Method and system for preparing green methanol through biomass recycling

Abstract

The invention relates to the technical field of green methanol production, and provides a method and system for preparing green methanol through biomass recycling, and the method comprises the following steps: desulfurizing generated biogas, separating the desulfurized biogas into CH4-rich gas, and generating synthesis gas from the CH4-rich gas; when no standby hydrogen is supplied, the synthesis gas is sent to a methanol synthesis tower, under the action of a methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate crude methanol, and the crude methanol passes through a methanol rectifying tower to obtain high-purity green methanol; when standby hydrogen is supplied, hydrogen and standby CO2 are mixed with synthesis gas in proportion, the mixture is pressurized and heated after being mixed and then conveyed to a methanol synthesis tower, and under the action of a methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to generate crude methanol; and the crude methanol passes through a methanol rectifying tower to obtain high-purity green methanol. The continuous and stable production of the green methanol can be effectively improved, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of green methanol production, and in particular to a method and system for producing green methanol from biomass resources. Background Art

[0002] As an abundant and renewable resource, the efficient conversion and utilization of biomass is of great significance for promoting the transformation of energy structure and reducing greenhouse gas emissions. It is considered to be one of the most promising green alternative energy sources in the future.

[0003] Nowadays, biomass in many regions is mainly composed of crop straw, livestock manure, and urban organic waste. At present, the main way to utilize biomass in many places is to generate electricity, which is inefficient and uneconomical. In the context of declining subsidies, the business model is no longer sustainable. In the context of lack of utilization, biomass will pollute the environment if not properly handled.

[0004] Nowadays, the development of new energy industry has also reached a bottleneck. The new energy industry is mainly power generation, but it is highly volatile and intermittent. Power consumption is the bottleneck of the development of new energy industry. At present, the downstream industry of non-electric utilization of new energy industry, green hydrogen industry, is also an important direction of global energy transformation and development. However, green hydrogen has high cost, high volatility and unstable production. The stable production, storage, transportation and consumption of hydrogen energy restrict the development of green hydrogen industry.

[0005] At present, the production of green methanol using biomass and green hydrogen as raw materials has attracted widespread attention worldwide. Green methanol has high value. The development of the green methanol industry can not only realize the high-value utilization of biomass resources and solve the difficulties faced by the development of the biomass industry, but also convert the difficult-to-store and transport hydrogen energy into liquid fuel that is easy to store and transport through a large amount of self-consumption of green electricity and green hydrogen, effectively solving the difficulties in the consumption of new energy industries and the storage and transportation of green hydrogen industries, achieving multiple goals at one stroke.

[0006] However, the current green methanol industry mainly uses two methods: biomass gasification + green hydrogen and renewable CO2 + green hydrogen. These methods have high requirements for raw materials, high production costs, large green hydrogen consumption, and high production costs. In addition, the production of methanol from biomass is limited by wind and solar energy, and photovoltaic power generation and wind power generation are unstable. Affected by the volatility of wind and solar power, the power generation is highly volatile and the power output is unstable, which affects the production of hydrogen and causes poor continuous stability of green hydrogen production. This is an important constraint on the production of green methanol, and there is almost no corresponding control system in the green methanol preparation process in the existing technology. Summary of the invention

[0007] The purpose of the present invention is to solve at least one technical problem in the background technology and to provide a method and system for producing green methanol from biomass resources.

[0008] To achieve the above object, the present invention provides a method for producing green methanol from biomass resources, comprising:

[0009] The biomass straw is crushed and then put into a pretreatment device for structural destruction and pretreatment to improve hydrophilicity;

[0010] Putting livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device;

[0011] The mixed slurry is transported to an anaerobic fermentation tank for stirring and decomposition to produce biogas;

[0012] The biogas is sequentially transported to the desulfurization device and the dehydration device for desulfurization and dehydration, and is stored for standby after the desulfurization and dehydration are completed;

[0013] Green electricity is generated through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters an alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use.

[0014] The spare biogas is further desulfurized and separated into high-purity CO2 and CH4-rich gas. The CO2 is stored for standby use, and the CH4-rich gas enters the gas reforming tower, where water vapor and spare oxygen are used as gasification agents to react under high temperature and high pressure to generate synthesis gas.

[0015] When there is no backup hydrogen supply, the synthesis gas is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0016] When there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, and after mixing, they are pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0017] According to one aspect of the present invention, the anaerobic fermentation tank is maintained at 42-55°C by heat exchange of the internal heating coil and the insulation layer, and the mixed slurry is decomposed to produce biogas under the action of anaerobic fermentation microorganisms in the anaerobic fermentation tank;

[0018] The internal heating coil of the anaerobic fermentation tank exchanges heat with hot water, which is produced by supplying part of the green electricity generated by wind power and / or photovoltaic devices to the electric boiler.

