阅读说明：本技术 一种火力发电机组热水储能系统及方法 (Hot water energy storage system and method for thermal generator set ) 是由 潘利生 董跃华 魏小林 李森 刘冲 郭东奇 于 2021-01-20 设计创作，主要内容包括：本发明公开了一种火力发电机组热水储能系统,包括与火力发电机组的冷凝器出口连接的冷水储存单元、接收来自火力发电机组中的蒸汽以及冷水储存单元的冷水并加以混合的气液混合装置、与气液混合装置的出水口相连用于储存近饱和热水的热水储存单元；还公开了该火力发电机组热水储能系统的储能方法,在电网低负荷要求时,抽取火力发电机组中未完全膨胀的蒸汽与冷水储存单元的冷水混合为近饱和热水并储存在热水储存单元内；在电网高负荷要求时,抽取热水储存单元中的热水与火力发电机组中的锅炉用水混合并供向锅炉；该储能技术直接储存和释放热能,不存在多种形式能量的多次转化过程,综合储能效率较高,比热容较大、安全性好、价格低廉。(The invention discloses a hot water energy storage system of a thermal generator set, which comprises a cold water storage unit connected with an outlet of a condenser of the thermal generator set, a gas-liquid mixing device for receiving and mixing steam from the thermal generator set and cold water of the cold water storage unit, and a hot water storage unit connected with a water outlet of the gas-liquid mixing device and used for storing near-saturated hot water; when the power grid is in low load requirement, steam which is not fully expanded in the thermal generator set is extracted and mixed with cold water in a cold water storage unit to form near saturated hot water, and the near saturated hot water is stored in the hot water storage unit; when the high load of the power grid is required, hot water in the hot water storage unit is extracted to be mixed with boiler water in the thermal generator set and supplied to the boiler; the energy storage technology directly stores and releases heat energy, does not have multiple conversion processes of various forms of energy, and has the advantages of higher comprehensive energy storage efficiency, larger specific heat capacity, good safety and low price.)

1. The utility model provides a thermal generator set hot water energy storage system which characterized in that includes:

a cold water storage unit (30), wherein a water inlet of the cold water storage unit (30) is connected with a condenser outlet of the thermal generator set (10);

the gas-liquid mixing device (20) receives steam from the thermal generator set (10) and cold water from the cold water storage unit (30) and mixes the steam and the cold water to form near-saturated hot water with certain pressure;

the hot water storage unit (40) is connected with a water outlet of the gas-liquid mixing device (20) and used for storing near-saturated hot water and mixing the stored hot water with boiler feed water of the thermal generator set (10) when the power load of a power grid is high;

the cold water storage unit (30) comprises a cold water pipeline (31), the hot water storage unit (40) comprises a hot water pipeline (41), the cold water pipeline (31) and the hot water pipeline (41) are jointly connected with a plurality of dual-purpose storage tanks (51), the dual-purpose storage tanks (51) are used for alternately storing cold water and hot water, the cold water pipeline (31) is at least connected with a cold water storage tank (32) only storing cold water, and the hot water pipeline (41) is at least connected with a hot water storage tank (42) only storing hot water.

2. The thermal generator set hot water energy storage system according to claim 1, wherein the thermal generator set (10) comprises a generator (13), a boiler (11), a steam turbine (12), a condenser (14) and a heat regenerator (17) which are sequentially connected and form a closed loop, a deaerator (16) is arranged between the condenser (14) and the heat regenerator (17), the deaerator (16) is connected with a water supply pipe, exhaust steam in the steam turbine (12) is condensed into water through the condenser (14), condensed water is conveyed into the deaerator (16) through a first water pump (151) to be deaerated and then conveyed into the heat regenerator (17) through a second water pump (152), an outlet of the heat regenerator (17) is connected with a blending chamber (18), a middle air suction port of the steam turbine (12) is formed, and the heat regenerator (17) receives incompletely expanded steam extracted from the air suction port and incompletely expanded steam in the deaerator (16) And cold water is conveyed to the mixing chamber (18) to be mixed and then conveyed to the boiler (11) through the third water pump (153) to be heated, and the heated steam or supercritical water enters the steam turbine (12) to be expanded and work and drive the generator (13) to generate power.

