System and method for capturing co2 from coal-fired power plants using solar thermal and curtailed wind and solar power

Abstract

The application provides a system and method for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy, wherein the system comprises a coal-fired power plant, a carbon capture system, a solar heat collection system, a wind power plant and / or a light power plant and a CO2 utilization or storage system, a flue gas discharge pipeline of the coal-fired power plant is communicated with the carbon capture system to provide flue gas for the carbon capture system, the carbon capture system is further communicated with the CO2 utilization or storage system to utilize or store the captured CO2; the wind power plant and / or the light power plant are used to provide electric energy for power-consuming equipment in the carbon capture system, and the solar heat collection system is used to provide heat energy for heat-consuming equipment in the carbon capture system. The application reasonably uses solar heat collection and abandoned wind and light energy for carbon capture, and can significantly reduce the abandoned wind and light rate and avoid a series of problems caused by frequent deep peak shaving of the coal-fired power plant while capturing CO2 with low carbon.

Description

TECHNICAL FIELD

[0001] The present application relates to a system and method for capturing CO2 of coal-fired power plants by solar heat collection and abandoned wind and light electric energy, belonging to the field of low-carbon energy technology. BACKGROUND

[0002] At present, the existing "double carbon" target makes the thermal power generation, which accounts for the largest proportion of carbon emissions, the most concerned. It is urgent to carry out carbon capture and reconstruction of coal-fired power plants.

[0003] Developing low-carbon energy is one of the main ways to reduce carbon emissions. In recent years, China has actively carried out the construction of new energy industries such as wind power and photovoltaic power generation, but because of the difficulty in consumption, it has led to a high rate of abandoned wind and light. If the abandoned wind and light rate is reduced, it will lead to frequent and deep peaking of thermal power plants, reducing the economy of thermal power generation, and easily causing problems such as thermal fatigue failure of boiler heating surface. How to reduce the abandoned wind and light rate while avoiding frequent and deep peaking of thermal power plants is one of the research hotspots in the field of electric power. With the proposal of China's "double carbon" target, carbon capture, utilization and storage (CCUS) technology will play an irreplaceable role in achieving the "carbon neutral" target by 2060 in China. This technology is widely recognized internationally as one of the main technical means for humans to effectively respond to climate change problems. According to the IPCC assessment report, CCUS is an indispensable technical means for fossil energy utilization system to achieve carbon emission reduction at the present stage.

[0004] At present, the carbon capture system used in coal-fired power plants includes a solar heating type absorption heat pump driven coal-fired power plant carbon capture system and a solar organic Rankine cycle assisted vacuum variable pressure and temperature coupled adsorption carbon capture system. The former mainly includes a carbon dioxide capture unit, a low-temperature solar heat collection unit, an absorption heat pump unit, and a steam turbine and a low-pressure feedwater heater in the power generation system of the power plant. The latter mainly provides the required power and heat for the vacuum variable pressure and temperature coupled adsorption carbon capture by the solar organic Rankine cycle, while ensuring the purity, recovery rate and yield of the carbon dioxide product gas. Although both technologies can achieve carbon capture in coal-fired power plants to some extent, they also have certain drawbacks. For example, the solar heating type absorption heat pump driven coal-fired power plant carbon capture system itself will produce carbon emissions, which cannot fundamentally solve the problem of carbon emissions. The vacuum variable pressure and temperature coupled adsorption carbon capture system assisted by the solar organic Rankine cycle is a carbon capture method that applies the steam extraction function of the traditional steam turbine. The heat required by the organic amine carbon capture system regeneration tower will cause a certain degree of carbon emissions in carbon capture, and the energy source is single, which cannot guarantee the normal operation of the system in the event of an emergency.

[0005] In addition, thermal power in China is still the main power generation method, and the installed capacity still accounts for a large proportion. To achieve the double carbon goal, the carbon emission problem of the thermal power plant in China must be reasonably solved.

[0006] Therefore, it has become a technical problem to be solved in the field to provide a new system and method for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy. SUMMARY

[0007] In order to solve the above-mentioned shortcomings and deficiencies, one object of the present application is to provide a system for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy.

[0008] Another object of the present application is also to provide a method for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy. The present application reasonably uses solar heat collection and abandoned wind and light energy for carbon capture, which can significantly reduce the abandoned wind and light rate and avoid a series of problems caused by frequent deep peak shaving of the coal-fired power plant while capturing CO2 at a low carbon.

[0009] In order to achieve the above object, in one aspect, the present application provides a system for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy, wherein the system comprises: a coal-fired power plant, a carbon capture system, a solar heat collection system, a wind power plant and / or a light power plant, and a CO2 utilization or storage system, a flue gas discharge pipeline of the coal-fired power plant is communicated with the carbon capture system to provide flue gas for the carbon capture system, and the carbon capture system is further communicated with the CO2 utilization or storage system to utilize or store the captured CO2.

[0010] The wind power plant and / or the light power plant are used to provide electric energy for power-consuming equipment in the carbon capture system, and the solar heat collection system is used to provide thermal energy for heat-consuming equipment in the carbon capture system.

[0011] As a specific embodiment of the above-mentioned system of the present application, the system further comprises a compressor, and the carbon capture system is communicated with the CO2 utilization or storage system through the compressor via a pipeline.

[0012] As a specific embodiment of the above-mentioned system of the present application, preferably, the wind power plant and / or the light power plant are further used to provide electric energy for the compressor.

