Coal-fired cogeneration system integrated with multi-level heat storage tank

Abstract

The utility model relates to a coal-fired cogeneration system integrated with a multi-energy-level heat storage tank. The system comprises a steam turbine power generation system, a heat supply network water heating system, a storage tank heat storage system and a heat release system. According to the energy level characteristics of the combined heat and power generation system, the high-temperature heat storage tank, the medium-temperature heat storage tank and the low-temperature heat storage tank are arranged, the high-temperature heat storage tank and the medium-temperature heat storage tank form a high-temperature heat storage unit and are mainly used for producing main steam and reheated steam, and the medium-temperature heat storage tank and the low-temperature heat storage tank form a medium-temperature heat storage unit and are mainly used for centralized heating. Compared with a traditional storage tank system, excessive heat of a medium in the medium-temperature storage tank is used for heating a medium in the low-temperature storage tank, so that energy is utilized more sufficiently. And meanwhile, the input and output energy level characteristics of the storage tank system can be remarkably improved by adding the cascade heat storage and release system, so that the advantage of cascade energy supply of combined heat and power generation is utilized, and the cycle efficiency is improved. The system can also achieve thermoelectric decoupling, and the heat supply capacity and flexibility of the combined heat and power generation system are greatly improved.

Description

Technical Field

[0001] The present invention discloses a coal-fired heat and power cogeneration system with integrated multi-level heat storage tanks, belonging to the technical field of coal-fired power generation, including a steam turbine power generation system, a heat network water heating system, a storage tank heat storage system and a storage tank heat release system. Background Art

[0002] With the increase in energy demand and the depletion of fossil energy resources, energy and environmental issues have attracted our attention. In order to reduce carbon dioxide emissions and achieve sustainable development, the position of new energy in the energy field is becoming increasingly important. In recent years, my country's new energy power generation installed capacity and power generation have increased significantly, but the proportion of power generation is still relatively low. This is mainly because renewable energy such as wind and light has randomness and volatility, as well as the thermal and electrical coupling of cogeneration, which makes it difficult for new energy power generation to be connected to the grid on a large scale.

[0003] Configuring a heat storage tank in a cogeneration unit is one of the methods to achieve thermal-electric decoupling. As an important new energy consumption technology, it is developing rapidly. The number and energy level of the heat storage tank can be flexibly set according to the energy level characteristics of the cogeneration system. The heat storage tank can not only store excess heat for heating when the unit has excess heating capacity, but also store high-temperature heat generated by electric heating devices such as electric boilers to heat boiler feed water.

[0004] According to the analysis of existing literature, it is not difficult to find that when the traditional storage tank system heats the boiler feed water, the heat of the circulating working fluid cannot be fully utilized due to the limitation of the feed water temperature. Therefore, how to fully utilize the heat of the circulating working fluid and improve the energy storage density of the storage tank system is an important direction for its technical development. Summary of the invention

[0005] In view of the shortcomings of the existing methods, the present invention provides a coal-fired cogeneration system with integrated multi-level heat storage tanks. According to the energy level characteristics of the cogeneration system, high, medium and low temperature storage tanks are set so that the storage tank system can be used for both heat supply and boiler feed water, thereby achieving the purpose of reducing coal consumption and increasing the operating flexibility of the cogeneration unit.

[0006] To achieve the above purpose, the present invention adopts the following technical solution:

[0007] A coal-fired heat and power cogeneration system with integrated multi-level heat storage tanks, characterized in that it includes a steam turbine power generation system, a heat network water heating system, a storage tank heat storage system and a storage tank heat release system;

