CN114704815B - Steam heat storage system - Google Patents

Abstract

The invention discloses a steam heat storage system. The steam heat storage system includes a boiler, a heat exchanger, a mixer, a molten salt energy storage component and a water pump. The boiler has a flue and a steam port, and the heat exchanger is connected to the flue and the steam port respectively. The steam port is connected so that the flue gas and steam in the boiler flow into the heat exchanger respectively and heat is exchanged in the heat exchanger to increase the temperature of the flue gas. The mixer is connected with the steam port so that the steam flowing out of the boiler flows into the mixer. , the mixer is connected to the heat exchanger, so that the steam after heat exchange by the heat exchanger flows into the mixer, and the mixer is used to mix the steam to reduce the temperature of the steam to a first preset value. The steam heat storage system of the present invention has the advantages of simple structure, high energy utilization rate, and low cost.

Description

Steam heat storage system

Technical field

The present invention relates to the technical field of heat storage and peak regulation in coal-fired power plants, and specifically, to a steam heat storage system.

Background technique

Our country is a large coal-burning country, and the installed capacity of coal-fired generators ranks first in the world. In order to improve the power grid's ability to absorb clean energy such as wind power and photovoltaics, coal-fired units are gradually carrying out flexibility transformation, through technical transformation and optimized operation. , the minimum output of most units has been reduced from about 50% of the rated load to 30-40% of the rated load. However, with the rapid development of clean energy such as wind power and photovoltaics, and in the context of carbon peaking and carbon neutrality, the flexibility transformation of existing coal power units alone is far from being able to meet the grid's demand for peak shaving and frequency modulation power. Configuring a certain proportion of energy storage in coal-fired power plants has become the main adjustment method.

Among related technologies, peak shaving capabilities are poor and energy storage efficiency is low.

Contents of the invention

The present invention is based on the inventor's discovery and understanding of the following facts and problems:

Among related technologies, the main energy storage technologies include: battery energy storage, hot water energy storage, compressed air energy storage, flywheel energy storage, molten salt energy storage, etc. At present, except for battery energy storage and electric heating energy storage, which have certain applications in coal-fired power plants, there are few reports on the application of other energy storage methods. Take electric heating energy storage as an example. At present, electric heating storage systems are mainly configured. That is, during the low period of electricity consumption, part of the electric energy generated by thermal power units is used to store heat through electric heating storage media for building heating. Due to this depth The peak shaving method goes through two energy conversion processes: heat → electricity → heat. The energy conversion efficiency is low. At the same time, building heating is seasonal and cannot achieve deep peak shaving throughout the year. Therefore, from the perspective of energy conversion efficiency, the peak-shaving method of steam heat storage is from heat to heat. Regardless of whether it is used for heating or returned to the thermal system for power generation, its efficiency is higher than that of electric heating energy storage.

In addition, during low-load peak-shaving operation of the unit, as the load decreases and the amount of coal burned decreases, the flue temperature at the inlet of the denitration device will gradually drop below 300°C, and the denitration catalyst will face the risk of deactivation, and various technologies need to be adopted Modification measures are taken to increase the inlet smoke temperature of the denitrification device. The main technical transformation measures to improve the inlet flue temperature of the denitrification device include economizer external flue gas bypass modification, economizer water supply bypass modification, economizer classification modification, hot water recycling modification, gas supplementary combustion heating modification, etc.

The invention patent application number 202111230323.6 discloses an energy storage peak-shaving system suitable for heating molten salt by steam in reheating units. It mainly extracts superheated steam from the boiler and enters the molten salt energy storage system for heat storage to reduce the unit load. , and at the same time, in order to avoid over-temperature of the reheater, part of the hot resteam with working capacity is injected back to the cold reheat through high pressure, mixed with the high-pressure cylinder exhaust and then re-enters the reheater, resulting in low energy conversion efficiency.

The utility model with patent number CN202022039229. The main steam has strong power, but the direct extraction for heating flue gas energy conversion efficiency is low, and there is a risk of overtemperature of the reheater.