[0013] The compressor is a conventional device.

[0014] As a specific embodiment of the above-mentioned system of the present application, the carbon capture system is an MEA carbon capture system.

[0015] As a specific embodiment of the above-mentioned system of the present application, the MEA carbon capture system comprises an absorption tower, a regeneration tower, a heat exchanger and a reboiler, the gas inlet of the absorption tower is communicated with the flue gas discharge pipeline of the coal-fired power plant, the rich liquid outlet of the absorption tower is communicated with the rich liquid inlet of the regeneration tower via a rich liquid pump and a heat exchanger, the lean liquid outlet of the regeneration tower is communicated with the lean liquid inlet of the absorption tower via a lean liquid pump and a heat exchanger; the regeneration tower is also communicated with the reboiler to heat the rich liquid in the regeneration tower.

[0016] The wind power plant and / or the light power plant are used to provide electric energy for the rich liquid pump and the lean liquid pump, and the solar heat collection system is used to provide heat energy for the reboiler.

[0017] As a specific embodiment of the above-mentioned system of the present application, the wind power plant and / or the light power plant are also used to provide energy for the reboiler.

[0018] The absorption tower, the regeneration tower, the heat exchanger and the reboiler used in the MEA carbon capture system are all conventional devices.

[0019] As a specific embodiment of the above-mentioned system of the present application, the solar heat collection system comprises a solar heat collector, an energy storage unit and a boiler, the solar heat collector is communicated with the energy storage unit through a first heat pump to store the heat energy collected by the solar heat collector in the energy storage unit through the first heat pump, and the energy storage unit is communicated with the boiler through a second heat pump to supply the heat energy stored in the energy storage unit to the boiler through the second heat pump, so that water vapor is generated in the boiler to provide heat energy for the heat-consuming devices in the carbon capture system.

[0020] As a specific embodiment of the above-mentioned system of the present application, the solar heat collector is a solar heat collection panel.

[0021] The solar heat collector, the energy storage unit, the boiler and the heat pump used in the solar heat collection system are all conventional devices.

[0022] As a specific embodiment of the above-mentioned system of the present application, the energy storage unit is a lithium ion battery.

[0023] In some embodiments of the present application, the lithium ion battery may, for example, be a lithium ion battery commonly used in the field of new energy vehicles.

[0024] As a specific embodiment of the above-mentioned system of the present application, the wind power plant comprises a wind turbine, a PMSG, an AC / DC and a DC / AC, the wind turbine is electrically connected with the power grid in sequence via the PMSG, the AC / DC and the DC / AC.

[0025] The wind power generator, the PMSG, the AC / DC and the DC / AC used by the wind power plant are all conventional devices.

[0026] As a specific embodiment of the above-mentioned system of the present application, the photoelectric plant comprises solar panels and a controller, and the solar panels are electrically connected to the power grid via the controller.

[0027] The solar panels and the controller used by the photoelectric plant are all conventional devices.

[0028] As a specific embodiment of the above-mentioned system of the present application, the system further comprises an electric energy storage device for storing the excess electric energy generated by the wind power plant and / or the photoelectric plant.

[0029] As a specific embodiment of the above-mentioned system of the present application, the electric energy storage device is an electric energy storage device composed of waste lithium batteries.

[0030] In some specific embodiments of the present application, the waste lithium batteries can be lithium batteries removed from a waste electric vehicle.

[0031] As a specific embodiment of the above-mentioned system of the present application, the coal-fired power plant comprises a coal-fired power plant boiler, a desulfurization and denitrification device, a steam turbine and a condenser, the flue gas outlet of the coal-fired power plant boiler is communicated with the desulfurization and denitrification device through a first outlet pipeline, the desulfurization and denitrification device is communicated with the carbon capture system through a flue gas discharge pipeline; the flue gas outlet of the coal-fired power plant boiler is also communicated with the gas inlet of the coal-fired power plant boiler through a second outlet pipeline in sequence via the steam turbine, the condenser and the pump.

[0032] The coal-fired power plant boiler, the desulfurization and denitrification device, the steam turbine and the condenser used by the coal-fired power plant are all conventional devices.

[0033] On the other hand, the present application also provides a method for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy, wherein the method is realized by using the above-mentioned system for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy, and the method comprises:

[0034] The flue gas of the coal-fired power plant after desulfurization and denitrification treatment enters the carbon capture system for carbon dioxide capture, and in the process of carbon dioxide capture, the electric energy generated by the wind power plant and / or the photoelectric plant and the heat energy collected by the solar heat collection system are used to provide electric energy and heat energy for the power-consuming equipment and heat-consuming equipment in the carbon capture system.

[0035] The captured carbon dioxide is reused or stored.

[0036] As a specific embodiment of the above-mentioned method of the present application, wherein, a part of the flue gas generated by the coal-fired power plant boiler enters the carbon capture system after passing through the desulfurization and denitrification device, and a part enters the steam turbine and then flows to the condenser, and then is compressed by the pump and flows back to the coal-fired power plant boiler to participate in the next process in the boiler.

