Heat storage peak regulation device and system of thermal power generating unit

Abstract

The invention relates to a heat storage peak regulation device and system of a thermal power generating unit, and relates to the technical field of power generation. According to the heat storage and peak regulation device of the thermal power generating unit, through the six heat exchangers and the high / low-temperature heat exchange medium storage tank, efficient storage and release of multiple waste heat loads of a boiler can be achieved, and therefore the deep peak regulation and peak regulation capacity of the thermal power generating unit can be improved. Specifically, heat is extracted from main steam and hot reheat steam of a boiler through a first heat exchanger and a second heat exchanger respectively, and the heat of the main steam is further extracted through a third heat exchanger. Excessive waste heat load of the boiler is converted into stored energy, steam output to a turbine by the boiler is reduced, output of a generator is reduced, and therefore deep peak regulation is achieved. The high-temperature heat exchange medium storage tank is used for storing heat, and guarantees are provided for follow-up peak operation of the thermal power generating unit. The fourth heat exchanger, the fifth heat exchanger and the sixth heat exchanger can efficiently release stored heat and output the heat to a steam turbine through cascade heat exchange, output of a generator is improved, and therefore peak is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power generation, and in particular to a heat storage peak-shaving device and system for a thermal power unit. Background Art

[0002] Thermal power generation is one of the pillar energy sources for my country's electricity supply. The key equipment of thermal power units includes boilers, steam turbines and generators. The boiler uses fossil fuels to burn and generate high-temperature and high-pressure main steam. The high-temperature and high-pressure main steam enters the steam turbine and performs work, driving the generator rotor to rotate. The generator converts mechanical energy into electrical energy and outputs it to the power grid.

[0003] However, as the scale of new energy installations continues to expand and the peak-to-valley difference in power grid load continues to intensify, thermal power units need to undertake greater peak-shaving tasks. During the low electricity consumption period or when the output of new energy is sufficient, thermal power units need to reduce load operation. However, even if the boiler of the thermal power unit is operated to the minimum stable combustion load, it may still not meet the peak-shaving demand. At this time, the thermal power unit can be assisted by the heat storage peak-shaving device to achieve deep peak-shaving. During the peak electricity consumption period or when the output of new energy is insufficient, the thermal power unit needs to increase the load operation. However, when the boiler reaches the rated load, it may still not be able to meet the peak demand. At this time, the heat storage peak-shaving device can be used to assist the thermal power unit to achieve the peak.

[0004] However, the ability of relevant heat storage peak-shaving devices to assist thermal power units in deep peak-shaving and peak-loading is limited. Therefore, improving the deep peak-shaving and peak-loading capabilities of thermal power units is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above problems, the present disclosure provides a heat storage peak-shaving device and system for a thermal power unit.

[0006] In a first aspect, the present disclosure provides a heat storage peak-shaving device for 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: The first heat exchanger has a gas inlet for communicating with the main steam outlet of the boiler, a gas outlet for communicating with the cold reheat steam inlet of the boiler, a gas outlet for communicating with the gas inlet of the third heat exchanger, a heat exchange medium inlet for communicating with the heat exchange medium outlet of the third heat exchanger, and a heat exchange medium outlet for communicating with the inlet of the high-temperature heat exchange medium storage tank; The gas inlet of the second heat exchanger is used to communicate with the hot reheat steam outlet of the boiler, the gas outlet is used to communicate with the cold reheat steam inlet of the boiler, the heat exchange medium inlet is communicated with the heat exchange medium outlet of the third heat exchanger, and the heat exchange medium outlet is communicated with the inlet of the high-temperature heat exchange medium storage tank; The third heat exchanger has a gas outlet for communicating with the cold reheat steam inlet of the boiler, a heat exchange medium inlet for communicating with the outlet of the low-temperature heat exchange medium storage tank, and a feed water outlet for communicating with the feed water inlet of the boiler; The fourth heat exchanger, whose gas inlet is connected to the gas outlet of the fifth heat exchanger, whose gas outlet is used to communicate with the cold reheat steam inlet of the boiler, whose heat exchange medium inlet is connected to the outlet of the high-temperature heat exchange medium storage tank, and whose heat exchange medium outlet is connected to the heat exchange medium inlet of the fifth heat exchanger; The heat exchange medium outlet of the fifth heat exchanger is connected to the heat exchange medium inlet of the sixth heat exchanger, and the water supply inlet of the fifth heat exchanger is connected to the water supply outlet of the sixth heat exchanger; The heat exchange medium outlet of the sixth heat exchanger is communicated with the inlet of the low-temperature heat exchange medium storage tank, and the water supply inlet of the sixth heat exchanger is used to communicate with the water supply outlet of the deaerator.

