阅读说明：本技术 一种煤电机组电热综合储能调峰系统与工作方法 (Electric heating comprehensive energy storage peak regulation system of coal electric unit and working method ) 是由 周科 张广才 徐党旗 晋中华 李明皓 鲁晓宇 白永岗 于 2021-09-26 设计创作，主要内容包括：本发明公开了一种煤电机组电热综合储能调峰系统与工作方法,通过将煤电机组的锅炉、汽轮机、发电机及其附属系统与熔盐储能系统相耦合,既能将煤电机组发出的电能和高温蒸汽储存在熔盐储能系统中,又能将熔盐储能系统中热能输出用于供热、供汽,或生成高温蒸汽重新送入汽轮机中进行发电,实现电能、热能的灵活存储和灵活释放,增加了煤电机组调节灵活性,可有效提升煤电机组消纳可再生能源发电的能力,助力我国实现碳达峰、碳中和。(The invention discloses an electric heating comprehensive energy storage peak regulation system and a working method of a coal-electric machine set, wherein a boiler, a steam turbine, a generator and auxiliary systems thereof of the coal-electric machine set are coupled with a molten salt energy storage system, so that electric energy and high-temperature steam generated by the coal-electric machine set can be stored in the molten salt energy storage system, the heat energy output in the molten salt energy storage system can be used for heat supply and steam supply, or the generated high-temperature steam is sent into the steam turbine again for power generation, the flexible storage and flexible release of the electric energy and the heat energy are realized, the adjustment flexibility of the coal-electric machine set is increased, the power generation capacity of the coal-electric machine set for absorbing renewable energy sources can be effectively improved, and China is helped to realize carbon peak reaching and carbon neutralization.)

1. An electric heating comprehensive energy storage and peak regulation system of a coal-electric machine set is characterized by comprising a boiler (1), a steam turbine (2), a generator (3), a molten salt tank (4), molten salt (5), a heat storage filler (6), a molten salt electric heating tank (7), a molten salt electric heater (8), a molten salt pump (9), a steam heat exchanger (10), a water supply heat exchanger (11), a deaerator (12), a water supply pump (13), a heat supply initial station (14), a steam heat exchanger inlet pipeline (15), a steam heat exchanger outlet pipeline (16), a water supply heat exchanger inlet pipeline (17), a water supply heat exchanger outlet pipeline (18) and a molten salt pipeline (19);

the molten salt (5), the heat storage filler (6), the steam heat exchanger (10) and the water supply heat exchanger (11) are uniformly distributed in the molten salt tank (4), the molten salt electric heater (8) is arranged in the molten salt electric heating tank (7), the molten salt electric heating tank (7) is connected with the molten salt tank (4) through a molten salt pipeline (19) and a molten salt pump (9), and the molten salt (5) is circulated between the molten salt electric heating tank (7) and the molten salt tank (4) through the molten salt pump (9);

one path of high-temperature steam from the boiler (1) is connected with a steam turbine (2) for steam power generation, the other path of high-temperature steam is connected with an inlet pipeline (15) of a steam heat exchanger in a molten salt tank (4), and the steam heat exchanger (10) is used for storing the heat of the high-temperature steam in a molten salt (5) in the molten salt tank (4); the generator (3) is connected with the steam turbine (2); the fused salt electric heater (8) is connected with the outlet of the generator (3), and the electric energy generated by the generator (3) is used for heating the fused salt (5) through the fused salt electric heater (8) and is stored in the fused salt (5) in the fused salt tank (4); an outlet pipeline (16) of the steam heat exchanger is connected with a deaerator (12), and residual heat of steam after heat exchange with the molten salt (5) is recycled to the deaerator (12); the inlet pipeline (17) of the water supply heat exchanger is connected with the water supply pump (13), one path of the outlet pipeline (18) of the water supply heat exchanger is connected with the steam inlet pipeline of the steam turbine (2) and used for converting heat stored in the fused salt (5) into high-temperature steam and returning the high-temperature steam to the steam turbine (2) for power generation, and the other path of the outlet pipeline enters the heat supply initial station (14) through the steam pipeline and is used for taking away the heat stored in the fused salt (5) and supplying heat for heating or supplying steam for industry.