[0037] As a specific embodiment of the above-mentioned method of the present application, wherein, when the carbon capture system is an MEA carbon capture system, the flue gas generated by the coal-fired power plant boiler enters the absorption tower of the carbon capture system after passing through the desulfurization and denitrification device, a part of the flue gas is discharged after being treated in the absorption tower, and a part is absorbed by the MEA solution in the absorption tower to form a rich liquid stream, which flows into the rich liquid pump, passes through the heat exchanger, is heated by the reboiler, and the MEA solution in the rich liquid is reprecipitated in the regeneration tower. The regenerated MEA solution can be reused by the lean liquid pump and cooled in the heat exchanger and then returned to the absorption tower, and the CO2 gas regenerated from the MEA solution can be utilized or sequestered.

[0038] As a specific embodiment of the above-mentioned method of the present application, wherein, the wind power plant generates electricity through the wind turbine, the electricity generated by the wind turbine is converted into electricity that can be utilized by passing through the PMSG, AC / DC and DC / AC, and enters the power grid for direct use by the carbon capture system.

[0039] As a specific embodiment of the above-mentioned method of the present application, wherein, the photovoltaic power plant inputs electricity into the controller for adjustment and then merges into the power grid for direct use by the carbon capture system.

[0040] As a specific embodiment of the above-mentioned method of the present application, wherein, the excess electricity generated after the wind power plant and / or photovoltaic power plant directly supply electricity to the carbon capture system is stored in the electricity storage device.

[0041] The present application utilizes the electricity generated by the wind power plant and / or photovoltaic power plant to directly supply electricity to the carbon capture system, which can significantly reduce the carbon emissions in the carbon capture system.

[0042] Compared with the prior art, the system and method for capturing CO2 of coal-fired power plants by utilizing solar heat and abandoned wind and light electricity provided by the present application can achieve the following beneficial technical effects:

[0043] The present application couples the new energy / clean energy, i.e. wind and light clean energy power generation system, with the traditional thermal power generation system, which can achieve low-carbon capture of CO2, increase the utilization rate of new energy power generation, reduce the frequency of deep peak shaving of thermal power generation, help solve the problem of high new energy power generation abandonment rate caused by insufficient deep peak shaving capacity of coal-fired power plants, reduce the impact of new energy power generation on the power grid, and avoid problems such as easy failure of the heating surface and economic decline of the power plant caused by frequent deep peak shaving of coal-fired power plants.

[0044] Compared with the traditional carbon capture method of steam extraction of a steam turbine, the application uses solar heat collection and abandoned wind and light electric energy to supply energy to the carbon capture system, can efficiently utilize some originally abandoned wind and light electric energy to supply energy to the carbon capture system, reduces the carbon emission and capture cost of the CO2 capture process of the coal-fired power plant itself, and realizes green carbon capture and economic carbon capture.

[0045] In summary, the system and method provided by the application will have good application prospects under the background of the double carbon target. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0047] Figure 1 The structural schematic diagram of the system for capturing CO2 of the coal-fired power plant by using solar heat collection and abandoned wind and light electric energy provided by the embodiment 1 of the application is shown.

[0048] Figure 2 The structural schematic diagram of the coal-fired power plant in the system provided by the embodiment 1 of the application is shown.

[0049] Figure 3 The structural schematic diagram of the MEA carbon capture system in the system provided by the embodiment 1 of the application is shown.

[0050] Figure 4 The structural schematic diagram of the wind power plant and the light power plant and the electric energy storage device in the system provided by the embodiment 1 of the application is shown.

[0051] Figure 5 The structural schematic diagram of the solar heat collection system in the system provided by the embodiment 1 of the application is shown.

[0052] MAIN DRAWING NUMBER EXPLANATION:

[0053] Figure 1 IN THE DRAWINGS:

[0054] I, coal-fired power plant;

[0055] II, MEA carbon capture system;

[0056] III, wind power plant and light power plant;

[0057] IV, solar heat collection system;

[0058] V, CO2 utilization or storage system;

[0059] Figure 2 In the process of:

[0060] 1. A coal-fired power plant boiler;

[0061] 2. A steam turbine;

[0062] 3. A desulfurization and denitrification device;

[0063] 4. A condenser;

[0064] 5. A pump;

[0065] Figure 3 In the process of:

[0066] 6. An absorption tower;

[0067] 7. A heat exchanger;

[0068] 8. A regeneration tower;

[0069] 9. A reboiler;

[0070] 10. A lean liquid pump;

[0071] 11. A rich liquid pump;

[0072] Figure 4 In the process of:

[0073] 12. A wind turbine;

[0074] 13. A PMSG;

[0075] 14. An AC / DC;

[0076] 15. A DC / AC;

[0077] 16. An electrical energy storage device;

[0078] 17. A controller;

[0079] 18. A solar panel;

[0080] Figure 5 In the process of:

[0081] 19. A boiler;

[0082] 20. An energy storage unit;

[0083] 21. A solar thermal collector;

[0084] 22. A first heat pump;

[0085] 23. A second heat pump;

[0086] 24. A compressor. DETAILED DESCRIPTION

[0087] In order to have a clearer understanding of the technical features, objectives and benefits of the present application, the technical solutions of the present application will be described in detail below in conjunction with the following specific embodiments, but it should not be understood as limiting the scope of the present application.

[0088] It should be noted that the terms "comprising" and any variations thereof in the present application and the above drawings are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0089] In addition, the terms "providing", "connecting" should be broadly understood. For example, "connecting" can be fixed connection, detachable connection, or integral structure; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, or internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood according to the specific circumstances by those skilled in the art.