[0008] The steam turbine power generation system comprises a boiler (15), wherein the superheater outlet of the boiler (15) is connected to the inlet of a second mixing valve (17), the other inlet of the second mixing valve (17) is connected to the cold source outlet of the auxiliary superheater (12), the outlet of the second mixing valve (17) is connected to the inlet of a high-pressure cylinder (20), the outlet of the high-pressure cylinder (20) is connected to the inlet of a second diverter valve (18), the outlet of the second diverter valve (18) is respectively connected to the reheater inlet of the boiler (15) and the cold source inlet of the auxiliary reheater (14), the inlet of a third mixing valve (19) is respectively connected to the reheater outlet of the boiler (15) and the cold source outlet of the auxiliary reheater (14), the outlet of the third mixing valve (19) is respectively connected to the inlet of an intermediate-pressure cylinder (21), the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32), and the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32). ) is connected to the steam inlet of the preheater (9) and the inlet of the third diverter valve (22); the outlet of the third diverter valve (22) is respectively connected to the inlet of the fifth diverter valve (31) and the inlet of the low-pressure cylinder (23); the outlet of the low-pressure cylinder (23) is connected to the inlet of the condenser (25); the outlet of the condenser (25) is connected to the inlet of the condensate pump (26); the outlet of the condensate pump (26) is connected to the feed water inlet of the deaerator (32); the outlet of the deaerator (32) is connected to the inlet of the feed water pump (27); the outlet of the feed water pump (27) is connected to the inlet of the fourth diverter valve (29); the outlet of the fourth diverter valve (29) is respectively connected to the cold source inlet of the preheater (9) and the feed water inlet of the boiler (15); the high-pressure cylinder (20), the medium-pressure cylinder (21), the low-pressure cylinder (23) and the generator (24) are coaxially connected;

[0009] The heating network water heating system comprises a second heat exchanger (16), wherein the cold source inlet of the second heat exchanger (16) is connected to the return water of the heating network, the cold source outlet of the second heat exchanger (16) is connected to the cold source inlet of the peak heater (28), and the cold source outlet of the peak heater (28) is connected to the heating network as the heating network water supply; the outlet of the fifth diverter valve (31) is respectively connected to the heat source inlet of the peak heater (28) and the heat source inlet of the first heat exchanger (6), the inlet of the fourth mixing valve (30) is respectively connected to the heat source outlet of the peak heater (28) and the heat source outlet of the first heat exchanger (6), and the outlet of the fourth mixing valve (30) is connected to the deaerator (32); the medium temperature storage tank (3) The medium outlet of the low-temperature storage tank is connected to the first-circulation second circulation pump (34), the outlet of the first-circulation second circulation pump (34) is connected to an interface of the third synchronization valve (35), the other two interfaces of the third synchronization valve (35) are respectively connected to the inlet of the third circulation pump (36) and an interface of the second synchronization valve (8), the other two interfaces of the second synchronization valve (8) are respectively connected to the cold source outlet of the first heat exchanger (6) and the heat source inlet of the second heat exchanger (16), the heat source outlet of the second heat exchanger (16) is connected to an interface of the first synchronization valve (7), and the other two interfaces of the first synchronization valve (7) are respectively connected to the cold source inlet of the first heat exchanger (6) and the low-temperature storage tank (5);

[0010] The storage tank heat release system comprises a high-temperature storage tank (1), wherein the outlet of the high-temperature storage tank (1) is connected to the inlet of a first circulation pump (33), the outlet of the first circulation pump (33) is connected to the inlet of a first diverter valve (13), the outlet of the first diverter valve (13) is respectively connected to the heat source inlets of an auxiliary superheater (12) and an auxiliary reheater (14), the inlet of a first mixing valve (11) is respectively connected to the heat source outlets of the auxiliary superheater (12) and the auxiliary reheater (14), the outlet of the first mixing valve (11) is connected to the heat source inlet of an evaporator (10), the heat source outlet of the evaporator (10) is connected to the heat source inlet of a preheater (9), and the heat source outlet of the preheater (9) is connected to the inlet of an intermediate-temperature storage tank (3).

[0011] The tank heat storage system comprises a low-temperature storage tank (5), the low-temperature storage tank (5) being connected to an interface of a first synchronization valve (7), the other two interfaces of the first synchronization valve (7) being respectively connected to a cold source inlet of a first heat exchanger (6) and a hot source outlet of a second heat exchanger (16), the cold source outlet of the first heat exchanger (6) being connected to an interface of a second synchronization valve (8), the other two interfaces of the second synchronization valve (8) being respectively connected to a hot source inlet of the second heat exchanger (16) and a hot source outlet of a third synchronization valve (35). The third synchronous valve (35) is connected to an inlet of the first circulation second circulation pump (34) and an inlet of the third circulation pump (36), respectively; the outlet of the third circulation pump (36) is connected to the inlet of the second electric heating device (4); the outlet of the second electric heating device (4) is connected to the inlet of the medium temperature storage tank (3); the outlet of the medium temperature storage tank (3) is connected to the inlet of the first electric heating device (2); and the outlet of the first electric heating device (2) is connected to the inlet of the high temperature storage tank (1).