The present invention aims to solve one of the technical problems in the related art, at least to a certain extent. To this end, embodiments of the present invention propose a steam heat storage system with high energy storage efficiency and high peak-shaving conversion rate.

The steam heat storage system of the embodiment of the present invention includes: a boiler, the boiler has a flue and a steam port; a heat exchanger, the heat exchanger is connected to the flue and the steam port respectively, so that the inside of the boiler can The flue gas and steam flow into the heat exchanger respectively and exchange heat in the heat exchanger to increase the temperature of the flue gas; a mixer, the mixer is connected to the steam port so as to pass through the The steam flowing out of the boiler flows into the mixer, and the mixer is connected to the heat exchanger, so that the steam after heat exchange by the heat exchanger flows into the mixer, and the mixer is used to mix the steam to make The temperature of the steam is reduced to a first preset value; a molten salt energy storage component and a water pump. The steam heat storage system has a first state and a second state. In the first state, the molten salt energy storage component It is connected to the mixer so that the steam mixed by the mixer flows into the molten salt energy storage component to store energy in the molten salt energy storage component. In the second state, the water pump and the The molten salt energy storage component is connected, so that the condensed water flows into the molten salt energy storage component through the water pump and exchanges heat with the molten salt in the molten salt energy storage component to release energy from the molten salt energy storage component.

The steam heat storage system in the embodiment of the present invention is equipped with a boiler, a heat exchanger, a mixer, a molten salt energy storage component and a water pump, and organically combines heat storage peak regulation and steam heating flue gas to achieve wide-load denitration, which not only solves the problem The problem of low smoke temperature at the inlet of the denitration device under low load ensures the safe operation of the denitration catalyst; the unit load is reduced through extraction heat storage, which improves the unit's deep peak-shaving capability; at the same time, through the cascade utilization of high-temperature steam, The energy conversion efficiency of the molten salt heat storage system is improved.

In some embodiments, the steam heat storage system further includes a liquid storage tank. In the first state, the liquid storage tank is connected to the molten salt energy storage component so as to be exchanged via the molten salt energy storage component. The heated condensation water flows into the liquid storage tank.

In some embodiments, the steam heat storage system further includes a temperature adjustment component, which is connected to the liquid storage tank and is used to transport condensed water to the liquid storage tank to adjust the temperature inside the liquid storage tank. temperature.

In some embodiments, in the second state, the liquid storage tank is connected to the water pump, so that the condensed water in the liquid storage tank flows into the molten salt energy storage component through the water pump.

In some embodiments, the steam heat storage system further includes a steam header, the steam header is connected to the molten salt energy storage component, so that the steam after being heat exchanged by the molten salt energy storage component flows into the Steam header, the steam header is used to replace the auxiliary steam or extraction steam of the unit.

In some embodiments, the temperature of the steam flowing out of the mixer is a first temperature, the temperature of the molten salt in the molten salt energy storage component is a second temperature, and the temperature is between the first temperature and the second temperature. When the difference is less than the second preset value, the mixer is connected to the steam header, so that the steam mixed by the mixer flows into the steam header.

In some embodiments, the steam heat storage system further includes a heat supply pipeline. In the second state, the heat supply pipeline is connected to the molten salt energy storage component so as to release energy through the molten salt energy storage component. The heated steam flows into the heating pipe, and the heating pipe is used to heat the client.

In some embodiments, the temperature of the steam flowing out of the mixer is a first temperature, the temperature of the molten salt in the molten salt energy storage component is a second temperature, and the temperature is between the first temperature and the second temperature. When the difference is less than the second preset value, the mixer is connected to the heating pipe, so that the steam mixed by the mixer flows into the heating pipe.

In some embodiments, the steam heat storage system further includes a deaerator, which is connected to the water pump to remove oxygen from the condensed water flowing into the water pump. In the second state, the The molten salt energy storage component is connected to the deaerator, so that the steam after energy release and heat exchange by the molten salt energy storage component flows into the deaerator.

