User-side photovoltaic photo-thermal fused salt energy storage cogeneration system

Abstract

The invention discloses a user-side photovoltaic photo-thermal fused salt energy storage combined heat and power system, and the system comprises a photovoltaic power generation module which is used for obtaining solar energy, converting the solar energy into electric energy, and transmitting the electric energy to a power user, a fused salt electric heating module and a power grid; the fused salt groove type light-gathering and heat-collecting module is used for focusing solar energy to heat a fused salt working medium and conveying the fused salt working medium to the fused salt energy storage module; the fused salt electric heating module is used for converting electric energy into heat energy to heat a fused salt working medium and transmitting the heated fused salt working medium to the fused salt energy storage module; the fused salt energy storage module is used for storing a fused salt working medium and obtaining heat energy stored in the fused salt working medium so as to transmit the heat energy to the steam generation module; and the steam generation module is used for generating different grades of steam by using the heat energy transmitted by the fused salt energy storage module, so that the various different grades of steam are used for power generation and heat supply. By means of the system, hot water, steam of different grades and electric energy can be provided for users at the same time, and the adaptive capacity to heat load changes is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic thermal energy and combined heat and power generation, and specifically relates to a user-side photovoltaic thermal energy storage combined heat and power generation system. Background Art

[0002] Solar energy and wind energy, as clean and renewable energy sources, are gradually becoming important forces in the transformation of the global energy structure. However, the discontinuity and large peak-to-valley differences of these two energy resources have also brought considerable challenges to the energy supply system. The supply of solar energy is affected by weather, sunshine hours and seasonal changes, while the generation of wind energy depends on the instability of wind speed and direction. This instability often leads to supply and demand contradictions between the energy supply side and the user side, especially when the peak of new energy power generation does not match the peak of electricity consumption, the problem is particularly prominent.

[0003] In order to effectively solve this problem, molten salt energy storage technology came into being and emerged in the energy field with its unique advantages. Molten salt energy storage technology realizes flexible scheduling and optimal allocation of energy by storing and releasing thermal energy. During the peak period of renewable energy power generation, excess electrical energy can be converted into thermal energy and stored in molten salt for emergency use. When electricity consumption is low or renewable energy power generation is insufficient, the thermal energy stored in the molten salt can be converted into electrical energy or thermal energy to meet the energy needs of users. This ability to shift peaks and fill valleys not only improves the utilization efficiency of energy equipment, but also effectively alleviates the contradiction between energy supply and demand, and promotes the consumption and large-scale development of new energy.

[0004] However, in remote areas or industrial parks where centralized heating / steam sources are difficult to cover, the existing combined heat and power system has a relatively simple heating mode and is not very adaptable to changes in heat load. This makes it difficult for the system to flexibly adjust and optimize configuration when facing different heat load demands.

[0005] Therefore, there is an urgent need to provide a user-side photovoltaic solar thermal molten salt energy storage cogeneration system that can provide users with hot water, steam of different grades and electricity at the same time, so as to enhance the adaptability of cogeneration to changes in heat load. Summary of the invention

[0006] The purpose of the present invention is to provide a user-side photovoltaic thermal molten salt energy storage cogeneration system to solve the above-mentioned problems existing in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a user-side photovoltaic, thermal, molten salt energy storage and heat and power cogeneration system, which comprises: a photovoltaic power generation module, a molten salt trough-type concentrating heat collection module, a molten salt electric heating module, a molten salt energy storage module and a steam generation module;

[0009] The photovoltaic power generation module is used to obtain solar energy, convert the solar energy into electrical energy, and transmit the converted electrical energy to the electricity user, the molten salt electric heating module and the power grid respectively;

[0010] The molten salt trough type concentrating heat collection module is used to focus solar energy to heat the molten salt working medium, and transport the heated molten salt working medium to the molten salt energy storage module;

[0011] A molten salt electric heating module, electrically connected to the photovoltaic power generation module, for converting the electric energy transmitted by the photovoltaic power generation module into thermal energy to heat the molten salt working fluid, and transmitting the heated molten salt working fluid to the molten salt energy storage module;

[0012] A molten salt energy storage module, used for storing molten salt working fluid and obtaining thermal energy stored in the molten salt working fluid to transfer the thermal energy to the steam generation module;

[0013] The steam generation module is used to generate steam of different grades using the heat energy transmitted by the molten salt energy storage module, so that the steam of various grades can be used to provide heat and generate electricity for heat users.

