System and method for peak shaving of thermal power by coupling high-temperature steam electrolysis with gypsum-based sulfur production

Abstract

The application discloses a thermal power peak shaving system and method for sulfur production by coupling high-temperature water vapor electrolysis with gypsum, relates to the technical field of thermal power peak shaving and power plant gypsum resource utilization, and comprises a thermal power generation module, a high-temperature water vapor electrolysis module, a hydrogen-oxygen combustion module and a hydrogen reduction gypsum sulfur production module; the thermal power generation module is used for thermal power generation and provides high-temperature water vapor for the high-temperature water vapor electrolysis module; the high-temperature water vapor electrolysis module is used for electrolyzing water vapor at high temperature to generate hydrogen and oxygen, and provides the hydrogen and oxygen for the hydrogen-oxygen combustion module, wherein the hydrogen is also provided for the hydrogen reduction gypsum sulfur production module and used as a reducing agent of gypsum; the hydrogen-oxygen combustion module is used for burning the hydrogen and oxygen to generate high-temperature water vapor; the application is different from the previous peak shaving mode in which electricity and heat are stored and then released for thermal power generation, but converts the abundant heat into high-value sulfur products, so that the thermal power peak shaving and the desulfurization gypsum resource utilization are realized.

Description

Technical Field

[0001] This invention relates to the fields of thermal power peak shaving and power plant gypsum resource utilization technology, specifically to a thermal power peak shaving system and method for producing sulfur from gypsum via high-temperature steam electrolysis coupling. Background Technology

[0002] Currently, the installed capacity of new energy sources such as wind power and photovoltaics is growing rapidly. Coal-fired power units are gradually transforming from primary power sources to basic, guaranteed, and flexible power sources. Deep peak shaving has become the core direction for the flexibility transformation of thermal power plants. The mainstream peak shaving technologies for thermal power plants currently include molten salt thermal storage, hot water tank thermal storage, electrode boilers, steam recompression heating, and high-temperature solid oxide electrolysis coupled with power plant peak shaving. Among these, molten salt thermal storage achieves thermoelectric decoupling by heating molten salt with extracted steam, while the high-temperature solid oxide electrolysis coupling scheme activates the electrolysis device for peak shaving when the grid load is below 40% of the boiler's rated load. In addition, some research has attempted to combine high-temperature steam electrolysis with hydrogen-oxygen combustion, utilizing reheat or superheated steam from the unit for high-temperature electrolysis during off-peak hours, and generating high-temperature steam through hydrogen-oxygen combustion to return to the boiler during peak hours to increase power generation capacity.

[0003] The aforementioned peak-shaving schemes for thermal power have improved the flexibility of unit operation to some extent, but they still have the following shortcomings: First, schemes such as molten salt thermal storage, hot water tanks, and electrode boilers have many heat exchange links, the energy storage medium has a relatively simple function, the energy conversion efficiency is limited, and the coupling depth with the original thermal power system is insufficient; Second, in peak-shaving schemes with high-temperature steam electrolysis as the core, the hydrogen and oxygen produced by electrolysis are mainly used as energy storage and energy release media, the reducing properties of hydrogen have not been further utilized, the system function is still limited to bidirectional electro-thermal conversion, and it has failed to form synergy with other resource conversion processes.

[0004] Meanwhile, desulfurized gypsum, a major industrial byproduct of wet flue gas desulfurization in coal-fired power plants, has long faced challenges in large-scale disposal and high-value utilization. Current applications of desulfurized gypsum primarily focus on building materials and fillers, with insufficient high-value recovery of sulfur. Gypsum can be converted into calcium sulfide under reducing atmosphere and high-temperature conditions. Further acidification of calcium sulfide can generate acidic gas containing H2S, which can then be converted into sulfur through the Claus sulfur production process. Therefore, coupling the processes of gypsum reduction, CaS acidification, and Claus sulfur production holds the potential to achieve both gypsum resource conversion and sulfur resource recovery.

[0005] However, the aforementioned gypsum-to-sulfur processes still have the following limitations: gypsum relies on carbon-containing or carbonaceous reducing agents (such as coal and coke) for high-temperature reduction, requiring a separate reducing gas preparation and purification system, resulting in high energy consumption and equipment complexity; the heating method mostly adopts direct contact heating, which leads to a decline in steam quality after heating, making it difficult to recover and reuse; and there is a lack of effective connection between the gypsum treatment process and the continuous operation of thermal power units, making it difficult to achieve energy and material synergy within the same system as the thermal power peak-shaving process. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a thermal power peak shaving system and method for producing sulfur from gypsum via high-temperature steam electrolysis coupling, which can realize thermal power peak shaving, graded utilization of hydrogen energy, resource-based conversion of gypsum into sulfur, and water / steam recycling.

