System for synthesizing green methanol through biomass pyrolysis and gasification

Abstract

The invention discloses a system for synthesizing green methanol by pyrolysis and gasification of biomass, and relates to the technical field of comprehensive utilization of biomass energy, the system comprises a pyrolysis and gasification unit, a synthesis gas treatment unit and a methanol synthesis and rectification unit which are communicated in sequence, and a carbon capture and circulation unit and a self-adaptive thermal management network are integrally arranged; a biomass raw material is subjected to pyrolysis and oxygen-enriched gasification to generate crude synthesis gas, and the crude synthesis gas enters a methanol synthesis and rectification unit to prepare a methanol product after being subjected to purification, water-gas shift regulation of a hydrogen-carbon ratio and acid gas removal; carbon dioxide-containing tail gas and unreacted gas generated in the operation process of the system are introduced into the integrated carbon capture and circulation unit for separation treatment, carbon dioxide obtained through separation returns to the pyrolysis gasification unit to serve as a part of a gasification agent, and effective gas obtained through separation is recycled to a synthesis section.

Description

Technical Field

[0001] This invention relates to the field of biomass energy comprehensive utilization technology, and more specifically, to a biomass pyrolysis gasification synthesis green methanol system. Background Technology

[0002] Against the backdrop of "dual carbon" goals and energy structure transformation, the production of liquid fuels and chemicals from renewable resources has become an important development direction in the energy and chemical industry. Methanol, as a basic chemical raw material and clean fuel, has advantages such as convenient storage and transportation and a wide range of applications, and its green production pathways have attracted widespread attention. Among these, the production of green methanol using biomass resources is considered one of the important technological approaches to achieving renewable carbon cycling and reducing dependence on fossil fuels.

[0003] In existing technologies, biomass-to-methanol production typically employs a process route of biomass gasification—syngas purification—methanol synthesis. Biomass undergoes a gasification reaction to generate syngas, primarily composed of carbon monoxide and hydrogen. After treatments such as tar removal, dust removal, water-gas shift reaction, and acid removal, the syngas enters the methanol synthesis unit to be converted into methanol. However, due to the complex composition and high oxygen content of biomass feedstock, and the significant differences in properties between biomass sources, traditional biomass gasification processes for syngas production generally suffer from problems such as large fluctuations in syngas composition and difficulty in stably controlling the hydrogen-to-carbon ratio, thus limiting methanol synthesis efficiency and system stability.

[0004] Furthermore, existing biomass-to-methanol systems still have significant shortcomings in carbon resource utilization. During syngas treatment and methanol synthesis, large amounts of carbon dioxide-containing tail gas or purge gas are typically generated. These gases are mostly treated as emissions or simple combustion, resulting in the limited carbon resources in biomass not being fully converted into the target product. This not only reduces the system's carbon atom utilization rate but also weakens the carbon reduction advantages of the biomass-to-methanol process. Although some technical solutions incorporate carbon dioxide capture devices, the captured carbon dioxide often lacks efficient reuse pathways, making it difficult to form a true carbon cycle.

[0005] From an energy utilization perspective, both biomass gasification and methanol synthesis processes are highly exothermic or endothermic reactions, resulting in a large amount of waste heat resources at various temperature levels within the system. In existing technologies, this heat is often only partially recovered or directly cooled and discharged, lacking systematic thermal management and cascade utilization design for the entire process. This leads to low overall system energy efficiency, strong dependence on external energy sources, and hinders the economic viability and large-scale application of biomass-to-methanol technology.

[0006] Meanwhile, as system complexity increases, traditional unit-based control methods struggle to cope with fluctuations in biomass feedstock, changes in gas composition, and operational instability caused by multi-unit coupling. The lack of a holistic control strategy for the coordinated optimization of carbon flow, energy flow, and material flow easily leads to local optima while overall efficiency declines, affecting the long-term stable operation of the system.

[0007] Therefore, there is an urgent need for a biomass pyrolysis gasification system to synthesize green methanol to solve these problems. Summary of the Invention

[0008] The purpose of this invention is to solve the technical problems mentioned in the background section and to provide a biomass pyrolysis gasification system for synthesizing green methanol.

[0009] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0010] A biomass pyrolysis gasification system for synthesizing green methanol includes a pyrolysis gasification unit, a syngas treatment unit, and a methanol synthesis and distillation unit connected in sequence.

