Coal-fired power generation and energy storage coupling system

Abstract

The invention discloses a coal-fired power generation and energy storage coupling system, which belongs to the technical field of coal-fired power generation and comprises a coal-fired power generation unit and a Carnot battery energy storage unit. The coal-fired power generation unit comprises a coal-fired steam boiler, a steam turbine, a coal-fired unit power generator, a condenser, a water return pipeline and a water return heat exchanger; the Carnot battery energy storage unit comprises a heat pump circulation module, a middle heat storage module and a heat engine circulation module; the heat pump circulation module comprises a heat pump evaporator, a heat pump condenser, a compressor and a throttling valve. The heat engine circulation module comprises a heat engine evaporator, a heat engine condenser, a heat engine module expansion machine and a working medium pump; the middle heat storage module comprises a high-temperature tank and a low-temperature tank. Waste heat of the coal-fired power generation unit can be utilized through the Carnot battery energy storage unit, heat is converted into electric energy, combined heat and power generation is achieved, the energy utilization efficiency of the whole system is improved, multi-stage utilization of heat energy and mechanical energy can be achieved through heat pump circulation and heat engine circulation, and deep fusion of combined heat and power generation and energy storage can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired power generation, and in particular to a coal-fired power generation energy storage coupling system. Background Art

[0002] With the growth of global energy demand and the improvement of environmental protection requirements, coal-fired power generation units, as a traditional way of power production, are facing the dual pressures of improving energy efficiency and controlling carbon emissions. During the operation of traditional coal-fired power generation units, due to the limited energy utilization efficiency, there is often a large amount of waste heat and exhaust gas that cannot be fully utilized, resulting in energy waste. In this case, the development of a system that can utilize the waste heat of coal-fired power generation units has achieved a deep integration of cogeneration and energy storage, which can effectively improve the energy efficiency of the system. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a coal-fired power generation and energy storage coupling system, which utilizes the waste heat of the coal-fired power generation unit to provide a heat source for the heat pump cycle in the Carnot battery energy storage unit, and utilizes the condensed water of the coal-fired power generation unit to provide a cold source for the heat engine cycle in the Carnot battery energy storage unit, thereby effectively converting thermal energy into electrical energy, realizing cogeneration of heat and power, and improving the energy utilization efficiency of the overall system. Moreover, the combination of the heat pump cycle and the heat engine cycle of the Carnot battery can realize multi-level utilization of thermal energy and mechanical energy, and can achieve a deep integration of cogeneration of heat and power and energy storage.

[0004] To achieve the above-mentioned object, the present invention provides the following solutions: The present invention discloses a coal-fired power generation and energy storage coupling system, comprising a coal-fired power generation unit and a Carnot battery energy storage unit;

[0005] The coal-fired power generation unit comprises a coal-fired steam boiler, a steam turbine, a coal-fired unit generator, a condenser and a return water pipeline. A steam water pipe is provided in the coal-fired steam boiler. The steam port of the steam water pipe is connected to the steam inlet of the steam turbine. The output shaft of the steam turbine is connected to the input shaft of the coal-fired unit generator. The condensed gas inlet of the condenser is connected to the exhaust steam outlet of the steam turbine. The return water outlet of the condenser is connected to the return water port of the steam water pipe through the return water pipeline. The return water pipeline exchanges heat with the steam outlet of the steam turbine through a return water heat exchanger.

[0006] The Carnot battery energy storage unit includes a heat pump circulation module, an intermediate heat storage module and a heat engine circulation module; the heat pump circulation module includes a heat pump evaporator and a heat pump condenser, the heat source inlet of the heat pump evaporator is connected to the flue gas outlet of the coal-fired steam boiler, the heat transfer medium outlet of the heat pump evaporator is connected to the heat transfer medium inlet of the heat pump condenser through a compressor, and the heat transfer medium outlet of the heat pump condenser is connected to the heat transfer medium inlet of the heat pump evaporator through a throttle valve; the heat engine circulation module includes a heat engine evaporator and a heat engine condenser, and the heat transfer medium outlet of the heat engine evaporator is connected to the heat transfer medium inlet of the heat engine condenser through a heat engine module expander The heat transfer medium outlet of the heat engine condenser is connected to the heat transfer medium inlet of the heat engine evaporator through a working medium pump, the cold source inlet of the heat engine condenser is connected to the return water outlet of the condenser, and the cold source outlet of the heat engine condenser is connected to the return water port of the steam water pipe; the intermediate heat storage module includes a high-temperature tank and a low-temperature tank, the heat exchange medium inlet of the high-temperature tank is connected to the cold source outlet of the heat pump condenser, the heat exchange medium outlet of the high-temperature tank is connected to the heat source inlet of the heat engine evaporator, the heat exchange medium inlet of the low-temperature tank is connected to the heat source outlet of the heat engine evaporator, and the heat exchange medium outlet of the low-temperature tank is connected to the cold source inlet of the heat pump condenser.

[0007] Preferably, the steam turbine includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, the output shafts of the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are coaxially connected in sequence, and the output shaft of the low-pressure cylinder is coaxially connected to the input shaft of the coal-fired unit generator; the steam inlet of the high-pressure cylinder and the steam inlet of the medium-pressure cylinder are both connected to the steam port of the steam water pipe, the steam outlet of the medium-pressure cylinder is connected to the steam inlet of the low-pressure cylinder, the exhaust steam outlet is located on the low-pressure cylinder, and the steam outlet of the high-pressure cylinder, the steam outlet of the medium-pressure cylinder and the steam outlet of the low-pressure cylinder are connected to the return water heat exchanger.

