the combustion reaction zone for pyrolysis coke combustion. This method transforms endogenous CO2 from a reforming interfering factor into a regenerable resource, avoiding competition between CO2 and hydrocarbons such as CH4 for active sites on the oxygen carrier, improving the selectivity and yield of hydrogen-rich syngas, and simultaneously achieving resource utilization of CO2 and system thermal self-sufficiency.

[0016] This invention discloses a system for producing hydrogen-rich syngas through the chemical chaining reforming coupling of biomass pyrolysis volatile matter and staged regeneration of pyrolysis gas. A complete closed-loop cycle is formed through specific connections between a pyrolysis reactor, a spray tower, a reforming reactor, a pyrolysis coke combustion reactor, a primary regeneration reactor, and a secondary regeneration reactor. The volatile matter produced in the pyrolysis reactor is separated into large and small molecules by the spray tower. Large molecules enter the reforming reactor to produce hydrogen-rich syngas, while small molecules, along with the flue gas from the pyrolysis coke combustion reactor, enter the primary regeneration reactor for initial oxygen carrier regeneration and coupled dry reforming. The primary regenerated oxygen carrier is then completely regenerated by air in the secondary regeneration reactor and recycled back to the reforming reactor. The oxygen-deficient air is returned to the pyrolysis coke combustion reactor. This system structurally ensures the transformation of endogenous CO2 from a reforming interference to a regenerable resource, avoids competition between CO2 and hydrocarbons such as CH4 for active sites on the oxygen carrier, and achieves thermal self-sustaining operation without external heating. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a method for preparing hydrogen-rich syngas by coupling pyrolysis gas with chemical chain reforming of biomass volatile matter and staged regeneration of pyrolysis gas according to the present invention; Figure 2 This is a schematic diagram of a biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas to prepare hydrogen-rich syngas, as proposed in this invention. Figure 3 This invention relates to the regeneration characteristics of an oxygen carrier in the preparation of hydrogen-rich syngas through a process of chemical chain reforming coupled with staged regeneration of pyrolysis volatiles from biomass pyrolysis. Figure 4 This paper compares experimental and simulation results of a biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas to prepare hydrogen-rich syngas, as proposed in this invention.

[0018] Wherein: 1-Pyrolysis reactor; 101-Biomass screw feeder; 102-First cyclone separator; 103-Gas heat exchanger; 104-Booster blower; 105-Spray tower; 106-Heat exchanger; 2-Reforming reactor; 201-Second cyclone separator; 202-First return valve; 203-Steam generator; 3-Pyrolysis coke combustion reactor; 301-Third cyclone separator; 302-Ash hopper; 4-First-stage regeneration reactor; 401-Fourth cyclone separator; 402-Second return valve; 5-Second-stage regeneration reactor; 501-Fifth cyclone separator; 502-Third return valve; Dashed arrows represent the direction of gas flow. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0020] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0021] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0022] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0023] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0024] In this invention, unless otherwise specified, the numerical range "a~b" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation for these numerical combinations.

[0025] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0026] The term “and / or” as used in this invention refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0027] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0028] Pyrolysis reactor 1 (PR); Reforming reactor 2 (FR); Combustion reactor 3 (CR); First regeneration reactor 4 (FRR); Second regeneration reactor 5 (SRR).

[0029] The purpose of this invention is to provide a method and system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatiles with chemical chain reforming and staged regeneration of pyrolysis gas. This method separates biomass pyrolysis and chemical chain reforming, reducing the competitive occupation of active sites and the selective instability of syngas caused by strong reaction coupling. Simultaneously, it achieves the synergistic conversion of CO2 and methane in the pyrolysis volatiles, efficiently reducing carbon emissions. A spray device is used to separate and directionally convert large and small molecules, thereby achieving deep coupling between endogenous CO2-assisted oxygen carrier regeneration and methane dry reforming. Specifically, the biomass pyrolysis volatiles are separated into large molecules rich in oxygen-containing compounds and small molecules rich in CO2 and CH4. The large molecules (including phenols, ketones, aldehydes, etc.) enter the reforming reactor 2, where selective partial oxidation and steam reforming occur under the action of lattice oxygen in the oxygen carrier, converting them into hydrogen-rich syngas. The reduced oxygen carrier after the reaction then enters the primary regeneration reactor 4. Small molecules rich in CO2, along with CH4, H2, and CO, are fed into the primary regeneration reactor 4. The weak oxidizing properties of CO2 are used to perform primary regeneration of the reduced oxygen carrier, restoring its lattice oxygen activity. Simultaneously, CO2 and CH4 from the small molecules undergo an in-situ dry reforming reaction on the surface of the reduced oxygen carrier (CH4 + CO2 → 2H2 + 2CO), further co-producing syngas. This process forms a tight coupling: macromolecular reforming consumes lattice oxygen and reduces the oxygen carrier, while CO2 from the small molecules replenishes lattice oxygen through primary regeneration. The dry reforming reaction simultaneously converts CO2 and CH4, achieving the integration of endogenous CO2 utilization and syngas production enhancement. This coupling strategy not only overcomes the competitive inhibition of active sites by endogenous CO2 but also converts it into beneficial reactants, significantly improving volatile matter conversion efficiency and achieving CO2 emission reduction and syngas co-production.

