Carbon dioxide capture and supercritical carbon dioxide Brayton cycle joint production system

Abstract

The invention relates to the technical field of carbon dioxide recovery and renewable energy utilization, in particular to a carbon dioxide capture and supercritical carbon dioxide Brayton cycle joint production system. The carbon dioxide trapping and purifying system and the supercritical carbon dioxide Brayton cycle power generation system are combined, carbon dioxide can be effectively trapped and purified, greenhouse gas emission is reduced, the trapped carbon dioxide can be directly used in the supercritical carbon dioxide Brayton cycle, and the power generation efficiency of the supercritical carbon dioxide Brayton cycle power generation system is improved. Stable and reliable carbon dioxide supply is provided for a circulating system, the storage and transportation cost of carbon dioxide is reduced, cyclic utilization of resources is achieved, the overall efficiency of the system is improved, and the problems that a carbon dioxide capturing and purifying system constructed based on a physical absorption method is huge in energy consumption and low in cost are solved. And the operation of the supercritical carbon dioxide Brayton cycle power generation system needs extra cold energy input, so that the operation cost is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide recovery and renewable energy utilization, and in particular to a carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system. Background Art

[0002] As one of the main greenhouse gases, carbon dioxide has a significant impact on the atmosphere and climate system. Carbon dioxide mainly comes from the combustion of fossil fuels, industrial production processes such as steel, cement, and chemicals, as well as agricultural activities. The sharp increase in carbon dioxide emissions has led to a series of serious environmental and ecological problems such as rising global temperatures, frequent extreme weather, and rising sea levels, posing a severe challenge to the human living environment. In order to curb climate change and strive to control the global temperature rise within 2°C, it is urgent to take effective measures to reduce the concentration of carbon dioxide in the atmosphere.

[0003] At present, the mainstream technologies for carbon dioxide emission reduction include carbon dioxide capture, utilization and storage system, chemical absorption method and physical absorption method. The full name of carbon dioxide capture, utilization and storage system is Carbon Capture, Utilization and Storage, referred to as CCUS. CCUS technology mainly captures carbon dioxide emitted by industry, purifies it and stores it underground or on the seabed, thereby effectively reducing the concentration of carbon dioxide in the atmosphere. At the same time, it can also provide new ways for the utilization of industrial by-products and economic development. Chemical absorption method and physical absorption method are the two main technologies for carbon dioxide capture. Chemical absorption method has a high capture efficiency for low-concentration carbon dioxide gas, but chemical absorption method has high requirements for equipment materials, and chemical absorbents are corrosive, which increases the construction and maintenance costs of equipment, and is prone to produce by-products that pollute the environment. Physical absorption method usually operates under low temperature or high pressure conditions, has high selectivity for gas components, and can effectively separate carbon dioxide on a large scale, but it also consumes a lot of energy and requires additional heat input.

[0004] In the field of electricity production, there are various ways of generating electricity, and each way faces different challenges and shortcomings while providing electricity. Thermal power generation is still the main way of generating electricity in the world, but its high carbon emissions are serious. Hydropower and nuclear power generation provide important base load power sources, but there are also environmental and safety challenges. Wind and solar power generation, as clean energy, have developed rapidly, but are limited by intermittent and efficiency issues. Supercritical fluid power generation technology, especially supercritical carbon dioxide power generation system, is expected to become an important development direction of future power generation technology due to its high efficiency, compact design, strong flexibility and environmental friendliness. The full name of supercritical carbon dioxide in English is Supercritical Carbon Dioxide, referred to as sCO2. However, sCO2 technology is still in the development and optimization stage.

[0005] At present, the carbon dioxide capture and purification system built based on the physical absorption method can adapt to carbon capture in different industrial scenarios, but it consumes huge energy and requires additional heat energy input, which limits its wide application.

[0006] The supercritical carbon dioxide Brayton cycle power generation system uses sCO2 as the working medium to achieve self-circulating digestion of CO2, but the system operation requires additional cooling input, which increases operating costs. Summary of the invention

[0007] In order to solve the problem that the carbon dioxide capture and purification system constructed based on the physical absorption method consumes huge energy and requires additional heat energy input, and the operation of the supercritical carbon dioxide Brayton cycle power generation system requires additional cold input, which increases operating costs, the purpose of the present invention is to provide a carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system.