[0007] The technical solution of the present invention is as follows: In a first aspect of the present invention, a thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur is provided, comprising a thermal power generation module, a high-temperature steam electrolysis module, a hydrogen-oxygen combustion module, and a hydrogen reduction gypsum to produce sulfur module. The thermal power generation module includes a coal-fired boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, and a condenser connected in sequence. The high-temperature steam electrolysis module includes an SOEC component for producing hydrogen and oxygen through high-temperature steam electrolysis, and its steam inlet is connected to the steam outlets of the high-pressure cylinder and the medium-pressure cylinder. The hydrogen-oxygen combustion module includes a hydrogen-oxygen combustion reactor, which is used to burn the hydrogen and oxygen generated by the SOEC component to produce high-temperature steam. The high-temperature steam is divided into three parts: the first part enters the coal-fired boiler, the second part enters the SOEC component, and the third part enters the heating side of the hydrogen reduction gypsum to sulfur production module. The hydrogen-reduced gypsum sulfur production module includes a hydrogen-reduced gypsum reactor and a CaS slurry acidification-Claus sulfur production unit connected in sequence. The hydrogen-reduced gypsum reactor is fed with hydrogen generated by the SOEC component, and the hydrogen acts as a reducing agent to reduce gypsum to CaS solid material. The CaS solid material is then passed through the CaS slurry acidification-Claus sulfur production unit to produce sulfur.

[0008] In some embodiments of the present invention, the thermal power generation module further includes a low-pressure regenerator, a deaerator, and a high-pressure regenerator; the condensate outlet of the condenser is connected to the coal-fired boiler in sequence via the low-pressure regenerator, the deaerator, and the high-pressure regenerator to form a steam-condensate circulation loop in the thermal power generation process.

[0009] In some embodiments of the present invention, the steam electrolysis module further includes a heat exchanger, a hydrogen primary compressor, an oxygen primary compressor, a hydrogen buffer / distribution tank, and an oxygen buffer / distribution tank; the hydrogen outlet of the SOEC module is connected to the hydrogen buffer / distribution tank via the heat exchanger and the hydrogen primary compressor, and the oxygen outlet of the SOEC module is connected to the oxygen buffer / distribution tank via the heat exchanger and the oxygen primary compressor.

[0010] In some embodiments of the present invention, the hydrogen buffer / distribution tank is connected to the hydrogen-oxygen burner via a first hydrogen branch, and a first hydrogen branch regulating valve is provided on the first hydrogen branch; the hydrogen buffer / distribution tank is connected to the hydrogen-reduced gypsum reactor via a second hydrogen branch, and a second hydrogen branch regulating valve is provided on the second hydrogen branch.

[0011] In some embodiments of the present invention, the oxygen buffer / distribution tank is connected to the hydrogen-oxygen burner via an oxygen branch, and an oxygen branch regulating valve is provided on the oxygen branch.

[0012] In some embodiments of the present invention, the steam outlet of the high-pressure cylinder is connected to the SOEC assembly via a reheat steam pipeline, and a reheat steam valve is provided on the reheat steam pipeline; the steam outlet of the intermediate-pressure cylinder is connected to the SOEC assembly via a superheat steam pipeline, and a superheat steam valve is provided on the superheat steam pipeline; the steam outlet of the hydrogen-oxygen combustion reactor is connected to the SOEC assembly via a make-up steam pipeline, and a make-up steam regulating valve is provided on the make-up steam pipeline.

[0013] In some embodiments of the present invention, a heating channel is provided inside the hydrogen-reduced gypsum reactor, and the heating channel is connected to the steam outlet of the hydrogen-oxygen combustion reactor through a pipe, and the heating channel indirectly exchanges heat with the reaction space inside the hydrogen-reduced gypsum reactor.

[0014] In some embodiments of the present invention, the CaS slurry acidification-Claus sulfur production module includes a CaS slurry preparation device, a CO2 acidification reactor, a gas-liquid separation device, and a Claus sulfur production device. The CaS solid material outlet of the hydrogen reduction gypsum reactor is connected to the CaS slurry preparation device, the CaS slurry preparation device is connected to the CO2 acidification reactor, and the gas outlet of the CO2 acidification reactor is connected to the Claus sulfur production device via the gas-liquid separation device.