[0019] According to one aspect of the present invention, oxygen after electrolysis is precipitated at the anode, enters the gas-liquid separation system and the purification system in sequence for gas-liquid separation and purification treatment, and is then stored in an oxygen storage tank;

[0020] The hydrogen after electrolysis is precipitated at the cathode, enters the gas-liquid separation system and purification system in turn for gas-liquid separation and purification, and is then stored in a hydrogen storage tank.

[0021] According to one aspect of the present invention, the electrolytic cell is equipped with a water-adding alkali preparation system, which prepares a KOH alkaline solution by mixing pure water and pure ash, and replenishes the amount of alkali solution in the electrolytic cell in time according to the amount of alkali solution in the electrolytic cell; in the electrolytic cell, electrical energy is continuously converted into heat, which will gradually increase the temperature of the alkali solution in the electrolytic cell; the electrolytic cell heat exchange system exchanges heat with the return water from the anaerobic fermentation tank and the electrolytic cell alkali solution to maintain the temperature of the electrolytic cell, and the hot water formed after the heat exchange is used to keep the anaerobic fermentation tank warm.

[0022] According to one aspect of the present invention, the standby biogas is further desulfurized, and after further desulfurization, it is separated into high-purity CO2 and CH4-rich gas, CO2 is stored for standby, and the CH4-rich gas enters the gas reforming tower, using water vapor and standby oxygen as gasifying agents, reacting at high temperature and high pressure to generate synthesis gas:

[0023] The spare biogas passes through a biogas fine desulfurization device to reduce the sulfur content to below 30ppb. The biogas after fine desulfurization is subjected to biogas separation to separate part of the CO2 in the biogas, and the biogas is separated into CH4-rich gas and high-purity CO2; the high-purity CO2 is stored in a CO2 storage tank for standby use, and the CH4-rich gas enters a gas reforming tower, using water vapor and pure oxygen as gasifying agents, and reacts at a high temperature and high pressure of 850-1150°C and 3.5-6.5Mpa to generate synthesis gas.

[0024] According to one aspect of the present invention, when there is no backup hydrogen supply, the synthesis gas is pressurized and heated and then transported to a methanol synthesis tower. Under the action of a methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate crude methanol, water and side reaction products. The crude methanol is passed through a methanol distillation tower to obtain high-purity green methanol:

[0025] When there is no backup hydrogen supply, the synthesis gas is pressurized to 6-8Mpa by a compressor, preheated to 250-350℃ by a heat exchanger, and then enters the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate a crude methanol mixture of crude methanol, water and side reaction products, and the crude methanol mixture is separated into gas and liquid by a methanol separator to obtain crude methanol, and the crude methanol is passed through a methanol distillation tower to obtain high-purity green methanol;

[0026] Among them, the unreacted gas in the methanol synthesis process enters the hydrogen recovery device as circulating gas, and then enters the methanol synthesis device after being pressurized by the compressor to continue to participate in methanol synthesis.

[0027] According to one aspect of the present invention, when there is a reserve hydrogen supply, the hydrogen and the reserve CO2 are mixed with the synthesis gas in proportion, and after the mixing, they are pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to generate crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol:

[0028] When there is a backup hydrogen supply, the backup CO2 and backup hydrogen are mixed with the synthesis gas in a volume ratio of CO2:H2=1:3, pressurized to 6-8Mpa by a compressor, and preheated to 250-350°C by a heat exchanger before entering the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate a crude methanol mixture of crude methanol, water and side reaction products, and the crude methanol mixture is separated into gas and liquid by a methanol separator to obtain crude methanol, and the crude methanol is then passed through a methanol distillation tower to obtain high-purity green methanol;

[0029] Among them, the unreacted gas in the methanol synthesis process enters the hydrogen recovery device as circulating gas, and then enters the methanol synthesis device after being pressurized by the compressor to continue to participate in methanol synthesis.

[0030] To achieve the above object, the present invention also provides a system for producing green methanol from biomass resources, comprising:

[0031] The biomass straw pretreatment module crushes the biomass straw and then puts it into the pretreatment device for structural destruction and pretreatment to improve hydrophilicity;

[0032] A mixed slurry forming module is used to put livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device;

[0033] The biogas generation module transports the mixed slurry to the anaerobic fermentation tank for stirring and decomposition to produce biogas;

[0034] The biogas desulfurization and dehydration module transports the biogas to the desulfurization device and the dehydration device in sequence for desulfurization and dehydration, and stores it for standby use after desulfurization and dehydration are completed;

[0035] The hydrogen and oxygen preparation module generates green electricity through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters the alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use.