In some embodiments, the molten salt energy storage component includes a plurality of molten salt energy storage units, and the plurality of molten salt energy storage units are connected in sequence, so that the steam and the condensed water are stored in the molten salt energy storage unit. Heat is exchanged step by step within the components.

Description of the drawings

Figure 1 is a schematic structural diagram of a steam heat storage system according to an embodiment of the present invention.

Reference signs:

Steam heat storage system 100;

Boiler 1; heat exchanger 2; first valve 3; mixer 4; second valve 5; molten salt energy storage component 6; third valve 7; steam header 8; fourth valve 9; liquid storage tank 10; Five valves 11; first water pump 12; condensate heater 13; water pump 14; sixth valve 15; deaerator 16; ninth valve 17; seventh valve 18; eighth valve 19; heating pipe 20.

Detailed ways

Embodiments of the invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and are not to be construed as limiting the present invention.

The steam heat storage system according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in Figure 1, the steam heat storage system of the embodiment of the present invention includes a boiler 1, a heat exchanger 2, a mixer 4, a molten salt energy storage component 6 and a water pump 14.

The boiler 1 has a flue (not shown in the figure) and a steam port (not shown in the figure). Specifically, the flue gas in the boiler 1 flows out from the flue, and the steam in the boiler 1 flows out from the steam port.

The heat exchanger 2 is connected to the flue and the steam port respectively, so that the flue gas and steam in the boiler 1 flow into the heat exchanger 2 respectively and exchange heat in the heat exchanger 2 to increase the temperature of the flue gas. Specifically, the heat exchanger 2 includes a first inlet (not shown in the figure), a second inlet (not shown in the figure), a first outlet (not shown in the figure) and a second outlet (not shown in the figure). ), the first inlet is connected to the flue, the flue gas in the boiler 1 flows into the first inlet, the second inlet is connected to the steam port, the steam in the boiler 1 is connected to the second inlet, so that the flue gas and steam are in the heat exchanger 2 Heat exchange is carried out inside, the temperature of the steam decreases, and the temperature of the flue gas increases. The first outlet is connected with the inlet of the denitrification device, so that the heated flue gas flows into the denitrification device to prevent the denitrification catalyst from deactivating.

The mixer 4 is connected with the steam port so that the steam flowing out of the boiler 1 flows into the mixer 4. The mixer 4 is connected with the heat exchanger 2 so that the steam after heat exchange by the heat exchanger 2 flows into the mixer 4. The mixer 4 is used for The steam is mixed to reduce the temperature of the steam to a first preset value. Specifically, as shown in Figure 1, the inlet of the mixer 4 is connected to the second outlet and the steam port of the heat exchanger 2 respectively. The steam in the boiler 1 flows into the mixer 4, and the heat exchanger 2 exchanges heat and cooled steam. Flows into the mixer 4 so that the steam in the boiler 1 and the steam after heat exchange in the heat exchanger 2 are mixed, so that the temperature of the mixer 4 is reduced to the first preset value, and the first preset value is 290°C, preventing the The temperature of the steam flowing out of the mixer 4 is too high, causing the molten salt in the molten salt energy storage component 6 to melt, ensuring the normal operation of the molten salt energy storage component 6 and extending the service life of the molten salt energy storage component 6 .

The steam heat storage system 100 has a first state and a second state. In the first state, the molten salt energy storage component 6 is connected to the mixer 4 so that the steam mixed by the mixer 4 flows into the molten salt energy storage component 6 to make the molten salt energy storage component 6 . The salt energy storage component 6 stores energy. In the second state, the water pump 14 is connected to the molten salt energy storage component 6 so that the condensed water flows into the molten salt energy storage component 6 through the water pump 14 and interacts with the molten salt in the molten salt energy storage component 6 Heat is exchanged to release energy from the molten salt energy storage component 6 . Specifically, as shown in Figure 1, in the first state, the molten salt energy storage component 6 stores energy, the inlet of the molten salt energy storage component 6 is connected to the outlet of the mixer 4, and the mixed steam in the mixer 4 flows into the molten salt storage. In the energy component 6, the molten salt energy storage component 6 absorbs the heat in the steam to store energy and liquefies the steam into condensed water. In the second state, the molten salt energy storage component 6 releases energy. The inlet of the molten salt energy storage component 6 is connected to the water pump 14. The water pump 14 transports the condensate water into the molten salt energy storage component 6. The condensate water and the molten salt energy storage component The molten salt in 6 exchanges heat, causing the temperature of the condensed water to rise and vaporize into a gaseous state.

