High and low temperature combined energy storage system and method for thermal power generating unit

Abstract

An outlet of a boiler is divided into three paths, the first path is communicated with an inlet of a high-pressure cylinder of a steam turbine, the second path is communicated with the shell side of a high-pressure heater, the third path is communicated with a pipe side inlet of a high-temperature heater, and a pipe side outlet of the high-temperature heater is divided into two paths. Wherein one path is communicated with the shell side of the auxiliary heater, the other path is communicated with the pipe side of the low-temperature heater, the shell side of the low-temperature heater is communicated with the heat release side of the hot water heat storage system, and the heat absorption side outlet of the hot water heat storage system is divided into two paths, and the other path is communicated with an inlet of the absorption heat pump after being combined with an outlet of a heat user through a pipeline. The system and the method can meet the requirements of flexible peak regulation and deep waste heat utilization of the thermal power generating unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage peak regulation of thermal power units, and relates to a high-low temperature combined energy storage system and method for thermal power units. Background Art

[0002] Energy storage technology is a technology that uses specific heat storage materials to store excess, temporarily unneeded heat in a specific heat storage device, and releases the heat for reuse when needed. This technology can not only recycle waste heat or waste heat to avoid heat waste, but also alleviate the contradiction between heat supply and demand.

[0003] At present, we should vigorously develop new heat storage technologies based on conventional power sources, such as extracted steam storage for thermal power generating units, and promote the integrated and coordinated development of sources, grids, loads and storage.

[0004] In energy storage technology, molten salt is an ideal heat storage medium. Compared with water heat storage, molten salt heat storage has a wider operating temperature range and can be used in medium and high temperature heat storage scenarios. Therefore, molten salt heat storage technology can be applied in a variety of scenarios. Compared with solid heat storage, molten salt heat storage has the advantages of stability, long life, and low heat exchange difficulty. Molten salt heat storage has the characteristics of large-scale, long-term, safe and stable, and not restricted by site selection. It is one of the most promising energy storage technologies for building future new power systems.

[0005] Hot water energy storage technology for thermal power plants has been widely used at home and abroad. It is mainly used for heat and electricity decoupling in the heating season of thermal power plants to improve the operating flexibility of heating units. The working principle is that when there is an excess of heating steam flow, the excess heat energy is converted into hot water and stored in a hot water tank. When electricity demand is at a low point, the output of the boiler and steam turbine is reduced, and the insufficient heating is supplemented by the hot water tank. When electricity demand is at a peak, the output of the boiler is increased, the external heating of the steam turbine is reduced, the top load capacity of the power plant is enhanced, and the insufficient heating is supplemented by the hot water tank.

[0006] Heat pumps are one of the effective ways to recover waste heat from power plants. They are generally divided into compression heat pumps and absorption heat pumps. As an energy-level-raising device driven by waste heat, absorption heat pumps have fewer operating parts and are easier to maintain than compression heat pumps. They only consume a small amount of electricity to recover a large amount of waste heat, and are therefore widely used in the field of regional centralized heating and cooling. Traditional absorption heat pumps consist of five main components: generator, condenser, evaporator, absorber, and heat exchanger. They use external waste heat to change the concentration of the internal solution, and the refrigerant phase changes to transfer heat, so that the cooling water temperature is increased for heating, thereby improving the utilization rate of waste heat resources. Traditional absorption heat pumps have been widely studied by scholars at home and abroad and applied to waste heat recovery in power plants. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a high and low temperature combined energy storage system and method for a thermal power unit, which can meet the needs of flexible peak regulation and deep waste heat utilization of thermal power units.

[0008] To achieve the above-mentioned object, the present invention discloses a high-low temperature combined energy storage system for a thermal power unit, comprising a boiler, a combined energy storage system, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of a steam turbine, a deaerator and a high-pressure heater; the combined energy storage system comprises a high-temperature heater, a low-temperature heater, a hot water heat storage system, a heat user, an absorption heat pump and an auxiliary heater;

[0009] The outlet of the boiler is divided into three routes, wherein the first route is connected to the inlet of the high-pressure cylinder of the steam turbine, the second route is connected to the shell side of the high-pressure heater, and the third route is connected to the tube side inlet of the high-temperature heater. The tube side outlet of the high-temperature heater is divided into two routes, wherein one route is connected to the shell side of the auxiliary heater, and the other route is connected to the tube side of the low-temperature heater. The shell side of the low-temperature heater is connected to the heat release side of the hot water heat storage system. The heat absorption side outlet of the hot water heat storage system is divided into two routes, wherein one route is connected to the inlet of the heat user, and the other route is connected to the outlet of the heat user through pipelines and then connected to the inlet of the absorption heat pump.