[0012] The coal-fired heat and power cogeneration system with integrated multi-level heat storage tanks is characterized in that the medium-temperature storage tank (3) contains a high-temperature heat storage medium and a medium-temperature heat storage medium, and the two heat storage media exchange heat in the medium-temperature storage tank (3).

[0013] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the heat network water heating system, the mass flow rate of the heat network return water is determined by the mass flow rate of the medium-temperature heat storage medium, the steam extraction volume of the medium-pressure cylinder (21) and the diversion ratio of the fifth diverter valve (31).

[0014] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the heat release system of the storage tank, when the unit storage tank is in a heat release state, the third synchronization valve (35), the second synchronization valve (8) and the first synchronization valve (7) are all unidirectional flows, and no diversion or mixing is involved.

[0015] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, when the storage tank heat storage system is in a heat storage state, the first synchronization valve (7), the second synchronization valve (8), and the third synchronization valve (35) are all unidirectional flows, and no flow division or mixing is involved.

[0016] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the storage tank heat storage system and the heat release system, the electricity used by the first electric heating device (2) and the second electric heating device (4) includes abandoned electricity from new energy stations or excess electricity from power plants.

[0017] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the storage tank heat storage system and the heat release system, the circulating medium of the high-temperature heat storage unit includes binary solar salt, and the circulating medium of the medium-temperature heat storage unit includes synthetic organic heat transfer oil.

[0018] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that when the heat storage system heats the circulating medium of the high-temperature heat storage unit, the mass flow rate of the circulating medium is determined by the total amount of abandoned electricity.

[0019] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the tank heat storage system, the circulating medium of the medium-temperature heat storage unit can be heated by three methods: steam extraction from the medium-pressure cylinder (21), the second electric heating device (4) and the circulating medium of the high-temperature heat storage unit in the medium-temperature storage tank (3), and one or more of the heating methods can be used.

[0020] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that the temperature of the circulating medium in the storage tank heat storage system and the storage tank heat release system can be 600°C in the high-temperature storage tank (1), 300°C in the high-temperature heat storage unit in the medium-temperature storage tank (3), and 120°C in the medium-temperature heat storage unit in the low-temperature storage tank (5).

[0021] The positive beneficial effects of the present invention are:

[0022] The present invention discloses a coal-fired cogeneration system integrating a multi-level heat storage tank. According to the energy level characteristics of the cogeneration system, the present invention sets high, medium and low temperature storage tanks, divides the medium temperature storage tank into layers, and returns the high temperature heat storage medium that has heated the boiler feed water to the medium temperature storage tank to heat the low temperature heat storage medium in the medium temperature storage tank, so that the energy utilization of the high temperature heat storage medium is more sufficient, and the energy storage density of the storage tank system is increased. At the same time, the high temperature medium in the high temperature storage tank can be used to heat the boiler feed water to generate main steam, thereby reducing coal consumption. The low temperature heat storage medium in the medium temperature storage tank and the steam extraction of the medium pressure cylinder constitute a heat network water cascade heating system, which not only reduces the heat exchange loss of the heat network water heating system, but also improves the heating capacity and operation flexibility of the cogeneration system, and increases the grid-connected rate of new energy power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic structural diagram of a coal-fired heat and power cogeneration system integrating a multi-level heat storage tank.

[0024] Figure 2 This is a schematic diagram of the structure of the heat storage system of the high-temperature heat storage unit + the low-temperature heat storage unit of the present invention.

[0025] Figure 3This is a schematic diagram of the structure of the high-temperature heat storage unit heat storage + low-temperature heat storage unit heat release system of the present invention.