[0011] An integrated carbon capture and recycling unit has its inlet end connected to the tail gas emission end of the syngas treatment unit and / or the purge gas end of the methanol synthesis and distillation unit, and its outlet end connected to the inlet end of the pyrolysis gasification unit. It is used to capture, separate and reuse carbon dioxide and unreacted gases generated during system operation, so that at least part of the carbon dioxide is returned to the pyrolysis gasification unit as part of the gasification agent.

[0012] An adaptive thermal management network is used for heat recovery, cascade utilization, and distribution among the pyrolysis gasification unit, the syngas treatment unit, and the methanol synthesis and distillation unit, including at least: using part of the heat from the high-temperature syngas generated by the pyrolysis gasification unit for the pretreatment and drying of biomass feedstock, and using the heat released from the methanol synthesis reaction in the methanol synthesis and distillation unit to provide thermal energy for the water-gas shift reaction or other heat-using units in the syngas treatment unit.

[0013] As a preferred technical solution of the present invention, the pyrolysis gasification unit includes a moving bed pyrolysis reactor and an oxygen-enriched gasification furnace arranged in series.

[0014] The moving bed pyrolysis reactor is configured to pyrolyze pretreated biomass feedstock under mesotemperature, anoxic or micro-anoxic conditions to generate pyrolysis gas and biochar.

[0015] The oxygen-enriched gasifier is configured to receive the pyrolysis gas and the carbon dioxide recovered from the integrated carbon capture and recycling unit, and to carry out a high-temperature gasification reaction under oxygen-enriched conditions to generate crude syngas mainly composed of hydrogen and carbon monoxide.

[0016] As a preferred technical solution of the present invention, it also includes a biochar treatment and utilization subsystem, the input end of which is connected to the biochar outlet of the moving bed pyrolysis reactor;

[0017] The biochar treatment and utilization subsystem is configured to activate at least a portion of the biochar and use it as an adsorbent for the impurity removal process in the syngas treatment unit, and / or to transport at least a portion of the biochar as solid fuel to a self-heating burner in the pyrolysis gasification unit to provide heat for the pyrolysis process.

[0018] As a preferred technical solution of the present invention, the syngas treatment unit includes a dust removal and tar removal device, a water-gas shift reactor, and an acid gas removal device connected in sequence.

[0019] The water-gas shift reactor is configured to dynamically adjust the hydrogen-to-carbon ratio in the syngas by regulating the water-gas injection rate and reaction conditions, so that the syngas meets the composition requirements of the methanol synthesis reaction.

[0020] As a preferred embodiment of the present invention, some or all of the reaction heat required by the water-gas shift reactor is recovered and provided by the adaptive thermal management network from the exothermic reaction of methanol synthesis in the methanol synthesis and distillation unit.

[0021] As a preferred technical solution of the present invention, the acid gas removal device adopts a physical-chemical composite absorption process based on phase change absorbent, and the high-concentration carbon dioxide gas flow obtained by desorption during its regeneration process is transported to the integrated carbon capture and recycling unit.

[0022] As a preferred technical solution of the present invention, the integrated carbon capture and recycling unit includes a membrane separation and cryogenic distillation coupled subsystem, which is used to perform multi-stage separation on the input tail gas or purge gas to obtain high-purity hydrogen, high-purity carbon dioxide and carbon monoxide-rich gas stream.

[0023] The high-purity hydrogen is reinjected into the inlet of the methanol synthesis and distillation unit to adjust the hydrogen-to-carbon ratio, the high-purity carbon dioxide is fed into the pyrolysis gasification unit as a gasifying agent, and the carbon monoxide-rich gas stream is returned to the inlet of the syngas treatment unit or directly fed into the methanol synthesis and distillation unit.

[0024] As a preferred technical solution of the present invention, the adaptive thermal management network further includes a medium-low temperature organic Rankine cycle power generation system, whose heat source input end is connected to the medium-low temperature waste heat flow of the methanol synthesis and distillation unit and / or the syngas treatment unit, and whose power output end is connected to the pumps, fans, compressors and control units in the system, so as to realize partial power self-sufficiency of the system.

[0025] As a preferred technical solution of the present invention, the oxygen inlet of the oxygen-enriched furnace is connected to an electrolytic water oxygen production subsystem driven by renewable energy. The hydrogen produced by the electrolytic water oxygen production subsystem is selectively injected into the outlet of the syngas treatment unit or the inlet of the methanol synthesis and distillation unit to supplement the hydrogen source or adjust the hydrogen-to-carbon ratio of the syngas.

