A methanol production process coupling organic solid waste gasification and water electrolysis hydrogen production

Abstract

The methanol production process of the present invention is achieved by coupling the gasification of organic solid waste with the electrolysis of water to produce hydrogen through the following steps: a) Green hydrogen production, using abandoned wind and photovoltaic energy, valley electricity or H generated by the system's self-electrolysis of water; 2 ; b). Gasification of organic solid waste, using gasifier and combustion furnace to achieve gasification of organic solid waste; c). Purification of raw gas; d). Synthesis of methanol, the volume content of each component of methanol synthesis gas meets (H 2 ‑CO 2 ) / (CO+CO 2 ) = 1.9 ~ 2.3; the tempered synthesis gas is pressurized and then enters the methanol synthesis unit to synthesize methanol. The methanol preparation process of the present invention couples renewable energy systems with various characteristics such as abandoned wind, abandoned solar, and biomass energy, and complements multiple energies, promotes the cross-regional and cross-seasonal optimization of heterogeneous energy, promotes the integration of hydrogen energy, electric energy, and thermal energy systems, and promotes the formation of a modern energy supply system with multiple complementary integration.

Description

Technical Field

[0001] The present invention proposes "a methanol preparation process that couples organic solid waste gasification with water electrolysis to produce hydrogen", uses "green hydrogen" and organic solid waste carbon sources to synthesize methanol, solves the problem of hydrogen storage and transportation, realizes the overall disposal and resource utilization of organic solid waste, couples renewable energy systems with various characteristics such as abandoned wind, abandoned light, and biomass energy, and complements multiple energies, promotes the cross-regional and cross-seasonal optimization of heterogeneous energy, promotes the integration of hydrogen energy, electric energy and thermal energy systems, and promotes the formation of a modern energy supply system with multiple complementary integration. It belongs to the field of new energy and green chemical technology. Background Art

[0002] The global demand for hydrogen is growing rapidly, and new energy storage and hydrogen energy are expected to develop on a large scale and drive fundamental changes in the energy system. In March 2022, the "Medium- and Long-Term Plan for the Development of the Hydrogen Energy Industry (2021-2035)" jointly issued by the National Development and Reform Commission and the National Energy Administration pointed out: "Accelerate the promotion of innovative application demonstration projects of hydrogen energy in transportation, energy storage, power generation, and industry. With green and low-carbon as the principle, strengthen the green supply of hydrogen energy, create a diverse hydrogen energy consumption ecology, and improve my country's energy security level. Give full play to the supporting role of hydrogen energy in carbon peak and carbon neutrality goals."

[0003] However, there are two shortcomings in the development of global hydrogen energy: First, more than 90% of hydrogen is "grey hydrogen" from fossil energy such as coal and natural gas, which is not sustainable and environmentally friendly; second, the technology of producing "green hydrogen" from renewable resources has attracted much attention from all parties due to its zero-carbon emission advantage in the preparation process, but there is a serious mismatch between the production and consumption sites of large-scale "green hydrogen" based on photovoltaic and wind power. The long-distance transportation of renewable electricity is an important step towards the defossilization of global society. In the process of hydrogen production, storage, transportation and use, gaseous hydrogen storage and transportation are currently the main methods, but the cost of hydrogen storage and transportation is high, and the user cost is too high, which will suppress the demand for hydrogen, and in turn suppress the large-scale production of "green hydrogen", resulting in the scale-cost reduction path being blocked. In the long run, the construction of a dedicated pure hydrogen transmission pipeline network requires a completely new layout and construction, with large investments and long cycles.

[0004] Based on the above, a route for large-scale conversion and consumption of renewable energy such as photovoltaic and wind power through "liquid sunshine" methanol energy storage or ammonia hydrogen energy storage has emerged: renewable energy electrolysis of water to produce "green hydrogen", "green hydrogen" and nitrogen or carbon synthesis into ammonia, methanol, methane, synthesis gas, etc., namely Power-to-X process (PtX). Methanol is liquid at room temperature and pressure, has high energy density, is easy to store and transport, and has great potential in green energy carriers and fuels. Especially in the context of "dual carbon", as important carriers of hydrogen and bulk basic chemicals themselves, methanol and ammonia are attracting more and more attention.

