Combined heat and power system based on fused salt heat storage and control method

Abstract

The invention discloses a combined heat and power system based on fused salt heat storage and a control method, and relates to the technical field of novel energy storage. The fused salt side outlet end of a target heat exchanger in a first heat exchange system is connected with a fused salt mixer through a waste heat mixing controller, and a low-temperature fused salt tank is connected with the fused salt mixer through a low-temperature mixing controller; the low-temperature mixing control valve is used for controlling the amount of molten salt output to the molten salt mixer from the low-temperature molten salt tank. The waste heat mixing control valve is used for controlling the amount of molten salt output to the molten salt mixer by the target heat exchanger. Therefore, the amount of the low-temperature fused salt and the amount of the residual-temperature fused salt entering the fused salt mixer after heat release of the target heat exchanger can be controlled by adjusting the opening degrees of the residual-temperature mixing control valve and the low-temperature mixing controller, and the fused salt mixer is used for mixing the fused salt input from the mixing inlet end of the fused salt mixer; and the temperature of the output mixed molten salt is higher than that of the low-temperature molten salt and lower than that of the residual-temperature molten salt, so that the heat of the residual-temperature molten salt after heat release is recycled, and the heat and power cogeneration flexibility is improved.

Description

Technical Field

[0001] The present application relates to the field of novel energy storage technology, and in particular to a combined heat and power system and a control method based on molten salt heat storage. Background Art

[0002] Building a new power system with new energy as the main body can achieve efficient, reliable and safe use of renewable energy. However, renewable energy such as solar energy and wind energy are intermittent and volatile, making them difficult to be absorbed by the power grid on a large scale. They are easily turned into garbage electricity, resulting in wind and solar power abandonment. Under the current energy structure, new energy storage technologies that take into account both power system and heating needs are widely used. New energy storage technologies can effectively connect all links of source, grid and load, improve the intermittent, volatile and anti-peaking problems of new energy generation such as wind power and photovoltaic power generation, increase the proportion of new energy absorption, and improve the safety, economy and flexibility of power system operation.

[0003] Based on the advantages of molten salt heat storage technology, such as large heat storage power, long heat storage time, high heat storage parameters, high heat storage efficiency, and long service life, the abandoned electricity heating molten salt heat storage system uses the underutilized electricity such as abandoned wind and abandoned solar power or the electricity during the off-peak period of the power grid to heat the molten salt, thereby realizing the storage and utilization of thermal energy. However, the traditional combined heat and power system based on molten salt heat storage has poor flexibility in combined heat and power. Summary of the invention

[0004] In view of the above problems, this application provides a combined heat and power system and control method based on molten salt heat storage to achieve the purpose of improving the flexibility of combined heat and power. The specific scheme is as follows:

[0005] The first aspect of the present application provides a combined heat and power system based on molten salt heat storage, comprising: a heat storage subsystem and a combined heat and power subsystem;

[0006] The heat storage subsystem includes a high-temperature molten salt tank for storing high-temperature molten salt and a low-temperature molten salt tank for storing low-temperature molten salt; the cogeneration subsystem includes a low-temperature blending control valve, a residual temperature blending control valve, a first heat exchange system, a second heat exchange system, and a molten salt mixer; wherein the first heat exchange system includes a multi-stage heat exchanger, and the second heat exchange system includes at least one stage of heat exchanger;

[0007] The first heat exchange system is connected to the outlet of the high-temperature molten salt tank through the molten salt side inlet, connected to the inlet of the low-temperature molten salt tank through the molten salt side outlet, and connected to a preset power supply device through the steam-water side inlet and the steam-water side outlet;

[0008] The molten salt side outlet of at least one target heat exchanger in the first heat exchange system is connected to the residual temperature inlet of the molten salt mixer through the residual temperature mixing control valve; the target heat exchanger is a heat exchanger other than the final stage heat exchanger in the first heat exchange system; the residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer;

[0009] The outlet end of the low-temperature molten salt tank is connected to the low-temperature inlet end of the molten salt mixer through the low-temperature mixing control valve; the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer;

[0010] The outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second heat exchange system, and is used to mix the molten salt input from the mixing inlet end and output the mixed molten salt, wherein the mixing inlet end includes a low-temperature inlet end and a residual temperature inlet end;

[0011] The molten salt side outlet of the second heat exchange system is connected to the inlet of the low-temperature molten salt tank; the second heat exchange system is connected to a preset heating device through the steam-water side inlet and the steam-water side outlet.

[0012] In a possible implementation, the heat storage subsystem further includes a medium-temperature molten salt tank for storing medium-temperature molten salt, and the cogeneration subsystem further includes a medium-temperature mixing control valve;

[0013] The mixing inlet also includes a medium-temperature inlet, and the outlet of the medium-temperature molten salt tank is connected to the medium-temperature inlet of the molten salt mixer through the medium-temperature mixing control valve, and the medium-temperature mixing control valve is used to control the amount of molten salt output from the medium-temperature molten salt tank to the molten salt mixer;

[0014] The temperature of the low-temperature molten salt is a first preset temperature, the temperature of the high-temperature molten salt is a second preset temperature, and the temperature of the medium-temperature molten salt is a third preset temperature. The first preset temperature is lower than the third preset temperature and the third preset temperature is lower than the second preset temperature.

[0015] In a possible implementation, the thermal storage subsystem further includes a temperature sensor:

[0016] The temperature sensor is arranged at the outlet end of the molten salt mixer, and is used to collect the actual temperature of the mixed molten salt output by the molten salt mixer.

[0017] In a possible implementation, the first heat exchange system includes a first molten salt-steam superheater, a first molten salt-steam-water evaporator and a molten salt-water preheater connected in series; the cogeneration subsystem also includes a first series control valve and a second series control valve, the residual temperature mixing control valve includes a first residual temperature mixing control valve and a second residual temperature mixing control valve, and the residual temperature inlet end of the molten salt mixer includes a first residual temperature inlet end and a second residual temperature inlet end;

[0018] The molten salt side outlet end of the first molten salt-steam superheater is connected to the first residual temperature inlet end of the molten salt mixer through the first residual temperature mixing control valve, and is connected to the molten salt side inlet end of the first molten salt-steam evaporator through the first series control valve;

[0019] The molten salt side outlet end of the first molten salt-steam-water evaporator is connected to the second residual temperature inlet end of the molten salt mixer through the second residual temperature mixing control valve, and is connected to the molten salt side inlet end of the molten salt-water preheater through the second series control valve.

[0020] In a possible implementation, the cogeneration subsystem further includes a high-temperature control valve and a high-temperature blending control valve, and the blending inlet end of the molten salt mixer further includes a high-temperature inlet end;

[0021] The outlet end of the high-temperature molten salt tank is connected to the molten salt side inlet end of the first molten salt-steam superheater through the high-temperature control valve, and is connected to the high-temperature inlet end of the molten salt mixer through the high-temperature mixing control valve.

[0022] In one possible implementation, the second heat exchange system includes a second molten salt-steam superheater and a second molten salt-steam-water evaporator connected in series;

[0023] The cogeneration subsystem further includes a first low-temperature molten salt pump and a first bypass control valve connected in parallel, a medium-temperature molten salt pump and a second bypass control valve connected in parallel, and a high-temperature molten salt pump and a third bypass control valve connected in parallel;

[0024] The outlet end of the high-temperature molten salt tank is connected to the high-temperature control valve and the high-temperature mixing control valve respectively through the high-temperature molten salt pump; the outlet end of the low-temperature molten salt tank is connected to the low-temperature mixing control valve through the first low-temperature molten salt pump, and the outlet end of the medium-temperature molten salt tank is connected to the medium-temperature mixing control valve through the medium-temperature molten salt pump.

[0025] In a possible implementation, the heat storage subsystem further includes:

[0026] A low-temperature bypass control valve and a second low-temperature molten salt pump, a first-level electric heating control valve, a first-level electric heating molten salt heat exchanger, a medium-temperature inlet control valve, a second-level electric heating control valve, a second-level electric heating molten salt heat exchanger, a high-temperature inlet control valve, a first circuit switch, a transformer, a second circuit switch, and a third circuit switch 37 connected in parallel;

[0027] The low-temperature molten salt tank is connected to the inlet end of the first-level electrically heated molten salt heat exchanger through the second low-temperature molten salt pump and the first-level electrically heated control valve in sequence, the outlet end of the first-level electrically heated molten salt heat exchanger is connected to the medium-temperature molten salt tank through the medium-temperature inlet control valve, and is connected to the inlet end of the second-level electrically heated molten salt heat exchanger through the second-level electrically heated control valve, and the outlet end of the second-level electrically heated molten salt heat exchanger is connected to the high-temperature molten salt tank through the high-temperature inlet control valve;

[0028] The first-level electrically heated molten salt heat exchanger is connected to the secondary side of the transformer through the second circuit switch, the second-level electrically heated molten salt heat exchanger is connected to the secondary side of the transformer through the third circuit switch, and the primary side of the transformer is connected to the output end of the new energy power generation system through the first circuit switch.

