Flue gas carbon capture system with waste heat recovery function and application method

Abstract

The invention relates to a flue gas carbon capture system with a waste heat recovery function and an application method. The flue gas carbon capture system with the waste heat recovery function comprises a washing tower, an absorption tower, a regeneration tower, a first evaporator, a compressor, temperature and pressure reduction equipment and a condenser, the first evaporator is provided with a first working medium inlet and a first working medium outlet, and the condenser is provided with a second working medium inlet and a second working medium outlet. The second working medium outlet, the temperature and pressure reduction equipment, the first working medium inlet, the first working medium outlet, the compressor and the second working medium inlet are sequentially communicated to form a working medium circulation loop, the working medium side of the condenser is a heat release side, and the absorbent side of the condenser is a heat absorption side. According to the flue gas carbon capture system with the waste heat recovery function, waste heat generated in the system can be recovered, the waste heat is used for the flue gas carbon capture system nearby, the use amount of cooling water is reduced, energy consumption is reduced, the problems of large public resource consumption and high operation cost are solved, and the flue gas carbon capture system has good flexibility and universality.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation, emission reduction, cost reduction and efficiency improvement, and in particular to a flue gas carbon capture system with waste heat recovery and an application method thereof. Background Art

[0002] Chemical absorption and desorption technology of carbon dioxide is a key carbon capture method. This technology achieves the capture and separation of carbon dioxide through chemical reactions between chemical absorbents and carbon dioxide, and reverses the reaction under specific conditions, thereby achieving the recycling and regeneration of the absorbent. In the related technology, the chemical absorption and desorption system of carbon dioxide has the following problems: high comprehensive energy consumption, especially in the desorption stage of the regeneration tower of carbon dioxide, which requires the provision of high-temperature thermal energy; low waste heat recovery rate, especially in the capture stage of the carbon dioxide absorption tower, the low-temperature reaction exotherm generated, most of the heat is taken away by cooling water; the cooling water consumption is large. There are also some methods in the related technology for recovering waste heat by coupling the previous and next processes, thereby improving the energy efficiency of the entire system, but the cost of this method is that the system becomes complicated, the control difficulty increases, and the flexibility and versatility are reduced. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention proposes a flue gas carbon capture system with waste heat recovery, which can recover the waste heat generated in the system and use the waste heat for the flue gas carbon capture system itself, thereby reducing the use of cooling water, reducing energy consumption, and reducing the problems of large consumption of public resources and high operating costs. At the same time, the arrangement of the first evaporator and the condenser has little impact on the related equipment of the washing tower, absorption tower and regeneration tower, and the installation and layout of the related pipelines are simple, so the control of the working fluid circulation loop is less affected by factors, simple to control, and has good flexibility and versatility.

[0005] An embodiment of the present invention provides an application method of a flue gas carbon capture system with waste heat recovery.

[0006] A flue gas carbon capture system with waste heat recovery according to an embodiment of the present invention comprises:

[0007] a scrubbing tower, the scrubbing tower having a first flue gas inlet, a first flue gas outlet, a scrubbing liquid inlet and a scrubbing liquid outlet;

[0008] an absorption tower, the absorption tower having a second flue gas inlet, a second flue gas outlet, a first lean liquid inlet and a first rich liquid outlet, the second flue gas inlet being in communication with the first flue gas outlet;

[0009] a regeneration tower, the regeneration tower having a first regeneration gas outlet, a first condensate inlet, a first rich liquid inlet, a first lean liquid outlet, a first absorbent inlet and a first absorbent outlet, the first lean liquid outlet being in communication with the first lean liquid inlet, and the first rich liquid outlet being in communication with the first rich liquid inlet;

[0010] a first evaporator, the first evaporator having a third smoke inlet, a third smoke outlet, a first working fluid inlet and a first working fluid outlet, the third smoke inlet being used to connect to a smoke source, and the third smoke outlet being communicated with the first smoke inlet;

[0011] Compressors and desuperheating and pressure reducing equipment; and,

[0012] A condenser, wherein the condenser has a second absorbent inlet, a second absorbent outlet, a second working fluid inlet and a second working fluid outlet, the second absorbent inlet is connected to the first absorbent outlet, the second absorbent outlet is connected to the first absorbent inlet, the second working fluid outlet, the temperature reduction and pressure reduction device, the first working fluid inlet, the first working fluid outlet, the compressor and the second working fluid inlet are connected in sequence to form a working fluid circulation loop, the working fluid side of the condenser is the heat release side, and the absorbent side of the condenser is the heat absorption side.

[0013] The flue gas carbon capture system with waste heat recovery in the embodiment of the present invention can recover the waste heat generated in the system and use the waste heat in the flue gas carbon capture system itself, thereby reducing the amount of cooling water used, reducing energy consumption, and reducing the problems of large consumption of public resources and high operating costs. At the same time, the arrangement of the first evaporator and the condenser has little impact on the related equipment of the washing tower, the absorption tower and the regeneration tower, and the installation and layout of the related pipelines are simple, so the control of the working medium circulation loop is less affected by factors, the control is simple, and it has good flexibility and versatility.