[0026] This invention also provides a method for preparing green methanol based on a biomass pyrolysis gasification synthesis system, comprising the following steps:

[0027] After pretreatment of biomass raw materials, pyrolysis and oxygen-enriched gasification are carried out in sequence. During the gasification process, recovered carbon dioxide is introduced as part of the gasification agent to generate crude syngas.

[0028] The crude synthesis gas is purified, subjected to water-gas shift to adjust the hydrogen-to-carbon ratio, and treated to remove acidic gases to obtain synthesis gas that meets the requirements for methanol synthesis.

[0029] The synthesis gas is converted into crude methanol under the action of a catalyst, and then the methanol product is obtained by distillation.

[0030] The carbon dioxide and unreacted gases generated during system operation are captured and separated. The separated carbon dioxide is returned to the pyrolysis gasification step, and the separated effective gases are returned to the front end of the system or reused in the methanol synthesis step.

[0031] The system utilizes an adaptive thermal management network to recover, cascade, and distribute heat within its system.

[0032] Compared with the prior art, the biomass pyrolysis gasification synthesis green methanol system provided by the present invention has at least the following beneficial effects:

[0033] 1. This invention achieves efficient recycling of carbon resources in the biomass-to-methanol process by introducing an integrated carbon capture and recycling unit. During system operation, the carbon dioxide-containing tail gas and purge gas generated by the syngas treatment unit and the methanol synthesis and distillation unit are no longer emitted as waste gas. Instead, they are centrally captured and separated, with at least a portion of the carbon dioxide returned to the pyrolysis gasification unit as a gasifying agent to participate in the reaction. This allows the carbon elements in the biomass feedstock to be transformed and utilized multiple times within the system. This method effectively reduces carbon resource loss and increases the conversion ratio of biomass carbon to methanol products. Compared with traditional biomass-to-methanol processes, it significantly improves the system's carbon atom utilization rate and carbon reduction effect.

[0034] 2. This invention achieves tiered recovery and efficient utilization of thermal energy within the system by constructing an adaptive thermal management network, significantly reducing overall energy consumption. High-temperature, medium-temperature, and low-temperature heat generated during pyrolysis gasification and methanol synthesis are uniformly allocated and utilized in stages within the system through the adaptive thermal management network. High-grade heat is used to drive key reactions or supply important process units, while medium- and low-grade heat is used for power generation or raw material pretreatment, thereby reducing dependence on external energy sources. This end-to-end thermal integration design avoids energy waste caused by dispersed heat recovery or direct emission in traditional processes, significantly improving the overall energy utilization efficiency of the system and enhancing the economics and engineering feasibility of the biomass-to-methanol process.

[0035] 3. This invention improves the stability, flexibility, and adaptability of the system through multi-unit coupled design and intelligent coordinated control. Addressing the diverse sources and fluctuating properties of biomass feedstocks, the system dynamically adjusts the syngas composition through a syngas treatment unit and flexibly recirculates the gas components using a carbon capture and recirculation unit, achieving stable control of the syngas composition. Simultaneously, the intelligent coordinated control center optimizes and regulates the carbon flow, energy flow, and material flow as a whole, ensuring efficient and stable operation under varying feedstock conditions and load changes. This overall collaborative operation mode effectively overcomes the problems of isolated units and local optima in existing technologies, enhancing the long-term reliability and application value of the system. Attached Figure Description

[0036] Figure 1 This invention provides an overall process flow diagram of a biomass pyrolysis gasification synthesis green methanol system;

[0037] Figure 2 This is a core carbon cycle pathway diagram of a biomass pyrolysis gasification synthesis green methanol system proposed in this invention;

[0038] Figure 3 This is a smart coordination control logic diagram of a biomass pyrolysis gasification synthesis green methanol system proposed in this invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with embodiments and appendices. Figures 1-3 The present invention will be further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] The following detailed description, in conjunction with the system structure and operation process of this invention, further illustrates the biomass pyrolysis gasification synthesis of green methanol system and its preparation method. This embodiment aims for continuous and stable system operation, and provides an overall description of the structural configuration, material flow, energy utilization methods, and carbon resource recycling pathways of each functional unit. Those skilled in the art should understand that equivalent adjustments to the equipment configuration, operating parameters, and connection methods made without departing from the overall concept of this invention are all within the scope of protection of this invention.