[0010] The outlet of the high-pressure cylinder of the steam turbine is divided into three paths, wherein the first path is connected to the inlet of the absorption heat pump, the second path is connected to the inlet of the intermediate-pressure cylinder of the steam turbine, and the third path is connected to the inlet of the deaerator.

[0011] As a further improvement of the high and low temperature combined energy storage system of the thermal power unit of the present invention,

[0012] Furthermore, it also includes a steam turbine low-pressure cylinder and a low-pressure heater, the outlet of the steam turbine intermediate-pressure cylinder is connected to the inlet of the steam turbine low-pressure cylinder, and the steam extraction port of the steam turbine intermediate-pressure cylinder is connected to the shell side of the low-pressure heater.

[0013] Furthermore, the outlet of the low-pressure cylinder of the steam turbine is connected to the inlet of the deaerator via the condenser, the condensate pump and the tube side of the low-pressure heater in sequence.

[0014] Furthermore, the outlet of the deaerator is connected to the inlet of the boiler via the feed water pump, the tube side of the auxiliary heater and the tube side of the high-pressure heater in sequence.

[0015] Furthermore, it also includes a molten salt energy storage system, and the shell side of the high-temperature heater is connected to the molten salt energy storage system.

[0016] Furthermore, the tube-side outlet of the high-temperature heater is connected to the shell side of the auxiliary heater via a second flow regulating valve.

[0017] Furthermore, the tube side outlet of the high temperature heater is connected to the tube side of the low temperature heater via a first flow regulating valve.

[0018] The present invention discloses a high-low temperature combined energy storage method for a thermal power unit, comprising the following steps:

[0019] The high-temperature superheated steam generated by the boiler enters the high-temperature heater to release heat; the steam discharged from the high-temperature heater is divided into two paths, among which the first path enters the low-temperature heater to continue to release heat and store the heat in the hot water heat storage system, and the second path enters the auxiliary heater for heating the boiler feed water. The hot water discharged from the low-temperature heater is divided into two paths, one path is directly supplied to the heat users, and the other path is mixed with the heat network return water returned from the heat users as a heat source, and then enters the absorption heat pump as a low-temperature heat source, and the exhaust steam from the high-pressure cylinder of the turbine is used as a high-temperature heat source to enter the absorption heat pump to generate hot water or steam.

[0020] As a further improvement of the high and low temperature combined energy storage method for thermal power units of the present invention,

[0021] Furthermore, it also includes a molten salt energy storage system, in which steam enters a low-temperature heater to release heat, and the heat is stored in a hot water heat storage system.

[0022] Furthermore, the tube side outlet of the high-temperature heater is connected to the shell side of the auxiliary heater via the second flow regulating valve; the tube side outlet of the high-temperature heater is connected to the tube side of the low-temperature heater via the first flow regulating valve, and the steam flow entering the auxiliary heater and the low-temperature heater is regulated by the first flow regulating valve and the second flow regulating valve.

[0023] The present invention has the following beneficial effects:

[0024] In the specific operation of the high-low temperature combined energy storage system and method for thermal power units described in the present invention, the high-temperature superheated steam generated by the boiler enters the high-temperature heater to release heat, thereby realizing the primary utilization of the steam heat; the steam discharged from the high-temperature heater is divided into two paths, wherein the first path enters the low-temperature heater to continue to release heat and store the heat in the hot water heat storage system, and the second path enters the auxiliary heater to heat the boiler feed water, thereby realizing the secondary utilization of the steam heat; the hot water discharged from the low-temperature heater is divided into two paths, one path is directly supplied to the heat user, and the other path is used as a heat source to communicate with the hot water returned from the heat user. The return water from the heat network is mixed and then enters the absorption heat pump as a low-temperature heat source. The exhaust steam from the high-pressure cylinder of the steam turbine is used as a high-temperature heat source to enter the absorption heat pump to generate hot water or steam, thereby realizing the cascade utilization of steam heat. At the same time, the molten salt energy storage system is used to peak the unit. Through the coupling effect of the hot water heat storage system and the absorption heat pump, the exhaust waste heat at the outlet of the molten salt energy storage system is deeply utilized, and the peak-shaving effect of the molten salt energy storage system on the thermal power unit is strengthened. At the same time, the waste heat of the return water from the heat network and the hot water heat storage system is further utilized, thereby improving the peak-shaving capacity and waste heat utilization efficiency of the thermal power unit.