[0036] The synthesis gas generation module further desulfurizes the spare biogas and separates it into high-purity CO2 and CH4-rich gas after further desulfurization. The CO2 is stored for backup, and the CH4-rich gas enters the gas reforming tower, using water vapor and spare oxygen as gasification agents to react under high temperature and high pressure to generate synthesis gas;

[0037] The hydrogen-free methanol production module, when there is no backup hydrogen supply, pressurizes and heats the synthesis gas and then transports it to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol;

[0038] There is a hydrogen preparation methanol module, when there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, the mixing is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0039] To achieve the above-mentioned purpose, the present invention also provides an electronic device, characterized in that it includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and when the computer program is executed by the processor, the method for producing green methanol from biomass resources as described above is implemented.

[0040] To achieve the above objectives, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for producing green methanol from biomass resources as described above is implemented.

[0041] According to the solution of the present invention, according to the above solution of the present invention, the present invention provides a complete set of green methanol production technology with mature technology and strong flexibility; its biomass adaptability is strong, compared with the biomass gasification technology which requires the use of straw, sawdust and other lignocellulose raw materials with low moisture content, clean and single, the present invention can use the most widely used raw materials such as straw, livestock and poultry manure, and kitchen waste, and raw materials with large moisture fluctuations and high soil and impurity content can be used, and the raw material security is higher;

[0042] The present invention can ensure that the green methanol system can still produce stably without the supply of green hydrogen, and the load rate is maintained at more than 60%. The green methanol production of the present invention is highly flexible and can maintain continuous and stable production at a load of 60%-110%. This technology can adjust the production load at any time based on the volatility and intermittent production of green hydrogen to achieve continuous and stable production of green methanol;

[0043] The present invention has high energy utilization efficiency and low carbon emission. In the process of new energy electrolysis of water to produce hydrogen, about 40% of the electrical energy is converted into low-grade heat source alkali solution at about 90°C in the electrolytic cell. The present invention uses this low-grade heat source cycle for the insulation utilization of biogas (40-55°C) produced by anaerobic fermentation of biomass, especially since my country's biomass is mainly concentrated in the northern region, and currently green methanol projects are mainly concentrated in North China and Northeast China. The present invention can greatly improve energy utilization efficiency;

[0044] Since biogas (methane content is 50-60%) is hydrogen-rich gas, the present invention can reduce the demand for green methanol and green hydrogen by about 20-40% compared with other technologies. The cost of green hydrogen accounts for a high proportion of green methanol, and the present invention can reduce the production cost by about 20-40%.

[0045] The present invention adopts an intelligent control platform, including an automatic information collection platform, a flexible deployment control system, a wind and light prediction system, and a carbon emission intensity calculation system. First, relying on monitoring parameters such as wind power and photovoltaic operation, biogas production, water electrolysis hydrogen production, and green methanol synthesis, the integrated control system is built to achieve unified control and scheduling of various systems, which can effectively coordinate, optimize and monitor the entire process from raw materials to terminal product production; second, based on the system, it makes up for the instability of hydrogen production, overcomes fluctuations, and systematically coordinates and solves the intermittent, volatility and problems of stable biogas production and stable methanol production with new energy power generation and hydrogen production, so as to achieve the most efficient methanol production, ensure continuous stable high-load production of green methanol, and make the entire process reliable, knowable and controllable, reduce costs and increase efficiency; third, according to the detection information of each system, the carbon emission intensity of green methanol products is dynamically monitored in real time, and the working conditions are adjusted in time to avoid the carbon emission intensity of green methanol exceeding the standard and failing to meet the certification requirements.

[0046] The methane-rich gas after biogas separation can be reformed into a large amount of hydrogen in the gas reforming tower with pure oxygen and water vapor as gasification agents, reducing the use of green hydrogen. At the same time, no nitrogen is produced, so that at the same equivalent ratio as air gasification, the amount of gas reacted is reduced, the reaction temperature is increased, the reaction rate is accelerated, the reactor volume is reduced, the thermal efficiency is improved, and the calorific value of the gasified gas is doubled. At the same reaction temperature as air gasification, the oxygen consumption is reduced, the equivalent ratio is reduced, the gas quality is improved, and the scale of the subsequent synthesis gas to methanol synthesis unit is reduced, which can effectively reduce investment and operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The system flow chart schematically shows a method for producing green methanol from biomass resources according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The present invention will now be discussed with reference to exemplary embodiments. It should be understood that the embodiments discussed are only to enable those skilled in the art to better understand and thus implement the present invention, rather than implying any limitation on the scope of the present invention.

