System and method for recovering heat from gas turbine

Abstract

The invention relates to a system and method for recovering heat from a gas turbine. The system comprises a gas turbine, wherein generated first gas is conveyed to a gas outlet of the gas turbine; the heat recovery steam generator is used for receiving the first gas and generating steam by utilizing part of waste heat in the first gas, and second gas formed after the first gas passes through the heat recovery steam generator is conveyed to the gas outlet of the generator; the heat exchanger is used for receiving the second gas and the first liquid flow, a second liquid flow generated by heating the first liquid flow by the heat exchanger is conveyed to a liquid outlet of the exchanger, and a third gas generated by the heat exchanger is conveyed to a gas outlet of the exchanger; and the heat pump assembly receives the third gas and the second liquid flow, the first heat pump heats the second liquid flow to generate third liquid flow, the third liquid flow is conveyed to a liquid outlet of the first heat pump, and fourth gas generated by the first heat pump is conveyed to a gas outlet of the first heat pump. According to the system and method, waste heat can be extracted from the gas exhausted by the gas turbine, and the heat efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of thermal energy recovery, and in particular to a system and method for recovering heat from a gas turbine. Background Art

[0002] At present, the high-temperature gas generated by the gas turbine is reduced to about 110°C after passing through the heat recovery steam generator (HRSG for short). This part of the gas is directly discharged into the atmosphere, and the waste heat in the gas is wasted. Summary of the invention

[0003] In view of this, the present invention aims to provide a system and method for recovering heat from a gas turbine, so as to achieve the purpose of extracting waste heat from the gas exhausted by the gas turbine and improve thermal efficiency.

[0004] According to one aspect of the present invention, a system for recovering heat from a gas turbine is provided, in particular, the system comprises: a gas turbine, the gas turbine having a gas turbine outlet, wherein a first gas generated by the gas turbine is transported to the gas turbine outlet; a heat recovery steam generator, having a generator air inlet and a generator air outlet, wherein the generator air inlet is connected to the gas turbine outlet to receive the first gas, the heat recovery steam generator uses a portion of waste heat in the first gas to generate steam, and a second gas formed by the first gas after passing through the heat recovery steam generator is transported to the generator air outlet; a heat exchanger, having an exchanger air inlet, an exchanger liquid inlet, an exchanger air outlet and an exchanger liquid outlet, wherein the exchanger air inlet is connected to the generator air outlet The heat pump assembly comprises a heat pump assembly, comprising: a first heat pump assembly, wherein the first heat pump assembly comprises a first heat pump air inlet, a first heat pump liquid inlet, a first heat pump air outlet and a first heat pump liquid outlet, wherein the first heat pump air inlet is connected to the exchanger air outlet to receive the third gas, and the first heat pump liquid inlet is connected to the exchanger liquid outlet to receive the second liquid flow, the third liquid flow generated by the first heat pump heating the second liquid flow is delivered to the first heat pump liquid outlet, and the fourth gas generated by the first heat pump is delivered to the first heat pump air outlet.

[0005] In this way, the system of the present invention utilizes a heat pump component to extract waste heat from the exhaust gas of the gas turbine to heat a liquid flow (particularly a water flow), thereby obtaining a liquid flow with an increased temperature for use, such as for regional heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0006] In an exemplary embodiment, the heat pump assembly further includes a second heat pump having a second heat pump air inlet, a second heat pump liquid inlet, a second heat pump air outlet, and a second heat pump liquid outlet, wherein the second heat pump air inlet is connected to the first heat pump air outlet to receive the fourth gas, the second heat pump liquid inlet is connected to the first heat pump liquid outlet to receive the third liquid flow, the fourth liquid flow generated by the second heat pump heating the third liquid flow is transported to the second heat pump liquid outlet, and the fifth gas generated by the second heat pump is transported to the second heat pump air outlet.

[0007] In this way, the system of the present invention utilizes the first heat pump and the second heat pump connected in series in the heat pump assembly to extract more waste heat from the exhaust gas of the gas turbine to obtain a higher temperature liquid flow for use, such as for regional heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0008] In an exemplary embodiment, the heat pump assembly further includes a third heat pump, the third heat pump having a third heat pump air inlet, a third heat pump liquid inlet, a third heat pump air outlet and a third heat pump liquid outlet, wherein the third heat pump air inlet is connected to the second heat pump air outlet to receive the fifth gas, the third heat pump liquid inlet is connected to the second heat pump liquid outlet to receive the fourth liquid flow, the fifth liquid flow generated by the third heat pump heating the fourth liquid flow is transported to the third heat pump liquid outlet, and the sixth gas generated by the third heat pump is transported to the third heat pump air outlet.