[0029] The second aspect of the present application provides a control method, comprising: in a preset cogeneration operation mode, based on a preset target temperature, controlling the opening of a mixing control valve in a cogeneration system based on molten salt heat storage to adjust the amount of molten salt input to a molten salt mixer by the mixing control valve, until the difference between the actual temperature of the mixed molten salt output by the molten salt mixer and the target temperature is lower than a preset temperature error threshold, the mixing control valve comprising a low-temperature mixing control valve and a residual temperature mixing control valve;

[0030] The combined heat and power system includes a heat storage subsystem and a combined heat and power subsystem, wherein the heat storage subsystem includes a high-temperature molten salt tank for storing high-temperature molten salt and a low-temperature molten salt tank for storing low-temperature molten salt; the combined heat and power subsystem includes a low-temperature blending control valve, a residual temperature blending control valve, a first heat exchange system, a second heat exchange system, and a molten salt mixer; wherein the first heat exchange system includes a multi-stage heat exchanger, and the second heat exchange system includes at least one stage of heat exchanger;

[0031] The first heat exchange system is connected to the outlet of the high-temperature molten salt tank through the molten salt side inlet, connected to the inlet of the low-temperature molten salt tank through the molten salt side outlet, and connected to a preset power supply device through the steam-water side inlet and the steam-water side outlet; the molten salt side outlet of at least one target heat exchanger in the first heat exchange system is connected to the residual temperature inlet of the molten salt mixer through the residual temperature mixing control valve; the target heat exchanger is a heat exchanger other than the final heat exchanger in the first heat exchange system; the residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer; the low-temperature molten salt tank The outlet end is connected to the low-temperature inlet end of the molten salt mixer through the low-temperature mixing control valve; the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer; the outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second heat exchange system, which is used to mix the molten salt input from the mixing inlet end and output the mixed molten salt, and the mixing inlet end includes a low-temperature inlet end and a residual temperature inlet end; the molten salt side outlet end of the second heat exchange system is connected to the inlet end of the low-temperature molten salt tank; the second heat exchange system is connected to a preset heating device through a steam-water side inlet end and a steam-water side outlet end.

[0032] In a possible implementation, the heat storage subsystem further includes a medium-temperature molten salt tank for storing medium-temperature molten salt, and the cogeneration subsystem further includes a medium-temperature mixing control valve;

[0033] The mixing inlet also includes a medium-temperature inlet, and the outlet of the medium-temperature molten salt tank is connected to the medium-temperature inlet of the molten salt mixer through the medium-temperature mixing control valve; the temperature of the low-temperature molten salt is a first preset temperature, the temperature of the high-temperature molten salt is a second preset temperature, and the temperature of the medium-temperature molten salt is a third preset temperature, the first preset temperature is lower than the third preset temperature, and the third preset temperature is lower than the second preset temperature;

[0034] The mixing control valve also includes the medium-temperature mixing control valve.

[0035] In a possible implementation, the cogeneration subsystem further includes a high-temperature control valve and a high-temperature blending control valve, and the blending inlet end of the molten salt mixer further includes a high-temperature inlet end;

[0036] The outlet end of the high-temperature molten salt tank is connected to the first heat exchange system through the molten salt side inlet end through the high-temperature control valve, and is connected to the high-temperature inlet end of the molten salt mixer through the high-temperature mixing control valve;

[0037] The admixture control valve further comprises the high temperature admixture control valve.

[0038] By means of the above technical solution, the present application provides a combined heat and power system and control method based on molten salt heat storage, wherein the first heat exchange system includes a multi-stage heat exchanger, wherein the molten salt side outlet end of at least one target heat exchanger is connected to the molten salt mixer through a residual temperature mixing controller, and the target heat exchanger is a heat exchanger other than the final stage heat exchanger in the first heat exchange system. The low-temperature molten salt tank is connected to the molten salt mixer through a low-temperature mixing controller, and the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer. The residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer. Therefore, by adjusting the opening of the residual temperature mixing control valve and the low-temperature mixing controller, the amount of molten salt entering the molten salt mixer can be controlled by controlling the low-temperature molten salt and the residual temperature molten salt after the target heat exchanger releases heat. The molten salt mixer mixes the molten salt input into the mixing inlet of the molten salt mixer, and the temperature of the output mixed molten salt is higher than the low-temperature molten salt and lower than the residual temperature molten salt, thereby realizing the heat reuse of the residual temperature molten salt after heat release, and improving the flexibility of heating temperature regulation, further improving the flexibility of cogeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and other features, advantages and other aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0040] Figure 1 A schematic diagram of the structure of a combined heat and power system based on molten salt heat storage provided in this application;

[0041] Figure 2 A flow chart of a control method provided in this application;

[0042] Figure 3 A schematic diagram of the specific structure of a heat and power cogeneration system based on molten salt heat storage provided in this application;

[0043] Figure 4 A schematic diagram of the specific structure of another combined heat and power system based on molten salt heat storage provided in an embodiment of the present application;

[0044] Figure 5 A schematic diagram of a heat storage mode provided in an embodiment of the present application;

[0045] Figure 6 A schematic diagram of a heating operation mode provided in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of a power supply operation mode provided in an embodiment of the present application;

[0047] Figure 8A schematic diagram of a combined heat and power operation mode provided in an embodiment of the present application;

[0048] Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0049] Reference numerals:

[0050] GH-high temperature molten salt tank; GL-low temperature molten salt tank; GM-medium temperature molten salt tank; EM-medium temperature mixing control valve; EL low temperature mixing control valve; ER-residual temperature mixing control valve; ER1-first residual temperature mixing control valve; ER2-second residual temperature mixing control valve; EH-high temperature mixing control valve; M-molten salt mixer; E1-first bypass control valve; E2-high temperature control valve; E3-second bypass control valve; E4-first series control valve; E5-second series control valve; E6-third bypass control valve; H1-first heat exchange system; H2-second heat exchange system; h1-first molten salt-steam superheater; h2-first molten salt-steam-water evaporator; h3-molten salt-water preheater; h4-second molten salt-steam superheater; h5-second molten salt-steam-water evaporator; T1-temperature sensor; B1-first low temperature molten salt pump; B2-medium temperature molten salt pump; B3-high temperature molten salt pump.

[0051] 1-high temperature molten salt tank; 2-high temperature molten salt pump; 3-high temperature control valve; 4-high temperature bypass control valve; 5-first molten salt-steam superheater; 6-first molten salt-steam-water evaporator; 7-molten salt-water preheater; 8-low temperature molten salt tank; 9-high temperature mixing control valve; 10-molten salt-steam reheater; 11-first series control valve; 12-turbine high pressure cylinder; 13-turbine medium and low pressure cylinder; 14-generator; 15- Condenser; 16-condensate pump; 17-low-pressure heater; 18-deaerator; 19-energy storage power station feed water pump; 20-1st-level high-pressure heater; 21-2nd-level high-pressure heater; 22-second low-temperature molten salt pump; 23-low-temperature bypass control valve; 24-1st-level electric heating control valve; 25-1st-level electric heating molten salt heat exchanger; 26-medium-temperature inlet control valve; 27-medium-temperature molten salt tank; 28-2nd-level electric heating control valve; 29 -2-stage electrically heated molten salt heat exchanger; 30-high temperature inlet control valve; 31-new energy power generation system; 32-boosting station; 33-power grid; 34-first circuit switch; 35-transformer; 36-second circuit switch; 37-third circuit switch; 38-medium temperature molten salt pump; 39-medium temperature mixing control valve; 40-medium temperature bypass control valve; 41-second molten salt-steam superheater; 42-second molten salt-steam-water evaporator; 43-control valve; 44-control valve; 45-heating steam pipeline feed water pump; 46-feed water electric heater; 47-control valve; 48-steam-water heat exchanger; 49-control valve; 50-heating circulating water pump; 51-heat user, 52-low temperature mixing control valve, 53-first residual temperature mixing control valve; 54-molten salt mixer; 55-control valve; 57-second residual temperature mixing control valve; 58-second series control valve. DETAILED DESCRIPTION

[0052] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0053] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0054] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, which is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0055] Figure 1 A schematic diagram of the structure of a heat and power cogeneration system based on molten salt heat storage provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the combined heat and power system based on molten salt heat storage includes a heat storage subsystem and a combined heat and power subsystem.

[0056] In this embodiment, the heat storage subsystem includes a high-temperature molten salt tank GH for storing high-temperature molten salt and a low-temperature molten salt tank GL for storing low-temperature molten salt. The cogeneration subsystem includes a low-temperature mixing control valve EL, a residual temperature mixing control valve ER, a first heat exchange system H1, a second heat exchange system H2, and a molten salt mixer M. Among them, the first heat exchange system includes a multi-stage heat exchanger, and the second heat exchange system includes at least one stage of heat exchanger. It should be noted that the multi-stage heat exchanger includes a plurality of heat exchangers connected in series. Among them, the set temperature of the high-temperature molten salt is the second preset temperature, and the set temperature of the low-temperature molten salt is the first preset temperature. The first preset temperature is lower than the second preset temperature. Optionally, the working temperature of the high-temperature molten salt tank, that is, the set temperature of the high-temperature molten salt, is 570 ° C, and the working temperature of the low-temperature molten salt tank is 290 ° C, that is, the set temperature of the low-temperature molten salt is 290 ° C.

[0057] In this embodiment, the first heat exchange system is connected to the outlet of the high-temperature molten salt tank through the molten salt side inlet, connected to the inlet of the low-temperature molten salt tank through the molten salt side outlet, and connected to the preset power supply device through the steam-water side inlet and the steam-water side outlet. It should be noted that, according to the type and structure of the power supply device, the specific connection method of the first heat exchange system through the steam-water side inlet and the steam-water side outlet with the power supply device can refer to the prior art, and this embodiment does not limit it.