[0049] As used herein, the term “including” and variations thereof are to be interpreted as open-ended terms meaning “including, but not limited to.” The term “based on” is to be interpreted as “based, at least in part, on.” The terms “one embodiment” and “an embodiment” are to be interpreted as “at least one embodiment.”

[0050] Figure 1 The system flow diagram of the method for producing green methanol from biomass resources is schematically shown according to an embodiment of the present invention. Figure 1 As shown, the system architecture of the method for realizing green methanol production from biomass resources consists of four parts: biogas production system 1, new energy hydrogen production system 2, green methanol synthesis system 3, and intelligent control platform (not shown in the figure). Among them, the biogas production system includes a biomass crushing system, a wet material receiving tank, a material pump, a feed box, a pretreatment device, a feed pump, an anaerobic fermentation tank, a discharge pump, a biogas desulfurization device, a biogas dehydration device, a biogas storage cabinet, a hot water insulation system, and a solid-liquid separation device. The new energy hydrogen production system includes wind power photovoltaic, electrochemical energy storage, a rectifier transformer, an electrolyzer, a gas-liquid separation system, a purification system, an electrolyzer heat exchange system, and a water addition and alkali system. The green methanol synthesis system includes a biogas fine desulfurization device, a compressor, a biogas separation device, a CO2 storage tank, a green hydrogen storage tank, a gas reforming tower, a methanol synthesis tower, a hydrogen recovery device, a methanol distillation tower, an electric boiler heating system, and a green methanol storage tank.

[0051] Based on the above system architecture, in this embodiment, the method for producing green methanol from biomass resources includes:

[0052] The biomass straw is crushed and then put into a pretreatment device for structural destruction and pretreatment to improve hydrophilicity;

[0053] Putting livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device;

[0054] The mixed slurry is transported to an anaerobic fermentation tank for stirring and decomposition to produce biogas;

[0055] The biogas is sequentially transported to the desulfurization device and the dehydration device for desulfurization and dehydration, and is stored for standby after the desulfurization and dehydration are completed;

[0056] Green electricity is generated through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters an alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use.

[0057] The spare biogas is further desulfurized and separated into high-purity CO2 and CH4-rich gas. The CO2 is stored for standby use, and the CH4-rich gas enters the gas reforming tower, where water vapor and spare oxygen are used as gasification agents to react under high temperature and high pressure to generate synthesis gas.

[0058] When there is no backup hydrogen supply, the synthesis gas is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0059] When there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, and after mixing, they are pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0060] Specifically, in the present embodiment, the biomass straw is crushed into a particle size of 30-50 mm through a crushing system, and this crushing system can adapt to corn straw, rice straw, and wheat straw with a moisture content in the range of 15-75%. In addition, if there is livestock and poultry manure and restaurant kitchen waste, it enters the wet material receiving pool; the crushed straw is weighed through a feed box and enters the pretreatment device, where it is mixed with the slurry in the pretreatment device. After 1-2 days of biological efficient pretreatment, the structural destruction of the straw is promoted, the hydrophilicity is improved, the fermentation is easier to produce biogas, and the scum crusting of the fermentation system is reduced; the material in the wet material receiving pool can also enter the pretreatment device through a material pump, and the straw (livestock and poultry manure, restaurant kitchen waste) entering the pretreatment device forms a uniformly mixed slurry with the slurry in the pretreatment device, and the slurry with the straw is mixed with the slurry in the pretreatment device. The slurry of (livestock and poultry manure, kitchen waste) is transported to the anaerobic fermentation tank through the feed pump. The fermentation tank is equipped with a stirrer. Under the action of the stirrer, the slurry with straw (livestock and poultry manure, kitchen waste) is mixed and contacted with the materials in the anaerobic fermentation tank. The fermentation tank is maintained at 42-55°C through the internal heating coil heat exchange and insulation layer. Under the action of anaerobic fermentation microorganisms in the fermentation tank materials, the straw (livestock and poultry manure, kitchen waste) is decomposed to produce biogas. The hydraulic retention time of straw (livestock and poultry manure, kitchen waste) in the fermentation tank is about 30 days; biogas contains H2S and water vapor. The biogas enters the desulfurization device and the dehydration device in turn through the biogas pipeline at the top of the anaerobic fermentation tank for desulfurization and dehydration. The sulfur content of the biogas after desulfurization is less than 50ppm. The biogas after desulfurization and dehydration enters the biogas storage cabinet for storage, and the biogas in the biogas storage cabinet is transported to the methanol synthesis system. Hot water is 60-80℃ hot water generated by the electrolyzer heat exchange system of the hydrogen production system and the electric boiler heating system of the green methanol synthesis system. It is heat exchanged through the annular hot water pipe set in the anaerobic fermentation tank, and the general outlet water temperature is 50-65℃. The fermentation residue in the anaerobic fermentation tank enters the solid-liquid separation system through the discharge pump and is separated into biogas residue and biogas liquid; most of the biogas liquid is refluxed and mixed with straw (livestock and poultry manure, kitchen waste) and then enters the pretreatment device.