[0008] Preferably, the coal-fired power generation unit includes a deaerator and a condensate pump, and the return water outlet of the condenser is connected to the return water inlet of the condensate pump; the return water heat exchanger includes a return water heat exchanger A, a return water heat exchanger B and a return water heat exchanger C, the return water inlet of the return water heat exchanger A is connected to the return water outlet of the condensate pump, the return water outlet of the return water heat exchanger A is connected to the return water inlet of the deaerator, the heat source inlet of the return water heat exchanger A is connected to the steam outlet of the low-pressure cylinder, and the heat source outlet of the return water heat exchanger A is connected to the return water inlet of the condenser; the return water The return water inlet of heat exchanger B is connected to the return water outlet of the deaerator, the return water outlet of the return water heat exchanger B is connected to the return water inlet of the return water heat exchanger C, the heat source inlet of the return water heat exchanger B is connected to the steam outlet of the intermediate pressure cylinder, the heat source outlet of the return water heat exchanger B is connected to the return water inlet of the deaerator, the return water outlet of the return water heat exchanger C is connected to the return water port of the steam water pipe, the heat source inlet of the return water heat exchanger C is connected to the steam outlet of the high pressure cylinder, and the heat source outlet of the return water heat exchanger C is connected to the heat source inlet of the return water heat exchanger B.

[0009] Preferably, it comprises a plurality of return water heat exchangers A arranged in sequence, the return water inlet of the return water heat exchanger A at the head end is connected with the return water outlet of the condensing water pump, the return water outlet of the return water heat exchanger A at the tail end is connected with the return water inlet of the deaerator, the return water inlet of the rear return water heat exchanger A is connected with the return water outlet of the front return water heat exchanger A, the heat source inlets of all the return water heat exchangers A are connected with the steam outlet of the low-pressure cylinder, the heat source inlet of the rear return water heat exchanger A is connected with the heat source outlet of the front return water heat exchanger A, and the heat source outlet of the return water heat exchanger A at the head end is connected with the return water inlet of the condenser.

[0010] Preferably, the steam outlet of the intermediate pressure cylinder is also connected to the return water inlet of the deaerator.

[0011] Preferably, the steam water pipe includes a No. 1 steam water pipe and a No. 2 steam water pipe, the steam port of the No. 1 steam water pipe is connected to the steam inlet of the high-pressure cylinder, the return water port of the No. 1 steam water pipe is connected to the return water outlet of the return water heat exchanger C, the steam port of the No. 2 steam water pipe is connected to the steam inlet of the medium-pressure cylinder, and the return water port of the No. 2 steam water pipe is connected to the steam outlet of the high-pressure cylinder.

[0012] Preferably, it comprises a plurality of return water heat exchangers C arranged in sequence, the return water inlet of the return water heat exchanger C at the head end is connected with the return water outlet of the deaerator, the return water outlet of the return water heat exchanger C at the end is connected with the return water port of the No. 1 steam water pipe, the return water inlet of the rear return water heat exchanger C is connected with the return water outlet of the front return water heat exchanger C, the heat source inlets of all the return water heat exchangers A are connected with the steam outlet of the high-pressure cylinder, the heat source outlet of the rear return water heat exchanger C is connected with the heat source inlet of the front return water heat exchanger C, and the heat source outlet of the return water heat exchanger C at the head end is connected with the return water inlet of the deaerator.

[0013] Preferably, the water return heat exchanger A is a low-pressure heat exchanger, and the water return heat exchanger B and the water return heat exchanger C are high-pressure heat exchangers.

[0014] Preferably, it includes a compressed air energy storage unit, which includes a No. 1 compressor, a No. 2 compressor, an air storage tank, a No. 1 expander, a No. 2 expander, an electric motor and an energy storage unit generator. The air outlet of the No. 1 compressor is connected to the air inlet of the No. 2 compressor through an energy storage heat exchanger A, the air outlet of the No. 2 compressor is connected to the air inlet of the air storage tank through an energy storage heat exchanger B, the air storage tank is connected to the air inlet of the No. 1 expander through an energy storage heat exchanger C, and the air outlet of the No. 1 expander is connected to the air inlet of the No. 1 expander. The air inlet of the No. 1 expander is connected to the air inlet through the energy storage heat exchanger D, and the air outlet of the No. 1 expander discharges air through the energy storage heat exchanger E. The power of the No. 1 compressor and the No. 2 compressor is provided by an electric motor. The No. 1 expander and the No. 2 expander drive the energy storage unit generator. The electric motor and the energy storage unit generator are both electrically connected to the power grid. The energy storage heat exchanger A, energy storage heat exchanger B, energy storage heat exchanger C, energy storage heat exchanger D and energy storage heat exchanger E are all connected to the return water pipeline.

[0015] Preferably, it comprises a plurality of energy storage heat exchangers A connected in series, a plurality of energy storage heat exchangers B connected in series, and a plurality of energy storage heat exchangers C connected in series.

[0016] Compared with the prior art, the present invention has achieved the following technical effects:

[0017] In the present invention, the waste heat of the coal-fired power generation unit is used to provide a heat source for the heat pump cycle in the Carnot battery energy storage unit, and the condensed water of the coal-fired power generation unit is used to provide a cold source for the heat engine cycle in the Carnot battery energy storage unit, so as to effectively convert heat energy into electrical energy, realize cogeneration of heat and power, and improve the energy utilization efficiency of the overall system. Moreover, the combination of the heat pump cycle and the heat engine cycle of the Carnot battery can realize the multi-level utilization of thermal energy and mechanical energy, and can realize the deep integration of cogeneration of heat and power and energy storage.