[0090] Embodiment 1

[0091] The present embodiment provides a system for capturing CO2 of coal-fired power plant by solar heat collection and abandoned wind and light electric energy, the structural schematic diagram of which is as shown in Figure 1 It can be seen from Figure 1 that the system comprises:

[0092] a coal-fired power plant I, an MEA carbon capture system II, a wind power plant and a light power plant III, a solar heat collection system IV and a CO2 utilization or storage system V;

[0093] The structural schematic diagram of the coal-fired power plant I is as shown in Figure 2 It can be seen from Figure 2 that the coal-fired power plant I comprises a coal-fired power plant boiler 1, a desulfurization and denitrification device 3, a steam turbine 2 and a condenser 4, the flue gas outlet of the coal-fired power plant boiler 1 is communicated with the desulfurization and denitrification device 3 through a first outlet pipeline, the desulfurization and denitrification device 3 is communicated with the gas inlet of the absorption tower 6 in the MEA carbon capture system II through a flue gas discharge pipeline, so as to provide flue gas for the MEA carbon capture system II; the flue gas outlet of the coal-fired power plant boiler 1 is also communicated with the gas inlet of the coal-fired power plant boiler 1 through a second outlet pipeline in sequence via the steam turbine 2, the condenser 4 and the pump 5;

[0094] The structural schematic diagram of the MEA carbon capture system II is as shown in Figure 3 It can be seen from Figure 3As can be seen from the diagram, the MEA carbon capture system II includes an absorption tower 6, a regeneration tower 8, a heat exchanger 7, and a reboiler 9. The gas inlet of the absorption tower 6 is connected to the flue gas emission pipe of the coal-fired power plant I. The rich liquid outlet of the absorption tower 6 is connected to the rich liquid inlet of the regeneration tower 8 via a rich liquid pump 11 and a heat exchanger 7. The lean liquid outlet of the regeneration tower 8 is connected to the lean liquid inlet of the absorption tower 6 via a lean liquid pump 10 and a heat exchanger 7. The regeneration tower 8 is also connected to the reboiler 9 to heat the rich liquid in the regeneration tower 8.

[0095] The carbon dioxide gas outlet of the regeneration tower 8 in the MEA carbon capture system II is connected to the CO2 utilization or storage system V via a pipeline through the compressor 24; and the wind power plant and photovoltaic power plant III are used to provide power to the compressor 24.

[0096] The wind power plant and photovoltaic power plant III are used to provide electrical energy for the rich liquid pump 11, rich liquid pump 10 and reboiler 9, and the solar thermal collection system IV is used to provide thermal energy for the reboiler 9.

[0097] A simplified structural diagram of the wind power plant and photovoltaic plant III is shown below. Figure 4 As shown, from Figure 4 As can be seen from the above, the wind power plant and photovoltaic plant III include a wind power plant and a photovoltaic plant. The wind power plant includes a wind turbine 12, a PMSG 13, an AC / DC 14 and a DC / AC 15. The wind turbine 12 is connected to the power grid in sequence via the PMSG 13, AC / DC 14 and DC / AC 15.

[0098] The photovoltaic power plant includes solar panels 18 and a controller 17, wherein the solar panels 18 are electrically connected to the power grid via the controller 17;

[0099] A simplified structural diagram of the solar thermal collector system IV is shown below. Figure 5 As shown, from Figure 5 As can be seen from the diagram, the solar thermal system IV includes a solar collector 21, an energy storage unit 20, and a boiler 19. The solar collector 21 is connected to the energy storage unit 20 via a first heat pump 22, so that the heat energy collected by the solar collector 21 is stored in the energy storage unit 20 via the first heat pump 22. The energy storage unit 20 is connected to the boiler 19 via a second heat pump 23, so that the heat energy stored in the energy storage unit 20 is supplied to the boiler 19 via the second heat pump 23, thereby generating steam in the boiler 19 to provide heat energy for the reboiler 9 in the carbon capture system II, thereby driving the reboiler 9 to operate normally.

[0100] The solar collector 21 is a solar collector plate.

[0101] In the embodiment, the system further comprises an electric energy storage device 16 for storing the excess electric energy generated by the wind power plant and the photovoltaic power plant III; wherein the electric energy storage device is an electric energy storage device composed of waste lithium batteries.

[0102] Embodiment 2

[0103] The embodiment provides a method for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy, wherein the method is realized by using the system for capturing CO2 of a coal-fired power plant by using solar heat collection and abandoned wind and light electric energy provided in the embodiment 1, and the method comprises the following steps of:

[0104] The flue gas of the coal-fired power plant after desulfurization and denitrification treatment enters an MEA carbon capture system for carbon dioxide capture, and in the process of carbon dioxide capture, the electric energy generated by the wind power plant and the photovoltaic power plant and the heat energy collected by the solar heat collection system are used to provide electric energy and heat energy for the power-consuming equipment and heat-consuming equipment in the carbon capture system.

[0105] The captured carbon dioxide is compressed by a compressor and then enters a CO2 utilization or storage system for reuse or storage.

[0106] In the embodiment, part of the flue gas generated by the coal-fired power plant boiler enters the MEA carbon capture system after passing through the desulfurization and denitrification device, and part of the flue gas flows to the condenser after entering the steam turbine and then is compressed by the pump and flows back to the coal-fired power plant boiler to participate in the next process in the boiler.