[0005] At present, there is no relevant patent describing the green methanol preparation process combining biomass energy and water electrolysis, so this patent invention is proposed. The present invention proposes "a methanol preparation process coupling organic solid waste gasification and water electrolysis hydrogen production", adopts "green hydrogen" and biomass carbon source to synthesize methanol hydrogen carrier, solves the problem of hydrogen storage and transportation, realizes the overall disposal and resource utilization of organic solid waste, couples renewable energy systems with various characteristics such as abandoned wind, abandoned light, and biomass energy, and complements multiple energies, promotes the cross-regional and cross-seasonal optimization of heterogeneous energy, promotes the integration of hydrogen energy, electric energy and thermal energy systems, and promotes the formation of a modern energy supply system with multiple complementary integration. On the other hand, China is the world's largest methanol producer and consumer, and methanol is one of China's most important basic chemical bulk products. Domestic methanol production is mainly based on coal gasification to produce methanol. In large-scale methanol projects, the direct CO2 process emissions of coal-based methanol products are as high as 2 tons of CO2 / ton of methanol, and the energy consumption of electricity, steam, etc. makes the indirect carbon emissions reach 3.4 tons of CO2 / ton of methanol. Reducing process carbon emissions and power carbon emissions in methanol production is the emission reduction goal of the entire coal-to-methanol industry. Energy conservation and emission reduction have become an important goal of China's coal-to-methanol industry. Actively promoting the industrialization and application of green methanol is an important measure to develop low-carbon energy and circular economy, and is of great significance to solving the problem of climate change. The National "14th Five-Year Plan" Industrial Green Development Plan includes green methanol in the green and low-carbon technology promotion and application project. Summary of the invention

[0006] In view of the above situation, the present invention proposes "a methanol preparation process that couples organic solid waste gasification with water electrolysis to produce hydrogen", which uses agricultural and forestry organic solid waste, livestock manure, restaurant kitchen waste, municipal sludge and other organic solid waste as raw materials, with the purpose of producing green methanol. At the same time, it can realize large-scale consumption of fluctuating renewable energy such as wind and light.

[0007] The methanol preparation process of the present invention, which is coupled with gasification of organic solid waste and hydrogen production by electrolysis of water, is characterized by being achieved by the following steps:

[0008] a). Green hydrogen production, using the abandoned wind and photovoltaic energy of wind power generation or photovoltaic power generation system, the grid valley electricity, or the system's self-generated energy as the energy source to electrolyze water, the H2 gas produced by the electrolysis of water is used for the synthesis of methanol in step d), and the produced O2 gas provides an oxidant for the gasification of organic solid waste in step b);

[0009] b) Gasification of organic solid waste: gasification of organic solid waste is achieved by using a gasifier and a combustion furnace. Organic solid waste as raw materials, water vapor as a gasifying agent, a decarbonizing agent, and a high-temperature circulating bed material produced by the combustion furnace as an energy source enter the gasifier, and hydrogen-rich raw gas is prepared by gasification. The circulating bed material enters the combustion furnace;

[0010] In the combustion furnace, O2 gas generated by air or electrolysis of water is used to assist combustion, and the semi-coke in the circulating bed material is burned to produce high-temperature circulating bed material and high-concentration CO2 gas. The circulating bed material is transported to the gasification furnace, and the high-concentration CO2 gas is collected and used for other purposes to achieve carbon capture;

[0011] c). Purification of raw gas: purify the hydrogen-rich raw gas produced by the gasifier to remove tar and dust from the hydrogen-rich raw gas;

[0012] d). Synthesis of methanol. The methanol synthesis gas is mixed and tempered by raw gas. The raw gas at least includes hydrogen-rich raw gas obtained by gasification of organic solid waste after purification and H2 gas produced by electrolysis of water. The volume content of each component of the methanol synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the tempered synthesis gas is pressurized and enters the methanol synthesis unit to synthesize methanol, and the unreacted gas forms the system purge gas.

[0013] The present invention discloses a methanol preparation process that couples organic solid waste gasification with water electrolysis to produce hydrogen. In the gasification unit, a decarbonizer absorbs CO2 to promote the gasification of organic solid waste raw materials to produce hydrogen; the decarbonizer that has absorbed CO2 enters the combustion unit along with semi-coke and circulating bed material, and is calcined and decomposed in the combustion unit to release CO2; the calcined decarbonizer enters the gasification unit again along with the high-temperature circulating bed material, completing a carbonation-calcination cycle reaction process.