[0025] Furthermore, the steam flow entering the auxiliary heater and the low-temperature heater is regulated by the first flow regulating valve and the second flow regulating valve, which has greater flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Among them, 1 is a boiler, 2 is a combined energy storage system, 3 is a steam turbine high-pressure cylinder, 4 is a steam turbine medium-pressure cylinder, 5 is a steam turbine low-pressure cylinder, 6 is a condenser, 7 is a condensate pump, 8 is a low-pressure heater, 9 is a deaerator, 10 is a feed water pump, 11 is a high-pressure heater, 21 is a high-temperature heater, 22 is a molten salt energy storage system, 23 is a first flow regulating valve, 24 is a low-temperature heater, 25 is a hot water heat storage system, 26 is a heat user, 27 is an absorption heat pump, 28 is a second flow regulating valve, and 29 is an auxiliary heater. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0031] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0032] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0033] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0034] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0037] Embodiment 1

[0038] The high and low temperature combined energy storage system of the thermal power unit described in the present invention comprises a boiler 1, a combined energy storage system 2, a steam turbine high pressure cylinder 3, a steam turbine medium pressure cylinder 4, a deaerator 9 and a high pressure heater 11; the combined energy storage system 2 comprises a high temperature heater 21, a low temperature heater 24, a hot water heat storage system 25, a heat user 26, an absorption heat pump 27 and an auxiliary heater 29; the outlet of the boiler 1 is divided into three routes, wherein the first route is connected to the inlet of the steam turbine high pressure cylinder 3, the second route is connected to the shell side of the high pressure heater 11, and the third route is connected to the tube side inlet of the high temperature heater 21, and the tube side outlet of the high temperature heater 21 is divided into two There are three paths, one of which is connected to the shell side of the auxiliary heater 29, and the other is connected to the tube side of the low-temperature heater 24. The shell side of the low-temperature heater 24 is connected to the heat release side of the hot water heat storage system 25. The outlet of the heat absorption side of the hot water heat storage system 25 is divided into two paths, one of which is connected to the inlet of the heat user 26, and the other is connected to the outlet of the heat user 26 through a pipeline and then connected to the inlet of the absorption heat pump 27; the outlet of the turbine high-pressure cylinder 3 is divided into three paths, among which the first path is connected to the inlet of the absorption heat pump 27, the second path is connected to the inlet of the turbine intermediate-pressure cylinder 4, and the third path is connected to the inlet of the deaerator 9.

[0039] Accordingly, the high and low temperature combined energy storage method for a thermal power unit of the present invention comprises the following steps:

[0040] The high-temperature superheated steam generated by the boiler 1 enters the high-temperature heater 21 to release heat; the steam discharged from the high-temperature heater 21 is divided into two paths, wherein the first path enters the low-temperature heater 24 to continue to release heat and stores the heat in the hot water heat storage system 25, and the second path enters the auxiliary heater 29 to heat the feed water of the boiler 1. The hot water discharged from the low-temperature heater 24 is divided into two paths, one path is directly supplied to the heat user 26, and the other path is used as a heat source to mix with the heat network return water returned from the heat user 26, and then enters the absorption heat pump 27 as a low-temperature heat source, and uses the exhaust steam extraction of the turbine high-pressure cylinder 4 as a high-temperature heat source to enter the absorption heat pump 27 to generate hot water or steam.

[0041] Embodiment 2

[0042] refer to Figure 1 The high and low temperature combined energy storage system of the thermal power unit described in the present invention includes a boiler 1, a combined energy storage system 2, a turbine high-pressure cylinder 3, a turbine medium-pressure cylinder 4, a turbine low-pressure cylinder 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feed water pump 10 and a high-pressure heater 11; the combined energy storage system 2 includes a high-temperature heater 21, a molten salt energy storage system 22, a first flow regulating valve 23, a low-temperature heater 24, a hot water heat storage system 25, a heat user 26, an absorption heat pump 27, a second flow regulating valve 28 and an auxiliary heater 29.