[0009] In this way, the system of the present invention utilizes the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to extract more waste heat from the exhaust gas of the gas turbine to obtain a liquid flow with a further increased temperature for use, such as for regional heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0010] In an exemplary embodiment, the heat exchanger is configured to absorb a portion of waste heat of the second gas so that the temperature of the third gas is 20°C to 30°C lower than the temperature of the second gas; the first heat pump is configured to absorb a portion of waste heat of the third gas so that the temperature of the fourth gas is 15°C to 25°C lower than the temperature of the third gas; the second heat pump is configured to absorb a portion of waste heat of the fourth gas so that the temperature of the fifth gas is 15°C to 25°C lower than the temperature of the fourth gas; and the third heat pump is configured to absorb a portion of waste heat of the fifth gas so that the temperature of the sixth gas is 10°C to 20°C lower than the temperature of the fifth gas.

[0011] In this way, the system of the present invention utilizes the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to gradually extract more waste heat from the exhaust gas of the gas turbine to significantly improve the thermal efficiency.

[0012] In an exemplary embodiment, the temperature of the second gas is in the range of 105°C to 115°C; the temperature of the third gas is in the range of 80°C to 70°C; the temperature of the fourth gas is in the range of 60°C to 50°C; the temperature of the fifth gas is in the range of 40°C to 30°C; and the temperature of the sixth gas is in the range of 25°C to 15°C.

[0013] In this way, the system of the present invention utilizes the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to gradually extract more waste heat from the exhaust gas of the gas turbine to significantly improve the thermal efficiency.

[0014] In an exemplary embodiment, the temperature of the first liquid stream is in the range of 45°C to 55°C; the temperature of the second liquid stream is in the range of 65°C to 75°C; the temperature of the third liquid stream is in the range of 80°C to 90°C; the temperature of the fourth liquid stream is in the range of 95°C to 105°C; and the temperature of the fifth liquid stream is in the range of 110°C to 115°C.

[0015] In this way, the system of the present invention utilizes the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to gradually heat the first liquid flow with a temperature in the range of 45°C to 55°C to obtain the fifth liquid flow with a temperature in the range of 110°C to 115°C. This high-temperature liquid flow can be applied to many fields, including thermal energy storage, industrial heat exchange, etc., and is particularly suitable for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0016] In an exemplary embodiment, the heat pump assembly further includes a second heat pump having a second heat pump air inlet, a second heat pump liquid inlet, a second heat pump air outlet, and a second heat pump liquid outlet, wherein the second heat pump air inlet is connected to the exchanger air outlet to receive the third gas, the second heat pump liquid inlet is connected to the first heat pump liquid outlet to receive the third liquid flow, the fourth liquid flow generated by the second heat pump heating the third liquid flow is transported to the second heat pump liquid outlet, and the fifth gas generated by the second heat pump is transported to the second heat pump air outlet.

[0017] In this way, the system of the present invention utilizes both the first heat pump and the second heat pump in the heat pump assembly to directly extract waste heat from the gas from the exchanger outlet, which can heat the hot flow more quickly to obtain a higher temperature liquid flow for use, such as for district heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0018] In an exemplary embodiment, the heat pump assembly further comprises a third heat pump, the third heat pump having a third heat pump air inlet, a third heat pump liquid inlet, a third heat pump air outlet and a third heat pump liquid outlet, wherein the third heat pump air inlet is connected to the exchanger air outlet to receive the third gas or the third heat pump air inlet is connected to the second heat pump air outlet to receive the fifth gas, wherein the third heat pump liquid inlet is connected to the second heat pump liquid outlet to receive the fourth liquid flow, the fifth liquid flow generated by the third heat pump heating the fourth liquid flow is transported to the third heat pump liquid outlet, and the sixth gas generated by the third heat pump is transported to the third heat pump air outlet.

[0019] In this way, the system of the present invention utilizes two or three of the first heat pump, the second heat pump and the third heat pump in the heat pump assembly to directly extract waste heat from the gas from the exchanger outlet, which can heat the hot flow more quickly to obtain a higher temperature liquid flow for use, such as for district heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0020] In an exemplary embodiment, the first heat pump, the second heat pump and the third heat pump each include a compressor, a condenser, an expansion valve and an evaporator; wherein the output end of the compressor is connected to the input end of the condenser, the output end of the condenser is connected to the input end of the expansion valve, the output end of the expansion valve is connected to the input end of the evaporator, and the output end of the evaporator returns to the input end of the compressor to form a closed refrigerant circulation loop to achieve heat absorption and release; wherein the evaporator of the first heat pump exchanges heat with the third gas and the condenser of the first heat pump exchanges heat with the second liquid flow; wherein the evaporator of the second heat pump exchanges heat with the fourth gas and the condenser of the second heat pump exchanges heat with the third liquid flow; and wherein the evaporator of the third heat pump exchanges heat with the fifth gas and the condenser of the third heat pump exchanges heat with the fourth liquid flow.

[0021] In this way, the system of the present invention utilizes the reasonable configuration of the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to gradually extract more waste heat from the gas exhausted by the gas turbine to significantly improve the thermal efficiency.