[0014] In one possible design, the photovoltaic power generation module includes: a photovoltaic component, an inverter and a power distribution device;

[0015] The photovoltaic module is used to obtain solar energy and convert it into electrical energy. The DC output end of the photovoltaic module is electrically connected to the DC input end of the inverter. The inverter converts the DC power transmitted by the photovoltaic module into AC power, and outputs the AC power to the AC input end of the power distribution equipment through the AC output end of the inverter.

[0016] The AC output end of the power distribution equipment is electrically connected to the electricity user, the molten salt electric heating module and the power grid respectively.

[0017] In a possible design, the molten salt trough type concentrating heat collection module includes: a parabolic reflector, a heat collection pipeline and a heat collection control unit;

[0018] The parabolic reflector is used to form a focusing trough to focus solar energy, and the heat collection pipeline is installed along the focal line of the parabolic reflector to provide a heating place and a transportation channel for the flowing molten salt working medium, so as to heat the molten salt and transport it to the molten salt energy storage module;

[0019] The heat collection control unit is used to obtain the solar azimuth and altitude angles and monitor the temperature of the molten salt working fluid, so as to adjust the angle of the parabolic reflector in real time according to the solar azimuth and altitude angles, and adjust the flow rate of the molten salt working fluid in the heat collection pipeline in real time according to the temperature of the molten salt working fluid.

[0020] In one possible design, the molten salt energy storage module includes: a high-temperature molten salt storage tank, a low-temperature molten salt storage tank, a salt mixing tank, a high-temperature molten salt pump, a low-temperature molten salt pump and a medium-temperature molten salt pump;

[0021] The input port of the high-temperature molten salt storage tank is connected to the molten salt trough-type solar collector module and the molten salt electric heating module through a pipeline, so as to collect and store the heated molten salt working medium, and the output port of the high-temperature molten salt storage tank transports the heated molten salt working medium to the steam generation system and the salt mixing tank respectively through the high-temperature molten salt pump;

[0022] The input port of the low-temperature molten salt storage tank is connected to the steam generation system through a pipeline, and is used to collect and store the molten salt working medium after heat release. The output port of the low-temperature molten salt storage tank transports the molten salt working medium after heat release to the molten salt trough type concentrating solar collector module and the molten salt electric heating module through the low-temperature molten salt pump;

[0023] The input port of the mixing salt tank is connected to the high-temperature molten salt storage tank and the steam generation system through a pipeline, and is used to mix molten salt working fluids of different temperatures to form a temperature-adjusting molten salt working fluid. The output port of the mixing salt tank transports the temperature-adjusting molten salt working fluid to the steam generation module through the medium-temperature molten salt pump, which is used to adjust the steam quality.

[0024] In one possible design, the steam generation module includes: a preheater, an evaporator and a superheater;

[0025] Among them, the high-temperature molten salt storage tank is connected to the working fluid input port of the superheater through a pipeline, the working fluid output port of the superheater transports the molten salt working fluid to the evaporator and the preheater in sequence through a pipeline, and the working fluid output port of the preheater is connected to the low-temperature molten salt storage tank and the mixing salt tank through a pipeline.

[0026] In a possible design, a steam turbine generator module and a heating module are also included;

[0027] Among them, the input port of the steam turbine generator module is connected with the steam generation module for obtaining the steam emitted by the steam generation module, the steam extraction pipeline of the steam turbine generator module is respectively connected with the heating module and the heat user, and the exhaust steam pipeline of the steam turbine generator module is respectively connected with the heating module and the heat user, so as to use the heat energy carried by the steam for heating and electrical energy conversion for the heat user.

[0028] In a possible design, the steam turbine generator module includes: an extraction back-pressure steam turbine generator and a condensing steam turbine generator;

[0029] Wherein: the steam input port of the extraction back-pressure steam turbine generator is connected to the steam generation module as the input port of the steam turbine generator module, and is used to obtain the steam emitted by the steam generation module for power generation; the extraction steam pipeline of the extraction back-pressure steam turbine generator is respectively connected to the heating module and the heat user; the exhaust steam pipeline of the extraction back-pressure steam turbine generator is respectively connected to the heating module, the heat user and the condensing steam turbine generator; and the steam output port of the extraction back-pressure steam turbine generator is connected to the steam input port of the condensing steam turbine generator;

[0030] The condensing steam turbine generator is used to obtain steam and exhaust steam output by the extraction back-pressure steam turbine generator to generate electricity.