[0014] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a lean-rich liquid heat exchanger, the lean-rich liquid heat exchanger having a first heat absorption side inlet, a first heat absorption side outlet, a first heat release side inlet and a first heat release side outlet, the first heat absorption side inlet is connected to the first rich liquid outlet, the first heat absorption side outlet is connected to the first rich liquid inlet, the first heat release side inlet is connected to the first lean liquid outlet, and the first heat release side outlet is connected to the first lean liquid inlet.

[0015] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a second evaporator, the second evaporator having a second lean liquid inlet, a second lean liquid outlet, a third working fluid inlet and a third working fluid outlet, the second lean liquid inlet is connected to the first heat release side outlet, the second lean liquid outlet is connected to the first lean liquid inlet, the third working fluid inlet is connected to the outlet of the temperature reduction and pressure reduction device, and the third working fluid outlet is connected to the first working fluid inlet.

[0016] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a first regenerator, the first regenerator having a second heat absorption side inlet, a second heat absorption side outlet, a second heat release side inlet and a second heat release side outlet, the second heat absorption side inlet is connected to the first working fluid outlet, the second heat absorption side outlet is connected to the inlet of the compressor, the second heat release side inlet is connected to the second working fluid outlet, and the second heat release side outlet is connected to the inlet of the temperature reduction and pressure reduction device.

[0017] In some embodiments, the temperature and pressure reduction device of the flue gas carbon capture system with waste heat recovery is a throttle valve.

[0018] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a gas-liquid separator, which has a fourth regeneration gas inlet, a fourth regeneration gas outlet and a third condensate outlet, the fourth regeneration gas inlet is connected to the first regeneration gas outlet, and the third condensate outlet is connected to the first condensate inlet.

[0019] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a second regenerator, the second regenerator having a third heat absorption side inlet, a third heat absorption side outlet, a third heat release side inlet and a third heat release side outlet, the third heat release side inlet is connected to the first regeneration gas outlet, the third heat release side outlet is connected to the regeneration gas fourth inlet, the third heat absorption side inlet is connected to the third condensate outlet, and the third heat absorption side outlet is connected to the first condensate inlet.

[0020] In some embodiments, the flue gas carbon capture system with waste heat recovery further includes a regeneration gas cooler, the regeneration gas cooler having a fourth exothermic side inlet and a fourth exothermic side outlet, the fourth exothermic side inlet is connected to the third exothermic side outlet, and the third exothermic side outlet is connected to the fourth regeneration gas inlet.

[0021] In some embodiments, the flue gas carbon capture system with waste heat recovery further comprises a reboiler, wherein the inlet of the reboiler is connected to the outlet of the second absorbent, and the outlet of the reboiler is connected to the inlet of the first absorbent.

[0022] The application method of the flue gas carbon capture system with waste heat recovery of the embodiment of the present invention includes the following steps: introducing a working medium into the working medium circulation loop, the working medium enters the first evaporator to absorb heat and recover the heat energy of the flue gas, and then enters the compressor, is pressurized and heated by the compressor, and then enters the heat release side of the condenser to heat the absorbent entering the regeneration tower, and then enters the temperature reduction and pressure reduction equipment, and the working medium after temperature reduction and pressure reduction enters the first evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a flue gas carbon capture system with waste heat recovery according to an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of an example of a flue gas carbon capture system with waste heat recovery according to an embodiment of the present invention.

[0025] Reference numerals:

[0026] Flue gas carbon capture system 100;

[0027] Washing tower 1, first flue gas inlet 101, first flue gas outlet 102, washing liquid inlet 103, washing liquid outlet 104;

[0028] Absorption tower 2, second flue gas inlet 201, second flue gas outlet 202, first lean liquid inlet 203, first rich liquid outlet 204;

[0029] Regeneration tower 3, first regeneration gas outlet 301, first condensate inlet 302, first rich liquid inlet 303, first lean liquid outlet 304, first absorbent inlet 305, first absorbent outlet 306;

[0030] A first evaporator 4, a third flue gas inlet 401, a third flue gas outlet 402, a first working fluid inlet 403, and a first working fluid outlet 404;

[0031] Compressor 5, temperature and pressure reduction equipment 6;

[0032] Condenser 7, second absorbent inlet 701, second absorbent outlet 702, second working fluid inlet 703, second working fluid outlet 704;

[0033] First heat regenerator 8, second heat absorbing side inlet 801, second heat absorbing side outlet 802, second heat releasing side inlet 803, second heat releasing side outlet 804;

[0034] A second evaporator 9, a second lean liquid inlet 901, a second lean liquid outlet 902, a third working fluid inlet 903, and a third working fluid outlet 904;

[0035] Lean-rich liquid heat exchanger 10, first heat absorbing side inlet 1001, first heat absorbing side outlet 1002, first heat releasing side inlet 1003, first heat releasing side outlet 1004;

[0036] Booster fan 11;

[0037] The second regenerator 12 has a third heat absorbing side inlet 1201, a third heat absorbing side outlet 1202, a third heat releasing side inlet 1203, and a third heat releasing side outlet 1204;

[0038] Gas-liquid separator 13, regenerated gas cooler 14, reboiler 15, washing liquid cooler 16, lean liquid cooler 17. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0040] like Figure 1 As shown, the flue gas carbon capture system 100 with waste heat recovery according to an embodiment of the present invention includes a washing tower 1, an absorption tower 2, a regeneration tower 3, a first evaporator 4, a compressor 5, a temperature and pressure reduction device 6 and a condenser 7.