[0022] According to another aspect of the present invention, a method for recovering heat from a gas turbine is provided, in particular, the method comprises the following steps: a first step: operating the gas turbine to generate a first gas; a second step: conveying the first gas to a heat recovery steam generator, the heat recovery steam generator utilizing a portion of waste heat in the first gas to generate steam, the first gas forming a second gas after passing through the heat recovery steam generator; a third step: conveying the second gas to a heat exchanger, and the heat exchanger utilizing a portion of waste heat in the second gas to heat a first liquid stream, so that the heat exchanger generates a second liquid stream having a higher temperature than the first liquid stream, and the heat exchanger generates a third gas having a lower temperature than the second gas; and a fourth step: conveying the third gas and the second liquid stream to a first heat pump of a heat pump assembly, and the first heat pump utilizing a portion of waste heat in the third gas to heat the second liquid stream, so that the first heat pump generates a third liquid stream having a higher temperature than the second liquid stream, and the first heat pump generates a fourth gas having a lower temperature than the third gas.

[0023] In this way, the method of the present invention utilizes a heat pump component to extract waste heat from the exhaust gas of a gas turbine to heat a liquid flow (particularly a water flow), thereby obtaining a liquid flow with an increased temperature for use, such as for regional heating, or for combined cycle power generation, which can significantly improve the overall efficiency of the power plant.

[0024] In an exemplary embodiment, the method further includes the following steps: a fifth step: transporting the fourth gas and the third liquid flow to a second heat pump of the heat pump assembly, and the second heat pump uses a portion of waste heat in the fourth gas to heat the third liquid flow, so that the second heat pump generates a fourth liquid flow with a higher temperature than the third liquid flow, and the second heat pump generates a fifth gas with a lower temperature than the fourth gas.

[0025] In this way, the method of the present invention utilizes the first heat pump and the second heat pump connected in series in the heat pump assembly to extract more waste heat from the exhaust gas of the gas turbine to obtain a higher temperature liquid flow for use, such as for regional heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0026] In an exemplary embodiment, the method further includes the following steps: a sixth step: transporting the fifth gas and the fourth liquid flow to a third heat pump of the heat pump assembly, and the third heat pump uses a portion of waste heat in the fifth gas to heat the fourth liquid flow, so that the third heat pump generates a fifth liquid flow with a higher temperature than the fourth liquid flow, and the third heat pump generates a sixth gas with a lower temperature than the fifth gas.

[0027] In this way, the method of the present invention utilizes the first heat pump, the second heat pump and the third heat pump connected in series in the heat pump assembly to extract more waste heat from the exhaust gas of the gas turbine to obtain a liquid flow with a further increased temperature for use, such as for regional heating, or for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0028] In summary, through the system and method for recovering heat from a gas turbine of the present invention, waste heat can be extracted from the gas exhausted by the gas turbine to obtain a liquid flow with increased temperature for use, such as for regional heating, or for combined cycle power generation. In particular, in the case of including multiple heat pumps arranged in series, the system and method of the present invention can gradually extract waste heat from the gas, so that the temperature of the liquid flow is gradually increased, which significantly improves the efficiency of energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the above and other features and advantages of the present invention will be more apparent to those skilled in the art. In the accompanying drawings:

[0030] Figure 1 is a schematic diagram of a system for recovering heat from a gas turbine according to an exemplary embodiment of the present invention.

[0031] Figure 2 is a schematic flow diagram of a method for recovering heat from a gas turbine according to an exemplary embodiment of the present invention.

[0032] Figure 3 is a schematic structural diagram of a heat pump of a system for recovering heat from a gas turbine according to an exemplary embodiment of the present invention.

[0033] Figure 4 is a schematic diagram of a system for recovering heat from a gas turbine according to another exemplary embodiment of the present invention. The reference numerals are as follows:

[0034] 10. Gas Turbine

[0035] 11. Gas turbine outlet

[0036] 101. First Gas

[0037] 20. Heat recovery steam generator

[0038] 201. Second Gas

[0039] 21. Generator air inlet

[0040] 22. Generator outlet

[0041] 30. Heat exchanger

[0042] 31. Exchanger air inlet

[0043] 32. Exchanger outlet

[0044] 33. Liquid inlet of exchanger

[0045] 34. Liquid outlet of exchanger

[0046] 300. First Liquid Flow

[0047] 301. The Third Gas

[0048] 302. Second Liquid Flow

[0049] 40. The first heat pump

[0050] 41. First heat pump air inlet

[0051] 42. First heat pump outlet

[0052] 43. First heat pump liquid inlet

[0053] 44. First heat pump outlet

[0054] 401, the fourth gas

[0055] 402, the third liquid flow

[0056] 50. Second heat pump

[0057] 51. Second heat pump air inlet

[0058] 52. Second heat pump outlet

[0059] 53. Second heat pump liquid inlet

[0060] 54. Second heat pump outlet

[0061] 501, The Fifth Gas

[0062] 502. Fourth Liquid Flow

[0063] 60. Third heat pump

[0064] 61. Third heat pump air inlet

[0065] 62. Third heat pump outlet

[0066] 63. Third heat pump liquid inlet

[0067] 64. Third heat pump outlet

[0068] 601, Sixth Gas

[0069] 602, Fifth Liquid Flow

[0070] 701. Compressor

[0071] 702. Condenser

[0072] 703, Expansion valve

[0073] 704, Evaporator

[0074] S1. First step

[0075] S2. Second step

[0076] S3. The third step

[0077] S4, the fourth step

[0078] S5. The fifth step

[0079] S6. Sixth step

[0080] A1. Relatively cold liquid flows into

[0081] A2. Relatively hot liquid discharge

[0082] B1. Relatively hot gas enters

[0083] B2. Relatively cold gas discharge DETAILED DESCRIPTION

[0084] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail with reference to the following embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The nouns and pronouns about people in this patent application are not limited to specific genders.