[0043] The outlet of the boiler 1 is divided into three routes, wherein the first route is connected to the inlet of the high-pressure cylinder 3 of the steam turbine, the second route is connected to the shell side of the high-pressure heater 11, and the third route is connected to the tube side inlet of the high-temperature heater 21. The tube side outlet of the high-temperature heater 21 is divided into two routes, one of which is connected to the shell side of the auxiliary heater 29 through the second flow regulating valve 28, and the other is connected to the tube side of the low-temperature heater 24 through the first flow regulating valve 23. The shell side of the high-temperature heater 21 is connected to the molten salt energy storage system 22, and the shell side of the low-temperature heater 24 is connected to the heat release side of the hot water heat storage system 25. The heat absorption side outlet of the hot water heat storage system 25 is divided into two routes, one of which is connected to the inlet of the heat user 26, and the other is connected to the outlet of the heat user 26 through pipelines and pipes and then connected to the inlet of the absorption heat pump 27.

[0044] The outlet of the turbine high-pressure cylinder 3 is divided into three routes, wherein the first route is connected to the inlet of the absorption heat pump 27, the second route is connected to the inlet of the turbine intermediate-pressure cylinder 4, the outlet of the turbine intermediate-pressure cylinder 4 is connected to the inlet of the turbine low-pressure cylinder 5, the steam extraction port of the turbine intermediate-pressure cylinder 4 is connected to the shell side of the low-pressure heater 8, and the third route is connected to the inlet of the deaerator 9.

[0045] The outlet of the turbine low-pressure cylinder 5 is connected to the inlet of the deaerator 9 via the condenser 6, the condensate pump 7 and the tube side of the low-pressure heater 8 in sequence, and the outlet of the deaerator 9 is connected to the inlet of the boiler 1 via the feed water pump 10, the tube side of the auxiliary heater 29 and the tube side of the high-pressure heater 11 in sequence.

[0046] When the power generation is large, the outlet steam of the boiler 1 is extracted into the combined energy storage system 2, and first releases heat in the high-temperature heater 21, and most of the heat is stored in the molten salt energy storage system 22 through the high-temperature heater 21; after heat exchange, the outlet steam of the high-temperature heater 21 is divided into two paths, one of which enters the auxiliary heater 29 through the second flow regulating valve 28 and the feed water of the boiler 1 in the high-pressure heater 11, and the other enters the low-temperature heater 24 through the first flow regulating valve 23, and the remaining heat is stored in the hot water storage system 25 through the low-temperature heater 24; the hot water in the hot water storage system 25 is divided into two paths, one of which directly enters the heat network and is sent to the heat user 26, and the other is mixed with the outlet return water of the heat user 26 to increase the temperature, and then enters the absorption heat pump 27. The absorption heat pump 27 uses the exhaust steam extraction of the high-pressure cylinder 3 of the steam turbine as the driving heat source to heat the mixed hot water to produce hot water or steam that can be further utilized.

[0047] The high and low temperature combined energy storage method for a thermal power unit of the present invention comprises the following steps:

[0048] The high-temperature superheated steam generated by the boiler 1 enters the high-temperature heater 21 to release heat, and the heat is stored in the molten salt energy storage system 22;

[0049] The steam discharged from the high-temperature heater 21 is divided into two paths, wherein the first path enters the low-temperature heater 24 to continue to release heat and stores the heat in the hot water heat storage system 25, and the second path enters the auxiliary heater 29 to be used for heating the feed water of the boiler 1. The hot water discharged from the low-temperature heater 24 is divided into two paths, one path is directly supplied to the heat user 26, and the other path is mixed with the heat network return water returned from the heat user 26 as a heat source, and then enters the absorption heat pump 27 as a low-temperature heat source, and uses the exhaust steam extracted from the high-pressure cylinder 4 of the turbine as a high-temperature heat source to enter the absorption heat pump 27 to generate hot water or steam.

[0050] It should be noted that the present invention can perform cascade utilization of the energy of the superheated steam extraction of the thermal power unit. Specifically, the present invention utilizes the high-temperature superheated steam at the outlet of the boiler 1 as the heat source of the combined energy storage system 2, and utilizes the high-temperature energy storage system and the low-temperature energy storage system to perform cascade utilization of the superheated steam, while meeting the needs of peak and frequency regulation and deep waste heat utilization of the thermal power unit, and broadening the scope of action of the energy storage system.