3. A thermal generator set hot water energy storage system according to claim 2, characterized in that the middle part of the steam turbine (12) and the boiler (11) are connected by a loop pipe to form a closed path, and the loop pipe comprises a pipe for sending incompletely expanded steam extracted from the middle part of the steam turbine (12) to the boiler (11) for reheating and a delivery pipe for sending reheated steam to the steam turbine (12) for expansion and work.

4. A thermal generator set hot water energy storage system according to claim 3, wherein the water inlet end of the cold water pipeline (31) is connected with the water outlet of the condenser (14) through a pipeline, a fourth water pump (154) and a valve a (191) are arranged on the section of connecting pipeline, the water outlet end of the cold water pipeline (31) is connected with the water inlet of the gas-liquid mixing device (20) through a pipeline, and a fifth water pump (155) and a valve B (192) are arranged on the section of pipeline;

the water inlet end of the hot water pipeline (41) is connected with the water outlet of the gas-liquid mixing device (20) through a pipeline, the water outlet end of the hot water pipeline (41) is connected with the inlet of the mixing chamber (18) through a pipeline, and a sixth water pump (156) and a valve C (193) are arranged on the pipeline.

5. A thermal generator set hot water energy storage system according to claim 3, characterized in that the gas inlet of the gas-liquid mixing device (20) is connected with the delivery pipe for receiving the steam reheated by the boiler (11), a valve D (194) is arranged on the section of the delivery pipe, and a valve E (195) is arranged on the section of the delivery pipe close to the turbine.

6. A thermal generator set hot water energy storage system according to claim 4, characterized in that each cold water storage tank (32), hot water storage tank (42) and dual-purpose storage tank (51) is provided with an independent valve F (196) for controlling water inlet and outlet.

7. An energy storage method of the thermal generator set hot water energy storage system according to any one of claims 1-6, characterized by comprising the following steps:

step 100, when the power grid is in a low-load requirement, extracting steam which is not fully expanded in a thermal generator set, mixing the steam with cold water in a cold water storage unit to form near-saturated hot water, and storing the near-saturated hot water in a hot water storage unit;

and 200, when the high load of the power grid is required, extracting hot water in the hot water storage unit, mixing the hot water with boiler water in the thermal generator set, and supplying the mixture to the boiler.

8. The energy storage method of the hot water energy storage system of the thermal generator set according to claim 7, wherein the step 100 specifically comprises:

step 101, when the power grid low load requires, closing a valve E and opening a valve D and a valve B, and communicating connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

and 102, reheating incompletely expanded steam extracted from the middle part of the steam turbine by a boiler, then respectively entering cold water in a cold water storage unit through an air inlet and a liquid inlet to be mixed with the cold water in a gas-liquid mixing device to generate near-saturated hot water with certain pressure, and then storing the hot water in a hot water storage unit.

9. The energy storage method of the hot water energy storage system of the thermal generator set according to claim 8, wherein the step 200 specifically comprises:

step 201, opening a valve E, closing a valve D and a valve B, and closing connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

step 202, opening a valve C and a valve A, and communicating connecting pipelines between a water outlet end of a hot water storage unit and a thermal generator set and between a water inlet end of a cold water storage unit and the thermal generator set;

step 203, the hot water in the hot water storage unit and the cold water from the heat regenerator enter a mixing chamber together to be mixed and then are conveyed into a boiler;

step 204, the exhaust steam discharged from the steam turbine enters a condenser to be cooled into condensed water, and part of the condensed water is conveyed to a cold water storage unit to be stored;

steps 203 and 204 are repeated until the hot water in the hot water storage unit is completely released.

Technical Field

The invention relates to the technical field of thermal power generation and energy storage, in particular to a thermal generator set hot water energy storage system and method.

Background

On one hand, in order to ensure the safe and efficient operation of the thermal generator set, the power generation power of the thermal generator set is kept stable as much as possible and is close to the design load, but the power grid load is continuously fluctuated and changed due to the change of seasons, day and night, industrial production and human social activities; on the other hand, with the continuous expansion of the installed capacity of renewable energy sources, the proportion of the power supply of thermal power generation in China is smaller and smaller, and the consumption of the thermal power generation on the power supply of the renewable energy sources is required to be stronger and stronger due to the instability of the renewable energy sources (such as solar energy and wind energy). For the above reasons, the thermal power generating unit is confronted with the dilemma of low-load or even ultra-low-load operation, and needs to have increasingly strong peak shaving operation capability.