[0018] In addition to solving the above problems, other solutions of the present invention also achieve other technical effects:

[0019] In the present invention, a compressed air energy storage unit is coupled, and the compressed air energy storage unit can effectively utilize the waste heat of the coal-fired power generation unit, realizing the deep integration of cogeneration and energy storage. At the same time, the compressed air energy storage unit helps to solve the power fluctuation problem caused by the access of renewable energy to the power grid, improves the stability of the power grid, and significantly improves the peak-shaving capacity of the system. Moreover, the integration of the Carnot battery energy storage unit, the coal-fired power generation unit, and the compressed air energy storage unit realizes the deep integration of cogeneration and energy storage technology, greatly improving the energy utilization efficiency. By using the boiler flue gas of the coal-fired power plant to provide a high-temperature heat source for the Carnot battery, the boiler condensate absorbs heat for the organic cycle condenser, and the compressed air system is coupled with the steam extraction part of the turbine, this not only fully recovers the waste heat of the coal-fired power plant and reduces energy waste, but also improves the power generation efficiency of the compressed air energy storage and the Carnot battery, enhances the stability of the system when the penetration rate of renewable energy is increased, and helps to reduce carbon emissions and optimize the overall operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a structural schematic diagram of a coal-fired power generation and energy storage coupling system in an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a Carnot battery energy storage unit in an embodiment of the present invention;

[0023] Figure 3 is a schematic structural diagram of a coal-fired power generation unit in an embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the structure of a compressed air energy storage unit in an embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 1. Coal-fired power generation unit; 2. Carnot battery energy storage unit; 3. Compressed air energy storage unit;

[0027] 100. Coal-fired steam boiler; 101. High-pressure cylinder; 102. Medium-pressure cylinder; 103. Low-pressure cylinder; 104. Coal-fired unit generator; 105. Condenser; 106. Deaerator; 107. Condensate pump; 108. No. 1 return water heat exchanger A; 109. No. 2 return water heat exchanger A; 110. No. 3 return water heat exchanger A; 111. No. 4 return water heat exchanger A; 112. Return water heat exchanger B; 113. No. 1 return water heat exchanger C; 114. No. 2 return water heat exchanger C;

[0028] 200, heat pump evaporator; 201, heat pump condenser; 202, compressor; 203, throttle valve; 204, heat engine evaporator; 205, heat engine condenser; 206, heat engine module expander; 207, working fluid pump; 208, high temperature tank; 209, low temperature tank;

[0029] 300. Compressor No. 1; 301. Compressor No. 2; 302. Air storage tank; 303. Expander No. 1; 304. Expander No. 2; 305. Electric motor; 306. Energy storage unit generator; 307. Energy storage heat exchanger No. 1 A; 308. Energy storage heat exchanger No. 2 A; 309. Energy storage heat exchanger No. 1 B; 310. Energy storage heat exchanger No. 2 B; 311. Energy storage heat exchanger No. 1 C; 312. Energy storage heat exchanger No. 2 C. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] This embodiment provides a coal-fired power generation and energy storage coupling system, such as Figures 1 to 4 As shown, it includes a coal-fired power generation unit 1 and a Carnot battery energy storage unit 2;

[0032] The coal-fired power generation unit 1 includes a coal-fired steam boiler 100, a steam turbine, a coal-fired unit generator 104, a condenser 105, and a return water pipeline. A steam water pipe is provided in the coal-fired steam boiler 100, and the steam port of the steam water pipe is connected to the steam inlet of the steam turbine. The output shaft of the steam turbine is connected to the input shaft of the coal-fired unit generator 104. The condensed gas inlet of the condenser 105 is connected to the exhaust steam outlet of the steam turbine, and the return water outlet of the condenser 105 is connected to the return water port of the steam water pipe through the return water pipeline, and the return water pipeline exchanges heat with the steam outlet of the steam turbine through the return water heat exchanger.

[0033] The Carnot battery energy storage unit 2 includes a heat pump circulation module, an intermediate heat storage module and a heat engine circulation module. The heat pump circulation module includes a heat pump evaporator 200, a heat pump condenser 201, a compressor 202 and a throttle valve 203. The heat source inlet of the heat pump evaporator 200 is connected to the flue gas outlet of the coal-fired steam boiler 100. The heat transfer medium outlet of the heat pump evaporator 200 is connected to the heat transfer medium inlet of the heat pump condenser 201 through the compressor 202. The heat transfer medium outlet of the heat pump condenser 201 is connected to the heat transfer medium inlet of the heat pump evaporator 200 through the throttle valve 203. The heat engine cycle in the heat engine circulation module is also called the Organic Rankine Cycle (ORC), which includes a heat engine evaporator 204, a heat engine condenser 205, a heat engine module expander 206 and a working medium pump 207. The heat transfer medium outlet of the heat engine evaporator 204 is connected to the heat transfer medium inlet of the heat engine condenser 205 through the heat engine module expander 206, and the heat transfer medium outlet of the heat engine condenser 205 is connected to the heat transfer medium inlet of the heat engine evaporator 204 through the working medium pump 207. The cold source inlet of the heat engine condenser 205 is connected to the return water outlet of the condenser 105, and the cold source outlet of the heat engine condenser 205 is connected to the return water port of the steam water pipe. The intermediate heat storage module includes a high temperature tank 208 and a low temperature tank 209, the heat exchange medium inlet of the high temperature tank 208 is connected to the cold source outlet of the heat pump condenser 201, and the heat exchange medium outlet of the high temperature tank 208 is connected to the heat source inlet of the heat engine evaporator 204. The heat exchange medium inlet of the low temperature tank 209 is connected to the heat source outlet of the heat engine evaporator 204. The heat exchange medium outlet of the low temperature tank 209 is connected to the cold source inlet of the heat pump condenser 201.

