Heat storage peak shaving device and system for thermal power generating unit

Abstract

The present disclosure relates to a heat storage peak regulation device and system of a thermal power unit, and relates to the technical field of power generation. The heat storage peak regulation device of the thermal power unit can realize efficient storage and release of the excess heat load of the boiler through the arrangement of six groups of heat exchangers and high / low-temperature heat exchange medium storage tanks, thereby improving the deep peak regulation and peak shaving capacity of the thermal power unit. Specifically, the first heat exchanger and the second heat exchanger extract heat from the main steam and the heat reheat steam of the boiler respectively, and the third heat exchanger further extracts heat from the main steam. The excess heat load of the boiler is converted into energy storage, the steam output from the boiler to the steam turbine is reduced, and the power output of the generator is reduced, thereby realizing deep peak regulation. The high-temperature heat exchange medium storage tank is used for storing heat, providing guarantee for subsequent peak operation of the thermal power unit. The fourth, fifth and sixth heat exchangers can efficiently release the stored heat and output to the steam turbine through cascade heat exchange, improve the power output of the generator, and thereby realize peak shaving.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of power generation, in particular, to a heat storage peak regulation device and system of a thermal power unit. BACKGROUND

[0002] Thermal power generation is one of the main performance energy sources of power supply in China. The key equipment of a thermal power unit includes a boiler, a steam turbine, and a generator. The boiler uses fossil fuels to burn to generate high-temperature and high-pressure main steam. The high-temperature and high-pressure main steam enters the steam turbine and does work to drive the generator rotor to rotate. The generator converts mechanical energy into electrical energy and outputs to the power grid.

[0003] However, as the installed capacity of new energy continues to expand and the peak-valley difference of power grid load continues to increase, the thermal power unit needs to bear a greater peak regulation task. During the low electricity consumption period or when the new energy output is sufficient, the thermal power unit needs to operate at a reduced load. However, even if the boiler of the thermal power unit operates at the lowest stable combustion load, it may still be unable to meet the peak regulation demand. At this time, the heat storage peak regulation device can be used to assist the thermal power unit to achieve deep peak regulation. During the peak electricity consumption period or when the new energy output is insufficient, the thermal power unit needs to operate at an increased load. However, when the boiler reaches the rated load, it may still be unable to meet the peak demand. At this time, the heat storage peak regulation device can be used to assist the thermal power unit to achieve peak.

[0004] However, the related heat storage peak regulation device has limited ability to assist the thermal power unit to achieve deep peak regulation and peak. Therefore, improving the deep peak regulation and peak capacity of the thermal power unit is a technical problem to be solved at present. SUMMARY

[0005] To solve the above problems, the present disclosure provides a heat storage peak regulation device and system of a thermal power unit.

[0006] In a first aspect, the present disclosure provides a heat storage peak regulation device of a thermal power unit, the thermal power unit comprising a boiler and a deaerator, the device comprising: a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a sixth heat exchanger, a high-temperature heat exchange medium storage tank, and a low-temperature heat exchange medium storage tank, wherein:

[0007] The gas inlet of the first heat exchanger is used to communicate with the main steam outlet of the boiler, the gas outlet is used to communicate with the cold reheat steam inlet of the boiler, the gas outlet is also used to communicate with the gas inlet of the third heat exchanger, the heat exchange medium inlet is used to communicate with the heat exchange medium outlet of the third heat exchanger, and the heat exchange medium outlet is used to communicate with the inlet of the high-temperature heat exchange medium storage tank;

[0008] The second heat exchanger, a gas inlet thereof is communicated with a hot reheat steam outlet of the boiler, a gas outlet thereof is communicated with a cold reheat steam inlet of the boiler, a heat exchange medium inlet thereof is communicated with a heat exchange medium outlet of the third heat exchanger, and a heat exchange medium outlet thereof is communicated with an inlet of the high-temperature heat exchange medium storage tank;

[0009] The third heat exchanger, a gas outlet thereof is communicated with a cold reheat steam inlet of the boiler, a heat exchange medium inlet thereof is communicated with an outlet of the low-temperature heat exchange medium storage tank, and a feedwater outlet thereof is communicated with a feedwater inlet of the boiler;

[0010] The fourth heat exchanger, a gas inlet thereof is communicated with a gas outlet of the fifth heat exchanger, a gas outlet thereof is communicated with a cold reheat steam inlet of the boiler, a heat exchange medium inlet thereof is communicated with an outlet of the high-temperature heat exchange medium storage tank, and a heat exchange medium outlet thereof is communicated with a heat exchange medium inlet of the fifth heat exchanger;

[0011] The fifth heat exchanger, a heat exchange medium outlet thereof is communicated with a heat exchange medium inlet of the sixth heat exchanger, and a feedwater inlet thereof is communicated with a feedwater outlet of the sixth heat exchanger;

[0012] The sixth heat exchanger, a heat exchange medium outlet thereof is communicated with an inlet of the low-temperature heat exchange medium storage tank, and a feedwater inlet thereof is communicated with a feedwater outlet of the deaerator.