[0014] The present invention provides a methanol preparation process that couples organic solid waste gasification with water electrolysis to produce hydrogen. In step b), the organic solid waste is agricultural and forestry organic solid waste, livestock excrement, restaurant kitchen waste or municipal sludge.

[0015] In the methanol production process of the present invention, the decarbonizing agent in step b) is limestone, quicklime or dolomite, or a mixture of any two or more of limestone, quicklime and dolomite.

[0016] The present invention discloses a methanol preparation system that couples organic solid waste gasification with water electrolysis hydrogen production, comprising a water electrolysis unit, a hydrogen storage unit, an oxygen storage unit, a combustion unit, a gasification unit, a purification unit, a mixing and tempering unit, a pressurizing unit and a methanol synthesis unit. The water electrolysis unit uses abandoned wind and solar green electricity, grid valley electricity or system self-generation as energy to electrolyze water. The H2 gas generated by water electrolysis is introduced into the hydrogen storage unit through a pipeline, and the generated Q2 gas is introduced into the oxygen storage unit through a pipeline; the H2 gas stored in the hydrogen storage unit is transported to the mixing and tempering unit through a pipeline, and the Q2 gas stored in the oxygen storage unit is transported to the combustion unit through a pipeline;

[0017] The gasification unit is fed with organic solid waste as raw materials, water vapor as gasifying agent, decarbonizing agent and high-temperature circulating bed material produced by the combustion unit for providing a source of gasification energy. The gasification unit produces hydrogen-rich raw gas and semi-coke composed of H2, CO, CO2, CH4 and tar. The hydrogen-rich raw gas is passed through a pipeline into the air inlet of the purification unit, and the semi-coke is transported to the combustion unit along with the circulating material. The combustion furnace uses O2 gas or air produced by electrolysis of water to assist combustion, and the semi-coke burns in the combustion furnace. The combustion furnace produces high-temperature circulating bed material and high-concentration CO2 gas. The high-temperature circulating bed material produced by the combustion furnace is transported to the gasification furnace, and the produced high-concentration CO2 gas is collected and utilized.

[0018] The purification unit purifies the introduced raw synthesis gas to remove tar and dust in the hydrogen-rich raw gas, and the purified hydrogen-rich raw gas is transported to the mixing and tempering unit through a pipeline; the mixing and tempering unit produces methanol synthesis gas, and the raw gas for preparing the methanol synthesis gas at least includes the hydrogen-rich raw gas produced by the gasifier and the H2 gas produced by the electrolysis of water; the volume content of each component in the mixed and tempered methanol synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the booster unit passes the mixed and pressurized gas into the methanol synthesis unit, and the methanol synthesis unit synthesizes the synthesis gas into the final product methanol, and outputs the purge gas.

[0019] The methanol preparation system coupled with organic solid waste gasification and water electrolysis hydrogen production of the present invention comprises a purge gas and steam power generation system, which is composed of a gas turbine, an air compressor, a generator, a steam turbine, a condenser, a first waste heat boiler and a second waste heat boiler. The purge gas output by the methanol synthesis unit and / or the purified raw synthesis gas output by the purification unit are mixed with the compressed air output by the air compressor and then introduced into the combustion chamber of the gas turbine. The power output shafts of the gas turbine and the steam turbine are connected to the generator shaft to drive the generator to generate electricity, and the electric energy generated by the generator is used for water electrolysis.

[0020] The high-temperature gas inlet of the second waste heat boiler is connected to the air outlet of the combustion chamber of the gas turbine, the high-temperature gas outlet of the second waste heat boiler is connected to the smoke exhaust pipeline, the high-temperature gas inlet of the first waste heat boiler is connected to the air outlet of the combustion unit, and the high-temperature gas outlet of the first waste heat boiler is connected to the CO2 collection pipeline; the steam outlet of the steam turbine is connected to the steam inlet of the second waste heat boiler through the condenser, the steam outlet of the second waste heat boiler is connected to the steam inlet of the first waste heat boiler, and the steam outlet of the first waste heat boiler is connected to the steam inlet of the steam turbine.