[0034] Working principle:

[0035] Working process of coal-fired power generation unit 1: During the working process of the coal-fired steam boiler 100, the water in the steam water pipe will be heated to form high-temperature steam. After the high-temperature steam enters the steam turbine through the steam port of the steam water pipe, it can drive the output shaft of the steam turbine to rotate, and then drive the input shaft of the coal-fired unit generator 104 to rotate, driving the coal-fired unit generator 104 to generate electricity. After the coal-fired unit generator 104 is electrically connected to the power grid, it can provide electricity to the power grid. During the working process of the steam turbine, the steam will pass into the condenser 105 through the exhaust steam outlet of the steam turbine, and then condensed into water by the condenser 105. During the process of the condensed water flowing to the steam water pipe of the coal-fired steam boiler 100 through the return water pipeline, it will be heated by the return water heat exchanger, thereby accelerating the subsequent evaporation efficiency.

[0036] Working process of Carnot battery energy storage unit 2: The low-temperature flue gas generated by the coal-fired steam boiler 100 will enter the heat pump evaporator 200 from the flue gas outlet, heat and evaporate the liquid heat transfer medium in the heat pump evaporator 200 to form a gaseous heat transfer medium, and the gaseous heat transfer medium will flow into the heat pump condenser 201 after being compressed by the compressor 202, and exchange heat with the heat exchange medium in the gaseous heat transfer medium low-temperature tank 209 to condense into a liquid heat transfer medium, and the liquid heat transfer medium will enter the heat pump evaporator 200 for the next cycle after being decompressed by the throttle valve 203. The heat exchange medium after heat exchange enters the high-temperature tank 208 to store heat for use in the subsequent heat engine cycle (energy release stage). The heat exchange medium (water can be used) in the high temperature tank 208 can exchange heat with the liquid heat transfer medium in the heat pump evaporator 200, heating the liquid heat transfer medium to a gaseous heat transfer medium. The cooled heat exchange medium enters the low temperature tank 209 for storage, and the heat exchange medium in the low temperature tank 209 can cool the gaseous heat transfer medium in the heat pump condenser 201 to promote its condensation into a liquid heat transfer medium. The gaseous heat transfer medium in the heat pump evaporator 200 passes through the heat engine module expander 206, and the output shaft of the heat engine module expander 206 is connected to the input shaft of the heat engine module generator, so that power generation can be performed. The gaseous heat transfer medium output by the heat engine module expander 206 enters the heat engine condenser 205, exchanges heat with the condensed water provided by the condenser 105 of the coal-fired power generation unit 1, and the gaseous heat transfer medium condenses into a liquid heat transfer medium, which is passed back to the heat engine evaporator 204 through the medium pump 207 for the next cycle. The working fluid used in the Organic Rankine Cycle (ORC) is a low-boiling-point organic working fluid.

[0037] The Carnot battery is a thermoelectric conversion device driven by temperature difference, which is particularly suitable for the recovery and reuse of medium and low temperature heat sources. The waste heat of the coal-fired power generation unit 1 is used to provide a heat source for the heat pump cycle in the Carnot battery energy storage unit 2, and the condensed water of the coal-fired power generation unit 1 is used to provide a cold source for the heat engine cycle in the Carnot battery energy storage unit 2, so as to effectively convert heat energy into electrical energy, realize cogeneration of heat and power, and improve the energy utilization efficiency of the overall system. Moreover, the combination of the heat pump cycle and the heat engine cycle of the Carnot battery can realize the multi-level utilization of thermal energy and mechanical energy, and can realize the deep integration of cogeneration of heat and power and energy storage.

[0038] In one embodiment, if Figures 1 to 4As shown, the steam turbine includes a high-pressure cylinder 101, an intermediate-pressure cylinder 102 and a low-pressure cylinder 103. The output shafts of the high-pressure cylinder 101, the intermediate-pressure cylinder 102 and the low-pressure cylinder 103 are coaxially connected in sequence. The output shaft of the low-pressure cylinder 103 is coaxially connected to the input shaft of the coal-fired unit generator 104. The steam inlet of the high-pressure cylinder 101 and the steam inlet of the intermediate-pressure cylinder 102 are both connected to the steam port of the steam water pipe. The steam outlet of the intermediate-pressure cylinder 102 is connected to the steam inlet of the low-pressure cylinder 103, and the exhaust steam outlet is located on the low-pressure cylinder 103. The steam outlet of the high-pressure cylinder 101, the steam outlet of the intermediate-pressure cylinder 102, and the steam outlet of the low-pressure cylinder 103 are connected to the return water heat exchanger.