[0013] Optionally, the first heat exchanger and the second heat exchanger are gas-liquid heat exchangers, and the third heat exchanger is a condenser.

[0014] Optionally, the fourth heat exchanger is a superheater, the fifth heat exchanger is an evaporator, and the sixth heat exchanger is a preheater.

[0015] Optionally, a pressure matcher is further included, an inlet thereof is communicated with a gas outlet of the first heat exchanger and a gas outlet of the second heat exchanger, and an outlet thereof is communicated with a cold reheat steam inlet of the boiler.

[0016] Optionally, a cold salt pump is further included, an inlet thereof is communicated with an outlet of the low-temperature heat exchange medium storage tank, and an outlet thereof is communicated with a heat exchange medium inlet of the third heat exchanger.

[0017] Optionally, a first feedwater pump is further included, an inlet thereof is communicated with a feedwater outlet of the third heat exchanger, and an outlet thereof is communicated with a feedwater inlet of the boiler.

[0018] Optionally, a hot salt pump is further included, an inlet thereof is communicated with an outlet of the high-temperature heat exchange medium storage tank, and an outlet thereof is communicated with a heat exchange medium inlet of the fourth heat exchanger.

[0019] Optionally, a second feedwater pump is further included, an inlet of which is configured to communicate with the feedwater outlet of the deaerator, and an outlet of which is configured to communicate with the feedwater inlet of the sixth heat exchanger.

[0020] Optionally, the heat exchange medium is Hitec ternary salt.

[0021] In a second aspect, the present disclosure further provides a thermal storage peak regulation system of a thermal power unit, comprising a thermal power unit and a thermal storage peak regulation device of the thermal power unit according to any one of the first aspect.

[0022] The technical scheme, the thermal storage peak regulation device of the thermal power unit can realize efficient storage and release of the excess heat load of the boiler through the arrangement of the six groups of heat exchangers and the high-temperature and low-temperature heat exchange medium storage tanks, so as to improve the deep peak regulation and peak shaving capacity of the thermal power unit. Specifically, the first heat exchanger and the second heat exchanger extract heat from the main steam and the heat reheat steam of the boiler, respectively, and the third heat exchanger further extracts heat from the main steam. The multi-stage heat exchange design can make the heat recovery more sufficient, convert the excess heat load of the boiler into energy storage, reduce the steam output from the boiler to the steam turbine, and reduce the output of the generator, so as to realize deep peak regulation. The high-temperature heat exchange medium storage tank is used for storing heat, providing guarantee for subsequent peak operation of the thermal power unit. The fourth, fifth and sixth heat exchangers can efficiently release the stored heat and output to the steam turbine, thereby improving the output of the generator and realizing peak shaving.

[0023] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation of the present disclosure. In the drawings:

[0025] Figure 1 is a structural diagram of a thermal storage peak regulation device of a thermal power unit according to an exemplary embodiment;

[0026] Figure 2 is a structural diagram of a thermal storage peak regulation device of a thermal power unit according to another exemplary embodiment.

[0027] LIST OF ELEMENTS

[0028] The heat storage peak shaving device 100, the first heat exchanger 111, the second heat exchanger 112, the third heat exchanger 113, the fourth heat exchanger 114, the fifth heat exchanger 115, the sixth heat exchanger 116, the high-temperature heat medium storage tank 121, the low-temperature heat medium storage tank 122, the pressure matching device 130, the cold salt pump 141, the first feed water pump 151, the condensate water storage tank 1511, the electric regulating valve 1512, the electric valve 1513, the hot salt pump 142, the second feed water pump 152, the thermal power unit 200, the boiler 210, the high-pressure cylinder 221, the medium-pressure cylinder 222, the low-pressure cylinder 223, the generator 230, the condenser 240, the condensate pump 250, the low-pressure heater 261, the deaerator 270, the feed water pump 280, the high-pressure heater 262. DETAILED DESCRIPTION

[0029] The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0030] Herein, the terms "first", "second", and the like are merely used to distinguish one element from another element, and do not require or imply that there is any actual relationship or order between the elements. In fact, the first element can also be referred to as the second element, and vice versa.

[0031] Moreover, the term "comprising" is intended to encompass non-exclusive inclusion, such that a structure, device, or apparatus that comprises a series of elements includes not only those elements, but also other elements not explicitly listed, or inherent to such structure, device, or apparatus.