[0041] The biomass pyrolysis gasification synthesis green methanol system of the present invention is composed of a pyrolysis gasification unit, a syngas treatment unit, and a methanol synthesis and distillation unit connected in sequence. A carbon capture and circulation unit and an adaptive thermal management network are integrated in the periphery of the system. At the same time, a biochar treatment and utilization subsystem and an intelligent coordination and control center are provided to achieve synergistic optimization of the system in terms of carbon utilization rate and energy utilization efficiency.

[0042] During system operation, biomass feedstock first enters the pretreatment section, where it is crushed and screened to form solid feedstock with suitable particle size. The moisture content is then reduced by a drying device to meet the process requirements of subsequent pyrolysis reactions. The heat required for the drying device is not from external energy sources, but is provided by low-grade waste heat recovered from within the system by an adaptive thermal management network, thereby reducing the overall external energy consumption of the system.

[0043] The pretreated biomass feedstock is continuously fed into the moving bed pyrolysis reactor in the pyrolysis and gasification unit. Under anoxic or slightly anoxic conditions, the biomass undergoes pyrolysis at mesophilic temperatures, decomposing into gaseous products and solid biochar. The pyrolysis gas is discharged from the top of the reactor and serves as an important feedstock for subsequent gasification reactions, while the biochar is discharged from the bottom of the reactor and enters the biochar treatment and utilization subsystem.

[0044] The pyrolysis gas produced by pyrolysis then enters an oxygen-enriched gasifier, where it participates in a high-temperature gasification reaction along with carbon dioxide recovered from the integrated carbon capture and recycling unit and oxygen-enriched gas. During this process, carbon dioxide, as part of the gasifying agent, undergoes an endothermic reaction with carbonaceous intermediates to generate carbon monoxide, thus reintroducing carbon resources that were originally emitted at the end of the system into the main reaction process. By adjusting the supply ratio of oxygen and carbon dioxide, the crude syngas exiting the gasifier is made to meet the requirements for subsequent processing in terms of composition and temperature. The crude syngas generated after the gasification reaction is completed has hydrogen and carbon monoxide as its main components, with significantly reduced tar and methane content.

[0045] The high-temperature crude syngas produced by the oxygen-enriched furnace enters the syngas processing unit on one hand, and its sensible heat is recovered through an adaptive thermal management network on the other. The recovered high-temperature heat is preferentially used for high-grade heat demand within the system, while unused heat is further downgraded for use in medium- and low-temperature heat demand units, thereby achieving cascaded utilization of thermal energy.

[0046] The syngas treatment unit sequentially includes a dust removal and tar removal unit, a steam-water shift reactor, and an acid gas removal unit. The crude syngas first enters the dust removal and tar removal unit to remove particulate matter and residual high-boiling-point impurities, obtaining clean gas. Subsequently, the clean syngas enters the steam-water shift reactor, where a controlled amount of water vapor is introduced, causing carbon monoxide to undergo a shift reaction with the water vapor to produce hydrogen and carbon dioxide, thereby dynamically adjusting the hydrogen-to-carbon ratio in the syngas.

[0047] The heat required for the water-steam shift reactor is provided by an adaptive thermal management network from the heat recovered during the methanol synthesis reaction. By coordinating the control of heat flow and steam injection rate, the hydrogen-to-carbon ratio of the syngas is stabilized within a range suitable for the methanol synthesis reaction, reducing dependence on external steam or fuel.

[0048] The syngas after water-gas shift reaction enters the acid gas removal unit, where carbon dioxide and other acidic impurities are selectively removed through a physical-chemical composite absorption process based on phase change absorbers. The high-concentration carbon dioxide gas stream obtained during the removal process is concentrated and transported to the integrated carbon capture and recirculation unit, while the purified syngas enters the methanol synthesis and distillation unit.

[0049] In the methanol synthesis and distillation unit, syngas meeting the composition requirements undergoes a methanol synthesis reaction under the action of a catalyst to produce crude methanol. The heat released during the reaction is continuously removed through an adaptive thermal management network and distributed to the water-gas shift reactor, biomass dryer, or organic Rankine cycle power generation system according to the system's heat load requirements. The crude methanol produced is then separated by distillation to obtain green methanol products that meet product standards. Unreacted gases in the synthesis loop are extracted as purge gases and sent to the integrated carbon capture and recirculation unit.