[0026] Figure 4 This is a schematic diagram of the structure of the high-temperature heat storage unit heat release + low-temperature heat storage unit heat storage system of the present invention.

[0027] Figure 5 This is a schematic diagram of the structure of the high-temperature heat storage unit heat release + low-temperature heat storage unit heat release system of the present invention.

[0028] In the figure: 1-high temperature storage tank 2-first electric heating device 3-medium temperature storage tank 4-second electric heating device 5-low temperature storage tank 6-first heat exchanger 7-first synchronization valve 8-second synchronization valve 9-preheater 10-evaporator 11-first mixing valve 12-auxiliary superheater 13-first diverter valve 14-auxiliary reheater 15-boiler 16-second heat exchanger 17-second mixing valve 18-second diverter valve 19-third mixing valve 20-high pressure cylinder 21-medium pressure cylinder 22-third diverter valve 23-low pressure cylinder 24-generator 25-condenser 26-condensate pump 27-feedwater pump 28-peak heater 29-fourth diverter valve 30-fourth mixing valve 31-fifth diverter valve 32-deaerator 33-first circulation pump 34-second circulation pump 35-third synchronization valve 36-third circulation pump DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and some specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides Figures 1 to 5 A coal-fired cogeneration system with an integrated multi-level heat storage tank is shown, and the system consists of a steam turbine power generation system, a heat network water heating system, a tank heat storage system and a tank heat release system.

[0031] The steam turbine power generation system comprises a boiler (15), wherein the superheater outlet of the boiler (15) is connected to the inlet of a second mixing valve (17), the other inlet of the second mixing valve (17) is connected to the cold source outlet of the auxiliary superheater (12), the outlet of the second mixing valve (17) is connected to the inlet of a high-pressure cylinder (20), the outlet of the high-pressure cylinder (20) is connected to the inlet of a second diverter valve (18), the outlet of the second diverter valve (18) is respectively connected to the reheater inlet of the boiler (15) and the cold source inlet of the auxiliary reheater (14), the inlet of a third mixing valve (19) is respectively connected to the reheater outlet of the boiler (15) and the cold source outlet of the auxiliary reheater (14), the outlet of the third mixing valve (19) is respectively connected to the inlet of an intermediate-pressure cylinder (21), the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32), and the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32). ) is connected to the steam inlet of the preheater (9) and the inlet of the third diverter valve (22); the outlet of the third diverter valve (22) is respectively connected to the inlet of the fifth diverter valve (31) and the inlet of the low-pressure cylinder (23); the outlet of the low-pressure cylinder (23) is connected to the inlet of the condenser (25); the outlet of the condenser (25) is connected to the inlet of the condensate pump (26); the outlet of the condensate pump (26) is connected to the feed water inlet of the deaerator (32); the outlet of the deaerator (32) is connected to the inlet of the feed water pump (27); the outlet of the feed water pump (27) is connected to the inlet of the fourth diverter valve (29); the outlet of the fourth diverter valve (29) is respectively connected to the cold source inlet of the preheater (9) and the feed water inlet of the boiler (15); the high-pressure cylinder (20), the medium-pressure cylinder (21), the low-pressure cylinder (23) and the generator (24) are coaxially connected;

[0032] The heating network water heating system comprises a second heat exchanger (16), wherein the cold source inlet of the second heat exchanger (16) is connected to the return water of the heating network, the cold source outlet of the second heat exchanger (16) is connected to the cold source inlet of the peak heater (28), and the cold source outlet of the peak heater (28) is connected to the heating network as the heating network water supply; the outlet of the fifth diverter valve (31) is respectively connected to the heat source inlet of the peak heater (28) and the heat source inlet of the first heat exchanger (6), the inlet of the fourth mixing valve (30) is respectively connected to the heat source outlet of the peak heater (28) and the heat source outlet of the first heat exchanger (6), and the outlet of the fourth mixing valve (30) is connected to the deaerator (32); the medium temperature storage tank (3) The medium outlet of the low-temperature storage tank is connected to the first-circulation second circulation pump (34), the outlet of the first-circulation second circulation pump (34) is connected to an interface of the third synchronization valve (35), the other two interfaces of the third synchronization valve (35) are respectively connected to the inlet of the third circulation pump (36) and an interface of the second synchronization valve (8), the other two interfaces of the second synchronization valve (8) are respectively connected to the cold source outlet of the first heat exchanger (6) and the heat source inlet of the second heat exchanger (16), the heat source outlet of the second heat exchanger (16) is connected to an interface of the first synchronization valve (7), and the other two interfaces of the first synchronization valve (7) are respectively connected to the cold source inlet of the first heat exchanger (6) and the low-temperature storage tank (5);