[0058] In this embodiment, the molten salt side outlet of at least one target heat exchanger in the first heat exchange system is connected to the residual temperature inlet of the molten salt mixer through a residual temperature mixing control valve. Wherein, the target heat exchanger is a heat exchanger other than the final heat exchanger in the first heat exchange system. Specifically, the residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer. It should be noted that the first-stage heat exchanger refers to the first-stage heat exchanger of the first heat exchange system, and the final heat exchanger refers to the last-stage heat exchanger of the first heat exchange system. The molten salt side inlet and the steam-water side outlet of the first-stage heat exchanger are respectively the molten salt side inlet and the steam-water side outlet of the first heat exchange system, and the molten salt side outlet and the steam-water side inlet of the final heat exchanger are respectively the molten salt side outlet and the steam-water side inlet of the first heat exchange system.

[0059] It should be noted that any heat exchanger inputs molten salt to be released through the molten salt side inlet, outputs the molten salt after heat release through the molten salt side outlet, inputs the medium to be heated (for example, low-temperature water) through the steam-water side inlet, and outputs the heated medium (for example, high-temperature steam) through the steam-water side outlet, thereby realizing heat energy conversion, that is, heat exchange. The specific structure and heat exchange principle of the heat exchanger can be referred to the prior art. This embodiment does not limit the specific structure, model, applicable medium of a single heat exchanger and the series structure of a multi-stage heat exchanger.

[0060] In this embodiment, the outlet end of the low-temperature molten salt tank is connected to the low-temperature inlet end of the molten salt mixer through a low-temperature mixing control valve. Specifically, the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer.

[0061] In this embodiment, the outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second heat exchange system. Specifically, the molten salt mixer is used to mix the molten salt inputted from the mixing inlet end and output the mixed molten salt. The mixing inlet end includes a low-temperature inlet end and a residual temperature inlet end. That is, the molten salt mixer is used to mix the low-temperature molten salt inputted from the low-temperature inlet end and the residual temperature molten salt inputted from the residual temperature inlet end, and output the mixed molten salt, wherein the low-temperature molten salt is the molten salt of the first preset temperature outputted from the low-temperature molten salt tank, and the residual temperature molten salt is the molten salt after releasing heat through the target heat exchanger. It can be understood that the temperature of the residual temperature molten salt is lower than that of the high-temperature molten salt and higher than that of the low-temperature molten salt.

[0062] In this embodiment, the molten salt side outlet of the second heat exchange system is connected to the inlet of the low-temperature molten salt tank, and the second heat exchange system is connected to a preset heating device through the steam-water side inlet and the steam-water side outlet. It should be noted that, according to the type and structure of the heating device, the specific connection method of the second heat exchange system through the steam-water side inlet and the steam-water side outlet with the heating device can refer to the prior art, and this embodiment does not limit it.

[0063] It can be seen from the above technical scheme that the combined heat and power system based on molten salt heat storage provided by the embodiment of the present application, the first heat exchange system includes a multi-stage heat exchanger, wherein the molten salt side outlet end of at least one target heat exchanger is connected to the molten salt mixer through a residual temperature mixing controller, and the target heat exchanger is a heat exchanger other than the final stage heat exchanger in the first heat exchange system. The low-temperature molten salt tank is connected to the molten salt mixer through a low-temperature mixing controller, and the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer. The residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer. Therefore, by adjusting the opening of the residual temperature mixing control valve and the low-temperature mixing controller, the amount of molten salt entering the molten salt mixer can be controlled by controlling the low-temperature molten salt and the residual temperature molten salt after the target heat exchanger releases heat. The molten salt mixer mixes the molten salt input into the mixing inlet of the molten salt mixer, and the temperature of the output mixed molten salt is higher than the low-temperature molten salt and lower than the residual temperature molten salt, thereby realizing the heat reuse of the residual temperature molten salt after heat release, and improving the flexibility of heating temperature regulation, further improving the flexibility of cogeneration.

[0064] Further, based on Figure 1 The combined heat and power system based on molten salt heat storage shown in the embodiment of the present application provides a control method. Figure 2 A flow chart of a control method provided in an embodiment of the present application is shown in FIG. Figure 2 The method specifically includes:

[0065] S201. In a preset cogeneration operation mode, in response to reaching a blending timing, a target molten salt amount corresponding to each blending control valve is calculated based on a target temperature and the temperature of the molten salt flowing through each blending control valve.

[0066] In this embodiment, the combined heat and power system based on molten salt heat storage starts the combined heat and power operation mode when the power supply operation mode and the heating operation mode are triggered at the same time. The mixing timing includes that the target temperature is not equal to the temperature of any molten salt flowing through each mixing control valve.

[0067] In this embodiment, the mixing control valve includes a low-temperature mixing control valve and a residual temperature mixing control valve. The molten salt flowing through the low-temperature mixing control valve is a low-temperature molten salt, the temperature of which is a first preset temperature, and the molten salt flowing through the residual temperature mixing control valve is a residual temperature molten salt after the target heat exchanger releases heat, the temperature of which is a preset residual temperature.

[0068] S202. Based on the target molten salt amount, control the opening of each blending control valve until the difference between the actual temperature of the blended molten salt output by the molten salt mixer and the target temperature is lower than a preset temperature error threshold.

[0069] It can be seen from the above technical scheme that a control method provided in an embodiment of the present application controls the opening of a mixing control valve in a combined heat and power system based on molten salt heat storage based on a preset target temperature under a preset combined heat and power operation mode, so as to adjust the amount of molten salt input to the molten salt mixer by the mixing control valve until the difference between the actual temperature of the mixed molten salt and the target temperature is lower than the temperature error threshold, thereby realizing the heat reuse of the residual temperature molten salt after heat release, and improving the flexibility of heating temperature regulation, thereby further improving the flexibility of combined heat and power.

[0070] Figure 3 A schematic diagram of a specific structure of a heat and power cogeneration system based on molten salt heat storage provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, the combined heat and power system based on molten salt heat storage includes a heat storage subsystem and a combined heat and power subsystem.

[0071] In this embodiment, the heat storage subsystem includes a high-temperature molten salt tank GH for storing high-temperature molten salt, a low-temperature molten salt tank GL for storing low-temperature molten salt, and a medium-temperature molten salt tank GM for storing medium-temperature molten salt. Among them, the temperature of the low-temperature molten salt is the first preset temperature, the temperature of the medium-temperature molten salt is the third preset temperature, and the temperature of the high-temperature molten salt is the second preset temperature. The first preset temperature is lower than the third preset temperature and the third preset temperature is lower than the second preset temperature. Specifically, the working temperature of the high-temperature molten salt tank, that is, the set temperature of the high-temperature molten salt, is 570°C, and the working temperature of the low-temperature molten salt tank is 290°C, that is, the set temperature of the low-temperature molten salt is 290°C. The working temperature of the medium-temperature molten salt tank, that is, the set temperature of the medium-temperature molten salt, is 390°C, and the working temperature of the medium-temperature molten salt tank is 390°C.

[0072] In this embodiment, the cogeneration subsystem includes a low-temperature mixing control valve EL, a medium-temperature mixing control valve EM, a residual temperature mixing control valve, a high-temperature control valve E2, a high-temperature mixing control valve EH, a first heat exchange system, a second heat exchange system, a first series control valve E4, a second series control valve E5, a molten salt mixer M, and a temperature sensor T1. Among them, the first heat exchange system includes a first molten salt-steam superheater h1, a first molten salt-steam evaporator h2, and a molten salt-water preheater h3 connected in series. The second heat exchange system includes a second molten salt-steam superheater h4 and a second molten salt-steam evaporator h5 connected in series. The residual temperature mixing control valve includes a first residual temperature mixing control valve ER1 and a second residual temperature mixing control valve ER2.

[0073] In this embodiment, the mixing inlet end of the molten salt mixer includes a high-temperature inlet end, a residual temperature inlet end and a low-temperature inlet end, wherein the residual temperature inlet end includes a first residual temperature inlet end and a second residual temperature inlet end.

[0074] In this embodiment, the outlet end of the high-temperature molten salt tank is connected to the molten salt side inlet end of the first molten salt-steam superheater through a high-temperature control valve, and is connected to the high-temperature inlet end of the molten salt mixer through a high-temperature mixing control valve. The molten salt side outlet end of the first molten salt-steam superheater is connected to the first residual temperature inlet end of the molten salt mixer through a first residual temperature mixing control valve, and is connected to the molten salt side inlet end of the first molten salt-steam evaporator through a first series control valve. The molten salt side outlet end of the first molten salt-steam evaporator is connected to the second residual temperature inlet end of the molten salt mixer through a second residual temperature mixing control valve, and is connected to the molten salt side inlet end of the molten salt-water preheater through a second series control valve. The molten salt side outlet end of the molten salt-water preheater is connected to the inlet end of the low-temperature molten salt tank, and the steam-water side inlet end of the molten salt-water preheater and the steam-water side outlet end of the first molten salt-steam superheater are connected to a preset power supply device.

[0075] Specifically, the first residual temperature mixing control valve is used to control the amount of molten salt output from the first molten salt-steam superheater to the molten salt mixer, and the first series control valve is used to control the amount of molten salt output from the first molten salt-steam superheater to the first molten salt-steam evaporator. The second residual temperature mixing control valve is used to control the amount of molten salt output from the first molten salt-steam evaporator to the molten salt mixer, and the second series control valve is used to control the amount of molten salt output from the first molten salt-steam evaporator to the molten salt-water preheater.