[0032] Figure 1 is a structural diagram of a heat storage peak shaving device 100 of a thermal power unit according to an exemplary embodiment. As shown in FIG. 1, the heat storage peak shaving device 100 includes a first heat exchanger 111, a second heat exchanger 112, a third heat exchanger 113, a fourth heat exchanger 114, a fifth heat exchanger 115, a sixth heat exchanger 116, a high-temperature heat medium storage tank 121, a low-temperature heat medium storage tank 122, a pressure matching device 130, a cold salt pump 141, a first feed water pump 151, a condensate water storage tank 1511, an electric regulating valve 1512, an electric valve 1513, a hot salt pump 142, a second feed water pump 152, a thermal power unit 200, a boiler 210, a high-pressure cylinder 221, a medium-pressure cylinder 222, a low-pressure cylinder 223, a generator 230, a condenser 240, a condensate pump 250, a low-pressure heater 261, a deaerator 270, a feed water pump 280, and a high-pressure heater 262. Figure 1As shown, the thermal power unit 200 includes a boiler 210 and a deaerator 270, and the device includes: a first heat exchanger 111, a second heat exchanger 112, a third heat exchanger 113, a fourth heat exchanger 114, a fifth heat exchanger 115, a sixth heat exchanger 116, a high-temperature heat exchange medium storage tank 121, and a low-temperature heat exchange medium storage tank 122, wherein: the first heat exchanger 111, a gas inlet thereof is used in communication with a main steam outlet of the boiler 210, a gas outlet thereof is used in communication with a cold reheat steam inlet of the boiler 210, the gas outlet is also in communication with a gas inlet of the third heat exchanger 113, a heat exchange medium inlet thereof is in communication with a heat exchange medium outlet of the third heat exchanger 113, and a heat exchange medium outlet thereof is in communication with an inlet of the high-temperature heat exchange medium storage tank 121; the second heat exchanger 112, a gas inlet thereof is used in communication with a hot reheat steam outlet of the boiler 210, a gas outlet thereof is used in communication with a cold reheat steam inlet of the boiler 210, a heat exchange medium inlet thereof is in communication with a heat exchange medium outlet of the third heat exchanger 113, and a heat exchange medium outlet thereof is in communication with an inlet of the high-temperature heat exchange medium storage tank 121; the third heat exchanger 113, a gas outlet thereof is used in communication with a cold reheat steam inlet of the boiler 210, a heat exchange medium inlet thereof is in communication with an outlet of the low-temperature heat exchange medium storage tank 122, and a feedwater outlet thereof is used in communication with a feedwater inlet of the boiler 210; the fourth heat exchanger 114, a gas inlet thereof is in communication with a gas outlet of the fifth heat exchanger 115, a gas outlet thereof is used in communication with a cold reheat steam inlet of the boiler 210, a heat exchange medium inlet thereof is in communication with an outlet of the high-temperature heat exchange medium storage tank 121, and a heat exchange medium outlet thereof is in communication with a heat exchange medium inlet of the fifth heat exchanger 115; the fifth heat exchanger 115, a heat exchange medium outlet thereof is in communication with a heat exchange medium inlet of the sixth heat exchanger 116, and a feedwater inlet thereof is in communication with a feedwater outlet of the sixth heat exchanger 116; and the sixth heat exchanger 116, a heat exchange medium outlet thereof is in communication with an inlet of the low-temperature heat exchange medium storage tank 122, and a feedwater inlet thereof is used in communication with a feedwater outlet of the deaerator 270.

[0033] First, the thermal power unit 200 is described. Referring to FIG. 1, the thermal power unit 200 includes a boiler 210, a steam turbine 220, a generator 230, a condenser 240, a deaerator 270, and a feedwater heater 280. Figure 1The thermal power unit 200 includes a boiler 210, a high-pressure cylinder 221, a medium-pressure cylinder 222, a low-pressure cylinder 223, a generator 230, a condenser 240, a condensate pump 250, a low-pressure heater 261, a deaerator 270, a feedwater pump 280, and a high-pressure heater 262. The boiler 210 heats feedwater to generate high-temperature and high-pressure steam by burning fossil fuels such as coal. The high-pressure cylinder 221 first receives the steam of the highest parameters output by the boiler 210, gradually expands to the medium-pressure cylinder 222 and the low-pressure cylinder 223, and finally discharges low-pressure steam. The high-pressure cylinder 221, the medium-pressure cylinder 222, and the low-pressure cylinder 223 form a steam turbine, which uses high-temperature and high-pressure steam to drive the rotor of the generator 230 to rotate and generate electricity. The generator 230 converts the mechanical energy of the steam turbine into electrical energy and outputs it to the power grid. The condenser 240 condenses the low-pressure steam discharged from the steam turbine into water using cooling water. The condensate pump 250 transports the condensate in the condenser 240 to the low-pressure heater 261. The low-pressure heater 261 heats the condensate using low-pressure steam extracted from the steam turbine. The heated condensate is sent to the deaerator 270. The deaerator 270 deaerates the feedwater to remove dissolved gases in the water. The deaerator 270 also extracts low-pressure steam from the medium-pressure cylinder 222 to heat the feedwater to the saturation temperature at the pressure of the deaerator 270. The feedwater pump 280 sends the deaerated feedwater to the high-pressure heater 262. The high-pressure heater 262 heats the feedwater using medium-high pressure steam extracted from the steam turbine. The heated feedwater is sent back to the boiler 210 for the next power generation cycle.