The steam heat storage system 100 in the embodiment of the present invention is provided with a heat exchanger 2 and a mixer 4, and uses part of the steam in the boiler 1 to heat the inlet flue gas of the denitrification device, ensuring the operational safety of the denitrification device at low load operation. Compared with technologies such as flue gas bypass, the flue temperature control is more precise and requires less maintenance. At the same time, because heating the flue gas consumes part of the steam heat, the amount of steam extracted during the heat storage peak shaving process is increased, which improves the unit's deep peak shaving capability. , in addition, a molten salt energy storage component 6 and a water pump 14 are provided to directly store the heat energy generated by the steam of the boiler 1 in the molten salt energy storage component 6. Compared with the electric heat storage peak-shaving method of the related technology, it goes through heat → electricity → heat twice. The energy conversion process reduces the intermediate process of conversion into electricity and improves energy conversion efficiency.

In some embodiments, the steam heat storage system 100 further includes a liquid storage tank 10. In the first state, the liquid storage tank 10 is connected to the molten salt energy storage assembly 6 so that the condensed water after heat exchange by the molten salt energy storage assembly 6 can flows into the liquid storage tank 10. Specifically, as shown in Figure 1, the inlet of the liquid storage tank 10 is connected with the outlet of the molten salt energy storage component 6. In the first state, the steam flowing out from the mixer 4 is liquefied into condensation through energy storage by the molten salt energy storage component 6. The water then flows into the liquid storage chamber, so that the liquid storage tank 10 stores condensation water.

In some embodiments, the steam heat storage system 100 further includes a temperature adjustment component, which is connected to the liquid storage tank 10 and used to deliver condensate water to the liquid storage tank 10 to adjust the temperature in the liquid storage tank 10 . Specifically, as shown in Figure 1, the temperature adjustment assembly includes a first water pump 12 and a condensate water heater 13, so that the condensate water formed by the boiler 1 unit is transported to the liquid storage tank 10 through the first water pump 12 or the condensate water heater 13. within, thereby adjusting the temperature of the condensed water in the liquid storage tank 10 to about 95°C, preventing the condensed water in the liquid storage tank 10 from vaporizing, improving the storage efficiency of the liquid storage tank 10, and extending the energy storage of the liquid storage tank 10 life.

In some embodiments, as the molten salt energy storage component 6 releases energy, the temperature of the molten salt in the molten salt energy storage component 6 gradually decreases, and the temperature of the steam coming out of the upper outlet of the molten salt energy storage component 6 no longer meets the requirement for heating. demand or auxiliary steam demand. Therefore, in some embodiments, in the second state, the liquid storage tank 10 is connected to the water pump 14 , so that the condensed water in the liquid storage tank 10 flows into the molten salt energy storage assembly 6 through the water pump 14 , thereby passing through the water pump 14 in the liquid storage tank 10 . The condensed water exchanges heat with the molten salt energy storage component 6, so that the molten salt energy storage component 6 continues to release energy. Since the temperature of the molten salt in the molten salt energy storage component 6 and the temperature of the condensed water in the water tank are significantly different, the improvement The energy release and heat exchange efficiency of the molten salt energy storage component 6 is determined.

In some embodiments, as the temperature of the molten salt in the molten salt energy storage component 6 rises, the condensed water flowing out from the outlet of the molten salt energy storage component 6 changes to steam. Therefore, in some embodiments, the steam heat storage system 100 further includes a steam header 8 , and the steam header 8 is connected to the molten salt energy storage component 6 so that the steam after being heat exchanged by the molten salt energy storage component 6 flows into the steam header. 8. Steam header 8 is used to replace the auxiliary steam or extraction steam of the unit. Specifically, as shown in Figure 1, the inlet of the steam header 8 is connected with the outlet of the energy storage component. The steam after heat exchange by the molten salt energy storage component 6 flows into the steam header 8, thereby replacing the auxiliary steam of the unit through the steam header 8. Or extract steam, thereby improving the efficiency of the steam heat storage system 100 .