[0061] Green electricity generated by wind power and / or photovoltaic devices provides power for various devices in the system; part of the green electricity is used to supply factory electricity and electric boilers for heating; part of the green electricity enters the rectifier transformer to produce hydrogen, and the remaining green electricity is connected to the grid; green electricity passes through the rectifier transformer to convert AC into DC, and the DC enters the alkaline electrolyzer to electrolyze the water in the alkaline solution in the electrolyzer into oxygen and hydrogen, of which oxygen is precipitated at the anode, enters the gas-liquid separation system and the purification system, and is stored in the oxygen storage tank; hydrogen is produced at the cathode, which is transported to the gas-liquid separation system of hydrogen through a pipeline; in the gas-liquid separation system, the hydrogen removes the moisture in the gas; the hydrogen after moisture removal enters the purification device, and the hydrogen is purified to more than 99.9% and enters the hydrogen storage tank; the water-adding alkali system mixes pure water and soda ash to prepare an alkaline solution of about 30% KOH, and replenishes the amount of alkali solution in the electrolyzer in time according to the situation of the electrolyzer. In the electrolytic cell, about 40% of the electrical energy is continuously converted into heat, which will gradually increase the temperature of the electrolytic cell alkali solution. The electrolytic cell heat exchange system exchanges heat with the return water (50-65°C) from the anaerobic fermentation system with the electrolytic cell alkali solution to maintain the electrolytic cell temperature, and uses the heat exchanged hot water (60-80°C) to keep the anaerobic fermentation system warm.

[0062] The biogas from the biogas production system enters the green methanol synthesis system, and first passes through the biogas fine desulfurization device to reduce the sulfur content in the biogas to below 30ppb. The biogas after fine desulfurization is subjected to the biogas separation device to separate part of the CO2 in the biogas, and the biogas is separated into CH4-rich gas (CH4 volume ratio of about 80%, CO2 gas volume ratio of about 20%) and high-purity CO2 (CO2 gas volume ratio of about 99% or more); the high-purity CO2 is stored in the CO2 storage tank (2.5-5Mpa). The CH4-rich gas enters the gas reforming tower, and uses water vapor and pure oxygen as gasification agents to react at high temperature and high pressure of 850-1150℃ and 3.5-6.5Mpa to generate synthesis gas (CO volume ratio of about 20-27%, CO2 volume ratio of about 5-10%, hydrogen volume ratio of about 60-69%, and methane volume ratio of less than 0.5%).

[0063] In the scenario where green hydrogen is not produced or the generation load is low (i.e. when there is no backup hydrogen supply): the synthesis gas from the gas reforming tower is pressurized to 6-8Mpa by a compressor, and after being preheated to 250-350°C by a heat exchanger, it enters the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The unreacted gas in the methanol synthesis process enters the hydrogen storage device as a circulating gas, and enters the methanol synthesis device after being pressurized by the compressor again, thereby maximizing the utilization of the raw gas. Crude methanol is separated from gas and liquid by a methanol separator to obtain crude methanol, and crude methanol is passed through a methanol distillation tower to obtain high-purity (more than 99.8%) green methanol. The green methanol product is transported to the green methanol storage tank for storage.

[0064] In the absence of green hydrogen supply, biogas is separated into CH4-rich gas and then reformed into syngas, which has a hydrogen-carbon ratio suitable for methanol synthesis and can keep the methanol production system at a production load of more than 60%. Even without the supply of green hydrogen, green methanol can still be produced at a higher load, avoiding the shutdown of the methanol production system and the problem of insufficient economy.

[0065] In the scenario of high-load continuous production of green hydrogen (i.e. when there is a backup hydrogen supply): CO2 from the CO2 storage tank and green hydrogen from the green hydrogen storage tank are mixed with the synthesis gas from the gas reforming tower in a volume ratio of CO2:H2=1:3, pressurized to 6-8Mpa by a compressor, and preheated to 250-350℃ by a heat exchanger before entering the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The unreacted gas in the methanol synthesis process enters the hydrogen storage device as a circulating gas, and enters the methanol synthesis device after being pressurized by the compressor again, thereby maximizing the utilization of the raw gas. Crude methanol is separated from gas and liquid by a methanol separator to obtain crude methanol, and crude methanol is passed through a methanol distillation tower to obtain high-purity (more than 99.8%) green methanol. The green methanol product is transported to the green methanol storage tank for storage.