[0034] The boiler 210 of the thermal power unit 200 includes an economizer, a reheater, and a superheater. The economizer is located in the boiler 210 outlet flue, which is used to absorb the remaining heat in the flue gas. The economizer uses this heat to heat the feedwater again, improving the overall thermal efficiency. The feedwater inlet of the economizer is connected to the feedwater outlet of the high-pressure heater. The reheater is located on the heating surface pipeline of the boiler 210, which is used to heat the steam discharged from the high-pressure cylinder 221 again. The superheater is located on the heating surface pipeline of the boiler 210, which absorbs the heat of the furnace and the flue to make the steam reach a higher temperature and pressure, forming superheated steam.

[0035] Secondly, the technical terms in the heat storage peak shaving device 100 of the above thermal power unit are explained. The first to sixth heat exchangers refer to devices that exchange heat between different fluids, including two independent flow channels on the hot side and the cold side. The heat exchange medium refers to the heat transfer working medium circulating in the heat storage peak shaving device 100 of the above thermal power unit, which is used for heat storage and release. The high / low temperature heat exchange medium storage tank is a pressure vessel for storing the same heat exchange medium. The difference is that the temperature of the heat exchange medium stored in the high-temperature heat exchange medium storage tank 121 is higher than that of the heat exchange medium stored in the low-temperature heat exchange medium storage tank 122.

[0036] High-temperature main steam refers to high-temperature and high-pressure steam output from the outlet of the superheater of the boiler 210, which is the main power source for driving the steam turbine of the thermal power unit 200. Cold reheat steam refers to low-temperature steam after being discharged from the high-pressure cylinder 221 and before being input into the reheater. Hot reheat steam refers to high-temperature steam obtained by heating the cold reheat steam in the reheater of the boiler 210. Feed water refers to water supplied to the thermal storage peak shaving device 100 of the boiler 210 / thermal power unit.

[0037] Based on the above thermal power unit 200, the peak shaving and heat storage process and the peak shedding and heat release process that can be performed by the thermal storage peak shaving device 100 of the thermal power unit are described.

[0038] The peak shaving and heat storage process is used in the case where the boiler 210 is at the minimum stable combustion load and the power output of the generator 230 is to be further reduced. The process refers to a process of transferring the excess heat load of the boiler 210 to the heat exchange medium through the heat exchanger of the above-mentioned thermal storage peak shaving device and storing the heat, so as to achieve deep peak shaving.

[0039] The main path of the peak shaving and heat storage process is that the main steam generated by the boiler 210 enters the first heat exchanger 111, the reheat steam generated by the boiler enters the second heat exchanger 112, and the low-temperature heat exchange medium flows through the first, second, and third heat exchangers and finally reaches the high-temperature heat exchange medium storage tank 121.

[0040] The conversion process of the main steam is as follows. (1) The main steam generated by the boiler 210 enters the gas inlet of the first heat exchanger 111. Specifically, the main steam generated by the superheater of the boiler 210 enters the gas inlet of the first heat exchanger 111. (2) The main steam exchanges heat with the lower-temperature heat exchange medium in the first heat exchanger 111, forming lower-temperature steam and high-temperature heat exchange medium. (3) Part of the lower-temperature steam returns to the cold reheat steam inlet of the boiler 210, specifically, to the cold reheat steam inlet of the reheater of the boiler 210. (4) Another part of the lower-temperature steam enters the third heat exchanger 113 to continue heat exchange with the low-temperature heat exchange medium, forming water and lower-temperature heat exchange medium. The water output by the third heat exchanger 113 is delivered to the feed water inlet of the economizer of the boiler 210 as the feed water of the boiler 210.

[0041] The conversion process of the hot reheat steam is as follows. (1) The hot reheat steam of the boiler 210 enters the gas inlet of the second heat exchanger 112. Specifically, the hot reheat steam generated by the reheater enters the gas inlet of the second heat exchanger 112. (2) The hot reheat steam exchanges heat with the lower-temperature heat exchange medium in the second heat exchanger 112, forming low-temperature steam and high-temperature heat exchange medium. (3) The low-temperature steam returns to the cold reheat steam inlet of the boiler 210, specifically, to the cold reheat steam inlet of the reheater.