[0008] The present invention can overcome the defects of the carbon dioxide capture and purification system and the supercritical carbon dioxide Brayton cycle power generation system constructed based on the physical absorption method, and realize the coupling matching and optimal operation of CCUS and the supercritical carbon dioxide Brayton cycle power generation system.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows.

[0010] The present invention provides a carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system, comprising a carbon dioxide capture and purification system and a supercritical carbon dioxide Brayton cycle power generation system.

[0011] The carbon dioxide capture and purification system comprises a carbon dioxide capture system and a carbon dioxide purification system which are connected in sequence; the carbon dioxide purification system comprises a condenser, a distillation tower, a reboiler and a subcooler; the hot end outlet of the condenser is connected to the first feed inlet of the distillation tower for distilling and purifying the condensed raw gas; the first discharge port of the distillation tower is connected to the first inlet of the reboiler for heating the material after preliminary distillation and purification.

[0012] The first outlet of the reboiler is connected to the second feed port of the distillation tower to perform distillation and purification on the heated material again; the second discharge port of the distillation tower is connected to the feed port of the subcooler to cool the material after distillation and purification again.

[0013] The supercritical carbon dioxide Brayton cycle power generation system includes a recompressor, a regenerator, a heat supply device and a power generation device; the second outlet of the reboiler is connected to the inlet of the recompressor, and the outlet of the recompressor is connected to the cold end inlet of the regenerator to absorb heat from the compressed carbon dioxide; the cold end outlet of the regenerator is connected to the first inlet of the heat supply device to convert the heat-absorbed carbon dioxide into supercritical carbon dioxide; the first outlet of the heat supply device is connected to the power generation device.

[0014] The exhaust gas outlet of the power generation device is connected to the hot end inlet of the regenerator, and the hot end outlet of the regenerator is connected to the second inlet of the reboiler.

[0015] Preferably, the carbon dioxide purification system comprises a refrigeration unit, and the outlet of the refrigeration unit is respectively connected to the cold end inlet of the condenser, the cold end inlet of the distillation tower and the cold end inlet of the subcooler.

[0016] The inlet of the refrigeration unit is respectively connected to the cold end outlet of the condenser, the cold end outlet of the distillation tower and the cold end outlet of the subcooler.

[0017] The power output end of the power generation device is connected to the power interface of the refrigeration unit.

[0018] Preferably, the power generation device includes a high-pressure turbine, a low-pressure turbine and a generator set, and the output shaft of the recompressor, the output shaft of the high-pressure turbine and the output shaft of the low-pressure turbine are connected to the drive shaft of the generator set.

[0019] Preferably, the first outlet of the heat supply device is connected to the inlet of the high-pressure turbine, and the outlet of the high-pressure turbine is connected to the second inlet of the heat supply device; the second outlet of the heat supply device is connected to the inlet of the low-pressure turbine.

[0020] The exhaust gas outlet of the low-pressure turbine is connected to the hot end inlet of the regenerator.

[0021] Preferably, a first check valve is provided in the connecting pipeline between the hot end outlet of the regenerator and the second inlet of the reboiler, so that the exhaust gas discharged from the hot end outlet of the regenerator enters the second inlet of the reboiler in a one-way manner.

[0022] A second check valve is provided on the connecting pipeline between the second outlet of the reboiler and the inlet of the recompressor, so that the carbon dioxide discharged from the second outlet of the reboiler can enter the inlet of the recompressor in one direction for compression.

[0023] Preferably, the carbon dioxide capture system comprises a buffer tank and a main compressor, the buffer tank is used to store carbon-containing raw gas; the outlet of the buffer tank is connected to the inlet of the main compressor; the outlet of the main compressor is connected to the carbon dioxide purification system.

[0024] Preferably, the carbon dioxide purification system comprises a water separator and a purification combination tower.

[0025] The outlet of the main compressor is connected to the inlet of the water separator, the outlet of the water separator is connected to the inlet of the purification tower, and the outlet of the purification combination tower is connected to the hot end inlet of the condenser.

[0026] Preferably, the purification combination tower comprises a drying tower, an adsorption tower and a purification tower, which are connected in sequence to purify the raw gas.