[0050] The integrated carbon capture and recirculation unit centrally processes the carbon dioxide gas stream from the acid gas removal unit and the purge gas from the methanol synthesis unit. This unit employs a combination of membrane separation and cryogenic distillation to perform multi-stage separation of the mixed gas, yielding high-purity hydrogen, high-purity carbon dioxide, and carbon monoxide-rich gas streams. The high-purity carbon dioxide is pressurized and returned to the pyrolysis gasification unit as a gasifying agent. The high-purity hydrogen and carbon monoxide-rich gas streams are reinjected into the inlet of the syngas treatment unit or the methanol synthesis unit, depending on system operating requirements, to adjust the hydrogen-to-carbon ratio or replenish effective reaction components, thereby minimizing the loss of carbon and hydrogen atoms.

[0051] An adaptive thermal management network runs through all major units of the system, achieving centralized recovery and graded utilization of heat through heat exchangers, heat transfer media, and regulating valve groups. High-temperature heat from the gasifier is preferentially used in high-grade heat-consuming units, while medium- and low-temperature heat from methanol synthesis and distillation processes is used for water-gas shift reactions and organic Rankine cycle power generation. The electricity generated drives pumps, fans, compressors, and control units within the system, thus achieving partial self-sufficiency in electricity. Low-temperature waste heat is further used for the pre-drying of biomass feedstock, significantly reducing the overall energy consumption of the system.

[0052] The biochar treatment and utilization subsystem utilizes the biochar produced by the pyrolysis reaction in a cascade manner. Some of the biochar is activated and used as an adsorbent material in the impurity adsorption process of the syngas treatment unit; the remaining biochar is transported as solid fuel to the self-heating burner in the pyrolysis gasification unit to provide a stable heat source for the pyrolysis reaction, thereby reducing the input of external fuel.

[0053] The entire system is uniformly controlled by an intelligent coordination and control center. The control center collects operating parameters such as raw material characteristics, temperature, pressure, flow rate, and gas composition of each unit in real time, and dynamically optimizes the water-vapor shift reaction intensity, the recirculation ratio of each gas flow in the carbon capture unit, and the heat distribution in the adaptive thermal management network based on the mechanism model and predictive control algorithm, so that the system can always maintain stable and efficient operation under different raw material conditions and load changes.

[0054] Through the above structural configuration and operation mode, this invention achieves the synergistic utilization of biomass resources, carbon dioxide resources, and internal system heat energy, maximizing the conversion of carbon in biomass into methanol products while significantly reducing external energy consumption and carbon emissions. It possesses good engineering feasibility and promotional value.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomass pyrolysis gasification system for synthesizing green methanol, characterized in that, include: The pyrolysis gasification unit, the syngas treatment unit, and the methanol synthesis and distillation unit are connected in sequence. The system includes an integrated carbon capture and recycling unit, which is connected to the tail gas emission end of the syngas treatment unit and / or the purge gas end of the methanol synthesis and distillation unit, and to the inlet end of the pyrolysis gasification unit. The integrated carbon capture and recycling unit is used to capture, separate and reuse carbon dioxide and unreacted gases generated during system operation, so that at least part of the carbon dioxide is returned to the pyrolysis gasification unit as part of the gasification agent. An adaptive thermal management network is used for heat recovery, cascade utilization, and distribution among the pyrolysis gasification unit, the syngas treatment unit, and the methanol synthesis and distillation unit, including at least: using part of the heat from the high-temperature syngas generated by the pyrolysis gasification unit for the pretreatment and drying of biomass feedstock, and using the heat released from the methanol synthesis reaction in the methanol synthesis and distillation unit to provide thermal energy for the water-gas shift reaction or other heat-using units in the syngas treatment unit.

2. The biomass pyrolysis gasification synthesis green methanol system according to claim 1, characterized in that, The pyrolysis gasification unit includes a moving bed pyrolysis reactor and an oxygen-enriched gasification furnace arranged in series. The moving bed pyrolysis reactor is configured to pyrolyze pretreated biomass feedstock under mesotemperature, anoxic or micro-anoxic conditions to generate pyrolysis gas and biochar. The oxygen-enriched gasifier is configured to receive the pyrolysis gas and the carbon dioxide recovered from the integrated carbon capture and recycling unit, and to carry out a high-temperature gasification reaction under oxygen-enriched conditions to generate crude syngas mainly composed of hydrogen and carbon monoxide.

