System and method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen

Abstract

The invention discloses a system and a method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, and relates to the technical field of coal chemical industry. The coal gasification, low-carbon-hydrogen and green-hydrogen coupling methanol and ammonia co-production system comprises a coal gasification unit, a carbon dioxide electrolysis unit, a low-carbon-hydrogen preparation unit, a green-hydrogen preparation unit, an air separation unit, a methanol preparation unit and an ammonia preparation unit. According to the method, chemicals are directly synthesized through low-hydrocarbon and green-hydrogen coupling advanced coal gasification, hydrocarbon balance in the coal-based chemical process is achieved, the energy efficiency and the carbon efficiency in the coal utilization process are greatly improved, carbon emission is remarkably reduced, and the carbon emission is reduced from the source. The method solves the problem of more carbon and less hydrogen in methanol production from coal synthesis gas, realizes green production and reliable supply of hydrogen and cyclic utilization of carbon dioxide, realizes zero carbon emission, and realizes full utilization of coal resources and efficient absorption and utilization of new energy electric energy.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology, and in particular to a system and method for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen. Background Art

[0002] Coal is a resource rich in carbon. Coal chemical industry refers to the process of converting coal into gas, liquid, solid fuel and chemicals through chemical processing using coal as raw material. Coal gasification is one of the important processes in coal chemical industry. It refers to the process in which solid fuels such as coal or coke and semi-coke react with gasifying agents under high temperature, normal pressure or pressurized conditions to convert into gas products and a small amount of residue. During the coal gasification process, a series of homogeneous and heterogeneous chemical reactions occur between the gasifying agent (mainly water vapor, air or oxygen and their mixed gases) and coal. Coal gasification technology is an important technology for achieving deep conversion of coal and industrialization of coal chemical industry. The gasification furnace types that have been commercialized include atmospheric fixed bed gasifier, Texaco pressurized fluidized flow water-coal slurry gasifier with liquid slag discharge, Shell pressurized fluidized flow dry pulverized coal gasifier with liquid slag discharge and GSP pressurized fluidized flow dry pulverized coal gasifier. The gas products of coal gasification can be used as industrial kiln gas, city gas, or used to make synthesis gas, as a raw material for synthetic ammonia, synthetic methanol and synthetic liquid fuel. The hydrogen and oxygen content in coal is low, which leads to the fact that coal-based synthesis gas has the characteristics of more carbon and less hydrogen. When using coal-based synthesis gas to produce methanol, in order to obtain synthesis gas that meets the appropriate carbon-hydrogen ratio, a water-gas shift operation is often required. The water-gas shift operation adjusts the carbon-hydrogen ratio and causes large amounts of CO2 emissions, resulting in a serious waste of CO2 resources.

[0003] Hydrogen energy is divided into three types: gray hydrogen, blue hydrogen (low-carbon hydrogen) and green hydrogen according to the production method and carbon emissions. Low-carbon hydrogen refers to a type of hydrogen that reduces greenhouse gas emissions during the hydrogen production process through various technical means (such as carbon capture and storage, carbon neutrality, etc.). The carbon emissions of low-carbon hydrogen are relative to traditional gray hydrogen. Green hydrogen is hydrogen produced by electrolyzing water through renewable energy (such as solar energy, wind energy, etc.). The production process of green hydrogen does not produce carbon emissions, and its raw materials (water) are widely available.

[0004] The western region of my country is rich in renewable resources such as wind energy and solar energy, which provide unique conditions for power generation. At present, wind power generation projects and photovoltaic power generation projects in the western region have formed a large scale and are showing a trend of large-scale bases. These renewable resource power generation projects not only help reduce dependence on and consumption of traditional energy, but also effectively reduce carbon emissions and promote the development of green energy. Summary of the invention