[0030] This invention discloses a method for preparing hydrogen-rich syngas through biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas, comprising the following steps: S1: Biomass rapidly pyrolyzes under the action of an inert fluidizing medium and a heat transfer medium, producing pyrolytic volatile macromolecules, volatile small molecules, and pyrolytic coke. The volatiles and pyrolytic coke are separated by the first cyclone separator 102. S2: Spray tower 105 separates the pyrolysis volatiles in S1 to obtain small volatile molecules and large volatile molecules; S3: The volatile macromolecules in S2 are fed together with the superheated steam generated by the steam generator 203 and obtained through heat exchange into the reforming reactor 2, where they undergo a partial oxidation reaction with the oxygen carrier to produce hydrogen-rich syngas and reduced oxygen carrier. S4: The pyrolytic coke in S1 is burned with air in the pyrolytic coke combustion reactor 3 to obtain combustion flue gas and ash. The combustion flue gas exchanges heat with the steam generated by the steam generator 203 to obtain superheated steam, which is used for the partial oxidation reaction in S3. S5: The volatile small molecules in S2 and the flue gas after combustion in S4 are fed into the primary regeneration reactor 4 to obtain primary regenerated oxygen carrier and high-temperature carbon-rich gas. S6: The primary regenerated oxygen carrier in S5 enters the secondary regeneration reactor 5 and reacts with air or oxygen to achieve complete regeneration, resulting in a fully regenerated oxygen carrier and oxygen-deficient air. The oxygen-deficient air is used in the pyrolysis combustion process in S4. S7: The oxidized oxygen carrier in S6 is recycled into reformer 2 to undergo partial oxidation.

[0031] In step S4, the high-temperature flue gas and the inert fluidizing medium in S1 exchange heat through the gas heat exchanger 103 and then become the pyrolysis inert medium. The temperature of the pyrolysis inert medium is 400-600 ℃.

[0032] The pyrolysis reactor 1 is a fluidized bed reactor with a reaction temperature of 400-600 ℃. The biomass raw material is agricultural and forestry waste, such as wheat straw and sawdust. The biomass particle size is 0.3-1.5 mm. The heat transfer medium is inert solid particles such as sand or silica. The spraying medium of the spray tower 105 is low-temperature liquid water with a temperature of 20-40 ℃.

[0033] Reforming reactor 2 is a riser reactor with a reaction temperature of 700-900 ℃. The oxygen carrier is a modified natural ore or metal oxide with a particle size of 0.1-0.45 mm. The superheated steam temperature is 150-300 ℃. The metal oxide oxygen carrier may include Fe2O3, NiFe2O4, perovskite ABO3 type, and various modified carriers such as SBA-15, Al2O3, and SiO2.

[0034] Both the primary regeneration reactor 4 and the secondary regeneration reactor 5 are riser reactors. The temperature of the primary regeneration reactor 4 is 50-100 ℃ higher than that of the reforming reactor 2, and the temperature of the secondary regeneration reactor 5 is 50-100 ℃ higher than that of the primary regeneration reactor 4.

[0035] The present invention discloses a biomass pyrolysis volatile matter chemical chain reforming coupled with pyrolysis gas staged regeneration process, comprising a pyrolysis reactor 1, a reforming reactor 2, a primary regeneration reactor 4, a secondary regeneration reactor 5, and a pyrolysis coke combustion reactor 3.

[0036] The pyrolysis reactor 1 is equipped with a biomass feed inlet, an air inlet, a heat transfer medium inlet, a pyrolysis coke outlet, a heat transfer medium outlet, and a volatile matter outlet.

[0037] The reforming reactor 2 is equipped with an oxygen carrier inlet, a steam inlet, a volatile matter inlet, a syngas outlet, and an oxygen carrier outlet.

[0038] The primary regeneration reactor 4 is equipped with a volatile small molecule inlet, an oxygen carrier inlet, a combustion flue gas inlet, an oxygen carrier outlet, and a gas outlet.

[0039] The secondary regeneration reactor 5 is equipped with an oxygen carrier inlet, an air inlet, an oxygen carrier outlet, and an oxygen-deficient air outlet.

[0040] The pyrolysis coke combustion reactor 3 is equipped with a pyrolysis coke inlet, a heat transfer medium inlet, an oxygen-deficient air inlet, an air inlet, a water inlet, a combustion flue gas outlet, a superheated steam outlet, and an ash outlet.

[0041] The outlet of small volatile molecules in pyrolysis reactor 1 is connected to the inlet of small volatile molecules in primary regeneration reactor 4, the outlet of large volatile molecules is connected to the inlet of volatiles in reforming reactor 2, and the outlet of pyrolysis coke is connected to the inlet of pyrolysis coke combustion reactor 3.

[0042] The oxygen carrier outlet of reformer 2 is connected to the oxygen carrier inlet of primary regeneration reactor 4.

[0043] The oxygen carrier outlet of the primary regeneration reactor 4 is connected to the oxygen carrier inlet of the secondary regeneration reactor 5.

[0044] The oxygen carrier outlet of the secondary regeneration reactor 5 is connected to the oxygen carrier inlet of the reforming reactor 2, and the oxygen-deficient air outlet is connected to the oxygen-deficient air inlet of the pyrolysis coke combustion reactor 3.

[0045] The combustion gas outlet of the pyrolysis coke combustion reactor 3 is connected to the combustion gas inlet of the primary regeneration reactor 4, and the superheated steam outlet is connected to the steam inlet of the reforming reactor 2.

[0046] The outlet of the heat transfer medium of the pyrolysis coke combustion reactor 3 is connected to the inlet of the heat transfer medium of the pyrolysis reactor 1.

[0047] This invention discloses a system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, such as... Figure 2 As shown, it includes: a pyrolysis reactor 1, a biomass screw feeder 101, a first cyclone separator 102, a gas heat exchanger 103, a booster fan 104, a spray tower 105, a heat exchanger 106, a downflow fluidized bed reforming reactor 2, a second cyclone separator 201, a first return valve 202, a steam generator 203, a pyrolysis coke combustion reactor 3, a third cyclone separator 301, an ash hopper 302, a primary regeneration reactor 4, a fourth cyclone separator 401, a second return valve 402, a secondary regeneration reactor 5, a fifth cyclone separator 501, a third return valve 502, and several valves and pipelines.

[0048] Among them, the biomass screw feeder 101 is connected to the feed inlet of the fluidized bed reactor 1, the outlet of the gas heat exchanger 103 is connected to the air inlet of the booster blower 104, the air outlet of the booster blower 104 is connected to the air inlet of the pyrolysis reactor 1, the top gas outlet of the first cyclone separator 102 is connected to the inlet of the spray tower 105, the bottom solid outlet is connected to the inlet of the pyrolysis coke combustion reactor 3, the gas outlet of the spray tower 105 is connected to the volatile small molecule inlet of the first-stage regeneration reactor 4, and the bottom outlet is connected to the volatile inlet of the reforming reactor 2.