At present, some thermal generator sets are in a low-load operation state, and the problem of further reducing the load is faced in the future. The starting and stopping time of the thermal generator set is very long, the method for carrying out peak shaving by adopting the mode of starting and stopping the thermal generator set is not feasible, and the adoption of the energy storage technology is an important optional means for solving the conventional peak shaving or deep peak shaving and further promoting the ultra-low load operation of the thermal generator set.

The traditional thermal power generating set mainly comprises a boiler and a steam turbine, and has certain variable working condition adjusting capacity, but when the thermal power generating set operates at ultralow load, the lowest stable combustion load of the boiler is obviously higher than the lowest stable operation load of the steam turbine, so that when the thermal power generating set operates at ultralow load, the adjustment and storage of steam in the boiler system are mainly considered according to the characteristics of the two key systems, and the deep peak regulation and the ultralow load operation of the thermal power generating set are realized.

(CN111608890A) discloses an air energy storage system and method for a thermal power plant, when the load of a power grid is low, the redundant electric power capacity of the power plant is utilized to drive a compressor to compress and cool air and store the air in a pressure container, when the power consumption is high, the high-pressure air stored in the pressure container is heated and then is conveyed into a boiler by a blower and is mixed and combusted with coal or other fuels, and therefore a conventional boiler fan pressurization system is replaced, and the storage and the release of electric energy and peak regulation are achieved. The system has the disadvantages that the specific volume of the compressed air is still larger, and the system needs to be provided with a larger pressure container; the air compression process is a remarkable temperature rise process, much heat is lost in the cooling of hot air, and the energy storage process has multiple conversion processes of various forms of energy (steam heat energy → steam turbine mechanical energy → electric energy → compressor mechanical energy → compressed air mechanical energy), so that the comprehensive energy storage efficiency is low.

(CN110779009A) discloses an energy storage system for heating molten salt by high-temperature and high-pressure steam in a thermal power plant, which adopts high-pressure main steam and high-temperature reheat steam to heat the molten salt simultaneously, so that low-temperature molten salt is heated into high-temperature molten salt, the high-pressure main steam is cooled by the molten salt to become high-pressure condensed water, and the high-pressure condensed water is pressurized and then returns to a boiler water supply system; and the high-temperature reheated steam is cooled by molten salt to become low-temperature steam and returns to a boiler reheater. This energy storage system uses the fused salt as heat-retaining medium, and easily corrodes energy storage system, and easily takes place fused salt crystallization in the heat exchanger and blocks up the problem, and in addition, the specific heat of fused salt is slightly low, is unfavorable for reducing energy storage system's volume.

Disclosure of Invention

The invention aims to provide a hot water energy storage system and a hot water energy storage method for a thermal generator set, and aims to solve the technical problems that in the prior art, the comprehensive energy storage efficiency is low due to multiple conversion processes of various forms of energy in the energy storage process of the thermal generator set, or molten salt is used as a heat storage medium, an energy storage system is easy to corrode, and molten salt crystallization and blockage are easy to occur.

In order to solve the technical problems, the invention specifically provides the following technical scheme:

a thermal generator set hot water energy storage system comprises:

a water inlet of the cold water storage unit is connected with an outlet of a condenser of the thermal generator set;

the gas-liquid mixing device receives steam from the thermal power generating unit and cold water from the cold water storage unit and mixes the steam and the cold water to form near-saturated hot water with certain pressure;

the hot water storage unit is connected with a water outlet of the gas-liquid mixing device and used for storing near-saturated hot water and mixing the stored hot water with boiler water supply of the thermal generator set when the power load of a power grid is high;

the cold water storage unit comprises a cold water pipeline, the hot water storage unit comprises a hot water pipeline, the cold water pipeline and the hot water pipeline are jointly connected with a plurality of dual-purpose storage tanks, the dual-purpose storage tanks are used for alternately storing cold water and hot water, the cold water pipeline is at least connected with one cold water storage tank only storing cold water, and the hot water pipeline is at least connected with one hot water storage tank only storing hot water.