[0005] The purpose of the present invention is to address the problem of large CO2 emissions in the traditional coal-based chemical production process, and to provide a system and method for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen. By coupling low-carbon hydrogen and green hydrogen with advanced coal gasification to directly synthesize chemicals, the energy efficiency and carbon efficiency of the coal utilization process can be greatly improved, and carbon emissions can be significantly reduced, thereby reducing carbon emissions from the source.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: In the first aspect, the present invention proposes a system for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, comprising: The coal gasification unit is used for gasification reaction of water-coal slurry, oxygen and water vapor to generate crude synthesis gas, and desulfurize and remove carbon dioxide from the crude synthesis gas to obtain refined synthesis gas; Carbon dioxide electrolysis unit, used for electrolysis of carbon dioxide and water to generate electrolytic synthesis gas and oxygen, Low-carbon hydrogen production unit, used to separate the tail gas from methanol cracking and hydrogen production by pressure swing adsorption to obtain hydrogen and carbon dioxide; Green hydrogen production unit, used to electrolyze water to produce oxygen and hydrogen; Air separation unit, used to separate air into oxygen and nitrogen; Methanol preparation unit, used to produce methanol after adjusting the synthesis gas to a suitable carbon-hydrogen ratio; An ammonia preparation unit, used to produce ammonia after adjusting nitrogen and hydrogen to a suitable carbon-hydrogen ratio; The oxygen generated by the green hydrogen production unit, the oxygen generated by the air separation unit, and the oxygen generated by the carbon dioxide electrolysis unit are all fed into the coal gasification unit, the carbon dioxide separated by the low-carbon hydrogen production unit and the carbon dioxide removed from the coal gasification unit are all fed into the carbon dioxide electrolysis unit, the hydrogen generated by the green hydrogen production unit and the hydrogen generated by the low-carbon hydrogen production unit are connected and fed into the methanol preparation unit and the ammonia preparation unit respectively, the refined synthesis gas obtained by the coal gasification unit and the electrolytic synthesis gas obtained by the carbon dioxide electrolysis unit are connected and fed into the methanol preparation unit, and the nitrogen obtained by the air separation unit is fed into the ammonia preparation unit. Furthermore, the coal gasification unit includes a Texaco coal gasification furnace, a desulfurization tower, and a first pressure swing adsorption tower arranged in sequence; the carbon dioxide electrolysis unit includes a carbon dioxide electrolysis cell; the low-carbon hydrogen production unit includes a second pressure swing adsorption tower; the green hydrogen production unit includes a water electrolysis cell; the air separation unit includes an air separation unit; the methanol preparation unit includes a first gas ratio adjustment device and a methanol synthesis tower arranged in sequence; the ammonia preparation unit includes a second gas ratio adjustment device and an ammonia synthesis tower arranged in sequence; the oxygen outlet of the water electrolysis cell, the oxygen outlet of the air separation unit, the second pressure swing adsorption tower; The oxygen outlet of the carbon dioxide electrolysis cell is connected to the oxygen inlet of the Texaco coal gasifier, the carbon dioxide outlet of the first pressure swing adsorption tower and the carbon dioxide outlet of the second pressure swing adsorption tower are connected to the carbon dioxide inlet of the carbon dioxide electrolysis cell, the hydrogen outlet of the water electrolysis cell and the hydrogen outlet of the second pressure swing adsorption tower are connected to the first gas ratio regulation device and the second gas ratio regulation device after being connected in parallel, the synthesis gas outlet of the first pressure swing adsorption tower and the electrolysis synthesis gas outlet of the carbon dioxide electrolysis cell are connected to the first gas ratio regulation device after being connected in parallel, and the nitrogen outlet of the air separation unit is connected to the second gas ratio regulation device.

[0007] The present invention also provides a method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, comprising: (1) The tail gas from methanol cracking to produce hydrogen is sent to the second pressure swing adsorption tower to separate hydrogen and carbon dioxide. At the same time, the electricity generated by wind power and solar power generation is supplied to the carbon dioxide electrolysis cell, the water electrolysis cell, and the air separation unit. External water and the carbon dioxide separated from the second pressure swing adsorption tower are sent to the carbon dioxide electrolysis cell for electrolysis to generate electrolytic synthesis gas and oxygen. External water is sent to the water electrolysis cell for electrolysis to generate hydrogen and oxygen. Air is sent to the air separation unit to separate oxygen and nitrogen. (2) The water-coal slurry and water vapor are fed into the Texaco coal gasifier, and the oxygen generated by the water electrolysis cell, the air separation unit, and the carbon dioxide electrolysis cell is fed into the Texaco coal gasifier to generate a crude synthesis gas. The crude synthesis gas is passed through a desulfurization tower to remove hydrogen sulfide, and then passed through a first pressure swing adsorption tower to separate carbon dioxide to obtain a refined synthesis gas; (3) The carbon dioxide separated from the first pressure swing adsorption tower is fed into the carbon dioxide electrolysis cell, and the refined synthesis gas separated from the first pressure swing adsorption tower is electrolyzed with the carbon dioxide electrolysis cell to generate electrolytic synthesis gas, which is fed into the first gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated from the second pressure swing adsorption tower are fed into the first gas ratio adjustment device. The first gas ratio adjustment device adjusts the carbon-hydrogen ratio to obtain the synthesis gas with a suitable carbon-hydrogen ratio, and then feeds it into the methanol synthesis tower for methanol production. (4) The nitrogen separated by the air separation unit is sent to the second gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated by the second pressure swing adsorption tower are sent to the second gas ratio adjustment device. The second gas ratio adjustment device adjusts the nitrogen-hydrogen ratio to obtain a mixed gas with a suitable nitrogen-hydrogen ratio and then sends it to the ammonia synthesis tower for ammonia production.