[0049] The top discharge port of the reforming reactor 2 is connected to the inlet of the second cyclone separator 201. The top outlet of the second cyclone separator 201 discharges hydrogen-rich synthesis gas, and the bottom discharge port is connected to the oxygen carrier inlet of the first return valve 202. The outlet of the first return valve 202 is connected to the oxygen carrier inlet of the first-stage regeneration reactor 4. The outlet of the steam generator 203 is connected to the water inlet of the pyrolysis coke combustion reactor 3. The water is preheated into superheated steam by the pyrolysis coke combustion reactor 3, and the superheated steam outlet of the pyrolysis coke combustion reactor 3 is connected to the steam inlet of the reforming reactor 2.

[0050] The air booster fan 104 is connected to the gas inlet of the pyrolysis coke combustion reactor 3. The top of the pyrolysis coke combustion reactor 3 is connected to the inlet of the third cyclone separator 301. The top gas outlet of the third cyclone separator 301 is connected to the gas inlet of the first-stage regeneration reactor 4. The heat transfer medium outlet of the third cyclone separator 301 is connected to the heat transfer medium inlet of the fluidized bed reactor 1. The bottom solid discharge port of the third cyclone separator 301 is connected to the ash hopper 302.

[0051] The top discharge port of the primary regeneration reactor 4 is connected to the inlet of the fourth cyclone separator 401. The top outlet of the fourth cyclone separator 401 is connected to the top inlet of the gas heat exchanger 103. The bottom discharge port of the fourth cyclone separator 401 is connected to the oxygen carrier inlet of the second return valve 402. The oxygen carrier outlet of the second return valve 402 is connected to the oxygen carrier inlet of the secondary regeneration reactor 5.

[0052] The top discharge port of the secondary regeneration reactor 5 is connected to the inlet of the fifth cyclone separator 501. The top outlet of the fifth cyclone separator 501 is connected to the gas inlet of the pyrolysis coke combustion reactor 3. The bottom discharge port of the fifth cyclone separator 501 is connected to the oxygen carrier inlet of the third return valve 502. The oxygen carrier outlet of the third return valve 502 is connected to the oxygen carrier inlet of the reforming reactor 2.

[0053] After the reaction, the oxygen carrier enters the first return valve 202 through the bottom discharge port of the second cyclone separator 201, and enters the first-stage regeneration reactor 4 under the action of inert carrier gas.

[0054] The oxidation medium in the primary regeneration reactor 4 is the pyrolysis volatile small molecules and the combustion flue gas from the pyrolysis coke combustion reactor 3. The gas generated after regeneration in the primary regeneration reactor 4 enters the gas heat exchanger 103 through the top gas outlet of the fourth cyclone separator 401 and exchanges heat with the inert carrier gas before entering the carbon capture device. The oxidation medium in the secondary regeneration reactor 5 is air. The regenerated oxygen carrier is circulated into the reforming reactor 2 through the bottom discharge port of the fifth cyclone separator 501. The regenerated oxygen-deficient air enters the pyrolysis coke combustion reactor 3 through the top gas outlet of the fifth cyclone separator 501.

[0055] The flue gas outlet of gas heat exchanger 103 is rich in carbon gas, which can be connected to a carbon capture device to achieve zero-carbon operation of the entire device.

[0056] This invention separates macromolecules and small molecules from the volatiles of biomass pyrolysis using a spray tower 105 for condensation. It then utilizes the endogenous carbon dioxide generated from biomass pyrolysis to regenerate a reduced oxygen carrier, converting uncontrollable biological oxygen into controllable lattice oxygen within the oxygen carrier. This enables controllable syngas production during the reforming stage. The separated small-molecule volatiles (containing methane and carbon dioxide) are fed into a primary regeneration reactor 4, where the catalytic effect of the reduced oxygen carrier facilitates the conversion of carbon dioxide and methane into syngas. Within the conventional two-stage regeneration framework, this invention innovatively utilizes the endogenous CO2 and CH4 obtained from the separation of biomass pyrolysis volatiles to achieve co-production of oxygen carrier regeneration and syngas.

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some, not all, of the embodiments of the present invention. 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. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. 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.

[0058] Example 1 A method for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, such as... Figure 1 As shown, it includes the following steps: S11. The pretreated (dried, crushed, etc.) biomass raw material is added to the pyrolysis reactor 1 through the biomass screw feeder 101. After pyrolysis, the biomass produces volatiles and pyrolysis coke, which are separated by the first cyclone separator 102. An inert bed material is used as the heat transfer medium, and the inert fluidizing medium is an inert carrier gas.

[0059] Preferably, the pyrolysis reactor 1 is a fluidized bed reactor. To improve pyrolysis efficiency, the inert carrier gas mentioned in S11 is the inert gas after heat exchange with the flue gas generated in the primary regeneration reactor 4 in the gas heat exchanger 103, and the temperature of the inert carrier gas is about 300 ℃. The inert heat transfer medium is silicon dioxide, which is introduced into the pyrolysis reactor 1 by the inert carrier gas after being supplemented with heat by the pyrolysis coke combustion reactor 3, and the temperature is about 400-600 ℃.

[0060] S12. As described in S11, the solids separated by the first cyclone separator 102 enter the pyrolysis coke combustion reactor 3, which contains pyrolysis coke and an inert heat transfer medium. The pyrolysis coke reacts with the air entering from the bottom of the pyrolysis coke combustion reactor 3 to produce combustion flue gas. The combustion flue gas and silica are separated in the third cyclone separator 301. In this process, the silica replenishes heat and is returned to the pyrolysis reactor 1 as a heat transfer medium, while the combustion flue gas enters the primary regeneration reactor 4 as a fluidizing medium.