[0039] Working principle:

[0040] The high-temperature steam of the coal-fired steam boiler 100 will enter the high-pressure cylinder 101 and the medium-pressure cylinder 102 respectively, and the high-temperature steam in the medium-pressure cylinder 102 will be passed into the low-pressure cylinder 103. The high-pressure cylinder 101, the medium-pressure cylinder 102 and the low-pressure cylinder 103 will drive their respective output shafts to rotate under the steam drive, and the output shaft of the low-pressure cylinder 103 drives the input shaft of the coal-fired unit generator 104 to rotate to generate electricity. The exhaust steam (steam at the end of the working process) in the low-pressure cylinder 103 will enter the condenser 105 to condense into water, and the condensed water will flow to the steam water pipe of the coal-fired steam boiler 100 through the return water pipeline. The steam of the high-pressure cylinder 101, the medium-pressure cylinder 102 and the low-pressure cylinder 103 will pass into the return water heat exchanger to heat the condensed water in the return water pipeline, and the heated condensed water will pass back to the steam water pipe of the coal-fired steam boiler 100.

[0041] In one embodiment, if Figures 1 to 4 As shown, the coal-fired power generation unit 1 includes a deaerator 106 and a condensate pump 107. The return water outlet of the condenser 105 is connected to the return water inlet of the condensate pump 107. The return water heat exchanger includes a return water heat exchanger A, a return water heat exchanger B112 and a return water heat exchanger C. The return water inlet of the return water heat exchanger A is connected to the return water outlet of the condensate pump 107, and the return water outlet of the return water heat exchanger A is connected to the return water inlet of the deaerator 106. The heat source inlet of the return water heat exchanger A is connected to the steam outlet of the low-pressure cylinder 103, and the heat source outlet of the return water heat exchanger A is connected to the return water inlet of the condenser 105. The return water inlet of the return water heat exchanger B112 is connected to the return water outlet of the deaerator 106, and the return water outlet of the return water heat exchanger B112 is connected to the return water inlet of the return water heat exchanger C. The heat source inlet of the return water heat exchanger B112 is connected to the steam outlet of the medium pressure cylinder 102. The heat source outlet of the return water heat exchanger B112 is connected to the return water inlet of the deaerator 106. The return water outlet of the return water heat exchanger C is connected to the return water port of the steam water pipe, the heat source inlet of the return water heat exchanger C is connected to the steam outlet of the high pressure cylinder 101, and the heat source outlet of the return water heat exchanger C is connected to the heat source inlet of the return water heat exchanger B112.

[0042] Working principle:

[0043] The condensed water from the condenser 105 will first enter the return water heat exchanger A through the condensed water pump 107, and exchange heat with the steam heat source provided by the low-pressure cylinder 103. The condensed water after heat exchange enters the deaerator 106 for deoxygenation, and the steam heat source after heat exchange enters the condenser 105 to condense into condensed water and enters the return water heat exchanger A again. The deoxygenated condensed water returns to the return water heat exchanger B112, exchanges heat with the steam heat source provided by the medium-pressure cylinder 102, and enters the return water heat exchanger C, exchanges heat with the steam heat source provided by the high-pressure cylinder 101 and finally flows back to the steam water pipe. The steam heat source after heat exchange in the return water heat exchanger B112 and the return water heat exchanger C enters the deaerator 106, contacts the condensed water in the deaerator 106 to cool down to form condensed water, and then passes into the medium-pressure cylinder 102 after deoxygenation.

[0044] In one embodiment, if Figures 1 to 4 As shown, multiple return water heat exchangers A can be provided. Multiple return water heat exchangers A are provided in sequence, the return water inlet of the return water heat exchanger A at the head end is connected to the return water outlet of the condensate pump 107, the return water outlet of the return water heat exchanger A at the tail end is connected to the return water inlet of the deaerator 106, and the return water inlet of the latter return water heat exchanger A is connected to the return water outlet of the former return water heat exchanger A, that is, the condensate from the condensate pump 107 will enter the deaerator 106 after passing through each return water heat exchanger A in sequence. The heat source inlets of all return water heat exchangers A are connected to the steam outlet of the low-pressure cylinder 103, the heat source inlet of the rear return water heat exchanger A is connected to the heat source outlet of the front return water heat exchanger A, and the heat source outlet of the return water heat exchanger A at the head end is connected to the return water inlet of the condenser 105, that is, the low-pressure cylinder 103 will provide steam heat source for all return water heat exchangers A at the same time, and the steam heat source of the return water heat exchanger A at the end will pass through each return water heat exchanger A in turn and finally enter the condenser 105 from the return water heat exchanger A at the head end.

[0045] The number of return water heat exchangers A is set as needed, for example, four may be set: No. 1 return water heat exchanger A108, No. 2 return water heat exchanger A109, No. 3 return water heat exchanger A110 and No. 4 return water heat exchanger A111. The return water inlet of No. 1 return water heat exchanger A108 is connected to the return water outlet of condensate pump 107, the return water outlet of No. 1 return water heat exchanger A108 is connected to the return water inlet of No. 2 return water heat exchanger A109, the return water outlet of No. 2 return water heat exchanger A109 is connected to the return water inlet of No. 3 return water heat exchanger A110, the return water outlet of No. 3 return water heat exchanger A110 is connected to the return water inlet of No. 4 return water heat exchanger A111, and the return water outlet of No. 4 return water heat exchanger A111 is connected to the return water inlet of deaerator 106. The heat source inlets of the No. 1 return water heat exchanger A108, the No. 2 return water heat exchanger A109, the No. 3 return water heat exchanger A110 and the No. 4 return water heat exchanger A111 are all connected to the steam outlet of the low pressure cylinder 103, the heat source outlet of the No. 4 return water heat exchanger A111 is connected to the heat source inlet of the No. 3 return water heat exchanger A110, the heat source outlet of the No. 3 return water heat exchanger A110 is connected to the heat source inlet of the No. 2 return water heat exchanger A109, the heat source outlet of the No. 2 return water heat exchanger A109 is connected to the heat source inlet of the No. 1 return water heat exchanger A108, and the heat source outlet of the No. 1 return water heat exchanger A108 is connected to the return water inlet of the condenser 105. When setting other quantities, the above four setting methods can be referred to.