[0076] In this embodiment, the outlet of the low-temperature molten salt tank is connected to the low-temperature inlet of the molten salt mixer through a low-temperature mixing control valve. The outlet of the medium-temperature molten salt tank is connected to the medium-temperature inlet of the molten salt mixer through a medium-temperature mixing control valve. The temperature sensor is arranged at the outlet of the molten salt mixer.

[0077] Specifically, the low-temperature blending control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer. The medium-temperature blending control valve is used to control the amount of molten salt output from the medium-temperature molten salt tank to the molten salt mixer. The temperature sensor is used to collect the actual temperature of the blended molten salt output by the molten salt mixer.

[0078] In this embodiment, the outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second molten salt-steam superheater. Specifically, the molten salt mixer is used to mix the molten salt input from the mixing inlet end and output the mixed molten salt. The molten salt side outlet end of the second heat exchange system is connected to the inlet end of the low-temperature molten salt tank. The second heat exchange system is connected to a preset heating device through the steam-water side inlet end and the steam-water side outlet end.

[0079] Specifically, the molten salt mixer is used to mix at least two molten salts among the first residual temperature molten salt inputted from the first residual temperature inlet, the second residual temperature molten salt inputted from the second residual temperature inlet, the high temperature molten salt inputted from the high temperature inlet, and the low temperature molten salt inputted from the low temperature inlet, and output the mixed molten salt to the second heat exchange system. Among them, the low temperature molten salt is the molten salt of the first preset temperature outputted from the low temperature molten salt tank, the first residual temperature molten salt is the molten salt of the first residual temperature after heat release through the first molten salt-steam superheater, the second residual temperature molten salt is the molten salt of the second residual temperature after heat release through the first molten salt-steam evaporator, and the high temperature molten salt is the molten salt of the first preset temperature outputted from the high temperature molten salt tank. The temperatures from high to low are the first preset temperature, the first residual temperature temperature, the second residual temperature temperature, the third preset temperature, and the second preset temperature.

[0080] like Figure 3 As shown, the cogeneration subsystem further includes a first low-temperature molten salt pump B1 and a first bypass control valve E1 connected in parallel, a medium-temperature molten salt pump B2 and a second bypass control valve E3 connected in parallel, and a high-temperature molten salt pump B3 and a third bypass control valve E6 connected in parallel.

[0081] In this embodiment, the outlet end of the high temperature molten salt tank is connected to the high temperature control valve and the high temperature mixing control valve respectively through the high temperature molten salt pump. The outlet end of the low temperature molten salt tank is connected to the low temperature mixing control valve through the first low temperature molten salt pump, and the outlet end of the medium temperature molten salt tank is connected to the medium temperature mixing control valve through the medium temperature molten salt pump.

[0082] It can be seen from the above technical solution that through the specific structure of the combined heat and power system based on molten salt heat storage provided in the embodiment of the present application, when it is necessary to assist the peak load of the power grid, the high-temperature molten salt stored in the high-temperature molten salt tank flows through the first heat exchange system under the drive of the molten salt pump, and provides thermal energy to the power supply device through the three-stage heat exchanger, so that the power supply device generates electricity.

[0083] When it is necessary to provide heat to heat users, the molten salt for heating output by the molten salt mixer flows through the second heat exchange system, and the steam generated is used to provide heat to the heating device. Among them, the molten salt mixer can input molten salt of a single temperature. For example, the medium-temperature molten salt stored in the medium-temperature molten salt tank flows into the molten salt mixer under the drive of the medium-temperature molten salt pump, or molten salts of different temperatures can be input and output after mixing the molten salts of different temperatures. For example, the low-temperature molten salt stored in the low-temperature molten salt tank flows into the molten salt mixer under the drive of the low-temperature molten salt pump, and the high-temperature molten salt stored in the high-temperature molten salt tank flows into the molten salt mixer under the drive of the high-temperature molten salt pump. The molten salt mixer mixes the low-temperature molten salt and the high-temperature molten salt to obtain a mixed molten salt, that is, molten salt for heating. Among them, the amount of molten salt of each temperature flowing into the molten salt mixer is controlled by the mixing control valve arranged after each molten salt pump.

[0084] When it is necessary to assist the grid in peak load regulation and provide heat to heat users at the same time, since the first heat exchange system performs heat exchange in the power generation process through the three-stage heat exchanger, the input of the molten salt mixer can also include residual temperature molten salt after heat release through the first molten salt-steam superheater and / or the first molten salt-steam-water evaporator, which further improves the flexibility of adjusting the temperature of the mixed molten salt, and improves the energy storage efficiency and operation flexibility, thereby promoting the construction of a new power system for the energy base.

[0085] Figure 4 A schematic diagram of a specific structure of a heat and power cogeneration system based on molten salt heat storage provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, the system includes: a heat storage subsystem and a combined heat and power subsystem.

[0086] like Figure 4 As shown, the heat storage subsystem includes a low-temperature molten salt tank 8, a medium-temperature molten salt tank 27, a high-temperature molten salt tank 1, a low-temperature bypass control valve 23 and a second low-temperature molten salt pump 22 in parallel, a first-level electric heating control valve 24, a first-level electric heating molten salt heat exchanger 25, a medium-temperature inlet control valve 26, a second-level electric heating control valve 28, a second-level electric heating molten salt heat exchanger 29, a high-temperature inlet control valve 30, a first circuit switch 34, a transformer 35, a second circuit switch 36, and a third circuit switch 37.

[0087] In this embodiment, the low-temperature molten salt tank is connected to the inlet end of the first-level electric heating molten salt heat exchanger through the second low-temperature molten salt pump and the first-level electric heating control valve in sequence, and the outlet end of the first-level electric heating molten salt heat exchanger is connected to the medium-temperature molten salt tank through the medium-temperature inlet control valve, and is connected to the inlet end of the second-level electric heating molten salt heat exchanger through the second-level electric heating control valve, and the outlet end of the second-level electric heating molten salt heat exchanger is connected to the high-temperature molten salt tank through the high-temperature inlet control valve. The first-level electric heating molten salt heat exchanger is connected to the secondary side of the transformer through the second circuit switch, the second-level electric heating molten salt heat exchanger is connected to the secondary side of the transformer through the third circuit switch, and the primary side of the transformer is connected to the output end of the new energy power generation system through the first circuit switch. It should be noted that the new energy power generation system outputs the generated electricity through the output end, and sends the generated electricity booster station 32 to the power grid 33. The new energy power generation system includes a wind-solar combined power generation system, and the specific wind-solar combined power generation system structure can refer to the prior art.

[0088] like Figure 4As shown, the power supply subsystem for power supply in the combined heat and power subsystem includes a high-temperature molten salt tank 1, a high-temperature molten salt pump 2, a high-temperature control valve 3, a high-temperature bypass control valve 4, a first molten salt-steam superheater 5, a first molten salt-steam-water evaporator 6, a molten salt-water preheater 7, a low-temperature molten salt tank 8, a high-temperature mixing control valve 9, a molten salt-steam reheater 10, a first series control valve 11, a second series control valve 58, a steam turbine high-pressure cylinder 12, a steam turbine medium-low pressure cylinder 13 and a generator 14. Among them, the steam turbine also includes a feedwater extraction preheating circuit, including: a condenser 15, a condensate pump 16, a low-pressure heater 17, a deaerator 18, a storage power station feedwater pump 19, a first-level high-pressure heater 20, a second-level high-pressure heater 21, and a control valve 55.

[0089] In this embodiment, the high-temperature molten salt in the high-temperature molten salt tank is transported in two ways at the outlet of the high-temperature molten salt pump. One way returns to the low-temperature molten salt tank through the high-temperature control valve, the first molten salt-steam superheater, the first molten salt-steam-water evaporator and the molten salt-water preheater, and the other way passes through the high-temperature mixing control valve and the molten salt-steam reheater and is connected to the molten salt side inlet of the first molten salt-steam-water evaporator.

[0090] In this embodiment, the steam turbine works to drive the generator to generate electricity, and the steam after work enters the condenser, the condenser outlet and the condensate pump, the low-pressure heater, the deaerator, the energy storage power station feed pump, the first-stage high-pressure heater, the second-stage high-pressure heater 21 in sequence, and enters the molten salt-water preheater through the control valve.

[0091] like Figure 4 As shown, the heating subsystem for heating in the combined heat and power subsystem includes: a heating steam pipeline and a heating water absorption pipeline.

[0092] In this embodiment, the molten salt side of the heating steam pipeline is composed of a high-temperature molten salt tank 1, a high-temperature molten salt pump 2, a first molten salt-steam superheater 5, a first molten salt-steam-water evaporator 6, a molten salt-water preheater 7, a low-temperature molten salt tank 8, a high-temperature mixing control valve 9, a first series control valve 11, a second series control valve 58, a first residual temperature mixing control valve 53, a second residual temperature mixing control valve 57, a medium-temperature molten salt tank 27, a medium-temperature molten salt pump 38, a medium-temperature mixing control valve 39, a medium-temperature bypass control valve 40, a second molten salt-steam superheater 41, a second molten salt-steam-water evaporator 42, and a molten salt mixer 54.