[0008] Furthermore, the water electrolysis cell adopts a solid oxide electrolysis cell, the cathode material adopts a Ni-YSZ metal ceramic composite material, the anode material adopts strontium-doped lanthanum gallate, the operating temperature is 600° C., and the operating voltage is 1.3V.

[0009] Furthermore, the carbon dioxide electrolysis cell adopts a solid oxide electrolysis cell, the cathode material adopts vanadium-doped lanthanum strontium iron composite gadolinium-doped cerium oxide, the anode material adopts iridium oxide, the operating temperature is 800° C., and the operating voltage is 1.5V.

[0010] Furthermore, the desulfurizing agent used in the desulfurizing tower is iron oxide.

[0011] Furthermore, the number of the first pressure swing adsorption towers is 3, and the number of the second pressure swing adsorption towers is 5.

[0012] Furthermore, the first gas ratio adjustment device adjusts the molar ratio of CO to H2 to 0.465-0.485.

[0013] Furthermore, the second gas ratio adjustment device adjusts the molar ratio of N2 to H2 to 0.355-0.455.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are: (1) The system and method for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen provided by the present invention directly synthesizes chemicals through coupling low-carbon hydrogen and green hydrogen with advanced coal gasification, thereby achieving a carbon-hydrogen balance in the coal-based chemical process, greatly improving the energy efficiency and carbon efficiency of the coal utilization process, and significantly reducing carbon emissions, thereby reducing carbon emissions at the source.

[0015] (2) The system and method for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen provided by the present invention solves the problem of "more carbon and less hydrogen" faced by the production of methanol from coal-based synthesis gas, realizes the green production and reliable supply of hydrogen and the recycling of carbon dioxide, achieves zero carbon emissions, and realizes the full utilization of coal resources and the efficient consumption and utilization of new energy electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a system for the coupling of coal gasification with low-carbon hydrogen and green hydrogen to produce methanol and ammonia according to the present invention; Figure numerals: 1-Texaco coal gasifier, 2-desulfurization tower, 3-first pressure swing adsorption tower, 4-carbon dioxide electrolysis cell, 5-second pressure swing adsorption tower, 6-water electrolysis cell, 7-air separation unit, 8-first gas ratio adjustment device, 9-methanol synthesis tower, 10-second gas ratio adjustment device, 11-ammonia synthesis tower. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below through specific embodiments in combination with the accompanying drawings, but the implementation mode of the present invention is not limited thereto.

[0018] Example 1 Please refer to the attached Figure 1 A system for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen is shown, including a coal gasification unit, a carbon dioxide electrolysis unit, a low-carbon hydrogen production unit, a green hydrogen production unit, an air separation unit, a methanol preparation unit, and an ammonia preparation unit.

[0019] Specifically, the coal gasification unit is used for gasification reaction of water-coal slurry, oxygen and water vapor to generate crude synthesis gas, and desulfurizes and removes carbon dioxide from the crude synthesis gas to obtain refined synthesis gas; the coal gasification unit includes a Texaco coal gasification furnace, a desulfurization tower, and a first pressure swing adsorption tower which are arranged in sequence.

[0020] Specifically, the carbon dioxide electrolysis unit is used for electrolyzing carbon dioxide and water to generate electrolytic synthesis gas and oxygen, and the carbon dioxide electrolysis unit comprises a carbon dioxide electrolysis cell.

[0021] Specifically, the low-carbon hydrogen production unit is used to separate the tail gas from hydrogen production by cracking methanol by pressure swing adsorption to obtain hydrogen and carbon dioxide; the low-carbon hydrogen production unit includes a second pressure swing adsorption tower.

[0022] Specifically, the green hydrogen production unit is used to electrolyze water to generate oxygen and hydrogen; the green hydrogen production unit includes a water electrolysis cell.

[0023] Specifically, the air separation unit is used to separate air into oxygen and nitrogen; the air separation unit includes an air separation device.