[0046] In one embodiment, if Figures 1 to 4 As shown, the steam outlet of the intermediate pressure cylinder 102 is also connected to the return water inlet of the deaerator 106 .

[0047] In one embodiment, if Figures 1 to 4 As shown, the steam water pipe in the coal-fired power generation unit 1 includes a No. 1 steam water pipe and a No. 2 steam water pipe. The steam port of the No. 1 steam water pipe is connected to the steam inlet of the high-pressure cylinder 101, and the return water port of the No. 1 steam water pipe is connected to the return water outlet of the return water heat exchanger C. The steam port of the No. 2 steam water pipe is connected to the steam inlet of the medium-pressure cylinder 102, and the return water port of the No. 2 steam water pipe is connected to the steam outlet of the high-pressure cylinder 101.

[0048] In one embodiment, if Figures 1 to 4 As shown, multiple return water heat exchangers C can be provided. Multiple return water heat exchangers C are provided in sequence, the return water inlet of the return water heat exchanger C at the head end is connected to the return water outlet of the deaerator 106, the return water outlet of the return water heat exchanger C at the end is connected to the return water port of the No. 1 steam water pipe, and the return water inlet of the rear return water heat exchanger C is connected to the return water outlet of the previous return water heat exchanger C. The heat source inlets of all the return water heat exchangers A are connected to the steam outlet of the high-pressure cylinder 101, the heat source outlet of the rear return water heat exchanger C is connected to the heat source inlet of the previous return water heat exchanger C, and the heat source outlet of the return water heat exchanger C at the head end is connected to the return water inlet of the deaerator 106.

[0049] The number of return water heat exchangers C is set as needed, for example, two can be set: No. 1 return water heat exchanger C113 and No. 2 return water heat exchanger C114. The return water inlet of No. 1 return water heat exchanger C113 is connected to the return water outlet of the deaerator 106, the return water inlet of No. 2 return water heat exchanger C114 is connected to the return water outlet of No. 1 return water heat exchanger C113, and the return water outlet of No. 2 return water heat exchanger C114 is connected to the return water port of No. 1 steam water pipe. The heat source outlet of No. 1 return water heat exchanger C113 and the heat source outlet of No. 2 return water heat exchanger C114 are both connected to the steam outlet of the high-pressure cylinder 101, the heat source outlet of No. 2 return water heat exchanger C114 is connected to the heat source inlet of No. 1 return water heat exchanger C113, and the heat source outlet of No. 1 return water heat exchanger C113 is connected to the return water inlet of the deaerator 106. When setting other numbers, you can refer to the above two settings.

[0050] In one embodiment, if Figures 1 to 4 As shown, the return water heat exchanger A adopts a low-pressure heat exchanger, and the return water heat exchangers B112 and C adopt high-pressure heat exchangers.

[0051] In one embodiment, if Figures 1 to 4As shown, it also includes a compressed air energy storage unit 3. The compressed air energy storage unit 3 includes a No. 1 compressor 300, a No. 2 compressor 301, an air storage tank 302, a No. 1 expander 303, a No. 2 expander 304, a motor 305, an energy storage unit generator 306, an energy storage heat exchanger A, an energy storage heat exchanger B, an energy storage heat exchanger C, an energy storage heat exchanger D and an energy storage heat exchanger E. The air outlet of the No. 1 compressor 300 is connected to the air inlet of the No. 2 compressor 301 through the energy storage heat exchanger A, and the air outlet of the No. 2 compressor 301 is connected to the air inlet of the air storage tank 302 through the energy storage heat exchanger B. The air storage tank 302 is connected to the air inlet of the No. 1 expander 303 through the energy storage heat exchanger C, the air outlet of the No. 1 expander 303 is connected to the air inlet of the No. 2 expander 304 through the energy storage heat exchanger D, and the air outlet of the No. 2 expander 304 discharges air through the energy storage heat exchanger E. The power of the No. 1 compressor 300 and the No. 2 compressor 301 is provided by the motor 305, the power shaft of the No. 1 compressor 300 is coaxially connected with the power shaft of the No. 2 compressor 301, and the power shaft of the No. 2 compressor 301 is coaxially connected with the output shaft of the motor 305. The No. 1 expander 303 and the No. 2 expander 304 drive the energy storage unit generator 306, the output shaft of the No. 1 expander 303 is coaxially connected with the output shaft of the No. 2 expander 304, and the output shaft of the No. 2 expander 304 is coaxially connected with the input shaft of the energy storage unit generator 306. The motor 305 and the energy storage unit generator 306 are both electrically connected to the power grid. Energy storage heat exchanger A, energy storage heat exchanger B, energy storage heat exchanger C, energy storage heat exchanger D, energy storage heat exchanger E and energy storage heat exchanger F are all connected to the return water pipeline of the coal-fired power generation unit 1.

