New energy multipotency coupling complementary joint storage systemTechnical Field
The invention relates to a wind-solar energy storage integrated technology, in particular to a new energy multi-energy coupling complementary combined storage system.
Background
With the continued growth of global energy production and consumption, fossil energy is increasingly depleted and energy crisis has become a common problem worldwide. Therefore, new energy technology rapidly bursts in recent years, especially renewable energy sources such as solar energy, wind energy and the like. However, because new energy power generation such as wind power, light energy and the like has volatility and discontinuity, large-scale grid connection of the new energy power generation brings a plurality of challenges to safe and stable operation of a power grid, and the energy storage technology is exploded.
The energy storage technology can effectively realize demand side management, play a role in peak clipping and valley filling, improve the daily load rate of the power system and improve the overall operation efficiency of the power grid. Energy storage modes are classified into mechanical, electrical, electrochemical, thermal methods and chemical types according to the energy storage modes. Currently, various energy storage modes are widely applied to pumped storage, compressed air energy storage, molten salt energy storage and the like.
The compressed air energy storage is an energy storage mode of compressing air by using electric energy in the low-load period of the power grid, sealing the air in the air storage container at high pressure and releasing the compressed air in the peak load period of the power grid to push the turbine generator to generate power. In the traditional compressed air energy storage system, most of energy loss is caused by the fact that compression heat in the compression process is abandoned, the circulation efficiency of the system is low, and meanwhile, fuel such as natural gas and the like is consumed in the energy release expansion process to carry out afterburning to heat the compressed air.
The molten salt energy storage technology is to utilize the temperature difference of molten salt in the heating or cooling process to realize heat energy storage, and the heat storage material always keeps liquid state in the whole working temperature range.
In order to solve the problem of low circulation efficiency of the traditional compressed air energy storage system, the compressed air energy storage system with heat storage is generated, so that fossil fuel is not required to be combusted when compressed air is used for generating electricity, the theoretical efficiency of the compressed air energy storage system is improved to about 70%, and the efficiency cannot be further improved mainly because the heat collection and heat exchange processes of the compressed heat are relatively extensive and are not subjected to refined recovery aiming at different temperatures, and meanwhile, the existing energy storage system also has the problems of high manufacturing cost, low equipment utilization rate and poor flexibility.
Disclosure of Invention
In order to solve the technical problems, the invention provides a system which can be coupled with a plurality of new energy sources and has flexible energy storage mode and high efficiency, and the invention provides the following technical scheme:
The novel energy multi-energy coupling complementary combined storage system mainly comprises a photovoltaic power generation system, a wind power generation system, a photo-thermal heat collection system, a compressed air energy storage system and a fused salt heat storage system, wherein the compressed air energy storage system comprises a three-stage air compressor, an air storage tank and a two-stage turbine expander;
The compression ratio of each stage of air compressor is different, and the generated compression heat is also different, so that a medium-temperature molten salt tank is added on the basis of a traditional double-tank molten salt heat storage system, sectional temperature control is carried out on each stage of air compressor and a turbine expander, and meanwhile, each device of an evaporation system is subjected to graded heat supply by utilizing the molten salt heat storage system, so that the overall heat exchange efficiency is improved.
The photovoltaic power generation system, the wind power generation system and the steam turbine generator generate electric power which is partially connected to a power grid through an electric power adjusting device and is partially used for supplying power to the three-stage air compressor;
the three-stage air compressor comprises an air compressor I, an air compressor II and an air compressor III;
the two-stage turboexpander comprises a first turboexpander and a second turboexpander;
the molten salt heat exchange system comprises a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger, which all comprise an air inlet, an air outlet, a molten salt inlet and a molten salt outlet;
The evaporation system comprises a preheater, an evaporator and a superheater which are sequentially connected, wherein the superheater is connected with a steam turbine generator;
The low-temperature molten salt tank, the first heat exchanger, the medium-temperature molten salt tank and the evaporator are connected end to end in sequence to form a first molten salt circulation;
the medium-temperature molten salt tank, the second heat exchanger, the high-temperature molten salt tank and the superheater are sequentially connected end to form a second molten salt circulation;
The molten salt inlet is connected with the low-temperature molten salt tank, and the molten salt outlet is connected with the medium-temperature molten salt tank;
the second air outlet of the heat exchanger is connected with the third air inlet of the air compressor, and the molten salt inlet is connected with the medium-temperature molten salt tank and the molten salt outlet is connected with the high-temperature molten salt tank;
the air outlet of the air compressor III is connected with the air inlet of the air storage tank III;
an air outlet of the third heat exchanger is connected with an inlet of the turbine expander I, a molten salt inlet is connected with the medium-temperature molten salt tank, and a molten salt outlet is connected with the low-temperature molten salt tank;
The air inlet of the heat exchanger IV is connected with the first outlet of the turbine expander, the air outlet is connected with the second inlet of the turbine expander a molten salt inlet is connected with a high-temperature molten salt tank the molten salt outlet is connected with a low-temperature molten salt tank;
further, the outlets of the high-temperature molten salt tank, the medium-temperature molten salt tank and the low-temperature molten salt tank are provided with molten salt pumps for forced convection of molten salt in the molten salt tank.