[0031] In one possible design, the heating module includes: a steam-water heat exchanger and a water-water heat exchanger;

[0032] Among them, the water-to-water heat exchanger is used to receive the return water of the heat user and perform primary heat exchange, and the steam-to-water heat exchanger is used to receive the return water of the heat user after the primary heat exchange and perform secondary heat exchange to heat the return water of the heat user to a preset heating temperature.

[0033] In a possible design, a main control module is also included;

[0034] Among them, the main control module is used to obtain the electricity demand of the electricity user and the heating demand of the heat user, and the main control module is electrically connected to the photovoltaic power generation module, the molten salt trough concentrating solar collector module, the molten salt electric heating module, the molten salt energy storage module and the steam generation module, respectively, to coordinate the operation of each module, and according to the electricity demand of the electricity user and the heating demand of the heat user, to control the photovoltaic power generation module and the steam generation module to emit electricity and steam accordingly.

[0035] In a possible design, the main control module is also electrically connected to the power grid, and is used to input valley electricity from the power grid into the molten salt electric heating module, so as to convert the electrical energy transmitted by the power grid into thermal energy.

[0036] Beneficial effect: The present invention provides a user-side photovoltaic-thermal-molten-salt-energy-storage-heat-and-power combined heat and power system, which comprises: a photovoltaic power generation module, a molten-salt trough-type concentrating-heat-collecting module, a molten-salt-electric heating module, a molten-salt-energy-storage module and a steam generation module; wherein the photovoltaic power generation module is used to obtain solar energy to convert solar energy into electric energy, and transmit the converted electric energy to the electric user, the molten-salt-electric heating module and the power grid respectively; the molten-salt trough-type concentrating-heat-collecting module is used to focus solar energy to heat the molten-salt working medium, and transport the heated molten-salt working medium to the molten-salt-electric heating module; The molten salt energy storage module; the molten salt electric heating module is electrically connected to the photovoltaic power generation module and is used to convert the electric energy transmitted by the photovoltaic power generation module into thermal energy to heat the molten salt working fluid, and transmit the heated molten salt working fluid to the molten salt energy storage module; the molten salt energy storage module is used to store the molten salt working fluid and obtain the stored thermal energy in the molten salt working fluid to transmit the thermal energy to the steam generation module; the steam generation module is used to generate steam of different grades using the thermal energy transmitted by the molten salt energy storage module, so as to use the steam of different grades to provide heat and generate electricity for heat users. Through this system, hot water, steam of different grades and electric energy can be provided to users at the same time, so as to enhance the adaptability of the cogeneration system to changes in heat load. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a functional structure diagram of a user-side photovoltaic thermal molten salt energy storage cogeneration system in Example 1 of the present invention;

[0038] Figure 2 This is a connection diagram of a user-side photovoltaic thermal molten salt energy storage cogeneration system in Example 2 of the present invention.

[0039] In the figure: 1. Photovoltaic power generation module; 2. Molten salt trough type concentrating solar collector module; 3. High-temperature molten salt storage tank; 4. High-temperature molten salt pump; 5. Low-temperature molten salt storage tank; 6. Low-temperature molten salt pump; 7. Mixing salt tank; 8. Medium-temperature molten salt pump; 9. Steam generation module; 10. Extraction back pressure steam turbine generator; 11. Condensing steam turbine generator; 12. Condenser; 13. Condensate tank; 14. Condensate pump: 15. Low-pressure heater; 16. Deaerator; 17. Feed water pump; 18. High-pressure heater; 19. Steam-water heat exchanger; 20. Water-water heat exchanger; 21. Heat user; 22. Electricity user; 23. Distribution cabinet; 24. Molten salt electric heating module; 25. Power grid; 26. Molten salt energy storage module. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0041] It should be understood that although the terms first, second, etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another unit. For example, a first unit can be referred to as a second unit, and similarly, a second unit can be referred to as a first unit without departing from the scope of the exemplary embodiments of the present invention.

[0042] It should be understood that the term "and / or" that may appear in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" that may appear in this article describes another type of association object relationship, indicating that two relationships may exist. For example, A / and B can represent two situations: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0043] Embodiment 1:

[0044] like Figure 1 As shown, this embodiment provides a user-side photovoltaic thermal molten salt energy storage cogeneration system, which includes: a photovoltaic power generation module 1, a molten salt trough concentrating heat collection module 2, a molten salt electric heating module 24, a molten salt energy storage module 26 and a steam generation module 9;

[0045] The photovoltaic power generation module 1 is used to obtain solar energy to convert the solar energy into electrical energy, and transmit the converted electrical energy to the electricity user 22, the molten salt electric heating module 24 and the power grid 25 respectively;