[0052] Working principle:

[0053] During the energy storage stage, the motor 305 drives the No. 1 compressor 300 and the No. 2 compressor 301 to work. The air is compressed by the No. 1 compressor 300 and then enters the energy storage heat exchanger A, and is cooled by the feed water of the return water pipeline of the coal-fired power generation unit 1. Then, it is compressed by the No. 2 compressor 301 and then enters the energy storage heat exchanger B. It is cooled by the feed water of the return water pipeline and then stored in the air storage tank 302. In the energy release stage, the compressed air is released from the gas storage tank 302, passes through the energy storage heat exchanger C, is heated by the feed water of the return water pipeline of the coal-fired power generation unit 1, then enters the No. 1 expander 303 and then enters the energy storage heat exchanger D, is heated by the feed water of the return water pipeline, and then enters the No. 2 expander 304. The No. 1 expander 303 and the No. 2 expander 304 drive the energy storage unit generator 306 to generate electricity. After the expanded air comes out of the No. 2 expander 304, it returns to the energy storage heat exchanger E, is heated by the feed water of the return water pipeline, and is finally discharged. The air is heated by the heat exchanger before entering the No. 1 expander 303 and the No. 2 expander 304 for expansion, which can improve the expansion efficiency of the air.

[0054] In one embodiment, if Figures 1 to 4 As shown, it includes a plurality of energy storage heat exchangers A connected in series, a plurality of energy storage heat exchangers B connected in series, and a plurality of energy storage heat exchangers C connected in series.

[0055] The number of energy storage heat exchangers A, B and C is set as needed, such as: there are two energy storage heat exchangers A, including the first energy storage heat exchanger A307 and the second energy storage heat exchanger A308. There are two energy storage heat exchangers B, including the first energy storage heat exchanger B309 and the second energy storage heat exchanger BA310. There are two energy storage heat exchangers C, including the first energy storage heat exchanger C311 and the second energy storage heat exchanger CA312.

[0056] In one embodiment, if Figures 1 to 4 As shown, when the power demand is low, the compressed air energy storage unit 3 uses the excess power to drive the motor 305 to drive each compressor to compress and store the air, and the Carnot battery energy storage unit 2 stores heat through the heat pump cycle. During the peak period of electricity, the compressed air energy storage unit 3 releases the stored air, generates electricity through expansion, and the Carnot battery energy storage unit 2 releases the stored heat through the heat engine cycle to further generate electricity. The two units achieve efficient energy utilization through waste heat recovery from the coal-fired power generation unit 1, deeply coupling the three, making full use of the waste heat and waste heat of the coal-fired power plant, realizing the peak load regulation of the power system, improving the energy utilization efficiency of the system, reducing carbon emissions, and enhancing the stability of the power grid.

[0057] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A coal-fired power generation and energy storage coupling system, characterized in that: It includes a coal-fired power generation unit and a Carnot battery energy storage unit; The coal-fired power generation unit comprises a coal-fired steam boiler, a steam turbine, a coal-fired unit generator, a condenser and a return water pipeline. A steam water pipe is provided in the coal-fired steam boiler. The steam port of the steam water pipe is connected to the steam inlet of the steam turbine. The output shaft of the steam turbine is connected to the input shaft of the coal-fired unit generator. The condensed gas inlet of the condenser is connected to the exhaust steam outlet of the steam turbine. The return water outlet of the condenser is connected to the return water port of the steam water pipe through the return water pipeline. The return water pipeline exchanges heat with the steam outlet of the steam turbine through a return water heat exchanger. The Carnot battery energy storage unit includes a heat pump circulation module, an intermediate heat storage module and a heat engine circulation module; the heat pump circulation module includes a heat pump evaporator and a heat pump condenser, the heat source inlet of the heat pump evaporator is connected to the flue gas outlet of the coal-fired steam boiler, the heat transfer medium outlet of the heat pump evaporator is connected to the heat transfer medium inlet of the heat pump condenser through a compressor, and the heat transfer medium outlet of the heat pump condenser is connected to the heat transfer medium inlet of the heat pump evaporator through a throttle valve; the heat engine circulation module includes a heat engine evaporator and a heat engine condenser, and the heat transfer medium outlet of the heat engine evaporator is connected to the heat transfer medium inlet of the heat engine condenser through a heat engine module expander The heat transfer medium outlet of the heat engine condenser is connected to the heat transfer medium inlet of the heat engine evaporator through a working medium pump, the cold source inlet of the heat engine condenser is connected to the return water outlet of the condenser, and the cold source outlet of the heat engine condenser is connected to the return water port of the steam water pipe; the intermediate heat storage module includes a high-temperature tank and a low-temperature tank, the heat exchange medium inlet of the high-temperature tank is connected to the cold source outlet of the heat pump condenser, the heat exchange medium outlet of the high-temperature tank is connected to the heat source inlet of the heat engine evaporator, the heat exchange medium inlet of the low-temperature tank is connected to the heat source outlet of the heat engine evaporator, and the heat exchange medium outlet of the low-temperature tank is connected to the cold source inlet of the heat pump condenser.

2. A coal-fired power generation and energy storage coupling system according to claim 1, characterized in that: The steam turbine includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, the output shafts of the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are coaxially connected in sequence, and the output shaft of the low-pressure cylinder is coaxially connected to the input shaft of the coal-fired unit generator; the steam inlet of the high-pressure cylinder and the steam inlet of the medium-pressure cylinder are both connected to the steam port of the steam water pipe, the steam outlet of the medium-pressure cylinder is connected to the steam inlet of the low-pressure cylinder, the exhaust steam outlet is located on the low-pressure cylinder, and the steam outlet of the high-pressure cylinder, the steam outlet of the medium-pressure cylinder and the steam outlet of the low-pressure cylinder are connected to the return water heat exchanger.