[0107] In the embodiment, the flue gas generated by the coal-fired power plant boiler enters the absorption tower of the MEA carbon capture system after passing through the desulfurization and denitrification device, part of the flue gas is discharged after being treated in the absorption tower, and part of the flue gas is absorbed by the MEA solution in the absorption tower to form a rich liquid and flow into a rich liquid pump, is heated by a heat exchanger and a reboiler, and the MEA solution in the rich liquid is reprecipitated in the regeneration tower. The regenerated MEA solution can be reused by the lean liquid pump and cooling in the heat exchanger and then flowing back to the absorption tower, and the CO2 gas regenerated from the MEA solution can be utilized or stored.

[0108] In the embodiment, the wind power plant generates electricity by using the wind turbine, the electricity generated by the wind turbine is converted into usable electricity by PMSG, AC / DC and DC / AC, and then enters the power grid for direct use of the carbon capture system.

[0109] In the embodiment, the photovoltaic power plant inputs electricity into the controller for adjustment and then merges into the power grid for direct use of the carbon capture system.

[0110] In the embodiment, the excess electric energy generated by directly supplying the wind power plant and the photovoltaic power plant to the compressor and the rich liquid pump, the rich liquid pump and the reboiler in the carbon capture system is stored in the electric energy storage device.

[0111] The energy consumption and economy of the system for capturing CO2 of coal-fired power plants by using solar heat collection and abandoned wind and light electric energy provided in Embodiment 1 are analyzed by simulation calculation, mainly including three parts of MEA (organic amine) carbon capture system energy consumption simulation calculation, solar heat collection and heat supply economy evaluation and lithium battery energy storage cost accounting:

[0112] 1) Organic amine carbon capture system energy consumption simulation calculation:

[0113] In Embodiment 1 of the present application, the MEA carbon capture system uses the MEA carbon capture method to capture CO2, wherein the MEA carbon capture method is more suitable for a gas source with lower pressure, lower concentration, and smaller hydrogen sulfide partial pressure, and the MEA carbon capture method has simple process flow, small occupation, and less equipment investment, and is very suitable for a retrofit project.

[0114] Next, the MEA process flow is simulated and calculated by using the ELECNRTL model in Aspen Plus.

[0115] The MEA carbon capture method produces heat consumption on the regeneration tower and electric consumption on the pump during carbon capture, and if the steam and electricity produced by the coal-fired power plant itself are used to supply energy, the purpose of maximum energy saving and emission reduction cannot be achieved. In order to reduce carbon emissions in the carbon capture process to the greatest extent and increase the utilization rate of new energy generation, the abandoned wind and light electric energy is used to supply power to the equipment consuming electric energy in the MEA carbon capture system, and the abandoned wind and light electric energy is used to supplement the power supply (electric heating) of the reboiler when the solar heat supply is insufficient due to weather reasons.

[0116] The calculation of the MEA carbon capture system power consumption and carbon emissions is as follows:

[0117] In Embodiments 1-2 of the present application, the inlet flue gas temperature of the absorption tower in the MEA carbon capture system is 50℃, and the composition of the flue gas is shown in Table 1.

[0118] Table 1

[0119] Component [N2] O2 CO2 H2O mol% ratio 75.1 3.44 12.46 9.00

[0120] Take the mass flow of flue gas as 100000 kg / h as an example, the mass flow of CO2 is 18751.3 kg / h. The process parameters of the absorption tower in the MEA carbon capture system: the operating pressure is 1 atm, the inlet lean liquid temperature is 40℃; the absorption liquid uses MEA solution with a concentration of 30wt%, and the mass flow is 300000 kg / h. The process parameters of the regeneration tower in the MEA carbon capture system: the operating pressure is 2 atm, and the inlet rich liquid temperature is 102℃. The CO2 flow at the outlet of the absorption tower is: 303.6 kg / h, and the CO2 flow captured by the absorption tower is: 18447.7 kg / h. According to the above data, the carbon capture rate of the MEA carbon capture system is 98.4%.

[0121] In the system of capturing CO2 in coal-fired power plants by using solar heat collection and abandoned wind and light electric energy, the energy consumption is mainly in the regeneration tower and pump in the MEA carbon capture system, and the compressor for compressing and transporting CO2. Generally, the unit energy consumption of the regeneration process in the regeneration tower, the pumping process of the pump and the compression and transportation process of the compressor is 3-4 GJ / t CO2. According to the simulation results, the unit energy consumption of carbon capture is set to 4.068 GJ / t CO2 to facilitate the next step of design calculation.

[0122] Among them, the rich liquid pump in the pump is also one of the main components of energy consumption. The rich liquid pump is mainly used to pressurize the outlet rich liquid of the absorption tower to the pressure required by the desorption process. According to the simulation results, the operating energy consumption of the rich liquid pump is 11.59 kW, which corresponds to the capture amount of 18451 t / h of CO2.

[0123] After collecting relatively pure CO2, the part of CO2 needs to be compressed and transported. The electric quantity generated by the compression and transportation also needs to be calculated. The part of test data is also obtained by Aspen Plus simulation:

[0124] According to the simulation result data shown above, the CO2 pressure at the outlet of the regeneration tower is 2 atm. Generally, the storage and transportation pressure of CO2 is 100-150 atm. In this embodiment, six-stage compression-interstage cooling method is used for CO2 compression and storage. After interstage cooling to 35℃, gas-liquid separation is carried out, and then the gas enters the next stage of compression. The compression ratio of each stage is 2, and after six-stage compression, the gas pressure is 128 MPa, and the purity of CO2 product is greater than 99%.