[0042] The conversion process of the low-temperature heat exchange medium is as follows. (1) The low-temperature heat exchange medium enters the heat exchange medium inlet of the third heat exchanger 113 from the outlet of the low-temperature heat exchange medium storage tank 122. (2) The low-temperature heat exchange medium exchanges heat with the lower-temperature steam in the third heat exchanger 113 to form lower-temperature heat exchange medium and water. (3) Part of the lower-temperature medium exchanges heat with the main steam in the first heat exchanger 111 to form part of the high-temperature heat exchange medium and lower-temperature steam. (4) Another part of the lower-temperature medium exchanges heat with the hot reheat steam in the second heat exchanger 112 to form another part of the high-temperature heat exchange medium and low-temperature steam. (5) The two parts of the high-temperature heat exchange medium finally enter the high-temperature heat exchange medium storage tank 121 for storage.

[0043] The peak heat release process is used when the boiler 210 is at rated load and the output of the generator 230 is to be further increased. It refers to the process of transferring the heat stored in the heat storage peak regulation device to the high-temperature steam through the heat exchangers and delivering it to the thermal power unit 200 to achieve peak output. The specific process of peak heat release is as follows.

[0044] The main path of peak regulation and heat storage is that the high-temperature heat exchange medium is released from the high-temperature heat exchange medium storage tank 121, passes through the fourth heat exchanger 114 and the fifth heat exchanger 115, and finally returns to the low-temperature heat exchange medium storage tank 122 through the sixth heat exchanger 116.

[0045] The conversion process of the high-temperature heat exchange medium is as follows. (1) The high-temperature heat exchange medium enters the heat exchange medium inlet of the fourth heat exchanger 114 from the outlet of the high-temperature storage tank. (2) The high-temperature heat exchange medium exchanges heat with the higher-temperature steam in the fourth heat exchanger 114 to form higher-temperature heat exchange medium and high-temperature steam. (3) The higher-temperature heat exchange medium exchanges heat with the high-temperature feed water in the fifth heat exchanger 115 to form lower-temperature heat exchange medium and higher-temperature steam. (4) The lower-temperature heat exchange medium exchanges heat with the low-temperature feed water in the sixth heat exchanger 116 to form low-temperature heat exchange medium and high-temperature feed water. (5) The low-temperature heat exchange medium is stored in the low-temperature heat exchange medium storage tank 122.

[0046] The conversion process of the low-temperature feed water is as follows. (1) The low-temperature feed water of the boiler 210 first enters the feed water inlet of the sixth heat exchanger 116 through the feed water outlet of the deaerator 270 as the feed water of the heat storage peak regulation device 100 of the thermal power unit. (2) The low-temperature feed water exchanges heat with the lower-temperature heat exchange medium in the sixth heat exchanger 116 to form high-temperature feed water and low-temperature heat exchange medium. (3) The high-temperature feed water exchanges heat with the higher-temperature heat exchange medium in the fifth heat exchanger 115 to form higher-temperature steam and lower-temperature heat exchange medium. (4) Finally, it passes through other heat exchangers and enters the boiler 210.

[0047] It should be understood that the main steam and the hot reheat steam have the same temperature, about 540-600 degrees Celsius, and both can be used for heat storage. The heat storage peak shaving device 100 of the above thermal power unit extracts the steam of the two parts for heat storage, which can double the absorption of the remaining load of the boiler 210, realize double reduction of the output of the generator 230, and thus more deeply regulate the peak. Because the main steam has a higher pressure than the reheat steam, a part of the main steam can be re-heated to preheat the low-temperature heat medium to fully extract the heat of the main steam. After the re-heating of a part of the main steam, water is formed, which is supplemented to the boiler 210 to balance the steam-water circulation system of the boiler 210.

[0048] In addition, the water at the outlet of the deaerator 270 has removed oxygen and other harmful gases, and a part of the feed water of the boiler 210 is led out from the deaerator 270 as the feed water of the heat storage peak shaving device 100 of the above thermal power unit, which can prevent the corrosion of the heat storage peak shaving device 100 of the above thermal power unit, thereby improving the service life thereof. The high-temperature steam output by the fourth heat exchanger 114 is used to improve the output of the thermal power unit 200. The high-temperature steam is delivered to the cold reheat steam inlet of the boiler 210. Specifically, the high-temperature steam is used to be delivered to the cold reheat steam inlet of the reheater. After the high-temperature steam is mixed and heated with the remaining steam in the reheater, the hot reheat steam is generated. The hot reheat steam is sequentially delivered to the medium-pressure cylinder 222 and the low-pressure cylinder 223 to work, thereby improving the output of the thermal power unit 200.

[0049] The above technical solution can realize efficient storage and release of the excess heat load of the boiler 210 through the arrangement of six groups of heat exchangers and high and low temperature heat medium storage tanks 122, thereby improving the deep peak shaving and peak shaving capacity of the thermal power unit 200. Specifically, the first heat exchanger 111 and the second heat exchanger 112 extract heat from the main steam and the hot reheat steam of the boiler 210, respectively, and the third heat exchanger 113 further extracts heat from the main steam. The multi-stage heat exchange design can make the heat recovery more sufficient, convert the excess heat load of the boiler 210 into energy storage, reduce the steam output by the boiler 210 to the steam turbine, reduce the output of the generator 230, and thus realize deep peak shaving. The high-temperature heat medium storage tank 121 is used to store heat to provide guarantee for subsequent peak shaving of the thermal power unit 200. The fourth, fifth and sixth heat exchangers can efficiently release the stored heat and output to the steam turbine to improve the output of the generator 230, thereby realizing peak shaving.