[0085] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well.

[0086] The present invention relates to the design of a system for improving the heating capacity of a combined cycle power plant by using heat pump technology. Figure 1, shows a schematic diagram of a system for recovering heat from a gas turbine according to an exemplary embodiment of the present invention. The system of the present invention mainly includes: a gas turbine 10, a heat recovery steam generator 20, a heat exchanger 30 and a heat pump assembly, wherein the heat pump assembly may include a first heat pump 40, a second heat pump 50 and a third heat pump 60. The first heat pump 40, the second heat pump 50 and the third heat pump 60 of the present invention can each be a 35 MW heat pump. The solution of the present invention can be applied to a 4000F combined cycle power plant. The solution of the present invention utilizes the waste heat output from the heat recovery steam generator to increase the heating capacity of the power plant by about 100 MW.

[0087] Reference Figure 1 The gas turbine has a gas turbine outlet 11 , wherein the first gas 101 generated by the gas turbine 10 is fed to the gas turbine outlet 11 .

[0088] Reference Figure 1 The heat recovery steam generator 20 has a generator air inlet 21 and a generator air outlet 22, wherein the generator air inlet 21 is connected to the gas turbine air outlet 11 to receive the first gas 101. The heat recovery steam generator 20 uses a part of the waste heat in the first gas 101 to generate steam, and the steam can be used, for example, to drive a steam turbine to generate electricity. The second gas 201 formed by the first gas 101 after passing through the heat recovery steam generator 20 is transported to the generator air outlet 22.

[0089] Reference Figure 1 The heat exchanger 30 has an exchanger air inlet 31, an exchanger liquid inlet 33, an exchanger air outlet 32 ​​and an exchanger liquid outlet 34, wherein the exchanger air inlet 31 is connected to the generator air outlet 22 to receive the second gas 201, and the exchanger liquid inlet 33 receives the first liquid flow 300, which is generally water. The second liquid flow 302 generated by the heat exchanger 30 heating the first liquid flow 300 is transported to the exchanger liquid outlet 34, and the third gas 301 generated by the heat exchanger 30 is transported to the exchanger air outlet 32.

[0090] Reference Figure 1 The first heat pump 40 has a first heat pump air inlet 41, a first heat pump liquid inlet 43, a first heat pump air outlet 42 and a first heat pump liquid outlet 44, wherein the first heat pump air inlet 41 is connected to the exchanger air outlet 32 ​​to receive the third gas 301, and the first heat pump liquid inlet 43 is connected to the exchanger liquid outlet 34 to receive the second liquid stream 302, the third liquid stream 402 generated by the first heat pump 40 heating the second liquid stream 302 is transported to the first heat pump liquid outlet 44, and the fourth gas 401 generated by the first heat pump 40 is transported to the first heat pump air outlet 42.

[0091] Reference Figure 1The second heat pump 50 has a second heat pump air inlet 51, a second heat pump liquid inlet 53, a second heat pump air outlet 52 and a second heat pump liquid outlet 54, wherein the second heat pump air inlet 51 is connected to the first heat pump air outlet 42 to receive the fourth gas 401, the second heat pump liquid inlet 53 is connected to the first heat pump liquid outlet 44 to receive the third liquid flow 402, the fourth liquid flow 502 generated by the second heat pump 50 heating the third liquid flow 402 is transported to the second heat pump liquid outlet 54, and the fifth gas 501 generated by the second heat pump 50 is transported to the second heat pump air outlet 52.

[0092] Reference Figure 1 The third heat pump 60 has a third heat pump air inlet 61, a third heat pump liquid inlet 63, a third heat pump air outlet 62 and a third heat pump liquid outlet 64, wherein the third heat pump air inlet 61 is connected to the second heat pump air outlet 52 to receive the fifth gas 501, the third heat pump liquid inlet 63 is connected to the second heat pump liquid outlet 54 to receive the fourth liquid stream 502, the fifth liquid stream 602 generated by the third heat pump 60 heating the fourth liquid stream 502 is transported to the third heat pump liquid outlet 64, and the sixth gas 601 generated by the third heat pump 60 is transported to the third heat pump air outlet 62, and the sixth gas 601 has a low temperature and can be directly discharged into the atmosphere.