[0093] The medium-temperature molten salt pump is connected to the molten salt mixer through the medium-temperature mixing control valve. The outlet of the high-temperature molten salt pump passes through the high-temperature control valve, the first molten salt-steam superheater, the first molten salt-steam evaporator, the first series control valve, the molten salt-water preheater and the low-temperature molten salt tank in the pipeline. The outlet of the high-temperature molten salt pump is connected to the molten salt mixer through the high-temperature mixing valve control valve, the outlet of the first molten salt-steam superheater is connected to the molten salt mixer through the first residual temperature mixing control valve, and the outlet of the first molten salt-steam evaporator is connected to the molten salt mixer through the second residual temperature mixing control valve.

[0094] The outlet of the molten salt mixer is connected to the second molten salt-steam superheater and the molten salt-steam evaporator of the heating system in sequence, and the molten salt that has completed heat release returns to the low-temperature molten salt tank. A temperature sensor is configured at the outlet of the molten salt mixer to collect the actual temperature of the mixed molten salt.

[0095] In this embodiment, the outlet of the condensate pump 16 is divided into two routes. One route is sent to the molten salt-water preheater 7 as feed water after being heated by extraction steam, and the other route is sent to the second molten salt-steam-water evaporator for heat exchange with the molten salt through the control valve 43 and the heating steam pipeline feed water pump 45 and the feed water electric heater 46.

[0096] In this embodiment, the heat-supply water heat absorption pipeline is composed of a steam-water heat exchanger 48, a control valve 49, a heat-supply circulating water pump 50 and a heat user 51. The low-temperature feed water from the heat user is sent to the steam-water heat exchanger 48 for heat absorption through the heat-supply circulating water pump, and the water after heat absorption is returned to the heat user for use through the control valve 49. Among them, the steam for heating the feed water comes from the second molten salt-steam superheater, and the steam is sent to the steam-water heat exchanger through the control valve 47.

[0097] It can be seen from the above technical scheme that the embodiment of the present application provides a combined heat and power system based on molten salt heat storage. Through the electric heating molten salt heat storage where photovoltaic / wind power cannot be connected to the Internet, the power of the electric heating molten salt heat exchange is controlled. The low-temperature molten salt stored in the low-temperature molten salt tank in the heat storage subsystem is driven by the low-temperature molten salt pump and flows through the first-level molten salt electric heater and the second-level molten salt electric heater in sequence. It is heated by the abandoned electricity of new energy, and the medium-temperature molten salt produced is returned to the medium-temperature molten salt tank for storage, and the high-temperature molten salt produced is returned to the high-temperature molten salt tank for storage, so as to construct a flexibly adjustable combined heat and power storage power station. By using abandoned electricity for heating, large-capacity and high-efficiency molten salt heat storage is realized, and at the same time, the energy advantages of molten salts at different temperatures are fully utilized to realize the secondary consumption and full utilization of clean energy in a shifted time, which is used to support the peak load regulation of the power grid and regional heating of the power system. It constitutes an independent combined heat and power supply station, which is completely decoupled from the coal-fired unit. Its main application scenario is the new energy base, which stores the abandoned electricity of new energy and uses the stored energy for power generation / heating when needed.

[0098] When it is necessary to assist the power grid in peak load regulation, the high-temperature molten salt stored in the high-temperature molten salt tank, driven by the molten salt pump, flows through the molten salt-steam-water heat exchanger to heat the feed water from the high-pressure heater of the steam turbine, generating high-temperature and high-pressure main steam which is sent to the high-pressure cylinder of the steam turbine to perform work. At the same time, part of the high-temperature molten salt is sent to the molten salt-steam-water superheater to heat the exhaust steam of the high-pressure cylinder of the steam turbine. The reheated steam is sent to the intermediate-pressure cylinder of the steam turbine to perform work. The electricity generated can be used to access the grid or supplement factory electricity.

[0099] When it is necessary to supply heat to heat users, the molten salt for heating output by the molten salt mixer flows through the second molten salt-steam-water heat exchanger, and the generated steam is sent to the first station of the heat network to heat the circulating water of users. Among them, the molten salt mixer can input molten salt of a single temperature. For example, the medium-temperature molten salt stored in the medium-temperature molten salt tank flows into the molten salt mixer under the drive of the medium-temperature molten salt pump, or molten salts of different temperatures can be input and output after mixing the molten salts of different temperatures. For example, the low-temperature molten salt stored in the low-temperature molten salt tank flows into the molten salt mixer under the drive of the low-temperature molten salt pump, and the high-temperature molten salt stored in the high-temperature molten salt tank flows into the molten salt mixer under the drive of the high-temperature molten salt pump. The molten salt mixer mixes the low-temperature molten salt and the high-temperature molten salt to obtain a mixed molten salt, that is, molten salt for heating. Among them, the amount of molten salt of each temperature flowing into the molten salt mixer is controlled by the mixing control valve arranged after each molten salt pump.

[0100] When it is necessary to assist the grid in peak load regulation and provide heat to heat users at the same time, since the first heat exchange system performs heat exchange in the power generation process through the three-stage heat exchanger, the input of the molten salt mixer can also include residual temperature molten salt after heat release through the first molten salt-steam superheater and / or the first molten salt-steam-water evaporator, which further improves the flexibility of adjusting the temperature of the mixed molten salt, and improves the energy storage efficiency and operation flexibility, and promotes the construction of a new power system for the energy base.

[0101] Furthermore, a heat and power cogeneration system based on molten salt heat storage provided in an embodiment of the present application can enter different operating modes by controlling various control valves, and the operating modes include heat storage mode, power supply mode, heating mode and heat and power cogeneration mode.

[0102] Figure 5 A schematic diagram of a heat storage mode adopted in the embodiment of the present application is shown in FIG. Figure 5 As shown, the heat storage mode is realized through the heat storage subsystem based on the combined heat and power system.

[0103] like Figure 5As shown, the electricity generated by the new energy power generation system 31 is first pressurized by the booster station 32 and then sent to the power grid 33. However, during the period of excess electricity in the new energy power generation system 31, a branch is set in front of the booster station 32, which is connected to the transformer 35 through the first circuit switch 34. After the transformer 35, it is divided into two paths. One path is connected to the first-level electric heating molten salt heat exchanger 25 through the second circuit switch 35 to supply power to the first-level electric heating molten salt heat exchanger. One path is connected to the second-level electric heating molten salt heat exchanger 29 through the third circuit switch 37 to supply power to the second-level electric heating molten salt heat exchanger.

[0104] The low-temperature molten salt tank 8 is connected to the low-temperature molten salt pump 22, the first-level electric heating control valve 24, and the first-level electric heating molten salt heat exchanger 25 in sequence. The first-level electric heating molten salt heat exchanger is used to use electric energy to heat the input low-temperature molten salt to the third preset temperature, and then output the medium-temperature molten salt at the third preset temperature. The outlet of the first-level electric heating molten salt heat exchanger 25 is divided into two routes, one of which is connected to the medium-temperature molten salt tank 27 through the medium-temperature inlet control valve 26, and is used to input the medium-temperature molten salt into the medium-temperature molten salt tank for storage. One route is connected to the high-temperature molten salt tank 1 through the second-level electric heating control valve 28, the second-level electric heating molten salt heat exchanger 29, and the high-temperature inlet control valve 30. The second-level electric heating molten salt heat exchanger is used to use electric energy to heat the input medium-temperature molten salt to the first preset temperature, and then output the high-temperature molten salt at the first preset temperature to the high-temperature molten salt tank for storage.

[0105] In summary, in the heat storage mode of the combined heat and power system based on molten salt heat storage, the low-temperature molten salt stored in the low-temperature molten salt tank is driven by the low-temperature molten salt pump and flows through the first-stage electric heating molten salt heat exchanger and the second-stage electric heating molten salt heat exchanger in sequence. The power provided by the electric heating circuit heats the molten salt in sequence, and the molten salt temperature is controlled by controlling the power of the heater. The medium-temperature molten salt generated by the first-stage electric heating molten salt heat exchanger is stored in the medium-temperature molten salt tank, and the high-temperature molten salt generated by the first and second-stage electric heating molten salt heat exchangers is stored in the high-temperature molten salt tank.

[0106] It can be seen from the above technical scheme that the series structure of the 1st-stage electric heating molten salt heat exchanger and the 2nd-stage electric heating molten salt heat exchanger in the heat storage subsystem is used to heat the low-temperature molten salt to different preset temperatures through two-stage electric heating, and send the molten salts of different temperatures to molten salt tanks of different temperatures for storage. Therefore, the combined heat and power system based on molten salt heat storage heats the molten salt heat storage by recycling the heat generated by the abandoned electricity of new energy, improves the utilization rate of new energy power generation, shifts the time utilization of excess new energy power generation, and increases the proportion of new energy power access to the power grid.

[0107] In this embodiment, the heating operation mode is triggered to operate independently by adjusting the opening and closing of each control valve and heat exchanger. Figure 6 A schematic diagram of a heating operation mode adopted in the embodiment of the present application is shown in FIG. Figure 6 As shown, the combined heat and power system based on molten salt heat storage realizes the heating operation mode through the molten salt heating subsystem.

[0108] In the first heating operation mode:

[0109] On the molten salt side, the medium-temperature molten salt in the medium-temperature molten salt tank is driven by the medium-temperature molten salt pump and sent to the molten salt mixer, the second molten salt-steam superheater, and the second molten salt-steam evaporator in sequence through the medium-temperature mixing control valve, and the molten salt after heat release returns to the low-temperature molten salt tank. Among them, the molten salt mixer does not perform the mixing function in the first heating operation mode, and the input and output molten salts are both single molten salts.