[0050] The heat storage peak shaving device can further comprise a first valve arranged between the gas outlet of the superheater and the gas inlet of the first heat exchanger 111, for controlling whether the main steam enters the heat storage peak shaving device for heat storage. The heat storage peak shaving device can further comprise a second valve arranged between the gas outlet of the reheater and the gas inlet of the second heat exchanger 112, for controlling whether the hot reheat steam enters the heat storage peak shaving device for heat storage. The heat storage peak shaving device can further comprise a third valve arranged between the feedwater inlet of the economizer and the gas outlet of the fourth heat exchanger 114, for controlling whether the high-temperature steam is released into the thermal power generating unit 200 for heat release.

[0051] In an embodiment, the first heat exchanger 111 and the second heat exchanger 112 can be gas-liquid heat exchangers, and the third heat exchanger 113 can be a condenser.

[0052] It should be understood that the first heat exchanger 111 performs heat exchange between the gaseous main steam and the liquid heat exchange medium, and thus can be a gas-liquid heat exchanger. Since the main steam has high temperature and high pressure, in actual selection, a gas-liquid heat exchanger that can withstand high temperature and high pressure and keep the gas phase and the liquid phase effectively separated should be selected as the first heat exchanger 111. The second heat exchanger 112 performs heat exchange between the gaseous hot reheat steam and the liquid heat exchange medium, and thus can also be a gas-liquid heat exchanger. Since the hot reheat steam has high temperature and relatively high pressure, in actual selection, a gas-liquid heat exchanger that can withstand high temperature and high pressure and keep the gas phase and the liquid phase effectively separated should also be selected as the second heat exchanger 112. The third heat exchanger 113 performs heat exchange for completely condensing the steam into water, and thus can be a condenser. Through the condenser, the latent heat in the steam can be fully recovered, and energy loss can be reduced.

[0053] In an embodiment, the fourth heat exchanger 114 can be a superheater, the fifth heat exchanger 115 can be an evaporator, and the sixth heat exchanger 116 can be a preheater.

[0054] It should be understood that the sixth heat exchanger 116 performs preheating of the feedwater outlet from the deaerator 270, and thus can be a preheater. Through the preheater, the temperature of the feedwater can be increased using low-grade heat, and the load of the fifth and fourth heat exchangers can be reduced. The fifth heat exchanger 115 performs a gas-liquid phase change process of the feedwater, and thus can be an evaporator. Through the evaporator, the preheated feedwater can be converted into saturated steam, and the heat of the high-temperature heat exchange medium can be fully utilized. The sixth heat exchanger 116 performs a process of heating the steam to a superheated state, and thus can be a superheater. Through the superheater, the steam can be ensured to reach a sufficient superheat degree to enter the reheat steam inlet of the reheater. Through the above three heat exchangers, the cascade utilization of heat can be achieved, and the heat in the high-temperature heat exchange medium can be fully extracted.

[0055] Figure 2is a structural diagram of a heat storage peak shaving device 100 of a thermal power unit according to another exemplary embodiment. In an embodiment, as shown in Figure 2 The device can further include a pressure matcher 130, an inlet of which is in communication with the gas outlet of the first heat exchanger 111 and the gas outlet of the second heat exchanger 112, and an outlet of which is configured to communicate with the cold reheat steam inlet of the boiler 210.

[0056] It should be understood that the steam output by the first heat exchanger 111 and the second heat exchanger 112 has different pressures, and can not meet the pressure requirement of the reheat steam of the reheater, so the pressure matcher 130 is needed to adjust the pressure of the two parts of steam. The steam output by the first heat exchanger 111 and the second heat exchanger 112 can be smoothly mixed by the pressure matcher 130, preventing steam backflow and pressure fluctuation, thereby reducing the impact on the cold reheat steam inlet of the reheat.

[0057] In an embodiment, as shown in Figure 2 The device can further include a cold salt pump 141, an inlet of which is in communication with the outlet of the low-temperature heat exchange medium storage tank 122, and an outlet of which is in communication with the heat exchange medium inlet of the third heat exchanger 113.

[0058] It should be understood that the low-temperature heat exchange medium is stored in the low-temperature heat exchange medium storage tank 122, and an external force is needed to extract the low-temperature heat exchange medium from the storage tank and deliver it to the corresponding heat exchanger. The heat exchange medium is usually low-temperature molten salt. Therefore, the cold salt pump 141 can be arranged between the low-temperature heat exchange medium storage tank 122 and the third heat exchanger 113 to drive the delivery of the low-temperature heat exchange medium, ensuring the circulation of the heat exchange medium.