2. The electric heating comprehensive energy storage and peak regulation system of the coal electric unit as claimed in claim 1, characterized in that the steam heat exchanger (10) and the feedwater heat exchanger (11) are arranged in a staggered manner in the molten salt tank (4).

3. The electric heating comprehensive energy storage and peak shaving system of the coal electric unit as claimed in claim 2, characterized in that the inlet of the steam heat exchanger (10) is arranged at the top of the molten salt tank (4), and the outlet is arranged at the bottom of the molten salt tank (4).

4. The electric heating comprehensive energy storage and peak regulation system of the coal electric unit as claimed in claim 2, characterized in that the inlet of the feed water heat exchanger (11) is at the bottom of the molten salt tank (4) and the outlet is at the top of the molten salt tank (4).

5. The electric heating comprehensive energy storage and peak regulation system of the coal-electric machine set according to claim 1, characterized in that the heat storage filler (6) in the molten salt tank (4) is fixed in the molten salt tank (4) and does not flow along with the flow of the molten salt (5) in the molten salt tank (4).

6. The electric heating comprehensive energy storage and peak regulation system of the coal-electric machine set as claimed in claim 1, characterized in that the molten salt tank (4) is a series combination of a plurality of independent heat exchange tank bodies, and steam and feed water are subjected to gradual heat exchange with the molten salt (5) in the plurality of heat exchange tank bodies.

7. An operating method of an electric heating comprehensive energy storage peak regulation system of a coal electric unit is characterized in that the method is based on the electric heating comprehensive energy storage peak regulation system of the coal electric unit as claimed in any one of claims 1 to 6, and comprises the following steps:

when the unit needs peak shaving, electric energy storage or heat energy peak shaving is adopted, or electric energy and heat energy peak shaving are simultaneously stored; when the electric energy needs to be stored, starting a molten salt electric heater (8) in a molten salt electric heating tank (7), converting the electric energy generated by a coal-electric machine set generator (3) into heat energy, starting a molten salt pump (9), heating the molten salt (5) to more than 500 ℃ step by step through circulation of the molten salt (5), and finishing the electric energy storage process; when heat energy needs to be stored, a steam pipeline valve connected with the boiler (1) and the molten salt tank (4) is opened, high-temperature steam enters a steam heat exchanger (10) in the molten salt tank (5) from a steam heat exchanger inlet pipeline (15), a molten salt pump (9) is started at the same time, molten salt is heated to more than 500 ℃ gradually through circulation of the molten salt (5), the steam after heat release is sent into a deaerator (12), and the process of storing the heat energy is finished; when electric energy and heat energy need to be stored simultaneously, a molten salt electric heater (8) in a molten salt electric heating tank (7) is started simultaneously, a steam pipeline valve connected with a boiler (3) and a molten salt tank (4) is opened, a molten salt pump (9) is started simultaneously, molten salt is heated to more than 500 ℃ gradually under the combined action of electric heating and high-temperature steam, and the process of storing the electric energy and the heat energy is finished;