[0041] The scrubbing tower 1 has a first flue gas inlet 101, a first flue gas outlet 102, a scrubbing liquid inlet 103 and a scrubbing liquid outlet 104. The scrubbing liquid enters the scrubbing tower 1 from the scrubbing liquid inlet 103, and the flue gas enters the scrubbing tower 1 from the first flue gas inlet 101 for scrubbing. After the flue gas removes dust and soluble gas, it is discharged from the first flue gas outlet 102. After the scrubbing liquid scrubs the flue gas in the scrubbing tower 1, the liquid temperature rises and is discharged from the scrubbing liquid outlet 104. The scrubbing liquid is replaced and replenished regularly. The scrubbing tower 1 is gas-liquid countercurrent, with the flue gas flowing from bottom to top and the scrubbing liquid flowing from top to bottom.

[0042] The absorption tower 2 has a second flue gas inlet 201, a second flue gas outlet 202, a first lean liquid inlet 203 and a first rich liquid outlet 204, and the second flue gas inlet 201 is connected to the first flue gas outlet 102. The flue gas discharged through the first flue gas outlet 102 enters the absorption tower 2 through the second flue gas inlet 201, and the absorption tower 2 chemically absorbs carbon dioxide from the flue gas, and the purified flue gas is discharged from the second flue gas outlet 202. The purified flue gas is then processed according to on-site needs. The lean liquid flows into the absorption tower 2 from the first lean liquid inlet 203, and becomes a rich liquid after absorbing carbon dioxide in the absorption tower 2 and the temperature rises, and flows out from the first rich liquid outlet 204 at the bottom of the absorption tower 2. The absorption tower 2 is a gas-liquid countercurrent, with the flue gas flowing from bottom to top and the absorbent flowing from top to bottom.

[0043] The regeneration tower 3 has a first regeneration gas outlet 301, a first condensate inlet 302, a first rich liquid inlet 303, a first lean liquid outlet 304, a first absorbent inlet 305 and a first absorbent outlet 306. The first lean liquid outlet 304 is connected to the first lean liquid inlet 203, and the first rich liquid outlet 204 is connected to the first rich liquid inlet 303. The rich liquid flows into the regeneration tower 3 from the first rich liquid outlet 204 through the first rich liquid inlet 303, desorbs carbon dioxide in the regeneration tower 3 to become lean liquid, and flows out from the first lean liquid outlet 304 at the bottom of the regeneration tower 3 to the absorption tower 2, forming a cycle of lean and rich liquids. The desorbed carbon dioxide regeneration gas is discharged from the first regeneration gas outlet 301 at the top of the regeneration tower 3. The absorbent flows out from the first absorbent outlet 306. The regeneration tower 3 is a gas-liquid countercurrent, with the regeneration gas carbon dioxide flowing from bottom to top and the absorbent flowing from top to bottom.

[0044] The first evaporator 4 has a third flue gas inlet 401, a third flue gas outlet 402, a first working fluid inlet 403 and a first working fluid outlet 404. The third flue gas inlet 401 is used to connect the flue gas source. The third flue gas outlet 402 is connected to the first flue gas inlet 101. The flue gas flows through the heat release side of the first evaporator 4 and enters the washing tower 1 after the first evaporator 4 releases heat. The condenser 7 has a second absorbent inlet 701, a second absorbent outlet 702, a second working fluid inlet 703 and a second working fluid outlet 704. The second absorbent inlet 701 is connected to the first absorbent outlet 306, and the second absorbent outlet 702 is connected to the first absorbent inlet 305. The second working fluid outlet 704, the temperature reduction and pressure reduction device 6, the first working fluid inlet 403, the first working fluid outlet 404, the compressor 5 and the second working fluid inlet 703 are connected in sequence to form a working fluid circulation loop. The working fluid side of the condenser 7 is the heat release side, and the absorbent side of the condenser 7 is the heat absorption side. Then, during the working medium circulation process, it passes through the second working medium outlet 704 of the condenser 7, the inlet of the temperature reduction and pressure reduction device 6, the outlet of the temperature reduction and pressure reduction device 6, the first working medium inlet 403 of the first evaporator 4, the first working medium outlet 404, the inlet of the compressor 5, the outlet of the compressor 5 and the second working medium inlet 703 in sequence.

[0045] The application method of the flue gas carbon capture system 100 with waste heat recovery of the embodiment of the present invention includes the following steps: introducing a working medium into the working medium circulation loop, the working medium enters the first evaporator 4 to absorb heat and recover the heat energy of the flue gas, and then enters the compressor 5, is pressurized and heated by the compressor 5, and then enters the heat release side of the condenser 7 to heat the absorbent entering the regeneration tower 3, and then enters the temperature reduction and pressure reduction device 6, and the working medium after temperature reduction and pressure reduction enters the first evaporator 4.

