System and method for co-producing green sodium carbonate and ammonium chloride by using renewable energy sources

Abstract

A system and method for co-producing green sodium carbonate and ammonium chloride by using renewable energy sources. The system comprises a renewable energy source power generation subsystem, a water electrolysis subsystem, an air separation subsystem, an ammonia synthesis subsystem, a tail-gas pretreatment subsystem, a waste-salt pretreatment subsystem and a sodium carbonate synthesis subsystem. By utilizing renewable wind and solar energy to generate electricity for electrolytic hydrogen production and air separation, the impact of renewable energy power generation on a power grid and the difficulty in balancing the fluctuating power supply of the power grid are solved, on-site consumption of green power is achieved, the green power is converted on site into green products with economic value added, and stable operation of a green electricity–green hydrogen–green chemical production line is achieved; and industrial waste salts and the industrial emissions of carbon dioxide tail gas are used as green raw materials for sodium carbonate, and are integrated with carbon tail gas and industrial waste salts discharged by industrial enterprises in the vicinity, and resource utilization of waste is conducted, thereby reducing carbon emissions and also realizing a green circular economy.

Description

A system and method for co-producing green soda ash and ammonium chloride using renewable energy Technical Field

[0001] The present invention relates to the technical field of renewable energy, and in particular to a system and method for co-producing green soda ash and ammonium chloride with renewable energy. Background Art

[0002] As the world's population grows and economies develop, the resulting environmental problems are becoming increasingly prominent. Climate change is a global issue facing humanity today. As carbon dioxide emissions surge, greenhouse gases pose a threat to life. Large-scale development and utilization of renewable energy is an effective way to reduce carbon dioxide emissions and energy shortages.

[0003] However, it's worth noting that the primary sources of renewable energy generation include wind and photovoltaic power, and the development of renewable electricity is highly dependent on electricity load. Furthermore, large-scale ultra-high voltage transmission is costly, and the intermittent and unstable nature of photovoltaic and wind power generation places pressure on both the transmitting and receiving power grids. This has led to a significant inverse distribution between my country's renewable energy resources and electricity demand, creating challenges in delivering green electricity to remote areas rich in renewable energy.

[0004] The combination of new energy power generation and electrochemistry has become a research hotspot. By converting green electricity into chemical products and realizing the storage and transportation of chemicals for power storage and transmission, it can not only expand the space for the consumption of green electricity, but also significantly reduce the cost of power storage and transmission, creating favorable conditions for the development of high-quality renewable energy in remote areas. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention discloses a system and method for the co-production of green soda ash and ammonium chloride using renewable energy. By adopting a circular economy solution that combines green hydrogen-green ammonia with waste gas-waste solids, and through the optimized configuration and coupled integration of various devices, it not only effectively solves the impact of the intermittent and volatile nature of new energy power generation on the stable operation of chemical plants, but also achieves the stable on-site consumption of wind and solar power generation; it also achieves the goal of carbon reduction and emission reduction through the resource utilization of carbon dioxide gas and industrial waste salt, turning waste into treasure by nature and obtaining better economic benefits.

[0006] In order to achieve the above technical objectives, the present invention provides a system for co-producing green soda ash and ammonium chloride using renewable energy, the system comprising:

[0007] Renewable energy generation subsystem for generating green electricity using wind and / or solar energy;

[0008] A water electrolysis subsystem, connected to the renewable energy generation subsystem, for using the green electricity to electrolyze water to produce hydrogen and oxygen;

[0009] an air separation subsystem, the air separation subsystem being connected to the renewable energy power generation subsystem and configured to use the green electricity to separate air to obtain nitrogen;

[0010] An ammonia synthesis subsystem, which is connected to the hydrogen output end of the water electrolysis subsystem and the nitrogen output end of the air separation subsystem via pipelines, and is used to synthesize green ammonia using the hydrogen obtained from the water electrolysis subsystem and the nitrogen obtained from the air separation subsystem;

[0011] Tail gas pretreatment subsystem: used to concentrate carbon dioxide in industrial tail gas to obtain raw tail gas;

[0012] Waste salt pretreatment subsystem: used to remove impurities and purify industrial waste salt to obtain raw waste salt;

[0013] Soda ash synthesis subsystem: The soda ash synthesis subsystem is connected to the green ammonia output end of the synthetic ammonia subsystem, the raw tail gas output end of the tail gas pretreatment subsystem, and the raw waste salt output end of the waste salt pretreatment subsystem through pipelines, and is used to prepare green soda ash using the green ammonia, raw tail gas and raw waste salt as raw materials and produce ammonium chloride as a by-product.