[0093] The three heat pumps of the present invention can gradually increase the temperature of the first liquid flow, for example, by 45° C. or higher. The design capacity of the three heat pumps is 105 MW, and the COP (coefficient of performance) is equal to 4. The three heat pumps are connected in series. A heat storage tank can be used during the start-up and shutdown of the heat pumps.

[0094] The heat exchanger 30 is configured to absorb a portion of the waste heat of the second gas 201, so that the temperature of the third gas 301 is 20°C to 30°C lower than the temperature of the second gas 201; the first heat pump 40 is configured to absorb a portion of the waste heat of the third gas 301, so that the temperature of the fourth gas 401 is 15°C to 25°C lower than the temperature of the third gas 301; the second heat pump 50 is configured to absorb a portion of the waste heat of the fourth gas 401, so that the temperature of the fifth gas 501 is 15°C to 25°C lower than the temperature of the fourth gas 401; and the third heat pump 60 is configured to absorb a portion of the waste heat of the fifth gas 501, so that the temperature of the sixth gas 601 is 10°C to 20°C lower than the temperature of the fifth gas 501.

[0095] The temperature of the second gas 201 may be in the range of 105°C to 115°C; the temperature of the third gas 301 may be in the range of 80°C to 70°C; the temperature of the fourth gas 401 may be in the range of 60°C to 50°C; the temperature of the fifth gas 501 may be in the range of 40°C to 30°C; and the temperature of the sixth gas 601 may be in the range of 25°C to 15°C.

[0096] Particularly preferably, the temperature of the second gas 201 may be about 110° C.; the temperature of the third gas 301 may be about 75° C.; the temperature of the fourth gas 401 may be about 55° C.; the temperature of the fifth gas 501 may be about 35° C.; and the temperature of the sixth gas 601 may be about 20° C. By gradually cooling the second gas 201 in this manner, the waste heat in the second gas 201 may be extracted to the greatest extent, significantly improving thermal efficiency.

[0097] The temperature of the first liquid stream 300 can be in the range of 45°C to 55°C; the temperature of the second liquid stream 302 can be in the range of 65°C to 75°C; the temperature of the third liquid stream 402 can be in the range of 80°C to 90°C; the temperature of the fourth liquid stream 502 can be in the range of 95°C to 105°C; and the temperature of the fifth liquid stream 602 can be in the range of 110°C to 115°C.

[0098] Particularly preferably, the temperature of the first liquid stream 300 is about 50° C.; the temperature of the second liquid stream 302 is about 70° C.; the temperature of the third liquid stream 402 is about 85° C.; the temperature of the fourth liquid stream 502 is about 100° C.; and the temperature of the fifth liquid stream 602 is in the range of 110° C. to 115° C. By gradually heating the liquid stream in this way, the thermal efficiency can be significantly improved, and the high-temperature liquid stream finally obtained can be applied in many fields, including thermal energy storage, industrial heat exchange, etc., and is particularly suitable for combined cycle power generation, which can greatly improve the overall efficiency of the power plant.

[0099] Reference Figure 3 , the first heat pump 40, the second heat pump 50 and the third heat pump 60 each include a compressor 701, a condenser 702, an expansion valve 703 and an evaporator 704; wherein the output end of the compressor 701 is connected to the input end of the condenser 702, the output end of the condenser 702 is connected to the input end of the expansion valve 703, the output end of the expansion valve 703 is connected to the input end of the evaporator 704, and the output end of the evaporator 704 returns to the input end of the compressor 701, forming a closed refrigerant circulation loop to achieve heat absorption and release; wherein the evaporator of the first heat pump 40 is heat exchanged with the third gas 301 and the condenser of the first heat pump 40 is heat exchanged with the second liquid stream 302; wherein the evaporator of the second heat pump 50 is heat exchanged with the fourth gas 401 and the condenser of the second heat pump 50 is heat exchanged with the third liquid stream 402; and wherein the evaporator of the third heat pump 60 is heat exchanged with the fifth gas 501 and the condenser of the third heat pump 60 is heat exchanged with the fourth liquid stream 502. exist Figure 3 In the example, A1 represents a relatively cold liquid flow entering, A2 represents a relatively hot liquid flow exiting, B1 represents a relatively hot gas entering, and B2 represents a relatively cold gas exiting. It can be understood that, assuming Figure 3The heat pump shown in the figure is the first heat pump 40, the relatively cold liquid flow refers to the second liquid flow 302, the relatively hot liquid flow refers to the third liquid flow 402, the relatively hot gas refers to the third gas 301, and the relatively cold gas refers to the fourth gas 401. It can be understood that the solution of the present invention can adopt heat pumps of various structures in the prior art.