[0110] On the steam side: a branch is set after the condensate pump 16, which is sent to the inlet of the feed water pump 45 through the control valve 43, and then sent to the second molten salt-steam evaporator after being heated by the feed water electric heater 46. The steam at the outlet of the second molten salt-steam superheater is sent to the molten salt-water heat exchanger 48, and the water after heat release is sent to the inlet of the feed water pump 45, forming a closed cycle.

[0111] Heat user side: driven by the heating circulating water pump, the circulating water of the heat user is sent to the molten salt-water heat exchanger for heat absorption, and then sent to the heat user for use.

[0112] Specifically, the feed water from the condensate pump 16 is sent to the inlet of the feed water pump 45 through the control valve 43, and is connected to the feed water electric heater 46, the second heating system molten salt-steam-water evaporator 42 and the second molten salt-steam superheater 41 in sequence through the outlet of the heating system feed water pump 45, and exchanges heat with the molten salt to generate superheated steam. The generated superheated steam is sent to the steam-water heat exchanger 48 to heat the heating circulating water from the heat user 51. The steam after releasing heat is condensed into water and returned to the inlet of the feed water pump 45.

[0113] In the second heating operation mode:

[0114] On the molten salt side, the low-temperature molten salt in the low-temperature molten salt tank is driven by the low-temperature molten salt pump and sent to the molten salt mixer through the low-temperature mixing control valve 52. The high-temperature molten salt in the high-temperature molten salt tank is driven by the high-temperature molten salt pump and sent to the molten salt mixer through the high-temperature mixing control valve. After the molten salt mixer mixes the low-temperature molten salt and the high-temperature molten salt, the mixed molten salt is sent to the second molten salt-steam superheater and the second molten salt-steam-water evaporator in sequence, and the molten salt after heat release returns to the low-temperature molten salt tank.

[0115] It should be noted that the molten salt heating water supply is a closed system during normal operation, and there is no need for a large amount of water replenishment. When the heating steam pipeline is started for the first time, the condensate pump is sent to the inlet of the water pump 45 through the control valve 43. At this time, the water temperature does not meet the system requirements, and the water supply electric heater 46 needs to be turned on. When the heating steam pipeline is in continuous operation, there is no need to heat the water supply or make additional water replenishment. The control valve 43 and the water supply electric heater 46 are closed. In summary, the high-temperature water supply of the molten salt-steam-water heat exchanger in the heating system is a closed cycle, which only requires a large amount of water supply during the first startup, and only a small amount of water replenishment is required subsequently. When the independent molten salt heat storage power station is in operation, it is started for the first time. The water supply comes from the outlet of the high-pressure heater. At this time, the water supply electric heater does not work. When the independent molten salt heat storage power station is not in operation, the water supply comes from the outlet of the condensate pump, and after being heated by the electric heater, it is sent to the second molten salt-steam-water heat exchanger for continued heat absorption.

[0116] It can be seen from the above technical solution that in the heating operation mode, the high temperature of the second molten salt-steam-water heat exchanger is provided by the medium-temperature molten salt tank, or the high-temperature molten salt is provided after being mixed with the low-temperature molten salt in the low-temperature molten salt tank through the molten salt mixer. Therefore, the opening of the medium-temperature mixing control valve, the low-temperature mixing control valve, and the high-temperature mixing control valve can be adjusted according to the target temperature on the heat user side to adjust the amount of molten salt of each temperature entering the molten salt mixer in the heating operation mode, thereby adjusting the molten salt temperature at the inlet of the second molten salt-steam-water heat exchanger. It can be seen that this system can provide heating flexibility in the heating operation mode.

[0117] In this embodiment, when auxiliary peak load regulation is needed, the power supply operation mode is triggered to operate independently by adjusting the opening and closing of each control valve and heat exchanger. Figure 7 A schematic diagram of a power supply operation mode adopted in an embodiment of the present application is shown in FIG. Figure 7 As shown, the combined heat and power system based on molten salt heat storage realizes the power supply operation mode through the molten salt steam-water power generation subsystem.

[0118] In this embodiment, the molten salt steam-water power generation subsystem includes: a high-temperature molten salt tank, a high-temperature molten salt pump, a high-temperature bypass control valve, a high-temperature control valve, a high-temperature mixing control valve, a first molten salt-steam superheater, a first molten salt-steam-water evaporator, a molten salt-water preheater, a molten salt-steam reheater, a turbine high-pressure cylinder, a turbine medium and low-pressure cylinders, a generator, a condenser, a condensate pump, a low-pressure heater, a deaerator, a storage power station feed pump, a first-level high-pressure heater, a second-level high-pressure heater and a control valve 55.

[0119] Molten salt side: the high-temperature molten salt pump outlet is connected to the first molten salt-steam superheater through a high-temperature control valve, and is connected to the molten salt steam reheater through a high-temperature mixing control valve. The outlet of the first molten salt-steam superheater is connected to the inlet of the first molten salt-steam-water evaporator through a first series control valve, the outlet of the first molten salt-steam-water evaporator is connected to the inlet of the molten salt-water preheater through a second series control valve, the outlet of the molten salt-water preheater is connected to the low-temperature molten salt tank, and the outlet of the molten salt-steam reheater is connected to the inlet of the second molten salt-steam-water evaporator.

[0120] Steam side: The condensate is connected to the low-pressure heater, deaerator, energy storage power station feed water pump, level 1 high-pressure heater, and level 2 high-pressure heater in sequence through the condensate pump. The heated feed water is sent to the molten salt-water preheater inlet through the control valve 55. The molten salt-water preheater outlet is connected to the molten salt-steam-water evaporator inlet, the molten salt-steam-water evaporator outlet is connected to the molten salt-steam superheater inlet, the molten salt steam superheater outlet is connected to the steam inlet of the turbine high-pressure cylinder, the turbine high-pressure cylinder outlet is connected to the molten salt-steam reheater, and the molten salt-steam reheater outlet is connected to the steam inlet of the turbine intermediate-pressure cylinder.

[0121] Specifically, the high-temperature molten salt stored in the high-temperature molten salt tank is driven by the molten salt pump. A part of the high-temperature molten salt flows through the first molten salt-steam superheater, the first molten salt-steam-water evaporator, and the molten salt-water preheater to heat the feed water from the high-pressure heater of the steam turbine. The generated steam is sent to the high-pressure cylinder of the steam turbine to generate power. The other part flows through the molten salt-steam reheater to heat the exhaust steam from the high-pressure cylinder of the steam turbine. The generated reheated steam is sent to the medium-pressure cylinder of the steam turbine to generate power. The feed water from the condenser flows through the low-pressure heater, the deaerator, and the high-pressure heater under the action of the condensate pump. The heated feed water is sent to the molten salt-water preheater for heat exchange.

[0122] The superheated steam generated by the countercurrent heat exchange between the molten salt and the feed water is sent to the steam inlet of the high-pressure cylinder 12 of the steam turbine to generate power, and the exhaust steam of the high-pressure cylinder 12 of the steam turbine enters the molten salt-steam reheater 10 for heating and then is sent to the medium and low-pressure cylinders 13 of the steam turbine to generate power. The thermal power of the molten salt-steam reheater can be controlled by the high-temperature mixing control valve to improve the power generation efficiency and economy.

[0123] It can be seen from the above technical scheme that the combined heat and power system based on molten salt heat storage heats the feed water through high-temperature molten salt to generate superheated steam, which is sent to the steam turbine to generate power, thereby shifting the time-consuming use of abandoned electricity from renewable energy and improving the peak regulation rate of the power grid.

[0124] In this embodiment, the cogeneration operation mode is triggered by the simultaneous operation of the power supply operation mode and the heating operation mode. Figure 8 This is a schematic diagram of a combined heat and power operation mode adopted in the embodiment of the present application. The specific structure of the combined heat and power subsystem can refer to the above embodiment.

[0125] like Figure 8 As shown in the figure, the power generation operation principle in the combined heat and power operation mode:

[0126] The high-temperature molten salt stored in the high-temperature molten salt tank is driven by the molten salt pump. The first route flows through the first molten salt-steam superheater, the first molten salt-steam evaporator, and the molten salt-water preheater through the high-temperature control valve to heat the feed water from the high-pressure heater of the steam turbine, and the generated steam is sent to the high-pressure cylinder of the steam turbine to generate power. In the first route, the first molten salt-steam superheater is connected to the first molten salt-steam evaporator through the first series control valve, and the first molten salt-steam evaporator is connected to the molten salt-water preheater through the second series control valve. In addition, the outlet end of the first molten salt-steam superheater is connected to the molten salt mixer through the first residual temperature mixing control valve, and the outlet end of the first molten salt-steam evaporator is connected to the molten salt mixer through the second residual temperature mixing control valve. The second route flows through the molten salt-steam reheater through the high-temperature mixing control valve to heat the exhaust steam from the high-pressure cylinder of the steam turbine, and the generated reheated steam is sent to the intermediate-pressure cylinder of the steam turbine to generate power. The feed water from the condenser flows through the low-pressure heater, deaerator, and high-pressure heater under the action of the condensate pump. The heated feed water is sent to the molten salt-water preheater for heat exchange. The superheated steam generated by the countercurrent heat exchange between the molten salt and the feed water is sent to the steam inlet of the high-pressure cylinder 12 of the steam turbine for power generation. The exhaust steam of the high-pressure cylinder 12 of the steam turbine enters the molten salt-steam reheater 10 for heating and is sent to the medium and low-pressure cylinders 13 of the steam turbine for power generation. The third route flows into the molten salt mixer through the high-temperature mixing control valve.