[0024] Specifically, the methanol preparation unit is used to produce methanol after adjusting the synthesis gas to a suitable carbon-hydrogen ratio; the methanol preparation unit includes a first gas ratio adjustment device and a methanol synthesis tower which are arranged in sequence.

[0025] Specifically, the ammonia preparation unit is used to produce ammonia after adjusting nitrogen and hydrogen to a suitable carbon-hydrogen ratio; the ammonia preparation unit includes a second gas ratio adjustment device and an ammonia synthesis tower which are arranged in sequence.

[0026] Specifically, the oxygen outlet of the water electrolysis cell, the oxygen outlet of the air separation unit, and the oxygen outlet of the carbon dioxide electrolysis cell are all connected to the oxygen inlet of the Texaco coal gasifier, the carbon dioxide outlet of the first pressure swing adsorption tower and the carbon dioxide outlet of the second pressure swing adsorption tower are all connected to the carbon dioxide inlet of the carbon dioxide electrolysis cell, the hydrogen outlet of the water electrolysis cell and the hydrogen outlet of the second pressure swing adsorption tower are connected to the first gas ratio regulation device and the second gas ratio regulation device after being connected in parallel, the synthesis gas outlet of the first pressure swing adsorption tower and the electrolysis synthesis gas outlet of the carbon dioxide electrolysis cell are connected to the first gas ratio regulation device after being connected in parallel, and the nitrogen outlet of the air separation unit is connected to the second gas ratio regulation device.

[0027] Example 2 A method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, using the system for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen of Example 1, specifically comprising: (1) The tail gas from methanol cracking to produce hydrogen is sent to the second pressure swing adsorption tower to separate hydrogen and carbon dioxide. At the same time, the electricity generated by wind power and solar power generation is supplied to the carbon dioxide electrolysis cell, the water electrolysis cell, and the air separation unit. External water and the carbon dioxide separated from the second pressure swing adsorption tower are sent to the carbon dioxide electrolysis cell for electrolysis to generate electrolytic synthesis gas and oxygen. External water is sent to the water electrolysis cell for electrolysis to generate hydrogen and oxygen. Air is sent to the air separation unit to separate oxygen and nitrogen. (2) The water-coal slurry and water vapor are fed into the Texaco coal gasifier, and the oxygen generated by the water electrolysis cell, the air separation unit, and the carbon dioxide electrolysis cell is fed into the Texaco coal gasifier to generate a crude synthesis gas. The crude synthesis gas is passed through a desulfurization tower to remove hydrogen sulfide, and then passed through a first pressure swing adsorption tower to separate carbon dioxide to obtain a refined synthesis gas; (3) The carbon dioxide separated from the first pressure swing adsorption tower is fed into the carbon dioxide electrolysis cell, and the refined synthesis gas separated from the first pressure swing adsorption tower is electrolyzed with the carbon dioxide electrolysis cell to generate electrolytic synthesis gas, which is fed into the first gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated from the second pressure swing adsorption tower are fed into the first gas ratio adjustment device. The first gas ratio adjustment device adjusts the carbon-hydrogen ratio to obtain the synthesis gas with a suitable carbon-hydrogen ratio, and then feeds it into the methanol synthesis tower for methanol production. (4) The nitrogen separated by the air separation unit is sent to the second gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated by the second pressure swing adsorption tower are sent to the second gas ratio adjustment device. The second gas ratio adjustment device adjusts the nitrogen-hydrogen ratio to obtain a mixed gas with a suitable nitrogen-hydrogen ratio and then sends it to the ammonia synthesis tower for ammonia production.

[0028] In this embodiment, the tail gas from methanol cracking to produce hydrogen contains carbon dioxide (68%), hydrogen (24%) and other impurity gases.

[0029] In this embodiment, the crude synthesis gas contains carbon monoxide, hydrogen, carbon dioxide, and hydrogen sulfide, and the desulfurizer used in the desulfurization tower is iron oxide. The iron oxide desulfurizer has the ability to selectively remove hydrogen sulfide. Its desulfurization principle is to chemically adsorb hydrogen sulfide into the small pores of the desulfurizer. When the desulfurizer reaches saturation, its desulfurization ability can be restored by regeneration treatment (such as steam stripping). The iron oxide desulfurizer is not only suitable for high temperature environments, but also for medium and low temperature environments.