when the machine set does not need peak regulation, the heat in the molten salt tank (4) is released and converted into heat energy or electric energy; when heat supply or industrial steam supply needs exist, a water supply pump (13) is started, water is introduced into an inlet pipeline (17) of a water supply heat exchanger and enters a molten salt tank (4) for heat exchange, and generated high-temperature steam enters a heat supply initial station (14) after coming out of an outlet pipeline (18) of the water supply heat exchanger and is used for resident heating or industrial steam supply; when the unit has no heat supply or industrial steam supply demand, a water supply pump (13) is started, water is introduced into an inlet pipeline (17) of a water supply heat exchanger and enters a molten salt tank (4) for heat exchange, and generated high-temperature steam is sent into a steam turbine (2) for power generation through a steam pipeline after coming out of an outlet pipeline (18) of the water supply heat exchanger; when the temperature and the pressure of high-temperature steam coming out of an outlet pipeline (18) of the water supply heat exchanger are not matched with the main steam or reheat steam inlet parameters of the steam turbine (2), the high-temperature steam generated by heat exchange in the molten salt tank (4) can smoothly enter the main steam or reheat steam pipeline of the steam turbine (2) to push the steam turbine (2) to do work and generate power by adjusting the power of the molten salt electric heater (8) and the pressure of the water supply pump (13) to match with the main steam or reheat steam inlet parameters.

8. The operating method of the comprehensive electric heating energy storage and peak regulation system of the coal-electric machine set according to claim 7, characterized in that when electric energy and heat energy are stored simultaneously, a steam pipeline valve connected with a boiler and a molten salt tank is started, a molten salt pump is started simultaneously, molten salt is heated to a temperature within a range of 400-450 ℃ by steam, a molten salt electric heater in a molten salt electric heating tank is started, the molten salt is heated to a temperature above 540 ℃ step by step through electric heating, the capacity of steam heat storage and the temperature rise capability of the electric heat storage are fully utilized, and meanwhile, the steam energy generated when the energy is released is ensured to be equivalent to the rated steam temperature of the machine set.

9. The working method of the electric heating comprehensive energy storage and peak shaving system of the coal-electric unit as claimed in claim 7, wherein when storing heat energy, all of part of main steam and all of reheated steam generated by the boiler (1) are sent to the steam heat exchanger (10) in the molten salt tank (4), the rest part of main steam does not enter a high-pressure cylinder of the steam turbine (2), and enters a reheater of the boiler (1) after temperature and pressure reduction, so that the steam turbine (2) does not work, and the generator (3) outputs zero power.

Technical Field

The invention belongs to the technical field of energy storage of coal-electric units, and particularly relates to an electric heating comprehensive energy storage peak shaving system and a working method of a coal-electric unit.

Background

With the rapid development of wind power and photovoltaic power generation, the demand of a power grid on a flexible power supply is continuously improved, and the positioning of coal power in a power grid system is gradually changed from an electric quantity type power supply to an electric quantity and electric power regulation type power supply. At present, a unit with better coal quality and equipment conditions is transformed flexibly, the load regulation range of the unit can be widened from 50% -100% of rated load to 30% -100% of rated load, and the increased 20% of rated load regulation range can absorb new energy power with the same capacity. However, part of the units are influenced by coal quality and equipment conditions, the minimum technical output reduction of the units is limited, and the load regulation capacity is poor. In order to stimulate the coal-electric machine set to actively participate in deep peak regulation, the operating rules of the electric power auxiliary service market are issued successively in northeast, Shanxi, Gansu, Fujian and the like, economic subsidies are applied to the machine set participating in deep peak regulation and frequency regulation, and on the contrary, the machine set incapable of participating in deep peak regulation is examined. Especially for the unit participating in heating or industrial steam supply, the pressure of deep peak regulation is higher, so that the unit not only needs to ensure heating or industrial steam supply, but also needs to participate in peak regulation and frequency modulation of a power grid, and the peak regulation capability of the unit is urgently needed to be improved.