[0127] like Figure 8 As shown in the figure, the heating operation principle in the combined heat and power operation mode:

[0128] When the target temperature of the molten salt in the heating condition is not equal to the medium-temperature molten salt, the amount of molten salt flowing through each control valve is adjusted by controlling the opening (0-100 degrees) of the low-temperature mixing control valve, the high-temperature mixing control valve, the high-temperature mixing control valve, the medium-temperature mixing control valve, the first residual temperature mixing control valve, and the second residual temperature mixing control valve, so as to achieve at least two of the following:

[0129] The low-temperature molten salt in the low-temperature molten salt tank is driven by the low-temperature molten salt pump and sent to the molten salt mixer through the low-temperature mixing control valve;

[0130] The high-temperature molten salt in the high-temperature molten salt tank is driven by the high-temperature molten salt pump and sent to the molten salt mixer through the high-temperature mixing control valve;

[0131] The medium-temperature molten salt in the medium-temperature molten salt tank is driven by the medium-temperature molten salt pump and sent to the molten salt mixer through the medium-temperature mixing control valve;

[0132] The first residual temperature molten salt outputted by the first molten salt-steam superheater is sent to the molten salt mixer via the first residual temperature mixing control valve;

[0133] The second residual temperature molten salt outputted from the first molten salt-steam-water evaporator is delivered to the molten salt mixer via the second residual temperature mixing control valve.

[0134] Furthermore, after the molten salt mixer mixes the above two molten salts of different temperatures, the mixed molten salt is sent to the second molten salt-steam superheater and the second molten salt-steam-water evaporator in sequence, and the molten salt after heat release returns to the low-temperature molten salt tank.

[0135] It should be noted that the actual temperature of the mixed molten salt can be detected by a temperature sensor at the outlet of the molten salt mixer, and each control valve can be dynamically adjusted according to the actual temperature and the target temperature.

[0136] For example, if the target temperature is lower than the first preset temperature (temperature of high-temperature molten salt) and higher than the third preset temperature (temperature of medium-temperature molten salt), and higher than the temperature of the first residual-temperature molten salt, the high-temperature mixing control valve is controlled to the first opening, the medium-temperature control valve is opened to the second opening, and the other control valves are closed. The high-temperature molten salt in the high-temperature molten salt tank is driven by the high-temperature molten salt pump and sent to the molten salt mixer through the high-temperature mixing control valve; the medium-temperature molten salt in the medium-temperature molten salt tank is driven by the medium-temperature molten salt pump and sent to the molten salt mixer through the medium-temperature mixing control valve. After the molten salt mixer mixes the medium-temperature molten salt and the high-temperature molten salt, the mixed molten salt is sent to the second molten salt-steam superheater and the second molten salt-steam-water evaporator in sequence, and the molten salt after heat release returns to the low-temperature molten salt tank. Alternatively, the high-temperature mixing control valve is controlled to the third opening, the low-temperature control valve is opened to the fourth opening, and the other control valves are closed. The high-temperature molten salt in the high-temperature molten salt tank is driven by the high-temperature molten salt pump and sent to the molten salt mixer through the high-temperature mixing control valve, and the low-temperature molten salt in the low-temperature molten salt tank is driven by the low-temperature molten salt pump and sent to the molten salt mixer through the low-temperature mixing control valve. After the molten salt mixer mixes the low-temperature molten salt and the high-temperature molten salt, the mixed molten salt is sequentially sent to the second molten salt-steam superheater and the second molten salt-steam evaporator, and the molten salt after heat release returns to the low-temperature molten salt tank.

[0137] It should be noted that the first opening degree, the second opening degree, the third opening degree, and the fourth opening degree are all calculated by the difference between the actual temperature and the target temperature.

[0138] It should be noted that when the target temperature is equal to one of the first preset temperature, the second preset temperature, the first residual temperature, and the second residual temperature, the corresponding mixing control valve is opened and the other mixing control valves are closed without mixing.

[0139] It should be noted that, in the cogeneration operation mode, the feed water of the molten salt heating system can be drawn from the second-stage high-pressure heater 29 and sent to the feed water pump 45 through the control valve 44. The feed water temperature in this working condition is relatively high, and there is no need to start the feed water electric heater. The feed water sent to the molten salt heating system forms a closed loop in the system, and a large amount of feed water is required only at the first startup. No water is required subsequently or only the leakage of the system operation is supplemented.

[0140] In the cogeneration operation mode, the water supply sources include: one 2-stage high-pressure heater outlet is divided into two paths, one is sent to the molten salt-water preheater 7 through the control valve 55, and the other is sent to the inlet of the molten salt heating steam pipeline water supply pump 45 through the control valve 56. At this time, the water temperature meets the requirements and the water supply electric heater 46 does not need to be turned on.

[0141] It can be seen from the above technical scheme that the flexible combined heat and power system based on molten salt heat storage provided by the embodiment of the present application, in the combined heat and power operation mode, uses the thermal energy stored in high-temperature molten salt for peak-shaving power generation, and when it is necessary to mix molten salt, by controlling the opening of the low-temperature mixing control valve, the high-temperature mixing control valve, the high-temperature mixing control valve, the medium-temperature mixing control valve, the first residual temperature mixing control valve, and the second residual temperature mixing control valve, the amount of molten salt flowing through each control valve is adjusted respectively, so that at least two molten salts of different temperatures enter the molten salt mixer, and the above two molten salts of different temperatures are mixed by the molten salt mixer, and the mixed molten salt is sent to the second molten salt-steam superheater and the second molten salt-steam evaporator in sequence, and the molten salt after heat release returns to the low-temperature molten salt tank. Therefore, this scheme can perform combined heat and power, and can use the residual temperature molten salt in the power generation process for mixing to obtain molten salt for heating, which improves the heating efficiency and the utilization rate of the heat of the high-temperature molten salt. Further, through the target temperature, the control of each mixing control valve is realized to improve the flexibility of heating.

[0142] In summary, this solution has at least the following beneficial effects:

[0143] Compared with the molten salt heat storage system coupled with coal-fired power generation, this system realizes the complete decoupling of the energy storage system and the traditional coal-fired power plant. The energy storage system constitutes an independent power station, including three parts: heat storage system, power generation system and heating system. It can carry out large-scale and long-term energy storage, and the charging and discharging processes have higher flexibility. The energy storage power station with cogeneration function has better efficiency and economy.

[0144] During the heat storage process of this system, the molten salt is heated to different temperature levels and stored in multiple tanks. According to the temperature matching principle, the molten salt in the high-temperature molten salt tank is used to heat the feed water to generate superheated steam, which is sent to the steam turbine to generate power.

[0145] This system can jointly operate the molten salt thermal storage power station power generation auxiliary power grid peak load operation mode (power generation operation mode) and the molten salt thermal storage system heating operation mode (heating operation mode). When the mixing time is reached, at least two molten salts of different temperatures are mixed, and the mixed molten salt is used to heat the heating system feed water. The generated steam is used to heat the heating circulating water for heating users. According to actual needs, the power generation system and the heating system can be operated jointly or separately, with convenient and simple control and high flexibility.

[0146] This system also has the functions of absorbing abandoned electricity from new energy power generation systems, assisting the grid in peak load regulation, and providing high temperature for circulating water of heat users. It can operate in the abandoned electricity heating molten salt heat storage mode (heat storage mode), the independent molten salt heat storage power station power generation assisting grid peak load regulation operation mode (power generation operation mode) and the molten salt heat storage system heating operation mode (heat supply operation mode). Each operation mode can be flexibly controlled according to needs, which can greatly reduce the abandoned electricity from new energy, assist the grid in peak load regulation, increase the proportion of new energy access to the grid, ensure regional heating needs, and reduce the dependence of heating on traditional coal-fired units.

[0147] The present application also provides an electronic device for implementing the control method. Fig. 9 As shown, Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application is provided, which shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiment of the present application. The electronic device in the embodiment of the present application may include but is not limited to fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Fig. 9 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0148] like Fig. 9 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 901, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 902 or a program loaded from a storage device 908 to a random access memory (RAM) 903. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 903. The processing device 901, the ROM 902, and the RAM 903 are connected to each other via a bus 904. An input / output (I / O) interface 905 is also connected to the bus 904.

[0149] Typically, the following devices may be connected to the I / O interface 905: an input device 906 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 907 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 908 including, for example, a memory card, a hard disk, etc.; and a communication device 909. The communication device 909 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Fig. 9 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0150] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any control method provided in the embodiment of the present application.

[0151] A computer-readable storage medium is also provided in an embodiment of the present application. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any control method provided in the embodiment of the present application.

[0152] It should also be noted that the device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the device embodiments provided by the present application, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines.