As a preferable scheme of the invention, the thermal generator set comprises a generator, a boiler, a steam turbine, a condenser and a heat regenerator which are sequentially connected and form a closed loop, a deaerator is arranged between the condenser and the heat regenerator and is connected with a make-up water pipe, the dead steam in the steam turbine is condensed into water through the condenser, the condensed water is conveyed into the deaerator through the first water pump, deaerated and then conveyed into the heat regenerator through the second water pump, the outlet of the heat regenerator is connected with the mixing chamber, an air extraction opening is formed in the middle of the steam turbine, the heat regenerator receives incompletely expanded steam extracted from the air extraction opening and cold water in the deaerator, the incompletely expanded steam and the cold water are conveyed to the mixing chamber to be mixed and then conveyed to the boiler through the third water pump to be heated, and the heated steam or supercritical water enters the steam turbine to expand to do work and drive the generator to generate power.

As a preferable scheme of the present invention, the middle part of the steam turbine and the boiler are connected by a loop pipe to form a closed passage, and the loop pipe includes a pipe for sending incompletely expanded steam extracted from the middle part of the steam turbine to the boiler to reheat and a delivery pipe for sending the reheated steam to the steam turbine to perform expansion work.

As a preferable scheme of the present invention, a water inlet end of the cold water pipeline is connected to a water outlet of the condenser through a pipeline, a fourth water pump and a valve a are disposed on the section of connecting pipeline, a water outlet end of the cold water pipeline is connected to a water inlet of the gas-liquid mixing device through a pipeline, and a fifth water pump and a valve B are disposed on the section of pipeline.

The water inlet end of the hot water pipeline is connected with the water outlet of the gas-liquid mixing device through a pipeline, the water outlet end of the hot water pipeline is connected with the inlet of the mixing chamber through a pipeline, and a sixth water pump and a valve C are arranged on the pipeline.

In a preferred embodiment of the present invention, an air inlet of the gas-liquid mixing device is connected to the delivery pipe to receive the steam reheated by the boiler, a valve D is provided on the connection pipe, and a valve E is further provided on a section of the delivery pipe adjacent to the steam turbine.

In a preferred embodiment of the present invention, each of the cold water storage tank, the hot water storage tank, and the dual-purpose storage tank is provided with an independent valve F for controlling water inlet and outlet.

In order to solve the above technical problems, the present invention further provides the following technical solutions:

an energy storage method of a hot water energy storage system of a thermal generator set comprises the following steps:

step 100, when the power grid is in a low-load requirement, extracting steam which is not fully expanded in a thermal generator set, mixing the steam with cold water in a cold water storage unit to form near-saturated hot water, and storing the near-saturated hot water in a hot water storage unit;

and 200, when the high load of the power grid is required, extracting hot water in the hot water storage unit, mixing the hot water with boiler water in the thermal generator set, and supplying the mixture to the boiler.

As a preferred embodiment of the present invention, step 100 specifically includes:

step 101, when the power grid requires low load, closing a valve E and opening a valve D and a valve B to conduct connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal power generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

and 102, reheating incompletely expanded steam extracted from the middle part of the steam turbine by a boiler, then respectively entering cold water in a cold water storage unit through an air inlet and a liquid inlet to be mixed with the cold water in a gas-liquid mixing device to generate near-saturated hot water with certain pressure, and then storing the hot water in a hot water storage unit.

As a preferred embodiment of the present invention, step 200 specifically includes:

step 201, opening a valve E, closing a valve D and a valve B, and closing connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

step 202, opening a valve C and a valve A, and communicating connecting pipelines between a water outlet end of a hot water storage unit and a thermal generator set and between a water inlet end of a cold water storage unit and the thermal generator set;

step 203, the hot water in the hot water storage unit and the cold water from the heat regenerator enter a mixing chamber together to be mixed and then are conveyed into a boiler;

step 204, the exhaust steam discharged from the steam turbine enters a condenser to be cooled into condensed water, and part of the condensed water is conveyed to a cold water storage unit to be stored;

steps 203 and 204 are repeated until the hot water in the hot water storage unit is completely released.