Aiming at the coal-electricity unit with insufficient peak regulation capacity and heavy peak regulation task, an auxiliary unit provided with an energy storage or heat storage device is an option to participate in deep peak regulation. The main energy storage or heat storage technologies include: electrode boilers, hot water tank heat storage, fused salt heat storage, solid heat storage, storage battery energy storage, flywheel energy storage, compressed air energy storage and the like. The electrode boiler, the hot water tank heat storage, the molten salt heat storage and the solid heat storage are mainly used for the auxiliary deep peak shaving of a coal-fired unit in the northern area during the heating period or in the unit with industrial steam supply requirement, electric energy is directly converted into heat energy or stored for heating or industrial steam supply, but once no heat user exists, the energy storage or heat storage technology has no application scene. The storage battery is mainly used for the coal-electric unit in the area with larger power grid frequency modulation demand, and is influenced by higher cost, fast battery attenuation, difficult secondary pollution and the like, and the storage battery is used for large-scale peak modulation of the coal-electric unit and has a longer path to walk. Flywheel energy storage and compressed air energy storage are still in the demonstration phase at present.

The invention patent with the application number of 202011317852.5 discloses a new energy coupling thermal power generating unit power generation energy storage peak regulation combined system and an operation method.

The invention patent with the application number of 202011166654.3 discloses a thermal power unit peak regulation and frequency modulation system and method based on liquid compressed air energy storage, wherein the liquid compressed air energy storage system is in multiple coupling with a thermal power unit steam-water thermodynamic cycle, so that the storage and release of partial energy of the thermal power unit steam-water thermodynamic cycle are realized, and the thermal power unit peak regulation and frequency modulation capability participating in a power grid is improved.

Under the big background of new forms of energy electric power consumption, in order to solve the energy storage or the heat-retaining problem of the non-heat supply period of coal-electric set in northern area to and the energy storage problem of the unit that does not have industry steam supply in southern area, a set of device that can get up electric energy or heat energy storage, can release electric energy or heat energy at any time need be studied urgently, improve energy storage device's conversion efficiency as far as possible simultaneously, present relevant research is less.

Disclosure of Invention

The invention aims to provide an electric heating comprehensive energy storage peak regulation system and a working method of a coal-electric machine set, aiming at the problem that the traditional energy storage and heat storage measures such as electrode boilers, hot water tank heat storage, solid heat storage and the like cannot be suitable for deep peak regulation operation under pure condensation working conditions of a heat supply unit or an industrial steam supply unit.

In order to achieve the purpose, the invention is realized by adopting the following technical scheme:

an electric heating comprehensive energy storage peak regulation system of a coal-electric machine set comprises a boiler, a steam turbine, a generator, a molten salt tank, molten salt, heat storage filler, a molten salt electric heating tank, a molten salt electric heater, a molten salt pump, a steam heat exchanger, a feed water heat exchanger, a deaerator, a feed water pump, a heat supply initial station, a steam heat exchanger inlet pipeline, a steam heat exchanger outlet pipeline, a feed water heat exchanger inlet pipeline, a feed water heat exchanger outlet pipeline and a molten salt pipeline;

the molten salt, the heat storage filler, the steam heat exchanger and the water supply heat exchanger are uniformly distributed in the molten salt tank, the molten salt electric heater is arranged in the molten salt electric heating tank, the molten salt electric heating tank is connected with the molten salt tank through a molten salt pipeline and a molten salt pump, and the molten salt is circulated between the molten salt electric heating tank and the molten salt tank through the molten salt pump;

one path of high-temperature steam from the boiler is connected with a steam turbine for steam power generation, and the other path of high-temperature steam is connected with an inlet pipeline of a steam heat exchanger in a molten salt tank, and the steam heat exchanger is used for storing heat of the high-temperature steam in molten salt in the molten salt tank; the generator is connected with the steam turbine; the fused salt electric heater is connected with the outlet of the generator, and the electric energy generated by the generator is used for heating fused salt through the fused salt electric heater and storing the fused salt in the fused salt tank; an outlet pipeline of the steam heat exchanger is connected with a deaerator, and residual heat of steam after heat exchange with molten salt is recycled to the deaerator; the inlet pipeline of the water supply heat exchanger is connected with the water supply pump, the outlet pipeline of the water supply heat exchanger is connected with the steam inlet pipeline of the steam turbine all the way, the heat stored in the fused salt is converted into high-temperature steam and sent back to the steam turbine for power generation, and the high-temperature steam enters the heat supply initial station through the steam pipeline all the way, and the heat stored in the fused salt is taken away for heating or industrial steam supply.