[0007] Optionally, the first heat exchanger and the second heat exchanger are gas-liquid heat exchangers, and the third heat exchanger is a condenser.

[0008] Optionally, the fourth heat exchanger is a superheater, the fifth heat exchanger is an evaporator, and the sixth heat exchanger is a preheater.

[0009] Optionally, a pressure matcher is further included, whose inlet is connected to the gas outlet of the first heat exchanger and the gas outlet of the second heat exchanger, and whose outlet is used to connect to the cold reheat steam inlet of the boiler.

[0010] Optionally, a cold salt pump is further included, whose inlet is connected to the outlet of the low-temperature heat exchange medium storage tank, and whose outlet is connected to the heat exchange medium inlet of the third heat exchanger.

[0011] Optionally, a first feed water pump is further included, whose inlet is connected to the feed water outlet of the third heat exchanger, and whose outlet is used to communicate with the feed water inlet of the boiler.

[0012] Optionally, a hot salt pump is further included, whose inlet is connected to the outlet of the high-temperature heat exchange medium storage tank, and whose outlet is connected to the heat exchange medium inlet of the fourth heat exchanger.

[0013] Optionally, a second feed water pump is further included, whose inlet is used to communicate with the feed water outlet of the deaerator, and whose outlet is communicated with the feed water inlet of the sixth heat exchanger.

[0014] Optionally, the heat exchange medium is Hitec ternary salt.

[0015] In a second aspect, the present disclosure further provides a heat storage peak-shaving system for a thermal power unit, comprising a thermal power unit and a heat storage peak-shaving device for the thermal power unit as described in any one of the first aspects.

[0016] In the above technical solution, the heat storage peak-shaving device of the thermal power unit can realize the efficient storage and release of the excess heat load of the boiler through the arrangement of six groups of heat exchangers and high and low temperature heat exchange medium storage tanks, thereby improving the deep peak-shaving and peak capacity of the thermal power unit. Specifically, heat is extracted from the main steam and hot reheat steam of the boiler respectively through the first heat exchanger and the second heat exchanger, and the third heat exchanger further extracts the heat of the main steam. This multi-stage heat exchange design can make heat recovery more sufficient, convert the excess heat load of the boiler into energy storage, reduce the steam output of the boiler to the turbine, and reduce the output of the generator, thereby achieving deep peak-shaving. The high-temperature heat exchange medium storage tank is used to store heat to provide guarantee for the subsequent peak operation of the thermal power unit. The fourth, fifth, and sixth heat exchangers can efficiently release the stored heat and output it to the turbine through cascade heat exchange, increase the output of the generator, and thus achieve the peak.

[0017] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 is a structural diagram of a heat storage peak-shaving device of a thermal power unit according to an exemplary embodiment; Figure 2 It is a structural diagram of a heat storage peak-shaving device of a thermal power unit according to another exemplary embodiment.

[0019] Description of Reference Numerals A heat storage and peak-shaving device 100 of a thermal power unit, 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, a low-temperature heat exchange medium storage tank 122, a pressure matcher 130, a cold salt pump 141, a first feed water pump 151, a condensate 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. DETAILED DESCRIPTION

[0020] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0021] Herein, the terms "first", "second", etc. are only used to distinguish one element from another element, and do not require or imply any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa.