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

when the power grid low load requirement is met, incompletely expanded steam is extracted from the thermal generator set and mixed with cold water in the cold water storage unit to form saturated hot water, the saturated hot water is further stored in the hot water storage unit, and when the power grid power load is high, hot water in the hot water storage unit is extracted and mixed with boiler water at a proper position and supplied to the boiler. The energy storage technology directly stores and releases heat energy, does not have multiple conversion processes of various forms of energy, does not need a necessary cooling and heat dissipation process, and has higher comprehensive energy storage efficiency. The whole energy storage system adopts water as a working medium, and has the advantages of large specific heat capacity, environmental friendliness, good safety and low price.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

FIG. 1 is a schematic flow chart of a thermal power generating unit operating alone according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart of the embodiment of the invention when energy is stored in the hot water energy storage system of the thermal generator set;

FIG. 3 is a schematic flow chart of the embodiment of the present invention for providing energy release for the hot water energy storage system of the thermal generator set;

the reference numerals in the drawings denote the following, respectively:

10-thermal generator set; 20-a gas-liquid mixing device; 30-a cold water storage unit; 40-a hot water storage unit;

11-a boiler; 12-a steam turbine; 13-a generator; 14-a condenser; 16-a deaerator; 17-a heat regenerator; 18-a blending chamber;

31-cold water line; 32-a cold water storage tank;

41-hot water pipeline; 42-hot water storage tank;

51-a dual-purpose storage tank;

151-first water pump; 152-a second water pump; 153-third water pump; 154-fourth water pump; 155-fifth water pump; 156-sixth water pump;

191-valve a; 192-valve B; 193-valve C; 194-valve D; 195-valve E; 196-valve F.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 3, the present invention provides a hot water energy storage system of a thermal generator set, comprising:

a cold water storage unit 30, wherein a water inlet of the cold water storage unit 30 is connected with a condenser outlet of the thermal generator set 10;

a gas-liquid mixing device 20, wherein the gas-liquid mixing device 20 receives the steam from the thermal generator set 10 and the cold water from the cold water storage unit 30 and mixes the steam and the cold water to form near-saturated hot water with a certain pressure;

and the hot water storage unit 40 is connected with the water outlet of the gas-liquid mixing device 20 and is used for storing near-saturated hot water and mixing the stored hot water with boiler feed water of the thermal generator set 10 in the mixing chamber 18 when the power load of a power grid is high.

Wherein, the thermal generator set 10 comprises a generator 13, a boiler 11, a steam turbine 12, a condenser 14 and a heat regenerator 17 which are connected in sequence and form a closed loop, a deaerator 16 is arranged between the condenser 14 and the heat regenerator 17, the deaerator 16 is connected with a make-up water pipe, the dead steam in the steam turbine 12 is condensed into water by the condenser 14, the condensed water is conveyed into the deaerator 16 through the first water pump 151 to be deaerated and then conveyed into the heat regenerator 17 through the second water pump 152, the outlet of the heat regenerator 17 is connected with the blending chamber 18, an air extraction opening is formed in the middle of the steam turbine 12, the heat regenerator 17 receives incompletely expanded steam extracted from the air extraction opening and cold water in the deaerator 16, the incompletely expanded steam and the cold water are conveyed to the mixing chamber 18 to be mixed, the mixed steam and the cold water are conveyed to the boiler 11 through the third water pump 153 to be heated, and the heated steam or supercritical water enters the steam turbine 12 to be expanded to do work and drive the generator 13 to generate power.

The middle part of the steam turbine 12 and the boiler 11 are connected through a loop pipe fitting to form a closed passage, and the loop pipe fitting comprises a pipe fitting for sending incompletely expanded steam extracted from the middle part of the steam turbine 12 into the boiler 11 for reheating and a conveying pipe for sending the reheated steam into the steam turbine 12 for expansion work.