[0027] Preferably, the carbon dioxide purification system comprises a CO2 storage tank, and the discharge port of the subcooler is connected to the inlet of the CO2 storage tank to store the purified carbon dioxide.

[0028] Beneficial effects of the present invention:

[0029] 1. The present invention combines a carbon dioxide capture and purification system with a supercritical carbon dioxide Brayton cycle power generation system to effectively capture and purify carbon dioxide, reduce greenhouse gas emissions, and can directly use the captured carbon dioxide in a supercritical carbon dioxide Brayton cycle, thereby providing a stable and reliable supply of carbon dioxide for the circulation system, reducing the storage and transportation costs of carbon dioxide, achieving the recycling of resources, and improving the overall efficiency of the system.

[0030] 2. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system provided by the present invention can realize the complementary sharing of heat, cold energy and electric energy between systems. The waste heat of the supercritical carbon dioxide Brayton cycle power generation system provides the required heat for the reboiler in the carbon dioxide capture and purification system, and the reboiler provides cold and carbon dioxide for the supercritical carbon dioxide Brayton cycle power generation system, which greatly improves the overall thermal efficiency of the system. The supercritical carbon dioxide Brayton cycle power generation system provides the required electric energy for the high-energy consumption refrigeration unit in the carbon dioxide capture and purification system.

[0031] 3. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system provided by the present invention can simultaneously produce additional pure liquid carbon dioxide and industrial electricity, and has high economic benefits. Through system integration, the equipment investment and operating costs for separate carbon dioxide processing and energy conversion are reduced. The efficient energy conversion system can increase power generation or other energy output and increase economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system provided in one embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 1. Buffer tank; 2. Main compressor; 3. Water separator; 4. Purification combination tower; 5. Condenser; 6. Distillation tower; 7. Reboiler; 8. Subcooler; 9. CO2 storage tank; 10. Refrigeration unit; 11. Recompressor; 12. High-pressure turbine; 13. Low-pressure turbine; 14. Generator; 15. Heating device; 16. Regenerator; 17. First check valve; 18. Second check valve. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0037] The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system of the present invention has a wide range of applications. It can be applied not only to thermal power plants, but also to other industrial fields that require efficient thermal energy conversion, such as chemical plants, steel plants, cement plants, etc.; and it has high construction flexibility, and system components such as purification combination towers can be adjusted and optimized according to different industrial needs, thereby improving the adaptability and popularity of the system.

[0038] In addition, the carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system of the present invention has a high degree of integration. Combining carbon dioxide capture and purification with the supercritical carbon dioxide Brayton cycle system can reduce intermediate links, reduce energy consumption, and improve the overall efficiency of the system. This integrated design can be used as a new model to provide innovative solutions for the fields of energy and environmental protection.

[0039] The present invention can effectively capture and purify carbon dioxide, reduce greenhouse gas emissions, and can directly use the captured carbon dioxide in the Brayton cycle, reducing storage and transportation costs and realizing resource recycling. The present invention can achieve complementary sharing of heat and cold energy, electric energy and carbon dioxide between systems, and can produce additional pure liquid CO2 and industrial electricity. Through system integration, the present invention reduces the equipment investment and operating costs of separate carbon dioxide processing and energy conversion. The efficient energy conversion system can increase power generation or other energy output and increase economic benefits.

[0040] The technical solution of the present invention is further described below through specific embodiments. In the following embodiments, the methods described are conventional methods unless otherwise specified; and the equipment described are commercially available unless otherwise specified.

[0041] like Figure 1 , a carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system, including a carbon dioxide capture and purification system and a supercritical carbon dioxide Brayton cycle power generation system.

[0042] The carbon dioxide capture and purification system is mainly used to capture, purify and store carbon-containing raw gas. The carbon dioxide capture and purification system includes a buffer tank 1, a main compressor 2, a water separator 3, a purification combination tower 4, a condenser 5, a distillation tower 6, a reboiler 7, a subcooler 8, a CO2 storage tank 9 and a refrigeration unit 10.