[0051] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0052] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A high and low temperature combined energy storage system for a thermal power unit, characterized in that: It comprises a boiler (1), a combined energy storage system (2), a steam turbine high-pressure cylinder (3), a steam turbine medium-pressure cylinder (4), a deaerator (9) and a high-pressure heater (11); the combined energy storage system (2) comprises a high-temperature heater (21), a low-temperature heater (24), a hot water heat storage system (25), a heat user (26), an absorption heat pump (27) and an auxiliary heater (29); The outlet of the boiler (1) is divided into three paths, wherein the first path is connected to the inlet of the high-pressure cylinder (3) of the steam turbine, the second path is connected to the shell side of the high-pressure heater (11), and the third path is connected to the tube side inlet of the high-temperature heater (21). The tube side outlet of the high-temperature heater (21) is divided into two paths, wherein one path is connected to the shell side of the auxiliary heater (29), and the other path is connected to the tube side of the low-temperature heater (24). The shell side of the low-temperature heater (24) is connected to the heat release side of the hot water heat storage system (25). The heat absorption side outlet of the hot water heat storage system (25) is divided into two paths, wherein one path is connected to the inlet of the heat user (26), and the other path is connected to the outlet of the heat user (26) through a pipeline and then connected to the inlet of the absorption heat pump (27). The outlet of the steam turbine high-pressure cylinder (3) is divided into three paths, wherein the first path is connected to the inlet of the absorption heat pump (27), the second path is connected to the inlet of the steam turbine intermediate-pressure cylinder (4), and the third path is connected to the inlet of the deaerator (9).

2. The high and low temperature combined energy storage system for thermal power units according to claim 1 is characterized in that: It also includes a steam turbine low-pressure cylinder (5) and a low-pressure heater (8), wherein the outlet of the steam turbine intermediate-pressure cylinder (4) is connected to the inlet of the steam turbine low-pressure cylinder (5), and the steam extraction port of the steam turbine intermediate-pressure cylinder (4) is connected to the shell side of the low-pressure heater (8).

3. The high and low temperature combined energy storage system for thermal power units according to claim 1 is characterized in that: The outlet of the low-pressure cylinder (5) of the steam turbine is connected to the inlet of the deaerator (9) via the condenser (6), the condensate pump (7) and the pipe side of the low-pressure heater (8) in sequence.

4. The high and low temperature combined energy storage system for thermal power units according to claim 1 is characterized in that: The outlet of the deaerator (9) is connected to the inlet of the boiler (1) via the feed water pump (10), the tube side of the auxiliary heater (29) and the tube side of the high-pressure heater (11) in sequence.

5. The high and low temperature combined energy storage system for thermal power units according to claim 1 is characterized in that: It also includes a molten salt energy storage system (22), and the shell side of the high-temperature heater (21) is connected to the molten salt energy storage system (22).

6. The high and low temperature combined energy storage system for thermal power units according to claim 1, characterized in that: The tube side outlet of the high temperature heater (21) is connected to the shell side of the auxiliary heater (29) via a second flow regulating valve (28).

7. The high and low temperature combined energy storage system for thermal power units according to claim 1, characterized in that: The tube side outlet of the high temperature heater (21) is connected to the tube side of the low temperature heater (24) via a first flow regulating valve (23).

8. A high and low temperature combined energy storage method for a thermal power unit, characterized in that: The high and low temperature combined energy storage system for thermal power units according to claim 1 comprises the following steps: The high-temperature superheated steam generated by the boiler (1) enters the high-temperature heater (21) to release heat; the steam discharged from the high-temperature heater (21) is divided into two paths, wherein the first path enters the low-temperature heater (24) to continue to release heat and store the heat in the hot water heat storage system (25); the second path enters the auxiliary heater (29) and is used to heat the feed water of the boiler (1); the hot water discharged from the low-temperature heater (24) is divided into two paths, one path is directly supplied to the heat user (26), and the other path is used as a heat source to mix with the heat network return water returned from the heat user (26), and then enters the absorption heat pump (27) as a low-temperature heat source, and uses the exhaust steam of the high-pressure cylinder (4) of the steam turbine as a high-temperature heat source to enter the absorption heat pump (27) to generate hot water or steam.

9. The high and low temperature combined energy storage method for thermal power units according to claim 8, characterized in that: It also includes a molten salt energy storage system (22), in which steam enters a low-temperature heater (24) to release heat, and the heat is stored in a hot water heat storage system (25).

10. The high and low temperature combined energy storage system for thermal power units according to claim 8, characterized in that: The tube side outlet of the high temperature heater (21) is connected to the shell side of the auxiliary heater (29) via the second flow regulating valve (28); the tube side outlet of the high temperature heater (21) is connected to the tube side of the low temperature heater (24) via the first flow regulating valve (23), and the steam flow entering the auxiliary heater (29) and the low temperature heater (24) is regulated by the first flow regulating valve (23) and the second flow regulating valve (28).

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