[0059] In an embodiment, as shown in Figure 2 The device can further include a first feed water pump 151, an inlet of which is in communication with the feed water outlet of the third heat exchanger 113, and an outlet of which is configured to communicate with the feed water inlet of the boiler 210.

[0060] It should be understood that the water output by the third heat exchanger 113 needs to overcome the pressure of the feed water system of the boiler 210 to be delivered to the feed water system of the boiler 210, so the first feed water pump 151 can be arranged between the third heat exchanger 113 and the boiler 210. Through the first feed water pump 151, the stability of the water flow can also be ensured. And by adjusting the first feed water pump 151, the requirement of the feed water pressure of the boiler 210 can be met.

[0061] In an embodiment, as shown in Figure 2As shown, the device may further include a condensate storage tank 1511, an electrically adjustable valve 1512, and an electrically adjustable valve 1513, wherein: the first inlet of the condensate storage tank 1511 is connected to the water supply outlet of the third heat exchanger 113, and its outlet is connected to the inlet of the first water supply pump 151; the inlet of the electrically adjustable valve 1512 is connected to the outlet of the first water supply pump 151, and its outlet is connected to the inlet of the electrically adjustable valve 1513; the outlet of the electrically adjustable valve 1513 is connected to the second inlet of the condensate storage tank 1511.

[0062] Here, the condensate storage tank 1511 is a container for storing condensate. The electrically controlled regulating valve 1512 has the function of finely adjusting the opening degree, which can precisely control the flow rate of condensate. However, the sealing performance of this valve in the fully closed state is relatively low. While the electrically controlled valve 1513 cannot finely adjust the opening degree and can only achieve a fully open or fully closed state, it has a higher sealing performance when fully closed, and can better cut off the flow of condensate.

[0063] It should be understood that during the initial and later stages of operation of the thermal storage and peak-shaving device, the output of condensate from the third heat exchanger is relatively low, which may prevent the first feedwater pump 151 from starting and operating normally. This is because the condensate flow rate and pressure at this time may not meet the operating requirements of the first feedwater pump 151. Specifically, the condensate flow rate must not be lower than the minimum flow rate of the first feedwater pump 151, and the condensate pressure must not be lower than the minimum pressure required by the pump.

[0064] Therefore, condensate can be stored in the condensate storage tank 1511 to create sufficient water pressure and flow rate to meet the operating conditions of the first feed water pump 151. When the condensate in the condensate storage tank 1511 is about to fail to meet the operating requirements of the first feed water pump 151, the electric valve 1513 can be opened, and the flow rate can be adjusted by the electric regulating valve 1512, so that the condensate output by the first feed water pump 151 flows back to the condensate storage tank 1511 to maintain the minimum circulation flow rate and meet the operating requirements of the first feed water pump 151.

[0065] In one embodiment, such as Figure 2 As shown, the device may also include a hot salt pump 142, the inlet of which is connected to the outlet of the high-temperature heat exchange medium storage tank 121, and the outlet of which is connected to the heat exchange medium inlet of the fourth heat exchanger 114.

[0066] It should be understood that the high-temperature heat exchange medium is stored in the high-temperature heat exchange medium storage tank 121, and external force is required to extract the high-temperature heat exchange medium from the storage tank and transport it to the corresponding heat exchanger. This heat exchange medium is typically high-temperature molten salt. Therefore, a hot salt pump 142 can be installed between the high-temperature heat exchange medium storage tank 121 and the fourth heat exchanger 114 to drive the transport of the high-temperature heat exchange medium and ensure its circulation.

[0067] In one embodiment, such as Figure 2 As shown, the device may also include a second feedwater pump 152, the inlet of which is connected to the feedwater outlet of the deaerator 270, and the outlet of which is connected to the feedwater inlet of the sixth heat exchanger 116.

[0068] It should be understood that the feedwater from the outlet of the deaerator 270 is supplied to the heat storage and peak-shaving device 100 of the aforementioned thermal power unit. Therefore, a second feedwater pump 152 can be installed between the sixth heat exchanger 116 and the deaerator 270. The second feedwater pump 152 also ensures stable water flow. Furthermore, by adjusting the second feedwater pump 152, the feedwater pressure requirements of the heat storage and peak-shaving device 100 of the aforementioned thermal power unit can be met.

[0069] In one embodiment, the heat exchange medium may be a Hitec ternary salt.

[0070] Here, the Hitec ternary salt is composed of 7% NaNO3, 53% KNO3, and 40% NaNO2, with a melting point of 142 degrees Celsius and an operating temperature range of 170 to 450 degrees Celsius. The Hitec ternary salt possesses suitable phase change temperature, high heat storage density, and good chemical stability. Therefore, using the Hitec ternary salt as a heat exchange medium can improve the safety and reliability of the heat storage and peak-shaving device 100 in the aforementioned thermal power unit.