[0043] The outlet of the buffer tank 1 is connected to the inlet of the main compressor 2, the outlet of the main compressor 2 is connected to the inlet of the water separator 3, the outlet of the water separator 3 is connected to the inlet of the purification tower 4, the outlet of the purification combination tower 4 is connected to the hot end inlet of the condenser 5, the hot end outlet of the condenser 5 is connected to the first feed port of the distillation tower 6, the first discharge port of the distillation tower 6 is connected to the first inlet of the reboiler 7, the first outlet of the reboiler 7 is connected to the second feed port of the distillation tower 6, the second discharge port of the distillation tower 6 is connected to the feed port of the subcooler 8, and the discharge port of the subcooler 8 is connected to the inlet of the CO2 storage tank 9. The outlet of the refrigeration unit 10 is respectively connected to the cold end inlet of the condenser 5, the cold end inlet of the distillation tower 6, and the cold end inlet of the subcooler 8; the inlet of the refrigeration unit 10 is respectively connected to the cold end outlet of the condenser 5, the cold end outlet of the distillation tower 6, and the cold end outlet of the subcooler 8.

[0044] Specifically, the buffer tank 1 is used to store raw gas, which is carbon-containing tail gas. For example, the raw gas mainly comes from carbon-containing tail gas discharged from thermal power plants, natural gas processing plants, chemical plants, steel plants, cement plants, etc. The buffer tank 1 can balance the flow and pressure of the raw gas, so that the raw gas with balanced flow and pressure enters the main compressor 2.

[0045] The main compressor 2 is used to compress the raw material gas from the buffer tank 1 and make the pressure of the compressed raw material gas reach 0.5 MPa to 5 MPa.

[0046] The water separator 3 is used to separate the water in the raw gas after the pressure is increased, so as to remove the water and improve the purity of the raw gas.

[0047] The purification combination tower 4 is used to perform multiple purifications on the raw gas from which water has been removed, such as drying, adsorption and purification, etc., to further remove impurities and improve the purity of the raw gas. For example, the purification combination tower 4 includes a drying tower, an adsorption tower and a purification tower, which are connected in sequence; the raw gas separated by the water separator 3 enters the drying tower, the adsorption tower and the purification tower in sequence for multiple purifications to remove impurities, and the purified raw gas enters the hot end inlet of the condenser 5 from the outlet of the purification combination tower 4.

[0048] The condenser 5 is used to cool and condense the purified raw gas. The cold source of the condenser 5 comes from the refrigeration unit 10.

[0049] The distillation tower 6 is used to perform deep distillation and separation on the condensed raw gas. The reboiler 7 is used to heat the material after preliminary distillation. Specifically, the first feed port of the distillation tower 6 is located in the middle and upper section of the distillation tower 6, the first discharge port of the distillation tower 6 is located at the bottom of the distillation tower 6, and the second feed port and the second discharge port of the distillation tower 6 are both located in the middle and lower section of the distillation tower 6. The cold end inlet and the cold end outlet of the distillation tower 6 are both located at the top of the distillation tower 6. The condensed raw gas enters the distillation tower through the first feed port of the distillation tower for further separation, and the separated raw gas enters the reboiler 7 from the first outlet of the distillation tower 6 for heating, and the heated raw gas is returned to the distillation tower 6 from the second feed port of the distillation tower 6 for further separation, and the material after deep distillation is sent to the supercooler 8.

[0050] The supercooler 8 is used to further cool the material after deep distillation and achieve high purity, for example, more than 95%. The supercooled high-purity carbon dioxide is transported to the CO2 storage tank 9 for storage.

[0051] The refrigeration unit 10 is used to provide a cold source, which completes a cooling cycle through the cold end of the condenser 5, the top of the distillation tower 6, and the cold end of the subcooler 8, ensuring that the temperatures of the condenser 5, the distillation tower 6, and the subcooler 8 are controlled within a suitable range.