[0030] Pressure swing adsorption (PSA) is a new type of gas adsorption separation technology. It is a reversible physical adsorption process that works between two pressure states based on the physical adsorption of gas molecules on the internal surface of a porous solid substance (adsorbent). In this embodiment, the number of the first pressure swing adsorption towers is 3, and the number of the second pressure swing adsorption towers is 5.

[0031] Solid oxide electrolysis cell (SOEC) can use solid oxide as electrolyte to electrolyze water or other compounds under high temperature and applied voltage, thereby realizing the conversion of electrical energy and thermal energy into chemical energy. In this embodiment, both the water electrolysis cell and the carbon dioxide electrolysis cell adopt solid oxide electrolysis cell. Among them, the cathode material of the water electrolysis cell adopts Ni-YSZ metal ceramic composite material, and the anode material adopts strontium-doped lanthanum gallate, with an operating temperature of 600°C and an operating voltage of 1.3V. Ni-YSZ composite material has good electrical conductivity, catalytic activity, chemical stability and thermal shock resistance, and effectively catalyzes the oxidation reaction of fuel, thereby releasing electrons and ions. The cathode material of the carbon dioxide electrolysis cell adopts vanadium-doped lanthanum strontium iron composite gadolinium-doped cerium oxide, and the anode material adopts iridium oxide, with an operating temperature of 800°C and an operating voltage of 1.5V. The composite material formed by vanadium-doped lanthanum strontium iron (LSFVx) and gadolinium-doped cerium oxide (GDC) combines the advantages of both materials. Gadolinium-doped cerium oxide (GDC) has high electrical conductivity and stability. Vanadium doping can increase the cathode oxygen vacancy concentration, improve the cathode's high-temperature adsorption activation ability and electrocatalytic reduction performance for carbon dioxide, and iridium oxide has good electrical conductivity and chemical stability as well as good antioxidant and electrocatalytic properties. It can stably exist in high temperature and oxidative environments and effectively promote the generation of oxygen.

[0032] In this embodiment, the first gas ratio adjustment device adjusts the molar ratio of CO to H2 to 0.465-0.485, and the second gas ratio adjustment device adjusts the molar ratio of N2 to H2 to 0.355-0.455.

[0033] The methanol synthesis tower and the ammonia synthesis tower can directly utilize existing equipment to realize the production of methanol and ammonia.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the technical solution and conceptual invention of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, characterized in that: include: The coal gasification unit is used for gasification reaction of water-coal slurry, oxygen and water vapor to generate crude synthesis gas, and desulfurize and remove carbon dioxide from the crude synthesis gas to obtain refined synthesis gas; Carbon dioxide electrolysis unit, used for electrolysis of carbon dioxide and water to generate electrolytic synthesis gas and oxygen, Low-carbon hydrogen production unit, used to separate the tail gas from methanol cracking and hydrogen production by pressure swing adsorption to obtain hydrogen and carbon dioxide; Green hydrogen production unit, used to electrolyze water to produce oxygen and hydrogen; Air separation unit, used to separate air into oxygen and nitrogen; Methanol preparation unit, used to produce methanol after adjusting the synthesis gas to a suitable carbon-hydrogen ratio; An ammonia preparation unit, used to produce ammonia after adjusting nitrogen and hydrogen to a suitable carbon-hydrogen ratio; The oxygen generated by the green hydrogen production unit, the oxygen generated by the air separation unit, and the oxygen generated by the carbon dioxide electrolysis unit are all fed into the coal gasification unit, the carbon dioxide separated by the low-carbon hydrogen production unit and the carbon dioxide removed from the coal gasification unit are all fed into the carbon dioxide electrolysis unit, the hydrogen generated by the green hydrogen production unit and the hydrogen generated by the low-carbon hydrogen production unit are connected and fed into the methanol preparation unit and the ammonia preparation unit respectively, the refined synthesis gas obtained by the coal gasification unit and the electrolytic synthesis gas obtained by the carbon dioxide electrolysis unit are connected and fed into the methanol preparation unit, and the nitrogen obtained by the air separation unit is fed into the ammonia preparation unit.