The middle outlet of the steam turbine 12 can be directly connected with the gas inlet of the gas-liquid mixing device 20 through a pipeline without passing through the boiler 11;

the gas-liquid mixing device 20 in the embodiment of the present invention may adopt an ejector, or any device capable of mixing steam and cold water, such as a gas-liquid mixer, a tee joint, etc., instead of the ejector.

Based on the existing structure of the energy storage system, the embodiment of the invention is characterized in that when the low load of the power grid is required, incompletely expanded steam is extracted from the steam turbine 12 and mixed with cold water in the cold water storage unit 30 to form saturated hot water, and the saturated hot water is further stored in the cold and hot water storage unit 40, and when the power load of the power grid is high, hot water extracted from the cold and hot water storage unit 40 is mixed with water supplied to the boiler 11 at a proper position and is supplied to the boiler 11. The energy storage technology directly stores and releases heat energy, does not have multiple conversion processes of various forms of energy, does not need a necessary cooling and heat dissipation process, and has higher comprehensive energy storage efficiency. The whole energy storage system adopts water as a working medium, and has the advantages of large specific heat capacity, environmental friendliness, good safety and low price.

The cold water storage unit 30 includes a cold water pipeline 31, the hot water storage unit 40 includes a hot water pipeline 41, the cold water pipeline 31 and the hot water pipeline 41 are jointly connected to a plurality of dual-purpose storage tanks 51, the dual-purpose storage tanks 51 are used for alternately storing cold water and hot water, the cold water pipeline 31 is at least connected to one cold water storage tank 32 only storing cold water, and the hot water pipeline 41 is at least connected to one hot water storage tank 42 only storing hot water.

An independent valve F196 for controlling the inlet and outlet of water is installed in each of the cold water tank 32, the hot water tank 42, and the dual-purpose tank 51.

The cold water storage unit 30 and the hot water storage unit 40 are different from the prior art in that the dual-purpose storage tank 51 can alternately store hot water and cold water, and compared with the cold water storage unit 30 and the hot water storage unit 40 which are separately arranged and do not intersect with each other, the dual-purpose storage tank 51 can reduce the number of tanks, thereby reducing the occupied area and the construction cost of the whole energy storage system, and being economical and environment-friendly. The specific number of the dual-purpose storage tanks 51 can be configured according to the actual energy storage requirement of the thermal generator set 10.

Furthermore, the water inlet end of the cold water pipeline 31 is connected with the water outlet of the condenser 14 through a pipeline, a fourth water pump 154 and a valve a191 are arranged on the section of connecting pipeline, the water outlet end of the cold water pipeline 41 is connected with the water inlet of the gas-liquid mixing device 20 through a pipeline, a fifth water pump 155 and a valve B192 are arranged on the section of pipeline, and when the gas-liquid mixing device adopts an ejector and the steam pressure at the ejector inlet completely has the capacity of driving the condensed water in the cold water storage unit to operate, the fifth water pump 155 in the system can be removed.

The water inlet end of the hot water pipeline 41 is connected with the water outlet of the gas-liquid mixing device 20 through a pipeline, the water outlet end of the hot water pipeline 41 is connected with the inlet of the blending chamber 18 through a pipeline, and a sixth water pump 156 and a valve C193 are arranged on the pipeline.

The gas inlet of the gas-liquid mixing device 20 is connected to the delivery pipe for receiving the steam reheated in the boiler 11, a valve D194 is provided on the connection pipe, and a valve E195 is further provided on a section of the delivery pipe close to the turbine.

As shown in fig. 2 and fig. 3, the invention further provides an energy storage method of the hot water energy storage system of the thermal generator set, which includes the following steps:

step 100, when the power grid is in a low-load requirement, extracting steam which is not fully expanded in a thermal generator set, mixing the steam with cold water in a cold water storage unit to form near-saturated hot water, and storing the near-saturated hot water in a hot water storage unit;

and 200, when the high load of the power grid is required, extracting hot water in the hot water storage unit, mixing the hot water with boiler water in the thermal generator set, and supplying the mixture to the boiler.