[0046] When the working medium flows through the first evaporator 4 in the working medium circulation loop, it exchanges heat with the flue gas on the heat release side, absorbs the heat energy of the flue gas and then heats up to form a gaseous working medium; then it flows through the compressor 5, which pressurizes and heats up the gaseous working medium to form a high-temperature and high-pressure gaseous working medium, and then the high-temperature and high-pressure gaseous working medium enters the condenser 7. After the absorbent flows out from the first absorbent outlet 306, it enters the condenser 7 through the second absorbent inlet 701. In the condenser 7, the high-temperature and high-pressure gaseous working medium heats the absorbent once. After the absorbent is heated once by the condenser 7, it returns to the regeneration tower 3 from the first absorbent inlet 305. The gaseous working medium is condensed or cooled by the condenser 7 to form a high-temperature liquid working medium. The high-temperature liquid working medium enters the temperature reduction and pressure reduction device 6 for temperature reduction and pressure reduction, and then forms a low-temperature and low-pressure liquid working medium and enters the first evaporator 4 to absorb heat and vaporize and heat up again.

[0047] The flue gas carbon capture system 100 with waste heat recovery in the embodiment of the present invention is provided with a working medium circulation loop, and the working medium passes through the first evaporator 4 and the condenser 7. On the one hand, the waste heat of the flue gas is recovered, replacing the flue gas cooler of the washing tower 1 in the related technology, reducing the problem of cooling water. On the other hand, the recovered waste heat is pressurized and heated by the compressor 5 to heat the absorbent in the regeneration tower 3, thereby increasing the temperature of the absorbent entering the regeneration tower 3, thereby reducing the heat energy consumed to increase the temperature of the absorbent, reducing the problem of high energy consumption, and thus reducing the operating cost of the flue gas carbon capture system 100.

[0048] Therefore, the flue gas carbon capture system 100 with waste heat recovery of the embodiment of the present invention can recover the waste heat generated in the system 100, and use the waste heat for the flue gas carbon capture system 100 itself, thereby reducing the amount of cooling water used, reducing energy consumption, and reducing the problems of large consumption of public resources and high operating costs. At the same time, the arrangement of the first evaporator 4 and the condenser 7 has little impact on the related equipment of the washing tower 1, the absorption tower 2 and the regeneration tower 3, and the installation and layout of the related pipelines are simple, so the control of the working medium circulation loop is less affected by factors, the control is simple, and it has good flexibility and versatility.

[0049] In order to make the solution of the present application easier to understand, the temperature of the original flue gas entering the flue gas carbon capture system 100 is taken as an example of 75-85°C.

[0050] The flue gas carbon capture system 100 with waste heat recovery according to an embodiment of the present invention comprises a washing tower 1, an absorption tower 2, a regeneration tower 3, a first evaporator 4, a compressor 5, a condenser 7, a temperature reduction and pressure reduction device 6, a first regenerator 8, a second evaporator 9, a lean and rich liquid heat exchanger 10, a booster fan 11, a second regenerator 12, a gas-liquid separator 13, a regenerated gas cooler 14, a reboiler 15, a lean liquid cooler 17, a washing liquid cooler 16, a booster fan 11, a rich liquid pump, a lean liquid pump and an absorbent pump.

[0051] The scrubber 1 has a first flue gas inlet 101, a first flue gas outlet 102, a scrubbing liquid inlet 103 and a scrubbing liquid outlet 104. The booster fan 11 is arranged on the flue gas inlet side of the scrubber 1, the inlet of the booster fan 11 is connected to the original flue gas source, the outlet of the booster fan 11 is connected to the third flue gas inlet 401 of the first evaporator 4, and the third flue gas outlet 402 of the first evaporator 4 is connected to the first flue gas inlet 101. The original flue gas increases power through the booster fan 11, and then enters the scrubber 1 after passing through the cold zone of the first evaporator 4. The flue gas discharged from the first flue gas outlet 102 of the scrubber 1 has a temperature of about 40°C, and the scrubbing liquid discharged from the scrubbing liquid outlet 104 has a temperature of about 40-50°C.

[0052] The washing liquid cooler 16 has a sixth heat release side inlet and a sixth heat release side outlet, the inlet of the washing liquid pump is connected to the washing liquid outlet 104, the outlet of the washing liquid pump is connected to the sixth heat release side inlet, and the sixth heat release outlet is connected to the washing liquid outlet 104. The washing liquid is circulated. The heat absorption side of the washing liquid cooler 16 is connected to the external cooling water pipeline.

[0053] The absorption tower 2 has a second flue gas inlet 201, a second flue gas outlet 202, a first lean liquid inlet 203, a first rich liquid outlet 204, a desalted water replenishment port and an absorbent sewage outlet. The second flue gas inlet 201 is connected to the first flue gas outlet 102. The flue gas discharged through the first flue gas outlet 102 enters the absorption tower 2 through the second flue gas inlet 201. The purified flue gas discharged from the second flue gas outlet 202 has a temperature of 50-55°C, and the rich liquid discharged from the first rich liquid outlet 204 has a temperature of 50-55°C.

[0054] The regeneration tower 3 has a first regeneration gas outlet 301 , a first condensate inlet 302 , a first rich liquid inlet 303 , a first lean liquid outlet 304 , a first absorbent inlet 305 and a first absorbent outlet 306 . The first lean liquid outlet 304 is connected to the first lean liquid inlet 203 , and the first rich liquid outlet 204 is connected to the first rich liquid inlet 303 .