[0021] The beneficial effects of the present invention are as follows: the methanol preparation process of the organic solid waste gasification coupled with water electrolysis hydrogen production of the present invention uses the electrolyzer to absorb wind / light and other renewable energy green electricity, grid valley electricity or system self-produced electricity, to provide combustion-supporting O2 gas for organic solid waste gasification and supplement H2 gas for methanol synthesis; organic solid waste self-heating gasification hydrogen-rich raw gas, supplement H2 gas so that the content of each component of the synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3, and the synthesis gas is used to prepare methanol; "green hydrogen" and biomass carbon source are synthesized to prepare methanol, solving the storage and transportation problems of hydrogen energy, realizing large-scale consumption of wind, light and other volatile and intermittent renewable energy, as well as overall consumption and resource utilization of organic solid waste, coupling renewable energy systems with multiple characteristics such as abandoned wind, abandoned light, biomass energy, and multi-energy complementarity, promoting cross-regional and cross-seasonal optimization of heterogeneous energy, promoting the integration of hydrogen energy, electric energy and thermal energy systems, and promoting the formation of a modern energy supply system with diversified complementarity and integration.

[0022] Furthermore, by setting up a purge gas and steam power generation system, the purge gas containing combustible gases (H2, CO, CH4) discharged from the methanol synthesis unit is mixed with compressed air and introduced into the gas turbine, and the gas turbine is used to drive the motor to generate electricity, thereby realizing the reuse of the purge gas; at the same time, the energy carried by the high-temperature flue gas discharged from the gas turbine after combustion is collected by the second waste heat boiler, and then the energy carried by the high-temperature gas discharged from the combustion unit is collected in the first waste heat boiler, and the generated high-temperature and high-pressure steam is introduced into the steam turbine, driving the steam turbine to drive the generator to generate electricity, thereby effectively realizing the recovery and utilization of the heat carried by the high-temperature gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The schematic diagram of the methanol preparation process of the present invention is a process for coupling gasification of organic solid waste with hydrogen production by electrolysis of water;

[0024] Figure 2 The schematic diagram of the methanol production system of the present invention is a coupling of organic solid waste gasification and water electrolysis hydrogen production.

[0025] In the figure: 1 water electrolysis unit, 2 hydrogen storage unit, 3 oxygen storage unit, 4 combustion unit, 5 gasification unit, 6 purification unit, 7 mixing and tempering unit, 8 pressurizing unit, 9 methanol synthesis unit; 10 gas turbine, 11 air compressor, 12 generator, 13 steam turbine, 14 condenser, 15 first waste heat boiler, 16 second waste heat boiler. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] like Figure 1As shown, a schematic diagram of the methanol preparation process of the invention by coupling organic solid waste gasification with water electrolysis to produce hydrogen is provided, which is achieved through the following steps:

[0028] a). Green hydrogen production, using the abandoned wind and photovoltaic energy of wind power generation or photovoltaic power generation system, the grid valley electricity, or the system's self-generated energy as the energy source to electrolyze water, the H2 gas produced by the electrolysis of water is used for the synthesis of methanol in step d), and the produced O2 gas provides an oxidant for the gasification of organic solid waste in step b);

[0029] b) Gasification of organic solid waste: gasification of organic solid waste is achieved by using a gasifier and a combustion furnace. Organic solid waste as raw materials, water vapor as a gasifying agent, a decarbonizing agent, and a high-temperature circulating bed material produced by the combustion furnace as an energy source enter the gasifier, and hydrogen-rich raw gas is prepared by gasification. The circulating bed material enters the combustion furnace;

[0030] The combustion furnace uses the semi-coke in the high-temperature circulating bed material as fuel, and uses the O2 gas or air generated by electrolysis of water to assist combustion, to produce high-temperature circulating bed material and high-concentration CO2 gas. The high-temperature circulating bed material generated by the combustion furnace is transported to the gasification furnace, and the high-concentration CO2 gas generated is collected and used for other purposes to achieve carbon capture;

[0031] c). Purification of raw gas: purify the hydrogen-rich raw gas produced by the gasifier to remove tar and dust from the hydrogen-rich raw gas;

[0032] d). Synthesis of methanol. The methanol synthesis gas is mixed and tempered by raw gas. The raw gas at least includes hydrogen-rich raw gas obtained by gasification of organic solid waste after purification and H2 gas produced by electrolysis of water. The volume content of each component in the methanol synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the tempered synthesis gas is pressurized and enters the methanol synthesis unit to synthesize methanol, and the unreacted gas forms the system purge gas.