In some embodiments, the steam heat storage system 100 further includes a heating pipe 20. In the second state, the heating pipe 20 is connected to the molten salt energy storage component 6 so that the heated steam can be released by the molten salt energy storage component 6. It flows into the heating pipe 20, which is used to provide heat to the client. Specifically, as shown in Figure 1, the inlet of the heating pipe 20 is connected to the outlet of the molten salt energy storage component 6. In the second state, the condensed water releases energy from the molten salt energy storage component 6 and is heated into steam and then flows into the heating pipe. 20, so that the heated steam released through the molten salt energy storage component 6 flows into the heating pipe 20, and the client is heated through the heating pipe 20.

In some embodiments, the temperature of the steam flowing out of the mixer 4 is a first temperature, the temperature of the molten salt in the molten salt energy storage component 6 is a second temperature, and the difference between the first temperature and the second temperature is less than the second temperature. At the preset value, the mixer 4 is connected to the steam header 8 so that the steam mixed by the mixer 4 flows into the steam header 8 , and/or the mixer 4 is connected to the heating pipe 20 so that the steam mixed by the mixer 4 flows into the steam header 8 . The final steam flows into the heating pipe 20. Specifically, as shown in Figure 1, when the temperature difference between the steam temperature at the outlet of the mixer 4 and the steam temperature at the outlet of the molten salt energy storage component 6 is less than the second preset value, the second preset value is 20°C, and the molten salt energy storage After the heat storage of component 6 is completed, the outlet of mixer 4 is connected to the inlet of steam header 8, so that the mixed steam flows into steam header 8, or the outlet of mixer 4 is connected to the inlet of heating pipe 20, so that the mixed steam is The resulting steam flows into the heating pipe 20, or the outlet of the mixer 4 is connected to the inlet of the heating pipe 20 and the steam header 8 respectively, so that the mixed steam flows into the heating pipe 20 and the steam header 8, Improves steam utilization and reduces energy waste.

In some embodiments, the steam heat storage system 100 further includes a deaerator 16 connected to the water pump 14 to remove oxygen from the condensed water flowing into the water pump 14. In the second state, the molten salt energy storage component 6 It is connected to the deaerator 16 so that the steam after energy release and heat exchange by the molten salt energy storage component 6 flows into the deaerator 16 . Specifically, as shown in Figure 1, the inlet of the deaerator 16 is connected to an external pipeline, and the outlet of the deaerator 16 is connected to the inlet of the water pump 14, so that the condensed water flows into the deaerator 16 through the external pipeline, and then passes through the deaerator. 16 After removing the oxygen in the condensate water, it flows into the molten salt energy storage component 6, thereby preventing the oxygen in the condensation water from reacting with the molten salt in the molten salt energy storage component 6, thereby increasing the service life of the molten salt energy storage component 6. In the second state, the outlet of the molten salt energy storage component 6 is connected to the inlet of the deaerator 16, so that the steam after energy release and gasification flows into the deaerator 16, reducing the steam extraction of the deaerator 16 and reducing coal consumption for power generation. .

In some embodiments, the molten salt energy storage component 6 includes multiple molten salt energy storage units, and the multiple molten salt energy storage units are connected in sequence so that steam and condensation water can be gradually heat exchanged within the molten salt energy storage component 6 . Specifically, the molten salt energy storage component 6 can be a plurality of molten salt energy storage units connected in series, so that steam and hot water can perform stepwise heat exchange with the molten salt in the multiple molten salt energy storage units.