[0055] The lean and rich liquid heat exchanger 10 has a first heat absorbing side inlet 1001, a first heat absorbing side outlet 1002, a first heat releasing side inlet 1003 and a first heat releasing side outlet 1004. The first heat absorbing side inlet 1001 is connected to the first rich liquid outlet 204, the first heat absorbing side outlet 1002 is connected to the first rich liquid inlet 303, the first heat releasing side inlet 1003 is connected to the first lean liquid outlet 304, and the first heat releasing side outlet 1004 is connected to the first lean liquid inlet 203.

[0056] The rich liquid discharged from the absorption tower 2 flows through the heat absorption side of the lean-rich liquid heat exchanger 10, and the temperature rises to 100-105°C after absorbing heat. The rich liquid at 100-105°C enters the regeneration tower 3 from the first rich liquid inlet 303. The rich liquid decomposes carbon dioxide to become lean liquid, and the lean liquid is discharged from the first lean liquid outlet 304 at the bottom of the regeneration tower 3 at a temperature of 110-115°C. The high-temperature lean liquid enters the heat release side of the lean-rich liquid heat exchanger 10, and the temperature drops to 60-65°C after heat release, and then flows to the first lean liquid inlet 203 of the absorption tower 2. The desorbed carbon dioxide regeneration gas is discharged from the first regeneration gas outlet 301 at the top of the regeneration tower 3, and the temperature of the carbon dioxide regeneration gas is 98-102°C, 0.06Mpa. The absorbent of the regeneration tower 3 is discharged from the first absorbent outlet 306 at a temperature of about 112°C.

[0057] The lean and rich liquid heat exchanger 10 performs heat exchange on the high-temperature lean liquid generated by the regeneration tower 3 and the low-temperature rich liquid generated by the absorption tower 2, thereby realizing preheating and heating of the rich liquid and primary cooling of the lean liquid, thereby realizing the recovery of the waste heat of the lean liquid and heating of the rich liquid, thereby further utilizing the waste heat in the flue gas carbon capture system 100 itself, further reducing the use of cooling water, further reducing energy consumption, and further reducing the problems of large consumption of public resources and high operating costs.

[0058] Specifically, the rich liquid pump is connected to the first rich liquid outlet 204 of the absorption tower 2 and the first heat absorption side inlet 1001 of the lean-rich liquid heat exchanger 10, and the rich liquid pump pressurizes the rich liquid to provide circulation power for the rich liquid.

[0059] Specifically, the lean liquid pump connects the first heat release side outlet 1004 of the lean-rich liquid heat exchanger 10 and the first lean liquid inlet 203 of the absorption tower 2 , and the lean liquid pump pressurizes the lean liquid to provide circulation power for the lean liquid.

[0060] The condenser 7 has a second absorbent inlet 701, a second absorbent outlet 702, a second working fluid inlet 703 and a second working fluid outlet 704. The second absorbent inlet 701 is connected to the first absorbent outlet 306 of the regeneration tower 3, and the second absorbent outlet 702 is connected to the first absorbent inlet 305 of the regeneration tower 3. The working fluid side of the condenser 7 is the heat release side, and the absorbent side of the condenser 7 is the heat absorption side. The absorbent discharged from the regeneration tower 3 enters the heat absorption side of the condenser 7, exchanges heat with the gaseous working fluid on the heat release side of the condenser 7, and the temperature rises. The working fluid discharged from the heat release side of the condenser 7 is a liquid working fluid.

[0061] The inlet of the reboiler 15 is connected to the second absorbent outlet 702, the outlet of the reboiler 15 is connected to the inlet of the absorbent pump, and the outlet of the absorbent pump is connected to the first absorbent inlet 305 of the regeneration tower 3. The absorbent discharged from the second absorption outlet of the condenser 7 is heated once by the condenser 7, and then enters the reboiler 15 for secondary heating. The temperature of the absorbent after secondary heating is about 135°C, and then enters the regeneration tower 3. The absorbent pump provides power for the circulation of the absorbent and returns the heated absorbent to the regeneration tower 3.

[0062] Specifically, the reboiler 15 adopts a heating method such as steam heating, electric heating or combustion heating.

[0063] Specifically, the absorbent is selected according to the original flue gas conditions on site and product requirements, and the absorbent can be piperazine, alcohol amine absorbent or a compound absorbent.

[0064] The second evaporator 9, the first evaporator 4, the first regenerator 8, the compressor 5, the condenser 7 and the temperature reduction and pressure reduction device 6 are all located on the working medium circulation loop.

[0065] The second evaporator 9 has a second lean liquid inlet 901, a second lean liquid outlet 902, a third working fluid inlet 903 and a third working fluid outlet 904. The second lean liquid inlet 901 is connected to the first heat release side outlet 1004 of the lean-rich liquid heat exchanger 10, the second lean liquid outlet 902 is connected to the first lean liquid inlet 203, the third working fluid inlet 903 is connected to the outlet of the temperature reduction and pressure reduction device 6, and the third working fluid outlet 904 is connected to the first working fluid inlet 403.

[0066] The working fluid discharged from the heat release side of the condenser 7 is a liquid working fluid. After the liquid working fluid passes through the temperature reduction and pressure reduction device 6, the temperature and pressure are reduced to form a low-temperature liquid working fluid, and then enters the heat absorption side of the second evaporator 9 through the third working fluid inlet 903, exchanges heat with the lean liquid on the heat release side of the second evaporator 9, recovers the heat energy of the lean liquid, heats the low-temperature liquid working fluid once, increases the temperature of the working fluid, forms a gas-liquid mixed working fluid, and then is discharged from the third working fluid outlet 904.