[0046] The molten salt trough type concentrating heat collecting module 2 is used to focus solar energy to heat the molten salt working medium, and transport the heated molten salt working medium to the molten salt energy storage module 26;

[0047] The molten salt electric heating module 24 is electrically connected to the photovoltaic power generation module 1 and is used to convert the electric energy transmitted by the photovoltaic power generation module 1 into thermal energy to heat the molten salt working medium, and transmit the heated molten salt working medium to the molten salt energy storage module 26;

[0048] The molten salt energy storage module 26 is used to store the molten salt working medium and obtain the thermal energy stored in the molten salt working medium to transfer the thermal energy to the steam generation module 9;

[0049] The steam generation module 9 is used to generate steam of different grades using the heat energy transmitted by the molten salt energy storage module 26, so that the steam of various grades can be used to provide heat and generate electricity for the heat user 21.

[0050] The molten salt working fluid is preferably a ternary molten salt, which is a mixed salt of 7% NaNO3+53% KNO3+40% NaNO2. The ternary molten salt has good thermal stability at 450°C and its operating temperature range is 180°C-450°C.

[0051] It should be noted that the photovoltaic power generation module 1 is used to obtain solar energy to convert solar energy into electrical energy, and transmit the converted electrical energy to the electricity user 22, the molten salt electric heating module 24 and the power grid 25 respectively; the electrical energy transmission here will be carried out in a hierarchical manner in actual implementation. First, the electrical energy generated by the photovoltaic power generation module 1 will be supplied to the electricity user 22 for use according to the electricity demand of the electricity user 22. After meeting the use of the electricity user 22, if there is surplus electrical energy, it can be transmitted to the molten salt electric heating module 24 for heating the molten salt working fluid and completing energy storage. After that, if there is still surplus electrical energy, it can be transmitted to the power grid 25 to complete the power access to the grid.

[0052] The molten salt energy storage module 26 is used to store the molten salt working medium and obtain the stored heat energy in the molten salt working medium to transfer the heat energy to the steam generation module 9; and the steam generation module 9 is used to generate steam of different grades, so that the steam of various grades can be used to provide heat and generate electricity for the heat user 21. The steam of different grades generated by the steam generation module 9 can be operated under different working conditions when the demand of the heat user 21 is different, so as to meet the different needs of the heat user 21.

[0053] Through the setting of this cogeneration system, especially in areas with good solar energy resources and insufficient heating in surrounding areas, when users in the area have a wide range of heat load demands, this system can simultaneously provide users with hot water, steam of different grades and electricity, realize cogeneration, and enhance the system's adaptability to changes in users' heat load demands.

[0054] Embodiment 2:

[0055] like Figure 2 As shown, this embodiment provides a user-side photovoltaic solar thermal molten salt energy storage cogeneration system. In a possible implementation, the photovoltaic power generation module 1 includes: a photovoltaic component, an inverter and a power distribution device;

[0056] The photovoltaic module is used to obtain solar energy and convert it into electrical energy. The DC output end of the photovoltaic module is electrically connected to the DC input end of the inverter. The inverter converts the DC power transmitted by the photovoltaic module into AC power, and outputs the AC power to the AC input end of the power distribution equipment through the AC output end of the inverter.

[0057] The AC output end of the power distribution equipment is electrically connected to the power user 22 , the molten salt electric heating module 24 and the power grid 25 through the power distribution cabinet 23 .

[0058] In a possible implementation, the molten salt trough type concentrating heat collection module 2 includes: a parabolic reflector, a heat collection pipeline and a heat collection control unit;

[0059] The parabolic reflector is used to form a focusing trough to focus solar energy, and the heat collecting pipeline is installed along the focal line of the parabolic reflector to provide a heating place and a transportation channel for the flowing molten salt working medium, so as to heat the molten salt and transport it to the molten salt energy storage module 26;

[0060] The heat collection control unit is used to obtain the solar azimuth and altitude angles and monitor the temperature of the molten salt working fluid, so as to adjust the angle of the parabolic reflector in real time according to the solar azimuth and altitude angles, and adjust the flow rate of the molten salt working fluid in the heat collection pipeline in real time according to the temperature of the molten salt working fluid.