[0066] In this embodiment, in the intelligent control platform, the wind and solar prediction system can be used to estimate the subsequent wind power / photovoltaic power generation curve and hydrogen production, and control the production and operation load of the water electrolysis device to prepare hydrogen. The intelligent control system formulates production strategies and optimal production loads based on the production of green electricity and the monitoring information of the entire system through intelligent algorithms. During peak power generation, part of the green electricity is stored in electrochemical energy storage, and green electricity is most efficiently used to produce green hydrogen, which is then stored in hydrogen storage tanks. In addition to meeting production electricity needs, the remaining green electricity is connected to the grid; during low power generation, hydrogen is produced through green electricity from electrochemical energy storage, and the green hydrogen in the hydrogen storage tank is released to reduce the volatility of methanol production.

[0067] According to the above scheme of the present invention, the present invention provides a complete set of green methanol production technology with mature technology and strong flexibility; its biomass adaptability is strong. Compared with the biomass gasification technology which requires the use of low-moisture, clean and single lignocellulose raw materials such as straw and sawdust, the present invention can use the most widely used raw materials such as straw, livestock and poultry manure, and kitchen waste. Raw materials with large moisture fluctuations and high soil and impurity content can be used, and the raw material security is higher;

[0068] The present invention can ensure that the green methanol system can still produce stably without the supply of green hydrogen, and the load rate is maintained at more than 60%. The green methanol production of the present invention is highly flexible and can maintain continuous and stable production at a load of 60%-110%. This technology can adjust the production load at any time based on the volatility and intermittent production of green hydrogen to achieve continuous and stable production of green methanol;

[0069] The present invention has high energy utilization efficiency and low carbon emission. In the process of new energy electrolysis of water to produce hydrogen, about 40% of the electrical energy is converted into low-grade heat source alkali solution at about 90°C in the electrolytic cell. The present invention uses this low-grade heat source cycle for the insulation utilization of biogas (40-55°C) produced by anaerobic fermentation of biomass, especially since my country's biomass is mainly concentrated in the northern region, and currently green methanol projects are mainly concentrated in North China and Northeast China. The present invention can greatly improve energy utilization efficiency;

[0070] Since biogas (methane content is 50-60%) is hydrogen-rich gas, the present invention can reduce the demand for green methanol and green hydrogen by about 20-40% compared with other technologies. The cost of green hydrogen accounts for a high proportion of green methanol, and the present invention can reduce the production cost by about 20-40%.

[0071] The present invention adopts an intelligent control platform, including an automatic information collection platform, a flexible deployment control system, a wind and light prediction system, and a carbon emission intensity calculation system. First, relying on monitoring parameters such as wind power and photovoltaic operation, biogas production, water electrolysis hydrogen production, and green methanol synthesis, the integrated control system is built to achieve unified control and scheduling of various systems, which can effectively coordinate, optimize and monitor the entire process from raw materials to terminal product production; second, based on the system, it makes up for the instability of hydrogen production, overcomes fluctuations, and systematically coordinates and solves the intermittent, volatility and problems of stable biogas production and stable methanol production with new energy power generation and hydrogen production, so as to achieve the most efficient methanol production, ensure continuous stable high-load production of green methanol, and make the entire process reliable, knowable and controllable, reduce costs and increase efficiency; third, according to the detection information of each system, the carbon emission intensity of green methanol products is dynamically monitored in real time, and the working conditions are adjusted in time to avoid the carbon emission intensity of green methanol exceeding the standard and failing to meet the certification requirements.

[0072] The methane-rich gas after biogas separation can be reformed into a large amount of hydrogen in the gas reforming tower with pure oxygen and water vapor as gasification agents, reducing the use of green hydrogen. At the same time, no nitrogen is produced, so that at the same equivalent ratio as air gasification, the amount of gas reacted is reduced, the reaction temperature is increased, the reaction rate is accelerated, the reactor volume is reduced, the thermal efficiency is improved, and the calorific value of the gasified gas is doubled. At the same reaction temperature as air gasification, the oxygen consumption is reduced, the equivalent ratio is reduced, the gas quality is improved, and the scale of the subsequent synthesis gas to methanol synthesis unit is reduced, which can effectively reduce investment and operation and maintenance costs.