The invention is further improved in that the steam heat exchanger and the feed water heat exchanger are arranged in a staggered mode in the molten salt tank.

The invention is further improved in that the inlet of the steam heat exchanger is arranged at the top of the molten salt tank, and the outlet of the steam heat exchanger is arranged at the bottom of the molten salt tank.

The invention is further improved in that the inlet of the feed water heat exchanger is arranged at the bottom of the molten salt tank, and the outlet of the feed water heat exchanger is arranged at the top of the molten salt tank.

The invention is further improved in that the heat storage filler in the molten salt tank is fixed in the molten salt tank and does not flow along with the flow of the molten salt in the molten salt tank.

The invention has the further improvement that the molten salt tank is a series combination of a plurality of independent heat exchange tank bodies, and steam and feed water perform gradual heat exchange with the molten salt in the plurality of heat exchange tank bodies.

A working method of an electric heating comprehensive energy storage peak regulation system of a coal electric unit is based on the electric heating comprehensive energy storage peak regulation system of the coal electric unit and comprises the following steps:

when the unit needs peak shaving, electric energy storage or heat energy peak shaving is adopted, or electric energy and heat energy peak shaving are simultaneously stored; when the electric energy needs to be stored, starting a molten salt electric heater in the molten salt electric heating tank, converting the electric energy generated by the coal electric machine set generator into heat energy, starting a molten salt pump, gradually heating the molten salt to over 500 ℃ through molten salt circulation, and finishing the electric energy storage process; when heat energy needs to be stored, a steam pipeline valve connected with a boiler and a molten salt tank is opened, high-temperature steam enters a steam heat exchanger in the molten salt tank from an inlet pipeline of the steam heat exchanger, a molten salt pump is started at the same time, molten salt is heated to more than 500 ℃ gradually through molten salt circulation, the steam after heat release is sent into a deaerator, and the process of storing heat energy is finished; when electric energy and heat energy need to be stored simultaneously, a molten salt electric heater in a molten salt electric heating tank is started simultaneously, a steam pipeline valve connected with a boiler and a molten salt tank is opened, a molten salt pump is started simultaneously, molten salt is heated to more than 500 ℃ gradually under the combined action of electric heating and high-temperature steam, and the process of storing the electric energy and the heat energy is finished;

when the machine set does not need peak regulation, the heat in the molten salt tank is released and converted into heat energy or electric energy; when heat supply or industrial steam supply needs exist, a water supply pump is started, water supply is introduced into an inlet pipeline of a water supply heat exchanger and enters a molten salt tank for heat exchange, and generated high-temperature steam enters a heat supply initial station after coming out of an outlet pipeline of the water supply heat exchanger and is used for resident heating or industrial steam supply; when the unit has no heat supply or industrial steam supply demand, starting a water supply pump, introducing water supply into an inlet pipeline of a water supply heat exchanger, entering a molten salt tank for heat exchange, and sending generated high-temperature steam into a steam turbine for power generation through a steam pipeline after the generated high-temperature steam comes out from an outlet pipeline of the water supply heat exchanger; when the temperature and the pressure of high-temperature steam coming out of the outlet pipeline of the water supply heat exchanger are not matched with the parameters of main steam or reheat steam inlet of the turbine, the power of the molten salt electric heater and the pressure of the water supply pump are adjusted to be matched with the molten salt electric heater, so that the high-temperature steam generated by heat exchange in the molten salt tank can smoothly enter the main steam or reheat steam pipeline of the turbine to push the turbine to do work and generate power.