[0067] The second evaporator 9 realizes further recovery of the waste heat of the lean liquid, thereby further using the waste heat nearby for the system 100 itself, further reducing the amount of cooling water used to cool the lean liquid, further reducing energy consumption, and further reducing the problems of large consumption of public resources and high operating costs.

[0068] The first evaporator 4 has a third flue gas inlet 401, a third flue gas outlet 402, a first working medium inlet 403 and a first working medium outlet 404. The third flue gas inlet 401 is connected to the outlet of the booster fan 11, and the third flue gas outlet 402 is connected to the first flue gas inlet 101 of the scrubber 1. The flue gas flows through the heat release side of the first evaporator 4, and the working medium discharged from the second evaporator 9 enters the heat absorption side of the first evaporator 4 through the first working medium inlet 403. The flue gas and the working medium exchange heat, and the cooled flue gas enters the scrubber 1, raising the temperature of the gas-liquid mixed working medium to form a pure gaseous working medium. The first evaporator 4 recovers the heat energy of the flue gas to perform secondary heating on the low-temperature gas-liquid mixed working medium.

[0069] The first regenerator 8 has a second heat absorption side inlet 801, a second heat absorption side outlet 802, a second heat release side inlet 803 and a second heat release side outlet 804. The second heat absorption side inlet 801 is connected to the first working fluid outlet 404, the second heat absorption side outlet 802 is connected to the inlet of the compressor 5, the second heat release side inlet 803 is connected to the second working fluid outlet 704, and the second heat release side outlet 804 is connected to the inlet of the temperature reduction and pressure reduction device 6.

[0070] The gas-liquid mixed working medium discharged from the first evaporator 4 enters the heat absorption side of the first regenerator 8, and the high-temperature liquid working medium discharged from the condenser 7 enters the heat release side of the first regenerator 8. The relatively high-temperature liquid working medium discharged from the condenser 7 further heats the gaseous working medium discharged from the first evaporator 4, thereby: ①, improving the superheat of the gaseous working medium, and then improving the thermal energy of the working medium gas entering the compressor 5, reducing the energy consumption of the compressor 5, and reducing the liquid hammer damage of the compressor 5, thereby further reducing the energy consumption of the system 100 and improving the energy efficiency of the flue gas carbon capture system 100, Further reduce the operating cost of the flue gas carbon capture system 100; ②, reduce the temperature difference of the high-temperature liquid working medium cooled by the cooling and decompression equipment 6, and also recover part of the heat of the high-temperature liquid working medium, reduce the working intensity of the cooling and decompression equipment 6, and reduce the waste of heat and pressure caused by the cooling and decompression of the high-temperature liquid working medium; ③ In this process, there is no change in the carbon dioxide absorption and analysis process, and the heat exchange of two working media with opposite flow directions is used to achieve the purpose of reducing energy consumption, which further demonstrates the flexibility and versatility of the flue gas carbon capture system 100.

[0071] Specifically, the temperature reduction and pressure reduction device 6 is a throttle valve, which has a simple structure and can achieve the temperature reduction and pressure reduction of the high-temperature liquid working medium required by the flue gas carbon capture system 100, and can also reduce the cost of the flue gas carbon capture system 100.

[0072] The second regenerator 12 has a third heat absorbing side inlet 1201, a third heat absorbing side outlet 1202, a third heat releasing side inlet 1203 and a third heat releasing side outlet 1204, and the third heat releasing side inlet 1203 is connected to the first regeneration gas outlet 301. The gas-liquid separator 13 has a fourth regeneration gas inlet, a fourth regeneration gas outlet and a third condensate outlet, the third heat releasing side outlet 1204 is connected to the fourth regeneration gas inlet, the third condensate outlet is connected to the third heat absorbing side inlet 1201, and the third heat absorbing side outlet 1202 is connected to the first condensate inlet 302.

[0073] The regeneration gas discharged from the first regeneration gas outlet 301 of the regeneration tower 3 enters the second regenerator 12 through the third heat release side inlet 1203, and then enters the gas-liquid separator 13, and generates a product gas with a purity of 95% at a temperature of about 40°C and a condensate with a temperature of about 45°C in the gas-liquid separator 13. The product gas is discharged from the fourth regeneration gas outlet and processed according to user needs. The condensate is discharged from the third condensate outlet and enters the second regenerator 12 through the third heat absorption side inlet 1201. In the second regenerator 12, the condensate exchanges heat with the regeneration gas to cool the regeneration gas and heat the condensate. Thereby, the temperature of the condensate entering the regeneration tower 3 is increased, and then the heating energy required to be provided by the reboiler 15 to ensure the temperature requirements in the regeneration tower 3 is reduced, thereby further reducing the energy consumption of the flue gas carbon capture system 100, further improving the energy efficiency of the flue gas carbon capture system 100, and further reducing the operating cost of the flue gas carbon capture system 100.

[0074] Specifically, the working fluid is R1233zdE, HFC245ca or HFC245fa.