[0061] Preferably, the pyrolysis reactor 1 is equipped with a water-cooled wall for secondary heating of steam to generate superheated steam. During this process, the superheated steam is used for partial oxidation of the steam in the reforming reactor 2, and the superheated steam temperature is approximately 200-300 °C. The air used in the pyrolysis coke combustion reactor 3 is the oxygen-deficient air from the gas outlet of the secondary regeneration reactor 5.

[0062] S13. As described in S11, the volatile components are divided into small volatile molecules and large volatile molecules. After being separated by spray tower 105, the small volatile molecules rich in carbon dioxide enter the primary regeneration reactor 4. The condensed large volatile molecules enter the oil storage tank after oil-water separation. Further, under the action of superheated steam as described in S12, both enter the reforming reactor 2.

[0063] S14. The carbon dioxide-rich volatile molecules, as described in S13, together with the combustion flue gas described in S12, enter the primary regeneration reactor 4 to undergo primary regeneration of the used oxygen carrier, obtaining the primary regenerated oxygen carrier. The used oxygen carrier is carried by the combustion flue gas from the fourth cyclone separator 401 into the secondary regeneration reactor 5. Simultaneously, CO2 in the volatiles undergoes a dry reforming process with methane and carbon deposits on the surface of the oxygen carrier, further utilizing the carbon dioxide.

[0064] Preferably, the oxygen carrier after use is the oxygen carrier after reaction in the reforming reactor 2, whose lattice oxygen has been removed and whose surface contains a certain degree of carbon deposits, and whose temperature is about 700-800 ℃.

[0065] S15. As described in S13, the volatile macromolecules undergo a partial steam oxidation reaction with the regenerated oxygen carrier to produce hydrogen-rich syngas and reduced oxygen carrier, which are then separated by the third cyclone separator 301.

[0066] Preferably, the regenerated oxygen carrier is the oxygen carrier that has been fully regenerated in the secondary regeneration reactor 5 and then carried back to the reforming reactor 2 by the fluidizing medium through a sealing ring, with a temperature of approximately 750-850 °C. The reduced oxygen carrier is an oxygen carrier with lattice oxygen removed. The fluidizing medium is an inert carrier gas.

[0067] S16. As described in S14, the oxygen carrier of the primary regeneration enters the secondary regeneration reactor 5 and undergoes a complete oxygen carrier regeneration reaction with air. After the reaction, a fully regenerated oxygen carrier and oxygen-deficient air are obtained, and the two pass through the fifth cyclone separator 501.

[0068] Preferably, the generated oxygen-deficient air enters the pyrolysis coke combustion reactor 3 described in S12 and undergoes a combustion reaction with the pyrolysis coke.

[0069] Example 2 A system for producing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, such as... Figure 2 As shown, it includes: 1. Pyrolysis The crushed and dried biomass is conveyed to the fluidized bed pyrolysis reactor 1 by a biomass screw feeder 101, with the biomass fed from the side. The bottom inert gas serves as the fluidizing carrier gas, having already exchanged heat with the flue gas from the outlet of the primary regeneration reactor 4 in the gas heat exchanger 103 before entering the pyrolysis reactor 1. The heat transfer medium inside the reactor is sand or silica, which has been reheated in the pyrolysis coke combustion reactor 3 before entering the pyrolysis reactor 1. The possible reactions within the pyrolysis reactor 1 are shown in R1, producing small volatile molecules (CO, CO2, CH4, NH3), large volatile molecules (ketones, aldehydes, phenolic products), and pyrolysis coke. The outlet of the pyrolysis reactor 1 is a first cyclone separator 102, which separates the gaseous volatiles, solid pyrolysis coke, and the heat transfer medium. Further, the volatiles are separated into small and large molecules by a spray tower 105.

[0070]

[0071] 2. Combustion Solid pyrolysis coke and the heat transfer medium enter the pyrolysis coke combustion reactor 3 and undergo a combustion reaction with the oxygen-deficient air in the secondary regeneration reactor 5, as shown in the reaction equation R2. The pyrolysis coke combustion reactor 3 is a fluidized bed reactor, with solid pyrolysis coke and the heat transfer medium fed from the top and oxygen-deficient air fed from the bottom. The reactor is equipped with water-cooled walls for heating steam. After the reaction, combustion flue gas and heated solid heat transfer medium are obtained. These two are separated by a third cyclone separator 301. The flue gas enters the primary regeneration reactor 4, while the heat transfer medium is returned to the pyrolysis reactor 1. In addition, the steam is heated to superheated steam at a temperature of 180-300 ℃ and a pressure of 0.15 MPa.

[0072]

[0073] 3. Restructuring The volatile macromolecules (ketones, aldehydes, and phenolic products) separated by spray tower 105 are carried into reformer 2 by superheated steam, where they undergo a reforming reaction with the oxygen carrier, as shown in reactions R3-R5. Reformer 2 is a fluidized bed reactor; the volatiles are fed from the bottom, and the oxygen carrier is the regenerated oxygen carrier returned from secondary regeneration reactor 5 to reformer 2, fed from the side. After the reaction, hydrogen-rich syngas and the used oxygen carrier are obtained. Further, the hydrogen-rich syngas undergoes acid gas removal and water-gas shift reaction to obtain green hydrogen.

[0074]

[0075] 4. Primary Regeneration The volatile small molecules (CO, CO2, CH4, NH3) separated by spray tower 105 and the combustion flue gas from the pyrolysis coke combustion reactor 3 enter the primary regeneration reactor 4 together with the used oxygen carrier to undergo an oxidation reaction, as shown in R6-R8. This achieves the coupling of in-situ CO2 conversion and oxygen carrier regeneration. The gas obtained from the reaction and the initially regenerated oxygen carrier are separated by the fourth cyclone separator 401. The gas enters the gas heat exchanger 103 to exchange heat with the inert carrier gas in the pyrolysis reactor 1, and the initially regenerated oxygen carrier enters the secondary regeneration reactor 5. The primary regeneration reactor 4 is a fluidized bed reactor, with gas fed from the bottom and the used oxygen carrier fed from the side.