Wherein the steam which is not fully expanded in the thermal generator set is generated by the operation of the thermal generator set;

as shown in fig. 1, the thermal power generator set operates in a conventional operation mode, a boiler heats cold water from a third water pump into steam or supercritical water, the heated steam or supercritical water enters a steam turbine to expand and do work to drive a generator to generate power, exhaust steam in the steam turbine enters a condenser to be condensed, then is conveyed into a deaerator by a first water pump, is conveyed into a heat regenerator by a second water pump, is mixed with incompletely expanded steam extracted from a certain position in the middle of the steam turbine, and is conveyed into the boiler by the third water pump; when water needs to be supplemented, supplementing water is supplemented into the deaerator, deaerated together with circulating water from the first water pump and then conveyed into the heat regenerator by the second water pump; in the reheating process, steam extracted from a position in the middle of the steam turbine is reheated by a boiler and then is conveyed to the steam turbine to do work through expansion. The energy storage system is in a closed state;

the step 100 specifically includes:

step 101, when the power grid requires low load, closing a valve E and opening a valve D and a valve B to conduct connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal power generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

and 102, reheating incompletely expanded steam extracted from the middle part of the steam turbine by a boiler, then respectively entering cold water in a cold water storage unit through an air inlet and a liquid inlet to be mixed with the cold water in a gas-liquid mixing device to generate near-saturated hot water with certain pressure, and then storing the hot water in a hot water storage unit.

The hot water storage unit here includes two cases, i.e., the hot water storage unit has a tank with both hot water and empty tank:

the incompletely expanded steam extracted from a position in the middle of the steam turbine is reheated by a boiler (or is not reheated by the boiler) and then is conveyed into an ejector (or a gas-liquid mixer, a tee joint and the like), if residual hot water exists in the storage tank, the steam is injected and mixed into cold water from a fifth water pump in the ejector to generate near-saturated hot water with certain pressure, and the near-saturated hot water is directly stored in the storage tank in a liquid state; if the storage tank is an empty tank, the empty storage tank for storing hot water is inflated and pressurized, after the pressure is balanced, a cold water pipeline valve is opened, an ejector is adopted to inject and mix cold water from a fifth water pump, near-saturated hot water with certain pressure is generated, and then the near-saturated hot water is conveyed to the storage tank filled with steam for storage. And repeating the operation, and sequentially filling hot water into the storage tank to finish energy storage. Eventually 1 or more tanks will remain empty.

In addition, in view of the above two situations, the embodiment of the present invention further provides another storage method:

the incompletely expanded steam extracted from the middle part of the steam turbine is reheated by a boiler (or not reheated by the boiler), then is conveyed into an ejector (or a gas-liquid mixer, a tee joint and the like) to be mixed with cold water from a fifth water pump to form near saturated hot water with certain pressure, then the near saturated hot water is directly conveyed into a storage tank, and if residual hot water exists in the storage tank, the hot water can be stored in the storage tank in a liquid state; if the storage tank is empty, the hot water is firstly vaporized into steam in the storage process, the hot water is vaporized to generate more steam along with the continuous addition of the hot water, and the hot water is stored in the storage tank in a liquid state after the corresponding saturation pressure is reached. And repeating the operation, and sequentially filling hot water into the storage tank to finish energy storage. Eventually 1 or more tanks will remain empty.

The step 200 specifically includes:

step 201, opening a valve E, closing a valve D and a valve B, and closing connecting pipelines between an air inlet of a gas-liquid mixing device and a thermal generator set and between a liquid inlet of the gas-liquid mixing device and a cold water storage unit;

step 202, opening a valve C and a valve A, and communicating connecting pipelines between a water outlet end of a hot water storage unit and a thermal generator set and between a water inlet end of a cold water storage unit and the thermal generator set;

step 203, the hot water in the hot water storage unit and the cold water from the heat regenerator enter a mixing chamber together to be mixed and then are conveyed into a boiler;

step 204, the exhaust steam discharged from the steam turbine enters a condenser to be cooled into condensed water, and part of the condensed water is conveyed to a cold water storage unit to be stored;

and repeating the step 203 and the step 204 to sequentially release the hot water in the storage tank and store the cold water in the storage tank under the condition that the hot water is not directly contacted with the cold water, thereby finishing energy release. Eventually 1 or more tanks will remain empty.

The above embodiments are only exemplary embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present application and such modifications and equivalents should also be considered to be within the scope of the present application.