[0052] The specific working process of the carbon dioxide capture and purification system is as follows: the carbon-containing tail gas raw gas discharged from thermal power plants, natural gas processing plants, chemical plants, steel plants, cement plants, etc. is sent to the buffer tank 1, and the raw gas after balancing the flow and pressure enters the main compressor 2. After compression, the raw gas pressure reaches 0.5MPa~5MPa, and then passes through the water separator 3, and the water in the raw gas is separated. The raw gas is multiple purified in the purification combination tower 4 through the drying tower, adsorption tower, purification tower, etc. to remove impurities. The purified gas enters the hot end of the condenser 5 from the outlet of the purification combination tower 4, and the gas is cooled and condensed. Then the raw gas is further separated in the distillation tower through the first feed port in the middle and upper part of the distillation tower 6, and enters the reboiler 7 from the first discharge port at the bottom of the distillation tower 6 for heating and returns it to the middle and lower part of the distillation tower 6 for further separation. The material after deep distillation is sent to the subcooler 8 for further cooling and high purity, and the supercooled high-purity carbon dioxide is transported to the CO2 storage tank 9 for storage. The refrigeration unit 10 provides cooling, and completes the cooling cycle through the cold end of the condenser 5, the top of the distillation tower 6, and the cold end of the subcooler 8, ensuring that the temperature of each part is controlled within a suitable range.

[0053] It should be noted that the raw gas entering the buffer tank 1 can come from the carbon-containing exhaust gas emitted by natural gas processing plants, chemical plants, power plants, steel plants, cement plants, etc. The purification combination tower 4 can be composed of a combination of multiple types of towers with different functions such as drying towers, adsorption towers, purification towers, etc. The specific number and type of combinations can be determined according to the type of raw gas. The large amount of electricity consumed by the refrigeration unit 10 is provided by the generator set 14 in the Brayton power generation system.

[0054] On the basis of the above-mentioned embodiment, as a more preferred embodiment, the supercritical carbon dioxide Brayton cycle power generation system includes a re-compressor 11, a high-pressure turbine 12, a low-pressure turbine 13, a generator set 14, a heating device 15 and a heat regenerator 16.

[0055] The outlet of the recompressor 11 is connected to the cold end inlet of the regenerator 16, the cold end outlet of the regenerator 16 is connected to the first inlet of the heating device 15, the first outlet of the heating device 15 is connected to the inlet of the high-pressure turbine 12, the outlet of the high-pressure turbine 12 is connected to the second inlet of the heating device 15, and the second outlet of the heating device 15 is connected to the inlet of the low-pressure turbine 13; the output shaft of the recompressor 11, the output shaft of the high-pressure turbine 12 and the output shaft of the low-pressure turbine 13 are connected to the drive shaft of the generator set 14, and the outlet of the low-pressure turbine 13 is connected to the hot end inlet of the regenerator 16. The power output end of the generator set 14 is connected to the power interface of the refrigeration unit 10.

[0056] It should be noted that the hot end outlet of the regenerator 16 is connected to the second inlet of the reboiler 7, and a first check valve 17 is connected to the connecting pipeline between the hot end outlet of the regenerator 16 and the second inlet of the reboiler 7, so that the regenerator 16 and the reboiler 7 are connected in a one-way manner. The second outlet of the reboiler 7 is connected to the inlet of the recompressor 11, and a second check valve 18 is connected to the connecting pipeline between the second outlet of the reboiler 7 and the inlet of the recompressor 11, so that the reboiler 7 and the recompressor 11 are connected in a one-way manner.

[0057] Specifically, the reboiler 7 is used to provide high-temperature carbon dioxide gas at 30°C to 100°C and with a certain pressure of 0.5MPa to 5MPa. The low-temperature carbon dioxide gas at -30°C to 10°C but with a certain pressure of 0.5MPa to 5MPa is heated by the reboiler 7 to be converted into high-temperature carbon dioxide gas with a certain pressure, and then enters the recompressor 11 for compression.

[0058] The recompressor 11 is used to compress the high-temperature and pressured carbon dioxide gas from the reboiler 7, and to make the pressure of the compressed raw gas reach 10 MPa to 25 MPa.

[0059] The regenerator 16 is used to perform heat exchange on the pressurized carbon dioxide gas so that the carbon dioxide gas after absorbing heat enters the heat supply device 15. The regenerator 16 can also recover heat from the exhaust gas after expansion and work by the high-pressure turbine 12 and the low-pressure turbine 13. That is, the heat source of the regenerator 16 mainly comes from the exhaust gas after expansion and work by the high-pressure turbine 12 and the low-pressure turbine 13, and the compressed carbon dioxide from the recompressor 11 is heated by the reflux heat.