The further improvement of the invention is that when the electric energy and the heat energy are stored simultaneously, a steam pipeline valve connected with a boiler and a molten salt tank is firstly opened, a molten salt pump is simultaneously started, molten salt is heated to the range of 400-450 ℃ by steam, then a molten salt electric heater in a molten salt electric heating tank is started, the molten salt is heated to more than 540 ℃ step by step through electric heating, the capacity of steam heat storage and the temperature rise capability of the electric heat storage are fully utilized, the steam energy generated when the energy is released is ensured to be equivalent to the rated steam temperature of a unit, and the energy conversion efficiency is improved.

The invention has the further improvement that when the heat energy is stored, part of main steam and all reheated steam generated by the boiler are all sent into the steam heat exchanger in the molten salt tank, the rest part of main steam does not enter a high-pressure cylinder of the steam turbine, and enters a reheater of the boiler after temperature and pressure reduction, so that the zero-power output of the generator without work of the steam turbine can be realized.

Compared with the prior art, the invention has at least the following beneficial technical effects:

1) when storing energy, compared with the traditional electrode boiler, hot water tank, solid heat storage and other technologies which only can convert electric energy into heat energy for storage, the invention is provided with the molten salt electric heater and the steam heat exchanger at the same time, which not only can convert electric energy into heat energy for storage, but also can directly store heat energy through the steam heat exchanger, the energy storage mode is flexible, and the energy conversion efficiency is higher.

2) When releasing energy, the prior art basically uses the stored heat for resident heat supply, industrial steam supply and the like, or enters a low-grade regenerative system to exhaust steam of a steam turbine.

3) Compared with the traditional cold-hot tank molten salt energy storage technology, the invention adopts a single-tank molten salt technology and has the characteristics of small floor area, low investment and the like.

Drawings

Fig. 1 shows a schematic diagram of an electric heating integrated energy storage peak shaving system of a coal electric machine set.

Description of reference numerals:

1-boiler, 2-steam turbine, 3-generator, 4-molten salt tank, 5-molten salt, 6-heat storage filler, 7-molten salt electric heating tank, 8-molten salt electric heater, 9-molten salt pump, 10-steam heat exchanger, 11-water supply heat exchanger, 12-deaerator, 13-water supply pump, 14-heat supply initial station, 15-steam heat exchanger inlet pipeline, 16-steam heat exchanger outlet pipeline, 17-water supply heat exchanger inlet pipeline, 18-water supply heat exchanger outlet pipeline and 19-molten salt pipeline.

Fig. 2 shows a molten salt energy storage system formed by connecting a plurality of molten salt tanks in series, and the molten salt energy storage system is illustrated by taking three molten salt tanks in series as an example.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1, the electric heating comprehensive energy storage peak shaving system of the coal-electric machine set provided by the invention comprises a boiler 1, a steam turbine 2, a generator 3, a molten salt tank 4, molten salt 5, a heat storage filler 6, a molten salt electric heating tank 7, a molten salt electric heater 8, a molten salt pump 9, a steam heat exchanger 10, a water supply heat exchanger 11, a deaerator 12, a water supply pump 13, a heat supply initial station 14, a steam heat exchanger inlet pipeline 15, a steam heat exchanger outlet pipeline 16, a water supply heat exchanger inlet pipeline 17, a water supply heat exchanger outlet pipeline 18 and a molten salt pipeline 19.

The molten salt energy storage system comprises a molten salt tank 4, molten salt 5, a heat storage filler 6, a molten salt electric heating tank 7, a molten salt electric heater 8, a molten salt pump 9, a steam heat exchanger 10, a water supply heat exchanger 11, a steam heat exchanger inlet pipeline 15, a steam heat exchanger outlet pipeline 16, a water supply heat exchanger inlet pipeline 17, a water supply heat exchanger outlet pipeline 18 and a molten salt pipeline 19. Fused salt 5, heat accumulation filler 6, steam heat exchanger 10 and feedwater heat exchanger 11 equipartition are arranged in fused salt jar 4, and fused salt electric heater 8 arranges in fused salt electric heating groove 7, and fused salt electric heating groove 7 is connected with fused salt jar 4 through fused salt pipeline 19 through fused salt pump 9, realizes the circulation of fused salt 5 between fused salt electric heating groove 7 and fused salt jar 4 through fused salt pump 9.