[0061] It should be noted that, in the specific implementation, the heat collection control unit is also regulated by the main control module, but is only used for the internal control of the molten salt trough type concentrating heat collection module 2. Its calculation amount is small and does not require too much intervention from the main control module. The heat collection control unit can obtain the solar azimuth and altitude angle in real time through an external photosensitive sensor, and according to the feedback signal of the photosensitive sensor, control the stepper motor or hydraulic drive device to adjust the pitch angle and horizontal rotation angle of the focusing trough to ensure accurate tracking of the solar trajectory (single-axis or dual-axis tracking) all day long; the heat collection control unit also monitors the temperature of the molten salt working fluid through temperature sensors installed at the inlet and outlet of the heat collection pipeline, and adjusts each molten salt pump (such as the flow rate of the low-temperature molten salt pump 6) according to the feedback temperature signal to match the photothermal input power and avoid overheating or heat loss.

[0062] In a possible implementation, the molten salt energy storage module 26 includes: a high-temperature molten salt storage tank 3, a low-temperature molten salt storage tank 5, a salt mixing tank 7, a high-temperature molten salt pump 4, a low-temperature molten salt pump 6 and a medium-temperature molten salt pump 8;

[0063] The input port of the high-temperature molten salt storage tank 3 is connected to the molten salt trough-type solar collector module 2 and the molten salt electric heating module 24 through a pipeline, so as to collect and store the heated molten salt working medium, and the output port of the high-temperature molten salt storage tank 3 transports the heated molten salt working medium to the steam generation system and the mixed salt tank 7 respectively through the high-temperature molten salt pump 4;

[0064] The input port of the low-temperature molten salt storage tank 5 is connected to the steam generation system through a pipeline, and is used to collect and store the molten salt working medium after exothermicity. The output port of the low-temperature molten salt storage tank 5 transports the molten salt working medium after exothermicity to the molten salt trough type concentrating solar collector module 2 and the molten salt electric heating module 24 through the low-temperature molten salt pump 6;

[0065] The input port of the mixing salt tank 7 is connected to the high-temperature molten salt storage tank 3 and the steam generation system through a pipeline, and is used to mix molten salt working fluids of different temperatures to form a temperature-adjusting molten salt working fluid. The output port of the mixing salt tank 7 transports the temperature-adjusting molten salt working fluid to the steam generation module 9 through the medium-temperature molten salt pump 8, which is used to adjust the steam quality.

[0066] Among them, the heat collection pipeline of the molten salt trough type concentrating solar collector module 2 is connected in parallel with the molten salt electric heating module 24 to the outlet of the low-temperature molten salt pump 6. After the two molten salts absorb heat, they merge into the high-temperature molten salt storage tank 3. Therefore, in the heating stage of the molten salt working fluid, the heating paths are correspondingly divided into two, namely photothermal heating and electric heating: and in the heat release stage of the molten salt working fluid, there are two steam mode working conditions: high-temperature steam mode and medium-temperature steam mode.

[0067] It should be noted that in the specific implementation, the molten salt energy storage module 26 also includes matching pipelines and some key valves, specifically: including high-temperature molten salt pipelines, low-temperature molten salt pipelines and mixing salt tank 7 pipelines, etc., wherein the high-temperature molten salt pipeline adopts high-temperature resistant materials (for example: stainless steel and ceramic lining), connecting the high-temperature storage tank 3 to the steam generating module 9 and the mixing salt tank 7, wherein a high-temperature regulating valve is required to control the flow of the high-temperature molten salt working fluid, and a one-way valve is provided to prevent the molten salt working fluid from backflowing; and the low-temperature molten salt pipeline connects the low-temperature storage tank 5 to the molten salt trough type concentrating solar collector module 2 and the molten salt electric heating module 24, therefore, it is necessary to set a diverter valve at the outlet of the low-temperature molten salt pipeline for dynamically allocating the photothermal and electric heating paths; the mixing salt tank 7 pipeline needs to be provided with a three-way valve and a proportional regulating valve for accurately controlling the mixing ratio of the high-temperature and low-temperature molten salt working fluids, so as to facilitate the regulation of the temperature of the molten salt working fluid.

[0068] In a possible implementation, the steam generation module 9 includes: a preheater, an evaporator and a superheater;

[0069] Among them, the high-temperature molten salt storage tank 3 is connected to the working fluid input port of the superheater through a pipeline, and the working fluid output port of the superheater transports the molten salt working fluid to the evaporator and the preheater in sequence through a pipeline, and the working fluid output port of the preheater is connected to the low-temperature molten salt storage tank 5 and the mixing salt tank 7 through a pipeline.