[0060] The heating device 15 is used to further heat the carbon dioxide gas after absorbing heat, so that the heated carbon dioxide gas is converted into a supercritical state to form supercritical carbon dioxide. The supercritical carbon dioxide output by the heating device 15 directly enters the high-pressure turbine 12 and the low-pressure turbine 13. The heating device 15 can also reheat the supercritical carbon dioxide output by the high-pressure turbine 12, and the reheated supercritical carbon dioxide enters the low-pressure turbine 13 to generate electricity again.

[0061] The high-pressure turbine 12 and the low-pressure turbine 13 are used to expand the supercritical carbon dioxide to do work, and the expansion drives the turbine to do work and generate electricity. The supercritical carbon dioxide output by the high-pressure turbine 12 enters the heating device 15 for heat recovery, and the supercritical carbon dioxide after heat recovery enters the low-pressure turbine 13 to generate electricity again. The exhaust gas output by the low-pressure turbine 13 enters the regenerator 16 to recover heat from the exhaust gas.

[0062] The generator set 14 is connected to the recompressor 11, the high-pressure turbine 12 and the low-pressure turbine 13 through the rotor shaft. Among them, the output shafts of the high-pressure turbine 12 and the low-pressure turbine 13 are connected to the drive shaft of the generator set 14. When the blades of the high-pressure turbine 12 and the low-pressure turbine 13 are driven to rotate by the supercritical carbon dioxide fluid, the rotor shaft also rotates, thereby driving the drive shaft of the generator set 14 to rotate. The high-pressure turbine 12 and the low-pressure turbine 13 use the pressure difference and temperature difference of the supercritical carbon dioxide fluid to generate kinetic energy and convert the kinetic energy into mechanical energy. The mechanical energy is converted into electrical energy through the rotation of the drive shaft of the generator set 14. It should be noted that the generator set 14, the high-pressure turbine 12 and the low-pressure turbine 13 are all existing structures and can be directly purchased from the market.

[0063] The specific working process of the supercritical carbon dioxide Brayton cycle power generation system is: when the entire carbon dioxide capture and purification system is running stably, the supercritical carbon dioxide Brayton cycle power generation system is started, the first check valve 17 and the second check valve 18 are opened, and the low-temperature but pressured carbon dioxide gas is pressurized by the reboiler 7 and the recompressor 11 and enters the regenerator 16 to absorb heat, and then enters the heating device 15 to be further heated to a supercritical state; the supercritical carbon dioxide output by the heating device 15 directly enters the high-pressure turbine 12 and the low-pressure turbine 13 to drive the turbine through expansion to perform work and generate electricity, and the supercritical carbon dioxide output by the high-pressure turbine 12 is then reheated by the heating device 15 and enters the low-pressure turbine 13 to generate electricity again, and the exhaust gas after work enters the regenerator 16 to recover heat. The carbon dioxide output from the hot end of the regenerator 16 enters the reboiler 7 for further cooling and provides heat for the reboiling process of the distillation tower 6. Then the second outlet of the reboiler 7 is connected to the inlet of the recompressor 11 through the second check valve 18 to complete the closed recycling of the carbon dioxide until the whole system reaches stability.

[0064] It should be noted that one embodiment of the present invention combines a carbon dioxide capture and purification system with a supercritical carbon dioxide Brayton cycle power generation system, which can effectively capture and purify carbon dioxide, reduce greenhouse gas emissions, and can directly use the captured carbon dioxide in the supercritical carbon dioxide Brayton cycle, thereby providing a stable and reliable supply of carbon dioxide for the circulation system, reducing the storage and transportation costs of carbon dioxide, realizing the recycling of resources, and improving the overall efficiency of the system.

[0065] The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system provided in one embodiment of the present invention can realize the complementary sharing of heat, cold energy and electric energy between systems. The waste heat of the supercritical carbon dioxide Brayton cycle power generation system provides the required heat for the reboiler 7 in the carbon dioxide capture and purification system, and the reboiler 7 provides cold capacity and carbon dioxide for the supercritical carbon dioxide Brayton cycle power generation system, which greatly improves the overall thermal efficiency of the system. The supercritical carbon dioxide Brayton cycle power generation system provides the required electric energy for the high-energy consumption refrigeration unit 10 in the carbon dioxide capture and purification system.