[0100] Reference Figure 2 The present invention provides a method for recovering heat from a gas turbine, which may include the following steps: a first step S1: operating a gas turbine 10 to generate a first gas 101; a second step S2: transporting the first gas 101 to a heat recovery steam generator 20, the heat recovery steam generator 20 using a portion of the waste heat in the first gas 101 to generate steam, and the first gas 101 forms a second gas 201 after passing through the heat recovery steam generator 20; a third step S3: transporting the second gas 201 to a heat exchanger 30, and the heat exchanger uses a portion of the second gas 201 to generate steam. The first liquid stream 300 is heated by the waste heat in the third gas 301, so that the heat exchanger produces a second liquid stream 302 with a higher temperature than the first liquid stream 300 and a third gas 301 with a lower temperature than the second gas 201; and a fourth step S4: the third gas 301 and the second liquid stream 302 are transported to the first heat pump 40 of the heat pump assembly, and the first heat pump 40 uses a part of the waste heat in the third gas 301 to heat the second liquid stream 302, so that the first heat pump 40 produces the third liquid stream 402 with a higher temperature than the second liquid stream 302 and the fourth gas 401 with a lower temperature than the third gas 301.

[0101] The method of the present invention may further include the following steps: Fifth step S5: transporting the fourth gas 401 and the third liquid stream 402 to the second heat pump 50 of the heat pump assembly, and the second heat pump 50 uses a portion of the waste heat in the fourth gas 401 to heat the third liquid stream 402, so that the second heat pump 50 generates a fourth liquid stream 502 with a higher temperature than the third liquid stream 402 and a fifth gas 501 with a lower temperature than the fourth gas 401.

[0102] The method of the present invention may further include the following steps: Sixth step S6: The fifth gas 501 and the fourth liquid stream 502 are transported to the third heat pump 60 of the heat pump assembly, and the third heat pump 60 uses a portion of the waste heat in the fifth gas 501 to heat the fourth liquid stream 502, so that the third heat pump 60 generates a fifth liquid stream 602 with a higher temperature than the fourth liquid stream 502, and the third heat pump 60 generates a sixth gas 601 with a lower temperature than the fifth gas 501.

[0103] Please refer to Figure 4, shows a schematic diagram of a system for recovering heat from a gas turbine according to another exemplary embodiment of the present invention. In this embodiment, the system mainly includes: a gas turbine 10, a heat recovery steam generator 20, a heat exchanger 30 and a heat pump assembly, wherein the heat pump assembly may include a first heat pump 40, a second heat pump 50 and a third heat pump 60. In this embodiment, the arrangement of the gas turbine 10, the heat recovery steam generator 20, the heat exchanger 30 and the first heat pump 40 is similar to Figure 1 The arrangements of the gas turbine 10, the heat recovery steam generator 20, the heat exchanger 30 and the first heat pump 40 in the embodiments are the same. Figure 4 The implementation method and Figure 1 The difference between the embodiments of the present invention mainly lies in the arrangement of the second heat pump 50 and the third heat pump 60. Figure 4 The implementation method and Figure 1 The differences in the implementation methods are described below.

[0104] exist Figure 4 In the embodiment of the present invention, the second heat pump 50 and the third heat pump 60 directly receive the third gas 301 from the exchanger outlet 32 ​​of the heat exchanger 30. Figure 4 In the embodiment, in terms of the way in which the first heat pump 40, the second heat pump 50 and the third heat pump 60 receive the intake air, the first heat pump 40, the second heat pump 50 and the third heat pump 60 can be regarded as being connected in parallel. Figure 1 In the solution, in terms of the way in which the first heat pump 40, the second heat pump 50 and the third heat pump 60 receive the intake air, the first heat pump 40, the second heat pump 50 and the third heat pump 60 can be regarded as being connected in series. Figure 4 In the scheme, the gas exhausted from the first heat pump 40, the second heat pump 50 and the third heat pump 60 can be reused or discharged to the atmosphere. Specifically, the gas exhausted from the first heat pump 40 can be transported to the second heat pump 50 or discharged to the atmosphere, and the gas exhausted from the second heat pump 50 can be transported to the third heat pump 60 or discharged to the atmosphere.