[0125] Therefore, the total power consumption of the compressor is 2.2658 MW. According to the above results, the mass flow of CO2 released by the regeneration tower is 18451.2 kg / h, and the amount of CO2 obtained after compression and separation is 18377.1 kg / h, and the purity can reach 99.4% (mass fraction).

[0126] Suppose a 2x660MW ultra-supercritical coal-fired unit in Mengdong area as an example, its annual utilization hours is 6000h, annual power generation is 3960000000kW·h, take the coal heat value Q ar,net is 20.915MJ / kg, the power plant efficiency is 49.2%, the auxiliary power rate is 5.4%, the annual coal consumption is 504800t, the pollutant CO2 emission is 749.4g·(kW·h) -1 .

[0127] In the system provided by embodiment 1 of the present application, the calculation is carried out according to the CO2 capture rate of 85%. If the annual power generation is 3960000000kW·h, the CO2 emission is 749.400g·(kW·h) -1 , the annual CO2 emission is 2967624t, the annual CO2 capture is 2522480.4t; the rich liquid pump power is 1584.684kW, the annual energy consumption is 1.38x10 7 kW·h, the CO2 compression power is 309.799kW, the annual energy consumption is 2.71x10 6 kW·h.

[0128] In summary, the power of the MEA carbon capture system is about 1894.393kW, and the annual energy consumption is about 1.66x10 7 kW·h.

[0129] 2) Economic evaluation of solar heat collection and heating

[0130] In the system provided by embodiment 1 of the present application, the solar heat collection system can supply heat to the reboiler in the MEA carbon capture system to replace the traditional heat supply by using commercial steam or coal combustion.

[0131] 2.1 Traditional heat supply

[0132] a. Coal-fired heat supply

[0133] The regeneration temperature of MEA solution is generally about 120℃, and taking 0.2MPa, 132℃ saturated steam heat supply as an example, the enthalpy difference before and after steam heat supply is 2211kJ / kg.

[0134] The CO2 flow of flue gas at the outlet of the regeneration tower is: 18451.2kg / h, the regeneration tower energy consumption is: 20.85MW, and the unit CO2 capture energy consumption is:

[0135]

[0136] The heat demand of the reboiler in the MEA carbon capture system:

[0137] Q=q·M=10.261x10 6 GJ (2);

[0138] Wherein, M is the CO2 annual capture amount, which is 2522480.4t;

[0139] Then the annual steam consumption is:

[0140]

[0141] 0.0886 tons of standard coal per ton of steam:

[0142] M 煤 = 4.6413 x 10 6 × 0.0886 = 411224.80t (4) ;

[0143] It can be seen that if the coal-fired method is used to heat the reboiler in the MEA carbon capture system, a total of 41122.480 tons of standard coal is needed per year. If 0.74162 kg of carbon content is contained in each kg of standard coal, then 0.4 kg of standard coal will emit 0.272 kg of carbon, and the annual carbon emissions will be:

[0144]

[0145] If the coal-fired power plant uses raw coal for power generation, the current market price of raw coal is about 800 yuan / t, and the heat value is 0.7143 kg of standard coal per kg of raw coal, which is equivalent to a cost of about 2349.9 million yuan / year.

[0146] b, commercial steam

[0147] If commercial steam is used to heat the reboiler in the MEA carbon capture system, and the steam unit price is 180 yuan / ton of steam, the annual expenditure for heating the reboiler in the MEA carbon capture system is:

[0148] P1=4.6414x10 6 × 180 = 83545.2 million yuan (6) ;

[0149] 2.2 Solar thermal system instead of steam heating

[0150] Considering that the regeneration temperature of the MEA solution is 120℃, the inclined tracking groove type collector in the solar collector is selected for calculation in Example 1 of the present application. The heat collection efficiency of the solar collector is greatly affected by the environment, and changes with the change of the irradiation angle in different seasons and at different times. The average solar radiation data in each season is shown in Table 2.

[0151] Table 2

[0152] Season Spring Summer Autumn Winter Average solar radiation (W / m 2 )]]> 164.8 203.2 151.3 90.5 Heat collection efficiency 60％ 70％ 60％ 30％

[0153] The second row of data in Table 2 is the average solar heat radiation of a certain region in China. For example, in Inner Mongolia, the annual solar radiation is 1625-1855 kW, the annual sunshine hours are 3000-3200 h, and the average annual sunshine time under standard light is 4.45-5.08 h. Assuming that the heat obtained by the solar collector is used to heat water to become water vapor, and the water vapor is used to supply heat to the reboiler in the MEA carbon capture system, there is a 15% heat loss, and due to the small radiation in winter and low heat collection efficiency, steam needs to be used to supplement, so this place is taken as an example for estimation in autumn.

[0154] Taking 5 h of sunshine time as an example, the total heat required by the reboiler in a year is 10.261*10 6 GJ, and the heat required by the reboiler in the annual sunshine time is:

[0155]

[0156] The area of the solar collector is estimated to be:

[0157]

[0158] Where η1 is the heat efficiency of the heat transfer process, taken as 0.85, η2 is the efficiency of the solar collector, and I is the average solar heat radiation. Finally, the total area is:

[0159]

[0160] In addition, the investment and maintenance cost of the solar collector is shown in Table 3.