One path of high-temperature steam from the boiler 1 is connected with a steam turbine 2 for steam power generation, the other path of high-temperature steam is connected with an inlet pipeline 15 of a steam heat exchanger in a molten salt tank 4, and the steam heat exchanger 10 is used for storing the heat of the high-temperature steam in a molten salt 5 in the molten salt tank 4; the generator 3 is connected with the steam turbine 2; the fused salt electric heater 8 is connected with the outlet of the generator 3, and the electric energy generated by the generator 3 is used for heating the fused salt 5 through the fused salt electric heater 8 and is stored in the fused salt 5 in the fused salt tank 4; an outlet pipeline 16 of the steam heat exchanger is connected with the deaerator 12, and residual heat of steam after heat exchange with the molten salt 5 is recycled to the deaerator 12; the inlet pipeline 17 of the water supply heat exchanger is connected with the water supply pump 13, the outlet pipeline 18 of the water supply heat exchanger is connected with the steam inlet pipeline of the steam turbine 2 in one way, the heat stored in the fused salt 5 is converted into high-temperature steam and sent back to the steam turbine 2 for power generation, and the heat in one way enters the heat supply initial station 14 through the steam pipeline and is used for taking away the heat stored in the fused salt 5 for heating or industrial steam supply.

Preferably, the steam heat exchanger 10 and the water heat exchanger 11 are arranged in a staggered manner in the molten salt tank 4, the inlet of the steam heat exchanger 10 is arranged at the top of the molten salt tank 4, the outlet is arranged at the bottom of the molten salt tank 4, the inlet of the water heat exchanger 11 is arranged at the bottom of the molten salt tank 4, and the outlet is arranged at the top of the molten salt tank 4.

Preferably, the heat storage filler 6 in the molten salt tank 4 is fixed in the molten salt tank 4 and does not flow with the flow of the molten salt 5 in the molten salt tank 4.

Preferably, the molten salt tank 4 can be a series combination of a plurality of independent heat exchange tank bodies, and steam and feed water perform heat exchange with the molten salt 5 step by step in the plurality of heat exchange tank bodies. As shown in fig. 2, three molten salt tanks are vertically overlapped, and the three molten salt tanks, a molten salt pump and a molten salt electric heater are connected through a molten salt pipeline, so that the circulation of molten salt in the whole system can be realized; the steam pipeline and the water supply pipeline are also arranged in series and exchange heat with the molten salt in the molten salt tank step by step.

The invention provides a working method of an electric heating comprehensive energy storage peak shaving system of a coal-electric machine set, when the machine set needs peak shaving, the peak shaving is carried out by adopting electric energy storage or heat energy storage, or simultaneously electric energy and heat energy storage; when the electric energy needs to be stored, the molten salt electric heater 8 in the molten salt electric heating tank 7 is started, the electric energy generated by the coal electric machine set generator 3 is converted into heat energy, the molten salt pump 9 is started simultaneously, the molten salt 5 is gradually heated to more than 500 ℃ through the circulation of the molten salt 5, and the electric energy storage process is finished; when heat energy needs to be stored, a steam pipeline valve of the boiler 1 connected with the molten salt tank 4 is opened, high-temperature steam enters a steam heat exchanger 10 in the molten salt tank 5 from an inlet pipeline 15 of the steam heat exchanger, a molten salt pump 9 is started at the same time, molten salt is heated to more than 500 ℃ gradually through circulation of the molten salt 5, the steam after heat release is sent into a deaerator 12, and the process of storing heat energy is finished; when electric energy and heat energy need to be stored simultaneously, the molten salt electric heater 8 in the molten salt electric heating tank 7 is started simultaneously, a steam pipeline valve of the boiler 3 connected with the molten salt tank 4 is opened, the molten salt pump 9 is started simultaneously, molten salt is heated to more than 500 ℃ gradually under the combined action of electric heating and high-temperature steam, and the process of storing the electric energy and the heat energy is finished.