It can be understood that the molten salt energy storage component 6 is an integrated heat storage and release device. When storing heat, steam enters from the upper inlet of the molten salt energy storage component 6 and comes out from the lower part of the molten salt energy storage component 6. When releasing heat, hot water Entering from the lower part of the molten salt energy storage component 6 and coming out from the molten salt energy storage component 6, the heat storage and heat release share the same set of heat exchangers 2, and only the flow direction of the working fluid is changed. The reheat steam extraction volume of boiler 1 shall not exceed 25% of the total reheat steam flow.

The steam heat storage system 100 according to the embodiment of the present invention will be described in detail below based on FIG. 1 .

The heat exchanger 2 is arranged in front of the inlet of the denitrification device in the tail flue of the boiler 1. The second inlet of the heat exchanger 2 is connected to the steam port of the boiler 1 through the first valve 3. The second outlet of the heat exchanger 2 is connected to the mixer 4. The inlet of the mixer 4 is connected, the other side of the mixer 4 is connected with the steam port of the boiler 1 through the second valve 5, and the outlet of the mixer 4 is connected with the upper inlet of the molten salt energy storage component 6. The lower outlet pipe of the molten salt energy storage component 6 is connected to the inlet of the steam header 8 through the third valve 7 and is connected to the upper inlet pipe of the liquid storage tank through the fourth valve 9 . The inlet of the liquid storage tank is also connected to the outlet of the first water pump 12 and the outlet of the condensate heater 1313 through the fourth valve 9 .

One inlet of the lower part of the molten salt energy storage component 6 is connected to the condensate water pipe (not shown in the figure) at the outlet of the deaerator 16 through the fifth valve 11 and the water pump 14, and the other is connected to the liquid storage tank through the water pump 14 and the sixth valve 15. The lower outlet is connected; the upper outlet of the molten salt energy storage component 6 is connected to three pipelines respectively, one is connected to the inlet condensate pipe of the deaerator 16, the other is connected to the unit heating pipe 20 through the seventh valve 18, and the other is connected to the unit heating pipe 20 through the seventh valve 18. It communicates with the steam header 8 through the eighth valve 19 .

The heat storage process is as follows: Boiler 1 operates at low load, and part of the reheated steam is extracted from boiler 1. The flue gas temperature is heated to above 290°C through the heat exchanger 2 arranged in front of the entrance of the denitrification device in the tail flue of boiler 1. From The steam from the heat exchanger 2 and part of the reheated steam extracted from the boiler 1 enter the steam mixer 4 from both sides of the mixer 4. The steam flow on both sides is adjusted by adjusting the first valve 3 and the second valve 5 to ensure mixing. The steam temperature at the outlet of the device 4 does not exceed the decomposition temperature of the molten salt in the molten salt energy storage component 6 . The mixed steam enters from the upper inlet of the molten salt energy storage component 6 and fully exchanges heat with the molten salt in the molten salt energy storage component 6. The temperature of the molten salt in the molten salt energy storage component 6 gradually increases, gradually completing the steam heat storage process. . Coming out of the lower outlet of the molten salt energy storage component 6, the steam after heat exchange with the molten salt passes through the first part of the fourth valve 9 and turns into saturated water from the upper part of the liquid storage tank into the liquid storage tank. In order to ensure that the water temperature in the liquid storage tank does not exceed 95°C, the fifth valve 11 can be used to adjust the amount of water entering the liquid storage tank through the first water pump 12 and the condensate water heater 1313. As the temperature of the molten salt in the molten salt energy storage component 6 rises, what comes out from the lower outlet of the molten salt energy storage component 6 will no longer be saturated water, but steam. The steam will be connected to the steam header 8 through the fourth valve 9 , can be used to replace the auxiliary steam or extraction steam of the unit. When the temperature difference between the outlet steam temperature of the mixer 4 and the outlet steam temperature of the lower part of the molten salt energy storage component 6 is within 20°C, the heat storage of the molten salt energy storage component 6 can be considered to be completed, and the steam at the outlet of the mixer 4 is directly connected through the ninth valve 17 The steam header 8 is connected to the heating pipeline 20 or through the eighth valve 19 and is no longer connected to the molten salt energy storage component 6 .