[0076]

[0077] 5. Secondary Regeneration The initially regenerated oxygen carrier enters the secondary regeneration reactor 5, where it undergoes a complete regeneration reaction with air, as shown in R9. The resulting oxygen-deficient air and fully regenerated oxygen carrier pass through the fifth cyclone separator 501. The oxygen-deficient air enters the pyrolysis coke combustion reactor 3, while the fully regenerated oxygen carrier enters the reforming reactor 2. The secondary regeneration reactor 5 is a fluidized bed reactor, with air fed from the bottom and the initially regenerated oxygen carrier fed from the side.

[0078]

[0079] Example 3 Natural mineral metal oxides are used as oxygen carriers, with Fe2O3 as the main component and a particle size of approximately 0.14-0.18 mm. Wheat straw is used as the biomass raw material.

[0080] Wheat straw, as a biomass raw material, is dried and pre-treated by crushing before being conveyed to a fluidized bed pyrolysis reactor 1 by a biomass screw feeder 101. Under the action of a carrier gas and a heat transfer medium, pyrolysis produces pyrolysis volatiles and pyrolysis coke. The temperature inside the pyrolysis reactor 1 is approximately 400-600°C. The fluidizing medium is inert nitrogen gas at a temperature of 200-300°C and a pressure of 0.15 MPa. After separation by a first cyclone separator 102, the pyrolysis coke enters the pyrolysis coke combustion reactor 3 from the bottom to undergo combustion, producing flue gas while simultaneously heating the heat transfer medium. The volatiles are separated by a spray tower 105 to obtain large and small volatile molecules. The small volatile molecules, along with the flue gas from the pyrolysis coke combustion reactor 3, enter the primary regeneration reactor 4 to react with the used oxygen carrier, obtaining a primary regenerated oxygen carrier. The CO2 content in the small volatile molecules is approximately 30%, and the CO2 content in the flue gas produced by the pyrolysis coke combustion reactor 3 is approximately 50%. After separation by the fourth cyclone separator 401, the primary regeneration reactor enters the secondary regeneration reactor 5, where it undergoes a complete regeneration reaction with air, yielding regenerated oxygen carrier and oxygen-deficient air. Both are then separated by the fifth cyclone separator 501. The separated oxygen carrier is carried by inert gas into the reforming reactor 2, while the oxygen-deficient air enters the pyrolysis coke combustion reactor 3 to undergo a combustion reaction with the pyrolysis coke. After heat exchange in the pyrolysis coke combustion reactor 3, superheated steam at approximately 200-300 °C carries the large volatile molecules into the reforming reactor 2 in a bubbling manner. There, they undergo a partial oxidation reaction with the fully regenerated oxygen carrier returned to the reforming reactor 2, producing hydrogen-rich syngas and used oxygen carrier. The temperature inside the reforming reactor 2 is approximately 750-850 °C. Further, the hydrogen-rich syngas undergoes acid gas removal and water-gas shift reaction to obtain green hydrogen.

[0081] like Figure 3As shown, the primary regeneration process of the oxygen carrier by volatile small molecules was simulated. It was assumed that the oxygen carrier after use existed in the form of FeO, and the CO2 content in the volatile small molecules was 30 vol%. The reaction equation is shown in R10. The oxygen carrier after the reaction contained 18.17 wt% Fe3O4, and the lattice oxygen recovery rate was approximately 8.8%. Calculated according to formula (1), where The actual recovered lattice oxygen (0.9 wt% by mass fraction of Fe2O3). The theoretically recoverable lattice oxygen (10 wt% by mass fraction of Fe2O3) was achieved. In-situ CO2 conversion and oxygen carrier regeneration were coupled.

[0082]

[0083] Example 4 A hydrogen production process involving the chemical chain reforming of biomass pyrolysis volatiles coupled with staged regeneration of pyrolysis gas, wherein the oxygen carrier is the core of the entire reaction system and needs to possess the following characteristics: 1) Oxygen-carrying and moderate oxygen release capacity: The oxygen carrier, as a reactant, needs to participate in the chemical reaction, providing controllable lattice oxygen. The rate at which the oxygen carrier releases lattice oxygen needs to match the rate of dissociation of volatile macromolecules to achieve partial oxidation and produce hydrogen-rich syngas. The active metal in the multifunctional oxygen carrier acts as a catalyst, catalyzing the breaking of C-C and CH bonds in the volatiles. 2) Excellent cycle stability: The oxygen carrier is recycled between reforming reactor 2, primary regeneration reactor 4, and secondary regeneration reactor 5, requiring good wear resistance. 3) Good heat transfer performance: As a heat transfer medium, the oxygen carrier's thermal effect is used to transfer heat from the secondary regeneration reactor to reforming reactor 2.

[0084] Based on this, NiFe2O4 encapsulated with molecular sieves was used as a multifunctional oxygen carrier, with NiFe2O4 as the active component and a particle size of approximately 0.15 mm. Mature reeds were used as the biomass feedstock.