When the unit does not need peak regulation, the heat in the molten salt tank 4 is released in time and converted into heat energy or electric energy. When heat supply or industrial steam supply needs exist, a water supply pump 13 is started, water supply is introduced into an inlet pipeline 17 of a water supply heat exchanger and enters a molten salt tank 4 for heat exchange, and generated high-temperature steam enters a heat supply initial station 14 after coming out of an outlet pipeline 18 of the water supply heat exchanger and is used for resident heating or industrial steam supply; when the unit has no heat supply or industrial steam supply demand, a water supply pump 13 is started, water supply is introduced into a water supply heat exchanger inlet pipeline 17 and enters the molten salt tank 4 for heat exchange, and generated high-temperature steam is sent into the steam turbine 2 for power generation through a steam pipeline after coming out of a water supply heat exchanger outlet pipeline 18; when the temperature and the pressure of the high-temperature steam coming out of the outlet pipeline 18 of the water supply heat exchanger are not matched with the parameters of the main steam or the reheat steam inlet of the steam turbine 2, the power of the molten salt electric heater 8 and the pressure of the water supply pump 13 can be adjusted to be matched with the high-temperature steam, so that the high-temperature steam generated by heat exchange in the molten salt tank 4 can smoothly enter the main steam or the reheat steam pipeline of the steam turbine 2 to push the steam turbine 2 to do work and generate electricity.

Preferably, when electric energy and heat energy are stored simultaneously, a steam pipeline valve connected with the boiler 1 and the molten salt tank 4 is started, the molten salt pump 9 is started simultaneously, molten salt 5 is heated to a temperature within a range of 400-450 ℃ by steam, then the molten salt electric heater 8 in the molten salt electric heating tank 7 is started, the molten salt 5 is heated to a temperature above 540 ℃ step by step through electric heating, the capacity of steam heat storage and the temperature rise capability of electric heat storage are fully utilized, the steam energy generated when the energy is released is ensured to be equivalent to the rated steam temperature of a unit, and the energy conversion efficiency is improved.

When storing heat energy, part of main steam and all reheated steam generated by the boiler 1 are all sent to the steam heat exchanger 10 in the molten salt tank 4, the rest part of main steam does not enter the high-pressure cylinder of the steam turbine 2, and enters the reheater of the boiler 1 after temperature and pressure reduction, so that the steam turbine 2 does not work, and the generator 3 outputs zero power.

In order to further explain the working principle and performance advantages of the electric-heating integrated energy storage peak regulation system, a 300MW coal-electric machine set is taken as an example, and the electric-heating configuration and energy conversion efficiency are briefly described. A300 MW unit is respectively provided with 10MW x 4h electric heat storage and 30t/h high-reheat steam x 4h steam heat storage, the corresponding equivalent electric power of the operation is 17.4MW, the equivalent consumed electric quantity of the heat storage 4h is 69.6MW.h, the heat value of the electric heating heat storage is 144GJ, the average temperature rise of the steam heat storage fused salt is 160 ℃, the steam heat storage quantity is 361GJ, the total heat storage quantity is 505GJ, the reheat steam-feedwater enthalpy drop is 2.872MJ/kg, when the release energy is calculated, 175.9t of 540 ℃ reheat steam can be generated through fused salt heat exchange, 41.89MW.h can be generated, the energy conversion efficiency of the whole electric heating comprehensive energy storage process is 60.2% except 69.6MW.h equivalent consumed electric quantity, when the peak-valley-to-valley-peak-to-valley electric power cost ratio (peak-to-valley-peak-to-peak-valley electricity-to-price ratio is more than 2.3 in China, therefore, the electric heating comprehensive energy storage peak regulation system has better performance advantage and market prospect.

While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.