[0073] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a system for producing green methanol from biomass resources, comprising:

[0074] The biomass straw pretreatment module crushes the biomass straw and then puts it into the pretreatment device for structural destruction and pretreatment to improve hydrophilicity;

[0075] A mixed slurry forming module is used to put livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device;

[0076] The biogas generation module transports the mixed slurry to the anaerobic fermentation tank for stirring and decomposition to produce biogas;

[0077] The biogas desulfurization and dehydration module transports the biogas to the desulfurization device and the dehydration device in sequence for desulfurization and dehydration, and stores it for standby use after desulfurization and dehydration are completed;

[0078] The hydrogen and oxygen preparation module generates green electricity through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters the alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use.

[0079] The synthesis gas generation module further desulfurizes the spare biogas and separates it into high-purity CO2 and CH4-rich gas after further desulfurization. The CO2 is stored for backup, and the CH4-rich gas enters the gas reforming tower, using water vapor and spare oxygen as gasification agents to react under high temperature and high pressure to generate synthesis gas;

[0080] The hydrogen-free methanol production module, when there is no backup hydrogen supply, pressurizes and heats the synthesis gas and then transports it to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol;

[0081] There is a hydrogen preparation methanol module, when there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, the mixing is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

[0082] The system for producing green methanol from biomass resources according to the present invention can realize the method for producing green methanol from biomass resources. The specific method steps are as described above and will not be repeated here.

[0083] Furthermore, to achieve the above objectives, the present invention also provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for producing green methanol from biomass resources as described above is implemented.

[0084] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for producing green methanol from biomass resources as described above is implemented.

[0085] Those skilled in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0086] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method implementation methods, and will not be repeated here.

[0087] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0088] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0089] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0090] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the energy-saving signal sending / receiving method of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0091] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0092] It should be understood that the size of the serial numbers of each step in the content of the invention and the implementation methods of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation methods of the present invention.

Claims

1. A method for producing green methanol from biomass resources, characterized in that: include: The biomass straw is crushed and then put into a pretreatment device for structural destruction and pretreatment to improve hydrophilicity; Putting livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device; The mixed slurry is transported to an anaerobic fermentation tank for stirring and decomposition to produce biogas; The biogas is sequentially transported to the desulfurization device and the dehydration device for desulfurization and dehydration, and is stored for standby after the desulfurization and dehydration are completed; Green electricity is generated through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters an alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use. The spare biogas is further desulfurized and separated into high-purity CO2 and CH4-rich gas. The CO2 is stored for standby use, and the CH4-rich gas enters the gas reforming tower, where water vapor and spare oxygen are used as gasification agents to react under high temperature and high pressure to generate synthesis gas. When there is no backup hydrogen supply, the synthesis gas is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol. When there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, and after mixing, they are pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

2. The method for producing green methanol from biomass resources according to claim 1, characterized in that: The anaerobic fermentation tank is maintained at 42-55°C by heat exchange of the internal heating coil and the insulation layer. Under the action of anaerobic fermentation microorganisms in the anaerobic fermentation tank, the mixed slurry is decomposed to produce biogas; The internal heating coil of the anaerobic fermentation tank exchanges heat with hot water, which is produced by supplying part of the green electricity generated by wind power and / or photovoltaic devices to the electric boiler.

3. The method for producing green methanol from biomass resources according to claim 1, characterized in that: The oxygen after electrolysis is precipitated at the anode, enters the gas-liquid separation system and purification system in turn for gas-liquid separation and purification, and is then stored in an oxygen storage tank; The hydrogen after electrolysis is precipitated at the cathode, enters the gas-liquid separation system and purification system in turn for gas-liquid separation and purification, and is then stored in a hydrogen storage tank.

4. The method for producing green methanol from biomass resources according to claim 1, characterized in that: The electrolytic cell is equipped with a water-adding alkali preparation system, which prepares a KOH alkaline solution by mixing pure water and soda ash, and replenishes the amount of alkali solution in the electrolytic cell in time according to the amount of alkali solution in the electrolytic cell; in the electrolytic cell, electric energy is continuously converted into heat, which gradually increases the temperature of the alkali solution in the electrolytic cell; the electrolytic cell heat exchange system exchanges heat with the return water from the anaerobic fermentation tank and the electrolytic cell alkali solution to maintain the temperature of the electrolytic cell, and the hot water formed after the heat exchange is used for heat insulation of the anaerobic fermentation tank.