[0014] In the above technical solution, waste salt (mainly composed of sodium chloride) produced by chemical plants is utilized, and the carbon dioxide exhaust gas produced by the chemical plants is collected. After purification through a carbon dioxide purification device, the raw exhaust gas is sent to the green soda ash unit. At the same time, wind power / photovoltaic power is combined to generate green electricity for electrolysis of pure water to produce hydrogen, and green electricity is used as the energy source for the air separation unit to produce nitrogen; by feeding hydrogen / nitrogen into the ammonia synthesis system according to the feed ratio required for ammonia synthesis, the prepared green ammonia is also used as the raw material for the green soda ash unit. In the soda ash synthesis subsystem, the treated raw waste salt, raw exhaust gas and ammonia are used as raw materials to obtain green soda ash products and ammonium chloride by-products that meet the purity standards, thus forming a process route with green electricity-green hydrogen-green ammonia-green soda ash as the main line.

[0015] The above-mentioned technical solution uses renewable green electricity to produce green hydrogen. Compared with coal-to-hydrogen production, it not only eliminates carbon emission process links such as coal gasification and conversion, but the by-product high-purity oxygen can also be used for the oxygen needs of surrounding steelmaking, chemical and other enterprises, reducing the energy consumption of traditional air separation oxygen production; at the same time, the carbon dioxide tail gas emitted by surrounding power plants, steelmaking or chemical equipment can be utilized as a resource; if the surrounding industrial waste salt resources are sufficient, a fully circular economy can be achieved to prepare green soda ash and ammonium chloride products, promoting the chemical industry to achieve zero-carbon transformation and upgrading.

[0016] The above-mentioned technical solution fully combines renewable energy power generation with green hydrogen, green ammonia and green soda ash, converts green electricity into basic chemical products with stable chemical properties, and transforms electricity storage and transmission into chemical storage and transportation. It can expand the space for green electricity consumption while greatly reducing the cost of electricity storage and transmission, creating favorable conditions for the development of high-quality renewable energy in remote areas.

[0017] In a further example of the present invention, the water electrolysis subsystem includes an electrolytic cell for electrolyzing water, a hydrogen purification device connected to the crude hydrogen output of the electrolytic cell, and an oxygen purification device connected to the crude oxygen output of the electrolytic cell. Furthermore, the water electrolysis subsystem also includes a hydrogen storage device.

[0018] In a further example of the present invention, the tail gas pretreatment subsystem includes a carbon dioxide absorption and desorption module, and the desorption module outputs the raw tail gas.

[0019] In a further example of the present invention, the concentration of carbon dioxide in the raw tail gas is ≥80 wt %.

[0020] In a further example of the present invention, the waste salt pretreatment subsystem includes a salt washing module and / or a fractionation and crystallization module.

[0021] In a further example of the present invention, the raw waste salt satisfies that the sodium chloride content of the dry salt is ≥98.5%.

[0022] In a further example of the present invention, the soda ash synthesis subsystem includes a heavy alkali module and an ammonium chloride module, wherein the heavy alkali module is used to prepare heavy alkali using green ammonia, raw material tail gas and raw material waste salt as raw materials and filter out ammonium chloride mother liquor, and the heavy alkali is heated to obtain a soda ash product; the filtrate output end of the heavy alkali module is connected to the raw material input end of the ammonium chloride module; the ammonium chloride module is used to generate the ammonium chloride product by low-temperature crystallization, and the crystal slurry output end of the ammonium chloride module is connected to the raw material input end of the heavy alkali module.

[0023] In a further example of the present invention, the renewable energy generation subsystem includes a wind power / photovoltaic power generation device and an energy storage device.