[0015] In some embodiments of the present invention, the SOEC module operates at a temperature of 600°C to 1000°C. In a second aspect of the present invention, a method for operating a thermal power peak-shaving system for producing sulfur by steam electrolysis coupled with gypsum is provided, including a low-load operation mode and a peak-load operation mode. During off-peak load operation, high-temperature steam from the thermal power generation module is introduced into the SOEC module, and a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor is also introduced into the SOEC module to supplement the high-temperature steam and heat required by the SOEC module. The surplus energy during off-peak periods is used to drive the SOEC module to perform high-temperature steam electrolysis, generating hydrogen and oxygen. A portion of the hydrogen is fed into the hydrogen-reduction gypsum reactor as a gypsum reducing agent, while another portion of the hydrogen and oxygen is fed into the hydrogen-oxygen combustion reactor to generate high-temperature steam. This high-temperature steam is then used to heat the SOEC module and the hydrogen-reduction gypsum reactor. Gypsum is converted into CaS solid material, which is then dispersed in water to form a CaS slurry. CO2 is introduced into the CaS slurry for acidification, generating H2S-containing acidic gas. This H2S-containing acidic gas is then sent to the Claus sulfur production unit to generate sulfur. During peak load operation, the thermal power generation module stops drawing high-temperature steam to the SOEC module; a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor is returned to the coal-fired boiler to improve the power generation capacity of the thermal power unit; at the same time, another portion of the high-temperature steam continues to provide heat to the hydrogen reduction gypsum reactor and continues to provide hydrogen to the hydrogen reduction gypsum reactor, so that the gypsum reduction process, CaS slurry CO2 acidification process and Claus sulfur production process can continue to operate continuously; in addition, the hot water steam generated by hydrogen-oxygen combustion is isolated from the hydrogen reduction gypsum reaction materials, and the steam after heating is kept clean and returned to the SOEC module.

[0016] One or more technical solutions of the present invention have the following beneficial effects: (1) This invention utilizes the reheat steam and superheated steam in the thermal power generation module, as well as some of the high-temperature steam generated by the hydrogen-oxygen combustion reactor, as the steam source for the high-temperature steam electrolysis of the SOEC module. During periods of low electricity demand, it absorbs surplus energy and produces hydrogen and oxygen, thereby realizing the conversion of electrical energy and the cascade utilization of steam during the peak shaving process of thermal power.

[0017] (2) This invention uses hydrogen in stages for hydrogen-oxygen combustion and hydrogen reduction of gypsum. It utilizes the heat of hydrogen combustion to generate high-temperature water vapor and the reducing property of hydrogen to convert gypsum into CaS, thereby improving the comprehensive utilization efficiency of hydrogen. The hydrogen reduction of gypsum is coupled with the CO2 acidification of CaS slurry-Claus sulfur production process. Gypsum is converted into CaS solid material. After CaS solid material is dispersed in water to form CaS slurry, it is acidified with CO2 to generate acidic gas containing H2S. Finally, sulfur is generated through the Claus reaction, realizing the resource utilization of gypsum and sulfur recovery.

[0018] (3) The present invention sets up a low-load operation mode and a peak-load operation mode: during the low-load period, SOEC electrolysis and gypsum reduction are the main processes, and during the peak period, steam is not extracted from the thermal power unit to SOEC. The high-temperature steam generated by the hydrogen-oxygen combustion reactor is sent back to the boiler to assist in power generation, while the gypsum reduction and Claus sulfur production processes are still maintained. On the basis of retaining the original thermal system and peak-shaving function of the thermal power unit, the high-temperature steam electrolysis, hydrogen-oxygen combustion, hydrogen reduction of gypsum and Claus sulfur production processes are coupled, which has good engineering adaptability and continuous operation capability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur according to the present invention. Figure 2 This is a schematic diagram of the operating status of the system of the present invention in the off-peak load operation mode; Figure 3 This is a schematic diagram of the operating status of the system of the present invention under peak load operation mode.

[0020] In the diagram: 1. Coal-fired boiler; 2. High-pressure cylinder; 3. Medium-pressure cylinder; 4. Low-pressure cylinder; 5. Condenser; 6. Low-pressure regenerator; 7. Deaerator; 8. High-pressure regenerator; 9. SOEC assembly; 10. Heat exchanger; 11. Hydrogen primary compressor; 12. Oxygen primary compressor; 13. Hydrogen buffer / distribution tank; 14. Oxygen buffer / distribution tank; 15. Hydrogen-oxygen combustion reactor; 16. Gypsum feed silo; 17. Hydrogen-reduction gypsum reactor; 18. CaS slurry acidification-Claus sulfur production unit; 19. First hydrogen branch regulating valve; 20. Oxygen branch regulating valve; 21. Second hydrogen branch regulating valve; 22. Reheat steam valve; 23. Superheated steam valve; 24. SOEC make-up steam regulating valve; 25. Heating steam regulating valve. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Terminology Explanation: Main steam refers to the steam that enters the high-pressure cylinder of the steam turbine from the outlet of the coal-fired boiler.

[0024] Reheated steam refers to steam that has been used to perform work in the high-pressure cylinder of the steam turbine, then returned to the coal-fired boiler for reheating, and then fed back into the intermediate-pressure cylinder of the steam turbine to perform work.