[0085] Reeds, as biomass raw material, are dried and pre-treated by crushing before being conveyed to fluidized bed pyrolysis reactor 1 by a biomass screw feeder 101. Under the action of carrier gas and heat transfer medium, pyrolysis produces pyrolysis volatiles and pyrolysis coke. The temperature inside pyrolysis reactor 1 is approximately 500-600 °C. The fluidizing medium is inert nitrogen gas at 200-300 °C. After separation by the first cyclone separator 102, the pyrolysis coke enters the pyrolysis coke combustion reactor 3 from the bottom to undergo combustion, producing flue gas while simultaneously heating the heat transfer medium. The volatiles are separated by a spray tower 105 to obtain large and small volatile molecules. The small volatile molecules, along with the flue gas from the pyrolysis coke combustion reactor 3, enter the primary regeneration reactor 4 to react with the used oxygen carrier, obtaining the primary regenerated oxygen carrier. The CO2 content in the small volatile molecules is approximately 20%, and the CO2 content in the flue gas from the pyrolysis coke combustion reactor 3 is approximately 40%. The oxygen carrier from the primary regeneration process is separated by the fourth cyclone separator 401 and then enters the secondary regeneration reactor 5, where it undergoes a complete regeneration reaction with air to obtain regenerated oxygen carrier and oxygen-deficient air. Both are then passed through the fifth cyclone separator 501. The separated oxygen carrier is carried by inert carrier gas into the reforming reactor 2, while the oxygen-deficient air enters the pyrolysis coke combustion reactor 3 to undergo a combustion reaction with the pyrolysis coke. After heat exchange in the pyrolysis coke combustion reactor 3, superheated steam at approximately 180 °C carries the volatile macromolecules into the reforming reactor 2 in a bubbling manner. There, it undergoes a partial oxidation reaction with the fully regenerated oxygen carrier returned to the reforming reactor 2 to produce hydrogen-rich syngas and the used oxygen carrier. The temperature inside the reforming reactor 2 is approximately 750-850 °C. Further, the hydrogen-rich syngas undergoes acid gas removal and water-gas shift reaction to obtain green hydrogen.

[0086] Example 5 Microalgae (particle size 0.3-1.5 mm, moisture content 5% after pretreatment) are used as pyrolysis feedstock, perovskite is used as oxygen carrier, small volatile molecules generated by pyrolysis are used as primary regeneration feedstock, and large volatile molecules generated by pyrolysis are used as reforming feedstock.

[0087] Microalgae, as a biomass raw material, are dried and pre-treated by crushing before being transported to a fluidized bed pyrolysis reactor 1 via a biomass screw feeder 101. Under the action of a carrier gas and a heat transfer medium, pyrolysis produces pyrolysis volatiles and pyrolysis coke. The temperature inside the pyrolysis reactor 1 is approximately 500-600 °C. The fluidizing medium is inert nitrogen gas at 200-300 °C. After separation by the first cyclone separator 102, the pyrolysis coke enters the pyrolysis coke combustion reactor 3 from the bottom to undergo combustion, producing flue gas and simultaneously heating the heat transfer medium. The volatiles are separated by a spray tower 105 to obtain large and small volatile molecules. The small volatile molecules (NH3, HCN, and CO2, etc.) and the flue gas from the pyrolysis coke combustion reactor 3 enter the primary regeneration reactor 4 to react with the used oxygen carrier (CO2 + La2O3 → La2O2CO3) to obtain a primary regenerated oxygen carrier, while simultaneously suppressing NO. x The primary regeneration reactor, after separation by the fourth cyclone separator 401, enters the secondary regeneration reactor 5, where it undergoes a complete regeneration reaction with air, yielding regenerated oxygen carrier and oxygen-deficient air. Both are then separated by the fifth cyclone separator 501. The separated oxygen carrier is carried by inert carrier gas into the reforming reactor 2, while the oxygen-deficient air enters the pyrolysis coke combustion reactor 3 to undergo a combustion reaction with the pyrolysis coke. After heat exchange in the pyrolysis coke combustion reactor 3, superheated steam at approximately 200-300 °C carries volatile macromolecules into the reforming reactor 2 in a bubbling manner. There, it undergoes a partial oxidation reaction with the fully regenerated oxygen carrier returned to the reforming reactor 2, producing hydrogen-rich syngas and used oxygen carrier. Simultaneously, a catalytic denitrification reaction (NH3→N2+3H2) occurs. The temperature inside the reforming reactor 2 is approximately 750-850 °C. Further, the hydrogen-rich syngas undergoes acid gas removal and water-gas shift reaction to obtain green hydrogen.

[0088] Example 6 The volatiles from biomass pyrolysis are condensed and separated to obtain small-molecule gaseous components rich in endogenous CO2, CH4, H2, and CO, which are then fed into a dry reforming reactor 2 loaded with NiFe2O4@SBA-15 oxygen carrier. This is compared with a method and system for preparing hydrogen-rich syngas through chemical looping reforming of carbon-based solid fuels proposed by Wu Zhiqiang et al. (202111452462.3).

[0089] The experimental conditions are set as follows: The chemical reforming experiment of volatile matter from wheat straw pyrolysis was conducted in a fixed-bed reactor. It mainly includes a gas distribution system, a reactor system, a product condensation system, a product collection system, and a product detection system. The gas distribution system includes gas cylinders, a mass flow meter, and a peristaltic pump. The reactor system consists of a pyrolysis reactor 1, a reforming reactor 2, a primary regeneration reactor 4, and a secondary regeneration reactor 5, each consisting of a heating furnace and a quartz tube reactor. The upper reactor is used for the pyrolysis of wheat straw, and the lower reactor is used for the chemical reforming of volatile matter from pyrolysis, with regeneration achieved through gas switching. The product condensation system consists of three gas washing bottles connected in series and filled with acetone. The product collection and detection system consists of an aluminum foil gas collection bag, a gas chromatograph (model: FULI INSTRUMENTS GC9790Plus) with a flame ionization detector (FID) and a thermal conductivity detector (TCD), a Karl Fischer moisture analyzer, and a gas chromatography-mass spectrometer (model: GCMS-QP2020NX). Before the reaction begins, a gas flow rate of 200 mL / min is first used. -1 The argon purging system was purged for 30 minutes, then at 10 °C·min. -1 The temperature was increased to the target temperature of 750℃ at a controlled heating rate. Subsequently, small volatile molecules (gas composition: 25 vol% CH4, 12.5 vol% CO2, 8.5 vol% CO, 4 vol% H2, and 50 vol% Ar) were introduced, using 1 g of oxygen carrier at a total flow rate of 200 mL / min. -1 After the reaction was complete, 200 mL·min⁻¹ was used again. -1 The system was purged with argon gas for 30 minutes. After purging, 200 mL of argon gas was introduced. -1 The air was used to regenerate the oxygen carrier. The resulting oxygen carrier was then used in the subsequent chemical chain reforming process of volatile macromolecules. The separated volatile macromolecules were uniformly injected into the reforming reactor over 30 minutes for the chemical chain reforming reaction. In the comparative experiment, there was no spray tower or primary regeneration reactor 4. Before the reaction started, air was first used at a flow rate of 200 mL / min. -1 The argon purging system was purged for 30 minutes, then at 10 °C·min. -1 The temperature was increased to the target temperature of 750℃ at a heating rate of [missing information]. Then, 0.5 g of wheat straw was added to the pyrolysis reactor, and the volatile matter produced was [missing information] at a rate of 200 mL / min. -1 Argon gas was directly introduced into the reforming reactor to react with 1 g of oxygen carrier, and the gaseous products were collected. After the reaction was completed, the product was again distilled at 200 mL / min. -1 The system was purged with argon gas for 30 minutes. After purging, 200 mL of argon gas was introduced. -1Air was used to regenerate the oxygen carrier. Under comparative conditions with high volatile content, the coexisting H2 and CO compete with CH4 for active sites on the oxygen carrier surface and inhibit the effective activation of endogenous CO2, resulting in a significant inhibition of the dry reforming reaction and a low syngas yield. Experimental results showed that the H2 yield, CO yield, and total syngas yield were 45.68 g·kg⁻¹. -1 Biomass, 346.22 g·kg -1 Biomass and 391.90 g·kg -1 Biomass, endogenous CO2 was not fully converted.