[0024] On the other hand, the present application proposes a method for co-producing green soda ash and ammonium chloride using renewable energy, the method comprising the following steps:

[0025] S1, using wind and / or solar power to generate green electricity;

[0026] S2, using the green electricity to electrolyze water to obtain hydrogen and oxygen; using the green electricity to separate air to obtain nitrogen;

[0027] S3, synthesizing green ammonia using the hydrogen and nitrogen obtained in step S2; concentrating the concentration of carbon dioxide in the industrial tail gas to ≥80% to obtain raw tail gas; pretreating the industrial waste salt to a sodium chloride content of ≥98.5% in the dry salt to obtain raw waste salt;

[0028] S4, using the green ammonia, raw material tail gas and raw material waste salt as raw materials to obtain green soda ash and produce ammonium chloride as a by-product.

[0029] Compared with the existing technology, the beneficial effects of the present invention are: by utilizing renewable energy wind and solar power generation for electrolytic hydrogen production and air separation, the impact of renewable energy power generation on the power grid and the difficulty of the power grid in achieving fluctuating power supply balance are solved, the on-site consumption of green electricity is realized, and green electricity is converted on-site into green products with economic added value, thereby achieving the smooth operation of the green electricity-green hydrogen-green chemical production line; industrial waste salt and industrial exhaust carbon dioxide are used as green soda ash raw materials, and the carbon exhaust gas and industrial waste salt of surrounding industrial enterprises are integrated to carry out resource utilization of waste, reduce carbon emissions and realize a green circular economy at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0031] FIG1 shows a structural diagram of a system for co-producing green soda ash and ammonium chloride using renewable energy according to the present invention.

[0032] Among them, the above-mentioned drawings include the following figure marks: 1-renewable energy generation subsystem, 11-energy storage device, 2-water electrolysis subsystem, 21-hydrogen purification device, 22-oxygen purification device, 23-hydrogen storage device, 3-air separation subsystem, 4-synthetic ammonia subsystem, 5-tail gas pretreatment subsystem, 6-waste salt pretreatment subsystem, 7-soda ash synthesis subsystem. DETAILED DESCRIPTION

[0033] To facilitate understanding of the present invention, the present invention will be described in more detail below, with preferred embodiments of the present invention provided. However, it should be understood that these embodiments are merely for the purpose of further explanation and are not to be construed as limiting the present invention in any form, i.e., they are not intended to limit the scope of protection of the present invention.

[0034] Example 1

[0035] A system for co-producing green soda ash and ammonium chloride using renewable energy, as shown in FIG1 , comprises:

[0036] (1) Renewable energy generation subsystem 1, for generating green electricity using wind and / or solar energy. The renewable energy generation subsystem 1 of the present invention includes a solar power generation system and a wind power generation system, and is primarily used to convert solar and / or wind energy into electrical energy. The green electricity generated by the renewable energy generation subsystem 1 will primarily be used to meet the electricity needs of the water electrolysis subsystem 2 and the air separation subsystem 3, as well as the electricity needs of other chemical equipment.

[0037] Optionally, the renewable energy generation subsystem 1 includes a wind power / photovoltaic power generation device and an energy storage device 11. In actual operation, the energy storage device 11 can be used to overcome the intermittent and fluctuating nature of wind and solar power generation due to weather and climate, thereby ensuring stable and continuous operation of the overall process system.

[0038] Further optionally, the energy storage device 11 is a battery energy storage device 11, and its supporting scale theoretical basis is as follows:

[0039] The charging and discharging logic of the energy storage device 11: for the completely off-grid chemical product model and the green electricity hydrogen production combined with grid electricity for chemical equipment model: 1) Green electricity is used first for hydrogen production and downstream chemical equipment; 2) When green electricity is greater than the maximum demand of hydrogen production and chemical equipment, start charging the energy storage device 11; 3) When green electricity is greater than the maximum demand of hydrogen production, chemical equipment, and energy storage device 11, abandon electricity; 4) When green electricity is less than the maximum demand of hydrogen production and chemical equipment, start reducing the load of the chemical equipment; 5) When green electricity is less than the minimum operating load requirement of the chemical equipment, the energy storage device 11 discharges; 6) When the total amount of green electricity and energy storage device 11 is less than the minimum operating load requirement of the chemical equipment, the chemical equipment is shut down.