[0105] According to the present invention Figure 1 and Figure 4 Based on the teachings of the two illustrated embodiments, those skilled in the art may conceive of other embodiments, for example, two of the first heat pump 40, the second heat pump 50, and the third heat pump 60 directly receive the third gas 301 from the exchanger outlet 32 ​​of the heat exchanger 30. In addition, the number of heat pumps included in the heat pump assembly may be a value other than three heat pumps, for example, the heat pump assembly may include a fourth heat pump, a fifth heat pump, and the like. In terms of the air intake method of the multiple heat pumps, the multiple heat pumps may be connected in parallel or in series, or in a mixed connection method including parallel and series. In terms of the method of introducing liquid flow into the multiple heat pumps, Figure 1 and Figure 4The first liquid flow, the second liquid flow, the third liquid flow and the fourth liquid flow of the embodiment can be regarded as a series connection. Of course, as far as the method of introducing liquid flow of multiple heat pumps is concerned, multiple heat pumps can also be connected in parallel or in series or in a mixed connection method including parallel and series connection. It can be understood that these variant embodiments also fall within the protection scope of the present application.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for recovering heat from a gas turbine, characterized in that The system comprises: A gas turbine (10), the gas turbine having a gas turbine outlet (11), wherein a first gas (101) generated by the gas turbine is transported to the gas turbine outlet (11); A heat recovery steam generator (20) having a generator air inlet (21) and a generator air outlet (22), wherein the generator air inlet (21) is connected to the gas turbine air outlet (11) to receive the first gas (101), the heat recovery steam generator (20) uses a portion of the waste heat in the first gas (101) to generate steam, and the first gas (101) forms a second gas (201) after passing through the heat recovery steam generator (20), which is transported to the generator air outlet (22); a heat exchanger (30) having an exchanger gas inlet (31), an exchanger liquid inlet (33), an exchanger gas outlet (32) and an exchanger liquid outlet (34), wherein the exchanger gas inlet (31) is connected to the generator gas outlet (22) to receive the second gas (201), and the exchanger liquid inlet (33) receives the first liquid flow (300), the heat exchanger (30) heats the first liquid flow (300) to generate a second liquid flow (302) which is transported to the exchanger liquid outlet (34), and the third gas (301) generated by the heat exchanger (30) is transported to the exchanger gas outlet (32); and A heat pump assembly comprises at least a first heat pump (40), wherein the first heat pump (40) comprises a first heat pump air inlet (41), a first heat pump liquid inlet (43), a first heat pump air outlet (42) and a first heat pump liquid outlet (44), wherein the first heat pump air inlet (41) is connected to the exchanger air outlet (32) to receive the third gas (301), and the first heat pump liquid inlet (43) is connected to the exchanger liquid outlet (34) to receive the second liquid flow (302), the third liquid flow (402) generated by the first heat pump (40) heating the second liquid flow (302) is transported to the first heat pump liquid outlet (44), and the fourth gas (401) generated by the first heat pump (40) is transported to the first heat pump air outlet (42).

2. The system for recovering heat from a gas turbine according to claim 1, characterized in that The heat pump assembly further comprises a second heat pump (50), wherein the second heat pump (50) has a second heat pump air inlet (51), a second heat pump liquid inlet (53), a second heat pump air outlet (52) and a second heat pump liquid outlet (54). The second heat pump air inlet (51) is connected to the first heat pump air outlet (42) to receive the fourth gas (401); the second heat pump liquid inlet (53) is connected to the first heat pump liquid outlet (44) to receive the third liquid flow (402); the fourth liquid flow (502) generated by the second heat pump (50) heating the third liquid flow (402) is transported to the second heat pump liquid outlet (54); and the fifth gas (501) generated by the second heat pump (50) is transported to the second heat pump air outlet (52).

3. The system for recovering heat from a gas turbine according to claim 2, characterized in that The heat pump assembly further comprises a third heat pump (60), wherein the third heat pump (60) has a third heat pump air inlet (61), a third heat pump liquid inlet (63), a third heat pump air outlet (62) and a third heat pump liquid outlet (64). The third heat pump air inlet (61) is connected to the second heat pump air outlet (52) to receive the fifth gas (501); the third heat pump liquid inlet (63) is connected to the second heat pump liquid outlet (54) to receive the fourth liquid flow (502); the fifth liquid flow (602) generated by the third heat pump (60) heating the fourth liquid flow (502) is transported to the third heat pump liquid outlet (64); and the sixth gas (601) generated by the third heat pump (60) is transported to the third heat pump air outlet (62).

4. The system for recovering heat from a gas turbine according to claim 3, characterized in that The heat exchanger (30) is configured to absorb a portion of the waste heat of the second gas (201), so that the temperature of the third gas (301) is 20° C. to 30° C. lower than the temperature of the second gas (201); The first heat pump (40) is configured to absorb a portion of the waste heat of the third gas (301), so that the temperature of the fourth gas (401) is 15° C. to 25° C. lower than the temperature of the third gas (301); The second heat pump (50) is configured to absorb a portion of the waste heat of the fourth gas (401), so that the temperature of the fifth gas (501) is 15° C. to 25° C. lower than the temperature of the fourth gas (401); and The third heat pump (60) is configured to absorb a portion of the waste heat of the fifth gas (501), so that the temperature of the sixth gas (601) is 10°C to 20°C lower than the temperature of the fifth gas (501).

5. The system for recovering heat from a gas turbine according to claim 3, characterized in that The temperature of the second gas (201) is in the range of 105°C to 115°C; The temperature of the third gas (301) is in the range of 80°C to 70°C; The temperature of the fourth gas (401) is in the range of 60°C to 50°C; The temperature of the fifth gas (501) is in the range of 40°C to 30°C; and The temperature of the sixth gas (601) is in the range of 25°C to 15°C.

6. The system for recovering heat from a gas turbine according to claim 3, characterized in that The temperature of the first liquid stream (300) is in the range of 45°C to 55°C; The temperature of the second liquid stream (302) is in the range of 65°C to 75°C; The temperature of the third liquid stream (402) is in the range of 80°C to 90°C; The temperature of the fourth liquid stream (502) is in the range of 95°C to 105°C; and The temperature of the fifth liquid stream (602) is in the range of 110°C to 115°C.