[0033] Since photovoltaic and wind power generation are intermittent, volatile and random, the electricity they generate often cannot be normally incorporated into the power grid, which results in the existence of abandoned wind and photovoltaic energy. The methanol preparation process of the present invention utilizes abandoned wind and photovoltaic energy to electrolyze water, and realizes green hydrogen production while absorbing abandoned wind and photovoltaic energy. It is also possible to utilize electricity during the trough period of the power grid, or utilize electricity generated by the exhaust gas generated by the methanol preparation process of the present invention to electrolyze water to produce hydrogen.

[0034] The methanol preparation process of the present invention, which couples the gasification of organic solid waste with the electrolysis of water to produce hydrogen, on the one hand, electrolyzes water to produce O2 gas and H2 gas: the electrical energy is consumed to provide combustion-supporting O2 gas for the gasification of organic solid waste and to supplement H2 gas for methanol synthesis; on the other hand, in the gasification unit 5, the organic solid waste raw materials undergo a gasification reaction with water vapor as a gasifying agent to generate a crude synthesis gas containing H2, CO, CO2, CH4, tar, and semi-coke; the high-temperature circulating bed material from the combustion unit 4 enters the gasification unit 5 to provide energy for the gasification of the organic solid waste raw materials. The crude synthesis gas produced by gasification of organic solid waste raw materials enters the purification unit 6 to remove impurities such as tar and dust, and the semi-coke enters the combustion unit 4 with the circulating bed material; the air or O2 gas from the oxygen storage unit 3 is introduced into the combustion unit 4, and the semi-coke combustion releases heat to heat the circulating bed material, while generating high-concentration CO2 gas; the purified crude synthesis gas is mixed with the H2 gas from the hydrogen storage unit 2 so that the content of each component after mixing meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the mixed gas is pressurized and enters the methanol synthesis unit 9 to synthesize methanol, and the unreacted gas forms the purge gas.

[0035] like Figure 2 As shown, a schematic diagram of a methanol preparation system for coupling gasification of organic solid waste with electrolytic water hydrogen production of the present invention is given. The methanol preparation system shown is composed of an electrolytic water unit 1, a hydrogen storage unit 2, an oxygen storage unit 3, a combustion unit 4, a gasification unit 5, a purification unit 6, a mixed conditioning unit 7, a pressurization unit 8, and a methanol synthesis unit 9. The electrolytic water unit 1 shown uses abandoned wind and photovoltaic energy, electricity during the grid valley period, or self-generated electricity of the system to electrolyze water to maximize green hydrogen production. The H2 gas outlet and the O2 gas outlet of the electrolytic water unit 1 are respectively connected to the hydrogen storage unit 2 and the oxygen storage unit 3 through pipelines, so that the H2 and O2 generated by the electrolytic water are respectively introduced into the hydrogen storage unit 2 and the oxygen storage unit 3 for temporary storage. The hydrogen storage unit 2 shown is connected to the mixed conditioning unit 7 through a pipeline, so that H2 is introduced into the mixed conditioning unit 7; the oxygen storage unit 3 is connected to the air inlet of the combustion unit 4 through a pipeline, so that O2 is introduced into the combustion unit 4 to flame retard the semi-coke.

[0036] The combustion unit 4 and gasification unit 5 shown in the figure use a combustion furnace and a gasification furnace respectively. Organic solid waste as raw materials, water vapor as gasifying agent, decarbonizing agent (limestone or quicklime) and high-temperature circulating bed material generated by the combustion furnace unit 4 are introduced into the gasification unit. When the high-temperature circulating bed material generated by the combustion furnace unit 4 is used as an energy source, the organic solid waste and water vapor generate a crude synthesis gas composed of H2, CO, CO2, CH4 and tar and semi-coke under high temperature conditions. At the same time, the decarbonizing agent absorbs CO2, further promoting the gasification of organic solid waste raw materials to produce hydrogen; the semi-coke produced enters the combustion unit 4 along with the decarbonizing agent and circulating bed material that absorb CO2. In the combustion unit 4, the semi-coke entering along with the high-temperature circulating bed material is used as fuel, and the O2 gas or air introduced into the oxygen storage unit 3 assists combustion, so that the decarbonizing agent releases CO2. The decarbonizing agent that releases CO2 enters the gasification unit 5 together with the high-temperature circulating bed material. The high-concentration CO2 released by the combustion unit 4 is collected and used for other purposes to achieve CO2 capture.