[0040] It should be noted that the present invention does not limit the specific structure of the energy storage device 11. Persons skilled in the art may, through non-inventive effort, select a suitable energy storage device and configure a suitable connection method, and the resulting technical solutions are all within the scope of protection of the present invention. Optionally, the energy storage device 11 includes multiple groups of energy storage units; these multiple groups of energy storage units are connected in parallel. Furthermore, optionally, the AC sides of the AC / DC bidirectional inverters within each energy storage unit are connected in parallel.

[0041] (2) A water electrolysis subsystem 2, which is connected to the renewable energy generation subsystem 1 and is used to electrolyze water using the green electricity to obtain hydrogen and oxygen.

[0042] It should be noted that the present invention does not limit the specific equipment and process for producing hydrogen by electrolysis of water, and those skilled in the art can select suitable equipment and process for producing hydrogen by electrolysis of water through non-creative labor. With the advancement of hydrogen energy-related research, the electrolysis of water to produce hydrogen has developed the following two different process routes: alkali solution method and proton exchange membrane method (PEM). Optionally, in the present embodiment, alkaline electrolyzer electrolysis produces hydrogen, and the alkaline electrolyzer hydrogen production system adopts a unit assembly structure, which is mainly composed of an electrolyzer, a gas-liquid processor (frame), a water pump, a water alkali tank, a control cabinet, a rectifier cabinet, a rectifier transformer, a flame arrester and the like; Optionally, the operating temperature of the alkali washing electrolyzer is 85-95°C, the operating pressure is 1.6-1.8MPaG, and the hydrogen product pressure at the outlet of the electrolyzer is approximately 1.4-1.6MPaG.

[0043] Optionally, the alkaline electrolyzers can be arranged in groups of 4-5, with each electrolyzer operating at a lower load limit of approximately 25%-30%. The electrolyzers are grouped and controlled during operation. This makes the entire system more flexible than chemical plants, with more flexible startup and shutdown. The operation and startup of the electrolyzers can be flexibly adjusted based on the green electricity load, allowing the green electricity generated by wind power to produce green hydrogen, which can serve as a hydrogen source for downstream green ammonia plants.

[0044] Optionally, the water electrolysis subsystem 2 includes an electrolytic cell for electrolyzing water, a hydrogen purification device 21 connected to a crude hydrogen output end of the electrolytic cell, and an oxygen purification device 22 connected to a crude oxygen output end of the electrolytic cell.

[0045] It should be noted that the oxygen and surplus hydrogen generated by the water electrolysis subsystem 2 during water electrolysis can be sold as products.

[0046] Optionally, the water electrolysis subsystem 2 further includes a hydrogen storage device 23, which stores part of the hydrogen obtained by electrolysis in the water electrolysis subsystem 2 in a hydrogen storage tank, and releases hydrogen when wind / solar power generation is insufficient to ensure the hydrogen demand of downstream chemical equipment.

[0047] It should be noted that the hydrogen storage device 23 can optionally use high-pressure gaseous hydrogen storage. The scale of the hydrogen storage device 23 is matched and calculated according to the load curve of local wind and solar power generation to ensure that when the output of renewable energy power is small, the chemical plant can operate at a reasonable load while achieving non-stop steady-state operation, thereby improving the operating reliability and stability of the device and achieving safe operation and economic benefits of the device.

[0048] (3) Air separation subsystem 3, which uses the green electricity to separate air to produce nitrogen. The produced nitrogen will be transported to the subsequent ammonia synthesis subsystem. It should be noted that in actual operation, the operating range of air separation subsystem 3 can be considered to be relatively large to accommodate fluctuations in the capacity of upstream and downstream systems.

[0049] (4) Ammonia synthesis subsystem 4, which is connected to the hydrogen output end of the water electrolysis subsystem 2 and the nitrogen output end of the air separation subsystem 3 through pipelines, and is used to synthesize green ammonia using the hydrogen obtained from the water electrolysis subsystem 2 and the nitrogen obtained from the air separation subsystem 3.