Furthermore, electric heaters are arranged in the high-temperature molten salt tank, the medium-temperature molten salt tank and the low-temperature molten salt tank, and the electric heaters are powered by one of a photovoltaic power generation system, a wind power generation system and low-valley electricity.
The invention has the beneficial effects that:
(1) The sectional temperature control is adopted, so that the overall heat exchange efficiency of the system can be improved;
(2) The combination of compressed air energy storage and molten salt heat storage can obviously improve the integrated comprehensive regulation capacity of the source network charge storage.
(3) The molten salt heat storage system is shared by multiple new energy sources, so that the heat storage cost can be shared, and the investment cost can be reduced.
Drawings
FIG. 1, a schematic system diagram of the present invention.
In the figure, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger and a fourth heat exchanger are arranged.
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
Example 1,
The novel energy multi-energy coupling complementary combined storage system shown in the figure 1 mainly comprises a photovoltaic power generation system, a wind power generation system, a photo-thermal heat collection system, a compressed air energy storage system and a fused salt heat storage system, wherein the compressed air energy storage system comprises an air compressor I, an air compressor II, an air compressor III, a gas storage tank, a turbo expander I and a turbo expander II;
The photovoltaic power generation system, the wind power generation system and the steam turbine generator generate electric power which is partially connected to a power grid through an electric power adjusting device and is partially used for supplying power to the three-stage air compressor;
the molten salt heat exchange system comprises a first heat exchanger 1, a second heat exchanger 2, a third heat exchanger 3 and a fourth heat exchanger 4, which all comprise an air inlet, an air outlet, a molten salt inlet and a molten salt outlet;
The evaporation system comprises a preheater, an evaporator and a superheater which are sequentially connected, wherein the superheater is connected with a steam turbine generator;
the low-temperature molten salt tank, the first heat exchanger 1, the medium-temperature molten salt tank and the evaporator are sequentially connected end to form a first molten salt circulation, and the medium-temperature molten salt tank, the second heat exchanger 2, the high-temperature molten salt tank and the superheater are sequentially connected end to form a second molten salt circulation;
The first air inlet of the heat exchanger 1 is connected with the first air outlet of the air compressor, and the air outlet of the heat exchanger is connected with the second air inlet of the air compressor;
The second air outlet of the heat exchanger 2 is connected with the third air inlet of the air compressor, and the molten salt inlet is connected with the medium-temperature molten salt tank and the molten salt outlet is connected with the high-temperature molten salt tank;
The air outlet of the air compressor III is connected with the air inlet of the air storage tank III, and the air outlet of the air storage tank III is connected with the air inlet of the heat exchanger III 3;
An air outlet of the third heat exchanger 3 is connected with an inlet of the turbine expander I, a molten salt inlet is connected with the medium-temperature molten salt tank, and a molten salt outlet is connected with the low-temperature molten salt tank;
An air inlet of the heat exchanger IV 4 is connected with an outlet of the first turboexpander, an air outlet of the heat exchanger IV is connected with an inlet of the second turboexpander, a molten salt inlet of the heat exchanger IV is connected with a high-temperature molten salt tank, and a molten salt outlet of the heat exchanger IV is connected with a low-temperature molten salt tank;
the high temperature molten salt tank, the medium temperature molten salt tank and the low temperature molten salt tank are respectively provided with a molten salt pump, and the inside of the molten salt tank is respectively provided with an electric heater, and the electric heater is powered by adopting one of a photovoltaic power generation system, a wind power generation system and low-valley electricity.
The compressed air energy storage system and the fused salt heat storage system of the invention have two modes of energy storage and energy release, and are mainly as follows:
(1) The compressed air energy storage system is in an energy storage mode, wherein the air compressor is powered by wind abandoning and photoelectric abandoning, air is compressed and stored in the air storage tank, compression heat generated in the energy storage process is respectively subjected to gradual heat exchange with molten salt, the compression heat is stored in medium-temperature molten salt and high-temperature molten salt, and the compressed air energy storage can be powered by low-valley electricity according to actual needs.
(2) The energy release mode of the compressed air energy storage system comprises the steps of generating electricity by using compressed air in an air storage tank through a turbine expander in the power grid load peak period, and heating the compressed air step by using medium-high temperature molten salt in the energy release process.
(3) The molten salt heat storage system energy storage mode is to utilize redundant heat energy and compression heat of the photo-thermal heat collection system to heat low-temperature molten salt, and store heat in medium-temperature molten salt and high-temperature molten salt;
(4) In the energy release mode of the fused salt heat storage system, in the peak period of power grid load, fused salt heat energy is used for heating compressed air in the air storage tank on one hand, and is used for heating the evaporation system on the other hand, so that high-temperature steam is generated for the steam turbine generator to generate power.
The above is only a preferred embodiment of the present invention, and it should be noted that it should be understood by those skilled in the art that several improvements and modifications can be made without departing from the technical principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.