[0037] The gas outlet of the gasification unit 5 is connected to the gas inlet of the purification unit 6 through a pipeline, and the gas outlet of the purification unit 6 is connected to the gas inlet of the mixing and tempering unit 7. The purification unit 6 purifies the raw gas introduced, removes tar and dust in the raw synthesis gas, and the purified raw synthesis gas is introduced into the mixing and tempering unit 7, and the volume content of each component in the mixed gas is adjusted to meet the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3.

[0038] The gas outlet of the mixed conditioning unit 7 is connected to the gas inlet of the booster unit 8 through a pipeline, and the gas outlet of the booster unit 8 is connected to the gas inlet of the methanol synthesis unit 9. The booster unit 8 boosts the synthesis gas output by the mixed conditioning unit 7 and then passes it into the methanol synthesis unit 9. The pressurized synthesis gas generates methanol in the methanol synthesis unit 9, and the unreacted gas forms the purge gas.

[0039] Since the purge gas output by the methanol synthesis unit 9 contains combustible gases such as CO, H2 and CH4, direct discharge will cause waste and pollute the environment; at the same time, the gas containing high concentration of CO2 discharged by the combustion unit 4 has a very high temperature (above 800°C), and if CO2 is collected directly, it will also cause waste of heat energy. Therefore, a purge gas and steam power generation system is added to realize the utilization of combustible gas energy and high-temperature CO2 exhaust energy.

[0040] The purge gas and steam power generation system shown is composed of a gas turbine 10, a steam turbine 13, an air compressor 11, a generator 12, a condenser 14, a first waste heat boiler 15 and a second waste heat boiler 16; the air compressor 11 generates high-pressure air, and the purge gas generated by the methanol synthesis unit 9 and / or the purified raw synthesis gas output by the purification unit 6 are mixed with the high-pressure air output by the air compressor 11 and then introduced into the combustion chamber of the gas turbine 10, and the gas turbine 10 is driven to work by burning the combustible gas. The power output of the gas turbine 10 and the steam turbine 13 is used to drive the generator 12 to generate electricity, and the electricity generated by the generator 12 is used to electrolyze water to produce hydrogen.

[0041] The gas outlet of the combustion chamber of the gas turbine 10 is connected to the high-temperature gas inlet of the second waste heat boiler 16 through a pipeline, and the high-temperature gas outlet of the second waste heat boiler 16 is connected to the exhaust pipe. The high-temperature gas inlet of the first waste heat boiler 15 is connected to the gas outlet of the combustion unit 4, and the high-temperature gas outlet of the first waste heat boiler 15 is connected to the CO2 collection pipeline. The steam outlet of the steam turbine 13 is condensed by the condenser 14 and then passed to the steam (circulating water) inlet of the second waste heat boiler 16. The high-temperature gas discharged from the gas turbine 10 after combustion will gasify the circulating water in the second waste heat boiler 16, so as to realize the collection of heat in the exhaust gas of the gas turbine 10.

[0042] The water vapor discharged from the second waste heat boiler 16 is introduced into the steam inlet of the first waste heat boiler 15, and the high-temperature gas discharged from the combustion unit 4 further increases the temperature of the water vapor. The heated water vapor is introduced into the steam turbine 13 through the steam outlet of the first waste heat boiler 15 to drive the steam turbine 13 to work, thereby driving the generator 12 to generate electricity.