[0022] Moreover, the term "comprising" is intended to cover a non-exclusive inclusion, such that a structure, apparatus, or device that includes a list of elements includes not only those elements but also other elements not explicitly listed or elements inherent to such structure, apparatus, or device.

[0023] Figure 1 FIG. 1 is a structural diagram of a thermal storage peak-shaving device 100 of a thermal power unit according to an exemplary embodiment. 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, its gas inlet is used to communicate with the main steam outlet of the boiler 210, and its gas outlet is used to communicate with the cold reheat steam inlet of the boiler 210, The gas outlet of the second heat exchanger 112 is also connected to the gas inlet of the third heat exchanger 113, the heat exchange medium inlet of the third heat exchanger 113 is connected to the heat exchange medium outlet of the third heat exchanger 113, and the heat exchange medium outlet is connected to the inlet of the high-temperature heat exchange medium storage tank 121; the gas inlet of the second heat exchanger 112 is used to communicate with the hot reheat steam outlet of the boiler 210, and the gas outlet is used to communicate with the cold reheat steam inlet of the boiler 210, and the heat exchange medium inlet is connected to the heat exchange medium outlet of the third heat exchanger 113, and the heat exchange medium outlet is connected to the inlet of the high-temperature heat exchange medium storage tank 121. The gas outlet of the third heat exchanger 113 is connected to the inlet of the high-temperature heat exchange medium storage tank 121; the gas outlet of the third heat exchanger 113 is used to communicate with the cold reheat steam inlet of the boiler 210, the heat exchange medium inlet is connected to the outlet of the low-temperature heat exchange medium storage tank 122, and the feed water outlet is used to communicate with the feed water inlet of the boiler 210; the gas inlet of the fourth heat exchanger 114 is connected to the gas outlet of the fifth heat exchanger 115, and the gas outlet is used to communicate with the cold reheat steam inlet of the boiler 210, and the heat exchange medium inlet is connected to the outlet of the low-temperature heat exchange medium storage tank 122, and the feed water outlet is used to communicate with the feed water inlet of the boiler 210. The heat medium inlet of the heat exchanger 115 is connected to the outlet of the high-temperature heat exchange medium storage tank 121, and the heat exchange medium outlet is connected to the heat exchange medium inlet of the fifth heat exchanger 115; the heat exchange medium outlet of the fifth heat exchanger 115 is connected to the heat exchange medium inlet of the sixth heat exchanger 116, and the water supply inlet is connected to the water supply outlet of the sixth heat exchanger 116; the heat exchange medium outlet of the sixth heat exchanger 116 is connected to the inlet of the low-temperature heat exchange medium storage tank 122, and the water supply inlet is used to connect to the water supply outlet of the deaerator 270.

[0024] First, the thermal power plant 200 will be described. 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 feed water pump 280 and a high-pressure heater 262. The boiler 210 generates high-temperature and high-pressure steam by heating the feed water by burning fossil fuels such as coal. The high-pressure cylinder 221 first receives the highest-parameter steam 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 three cylinders of 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 uses cooling water to condense the low-pressure steam discharged from the steam turbine into water. The condensate pump 250 delivers the condensate in the condenser 240 to the low-pressure heater 261. The low-pressure heater 261 heats the condensate using the low-pressure steam extracted from the steam turbine. The heated condensate is sent to the deaerator 270. The deaerator 270 degasses the feed water to remove dissolved gases in the water. The deaerator 270 also extracts low-pressure steam from the medium-pressure cylinder 222 to heat the feed water to the saturation temperature under the pressure of the deaerator 270. The feed water pump 280 delivers the deoxygenated feed water to the high-pressure heater 262. The high-pressure heater 262 heats the feed water using the medium- and high-pressure steam extracted from the steam turbine. The heated feed water is sent back to the boiler 210 for the next power generation cycle.