[0025] Superheated steam refers to saturated steam that has been further heated by a heat exchanger at a higher temperature, resulting in a temperature exceeding the saturation temperature at its corresponding pressure.

[0026] SOEC modules, or solid oxide electrolyzer modules, are used to electrolyze water vapor into hydrogen and oxygen under high-temperature conditions.

[0027] Claus sulfur production refers to the sulfur recovery process in which acidic gas containing H2S reacts with SO2 to produce sulfur.

[0028] The CaS slurry CO2 acidification route refers to the process where CaS-containing solid materials are dispersed in water to form a CaS slurry, which then undergoes an acidification reaction under CO2 conditions to generate H2S-containing acidic gas, which is then further introduced into the Claus sulfur production unit to produce sulfur.

[0029] The system and method disclosed in this invention aim to achieve off-peak energy absorption, peak-hour auxiliary power generation, energy cascade utilization, and gypsum resource conversion during the operation of thermal power plants. This application shares the same application background as thermal power peak-shaving schemes based on high-temperature steam electrolysis and hydrogen-oxygen combustion, but this application further utilizes hydrogen generated by SOEC modules for gypsum hydrogen reduction, and couples the CaS solid product, after water dispersion and CO2 acidification to generate H2S, to the Claus sulfur production process. Example 1 In a typical embodiment of the present invention, a thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur is proposed, comprising a thermal power generation module, a high-temperature steam electrolysis module, a hydrogen-oxygen combustion module, and a hydrogen reduction gypsum to produce sulfur module. The thermal power generation module generates electricity and supplies high-temperature steam to the high-temperature steam electrolysis module. The high-temperature steam electrolysis module electrolyzes the steam at high temperature to generate hydrogen and oxygen, and supplies the hydrogen and oxygen to the hydrogen-oxygen combustion module. The hydrogen is also supplied to the hydrogen reduction gypsum to produce sulfur module as a reducing agent for gypsum. The hydrogen-oxygen combustion module burns the hydrogen and oxygen to generate high-temperature steam, which is divided into three parts: the first part is supplied to the thermal power generation module to improve the power generation capacity of the thermal power unit; the second part is supplied to the high-temperature steam electrolysis module to supplement the high-temperature steam; and the third part is supplied to the hydrogen reduction gypsum to produce sulfur module to provide heat for the gypsum reduction process.

[0030] Specifically, the thermal power generation module includes a coal-fired boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a condenser 5, a low-pressure regenerator 6, a deaerator 7, and a high-pressure regenerator 8 connected in sequence. The condensate outlet of the condenser 5 is connected to the coal-fired boiler 1 via the low-pressure regenerator 6, the deaerator 7, and the high-pressure regenerator 8 in sequence to form a steam-condensate circulation loop in the thermal power generation process. Among them, the high-pressure cylinder 2, the intermediate-pressure cylinder 3, and the low-pressure cylinder 4 constitute the main working equipment of the thermal power unit, while the low-pressure regenerator 6, the deaerator 7, and the high-pressure regenerator 8 are used to increase the feedwater temperature, remove dissolved oxygen, and improve the unit's thermal efficiency.

[0031] The high-temperature steam electrolysis module includes an SOEC component 9 for electrolyzing high-temperature steam to produce hydrogen and oxygen. Its steam inlet is connected to the steam outlets of the high-pressure cylinder 2 and the intermediate-pressure cylinder 3. It also includes a heat exchanger 10, a hydrogen primary compressor 11, an oxygen primary compressor 12, a hydrogen buffer / distribution tank 13, and an oxygen buffer / distribution tank 14. The hydrogen outlet of the SOEC component 9 is connected to the hydrogen buffer / distribution tank 13 via the heat exchanger 10 and the hydrogen primary compressor 11, and the oxygen outlet of the SOEC component 9 is connected to the oxygen buffer / distribution tank 14 via the heat exchanger 10 and the oxygen primary compressor 12. The hydrogen and oxygen produced by the electrolysis of the SOEC component 9 enter the heat exchanger 10 for cooling, and then enter the hydrogen buffer / distribution tank 13 and the oxygen buffer / distribution tank 14 respectively via the hydrogen primary compressor 11 and the oxygen primary compressor 12.