[0153] Through the description of the above implementation mode, the technicians in the field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present application, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0154] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0155] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, training device, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

Claims

1. A combined heat and power system based on molten salt heat storage, characterized in that: include: Thermal storage subsystem and combined heat and power subsystem; The heat storage subsystem includes a high-temperature molten salt tank for storing high-temperature molten salt and a low-temperature molten salt tank for storing low-temperature molten salt; the cogeneration subsystem includes a low-temperature blending control valve, a residual temperature blending control valve, a first heat exchange system, a second heat exchange system, and a molten salt mixer; wherein the first heat exchange system includes a multi-stage heat exchanger, and the second heat exchange system includes at least one stage of heat exchanger; The first heat exchange system is connected to the outlet of the high-temperature molten salt tank through the molten salt side inlet, connected to the inlet of the low-temperature molten salt tank through the molten salt side outlet, and connected to a preset power supply device through the steam-water side inlet and the steam-water side outlet; The molten salt side outlet of at least one target heat exchanger in the first heat exchange system is connected to the residual temperature inlet of the molten salt mixer through the residual temperature mixing control valve; the target heat exchanger is a heat exchanger other than the final stage heat exchanger in the first heat exchange system; the residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer; The outlet end of the low-temperature molten salt tank is connected to the low-temperature inlet end of the molten salt mixer through the low-temperature mixing control valve; the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer; The outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second heat exchange system, and is used to mix the molten salt input from the mixing inlet end and output the mixed molten salt, wherein the mixing inlet end includes a low-temperature inlet end and a residual temperature inlet end; The molten salt side outlet of the second heat exchange system is connected to the inlet of the low-temperature molten salt tank; the second heat exchange system is connected to a preset heating device through the steam-water side inlet and the steam-water side outlet.

2. The combined heat and power system based on molten salt heat storage according to claim 1 is characterized in that: The heat storage subsystem further includes a medium-temperature molten salt tank for storing medium-temperature molten salt, and the cogeneration subsystem further includes a medium-temperature mixing control valve; The mixing inlet also includes a medium-temperature inlet, and the outlet of the medium-temperature molten salt tank is connected to the medium-temperature inlet of the molten salt mixer through the medium-temperature mixing control valve, and the medium-temperature mixing control valve is used to control the amount of molten salt output from the medium-temperature molten salt tank to the molten salt mixer; The temperature of the low-temperature molten salt is a first preset temperature, the temperature of the high-temperature molten salt is a second preset temperature, and the temperature of the medium-temperature molten salt is a third preset temperature. The first preset temperature is lower than the third preset temperature and the third preset temperature is lower than the second preset temperature.

3. The combined heat and power system based on molten salt heat storage according to claim 1 is characterized in that: The thermal storage subsystem also includes a temperature sensor: The temperature sensor is arranged at the outlet end of the molten salt mixer, and is used to collect the actual temperature of the mixed molten salt output by the molten salt mixer.

4. The combined heat and power system based on molten salt heat storage according to claim 1 is characterized in that: The first heat exchange system includes a first molten salt-steam superheater, a first molten salt-steam-water evaporator and a molten salt-water preheater connected in series; the cogeneration subsystem also includes a first series control valve and a second series control valve, the residual temperature mixing control valve includes a first residual temperature mixing control valve and a second residual temperature mixing control valve, and the residual temperature inlet end of the molten salt mixer includes a first residual temperature inlet end and a second residual temperature inlet end; The molten salt side outlet end of the first molten salt-steam superheater is connected to the first residual temperature inlet end of the molten salt mixer through the first residual temperature mixing control valve, and is connected to the molten salt side inlet end of the first molten salt-steam evaporator through the first series control valve; The molten salt side outlet end of the first molten salt-steam-water evaporator is connected to the second residual temperature inlet end of the molten salt mixer through the second residual temperature mixing control valve, and is connected to the molten salt side inlet end of the molten salt-water preheater through the second series control valve.

5. The combined heat and power system based on molten salt heat storage according to claim 4 is characterized in that: The cogeneration subsystem further includes a high temperature control valve and a high temperature blending control valve, and the blending inlet end of the molten salt mixer further includes a high temperature inlet end; The outlet end of the high-temperature molten salt tank is connected to the molten salt side inlet end of the first molten salt-steam superheater through the high-temperature control valve, and is connected to the high-temperature inlet end of the molten salt mixer through the high-temperature mixing control valve.

6. The combined heat and power system based on molten salt heat storage according to any one of claim 5, characterized in that: The second heat exchange system comprises a second molten salt-steam superheater and a second molten salt-steam-water evaporator connected in series; The cogeneration subsystem further includes a first low-temperature molten salt pump and a first bypass control valve connected in parallel, a medium-temperature molten salt pump and a second bypass control valve connected in parallel, and a high-temperature molten salt pump and a third bypass control valve connected in parallel; The outlet end of the high-temperature molten salt tank is connected to the high-temperature control valve and the high-temperature mixing control valve respectively through the high-temperature molten salt pump; the outlet end of the low-temperature molten salt tank is connected to the low-temperature mixing control valve through the first low-temperature molten salt pump, and the outlet end of the medium-temperature molten salt tank is connected to the medium-temperature mixing control valve through the medium-temperature molten salt pump.

7. The combined heat and power system based on molten salt heat storage according to claim 2 is characterized in that: The thermal storage subsystem also includes: A low-temperature bypass control valve and a second low-temperature molten salt pump, a first-level electric heating control valve, a first-level electric heating molten salt heat exchanger, a medium-temperature inlet control valve, a second-level electric heating control valve, a second-level electric heating molten salt heat exchanger, a high-temperature inlet control valve, a first circuit switch, a transformer, a second circuit switch, and a third circuit switch 37 connected in parallel; The low-temperature molten salt tank is connected to the inlet end of the first-level electrically heated molten salt heat exchanger through the second low-temperature molten salt pump and the first-level electrically heated control valve in sequence, the outlet end of the first-level electrically heated molten salt heat exchanger is connected to the medium-temperature molten salt tank through the medium-temperature inlet control valve, and is connected to the inlet end of the second-level electrically heated molten salt heat exchanger through the second-level electrically heated control valve, and the outlet end of the second-level electrically heated molten salt heat exchanger is connected to the high-temperature molten salt tank through the high-temperature inlet control valve; The first-level electrically heated molten salt heat exchanger is connected to the secondary side of the transformer through the second circuit switch, the second-level electrically heated molten salt heat exchanger is connected to the secondary side of the transformer through the third circuit switch, and the primary side of the transformer is connected to the output end of the new energy power generation system through the first circuit switch.

8. A control method, characterized in that: include: In a preset cogeneration operation mode, based on a preset target temperature, the opening of a mixing control valve in a cogeneration system based on molten salt heat storage is controlled to adjust the amount of molten salt input to a molten salt mixer by the mixing control valve until the difference between the actual temperature of the mixed molten salt output by the molten salt mixer and the target temperature is lower than a preset temperature error threshold, wherein the mixing control valve includes a low-temperature mixing control valve and a residual-temperature mixing control valve; The combined heat and power system includes a heat storage subsystem and a combined heat and power subsystem, wherein the heat storage subsystem includes a high-temperature molten salt tank for storing high-temperature molten salt and a low-temperature molten salt tank for storing low-temperature molten salt; the combined heat and power subsystem includes a low-temperature blending control valve, a residual temperature blending control valve, a first heat exchange system, a second heat exchange system, and a molten salt mixer; wherein the first heat exchange system includes a multi-stage heat exchanger, and the second heat exchange system includes at least one stage of heat exchanger; The first heat exchange system is connected to the outlet of the high-temperature molten salt tank through the molten salt side inlet, connected to the inlet of the low-temperature molten salt tank through the molten salt side outlet, and connected to a preset power supply device through the steam-water side inlet and the steam-water side outlet; the molten salt side outlet of at least one target heat exchanger in the first heat exchange system is connected to the residual temperature inlet of the molten salt mixer through the residual temperature mixing control valve; the target heat exchanger is a heat exchanger other than the final heat exchanger in the first heat exchange system; the residual temperature mixing control valve is used to control the amount of molten salt output from the target heat exchanger to the molten salt mixer; the low-temperature molten salt tank The outlet end is connected to the low-temperature inlet end of the molten salt mixer through the low-temperature mixing control valve; the low-temperature mixing control valve is used to control the amount of molten salt output from the low-temperature molten salt tank to the molten salt mixer; the outlet end of the molten salt mixer is connected to the molten salt side inlet end of the second heat exchange system, which is used to mix the molten salt input from the mixing inlet end and output the mixed molten salt, and the mixing inlet end includes a low-temperature inlet end and a residual temperature inlet end; the molten salt side outlet end of the second heat exchange system is connected to the inlet end of the low-temperature molten salt tank; the second heat exchange system is connected to a preset heating device through a steam-water side inlet end and a steam-water side outlet end.

9. The control method according to claim 8, characterized in that: The heat storage subsystem further includes a medium-temperature molten salt tank for storing medium-temperature molten salt, and the cogeneration subsystem further includes a medium-temperature mixing control valve; The mixing inlet also includes a medium-temperature inlet, and the outlet of the medium-temperature molten salt tank is connected to the medium-temperature inlet of the molten salt mixer through the medium-temperature mixing control valve; the temperature of the low-temperature molten salt is a first preset temperature, the temperature of the high-temperature molten salt is a second preset temperature, and the temperature of the medium-temperature molten salt is a third preset temperature, the first preset temperature is lower than the third preset temperature, and the third preset temperature is lower than the second preset temperature; The mixing control valve also includes the medium-temperature mixing control valve.

10. The control method according to claim 8, characterized in that: The cogeneration subsystem further includes a high temperature control valve and a high temperature blending control valve, and the blending inlet end of the molten salt mixer further includes a high temperature inlet end; The outlet end of the high-temperature molten salt tank is connected to the first heat exchange system through the molten salt side inlet end through the high-temperature control valve, and is connected to the high-temperature inlet end of the molten salt mixer through the high-temperature mixing control valve; The admixture control valve further comprises the high temperature admixture control valve.

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