[0050] It should be noted that the present invention does not limit the specific equipment and process of the ammonia synthesis subsystem 4. A dynamic ammonia synthesis process can be optionally adopted. Those skilled in the art can select a suitable ammonia synthesis process and equipment through non-creative work, and the technical solutions thus formed are all within the scope of protection of the present invention.

[0051] (5) Tail gas pretreatment subsystem 5 is used to concentrate carbon dioxide in industrial tail gas to obtain raw tail gas.

[0052] Optionally, the tail gas pretreatment subsystem 5 includes a carbon dioxide absorption and desorption module, with the desorption module outputting raw tail gas. The tail gas pretreatment subsystem 5 uses a solvent method to purify carbon dioxide tail gas from surrounding factories, such as flue gas from power plants and steel mills, to obtain raw tail gas containing high concentrations of CO2, which is used as raw material for subsequent soda ash synthesis.

[0053] Optionally, the concentration of carbon dioxide in the raw tail gas is ≥80wt%. In the actual process, if the tail gas input into the tail gas pretreatment subsystem 5 is high-concentration tail gas from a coal chemical plant, it can be directly sent to the soda ash plant as raw material; if it is low-concentration carbon dioxide tail gas from a refinery or power plant, it can be concentrated to a purity of ≥80wt% and then supplied as soda ash raw material.

[0054] It should be noted that one stream of the raw tail gas can be fed into a carbon dioxide refining device for refining to obtain a food-grade CO2 liquid product for sale.

[0055] (6) Waste salt pretreatment subsystem 6, removes impurities and purifies industrial waste salt to obtain raw waste salt.

[0056] Optionally, the waste salt pretreatment subsystem 6 includes a salt washing module and / or a fractionation and crystallization module. In the actual process flow, if the separated industrial waste salt from surrounding enterprises meets the index requirements, it can be directly used as a raw material for soda ash synthesis; if the industrial waste salt does not meet the green soda ash feed requirements, it needs to be refined by the salt washing module to obtain the raw waste salt that meets the soda ash synthesis requirements; if the industrial waste salt has not been separated and purified, it needs to be separated by fractionation and crystallization in this solution before being used as a raw material for soda ash synthesis; if industrial waste salt is used as a blending raw material for industrial refined salt, the purity requirement index of the industrial waste salt will be determined based on its blending ratio, or it will be pretreated by operations such as salt washing or fractionation and crystallization.

[0057] It should be noted that when industrial waste salt is used directly as the raw material for green soda ash, its purity composition must meet the indicators of "industrial dry salt grade 1" or "industrial wet salt grade 1" for refined industrial salt in "Industrial Salt" (GB / T 5462-2015) and can be directly used as feed.

[0058] Optionally, the raw waste salt satisfies the requirement that the sodium chloride content of the dry salt is ≥98.5%.

[0059] (7) Soda ash synthesis subsystem 7, which is connected to the green ammonia output end of the synthetic ammonia subsystem 4, the raw tail gas output end of the tail gas pretreatment subsystem 5 and the raw waste salt output end of the waste salt pretreatment subsystem 6 through pipelines, and is used to prepare green soda ash using the green ammonia, raw tail gas and raw waste salt as raw materials and produce ammonium chloride as a by-product.

[0060] Optionally, the soda ash synthesis subsystem 7 includes a heavy alkali module and an ammonium chloride module, wherein the heavy alkali module is used to prepare heavy alkali using green ammonia, raw material tail gas and raw material waste salt as raw materials and filter out ammonium chloride mother liquor, and the heavy alkali is heated to obtain a soda ash product; the filtrate output end of the heavy alkali module is connected to the raw material input end of the ammonium chloride module, and in the actual process, the ammonium chloride mother liquor filtered out by the heavy alkali module is used as the raw material input of the ammonium chloride module after absorbing ammonia; the ammonium chloride module is used for low-temperature crystallization to obtain an ammonium chloride mixed crystal slurry containing an ammonium chloride product, and the mixed crystal slurry is centrifuged to obtain an ammonium chloride product and a crystal slurry; the crystal slurry output end of the ammonium chloride module is connected to the raw material input end of the heavy alkali module, and in the actual process, the crystal slurry output by the ammonium chloride module is used as the input material of the heavy alkali module to absorb ammonia and carbonize.