The heat release process is as follows: when the heat storage in the molten salt energy storage component 6 is full, the heat release mode can be entered. The condensed water from the outlet of the deaerator 16 enters the molten salt energy storage assembly 6 from the lower inlet of the molten salt energy storage assembly 6 through the sixth valve 15 through the water pump 14, and fully exchanges heat with the high-temperature molten salt in the molten salt energy storage assembly 6. , the condensed water is gradually heated, heated, and vaporized in the molten salt energy storage component 6, and finally turns into superheated steam and comes out from the upper outlet of the molten salt energy storage component 6. The steam after heat exchange with high-temperature molten salt is connected to the heating pipe 20 through the eighth valve 19 for heat supply, and is connected to the steam header 8 through the ninth valve 17 to replace the auxiliary steam or extraction steam of the unit and reduce the coal consumption of the unit for power generation. . As the heat release process proceeds, the temperature of the molten salt in the molten salt energy storage component 6 gradually decreases. When the temperature of the steam coming out of the upper outlet of the molten salt energy storage component 6 no longer meets the heating demand or auxiliary steam demand, close the deaerator. The sixth valve 15 between the outlet of 16 and the lower inlet of the molten salt energy storage component 6 opens the seventh valve 18, and sends the hot water in the liquid storage tank to the lower inlet of the molten salt energy storage component 6 through the water pump 14. After the hot water enters the molten salt energy storage component 6, it exchanges heat with the molten salt. After the water temperature gradually increases, it comes out from the upper outlet of the molten salt energy storage component 6 and is merged into the condensate water pipe at the inlet of the deaerator 16, which can reduce the number of low-pressure heaters. and deaerator 16 to reduce coal consumption for power generation. When the temperature of the hot water coming out of the upper outlet of the molten salt energy storage component 6 is lower than 130°C, it can be considered that the heat release process of the molten salt energy storage component 6 is over.

In order to further illustrate the working principle and performance advantages of the steam heat storage system 100 of the present invention, the following takes a 660MW coal power unit equipped with an 80MW.h steam heat storage peak-shaving device as an example to briefly describe its process flow and energy conversion of the energy storage device. efficiency. For a 660MW unit, the inlet smoke temperature of the denitrification device is 260°C at 25% rated load. 65t/h reheated steam is extracted into the steam-flue gas heat exchanger 2, and the inlet smoke temperature of the denitrification device is raised to above 290°C. After heating, The flue gas steam is mixed with part of the reheated steam and directly enters the molten salt energy storage device for heat storage. The remaining heat of the stored steam is partly converted into hot water and stored in a hot water tank, and partly converted into steam above 230°C. Entering the steam header 8, it replaces the four-extraction steam and is used to heat the steam in the steam-driven induced draft fan, steam-driven feed water pump 14, and deaerator 16, thereby solving the problem of insufficient four-extraction steam at low load. During the heat release process, hot water enters the molten salt energy storage device for heat exchange. When the temperature is higher than 230°C, the generated steam enters the steam header 8; when the temperature is lower than 230°C and higher than 130°C, deaeration is introduced The condensed water at the inlet of the deaerator 16 is reduced to reduce the steam extraction of the deaerator 16 and the low-pressure heater. In terms of energy conversion efficiency of the energy storage device, through calculation, the energy conversion efficiency of directly extracting reheated steam for heat storage and release is 50.37%, and the energy conversion efficiency of heating the flue gas and then storing and releasing heat is 72.97%. After the cascade utilization of hot steam heat, the energy conversion efficiency of the energy storage device is higher. In terms of peak shaving capacity, by heating the flue gas with 65t/h extraction reheat steam, the peak shaving capacity is increased by about 20MW compared with the peak shaving of simple extraction reheat steam, and the problem of low-load denitrification of boiler 1 is solved, and the peak shaving capacity of the unit is relatively high. Significantly improved before.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis", The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply the referred devices or components. Must have a specific orientation, be constructed and operate in a specific orientation and are therefore not to be construed as limitations of the invention.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In the present invention, unless otherwise expressly stipulated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; it can be mechanically connected, electrically connected, or communicable with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the internal connection between two elements or the interaction between two elements, Unless otherwise expressly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise expressly stated and limited, a first feature being "on" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. touch. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

As used herein, the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean specific features, structures, materials, or features described in connection with the embodiment or example. Features are included in at least one embodiment or example of the invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

Although the above embodiments have been shown and described, it can be understood that the above embodiments are illustrative and should not be construed as limitations of the present invention. Changes, modifications, substitutions and modifications of the above embodiments may be made by those of ordinary skill in the art. All are within the protection scope of the present invention.