[0025] The boiler 210 of the thermal power unit 200 includes an economizer, a reheater and a superheater. Among them, the economizer is located in the flue gas outlet of the boiler 210, and is used to absorb the remaining heat in the flue gas. The economizer uses this heat to heat the feed water again to improve the overall thermal efficiency. The feed water inlet of the economizer is connected to the feed water outlet of the high-pressure heater. The reheater is located on the heating surface pipe of the boiler 210, and is used to reheat the steam discharged from the high-pressure cylinder 221. The superheater is located on the heating surface pipe of the boiler 210, and by absorbing the heat from the furnace and the flue, the steam reaches a higher temperature and pressure to form superheated steam.

[0026] Secondly, the technical terms in the heat storage and peak-shaving device 100 of the above-mentioned thermal power unit are explained. The first to sixth heat exchangers refer to equipment for heat exchange 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 medium circulating in the heat storage and peak-shaving device 100 of the above-mentioned 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 the temperature of the heat exchange medium stored in the low-temperature heat exchange medium storage tank 122.

[0027] High-temperature main steam refers to high-temperature and high-pressure steam output from the outlet of the superheater of the boiler 210, and 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 entering the reheater. Hot reheat steam refers to high-temperature steam after the cold reheat steam is heated by the reheater of the boiler 210. Feed water refers to water supplied to the thermal storage peak-shaving device 100 of the boiler 210 / the above-mentioned thermal power unit.

[0028] Based on the above-mentioned thermal power unit 200, the peak heat storage process and the peak heat release process that can be performed by the thermal storage peak shaving device 100 of the thermal power unit are explained.

[0029] The peak-shaving heat storage process is used when the boiler 210 is at the lowest stable combustion load and the output of the generator 230 needs to continue to be reduced. It refers to the process of transferring the excess heat load of the boiler 210 to the heat exchange medium through the heat exchanger of the above-mentioned heat storage peak-shaving device and storing it to achieve deep peak-shaving.

[0030] The main path of the peak-shaving heat storage process is: the main steam generated by the boiler 210 enters the first heat exchanger 111, the reheated steam generated by the furnace enters the second heat exchanger 112, and the low-temperature heat exchange medium flows from the low-temperature heat exchange medium storage tank 122 through the first, second, and third heat exchangers and finally reaches the high-temperature heat exchange medium storage tank 121.

[0031] 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 relatively low-temperature heat exchange medium in the first heat exchanger 111 to form relatively low-temperature steam and relatively high-temperature heat exchange medium. (3) A portion of the relatively low-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 portion of the relatively low-temperature steam enters the third heat exchanger 113 to continue to exchange heat with the low-temperature heat exchange medium to form water and relatively low-temperature heat exchange medium. The water output from the third heat exchanger 113 is transported to the feed water inlet of the boiler 210 as the feed water of the boiler 210. Specifically, the water output from the third heat exchanger 113 is transported to the feed water inlet of the economizer of the boiler 210 as the feed water of the boiler 210.

[0032] The conversion process of 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 to form 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, returns to the cold reheat steam inlet of the reheater.

[0033] 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 relatively low-temperature steam in the third heat exchanger 113 to form a relatively low-temperature heat exchange medium and water. (3) A portion of the relatively low-temperature medium enters the first heat exchanger 111 to exchange heat with the main steam to form a portion of high-temperature heat exchange medium and relatively low-temperature steam. (4) Another portion of the relatively low-temperature medium enters the second heat exchanger 112 to exchange heat with the hot reheat steam to form another portion of high-temperature heat exchange medium and low-temperature steam. (5) The two portions of high-temperature heat exchange medium finally enter the high-temperature heat exchange medium storage tank 121 for storage.

[0034] The peak heat release process is used when the boiler 210 is at rated load and the output of the generator 230 needs to be further increased. It refers to the process of transferring the stored heat of the above-mentioned heat storage peak-shaving device from the heat exchange medium to the high-temperature steam through the heat exchanger and delivering it to the thermal power unit 200 to achieve the peak. The specific process of peak heat release is as follows.

[0035] The main path of peak load storage is: the high-temperature heat exchange medium is released from the high-temperature heat exchange medium storage tank 121, the high-temperature heat exchange medium 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.