[0090] Under the same operating conditions, the experimental results showed that the yields of H2, CO, and total syngas were 40.05 g·kg⁻¹. -1 Biomass, 451.36 g·kg -1 Biomass and 495.41 g·kg -1 Biomass. CO yield increased by approximately 30.4%, and total syngas yield increased by approximately 26.4% (as verified by Aspen Plus simulations, the simulated values ​​for H2 yield, CO yield, and syngas yield for this process are 48.54 g·kg⁻¹). -1 472.90 g·kg -1 and 521.44 g·kg -1 Biomass (which matches the simulation well), such as Figure 4 As shown, the resulting syngas is more suitable for downstream processes requiring high CO content (such as Fischer-Tropsch synthesis), while reducing overall process CO2 emissions by 10.5%. This embodiment demonstrates that endogenous CO2-assisted chemical looping dry reforming can overcome the inhibition of reducing atmospheres without introducing fossil carbon sources, significantly improving syngas yield and realizing the resource utilization of CO2.

[0091] In summary, this invention provides a method and system for preparing hydrogen-rich syngas through chemical chain reforming coupled with staged regeneration of pyrolysis gas from biomass pyrolysis volatiles. The method includes the following steps: pyrolysis of biomass is carried out under a carrier using an inert medium as the heating medium to obtain pyrolysis volatiles and pyrolysis coke. The pyrolysis volatiles are separated into large and small molecules via a spray tower 105. In a reforming reactor 2, an oxygen carrier reacts with the large volatile molecules to produce syngas. The pyrolysis coke is combusted in oxygen-deficient air to produce combustion flue gas, which heats the inert medium. The small volatile molecules and combustion flue gas perform primary regeneration of the oxygen carrier, and the resulting gas is used to heat the pyrolysis carrier gas. Secondary regeneration of the oxygen carrier is achieved using air, and the resulting oxygen carrier is recycled back into the reforming reactor 2. This invention realizes the production of syngas and the utilization of CO2, achieving thermal coupling and realizing the efficient conversion of biomass into high-value products. By separating pyrolysis volatiles through spray tower 105, small molecules rich in CO2 are used for primary regeneration of the oxygen carrier and coupled with the dry reforming reaction. This avoids the competitive inhibition of the reforming reaction by endogenous CO2, while simultaneously converting CO2 into syngas, increasing syngas yield and reducing CO2 emissions. Through two-stage regeneration and system thermal coupling, mild regeneration of the oxygen carrier and system thermal self-sufficiency are achieved, extending the oxygen carrier's lifespan and reducing external energy consumption.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing hydrogen-rich syngas through staged regeneration of biomass pyrolysis volatile matter via chemical chain reforming coupled with pyrolysis gas, characterized in that, Includes the following steps: S1. Biomass undergoes pyrolysis under the action of an inert fluidizing medium and a heat transfer medium, producing pyrolysis volatiles and pyrolysis coke. The separation of pyrolysis volatiles and pyrolysis coke is achieved through gas-solid separation. S2. The pyrolysis volatiles obtained in S1 are condensed and separated into large volatile molecules and small volatile molecules. S3. The volatile macromolecules obtained from S2 are fed into the reforming reaction zone together with superheated steam to undergo a partial oxidation reaction with the oxygen carrier, generating hydrogen-rich syngas and reduced oxygen carrier. S4. The pyrolytic coke obtained in S1 is burned with oxygen-deficient air in the combustion reaction zone to generate combustion flue gas and superheated steam, and the superheated steam is used in S3. S5. The volatile small molecules obtained from S2 and the combustion flue gas obtained from S4 are fed into the primary regeneration reaction zone and come into contact with the reduced oxygen carrier. The weak oxidizing property of CO2 is used to perform primary regeneration of the reduced oxygen carrier. At the same time, the CO2 in the volatile small molecules undergoes a dry reforming reaction with CH4 to generate carbon-rich gas and primary regenerated oxygen carrier. S6. The primary regenerated oxygen carrier obtained in S5 is introduced into the secondary regeneration reaction zone to react with air or oxygen to achieve complete regeneration of the oxygen carrier, resulting in an oxidized oxygen carrier and oxygen-deficient air. The oxygen-deficient air is used in S4. S7. The oxidized oxygen carrier obtained in S6 is recycled back to S3.