[0071] This disclosure also provides a thermal power unit 200 thermal storage and peak shaving system, including the thermal power unit 200 and the aforementioned thermal power unit thermal storage and peak shaving device 100.

[0072] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0073] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0074] Furthermore, the various embodiments of the present disclosure can be arbitrarily combined with each other unless they contradict each other, and it should be understood that the same should be construed as being included in the disclosure of the present disclosure.

Claims

1. A heat storage peak shaving device (100) of a thermal power unit, characterized in that, The thermal power unit (200) comprises a boiler (210) and a deaerator (270), and the device comprises a first heat exchanger (111), a second heat exchanger (112), a third heat exchanger (113), a fourth heat exchanger (114), a fifth heat exchanger (115), a sixth heat exchanger (116), a high-temperature heat exchange medium storage tank (121), and a low-temperature heat exchange medium storage tank (122), wherein: The first heat exchanger (111) is used for communicating with the main steam outlet of the boiler (210) through a gas inlet, and is used for communicating with the cold reheat steam inlet of the boiler (210) through a gas outlet, and is further used for communicating with the gas inlet of the third heat exchanger (113) through the gas outlet, and is used for communicating with the third heat exchanger (113) through a heat exchange medium inlet, and is used for communicating with the high-temperature heat exchange medium storage tank (121) through a heat exchange medium outlet; The second heat exchanger (112) is used for communicating with the hot reheat steam outlet of the boiler (210) through a gas inlet, and is used for communicating with the cold reheat steam inlet of the boiler (210) through a gas outlet, and is used for communicating with the third heat exchanger (113) through a heat exchange medium inlet, and is used for communicating with the high-temperature heat exchange medium storage tank (121) through a heat exchange medium outlet; The third heat exchanger (113) is used for communicating with the cold reheat steam inlet of the boiler (210) through a gas outlet, and is used for communicating with the low-temperature heat exchange medium storage tank (122) through a heat exchange medium inlet, and is used for communicating with the boiler (210) through a feedwater outlet; The fourth heat exchanger (114) is used for communicating with the fifth heat exchanger (115) through a gas inlet, and is used for communicating with the cold reheat steam inlet of the boiler (210) through a gas outlet, and is used for communicating with the high-temperature heat exchange medium storage tank (121) through a heat exchange medium inlet, and is used for communicating with the fifth heat exchanger (115) through a heat exchange medium outlet; The fifth heat exchanger (115) is used for communicating with the sixth heat exchanger (116) through a heat exchange medium outlet, and is used for communicating with the sixth heat exchanger (116) through a feedwater inlet; The sixth heat exchanger (116) is used for communicating with the low-temperature heat exchange medium storage tank (122) through a heat exchange medium outlet, and is used for communicating with the deaerator (270) through a feedwater inlet.

2. The apparatus of claim 1, wherein, The first heat exchanger (111) and the second heat exchanger (112) are gas-liquid heat exchangers, and the third heat exchanger (113) is a condenser.

3. The apparatus of claim 1, wherein, The fourth heat exchanger (114) is a superheater, the fifth heat exchanger (115) is an evaporator, and the sixth heat exchanger (116) is a preheater.

4. The apparatus of claim 1, wherein, A pressure matcher (130) is further included, an inlet of the pressure matcher (130) is communicated with the gas outlet of the first heat exchanger (111) and the gas outlet of the second heat exchanger (112), and an outlet of the pressure matcher (130) is used for communicating with the cold reheat steam inlet of the boiler (210).

5. The apparatus of any one of claims 1-4, wherein, A cold salt pump (141) is further included, an inlet of which is communicated with an outlet of the low-temperature heat exchange medium storage tank (122), and an outlet of which is communicated with a heat exchange medium inlet of the third heat exchanger (113).

6. The apparatus of any one of claims 1-4, wherein, A first feed water pump (151) is further included, an inlet of which is communicated with a feed water outlet of the third heat exchanger (113), and an outlet of which is used for being communicated with a feed water inlet of the boiler (210).

7. The apparatus of any one of claims 1-4, wherein, A hot salt pump (142) is further included, an inlet of which is communicated with an outlet of the high-temperature heat exchange medium storage tank (121), and an outlet of which is communicated with a heat exchange medium inlet of the fourth heat exchanger (114).

8. The apparatus of any one of claims 1-4, wherein, A second feed water pump (152) is further included, an inlet of which is used for being communicated with a feed water outlet of the deaerator (270), and an outlet of which is communicated with a feed water inlet of the sixth heat exchanger (116).

9. The apparatus of any one of claims 1-4, wherein, The heat exchange medium is Hitec ternary salt.

10. A thermal energy storage peak shaving system for a thermal power unit (200), characterized in that, The thermal storage peak shaving device (100) of the thermal power generating unit (200) and the thermal power generating unit (200) as claimed in any one of claims 1-9 are included.

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