[0036] 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 a higher-temperature heat exchange medium and high-temperature steam. (3) The higher-temperature heat exchange medium enters the fifth heat exchanger 115 to exchange heat with the high-temperature feed water to form a lower-temperature heat exchange medium and a higher-temperature steam. (4) The lower-temperature heat exchange medium enters the sixth heat exchanger 116 to exchange heat with the low-temperature feed water to form a low-temperature heat exchange medium and a high-temperature feed water. (5) The low-temperature heat exchange medium is stored in the low-temperature heat exchange medium storage tank 122.

[0037] The conversion process of 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, and serves as the feed water for the heat storage peak-shaving device 100 of the above-mentioned 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 enters the fifth heat exchanger 115 to exchange heat with the higher temperature heat exchange medium to form higher temperature steam and lower temperature heat exchange medium. (4) Finally, it passes through other heat exchangers and enters the boiler 210.

[0038] It should be understood that the main steam and the hot reheat steam have the same temperature, about 540-600 degrees Celsius, and can both be used for heat storage. The heat storage peak-shaving device 100 of the above-mentioned thermal power unit extracts these two parts of steam for heat storage, which can double absorb the residual load heat of the boiler 210 and double reduce the output of the generator 230, thereby achieving a greater degree of deep peak regulation. Because the main steam has a higher pressure than the hot reheat steam, a part of the main steam can be heat-exchanged again, and the low-temperature heat exchange medium can be preheated to fully extract the heat in the main steam. A part of the main steam forms water after heat exchange again, and this part of water is added to the boiler 210 to balance the steam-water circulation system of the boiler 210.

[0039] Since the water at the outlet of the deaerator 270 has been freed of oxygen and other harmful gases, a portion of the feed water of the boiler 210 is drawn out from the deaerator 270 as the feed water of the heat storage peak-shaving device 100 of the above-mentioned thermal power unit, which can prevent the corrosion of the heat storage peak-shaving device 100 of the above-mentioned thermal power unit, thereby increasing its service life. The high-temperature steam output by the fourth heat exchanger 114 is used to increase the output of the thermal power unit 200. The high-temperature steam is transported to the cold reheat steam inlet of the boiler 210. Specifically, the high-temperature steam is used to be transported to the cold reheat steam inlet of the reheater. The high-temperature steam is mixed and heated with the remaining steam in the reheater to generate hot reheat steam. The hot reheat steam is sequentially transported to the medium-pressure cylinder 222 and the low-pressure cylinder 223 to perform work, thereby increasing the output of the thermal power unit 200.

[0040] According to the above technical solution, the heat storage and peak-shaving device 100 of the thermal power unit can realize the 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 exchange medium storage tanks 122, thereby improving the deep peak-shaving and peak capacity of the thermal power unit 200. Specifically, heat is extracted from the main steam and hot reheat steam of the boiler 210 respectively through the first heat exchanger 111 and the second heat exchanger 112, and the third heat exchanger 113 further extracts the heat of the main steam. This multi-stage heat exchange design can make heat recovery more sufficient, convert the excess heat load of the boiler 210 into energy storage, reduce the steam output of the boiler 210 to the turbine, and reduce the output of the generator 230, thereby achieving deep peak-shaving. The high-temperature heat exchange medium storage tank 121 is used to store heat to provide guarantee for the subsequent peak operation of the thermal power unit 200. The fourth, fifth and sixth heat exchangers can release the stored heat efficiently through cascade heat exchange and output it to the steam turbine, thereby increasing the output of the generator 230 and achieving peak power.

[0041] The heat storage peak-shaving device may also include a first valve, which is arranged between the gas outlet of the superheater and the gas inlet of the first heat exchanger 111, and is used to control whether the main steam enters the heat storage peak-shaving device for heat storage. The heat storage peak-shaving device may also include a second valve, which is arranged between the gas outlet of the reheater and the gas inlet of the second heat exchanger 112, and is used to control whether the hot reheat steam enters the heat storage peak-shaving device for heat storage. The heat storage peak-shaving device may also include a third valve, which is arranged between the feed water inlet of the economizer and the gas outlet of the fourth heat exchanger 114, and is used to control whether the high-temperature steam is released into the thermal power unit 200 for heat release.