[0032] Furthermore, the hydrogen buffer / distribution tank 13 is connected to the hydrogen-oxygen combustion reactor 15 via a first hydrogen branch, and a first hydrogen branch regulating valve 19 is provided on the first hydrogen branch; the hydrogen buffer / distribution tank 13 is connected to the hydrogen-reduced gypsum reactor 17 via a second hydrogen branch, and a second hydrogen branch regulating valve 21 is provided on the second hydrogen branch. A portion of the hydrogen in the hydrogen buffer / distribution tank 13 enters the hydrogen-oxygen combustion reactor 15 via the first hydrogen branch regulating valve 19, and oxygen in the oxygen buffer / distribution tank 14 enters the hydrogen-oxygen combustion reactor 15 via the oxygen branch regulating valve 20. The oxygen buffer / distribution tank 14 is connected to the hydrogen-oxygen combustion reactor 15 via an oxygen branch, and an oxygen branch regulating valve 20 is provided on the oxygen branch. By adjusting the opening of the first hydrogen branch regulating valve 19, the second hydrogen branch regulating valve 21, and the oxygen branch regulating valve 20, the gas flow rate entering the hydrogen-oxygen combustion reactor 15 and the hydrogen reduction gypsum reactor 17 can be controlled to match the peak shaving requirements of thermal power and the requirements of gypsum reduction reaction.

[0033] The SOEC module 9 operates at a temperature of 600℃~1000℃. The high-temperature steam electrolyzed by the SOEC module 9 originates from the high-pressure cylinder 2 and intermediate-pressure cylinder 3 of the thermal power generation module, and the hydrogen-oxygen combustion reactor 15 of the hydrogen-oxygen combustion module. Specifically, the steam outlet of the high-pressure cylinder 2 is connected to the SOEC module 9 via a reheat steam pipeline, which is equipped with a reheat steam valve 22. The steam outlet of the intermediate-pressure cylinder 3 is connected to the SOEC module 9 via a superheat steam pipeline, which is equipped with a superheat steam valve 23. The reheat steam valve 22 and the superheat steam valve 23 are used to control the opening and closing and flow rate of the high-temperature steam extracted by the thermal power generation module. The steam outlet of the hydrogen-oxygen combustion reactor 15 is connected to the SOEC module 9 via a make-up steam pipeline, which is equipped with an SOEC make-up steam regulating valve 24 to regulate the total amount of high-temperature steam entering the SOEC module 9 from the hydrogen-oxygen combustion module.

[0034] The hydrogen-oxygen combustion module includes a hydrogen-oxygen combustion reactor 15, which is used to burn the hydrogen and oxygen generated by the SOEC component 9 to produce high-temperature steam. The high-temperature steam is divided into three parts: the first part enters the coal-fired boiler 1, the second part enters the SOEC component 9, and the third part enters the heating side of the hydrogen reduction gypsum to sulfur production module. Specifically, the high-temperature steam generated by the hydrogen-oxygen combustion reactor 15 is provided with three branches. The first branch is connected to the coal-fired boiler 1 to supplement the thermal power unit with high-temperature steam during peak electricity consumption periods to improve or maintain the subsequent turbine power generation capacity; the second branch is connected to the SOEC component 9 via the SOEC supplement steam regulating valve 24 to supplement the SOEC component 9 with the required high-temperature steam and heat; the third branch is connected to the heating side of the hydrogen reduction gypsum reactor 17 via the heating steam regulating valve 25 to supply heat to the gypsum hydrogen reduction reaction.

[0035] The hydrogen-reduction gypsum sulfur production module includes a hydrogen-reduction gypsum reactor 17 and a CaS slurry acidification-Claus sulfur production unit 18 connected in sequence. Hydrogen gas generated by the SOEC component 9 is introduced into the hydrogen-reduction gypsum reactor 17, and the hydrogen gas acts as a reducing agent to reduce gypsum to CaS solid material. The CaS solid material is then converted into sulfur through the CaS slurry acidification-Claus sulfur production unit 18. The solid inlet of the hydrogen-reduction gypsum reactor 17 is connected to the gypsum feed silo 16, and another portion of the hydrogen gas in the hydrogen buffer / distribution tank 13 enters the hydrogen-reduction gypsum reactor 17 through the second hydrogen branch regulating valve 21. Gypsum undergoes a reduction reaction under the action of hydrogen gas to produce CaS.

[0036] Furthermore, a heating channel is provided within the hydrogen-reduced gypsum reactor 17. This heating channel is connected to the steam outlet of the hydrogen-oxygen combustion reactor 15 via a pipe, and the heating channel indirectly exchanges heat with the reaction space within the hydrogen-reduced gypsum reactor 17. The high-temperature steam entering the heating side of the hydrogen-reduced gypsum reactor 17 primarily serves as a heating medium, rather than a gypsum reducing agent. The steam flows within the heat exchange wall, isolating it from the gypsum, H2, CaS, and sulfur-containing gases within the reactor; therefore, the steam output from the hydrogen-reduced gypsum reactor 17 and returned to the SOEC assembly 9 is clean steam after heating. The heating steam regulating valve 25 is used to regulate the amount of high-temperature steam entering the heating side of the hydrogen-reduced gypsum reactor 17.