[0070] It should be noted that in the steam generation module 9, the low-temperature feed water comes from the condensate tank 13, and after being pressurized by the feed water pump 17, it first enters the preheater from the preheater inlet. The preheated water enters the evaporator to absorb the heat of the molten salt working medium and is converted into saturated steam. Then the saturated steam is transported from the evaporator outlet to the superheater, and further absorbs the molten salt heat energy to become high-temperature superheated steam. In contrast to the feed water direction, the high-temperature molten salt working medium (450°C) enters the superheater from the high-temperature storage tank 3, and the temperature drops (to about 400°C) after releasing heat. The cooled molten salt working medium flows into the evaporator to heat the water to saturated steam (the molten salt temperature also drops to about 300°C accordingly). After that, the remaining molten salt working medium enters the preheater to preheat the feed water to near the boiling point (the final temperature of the molten salt drops to 180°C-200°C). Finally, the cooled low-temperature molten salt working medium returns from the preheater outlet to the low-temperature storage tank 5 or the mixed salt tank 7 to complete the heat release cycle.

[0071] In a possible implementation, it also includes a steam turbine generator module and a heating module;

[0072] Among them, the input port of the steam turbine generator module is connected with the steam generating module 9 for obtaining the steam emitted by the steam generating module 9, the steam extraction pipeline of the steam turbine generator module is respectively connected with the heating module and the heat user 21, and the exhaust steam pipeline of the steam turbine generator module is respectively connected with the heating module and the heat user 21, so as to use the heat energy carried by the steam for heating and electrical energy conversion for the heat user 21.

[0073] It should be noted that when the salt mixing tank 7 is not working, the steam generating module 9 can directly generate high-temperature steam (450°C) for use by the extraction back-pressure steam turbine generator 10; when the salt mixing tank 7 is working, the steam generating module 9 can generate medium-temperature steam (250°C-400°C) for use by the condensing steam turbine generator 11 and the heating module.

[0074] In a possible implementation, the steam turbine generator module includes: an extraction back-pressure steam turbine generator 10 and a condensing steam turbine generator 11;

[0075] Wherein: the steam input port of the extraction back-pressure steam turbine generator 10 is connected to the steam generation module 9 as the input port of the steam turbine generator module, and is used to obtain the steam emitted by the steam generation module 9 for power generation, the extraction steam pipeline of the extraction back-pressure steam turbine generator 10 is respectively connected to the heating module and the heat user 21, the exhaust steam pipeline of the extraction back-pressure steam turbine generator 10 is respectively connected to the heating module, the heat user 21 and the condensing steam turbine generator 11, and the steam output port of the extraction back-pressure steam turbine generator 10 is connected to the steam input port of the condensing steam turbine generator 11;

[0076] The condensing steam turbine generator 11 is used to obtain steam and exhaust steam output by the extraction back-pressure steam turbine generator 10 to generate electricity.

[0077] It should be noted that the steam turbine generator module adopts the method of "determining electricity by heat". Under the heating condition, the heat load demand is used as the adjustment object. After the heating demand of the heat user 21 is met, the remaining steam is used to generate electricity. In actual implementation, the steam turbine generator module includes an extraction back-pressure steam turbine generator 10, a condensing steam turbine generator 11 and a conventional condenser 12, a condensate tank 13, a condensate pump 14, a low-pressure heater 15, a deaerator 16, a feed water pump 17, a high-pressure heater 18, etc. The high-temperature steam from the steam generating module 9 first passes through an extraction back-pressure steam turbine to generate electricity. The extraction steam pipeline is connected to the steam-water heat exchanger 19 of the heating system and the heat user 21. The exhaust steam pipeline of the extraction back-pressure steam turbine generator 10 is divided into three routes, one of which is connected to the steam-water heat exchanger 19 of the heating system, one of which is transported to the heat user 21 to meet its steam demand, and one of which is transported to the condensing steam turbine generator 11 to generate electricity. The exhaust steam of the condensing steam turbine generator 11 passes through the condenser 12 and is connected to the condensate tank 13.

[0078] In a possible implementation, the heating module includes: a steam-water heat exchanger 19 and a water-water heat exchanger 20;

[0079] Among them, the water-to-water heat exchanger 20 is used to receive the return water of the heat user 21 and perform primary heat exchange, and the steam-to-water heat exchanger 19 is used to receive the return water of the heat user 21 after the primary heat exchange and perform secondary heat exchange to heat the return water of the heat user 21 to a preset heating temperature.

[0080] Among them, the steam-water heat exchanger 19 and the water-water heat exchanger 20 are used to realize two-stage heat exchange. The return water of the heat user 21 is generally 50°C and flows through the water-water heat exchanger 20 and the steam-water heat exchanger 19 in turn to absorb heat in two stages to reach the design temperature of generally 110°C before being supplied to the heat user 21 for use.