[0042] In one embodiment, the first heat exchanger 111 and the second heat exchanger 112 may be gas-liquid heat exchangers, and the third heat exchanger 113 may be a condenser.

[0043] It should be understood that the first heat exchanger 111 performs heat exchange between the gaseous state of the main steam and the liquid state of the heat exchange medium, so it can be a gas-liquid heat exchanger. Because the temperature and pressure of the main steam are high, in the actual selection, a gas-liquid heat exchanger that can withstand high temperature and high pressure and maintain effective separation of the gas phase and the liquid phase should be selected as the first heat exchanger 111. The second heat exchanger 112 performs heat exchange between the gaseous state of the hot reheat steam and the liquid state of the heat exchange medium, so it can also be a gas-liquid heat exchanger. Because the temperature and pressure of the hot reheat steam are high, in the actual selection, a gas-liquid heat exchanger that can withstand high temperature and high pressure and maintain effective separation of the gas phase and the liquid phase should also be selected as the second heat exchanger 112. The third heat exchanger 113 performs heat exchange to completely condense the steam into water, so it can be a condenser. The condenser can fully recover the potential heat in the steam and reduce energy loss.

[0044] In one embodiment, the fourth heat exchanger 114 may be a superheater, the fifth heat exchanger 115 may be an evaporator, and the sixth heat exchanger 116 may be a preheater.

[0045] It should be understood that the sixth heat exchanger 116 is used to preheat the outlet feed water of the deaerator 270, so it can be a preheater. The preheater can use lower-grade heat to increase the temperature of the feed water and reduce the load of the fifth and fourth heat exchangers. The fifth heat exchanger 115 is used to perform the gas-liquid phase change process of the feed water, so it can be an evaporator. The preheated feed water can be converted into saturated steam by the evaporator, making full use of the heat of the high-temperature heat exchange medium. The sixth heat exchanger 116 is used to heat the steam to a superheated state, so it can be a superheater. The superheater can ensure that the steam reaches a sufficient degree of superheat to enter the reheat steam inlet of the reheater. The above three heat exchangers can achieve a step-by-step utilization of heat and fully extract the heat from the high-temperature heat exchange medium.

[0046] Figure 2FIG. 1 is a structural diagram of a thermal storage peak-shaving device 100 of a thermal power unit according to another exemplary embodiment. Figure 2 As shown, the device may further include a pressure matcher 130 , whose inlet is connected to both the gas outlet of the first heat exchanger 111 and the gas outlet of the second heat exchanger 112 , and whose outlet is used to connect to the cold reheat steam inlet of the boiler 210 .

[0047] It should be understood that the pressures of the steam output from the first heat exchanger 111 and the second heat exchanger 112 are different and may not meet the pressure requirements of the reheater for steam, so a pressure matcher 130 is required to adjust the steam pressures of the two parts. The pressure matcher 130 can make the steam output from the first heat exchanger 111 and the second heat exchanger 112 mix smoothly, prevent steam backflow and pressure fluctuations, and reduce the impact on the cold reheat steam inlet of the reheater.

[0048] In one embodiment, if Figure 2 As shown, the device may further include a cold salt pump 141 , whose inlet is connected to the outlet of the low-temperature heat exchange medium storage tank 122 , and whose outlet is connected to the heat exchange medium inlet of the third heat exchanger 113 .

[0049] 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 required to extract the low-temperature heat exchange medium from the storage tank and transport it to the corresponding heat exchanger. The heat exchange medium is usually a low-temperature molten salt. Therefore, a cold salt pump 141 can be set between the low-temperature heat exchange medium storage tank 122 and the third heat exchanger 113 to drive and transport the low-temperature heat exchange medium to ensure the circulation of the heat exchange medium.

[0050] In one embodiment, if Figure 2 As shown, the device may further include a first feed water pump 151 , an inlet of which is connected to the feed water outlet of the third heat exchanger 113 , and an outlet of which is used to be connected to the feed water inlet of the boiler 210 .