2. A system for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The coal gasification unit comprises a Texaco coal gasification furnace, a desulfurization tower, and a first pressure swing adsorption tower which are arranged in sequence; the carbon dioxide electrolysis unit comprises a carbon dioxide electrolysis cell; the low-carbon hydrogen production unit comprises a second pressure swing adsorption tower; the green hydrogen production unit comprises a water electrolysis cell; the air separation unit comprises an air separation unit; the methanol preparation unit comprises a first gas ratio adjustment device and a methanol synthesis tower which are arranged in sequence; the ammonia preparation unit comprises a second gas ratio adjustment device and an ammonia synthesis tower which are arranged in sequence; the oxygen outlet of the water electrolysis cell, the oxygen outlet of the air separation unit, the carbon dioxide The oxygen outlets of the electrolytic cells are connected to the oxygen inlet of the Texaco coal gasifier, the carbon dioxide outlets of the first pressure swing adsorption tower and the carbon dioxide outlets of the second pressure swing adsorption tower are connected to the carbon dioxide inlet of the carbon dioxide electrolytic cell, the hydrogen outlets of the water electrolytic cell and the hydrogen outlets of the second pressure swing adsorption tower are connected in parallel to the first gas ratio regulating device and the second gas ratio regulating device respectively, the synthesis gas outlet of the first pressure swing adsorption tower and the electrolysis synthesis gas outlet of the carbon dioxide electrolytic cell are connected in parallel to the first gas ratio regulating device, and the nitrogen outlet of the air separation unit is connected to the second gas ratio regulating device.

3. A method for the co-production of methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen, characterized in that: The system of claim 2 is used to co-produce methanol and ammonia, comprising: (1) The tail gas from methanol cracking to produce hydrogen is sent to the second pressure swing adsorption tower to separate hydrogen and carbon dioxide. At the same time, the electricity generated by wind power and solar power generation is supplied to the carbon dioxide electrolysis cell, the water electrolysis cell, and the air separation unit. External water and the carbon dioxide separated from the second pressure swing adsorption tower are sent to the carbon dioxide electrolysis cell for electrolysis to generate electrolytic synthesis gas and oxygen. External water is sent to the water electrolysis cell for electrolysis to generate hydrogen and oxygen. Air is sent to the air separation unit to separate oxygen and nitrogen. (2) The water-coal slurry and water vapor are fed into the Texaco coal gasifier, and the oxygen generated by the water electrolysis cell, the air separation unit, and the carbon dioxide electrolysis cell is fed into the Texaco coal gasifier to generate a crude synthesis gas. The crude synthesis gas is passed through a desulfurization tower to remove hydrogen sulfide, and then passed through a first pressure swing adsorption tower to separate carbon dioxide to obtain a refined synthesis gas; (3) The carbon dioxide separated from the first pressure swing adsorption tower is fed into the carbon dioxide electrolysis cell, and the refined synthesis gas separated from the first pressure swing adsorption tower is electrolyzed with the carbon dioxide electrolysis cell to generate electrolytic synthesis gas, which is fed into the first gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated from the second pressure swing adsorption tower are fed into the first gas ratio adjustment device. The first gas ratio adjustment device adjusts the carbon-hydrogen ratio to obtain the synthesis gas with a suitable carbon-hydrogen ratio, and then feeds it into the methanol synthesis tower for methanol production. (4) The nitrogen separated by the air separation unit is sent to the second gas ratio adjustment device. At the same time, the hydrogen generated by electrolysis in the water electrolysis cell and the hydrogen separated by the second pressure swing adsorption tower are sent to the second gas ratio adjustment device. The second gas ratio adjustment device adjusts the nitrogen-hydrogen ratio to obtain a mixed gas with a suitable nitrogen-hydrogen ratio and then sends it to the ammonia synthesis tower for ammonia production.

4. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The water electrolysis cell adopts a solid oxide electrolysis cell, the cathode material adopts a Ni-YSZ metal ceramic composite material, the anode material adopts strontium-doped lanthanum gallate, the working temperature is 600° C., and the working voltage is 1.3V.

5. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The carbon dioxide electrolysis cell adopts a solid oxide electrolysis cell, the cathode material adopts vanadium-doped lanthanum strontium iron composite gadolinium-doped cerium oxide, the anode material adopts iridium oxide, the working temperature is 800° C., and the working voltage is 1.5V.

6. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The desulfurizing agent used in the desulfurizing tower is iron oxide.

7. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The number of the first pressure swing adsorption towers is 3, and the number of the second pressure swing adsorption towers is 5.

8. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The first gas ratio adjusting device adjusts the molar ratio of CO to H2 to 0.465-0.

485.

9. The method for co-producing methanol and ammonia by coupling coal gasification with low-carbon hydrogen and green hydrogen according to claim 1, characterized in that: The second gas ratio adjusting device adjusts the molar ratio of N2 to H2 to be 0.355-0.455.

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