[0061] It should be noted that the present invention does not limit the soda ash synthesis process and equipment used. The concentrated gas alkali production process (secondary ammonia absorption and primary carbonization) and the cold process for producing ammonium chloride can be selected to produce soda ash and produce ammonium chloride as a by-product.

[0062] In addition to the above-mentioned subsystems, the renewable energy co-production system of green soda ash and ammonium chloride of the present invention also includes auxiliary facilities for power conversion and distribution, including substations, cabinet rooms and rectifier rooms, as well as public engineering facilities such as air compressor stations, pure water stations and cooling circulation water stations.

[0063] The present invention utilizes renewable energy sources such as wind and solar power generation for electrolytic hydrogen production, and compensates for the intermittent and fluctuating nature of wind and solar power generation through energy storage and hydrogen storage facilities, while achieving stable operation of the downstream synthetic ammonia production process. It utilizes carbon dioxide tail gas from various surrounding industrial enterprises and industrial waste salt resources from coal chemical enterprises to prepare green soda ash and produce ammonium chloride as a by-product.

[0064] Example 2

[0065] Based on the system for co-producing green soda ash and ammonium chloride with renewable energy shown in Example 1, this embodiment proposes a method for co-producing green soda ash and ammonium chloride with renewable energy, which includes the following steps:

[0066] S1, using wind and / or solar power to generate green electricity;

[0067] S2, using the green electricity to electrolyze water to obtain hydrogen and oxygen; using the green electricity to separate air to obtain nitrogen;

[0068] S3, synthesizing green ammonia using the hydrogen and nitrogen obtained in step S2; concentrating the concentration of carbon dioxide in the industrial tail gas to ≥80% to obtain raw tail gas; pretreating the industrial waste salt to a sodium chloride content of ≥98.5% in the dry salt to obtain raw waste salt;

[0069] S4, using the green ammonia, raw material tail gas and raw material waste salt as raw materials to obtain green soda ash and produce ammonium chloride as a by-product.

[0070] Example 3

[0071] This example demonstrates a process flow for co-producing green soda ash and ammonium chloride from renewable energy using the technical solution shown in Example 2 under specific working conditions. It should be noted that this process flow is only a demonstration of a preferred process and does not limit the scope of protection of the present invention.

[0072] A method for co-producing green soda ash and ammonium chloride with renewable energy. In this embodiment, the renewable energy generation subsystem 1 takes an isolated grid operation device with a wind power installed capacity of 400MW and a solar power installed capacity of 100MW as an example. Based on the local typical comprehensive power output curve, the electrolysis water subsystem 2 is configured with a normal green hydrogen production of 35,000Nm 3 / h; Specifically, the hydrogen production of a single unit is 1200Nm 3 45 alkaline water electrolyzers with a capacity of 14,000 Nm / h (30 of which are used to produce green ammonia and 15 are used to produce hydrogen for hydrogen storage equipment); 3 air separation subsystems with a capacity of 14,000 Nm / h 3 / h nitrogen; the liquid ammonia output of the synthetic ammonia subsystem 4 is 140,000 tons / year; the production capacity of the soda ash synthesis subsystem 7 is 420,000 tons / year, of which the industrial waste salt raw material consumption is 480,000 tons / year and the carbon dioxide consumption is 266,000 tons / year.

[0073] The carbon emission accounting for the 420,000 tons / year soda ash plant in this embodiment is shown in Table 1.

[0074] Table 1

[0075] Table 1 demonstrates that the present invention utilizes local resources, such as air and water, to produce green ammonia using renewable energy sources such as solar and wind energy. This process also utilizes industrial waste salt and tail gas carbon dioxide to produce soda ash and ammonium chloride products. This achieves economic benefits while also achieving the goals of a green, low-carbon, and circular economy.