[0043] In summary, the methanol preparation process of the present invention, which is coupled with gasification of organic solid waste and hydrogen production by water electrolysis, has the following characteristics:

[0044] (1) It has achieved the coupling and multi-energy complementarity of renewable energy systems with various characteristics, such as wind power, solar power, and biomass energy, promoted the cross-regional and cross-seasonal optimization of heterogeneous energy, promoted the integration of hydrogen energy (methanol hydrogen carrier), electric energy, and thermal energy systems, and promoted the formation of a modern energy consumption and supply system with multiple complementary integration;

[0045] (2) Convert the hydrogen storage produced by electrolysis of water from abandoned wind and solar power into methanol storage. Methanol is in liquid state under normal conditions, with stable physical and chemical properties and much greater energy density per unit volume than gaseous H2. Compared with high-cost gaseous hydrogen storage and immature liquid hydrogen storage, methanol storage has improved safety and reduced costs, making it easier to absorb intermittent and fluctuating renewable energy on a large scale, improving the flexibility and stability of the power grid; it is also easier to transport and distribute over long distances, promoting the spatial and temporal redistribution of renewable energy, and is another way to transport energy on a large scale besides (ultra-) high voltage power transmission. Green methanol can help green electricity establish industrial links with industries, construction, and transportation sectors that are difficult to decarbonize deeply, continuously enrich the application scenarios of renewable energy, support the larger-scale development of renewable energy, and drive trillions of dollars of emerging industries; the hydropower, wind power, photovoltaic, and organic solid waste gasification power generation industries that have been abandoned and fully utilized will in turn further stimulate the rapid development of green hydrogen production from electrolysis of water from green electricity on a larger scale. ;

[0046] (3) Use organic solid wastes such as agricultural and forestry solid wastes, livestock and poultry manure, kitchen waste, municipal sludge, etc. as raw materials to produce hydrogen-rich raw gas as a carbon source and provide part of the H2 gas, and use green electricity to electrolyze water to supplement the H2 gas to obtain synthesis gas suitable for methanol production. While absorbing large-scale renewable energy such as abandoned wind and abandoned solar power, it also realizes the resource utilization of organic solid waste;

[0047] A new green methanol preparation process has been realized. Green methanol technology will promote and force industrial upgrading and technological progress. With the continuous progress of renewable energy power generation technologies such as solar energy, wind energy, and hydropower, as well as water electrolysis technology, and the scale effect of water electrolysis hydrogen production technology, the cost of green hydrogen energy has gradually decreased. In particular, with the benefits of carbon emission rights trading from carbon dioxide emission reduction, green methanol will become more and more popular among enterprises and become an important technical path to achieve the goal of carbon neutrality. Promote the upgrading of the energy consumption system and drive the comprehensive green transformation of production and lifestyle.