[0066] The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system provided in one embodiment of the present invention can simultaneously produce additional pure liquid carbon dioxide and industrial electricity, and has high economic benefits. Through system integration, the equipment investment and operating costs for separate carbon dioxide processing and energy conversion are reduced. The efficient energy conversion system can increase power generation or other energy output and increase economic benefits.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system, characterized in that: Including carbon dioxide capture and purification system and supercritical carbon dioxide Brayton cycle power generation system; The carbon dioxide capture and purification system comprises a carbon dioxide capture system and a carbon dioxide purification system connected in sequence; the carbon dioxide purification system comprises a condenser, a distillation tower, a reboiler and a subcooler; the hot end outlet of the condenser is connected to the first feed inlet of the distillation tower, so as to distill and purify the condensed raw gas; the first discharge port of the distillation tower is connected to the first inlet of the reboiler, so as to heat the material after preliminary distillation and purification; The first outlet of the reboiler is connected to the second feed port of the distillation tower to perform distillation and purification on the heated material again; the second outlet of the distillation tower is connected to the feed port of the subcooler to cool the material after distillation and purification again; The supercritical carbon dioxide Brayton cycle power generation system comprises a recompressor, a regenerator, a heat supply device and a power generation device; the second outlet of the reboiler is connected to the inlet of the recompressor, and the outlet of the recompressor is connected to the cold end inlet of the regenerator to absorb heat from the compressed carbon dioxide; the cold end outlet of the regenerator is connected to the first inlet of the heat supply device to convert the carbon dioxide after absorption into supercritical carbon dioxide; the first outlet of the heat supply device is connected to the power generation device; The exhaust gas outlet of the power generation device is connected to the hot end inlet of the regenerator, and the hot end outlet of the regenerator is connected to the second inlet of the reboiler.

2. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 1, characterized in that: The carbon dioxide purification system comprises a refrigeration unit, the outlet of which is respectively connected to the cold end inlet of the condenser, the cold end inlet of the distillation tower and the cold end inlet of the subcooler; The inlet of the refrigeration unit is respectively connected to the cold end outlet of the condenser, the cold end outlet of the distillation tower and the cold end outlet of the subcooler; The power output end of the power generation device is connected to the power interface of the refrigeration unit.

3. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 1, characterized in that: The power generation device includes a high-pressure turbine, a low-pressure turbine and a generator set. The output shaft of the recompressor, the output shaft of the high-pressure turbine and the output shaft of the low-pressure turbine are connected to the driving shaft of the generator set.

4. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 3, characterized in that: The first outlet of the heat supply device is connected to the inlet of the high-pressure turbine, and the outlet of the high-pressure turbine is connected to the second inlet of the heat supply device; the second outlet of the heat supply device is connected to the inlet of the low-pressure turbine; The exhaust gas outlet of the low-pressure turbine is connected to the hot end inlet of the regenerator.

5. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 1, characterized in that: A first check valve is provided in the connecting pipeline between the hot end outlet of the regenerator and the second inlet of the reboiler, so that the exhaust gas discharged from the hot end outlet of the regenerator enters the second inlet of the reboiler in a one-way manner; A second check valve is provided on the connecting pipeline between the second outlet of the reboiler and the inlet of the recompressor, so that the carbon dioxide discharged from the second outlet of the reboiler can enter the inlet of the recompressor in one direction for compression.

6. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 1, characterized in that: The carbon dioxide capture system includes a buffer tank and a main compressor. The buffer tank is used to store carbon-containing raw gas; the outlet of the buffer tank is connected to the inlet of the main compressor; the outlet of the main compressor is connected to the carbon dioxide purification system.

7. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 6, characterized in that: The carbon dioxide purification system includes a water separator and a purification combination tower; The outlet of the main compressor is connected to the inlet of the water separator, the outlet of the water separator is connected to the inlet of the purification tower, and the outlet of the purification combination tower is connected to the hot end inlet of the condenser.

8. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 7, characterized in that: The purification combination tower comprises a drying tower, an adsorption tower and a purification tower, which are connected in sequence and are used to purify the raw gas.

9. The carbon dioxide capture and supercritical carbon dioxide Brayton cycle combined production system according to claim 1, characterized in that: The carbon dioxide purification system comprises a CO2 storage tank, and the discharge port of the supercooler is connected to the inlet of the CO2 storage tank to store the purified carbon dioxide.

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