Claims (10)

1. A steam heat storage system, characterized by comprising: A boiler having a flue and a steam outlet; A heat exchanger, which is connected to the flue and the steam port respectively, so that the flue gas and steam in the boiler flow into the heat exchanger respectively and exchange heat in the heat exchanger. To increase the temperature of the flue gas; Mixer, the mixer is connected to the steam port, so that the steam flowing out of the boiler flows into the mixer, and the mixer is connected to the heat exchanger, so that after heat exchange by the heat exchanger The steam flows into the mixer, and the mixer is used to mix the steam so that the temperature of the steam directly introduced into the mixer from the steam port is reduced to a first preset value; Molten salt energy storage component and water pump, the steam heat storage system has a first state and a second state, in the first state, the molten salt energy storage component is connected to the mixer so as to pass through the mixer The mixed steam flows into the molten salt energy storage component to store energy in the molten salt energy storage component. In the second state, the water pump is connected to the molten salt energy storage component so that condensed water can pass through the The water pump flows into the molten salt energy storage component and exchanges heat with the molten salt in the molten salt energy storage component to release energy from the molten salt energy storage component. 2. The steam heat storage system according to claim 1, further comprising a liquid storage tank, and in the first state, the liquid storage tank is connected to the molten salt energy storage component so as to pass through the The condensed water after heat exchange of the molten salt energy storage component flows into the liquid storage tank. 3. The steam heat storage system according to claim 2, further comprising a temperature adjustment component connected to the liquid storage tank for transporting condensed water to the liquid storage tank to adjust The temperature inside the liquid storage tank. 4. The steam heat storage system according to claim 2, wherein in the second state, the liquid storage tank is connected to the water pump, so that the condensed water in the liquid storage tank passes through the water pump. into the molten salt energy storage component. 5. The steam heat storage system according to claim 1, further comprising a steam header, the steam header being connected to the molten salt energy storage component so as to exchange heat through the molten salt energy storage component. The final steam flows into the steam header, which is used to replace the auxiliary steam or extraction steam of the unit. 6. The steam heat storage system according to claim 5, wherein the temperature of the steam flowing out of the mixer is a first temperature, and the temperature of the molten salt in the molten salt energy storage component is a second temperature. When the difference between the first temperature and the second temperature is less than a second preset value, the mixer is connected to the steam header so that the steam mixed by the mixer flows into the steam header. box. 7. The steam heat storage system according to claim 1, further comprising a heating pipe, and in the second state, the heating pipe is connected to the molten salt energy storage component so as to pass through the The heated steam released by the molten salt energy storage component flows into the heating pipe, and the heating pipe is used to heat the client. 8. The steam heat storage system according to claim 7, wherein the temperature of the steam flowing out of the mixer is a first temperature, and the temperature of the molten salt in the molten salt energy storage component is a second temperature. When the difference between the first temperature and the second temperature is less than a second preset value, the mixer is connected to the heating pipe so that the steam mixed by the mixer flows into the heating pipe. pipeline. 9. The steam heat storage system according to claim 1, further comprising a deaerator connected to the water pump to remove oxygen from the condensed water flowing into the water pump. In the second state, the molten salt energy storage component is connected to the deaerator, so that the steam after energy release and heat exchange by the molten salt energy storage component flows into the deaerator. 10. The steam heat storage system according to any one of claims 1 to 9, characterized in that the molten salt energy storage component includes a plurality of molten salt energy storage units, and the plurality of molten salt energy storage units are sequentially Communicated so that the steam and the condensed water can exchange heat step by step within the molten salt energy storage component.