[0075] The compressor 5 is a centrifugal compressor 5, a scroll compressor 5 or a screw compressor 5, and can be installed with one-stage compression, two-stage compression or three-stage compression, which can be selected according to site conditions and heating capacity requirements.

[0076] The regeneration gas cooler 14 has a fourth heat release side inlet and a fourth heat release side outlet, the fourth heat release side inlet is connected to the third heat release side outlet 1204, and the third heat release side outlet 1204 is connected to the fourth regeneration gas inlet. The regeneration gas cooler 14 is arranged between the heat release side of the second regenerator 12 and the gas-liquid separator 13 to perform secondary cooling on the regeneration gas.

[0077] The lean liquid cooler 17 has a fifth heat release side inlet and a fifth heat release side outlet, the fifth heat release side inlet is connected to the second lean liquid outlet 902 of the second evaporator 9, and the fifth heat release side outlet is connected to the first lean liquid inlet 203. The lean liquid cooler 17 cools the lean liquid three times, and the temperature of the lean liquid after cooling from the lean liquid cooler 17 is about 40°C.

[0078] Specifically, the second evaporator 9, the first evaporator 4, the washing liquid cooler 16, the lean liquid cooler 17, the lean-rich liquid heat exchanger 10, the first reheater 8, the second reheater 12 and the regenerated gas cooler 14 all use partition-type heat exchangers, such as plate heat exchangers, tube heat exchangers or heat pipe heat exchangers, etc., and a suitable structure and heat exchange area are selected according to site conditions and production requirements.

[0079] In the flue gas carbon capture system 100 of the embodiment of the present invention, the working fluid in the working fluid circulation loop first flows through the second evaporator 9, and then exchanges heat with the lean liquid located on the heat release side of the second evaporator 9, absorbs the heat energy of the lean liquid and then heats up to form a gas-liquid mixed working fluid; then flows through the first evaporator 4, and then exchanges heat with the flue gas located on the heat release side of the first evaporator 4, and then heats up to form a gaseous working fluid after absorbing the heat energy of the flue gas; then flows through the heat absorption side of the first regenerator 8, and then exchanges heat with the hot working fluid located on the heat release side of the first regenerator 8, and then absorbs the heat energy of the working fluid and increases the superheat. The compressor 5 pressurizes and heats the superheated gaseous working fluid to form a high-temperature and high-pressure gaseous working fluid, and then the high-temperature and high-pressure gaseous working fluid enters the condenser 7. After flowing out from the first absorbent outlet 306, the absorbent enters the condenser 7 through the second absorbent inlet 701. In the condenser 7, the high-temperature and high-pressure gaseous working medium heats the absorbent once. After being heated once by the condenser 7, the absorbent returns to the regeneration tower 3 from the first absorbent inlet 305. The gaseous working medium is condensed or cooled by the condenser 7 to form a high-temperature liquid working medium. The high-temperature liquid working medium first enters the first heat regenerator 8 on the heat release side to reduce the temperature, and then enters the temperature reduction and pressure reduction equipment 6 for further temperature reduction and pressure reduction, and then forms a low-temperature and low-pressure liquid working medium and enters the second evaporator 9 to absorb heat again and vaporize and heat up.

[0080] In the flue gas carbon capture system 100 of the embodiment of the present invention, the arrangement of the first evaporator 4, the second evaporator 9, the condenser 7 and the second regenerator 12 has little effect on the related equipment of the washing tower 1, the absorption tower 2 and the regeneration tower 3, and can be directly modified on the original traditional carbon capture system. The first evaporator 4, the second evaporator 9, the condenser 7 and the second regenerator 12 are added to the system, which not only reduces the modification range and cost to the greatest extent, but also through the working medium circulation loop formed by the condenser 7, the throttle valve, the second evaporator 9, the first evaporator 4, the first regenerator 8 and the compressor 5 and the second regenerator 12, the original flue gas, the lean liquid and the regenerated gas waste heat can be recycled, which can reduce the system energy consumption, water consumption and operating costs, and can also ensure the matching of heat supply and demand and temperature matching. In addition, the flue gas carbon capture system 100 of the embodiment of the present invention does not need to be combined with other processes, and has high flexibility and versatility.

[0081] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0082] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0083] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0085] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A flue gas carbon capture system (100) with waste heat recovery, characterized in that: include: A washing tower (1), wherein the washing tower (1) has a first flue gas inlet (101), a first flue gas outlet (102), a washing liquid inlet (103) and a washing liquid outlet (104); An absorption tower (2), the absorption tower (2) having a second flue gas inlet (201), a second flue gas outlet (202), a first lean liquid inlet (203) and a first rich liquid outlet (204), the second flue gas inlet (201) being in communication with the first flue gas outlet (102); A regeneration tower (3), the regeneration tower (3) having a first regeneration gas outlet (301), a first condensate inlet (302), a first rich liquid inlet (303), a first lean liquid outlet (304), a first absorbent inlet (305) and a first absorbent outlet (306), the first lean liquid outlet (304) being in communication with the first lean liquid inlet (203), and the first rich liquid outlet (204) being in communication with the first rich liquid inlet (303); A first evaporator (4), the first evaporator (4) having a third smoke inlet (401), a third smoke outlet (402), a first working fluid inlet (403) and a first working fluid outlet (404), the third smoke inlet (401) being used to connect to a smoke source, and the third smoke outlet (402) being in communication with the first smoke inlet (101); A compressor (5) and a temperature and pressure reduction device (6); and, A condenser (7), wherein the condenser (7) has a second absorbent inlet (701), a second absorbent outlet (702), a second working fluid inlet (703) and a second working fluid outlet (704); the second absorbent inlet (701) is connected to the first absorbent outlet (306); the second absorbent outlet (702) is connected to the first absorbent inlet (305); the second working fluid outlet (704), the temperature reduction and pressure reduction device (6), the first working fluid inlet (403), the first working fluid outlet (404), the compressor (5) and the second working fluid inlet (703) are connected in sequence to form a working fluid circulation loop; the working fluid side of the condenser (7) is a heat release side, and the absorbent side of the condenser (7) is a heat absorption side.