5. The method for producing green methanol from biomass resources according to claim 1, characterized in that: The standby biogas is further desulfurized, and after further desulfurization, it is separated into high-purity CO2 and CH4-rich gas, CO2 is stored for standby, and the CH4-rich gas enters the gas reforming tower, using water vapor and standby oxygen as gasifying agents, reacting at high temperature and high pressure to generate synthesis gas: The spare biogas passes through a biogas fine desulfurization device to reduce the sulfur content to below 30ppb. The biogas after fine desulfurization is subjected to biogas separation to separate part of the CO2 in the biogas, and the biogas is separated into CH4-rich gas and high-purity CO2; the high-purity CO2 is stored in a CO2 storage tank for standby use, and the CH4-rich gas enters a gas reforming tower, using water vapor and pure oxygen as gasifying agents, and reacts at a high temperature and high pressure of 850-1150°C and 3.5-6.5Mpa to generate synthesis gas.

6. The method for producing green methanol from biomass resources according to claim 1, characterized in that: When there is no backup hydrogen supply, the synthesis gas is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol: When there is no backup hydrogen supply, the synthesis gas is pressurized to 6-8Mpa by a compressor, preheated to 250-350℃ by a heat exchanger, and then enters the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate a crude methanol mixture of crude methanol, water and side reaction products, and the crude methanol mixture is separated into gas and liquid by a methanol separator to obtain crude methanol, and the crude methanol is passed through a methanol distillation tower to obtain high-purity green methanol; Among them, the unreacted gas in the methanol synthesis process enters the hydrogen recovery device as circulating gas, and then enters the methanol synthesis device after being pressurized by the compressor to continue to participate in methanol synthesis.

7. The method for producing green methanol from biomass resources according to any one of claims 1 to 6, characterized in that: When there is a reserve hydrogen supply, the hydrogen and the reserve CO2 are mixed with the synthesis gas in proportion, and after the mixture is pressurized and heated, it is transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to generate crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol: When there is a backup hydrogen supply, the backup CO2 and backup hydrogen are mixed with the synthesis gas in a volume ratio of CO2:H2=1:3, pressurized to 6-8Mpa by a compressor, and preheated to 250-350°C by a heat exchanger before entering the methanol synthesis tower; under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to generate a crude methanol mixture of crude methanol, water and side reaction products, and the crude methanol mixture is separated into gas and liquid by a methanol separator to obtain crude methanol, and the crude methanol is then passed through a methanol distillation tower to obtain high-purity green methanol; Among them, the unreacted gas in the methanol synthesis process enters the hydrogen recovery device as circulating gas, and then enters the methanol synthesis device after being pressurized by the compressor to continue to participate in methanol synthesis.

8. A system for producing green methanol from biomass resources, characterized in that: include: The biomass straw pretreatment module crushes the biomass straw and then puts it into the pretreatment device for structural destruction and pretreatment to improve hydrophilicity; A mixed slurry forming module is used to put livestock and poultry manure and kitchen waste into a pretreatment device to form a mixed slurry with the crushed straw in the pretreatment device; The biogas generation module transports the mixed slurry to the anaerobic fermentation tank for stirring and decomposition to produce biogas; The biogas desulfurization and dehydration module transports the biogas to the desulfurization device and the dehydration device in sequence for desulfurization and dehydration, and stores it for standby use after desulfurization and dehydration are completed; The hydrogen and oxygen preparation module generates green electricity through wind power and / or photovoltaic devices. The green electricity is converted from AC to DC through a rectifier transformer. The DC enters the alkaline electrolyzer to electrolyze the water in the alkaline solution into oxygen and hydrogen. The oxygen and hydrogen are separated and stored for future use. The synthesis gas generation module further desulfurizes the spare biogas and separates it into high-purity CO2 and CH4-rich gas after further desulfurization. The CO2 is stored for backup, and the CH4-rich gas enters the gas reforming tower, using water vapor and spare oxygen as gasification agents to react under high temperature and high pressure to generate synthesis gas; The hydrogen-free methanol production module, when there is no backup hydrogen supply, pressurizes and heats the synthesis gas and then transports it to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the synthesis gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol; There is a hydrogen preparation methanol module, when there is a backup hydrogen supply, the hydrogen and backup CO2 are mixed with the synthesis gas in proportion, the mixing is pressurized and heated and then transported to the methanol synthesis tower. Under the action of the methanol catalyst in the methanol synthesis tower, the mixed gas reacts in the methanol synthesis tower to produce crude methanol, water and side reaction products. The crude methanol is passed through the methanol distillation tower to obtain high-purity green methanol.

9. An electronic device, characterized in that The method comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for producing green methanol from biomass resources as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for producing green methanol from biomass resources according to any one of claims 1 to 7 is implemented.

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