[0033] The heat release system comprises a high-temperature storage tank (1), wherein the outlet of the high-temperature storage tank (1) is connected to the inlet of a first circulation pump (33), the outlet of the first circulation pump (33) is connected to the inlet of a first diverter valve (13), the outlet of the first diverter valve (13) is respectively connected to the heat source inlets of an auxiliary superheater (12) and an auxiliary reheater (14), the inlet of a first mixing valve (11) is respectively connected to the heat source outlets of the auxiliary superheater (12) and the auxiliary reheater (14), the outlet of the first mixing valve (11) is connected to the heat source inlet of an evaporator (10), the heat source outlet of the evaporator (10) is connected to the heat source inlet of a preheater (9), and the heat source outlet of the preheater (9) is connected to the inlet of an intermediate-temperature storage tank (3).

[0034] The tank heat storage system comprises a low-temperature storage tank (5), the low-temperature storage tank (5) being connected to an interface of a first synchronization valve (7), the other two interfaces of the first synchronization valve (7) being respectively connected to a cold source inlet of a first heat exchanger (6) and a hot source outlet of a second heat exchanger (16), the cold source outlet of the first heat exchanger (6) being connected to an interface of a second synchronization valve (8), the other two interfaces of the second synchronization valve (8) being respectively connected to a hot source inlet of the second heat exchanger (16) and a hot source outlet of a third synchronization valve (35). The third synchronous valve (35) is connected to an inlet of the first circulation second circulation pump (34) and an inlet of the third circulation pump (36), respectively; the outlet of the third circulation pump (36) is connected to the inlet of the second electric heating device (4); the outlet of the second electric heating device (4) is connected to the inlet of the medium temperature storage tank (3); the outlet of the medium temperature storage tank (3) is connected to the inlet of the first electric heating device (2); and the outlet of the first electric heating device (2) is connected to the inlet of the high temperature storage tank (1).

[0035] The coal-fired heat and power cogeneration system with integrated multi-level heat storage tanks is characterized in that the medium-temperature storage tank (3) contains a high-temperature heat storage medium and a medium-temperature heat storage medium, and the two heat storage media exchange heat in the medium-temperature storage tank (3).

[0036] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the heat network water heating system, the mass flow rate of the heat network return water is determined by the mass flow rate of the medium-temperature heat storage medium, the steam extraction volume of the medium-pressure cylinder (21) and the diversion ratio of the fifth diverter valve (31).

[0037] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the heat release system of the storage tank, when the unit storage tank is in a heat release state, the third synchronization valve (35), the second synchronization valve (8) and the first synchronization valve (7) are all unidirectional flows, and no diversion or mixing is involved.

[0038] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, when the storage tank heat storage system is in a heat storage state, the first synchronization valve (7), the second synchronization valve (8), and the third synchronization valve (35) are all unidirectional flows, and no flow division or mixing is involved.

[0039] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the storage tank heat storage system and the heat release system, the electricity used by the first electric heating device (2) and the second electric heating device (4) includes abandoned electricity from new energy stations or excess electricity from power plants.

[0040] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that the circulating medium of the high-temperature heat storage unit includes binary solar salt, and the circulating medium of the medium-temperature heat storage unit includes synthetic organic heat transfer oil.

[0041] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that when the heat storage system heats the circulating medium of the high-temperature heat storage unit, the mass flow rate of the circulating medium is determined by the total amount of abandoned electricity.