2. The method for preparing hydrogen-rich syngas by biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas according to claim 1, characterized in that, In S1, the pyrolysis reaction temperature is 400-600℃; the biomass is wheat straw, reeds, microalgae, corn straw, rice husks or pine sawdust, and the particle size of the biomass is 0.3-1.5 mm; the heat transfer medium is sand or silica. In S2, the condensing medium for the condensation treatment is liquid water at 20-40℃.

3. The method for preparing hydrogen-rich syngas by biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas according to claim 1, characterized in that, In S3, the temperature of the partial oxidation reaction is 700-900℃, the oxygen carrier is Fe2O3 or NiFe2O4, and the particle size of the oxygen carrier is 0.1-0.45 mm; the temperature of the superheated steam is 150-300℃.

4. The method for preparing hydrogen-rich syngas by biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas according to claim 1, characterized in that, In S5, the temperature of the primary regeneration reaction zone is 50-100°C higher than the temperature of the reforming reaction zone in S3. In S6, the temperature of the secondary regeneration reaction zone is 50-100°C higher than the temperature of the primary regeneration reaction zone in S5.

5. The method for preparing hydrogen-rich syngas by biomass pyrolysis volatile matter chemical chain reforming coupled with staged regeneration of pyrolysis gas according to claim 1, characterized in that, In S5, the carbon-rich gas is used to preheat the inert fluidizing medium in S1 after heat exchange.

6. A system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas, characterized in that, The method for preparing hydrogen-rich syngas by chemical chain reforming coupled with pyrolysis gas staged regeneration of biomass pyrolysis volatile matter according to any one of claims 1-5 includes: a pyrolysis reactor (1), a spray tower (105), a reforming reactor (2), a pyrolysis coke combustion reactor (3), a primary regeneration reactor (4), and a secondary regeneration reactor (5). The pyrolysis reactor (1) is provided with a volatile matter outlet and a pyrolysis coke outlet; The inlet of the spray tower (105) is connected to the volatile matter outlet of the pyrolysis reactor (1), and the spray tower (105) is provided with a small volatile molecule gas outlet and a large volatile molecule liquid outlet. The reforming reactor (2) is provided with a volatile matter inlet, a steam inlet, an oxygen carrier inlet, a syngas outlet and an oxygen carrier outlet. The volatile matter inlet of the reforming reactor (2) is connected to the volatile matter macromolecular liquid outlet of the spray tower (105). The pyrolysis coke combustion reactor (3) is provided with a pyrolysis coke inlet, an oxygen-deficient air inlet, a steam inlet, a superheated steam outlet and a combustion flue gas outlet. The pyrolysis coke inlet of the pyrolysis coke combustion reactor (3) is connected to the pyrolysis coke outlet of the pyrolysis reactor (1); the superheated steam outlet of the pyrolysis coke combustion reactor (3) is connected to the steam inlet of the reforming reactor (2). The primary regeneration reactor (4) is provided with a gas inlet, an oxygen carrier inlet and an oxygen carrier outlet. The gas inlet of the primary regeneration reactor (4) is connected to the volatile small molecule gas outlet of the spray tower (105) and the combustion flue gas outlet of the pyrolysis coke combustion reactor (3), respectively. The oxygen carrier inlet of the primary regeneration reactor (4) is connected to the oxygen carrier outlet of the reforming reactor (2). The secondary regeneration reactor (5) is provided with an oxygen carrier inlet, an air inlet, a regenerated oxygen carrier outlet, and an oxygen-deficient air outlet. The oxygen carrier inlet of the secondary regeneration reactor (5) is connected to the oxygen carrier outlet of the primary regeneration reactor (4), the regenerated oxygen carrier outlet of the secondary regeneration reactor (5) is connected to the oxygen carrier inlet of the reforming reactor (2), and the oxygen-deficient air outlet of the secondary regeneration reactor (5) is connected to the oxygen-deficient air inlet of the pyrolysis coke combustion reactor (3).

7. The system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas according to claim 6, characterized in that, The spray tower (105) has a small molecule gas outlet at the top, a large molecule liquid outlet at the bottom, and a spray medium inlet on the side.

8. The system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas according to claim 6, characterized in that, It also includes a gas heat exchanger (103), the inlet of which is connected to the gas outlet of the primary regeneration reactor (4), and the outlet of which is connected to the inert carrier gas inlet of the pyrolysis reactor (1).

9. The system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas according to claim 6, characterized in that, The pyrolysis reactor (1) is a fluidized bed reactor, the reforming reactor (2) is a riser reactor or a downflow fluidized bed reactor, the primary regeneration reactor (4) and the secondary regeneration reactor (5) are both riser fluidized bed reactors, and the pyrolysis coke combustion reactor (3) is a fluidized bed reactor with water-cooled walls inside.

10. The system for preparing hydrogen-rich syngas by coupling biomass pyrolysis volatile matter chain reforming with staged regeneration of pyrolysis gas according to claim 6, characterized in that, Also includes: First cyclone separator (102), second cyclone separator (201), third cyclone separator (301), fourth cyclone separator (401), fifth cyclone separator (501), first return valve (202), second return valve (402) and third return valve (502); The first cyclone separator (102) is connected between the volatile matter outlet of the pyrolysis reactor (1) and the inlet of the spray tower (105); The second cyclone separator (201) is connected to the syngas outlet of the reforming reactor (2); The third cyclone separator (301) is connected to the top outlet of the pyrolysis coke combustion reactor (3); The fourth cyclone separator (401) is connected to the top discharge port of the primary regeneration reactor (4); The fifth cyclone separator (501) is connected to the top discharge port of the secondary regeneration reactor (5); The first return valve (202) is located between the oxygen carrier outlet of the reforming reactor (2) and the oxygen carrier inlet of the primary regeneration reactor (4); The second return valve (402) is located between the oxygen carrier outlet of the primary regeneration reactor (4) and the oxygen carrier inlet of the secondary regeneration reactor (5); The third return valve (502) is located between the regenerated oxygen carrier outlet of the secondary regeneration reactor (5) and the oxygen carrier inlet of the reforming reactor (2).

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