[0051] It should be understood that the water output from the third heat exchanger 113 is transported to the water supply system of the boiler 210, which needs to overcome the pressure of the water supply system of the boiler 210. Therefore, a first water supply pump 151 can be provided between the third heat exchanger 113 and the boiler 210. The first water supply pump 151 can also ensure the stability of the water flow rate. And by adjusting the first water supply pump 151, the water supply pressure requirement of the boiler 210 can be met.

[0052] In one embodiment, if Figure 2As shown, the device may also include a condensate storage tank 1511, an electric regulating valve 1512 and an electric 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 the outlet is connected to the inlet of the first water supply pump 151; the inlet of the electric regulating valve 1512 is connected to the outlet of the first water supply pump 151, and the outlet is connected to the inlet of the electric valve 1513; the outlet of the electric valve 1513 is connected to the second inlet of the condensate storage tank 1511.

[0053] Here, the condensed water storage tank 1511 is a container for storing condensed water. The electric regulating valve 1512 has the function of finely adjusting the opening, which can carefully control the flow of condensed water flowing through. However, the sealing performance of the valve in the fully closed state is relatively low. Although the electric valve 1513 cannot finely adjust the opening 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 condensed water.

[0054] It should be understood that in the early and late stages of the operation of the heat storage peak-shaving device, the third heat exchanger outputs less condensed water, which may cause the first water supply pump 151 to fail to start and operate normally. This is because the condensed water flow and pressure at this time may not meet the working requirements of the first water supply pump 151. Specifically, the condensed water flow cannot be lower than the minimum flow of the first water supply pump 151, and the condensed water pressure cannot be lower than the minimum pressure requirement of the pump.

[0055] Therefore, the condensed water storage tank 1511 can be used to store condensed water to form sufficient water pressure and water flow to meet the working conditions of the first water supply pump 151. When the condensed water in the condensed water storage tank 1511 is about to fail to meet the working requirements of the first water supply pump 151, the electric valve 1513 can be opened, and the flow rate can be adjusted through the electric regulating valve 1512, so that the condensed water output by the first water supply pump 151 flows back to the condensed water storage tank 1511, and the minimum circulation flow rate is maintained to meet the working requirements of the first water supply pump 151.

[0056] In one embodiment, if Figure 2 As shown, the device may further include a hot salt pump 142 , whose inlet is connected to the outlet of the high-temperature heat exchange medium storage tank 121 , and whose outlet is connected to the heat exchange medium inlet of the fourth heat exchanger 114 .

[0057] It should be understood that the high-temperature heat exchange medium is stored in the high-temperature heat exchange medium storage tank 121, and an external force is required to extract the high-temperature heat exchange medium from the storage tank and transport it to the corresponding heat exchanger. The heat exchange medium is usually a high-temperature molten salt. Therefore, a hot salt pump 142 can be set between the high-temperature heat exchange medium storage tank 121 and the fourth heat exchanger 114 to drive and transport the high-temperature heat exchange medium to ensure the circulation of the heat exchange medium.

[0058] In one embodiment, if Figure 2 As shown, the device may further include a second feed water pump 152 , an inlet of which is used to communicate with the feed water outlet of the deaerator 270 , and an outlet of which is communicated with the feed water inlet of the sixth heat exchanger 116 .

[0059] It should be understood that the feed water at the outlet of the deaerator 270 is transported to the thermal storage peak-shaving device 100 of the thermal power unit, so a second feed water pump 152 can be provided between the sixth heat exchanger 116 and the deaerator 270. The second feed water pump 152 can also ensure the stability of the water flow rate. And by adjusting the second feed water pump 152, the feed water pressure requirement of the thermal storage peak-shaving device 100 of the thermal power unit can be met.

[0060] In one embodiment, the heat exchange medium may be Hitec ternary salt.