[0037] Furthermore, the CaS slurry acidification-Claus sulfur production module includes a CaS slurry preparation device, a CO2 acidification reactor, a gas-liquid separation device, and a Claus sulfur production device. The CaS solid material outlet of the hydrogen reduction gypsum reactor 17 is connected to the CaS slurry preparation device, which is connected to the CO2 acidification reactor. The gas outlet of the CO2 acidification reactor is connected to the Claus sulfur production device via the gas-liquid separation device. The CaS-containing solid material output from the hydrogen reduction gypsum reactor 17 is first mixed with water and dispersed to form a CaS slurry. The CaS slurry then enters the CO2 acidification reactor. CO2 is introduced from the bottom, side, or gas distribution structure of the acidification reactor and reacts with the CaS in the slurry to produce acidic gas containing H2S and a solid slurry containing CaCO3. The H2S-containing acidic gas enters the Claus sulfur production section after gas-liquid separation. In the Claus sulfur production section, some of the H2S can be selectively oxidized to SO2 using some of the oxygen generated by SOEC component 9, or an appropriate amount of SO2-containing gas can be introduced to ensure the H2S to SO2 ratio meets the Claus reaction requirements, ultimately producing sulfur. The CaCO3-containing solid phase can be recovered as a byproduct or further processed after sedimentation, filtration, or centrifugation.

[0038] In this embodiment, the CO2 acidification reactor is provided with a CO2 inlet, which is located at the bottom, side or gas distribution structure of the CO2 acidification reactor, so that CO2 comes into contact with CaS slurry and reacts to generate acidic gas containing H2S and solid slurry containing CaCO3.

[0039] In this embodiment, the hydrogen produced by SOEC component 9 is not solely for storage, but is used in stages as a hydrogen-oxygen combustion fuel and a gypsum reducing agent. The oxygen produced by SOEC component 9 is used in hydrogen-oxygen combustion reactor 15 to burn with hydrogen and generate clean high-temperature steam. The clean high-temperature steam can be used for supplementing steam to SOEC component 9, supplying heat to hydrogen-reduced gypsum reactor 17, and being fed back to coal-fired boiler 1 during peak electricity consumption periods.

[0040] Example 2 In a typical embodiment of the present invention, a method for operating a thermal power peak-shaving system for producing sulfur by coupling water vapor electrolysis with gypsum is provided, including a low-load operation mode and a peak-load operation mode. During off-peak load operation, high-temperature steam from the thermal power generation module is introduced into SOEC module 9, and a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor 15 is also introduced into SOEC module 9 to supplement the high-temperature steam and heat required by SOEC module 9. The surplus energy during off-peak periods is used to drive high-temperature steam electrolysis in SOEC module 9 to generate hydrogen and oxygen. A portion of the hydrogen is introduced into hydrogen-reduced gypsum reactor 17 as a gypsum reducing agent, while another portion of the hydrogen and oxygen is introduced into hydrogen-oxygen combustion reactor 15 for combustion to generate high-temperature steam. This high-temperature steam is then used to heat SOEC module 9 and hydrogen-reduced gypsum reactor 17. Gypsum is converted into CaS solid material, which is then dispersed in water to form CaS slurry. CO2 is introduced into the CaS slurry for acidification, generating H2S-containing acidic gas. This H2S-containing acidic gas is then sent to Claus sulfur production unit 18 to generate sulfur.

[0041] Combination Figure 2 As shown, during periods of low electricity demand, the power grid load is low, and thermal power units are able to extract some high-temperature steam.

[0042] During off-peak periods, reheat steam valve 22 and superheat steam valve 23 open, allowing some of the reheat steam and superheat steam from the thermal power generation module to enter SOEC module 9. Simultaneously, SOEC supplementary steam regulating valve 24 opens, allowing some of the high-temperature steam generated by the hydrogen-oxygen combustion reactor 15 to enter SOEC module 9. SOEC module 9 electrolyzes the high-temperature steam to generate hydrogen and oxygen, thereby converting surplus energy during off-peak periods into chemical energy.

[0043] The hydrogen and oxygen generated by SOEC component 9 enter heat exchanger 10 for cooling. The cooled hydrogen enters hydrogen buffer / distribution tank 13 through hydrogen primary compressor 11, and the cooled oxygen enters oxygen buffer / distribution tank 14 through oxygen primary compressor 12.

[0044] During off-peak periods, the hydrogen-oxygen combustion reactor 15 does not supply high-temperature steam to the coal-fired boiler 1. Part of the hydrogen in the hydrogen buffer / distribution tank 13 enters the hydrogen-oxygen combustion reactor 15 via the first hydrogen branch regulating valve 19, and oxygen in the oxygen buffer / distribution tank 14 enters the hydrogen-oxygen combustion reactor 15 via the oxygen branch regulating valve 20. The two gases combust to produce high-temperature steam. Part of this high-temperature steam enters the SOEC assembly 9 via the SOEC supplement steam regulating valve 24, and the other part enters the heating side of the hydrogen-reduced gypsum reactor 17 via the heating steam regulating valve 25.