3. A coal-fired power generation and energy storage coupling system according to claim 2, characterized in that: The coal-fired power generation unit includes a deaerator and a condensate pump, and the return water outlet of the condenser is connected to the return water inlet of the condensate pump; the return water heat exchanger includes a return water heat exchanger A, a return water heat exchanger B and a return water heat exchanger C, the return water inlet of the return water heat exchanger A is connected to the return water outlet of the condensate pump, the return water outlet of the return water heat exchanger A is connected to the return water inlet of the deaerator, the heat source inlet of the return water heat exchanger A is connected to the steam outlet of the low-pressure cylinder, and the heat source outlet of the return water heat exchanger A is connected to the return water inlet of the condenser; the return water heat exchanger The return water inlet of the return water heat exchanger B is connected with the return water outlet of the deaerator, the return water outlet of the return water heat exchanger B is connected with the return water inlet of the return water heat exchanger C, the heat source inlet of the return water heat exchanger B is connected with the steam outlet of the intermediate pressure cylinder, the heat source outlet of the return water heat exchanger B is connected with the return water inlet of the deaerator, the return water outlet of the return water heat exchanger C is connected with the return water port of the steam water pipe, the heat source inlet of the return water heat exchanger C is connected with the steam outlet of the high pressure cylinder, and the heat source outlet of the return water heat exchanger C is connected with the heat source inlet of the return water heat exchanger B.

4. A coal-fired power generation and energy storage coupling system according to claim 3, characterized in that: It comprises a plurality of return water heat exchangers A arranged in sequence, the return water inlet of the return water heat exchanger A at the head end is connected with the return water outlet of the condensing water pump, the return water outlet of the return water heat exchanger A at the tail end is connected with the return water inlet of the deaerator, the return water inlet of the rear return water heat exchanger A is connected with the return water outlet of the front return water heat exchanger A, the heat source inlets of all the return water heat exchangers A are connected with the steam outlet of the low-pressure cylinder, the heat source inlet of the rear return water heat exchanger A is connected with the heat source outlet of the front return water heat exchanger A, and the heat source outlet of the return water heat exchanger A at the head end is connected with the return water inlet of the condenser.

5. A coal-fired power generation and energy storage coupling system according to claim 3, characterized in that: The steam outlet of the intermediate pressure cylinder is also connected to the return water inlet of the deaerator.

6. A coal-fired power generation and energy storage coupling system according to claim 5, characterized in that: The steam water pipe includes a No. 1 steam water pipe and a No. 2 steam water pipe. The steam port of the No. 1 steam water pipe is connected to the steam inlet of the high-pressure cylinder, the return water port of the No. 1 steam water pipe is connected to the return water outlet of the return water heat exchanger C, the steam port of the No. 2 steam water pipe is connected to the steam inlet of the medium-pressure cylinder, and the return water port of the No. 2 steam water pipe is connected to the steam outlet of the high-pressure cylinder.

7. A coal-fired power generation and energy storage coupling system according to claim 6, characterized in that: It comprises a plurality of return water heat exchangers C arranged in sequence, the return water inlet of the return water heat exchanger C at the head end is connected with the return water outlet of the deaerator, the return water outlet of the return water heat exchanger C at the tail end is connected with the return water port of the No. 1 steam water pipe, the return water inlet of the rear return water heat exchanger C is connected with the return water outlet of the front return water heat exchanger C, the heat source inlets of all the return water heat exchangers A are connected with the steam outlet of the high-pressure cylinder, the heat source outlet of the rear return water heat exchanger C is connected with the heat source inlet of the front return water heat exchanger C, and the heat source outlet of the return water heat exchanger C at the head end is connected with the return water inlet of the deaerator.

8. A coal-fired power generation and energy storage coupling system according to claim 7, characterized in that: The water return heat exchanger A is a low-pressure heat exchanger, and the water return heat exchanger B and the water return heat exchanger C are high-pressure heat exchangers.

9. A coal-fired power generation and energy storage coupling system according to claim 1, characterized in that: The compressed air energy storage unit includes a No. 1 compressor, a No. 2 compressor, an air storage tank, a No. 1 expander, a No. 2 expander, an electric motor and an energy storage unit generator. The air outlet of the No. 1 compressor is connected to the air inlet of the No. 2 compressor through an energy storage heat exchanger A. The air outlet of the No. 2 compressor is connected to the air inlet of the air storage tank through an energy storage heat exchanger B. The air storage tank is connected to the air inlet of the No. 1 expander through an energy storage heat exchanger C. The air outlet of the No. 1 expander is connected to the air inlet of the No. 1 expander through an energy storage heat exchanger C. The energy storage heat exchanger D is connected to the air inlet of the No. 1 expander, and the air outlet of the No. 1 expander discharges air through the energy storage heat exchanger E. The power of the No. 1 compressor and the No. 2 compressor is provided by an electric motor. The No. 1 expander and the No. 2 expander drive the energy storage unit generator. The electric motor and the energy storage unit generator are both electrically connected to the power grid. The energy storage heat exchanger A, energy storage heat exchanger B, energy storage heat exchanger C, energy storage heat exchanger D and energy storage heat exchanger E are all connected to the return water pipeline.

10. A coal-fired power generation and energy storage coupling system according to claim 9, characterized in that: It includes a plurality of energy storage heat exchangers A connected in series, a plurality of energy storage heat exchangers B connected in series, and a plurality of energy storage heat exchangers C connected in series.

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