[0161] Table 3

[0162] Indicator Value Solar collector investment / $ per m -2 ]] 1900 Solar collector maintenance cost / $m -2 ]] 38

[0163] Note: The operation and maintenance cost is about 2% of the investment cost.

[0164] The cost required by the solar collector in the sunshine time is (x is the number of operation years):

[0165] P2=878601*1900+878601*1900*2%*x (10);

[0166] Converted to ten thousand yuan:

[0167] P2=166934.19+3338.68x (11);

[0168] In addition, the solar collection system requires an area of about 878601 square meters, which is equivalent to about 1317.9 mu of land. Assuming a land price of 8000 yuan / mu every 20 years, the total land price required by the solar collection system is estimated to be:

[0169] P3 = 8000 x 1317.9 = 1054.32 (RMB) (12);

[0170] Therefore, the total cost of using the solar heat collection system to replace steam heating during the sunshine time is (x is the number of operating years):

[0171] P4 = 1054.32 + 1982.91x (RMB) (13);

[0172] The cost of using pure steam heating is:

[0173] P5 = P1x = 83545.2x (14);

[0174] Let P5-P4 = 0, and x is almost 0.

[0175] Therefore, the investment recovery period of using the solar heat collection system to replace steam heating is less than one year. Such equipment usually operates for more than 20 years, so the economic benefit is good. Assuming that the equipment can operate for 20 years, only maintenance costs need to be paid, and the amount of steam or coal in those years can be completely saved. In summary, by comparing the coal consumption and the carbon emissions derived therefrom with the relevant data of the solar heating scheme, it can be found that since solar energy is a clean and low-carbon energy, the carbon emissions are very low, and therefore the use of the solar heat collection system for heating the reboiler in the MEA carbon capture system has achieved obvious energy-saving and emission-reducing effects.

[0176] Further, during the non-sunshine time, other heat sources need to be provided for the reboiler. Since the system of using solar heat collection and abandoned wind and light (photovoltaic) electric energy to capture CO2 in coal-fired power plants has relatively abundant electric energy generated by wind power plants and light (photovoltaic) power plants, it is considered to convert the stored electric energy into heat energy for the reboiler. The efficiency of converting electric energy into heat energy is calculated as 100%.

[0177] Among them, the heat energy required by the reboiler during the non-sunshine time is:

[0178]

[0179] Therefore, the electric energy required by the reboiler during the non-sunshine time is also 8120000 GJ, i.e. 2.256 x 10 6 kW·h.

[0180] 3) Cost accounting of lithium battery energy storage

[0181] The waste battery recycling market has not fully developed, and the price of waste batteries has great fluctuations. According to the data of mainstream manufacturers, the average delivery price of domestic power lithium batteries in the first half of 2019 is about 1.0 yuan / watt-hour. Lithium ion battery energy storage is a chemical energy storage technology with high energy conversion efficiency and high economic benefit. The maximum capacity of lithium ion battery is determined as follows: the required power of the MEA carbon capture system (including the compressor) in the non-sunshine time is used to deduce the required power of the lithium ion battery, and the cost of the lithium battery is calculated based on the power stored for five days. The energy consumption of the MEA carbon capture system per hour is 1894.4 kW, and the power stored in the lithium battery for five days is:

[0182] W = 1894.4KW × 5 × 24 = 227328KW·h (16);

[0183] Considering the purpose and cost calculation of the power stored in the lithium battery, the maximum capacity of the lithium battery is determined to be 230000 kilowatt-hours. The price of a degree of lithium ion battery energy storage is generally about 0.3 yuan, and the cost of a chemical energy storage power station is currently controlled at about 1000 yuan per kilowatt-hour. Considering that the waste lithium battery used in the present application is used, the price of the waste lithium battery is about 50% of the original price, that is, 500 yuan per kilowatt-hour.

[0184] The construction cost is:

[0185] P1 = 500 × 230000 = 11500 million yuan (17).

[0186] 4) Carbon emission reduction analysis and calculation of the system for capturing CO2 of coal-fired power plants by using solar heat collection and abandoned wind and light electric energy

[0187] For the coal-fired unit of the coal-fired power plant described in the present application, in the estimated full life cycle of 20 years, it is assumed that the traditional way is used, that is, the MEA carbon capture system is powered and heated by the coal-fired power plant, and the carbon emission calculation is as follows:

[0188] 4.1 The total CO2 emission generated by power supply is about:

[0189]

[0190] 4.2 The total CO2 emission generated by heating is about:

[0191] M2 = 279633 × 20 = 5.6 × 10 6 t (19);

[0192] Therefore, the total CO2 emission is about:

[0193] M3 = M1 + M2 = 3.26 x 10 7 + 5.6 x 10 6 = 3.82 x 10 7 t (20).