[0042] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that, in the tank heat storage system, the circulating medium of the medium-temperature heat storage unit can be heated by three methods: steam extraction from the medium-pressure cylinder (21), the second electric heating device (4) and the circulating medium of the high-temperature heat storage unit in the medium-temperature storage tank (3), and one or more of the heating methods can be used.

[0043] The coal-fired cogeneration system with integrated multi-level heat storage tanks is characterized in that the temperature of the circulating medium in the storage tank heat storage system and the storage tank heat release system can be 600°C in the high-temperature storage tank (1), 300°C in the high-temperature heat storage unit in the medium-temperature storage tank (3), and 120°C in the medium-temperature heat storage unit in the low-temperature storage tank (5).

[0044] Finally, it should be noted that the above examples are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A coal-fired heat and power cogeneration system with integrated multi-level heat storage tanks, characterized in that: It includes steam turbine power generation system, heat network water heating system, tank heat storage system and tank heat release system; The steam turbine power generation system comprises a boiler (15), wherein the superheater outlet of the boiler (15) is connected to the inlet of a second mixing valve (17), the other inlet of the second mixing valve (17) is connected to the cold source outlet of the auxiliary superheater (12), the outlet of the second mixing valve (17) is connected to the inlet of a high-pressure cylinder (20), the outlet of the high-pressure cylinder (20) is connected to the inlet of a second diverter valve (18), the outlet of the second diverter valve (18) is respectively connected to the reheater inlet of the boiler (15) and the cold source inlet of the auxiliary reheater (14), the inlet of a third mixing valve (19) is respectively connected to the reheater outlet of the boiler (15) and the cold source outlet of the auxiliary reheater (14), the outlet of the third mixing valve (19) is respectively connected to the inlet of an intermediate-pressure cylinder (21), the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32), and the outlet of the intermediate-pressure cylinder (21) is respectively connected to the outlet of a deaerator (32). ) is connected to the steam inlet of the preheater (9) and the inlet of the third diverter valve (22); the outlet of the third diverter valve (22) is respectively connected to the inlet of the fifth diverter valve (31) and the inlet of the low-pressure cylinder (23); the outlet of the low-pressure cylinder (23) is connected to the inlet of the condenser (25); the outlet of the condenser (25) is connected to the inlet of the condensate pump (26); the outlet of the condensate pump (26) is connected to the feed water inlet of the deaerator (32); the outlet of the deaerator (32) is connected to the inlet of the feed water pump (27); the outlet of the feed water pump (27) is connected to the inlet of the fourth diverter valve (29); the outlet of the fourth diverter valve (29) is respectively connected to the cold source inlet of the preheater (9) and the feed water inlet of the boiler (15); the high-pressure cylinder (20), the medium-pressure cylinder (21), the low-pressure cylinder (23) and the generator (24) are coaxially connected; The heating network water heating system comprises a second heat exchanger (16), wherein the cold source inlet of the second heat exchanger (16) is connected to the return water of the heating network, the cold source outlet of the second heat exchanger (16) is connected to the cold source inlet of the peak heater (28), and the cold source outlet of the peak heater (28) is connected to the heating network as the heating network water supply; the outlet of the fifth diverter valve (31) is respectively connected to the heat source inlet of the peak heater (28) and the heat source inlet of the first heat exchanger (6), the inlet of the fourth mixing valve (30) is respectively connected to the heat source outlet of the peak heater (28) and the heat source outlet of the first heat exchanger (6), and the outlet of the fourth mixing valve (30) is connected to the deaerator (32); the medium temperature storage tank (3) The medium outlet of the low-temperature storage tank is connected to the first-circulation second circulation pump (34), the outlet of the first-circulation second circulation pump (34) is connected to an interface of the third synchronization valve (35), the other two interfaces of the third synchronization valve (35) are respectively connected to the inlet of the third circulation pump (36) and an interface of the second synchronization valve (8), the other two interfaces of the second synchronization valve (8) are respectively connected to the cold source outlet of the first heat exchanger (6) and the heat source inlet of the second heat exchanger (16), the heat source outlet of the second heat exchanger (16) is connected to an interface of the first synchronization valve (7), and the other two interfaces of the first synchronization valve (7) are respectively connected to the cold source inlet of the first heat exchanger (6) and the low-temperature storage tank (5); The storage tank heat release system comprises a high-temperature storage tank (1), wherein the outlet of the high-temperature storage tank (1) is connected to the inlet of a first circulation pump (33), the outlet of the first circulation pump (33) is connected to the inlet of a first diverter valve (13), the outlet of the first diverter valve (13) is respectively connected to the heat source inlets of an auxiliary superheater (12) and an auxiliary reheater (14), the inlet of a first mixing valve (11) is respectively connected to the heat source outlets of the auxiliary superheater (12) and the auxiliary reheater (14), the outlet of the first mixing valve (11) is connected to the heat source inlet of an evaporator (10), the heat source outlet of the evaporator (10) is connected to the heat source inlet of a preheater (9), and the heat source outlet of the preheater (9) is connected to the inlet of a medium-temperature storage tank (3); The tank heat storage system comprises a low-temperature storage tank (5), the low-temperature storage tank (5) being connected to an interface of a first synchronization valve (7), the other two interfaces of the first synchronization valve (7) being respectively connected to a cold source inlet of a first heat exchanger (6) and a hot source outlet of a second heat exchanger (16), the cold source outlet of the first heat exchanger (6) being connected to an interface of a second synchronization valve (8), the other two interfaces of the second synchronization valve (8) being respectively connected to a hot source inlet of the second heat exchanger (16) and a hot source outlet of a third synchronization valve (35). The third synchronous valve (35) is connected to an inlet of the first circulation second circulation pump (34) and an inlet of the third circulation pump (36), respectively; the outlet of the third circulation pump (36) is connected to the inlet of the second electric heating device (4); the outlet of the second electric heating device (4) is connected to the inlet of the medium temperature storage tank (3); the outlet of the medium temperature storage tank (3) is connected to the inlet of the first electric heating device (2); and the outlet of the first electric heating device (2) is connected to the inlet of the high temperature storage tank (1).