[0061] Here, 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 of 170 degrees Celsius to 450 degrees Celsius. Hitec ternary salt has a suitable phase change temperature, high heat storage density and good chemical stability. Therefore, using Hitec ternary salt as a heat exchange medium can improve the safety and reliability of the thermal storage peak-shaving device 100 of the above-mentioned thermal power unit.

[0062] The present disclosure further provides a heat storage peak-shaving system for a thermal power unit 200, comprising the thermal power unit 200 and the heat storage peak-shaving device 100 of the thermal power unit.

[0063] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0064] 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, the present disclosure will not further describe various possible combinations.

[0065] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A heat storage peak-shaving device (100) for 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), its gas inlet is used to communicate with the main steam outlet of the boiler (210), its gas outlet is used to communicate with the cold reheat steam inlet of the boiler (210), its gas outlet is also connected to the gas inlet of the third heat exchanger (113), its heat exchange medium inlet is connected to the heat exchange medium outlet of the third heat exchanger (113), and its heat exchange medium outlet is connected to the inlet of the high-temperature heat exchange medium storage tank (121); The second heat exchanger (112) has a gas inlet for communicating with the hot reheat steam outlet of the boiler (210), a gas outlet for communicating with the cold reheat steam inlet of the boiler (210), a heat exchange medium inlet for communicating with the heat exchange medium outlet of the third heat exchanger (113), and a heat exchange medium outlet for communicating with the inlet of the high-temperature heat exchange medium storage tank (121); The third heat exchanger (113) has a gas outlet for communicating with a cold reheat steam inlet of the boiler (210), a heat exchange medium inlet for communicating with an outlet of the low-temperature heat exchange medium storage tank (122), and a feed water outlet for communicating with a feed water inlet of the boiler (210); The fourth heat exchanger (114) has a gas inlet in communication with a gas outlet of the fifth heat exchanger (115), a gas outlet in communication with a cold reheat steam inlet of the boiler (210), a heat exchange medium inlet in communication with an outlet of the high-temperature heat exchange medium storage tank (121), and a heat exchange medium outlet in communication with a heat exchange medium inlet of the fifth heat exchanger (115); The heat exchange medium outlet of the fifth heat exchanger (115) is in communication with the heat exchange medium inlet of the sixth heat exchanger (116), and the water supply inlet of the fifth heat exchanger (115) is in communication with the water supply outlet of the sixth heat exchanger (116); The heat exchange medium outlet of the sixth heat exchanger (116) is in communication with the inlet of the low-temperature heat exchange medium storage tank (122), and the water supply inlet is used to communicate with the water supply outlet of the deaerator (270).

2. The device according to claim 1, characterized in that 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 device according to claim 1, characterized in that 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 device according to claim 1, characterized in that It also includes a pressure matcher (130), whose inlet is connected to the gas outlet of the first heat exchanger (111) and the gas outlet of the second heat exchanger (112), and whose outlet is used to communicate with the cold reheat steam inlet of the boiler (210).

5. The device according to any one of claims 1 to 4, characterized in that: It also includes a cold salt pump (141), the inlet of which is connected to the outlet of the low-temperature heat exchange medium storage tank (122), and the outlet of which is connected to the heat exchange medium inlet of the third heat exchanger (113).

6. The device according to any one of claims 1 to 4, characterized in that: It also includes a first feed water pump (151), whose inlet is connected to the feed water outlet of the third heat exchanger (113), and whose outlet is used to communicate with the feed water inlet of the boiler (210).

7. The device according to any one of claims 1 to 4, characterized in that: It also includes 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).

8. The device according to any one of claims 1 to 4, characterized in that: It also includes a second feed water pump (152), whose inlet is used to communicate with the feed water outlet of the deaerator (270), and whose outlet is connected to the feed water inlet of the sixth heat exchanger (116).

9. The device according to any one of claims 1 to 4, characterized in that: The heat exchange medium is Hitec ternary salt.

10. A thermal storage peak-shaving system for a thermal power unit (200), characterized in that: It comprises a thermal power unit (200) and a heat storage peak regulation device (100) for the thermal power unit according to any one of claims 1 to 9.

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