[0045] During off-peak periods, high-temperature steam generated by the hydrogen-oxygen combustion reactor 15 and regulated by the heating steam regulating valve 25 enters the heating channel of the hydrogen reduction gypsum reactor 17 to provide heat for the hydrogen reduction reaction of gypsum. The heated steam remains clean and returns to the inlet of SOEC component 9 along the return pipeline.

[0046] During periods of low energy consumption, another portion of the hydrogen in the hydrogen buffer / distribution tank 13 enters the hydrogen reduction gypsum reactor 17 via the second hydrogen branch regulating valve 21; the gypsum feed silo 16 supplies gypsum to the hydrogen reduction gypsum reactor 17. Gypsum is converted into CaS under hydrogen reducing atmosphere and high-temperature steam heating conditions.

[0047] During off-peak periods, the CaS-containing solid material output from the hydrogen-reduced gypsum reactor 17 enters the Claus sulfur production unit 18, where it is first dispersed in water to form a CaS slurry. Under CO2 conditions, the CaS slurry undergoes an acidification reaction, generating acidic gas containing H2S. This acidic gas is then adjusted and subjected to a Claus reaction to produce sulfur. Thus, during off-peak periods, not only is SOEC hydrogen production and storage completed, but gypsum resource conversion and sulfur production also continue.

[0048] During peak load operation, the thermal power generation module stops drawing high-temperature steam to SOEC component 9; a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor 15 is returned to the coal-fired boiler 1 to improve the power generation capacity of the thermal power unit; at the same time, another portion of the high-temperature steam continues to provide heat to the hydrogen reduction gypsum reactor 17 and continues to provide hydrogen to the hydrogen reduction gypsum reactor 17, so that the gypsum reduction process, CaS slurry CO2 acidification process and Claus sulfur production process can continue to operate continuously.

[0049] Combination Figure 3 During peak electricity consumption periods, when the grid load is high, thermal power units prioritize power generation.

[0050] During peak periods, reheat steam valve 22 and superheat steam valve 23 are closed, and the thermal power generation module no longer draws high-temperature steam into SOEC assembly 9. Therefore, the high-temperature steam generated by the thermal power unit is preferentially used to power generation in high-pressure cylinder 2, intermediate-pressure cylinder 3, and low-pressure cylinder 4.

[0051] During peak periods, the hydrogen-oxygen combustion reactor 15 can still utilize the hydrogen and oxygen stored in the hydrogen buffer / distribution tank 13 and the oxygen buffer / distribution tank 14 for combustion, generating high-temperature steam. A portion of this high-temperature steam is returned to the coal-fired boiler 1 to increase the power generation capacity of the thermal power unit or supplement steam heat; the other portion continues to supply heat to the hydrogen-reduced gypsum reactor 17 via the heating steam regulating valve 25. Simultaneously, the hydrogen buffer / distribution tank 13 continues to supply hydrogen to the hydrogen-reduced gypsum reactor 17 through the second hydrogen branch regulating valve 21, thus ensuring that the gypsum reduction process does not cease during peak operating conditions.

[0052] During peak periods, Claus sulfur production unit 18 continues to receive CaS-containing solid material from hydrogen-reduced gypsum reactor 17 and continuously performs CaS slurry preparation, CO2 acidification, H2S-containing acid gas generation, acid gas conditioning, and Claus sulfur production processes. In other words, gypsum reduction and subsequent Claus sulfur production processes can also operate continuously during peak periods.

[0053] During peak periods, the water vapor discharged from the heating channel of the hydrogen-reduced gypsum reactor 17 remains clean water vapor. This clean water vapor can be returned to the inlet of SOEC module 9 and reused during the electrolysis stage.

[0054] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur, characterized in that, This includes a thermal power generation module, a high-temperature steam electrolysis module, a hydrogen-oxygen combustion module, and a hydrogen reduction gypsum to sulfur production module; The thermal power generation module includes a coal-fired boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, and a condenser connected in sequence. The high-temperature steam electrolysis module includes an SOEC component for producing hydrogen and oxygen through high-temperature steam electrolysis, and its steam inlet is connected to the steam outlets of the high-pressure cylinder and the medium-pressure cylinder. The hydrogen-oxygen combustion module includes a hydrogen-oxygen combustion reactor, which is used to burn the hydrogen and oxygen generated by the SOEC component to produce high-temperature steam. The high-temperature steam is divided into three parts: the first part enters the coal-fired boiler, the second part enters the SOEC component, and the third part enters the heating side of the hydrogen reduction gypsum to sulfur production module. The hydrogen-reduced gypsum sulfur production module includes a hydrogen-reduced gypsum reactor and a CaS slurry acidification-Claus sulfur production unit connected in sequence. The hydrogen-reduced gypsum reactor is fed with hydrogen generated by the SOEC component, and the hydrogen acts as a reducing agent to reduce gypsum to CaS solid material. The CaS solid material is then passed through the CaS slurry acidification-Claus sulfur production unit to produce sulfur.

2. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The thermal power generation module also includes a low-pressure regenerator, a deaerator, and a high-pressure regenerator; the condensate outlet of the condenser is connected to the coal-fired boiler in sequence via the low-pressure regenerator, the deaerator, and the high-pressure regenerator to form a steam-condensate circulation loop in the thermal power generation process.

3. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The steam electrolysis module further includes a heat exchanger, a hydrogen primary compressor, an oxygen primary compressor, a hydrogen buffer / distribution tank, and an oxygen buffer / distribution tank; the hydrogen outlet of the SOEC module is connected to the hydrogen buffer / distribution tank via the heat exchanger and the hydrogen primary compressor, and the oxygen outlet of the SOEC module is connected to the oxygen buffer / distribution tank via the heat exchanger and the oxygen primary compressor.

4. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 3, characterized in that, The hydrogen buffer / distribution tank is connected to the hydrogen-oxygen burner via a first hydrogen branch, and a first hydrogen branch regulating valve is provided on the first hydrogen branch; the hydrogen buffer / distribution tank is connected to the hydrogen-reduced gypsum reactor via a second hydrogen branch, and a second hydrogen branch regulating valve is provided on the second hydrogen branch.

5. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 3, characterized in that, The oxygen buffer / distribution tank is connected to the hydrogen-oxygen burner via an oxygen branch, and an oxygen branch regulating valve is installed on the oxygen branch.

6. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The steam outlet of the high-pressure cylinder is connected to the SOEC assembly via a reheat steam pipeline, and a reheat steam valve is installed on the reheat steam pipeline; the steam outlet of the intermediate-pressure cylinder is connected to the SOEC assembly via a superheat steam pipeline, and a superheat steam valve is installed on the superheat steam pipeline; the steam outlet of the hydrogen-oxygen combustion reactor is connected to the SOEC assembly via a make-up steam pipeline, and a make-up steam regulating valve is installed on the make-up steam pipeline.

7. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The hydrogen-reduced gypsum reactor is equipped with a heating channel, which is connected to the steam outlet of the hydrogen-oxygen combustion reactor via a pipe. The heating channel indirectly exchanges heat with the reaction space inside the hydrogen-reduced gypsum reactor.

8. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The CaS slurry acidification-Claus sulfur production module includes a CaS slurry preparation device, a CO2 acidification reactor, a gas-liquid separation device, and a Claus sulfur production device. The CaS solid material outlet of the hydrogen reduction gypsum reactor is connected to the CaS slurry preparation device, the CaS slurry preparation device is connected to the CO2 acidification reactor, and the gas outlet of the CO2 acidification reactor is connected to the Claus sulfur production device via the gas-liquid separation device.

9. The thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur as described in claim 1, characterized in that, The SOEC module operates at a temperature of 600℃ to 1000℃.

10. A method for operating a thermal power peak-shaving system for high-temperature steam electrolysis coupled with gypsum to produce sulfur, as described in any one of claims 1-9, characterized in that, This includes off-peak load operation mode and peak load operation mode; During off-peak load operation, high-temperature steam from the thermal power generation module is introduced into the SOEC module, and a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor is also introduced into the SOEC module to supplement the high-temperature steam and heat required by the SOEC module. The surplus energy during off-peak periods is used to drive the SOEC module to perform high-temperature steam electrolysis, generating hydrogen and oxygen. A portion of the hydrogen is fed into the hydrogen-reduction gypsum reactor as a gypsum reducing agent, while another portion of the hydrogen and oxygen is fed into the hydrogen-oxygen combustion reactor to generate high-temperature steam. This high-temperature steam is then used to heat the SOEC module and the hydrogen-reduction gypsum reactor. Gypsum is converted into CaS solid material, which is then dispersed in water to form a CaS slurry. CO2 is introduced into the CaS slurry for acidification, generating H2S-containing acidic gas. This H2S-containing acidic gas is then sent to the Claus sulfur production unit to generate sulfur. During peak load operation, the thermal power generation module stops drawing high-temperature steam to the SOEC component; a portion of the high-temperature steam generated by the hydrogen-oxygen combustion reactor is returned to the coal-fired boiler to improve the power generation capacity of the thermal power unit; at the same time, another portion of the high-temperature steam continues to provide heat to the hydrogen reduction gypsum reactor and continues to provide hydrogen to the hydrogen reduction gypsum reactor, so that the gypsum reduction process, CaS slurry CO2 acidification process and Claus sulfur production process can continue to operate continuously.

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