Claims

1. A methanol production process coupling organic solid waste gasification and water electrolysis hydrogen production, characterized in that: This is accomplished by following these steps: a). Green hydrogen production, using the abandoned wind and photovoltaic energy of wind power generation or photovoltaic power generation system, the grid valley electricity, or the system's self-generated energy as the energy source to electrolyze water, the H2 gas produced by the electrolysis of water is used for the synthesis of methanol in step d), and the produced O2 gas provides an oxidant for the gasification of organic solid waste in step b); b) Gasification of organic solid waste. Gasification of organic solid waste is achieved by using a gasifier and a combustion furnace. Organic solid waste as raw materials, water vapor as a gasifying agent, a decarbonizing agent, and a high-temperature circulating bed material produced by the combustion furnace as an energy source enter the gasifier, and hydrogen-rich raw gas is prepared by gasification. The circulating bed material enters the combustion furnace; in the combustion furnace, O2 gas produced by air or electrolysis of water is used to assist combustion, and semi-coke in the circulating bed material is burned to produce high-temperature circulating bed material and high-concentration CO2 gas. The circulating bed material is transported to the gasifier, and the high-concentration CO2 gas is collected and used for other purposes to achieve carbon capture; The organic solid waste in step b) is agricultural and forestry organic solid waste, livestock manure, restaurant kitchen waste or municipal sludge; The decarbonizing agent described in step b) is limestone, quicklime or dolomite, or a mixture of any two or more of limestone, quicklime and dolomite; c). Purification of raw gas: purify the hydrogen-rich raw gas produced by the gasifier to remove tar and dust; d) Synthesis of methanol, the methanol synthesis gas is mixed and tempered by raw gas, the raw gas at least includes the purified hydrogen-rich raw gas obtained by gasification of organic solid waste and H2 gas produced by electrolysis of water, and the volume content of each component of the methanol synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the tempered synthesis gas is pressurized and enters the methanol synthesis unit to synthesize methanol, and the unreacted gas forms the system purge gas; The methanol preparation system comprises a water electrolysis unit (1), a hydrogen storage unit (2), an oxygen storage unit (3), a combustion unit (4), a gasification unit (5), a purification unit (6), a mixing and tempering unit (7), a pressurizing unit (8) and a methanol synthesis unit (9). The water electrolysis unit uses abandoned wind and solar power green electricity, grid off-peak electricity or system self-generation as energy to electrolyze water. The H2 gas generated by the water electrolysis is introduced into the hydrogen storage unit through a pipeline, and the O2 gas generated is introduced into the oxygen storage unit through a pipeline. The H2 gas stored in the hydrogen storage unit is transported to the mixing and tempering unit through a pipeline, and the O2 gas stored in the oxygen storage unit is transported to the combustion unit through a pipeline. The gasification unit is fed with organic solid waste as raw materials, water vapor as gasifying agent, decarbonizing agent and high-temperature circulating bed material produced by the combustion unit for providing a source of gasification energy. The gasification unit produces hydrogen-rich raw gas and semi-coke composed of H2, CO, CO2, CH4 and tar. The hydrogen-rich raw gas is passed through a pipeline into the air inlet of the purification unit, and the semi-coke is transported to the combustion unit along with the circulating material. The combustion furnace uses O2 gas or air produced by electrolysis of water to assist combustion, and the semi-coke burns in the combustion furnace. The combustion furnace produces high-temperature circulating bed material and high-concentration CO2 gas. The high-temperature circulating bed material produced by the combustion furnace is transported to the gasification furnace, and the produced high-concentration CO2 gas is collected and utilized. The purification unit purifies the hydrogen-rich raw gas introduced to remove tar and dust in the hydrogen-rich raw gas, and the purified hydrogen-rich raw gas is transported to the mixing and tempering unit through a pipeline; the mixing and tempering unit produces methanol synthesis gas, and the raw gas for preparing the methanol synthesis gas at least includes the hydrogen-rich raw gas produced by the gasifier and the H2 gas produced by the electrolysis of water; the volume content of each component in the mixed and tempered methanol synthesis gas meets the requirement of (H2-CO2) / (CO+CO2)=1.9~2.3; the boosting unit boosts the mixed synthesis gas and then introduces it into the methanol synthesis unit, and the methanol synthesis unit synthesizes the synthesis gas into the final product methanol, and outputs the purge gas; The self-generated power of the system is a purge gas and steam power generation system, which is composed of a gas turbine (10), an air compressor (11), a generator (12), a steam turbine (13), a condenser (14), a first waste heat boiler (15) and a second waste heat boiler (16). The purge gas output by the methanol synthesis unit and / or the purified raw synthesis gas output by the purification unit are mixed with the compressed air output by the air compressor and then introduced into the combustion chamber of the gas turbine. The power output shafts of the gas turbine and the steam turbine are connected to the generator shaft to drive the generator to generate electricity. The generator The generated electric energy is used for electrolysis of water; the high-temperature gas inlet of the second waste heat boiler is connected to the air outlet of the combustion chamber of the gas turbine, the high-temperature gas outlet of the second waste heat boiler is connected to the smoke exhaust pipeline, the high-temperature gas inlet of the first waste heat boiler is connected to the air outlet of the combustion unit, and the high-temperature gas outlet of the first waste heat boiler is connected to the CO2 collection pipeline; the steam outlet of the steam turbine is connected to the steam inlet of the second waste heat boiler through the condenser, the steam outlet of the second waste heat boiler is connected to the steam inlet of the first waste heat boiler, and the steam outlet of the first waste heat boiler is connected to the steam inlet of the steam turbine.

2. The methanol production process of coupling organic solid waste gasification and water electrolysis hydrogen production according to claim 1 is characterized by: In the gasification unit (5), the decarbonizer absorbs CO2 to promote the gasification of organic solid waste raw materials to produce hydrogen; the decarbonizer that has absorbed CO2 enters the combustion unit (4) along with the semi-coke and circulating bed material, and is calcined and decomposed in the combustion unit to release CO2; the calcined decarbonizer enters the gasification unit (5) again along with the high-temperature circulating bed material, completing a carbonation-calcination cycle reaction process.

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