2. A coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: The medium-temperature storage tank (3) contains a high-temperature heat storage medium and a medium-temperature heat storage medium, and the two heat storage media exchange heat in the medium-temperature storage tank (3).

3. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the above-mentioned hot water network heating system, the mass flow rate of the hot water network return water is determined by the mass flow rate of the medium-temperature heat storage medium, the steam extraction volume of the medium-pressure cylinder (21), and the diversion ratio of the fifth diverter valve (31).

4. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the storage tank heat release system, when the unit storage tank is in a heat release state, the third synchronization valve (35), the second synchronization valve (8) and the first synchronization valve (7) are all unidirectional flows, and no flow splitting or mixing is involved.

5. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the storage tank heat storage system, when in a heat storage state, the first synchronization valve (7), the second synchronization valve (8) and the third synchronization valve (35) are all unidirectional flows, and no flow division or mixing is involved.

6. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the tank heat storage system and the heat release system, the electricity used by the first electric heating device (2) and the second electric heating device (4) includes abandoned electricity from new energy stations or excess electricity from power plants.

7. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the tank heat storage system and the heat release system, the circulating medium of the high-temperature heat storage unit includes binary solar salt, and the circulating medium of the medium-temperature heat storage unit includes synthetic organic heat transfer oil.

8. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: When the heat storage system heats the circulating medium of the high-temperature heat storage unit, the mass flow rate of the circulating medium is determined by the total amount of wasted electricity.

9. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the tank heat storage system, the circulating medium of the medium-temperature heat storage unit can be heated by three methods: steam extraction from the medium-pressure cylinder (21), the second electric heating device (4), and the circulating medium of the high-temperature heat storage unit in the medium-temperature storage tank (3), and one or more of the heating methods can be used.

10. The coal-fired heat and power cogeneration system with integrated multi-level heat storage tank according to claim 1, characterized in that: In the storage tank heat storage system and the storage tank heat release system, the circulating medium temperature can be 600°C, the circulating medium temperature of the high temperature heat storage unit in the medium temperature storage tank (3) can be 300°C, and the circulating medium temperature of the medium temperature heat storage unit in the low temperature storage tank (5) can be 120°C.

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