7. The system for recovering heat from a gas turbine according to claim 1, characterized in that The heat pump assembly further comprises a second heat pump (50), wherein the second heat pump (50) has a second heat pump air inlet (51), a second heat pump liquid inlet (53), a second heat pump air outlet (52) and a second heat pump liquid outlet (54). The second heat pump air inlet (51) is connected to the exchanger air outlet (32) to receive the third gas (301); the second heat pump liquid inlet (53) is connected to the first heat pump liquid outlet (44) to receive the third liquid flow (402); the fourth liquid flow (502) generated by the second heat pump (50) heating the third liquid flow (402) is transported to the second heat pump liquid outlet (54); and the fifth gas (501) generated by the second heat pump (50) is transported to the second heat pump air outlet (52).

8. The system for recovering heat from a gas turbine according to claim 7, wherein the heat pump assembly further comprises a third heat pump (60), wherein the third heat pump (60) has a third heat pump air inlet (61), a third heat pump liquid inlet (63), a third heat pump air outlet (62) and a third heat pump liquid outlet (64), in, The third heat pump air inlet (61) is connected to the exchanger air outlet (32) to receive the third gas (301), or the third heat pump air inlet (61) is connected to the second heat pump air outlet (52) to receive the fifth gas (501), wherein the third heat pump liquid inlet (63) is connected to the second heat pump liquid outlet (54) to receive the fourth liquid flow (502), the fifth liquid flow (602) generated by the third heat pump (60) heating the fourth liquid flow (502) is transported to the third heat pump liquid outlet (64), and the sixth gas (601) generated by the third heat pump (60) is transported to the third heat pump air outlet (62).

9. The system for recovering heat from a gas turbine according to claim 3 or 8, characterized in that The first heat pump (40), the second heat pump (50) and the third heat pump (60) each include a compressor (701), a condenser (702), an expansion valve (703) and an evaporator (704); The output end of the compressor (701) is connected to the input end of the condenser (702), the output end of the condenser (702) is connected to the input end of the expansion valve (703), the output end of the expansion valve (703) is connected to the input end of the evaporator (704), and the output end of the evaporator (704) returns to the input end of the compressor (701), thereby forming a closed refrigerant circulation loop to achieve heat absorption and release; wherein the evaporator of the first heat pump (40) exchanges heat with the third gas (301) and the condenser of the first heat pump (40) exchanges heat with the second liquid flow (302); wherein the evaporator of the second heat pump (50) exchanges heat with the fourth gas (401) and the condenser of the second heat pump (50) exchanges heat with the third liquid stream (402); and The evaporator of the third heat pump (60) exchanges heat with the fifth gas (501), and the condenser of the third heat pump (60) exchanges heat with the fourth liquid flow (502).

10. A method for recovering heat from a gas turbine, characterized in that The method comprises the following steps: The first step (S1): operating the gas turbine (10) to generate a first gas (101); The second step (S2): transporting the first gas (101) to a heat recovery steam generator (20), wherein the heat recovery steam generator (20) generates steam using a portion of waste heat in the first gas (101), and the first gas (101) forms a second gas (201) after passing through the heat recovery steam generator (20); The third step (S3): the second gas (201) is transported to a heat exchanger (30), and the heat exchanger uses a portion of the waste heat in the second gas (201) to heat the first liquid stream (300), so that the heat exchanger (30) generates a second liquid stream (302) with a higher temperature than the first liquid stream (300), and the heat exchanger (30) generates a third gas (301) with a lower temperature than the second gas (201); and The fourth step (S4) is to transport the third gas (301) and the second liquid stream (302) to the first heat pump (40) of the heat pump assembly, and the first heat pump (40) uses a portion of the waste heat in the third gas (301) to heat the second liquid stream (302), so that the first heat pump (40) generates a third liquid stream (402) with a higher temperature than the second liquid stream (302), and the first heat pump (40) generates a fourth gas (401) with a lower temperature than the third gas (301).

11. The method for recovering heat from a gas turbine according to claim 10, characterized in that The method further comprises the steps of: The fifth step (S5) is to transport the fourth gas (401) and the third liquid stream (402) to the second heat pump (50) of the heat pump assembly, and the second heat pump (50) uses a portion of the waste heat in the fourth gas (401) to heat the third liquid stream (402), so that the second heat pump (50) generates a fourth liquid stream (502) with a higher temperature than the third liquid stream (402), and the second heat pump (50) generates a fifth gas (501) with a lower temperature than the fourth gas (401).

12. The method for recovering heat from a gas turbine according to claim 11, characterized in that The method further comprises the steps of: The sixth step (S6) is to transport the fifth gas (501) and the fourth liquid stream (502) to the third heat pump (60) of the heat pump assembly, and the third heat pump (60) uses a portion of the waste heat in the fifth gas (501) to heat the fourth liquid stream (502), so that the third heat pump (60) generates a fifth liquid stream (602) with a higher temperature than that of the fourth liquid stream (502), and the third heat pump (60) generates a sixth gas (601) with a lower temperature than that of the fifth gas (501).

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