[0081] In a possible implementation, it further includes a main control module;

[0082] Among them, the main control module is used to obtain the electricity demand of the electricity user 22 and the heating demand of the heat user 21, and the main control module is electrically connected to the photovoltaic power generation module 1, the molten salt trough concentrating collector module 2, the molten salt electric heating module 24, the molten salt energy storage module 26 and the steam generation module 9, respectively, to coordinate the operation of each module, and according to the electricity demand of the electricity user 22 and the heating demand of the heat user 21, to control the photovoltaic power generation module 1 and the steam generation module 9 to emit electricity and steam accordingly.

[0083] In a possible implementation, the main control module is also electrically connected to the power grid 25, and is used to input valley electricity of the power grid 25 into the molten salt electric heating module 24, so as to convert the electric energy transmitted by the power grid 25 into thermal energy.

[0084] The cogeneration system in this embodiment can dynamically switch between four operating modes according to the heat load demand under the control of the main control module:

[0085] When the heat load is at its maximum, the salt mixing tank 7 is activated to generate medium-temperature steam, giving priority to meeting the heating and user needs;

[0086] At medium heat load, high-temperature steam is directly generated to drive the extraction back-pressure steam turbine generator 10 to generate electricity;

[0087] When the heat load is low, the steam extraction volume is reduced and all the exhaust steam is used for power generation;

[0088] When there is no heat load, all the high-temperature steam enters the condensing steam turbine generator 11 to generate electricity.

[0089] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A user-side photovoltaic thermal molten salt energy storage combined heat and power system, It is characterized in that It comprises: a photovoltaic power generation module (1), a molten salt trough-type light-collecting and heat-collecting module (2), a molten salt electric heating module (24), a molten salt energy storage module (26) and a steam generation module (9); The photovoltaic power generation module (1) is used to obtain solar energy, convert the solar energy into electrical energy, and transmit the converted electrical energy to the electricity user (22), the molten salt electric heating module (24) and the power grid (25) respectively; A molten salt trough-type concentrating heat collection module (2) is used to focus solar energy to heat a molten salt working medium, and to transport the heated molten salt working medium to the molten salt energy storage module (26); A molten salt electric heating module (24), electrically connected to the photovoltaic power generation module (1), used for converting the electric energy transmitted by the photovoltaic power generation module (1) into thermal energy to heat the molten salt working fluid, and transmitting the heated molten salt working fluid to the molten salt energy storage module (26); A molten salt energy storage module (26) is used to store molten salt working fluid and obtain thermal energy stored in the molten salt working fluid so as to transfer the thermal energy to the steam generating module (9); The steam generation module (9) is used to generate steam of different qualities using the heat energy transmitted by the molten salt energy storage module (26), so that the steam of different qualities can be used to provide heat and generate electricity for the heat user (21).

2. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 1 is characterized in that: The photovoltaic power generation module (1) comprises: a photovoltaic component, an inverter and a power distribution device; The photovoltaic module is used to obtain solar energy and convert it into electrical energy. The DC output end of the photovoltaic module is electrically connected to the DC input end of the inverter. The inverter converts the DC power transmitted by the photovoltaic module into AC power, and outputs the AC power to the AC input end of the power distribution equipment through the AC output end of the inverter. The AC output end of the power distribution equipment is electrically connected to the power user (22), the molten salt electric heating module (24) and the power grid (25) respectively.

3. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 1 is characterized in that: The molten salt trough type light-collecting and heat-collecting module (2) comprises: a parabolic reflector, a heat-collecting pipeline and a heat-collecting control unit; The parabolic reflector is used to form a focusing trough to focus solar energy, and the heat collection pipeline is installed along the focal line of the parabolic reflector to provide a heating place and a transportation channel for the flowing molten salt working medium, so as to heat the molten salt and transport it to the molten salt energy storage module (26); The heat collection control unit is used to obtain the solar azimuth and altitude angles and monitor the temperature of the molten salt working fluid, so as to adjust the angle of the parabolic reflector in real time according to the solar azimuth and altitude angles, and adjust the flow rate of the molten salt working fluid in the heat collection pipeline in real time according to the temperature of the molten salt working fluid.

4. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 1 is characterized in that: The molten salt energy storage module (26) comprises: a high-temperature molten salt storage tank (3), a low-temperature molten salt storage tank (5), a salt mixing tank (7), a high-temperature molten salt pump (4), a low-temperature molten salt pump (6) and a medium-temperature molten salt pump (8); The input port of the high-temperature molten salt storage tank (3) is connected to the molten salt trough-type solar-concentrating collector module (2) and the molten salt electric heating module (24) through a pipeline, and is used to collect and store the heated molten salt working medium. The output port of the high-temperature molten salt storage tank (3) transports the heated molten salt working medium to the steam generation system and the salt mixing tank (7) respectively through the high-temperature molten salt pump (4); The input port of the low-temperature molten salt storage tank (5) is connected to the steam generation system via a pipeline, and is used to collect and store the molten salt working medium after heat release, and the output port of the low-temperature molten salt storage tank (5) transports the molten salt working medium after heat release to the molten salt trough-type concentrating solar collector module (2) and the molten salt electric heating module (24) via the low-temperature molten salt pump (6); The input port of the salt mixing tank (7) is connected to the high-temperature molten salt storage tank (3) and the steam generation system through a pipeline, and is used to mix molten salt working fluids of different temperatures to form a temperature-adjusting molten salt working fluid. The output port of the salt mixing tank (7) transports the temperature-adjusting molten salt working fluid to the steam generation module (9) through the medium-temperature molten salt pump (8) for adjusting the steam quality.

5. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 4 is characterized in that: The steam generation module (9) comprises: a preheater, an evaporator and a superheater; The high-temperature molten salt storage tank (3) is connected to the working fluid input port of the superheater via a pipeline, the working fluid output port of the superheater transports the molten salt working fluid to the evaporator and the preheater in sequence via a pipeline, and the working fluid output port of the preheater is connected to the low-temperature molten salt storage tank (5) and the salt mixing tank (7) via a pipeline.

6. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 1 is characterized in that: It also includes a steam turbine generator module and a heating module; The input port of the steam turbine generator module is connected to the steam generating module (9) for obtaining steam emitted by the steam generating module (9), the steam extraction pipeline of the steam turbine generator module is respectively connected to the heating module and the heat user (21), and the exhaust steam pipeline of the steam turbine generator module is respectively connected to the heating module and the heat user (21) so as to use the heat energy carried by the steam to provide heat for the heat user (21) and convert it into electric energy.

7. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 6 is characterized in that: The steam turbine generator module comprises: a steam extraction back pressure steam turbine generator (10) and a steam condensing steam turbine generator (11); Wherein: the steam input port of the extraction back-pressure steam turbine generator (10) is connected to the steam generation module (9) as the input port of the steam turbine generator module, and is used to obtain steam emitted by the steam generation module (9) for power generation; the extraction steam pipeline of the extraction back-pressure steam turbine generator (10) is respectively connected to the heating module and the heat user (21); the exhaust steam pipeline of the extraction back-pressure steam turbine generator (10) is respectively connected to the heating module, the heat user (21) and the condensing steam turbine generator (11); and the steam output port of the extraction back-pressure steam turbine generator (10) is connected to the steam input port of the condensing steam turbine generator (11); The condensing steam turbine generator (11) is used to obtain steam and exhaust steam output by the extraction back-pressure steam turbine generator (10) to generate electricity.

8. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 7 is characterized in that: The heating module comprises: a steam-water heat exchanger (19) and a water-water heat exchanger (20); The water-to-water heat exchanger (20) is used to receive the return water of the heat user (21) and perform a primary heat exchange, and the steam-to-water heat exchanger (19) is used to receive the return water of the heat user (21) after the primary heat exchange and perform a secondary heat exchange to heat the return water of the heat user (21) to a preset heating temperature.

9. The user-side photovoltaic thermal molten salt energy storage cogeneration system according to claim 1 is characterized in that: Also included is a main control module; The main control module is used to obtain the electricity demand of the electricity user (22) and the heating demand of the heat user (21), and the main control module is electrically connected to the photovoltaic power generation module (1), the molten salt trough concentrating solar collector module (2), the molten salt electric heating module (24), the molten salt energy storage module (26) and the steam generation module (9) respectively, and is used to coordinate the operation of each module, and according to the electricity demand of the electricity user (22) and the heating demand of the heat user (21), control the photovoltaic power generation module (1) and the steam generation module (9) to generate electricity and steam accordingly.

10. The user-side photovoltaic thermal molten salt energy storage combined heat and power system according to claim 9, characterized in that: The main control module is also electrically connected to the power grid (25) and is used to input valley electricity from the power grid (25) into the molten salt electric heating module (24) so ​​as to convert the electric energy transmitted by the power grid (25) into thermal energy.

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