3. The biomass pyrolysis gasification synthesis green methanol system according to claim 2, characterized in that, It also includes a biochar treatment and utilization subsystem, the input of which is connected to the biochar outlet of the moving bed pyrolysis reactor; The biochar treatment and utilization subsystem is configured to activate at least a portion of the biochar and use it as an adsorbent for the impurity removal process in the syngas treatment unit, and / or to transport at least a portion of the biochar as solid fuel to a self-heating burner in the pyrolysis gasification unit to provide heat for the pyrolysis process.

4. The biomass pyrolysis gasification synthesis green methanol system according to claim 1, characterized in that, The syngas treatment unit includes a dust removal and tar removal device, a water-gas shift reactor, and an acid gas removal device connected in sequence; wherein, the water-gas shift reactor is configured to dynamically adjust the hydrogen-to-carbon ratio in the syngas by adjusting the water injection rate and reaction conditions, so that the syngas meets the composition requirements of the methanol synthesis reaction.

5. The biomass pyrolysis gasification synthesis green methanol system according to claim 4, characterized in that, Some or all of the reaction heat required by the water-gas shift reactor is recovered and provided by the adaptive thermal management network from the exothermic reaction of methanol synthesis in the methanol synthesis and distillation unit.

6. The biomass pyrolysis gasification synthesis green methanol system according to claim 4, characterized in that, The acid gas removal device employs a physical-chemical composite absorption process based on phase change absorbents. The high-concentration carbon dioxide gas stream obtained during its regeneration process is transported to the integrated carbon capture and recycling unit.

7. The biomass pyrolysis gasification synthesis green methanol system according to claim 1, characterized in that, The integrated carbon capture and recycling unit includes a membrane separation and cryogenic distillation coupled subsystem, used to perform multi-stage separation on the input tail gas or purge gas to obtain high-purity hydrogen, high-purity carbon dioxide and carbon monoxide-rich gas streams. The high-purity hydrogen is reinjected into the inlet of the methanol synthesis and distillation unit to adjust the hydrogen-to-carbon ratio, the high-purity carbon dioxide is fed into the pyrolysis gasification unit as a gasifying agent, and the carbon monoxide-rich gas stream is returned to the inlet of the syngas treatment unit or directly fed into the methanol synthesis and distillation unit.

8. The biomass pyrolysis gasification synthesis green methanol system according to claim 1, characterized in that, The adaptive thermal management network also includes a medium-low temperature organic Rankine cycle power generation system, whose heat source input is connected to the medium-low temperature waste heat flow of the methanol synthesis and distillation unit and / or the syngas treatment unit, and whose power output is connected to the pumps, fans, compressors and control units in the system, so as to achieve partial power self-sufficiency of the system.

9. The biomass pyrolysis gasification synthesis green methanol system according to claim 2, characterized in that, The oxygen inlet of the oxygen-enriched furnace is connected to an electrolytic water oxygen production subsystem driven by renewable energy. The hydrogen produced by the electrolytic water oxygen production subsystem is selectively injected into the outlet of the syngas treatment unit or the inlet of the methanol synthesis and distillation unit to supplement the hydrogen source or adjust the hydrogen-to-carbon ratio of the syngas.

10. A method for preparing green methanol based on the biomass pyrolysis gasification synthesis green methanol system according to any one of claims 1 to 9, characterized in that, Includes the following steps: After pretreatment of biomass raw materials, pyrolysis and oxygen-enriched gasification are carried out in sequence. During the gasification process, recovered carbon dioxide is introduced as part of the gasification agent to generate crude syngas. The crude synthesis gas is purified, subjected to water-gas shift to adjust the hydrogen-to-carbon ratio, and treated to remove acidic gases to obtain synthesis gas that meets the requirements for methanol synthesis. The synthesis gas is converted into crude methanol under the action of a catalyst, and then the methanol product is obtained by distillation. The carbon dioxide and unreacted gases generated during system operation are captured and separated. The separated carbon dioxide is returned to the pyrolysis gasification step, and the separated effective gases are returned to the front end of the system or reused in the methanol synthesis step. The system utilizes an adaptive thermal management network to recover, cascade, and distribute heat within its system.

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