2. The flue gas carbon capture system (100) with waste heat recovery according to claim 1, characterized in that: The invention further comprises a lean-rich liquid heat exchanger (10), wherein the lean-rich liquid heat exchanger (10) has a first heat absorbing side inlet (1001), a first heat absorbing side outlet (1002), a first heat releasing side inlet (1003) and a first heat releasing side outlet (1004), wherein the first heat absorbing side inlet (1001) is connected to the first rich liquid outlet (204), the first heat absorbing side outlet (1002) is connected to the first rich liquid inlet (303), the first heat releasing side inlet (1003) is connected to the first lean liquid outlet (304), and the first heat releasing side outlet (1004) is connected to the first lean liquid inlet (203).

3. The flue gas carbon capture system (100) with waste heat recovery according to claim 2, characterized in that: The invention further comprises a second evaporator (9), wherein the second evaporator (9) has a second lean liquid inlet (901), a second lean liquid outlet (902), a third working fluid inlet (903) and a third working fluid outlet (904), wherein the second lean liquid inlet (901) is connected to the first heat release side outlet (1004), the second lean liquid outlet (902) is connected to the first lean liquid inlet (203), the third working fluid inlet (903) is connected to the outlet of the temperature reduction and pressure reduction device (6), and the third working fluid outlet (904) is connected to the first working fluid inlet (403).

4. The flue gas carbon capture system (100) with waste heat recovery according to claim 1, characterized in that: The invention further comprises that the first heat regenerator (8) has a second heat absorption side inlet (801), a second heat absorption side outlet (802), a second heat release side inlet (803) and a second heat release side outlet (804); the second heat absorption side inlet (801) is connected to the first working fluid outlet (404); the second heat absorption side outlet (802) is connected to the inlet of the compressor (5); the second heat release side inlet (803) is connected to the second working fluid outlet (704); and the second heat release side outlet (804) is connected to the inlet of the temperature reduction and pressure reduction device (6).

5. The flue gas carbon capture system (100) with waste heat recovery according to claim 1, characterized in that: The temperature and pressure reduction device (6) is a throttle valve.

6. The flue gas carbon capture system (100) with waste heat recovery according to claim 1, characterized in that: It further includes a gas-liquid separator (13), which has a fourth regeneration gas inlet, a fourth regeneration gas outlet and a third condensate outlet, the fourth regeneration gas inlet is connected to the first regeneration gas outlet (301), and the third condensate outlet is connected to the first condensate inlet (302).

7. The flue gas carbon capture system (100) with waste heat recovery according to claim 6, characterized in that: The invention further comprises a second regenerator (12), wherein the second regenerator (12) has a third heat absorbing side inlet (1201), a third heat absorbing side outlet (1202), a third heat releasing side inlet (1203) and a third heat releasing side outlet (1204), wherein the third heat releasing side inlet (1203) is connected to the first regeneration gas outlet (301), the third heat releasing side outlet (1204) is connected to the fourth regeneration gas inlet, the third heat absorbing side inlet (1201) is connected to the third condensate outlet, and the third heat absorbing side outlet (1202) is connected to the first condensate inlet (302).

8. The flue gas carbon capture system (100) with waste heat recovery according to claim 7, characterized in that: It further includes a regeneration gas cooler (14), the regeneration gas cooler (14) having a fourth heat release side inlet and a fourth heat release side outlet, the fourth heat release side inlet is connected to the third heat release side outlet (1204), and the third heat release side outlet (1204) is connected to the fourth regeneration gas inlet.

9. The flue gas carbon capture system (100) with waste heat recovery according to claim 1, characterized in that: It further comprises a reboiler (15), wherein the inlet of the reboiler (15) is connected to the second absorbent outlet (702), and the outlet of the reboiler (15) is connected to the first absorbent inlet (305).

10. An application method of a flue gas carbon capture system (100) with waste heat recovery, characterized in that: The flue gas carbon capture system (100) with waste heat recovery according to any one of claims 1 to 9 comprises the following steps: introducing a working medium into the working medium circulation loop, the working medium enters the first evaporator (4) to absorb heat and recover the heat energy of the flue gas, and then enters the compressor (5), is pressurized and heated by the compressor (5), and then enters the heat release side of the condenser (7) to heat the absorbent entering the regeneration tower (3), and then enters the temperature reduction and pressure reduction device (6), and the working medium after temperature reduction and pressure reduction enters the first evaporator (4).

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