[0194] From the above experimental results, it can be analyzed that compared with the ordinary coal-fired power plant peak shaving, the system provided by the embodiment 1 of the present application has the following advantages in economy: the solar heat collection system is used to supply heat for the reboiler, which saves the steam cost or coal cost required by the existing reboiler heating mode; the wind power plant and the photovoltaic power plant are used to provide electric energy for the power consumption equipment in the carbon capture system, which saves the electricity cost required by the operation of the MEA carbon capture system; the advantages in emission reduction: in the embodiment of the present application, the solar heat collection and the abandoned wind and light electric energy are used to supply energy for the carbon capture system, which can efficiently utilize some originally abandoned wind and light electric energy to supply energy for the carbon capture system, reduces the carbon emission and capture cost of the CO2 capture process of the coal-fired power plant itself, and realizes green carbon capture and economic carbon capture. Through calculation, it is known that the system provided by the embodiment 1 of the present application can save about 34194.21 million yuan of cost for the coal-fired power plant within 20 years, and compared with the secondary carbon emission of the traditional coal-fired power plant due to carbon capture, the system provided by the embodiment 1 of the present application can reduce carbon emission by about 3.82 x 10 7 t.

[0195] The above is only a specific embodiment of the present application, and cannot limit the scope of the present application, so the replacement of equivalent components or equivalent changes and modifications made within the scope of the present application should still belong to the scope covered by the present patent. In addition, the technical features in the present application can be freely combined with each other, and the technical features can be freely combined with each other.

Claims

1. A system for capturing CO2 from coal-fired power plants using solar thermal and curtailed wind / solar electricity, characterized in that, The system comprises a coal-fired power plant, a carbon capture system, a solar heat collection system, a wind power plant and / or a photoelectric power plant, and a CO2 utilization or sequestration system, the flue gas discharge pipeline of the coal-fired power plant is communicated with the carbon capture system to provide flue gas for the carbon capture system, and the carbon capture system is further communicated with the CO2 utilization or sequestration system to utilize or sequester the captured CO2; The wind power plant and / or the photoelectric power plant are used to provide electric energy for the power-consuming equipment in the carbon capture system, and the solar heat collection system is used to provide thermal energy for the heat-consuming equipment in the carbon capture system; the wind power plant comprises a wind turbine, a PMSG, an AC / DC and a DC / AC, the wind turbine is electrically connected with a power grid via the PMSG, the AC / DC and the DC / AC in sequence, and the photoelectric power plant comprises a solar cell panel and a controller, the solar cell panel is electrically connected with the power grid via the controller; The solar heat collection system comprises a solar heat collector, an energy storage unit and a boiler, the solar heat collector is communicated with the energy storage unit through a first heat pump to store the thermal energy collected by the solar heat collector in the energy storage unit through the first heat pump, and the energy storage unit is communicated with the boiler through a second heat pump to supply the thermal energy stored in the energy storage unit to the boiler through the second heat pump, so that water vapor is generated in the boiler to provide thermal energy for the heat-consuming equipment in the carbon capture system; the energy storage unit is a lithium ion battery, and the solar heat collector is a solar heat collection panel; The carbon capture system is an MEA carbon capture system, the wind power plant and / or the photoelectric power plant are used to provide electric energy for the rich-liquid pump and the lean-liquid pump in the MEA carbon capture system, and the solar heat collection system is used to provide thermal energy for the reboiler in the MEA carbon capture system; the wind power plant and / or the photoelectric power plant are also used to provide electric energy for the reboiler in the MEA carbon capture system; the system further comprises a compressor, the carbon capture system is communicated with the CO2 utilization or sequestration system via the compressor through a pipeline, and the wind power plant and / or the photoelectric power plant are used to provide electric energy for the compressor; The system further comprises an electric energy storage device for storing the surplus electric energy generated by the wind power plant and / or the photoelectric power plant, and the electric energy storage device is an electric energy storage device composed of waste lithium batteries.

2. The system of claim 1, wherein, The MEA carbon capture system comprises an absorption tower, a regeneration tower, a heat exchanger and a reboiler, the gas inlet of the absorption tower is communicated with the flue gas discharge pipeline of the coal-fired power plant, the rich-liquid outlet of the absorption tower is communicated with the rich-liquid inlet of the regeneration tower via a rich-liquid pump and a heat exchanger, the lean-liquid outlet of the regeneration tower is communicated with the lean-liquid inlet of the absorption tower via a lean-liquid pump and a heat exchanger, and the regeneration tower is further communicated with the reboiler to heat the rich liquid in the regeneration tower.

3. The system of claim 1 or 2, wherein, The coal-fired power plant comprises a coal-fired power plant boiler, a desulfurization and denitrification device, a steam turbine and a condenser, a flue gas outlet of the coal-fired power plant boiler is communicated with the desulfurization and denitrification device through a first outlet pipeline, the desulfurization and denitrification device is communicated with the carbon capture system through a flue gas discharge pipeline; the flue gas outlet of the coal-fired power plant boiler is also communicated with a gas inlet of the coal-fired power plant boiler through a second outlet pipeline in sequence via the steam turbine, the condenser and a pump.

4. A method for capturing CO2 from coal-fired power plants using solar thermal and curtailed wind / solar electricity, characterized in that, The method is realized by using the system for capturing CO2 of the coal-fired power plant by using solar heat collection and abandoned wind and light electric energy according to any one of claims 1-3, which comprises: The flue gas of the coal-fired power plant after desulfurization and denitrification treatment enters the carbon capture system for carbon dioxide capture, in the process of carbon dioxide capture, the electric energy generated by the wind power plant and / or the light electric power plant and the heat energy collected by the solar heat collection system are used to provide electric energy and heat energy for the electric energy consuming equipment and the heat energy consuming equipment in the carbon capture system; The captured carbon dioxide is reused or stored.

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