[0076] It should be noted that the above content is a further detailed description of the present invention in conjunction with specific implementation methods, and the specific implementation of the present invention cannot be considered to be limited to these descriptions; the dimensional data of this embodiment does not necessarily limit the technical solution, but only illustrates one specific working condition. For those skilled in the art of the present invention, simple improvements and modifications can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A system for co-producing green soda ash and ammonium chloride using renewable energy, characterized in that: include: A renewable energy power generation subsystem (1) for generating green electricity using wind energy and / or solar energy; A water electrolysis subsystem (2), the water electrolysis subsystem (2) being connected to the renewable energy generation subsystem (1) and configured to electrolyze water using the green electricity to generate hydrogen and oxygen; An air separation subsystem (3), the air separation subsystem (3) being connected to the renewable energy power generation subsystem (1) and configured to use the green electricity to separate air to obtain nitrogen; an ammonia synthesis subsystem (4), the ammonia synthesis subsystem (4) being connected to the hydrogen output end of the water electrolysis subsystem (2) and the nitrogen output end of the air separation subsystem (3) via pipelines, and being used to synthesize green ammonia using the hydrogen obtained from the water electrolysis subsystem (2) and the nitrogen obtained from the air separation subsystem (3); The tail gas pretreatment subsystem (5) is used to concentrate carbon dioxide in the industrial tail gas to obtain raw tail gas; The waste salt pretreatment subsystem (6) is used to remove impurities and purify industrial waste salt to obtain raw waste salt; A soda ash synthesis subsystem (7) is connected to the green ammonia output end of the ammonia synthesis subsystem (4), the raw tail gas output end of the tail gas pretreatment subsystem (5), and the raw waste salt output end of the waste salt pretreatment subsystem (6) via pipelines, and is used to prepare green soda ash using the green ammonia, raw tail gas, and raw waste salt as raw materials and produce ammonium chloride as a by-product.

2. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The water electrolysis subsystem (2) comprises an electrolytic cell for electrolyzing water, a hydrogen purification device (21) connected to a crude hydrogen output end of the electrolytic cell, and an oxygen purification device (22) connected to a crude oxygen output end of the electrolytic cell.

3. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The water electrolysis subsystem (2) further includes a hydrogen storage device (23).

4. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The tail gas pretreatment subsystem (5) comprises a carbon dioxide absorption and desorption module, and the desorption module outputs the raw tail gas.

5. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The concentration of carbon dioxide in the raw tail gas is ≥80wt%.

6. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The waste salt pretreatment subsystem (6) includes a salt washing module and / or a fractionation and crystallization module.

7. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The raw waste salt satisfies the requirement that the sodium chloride content of the dry salt is ≥98.5%.

8. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The soda ash synthesis subsystem (7) comprises a heavy alkali module and an ammonium chloride module, wherein the heavy alkali module is used to prepare heavy alkali using green ammonia, raw material tail gas and raw material waste salt as raw materials and filter out ammonium chloride mother liquor, and the heavy alkali is heated to obtain a soda ash product; the filtrate output end of the heavy alkali module is connected to the raw material input end of the ammonium chloride module; the ammonium chloride module is used to generate the ammonium chloride product by low-temperature crystallization, and the crystal slurry output end of the ammonium chloride module is connected to the raw material input end of the heavy alkali module.

9. The system for co-producing green soda ash and ammonium chloride from renewable energy according to claim 1, characterized in that: The renewable energy generation subsystem (1) comprises a wind power / photovoltaic power generation device and an energy storage device (11).

10. A method for co-producing green soda ash and ammonium chloride using renewable energy, characterized in that: The following steps are involved: S1, using wind and / or solar power to generate green electricity; S2, using the green electricity to electrolyze water to obtain hydrogen and oxygen; using the green electricity to separate air to obtain nitrogen; S3, synthesizing green ammonia using the hydrogen and nitrogen obtained in step S2; concentrating the concentration of carbon dioxide in the industrial tail gas to ≥80% to obtain raw tail gas; pretreating the industrial waste salt to a sodium chloride content of ≥98.5% in the dry salt to obtain raw waste salt; S4, using the green ammonia, raw material tail gas and raw material waste salt as raw materials to obtain green soda ash and produce ammonium chloride as a by-product.

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