Pumped storage system based on waste salt mine

Abstract

The invention provides a pumped storage system based on a waste salt mine. The pumped storage system comprises an upper reservoir and a lower reservoir. The upper reservoir is a first salt mine with a sealed structure, and pressure gas is contained in the first salt mine; a solution is stored in the lower reservoir; a pump turbine is arranged between the upper reservoir and the lower reservoir; when the pump turbine pumps a solution in the lower reservoir to the upper reservoir, gas in the upper reservoir is compressed, so that electric energy is converted into elastic potential energy of high-pressure gas to be temporarily stored; when the water pump turbine discharges the solution in the upper reservoir to the lower reservoir, the elastic potential energy of the high-pressure gas in the upper reservoir is released, the solution pushes the water pump turbine to generate electricity, and the elastic potential energy of the high-pressure gas is converted into electric energy. The closed / waste salt mine is turned into wealth, so that land occupation resources, structural damage and environmental pollution are reduced, and the comprehensive social problems of resource waste and the like are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of pumped storage, and in particular relates to a pumped storage system based on an abandoned salt mine. Background Art

[0002] With the introduction of the national dual-carbon strategy, my country's new energy power generation such as hydropower, wind power, nuclear power and photovoltaic power generation has gained a new round of development opportunities. Pumped storage is a low-carbon, green, flexible and clean energy storage method with reliable technology, optimal cost and scalable development in the current power system. When electricity consumption is low, water is pumped from the lower reservoir to the upper reservoir through electricity, and water is released to generate electricity during peak electricity consumption. It has the advantages of flexible startup and fast regulation speed, which is conducive to making up for the intermittent and volatile shortcomings of new energy, improving the flexibility and stability of the power system, and is conducive to the consumption of clean energy generation and realization of more efficient energy system operation.

[0003] Most cities in Jiangsu Province are plain cities with developed industries, large electricity loads, and heavy peak-shaving and valley-filling tasks. However, the construction of traditional pumped-storage power stations is restricted by many factors such as topography, land occupation, engineering costs, and ecological and environmental protection. It is difficult to find natural high-drop terrain conditions suitable for large-scale surface pumped-storage power stations. This also leads to the existing technology of using the difference in the drop of upstream and downstream reservoirs for pumped storage, which cannot be well applied to plain cities.

[0004] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Invention content

[0005] The purpose of the present invention is to provide a pumped storage system based on an abandoned salt mine to at least solve the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A pumped storage system based on an abandoned salt mine, the pumped storage system comprising an upper reservoir and a lower reservoir;

[0008] The upper reservoir is a first salt mine with a sealed structure, and there is pressurized gas in the first salt mine;

[0009] The lower reservoir contains a solution;

[0010] A water pump turbine is arranged between the upper reservoir and the lower reservoir, the water pump turbine extends to the bottom of the upper reservoir through a pipeline, and the water pump turbine extends to the bottom of the lower reservoir through a pipeline;

[0011] The pump turbine is a variable speed constant frequency pump turbine;

[0012] When there is surplus electric energy, the pump turbine is used as a water pump to pump the solution in the lower reservoir to the upper reservoir. The gas in the upper reservoir is compressed, so that the electric energy is converted into the elastic potential energy of the compressed gas and is temporarily stored. The solution flows from the lower reservoir along the water diversion pipeline in the reverse direction through the tailwater pipe, the runner, the movable guide vane, the fixed guide vane, and the volute components into the upper reservoir.

[0013] When power generation is needed, the pump turbine is used as a water turbine to discharge the solution in the upper reservoir to the lower reservoir, and the elastic potential energy of the compressed gas in the upper reservoir is released, so that the solution drives the pump turbine to generate electricity, and the elastic potential energy of the compressed gas is converted into electrical energy; wherein, the energy contained in the pressure energy of the compressed gas in the upper reservoir drives the solution through the volute and the guide vane grid of the guide vane body and into the blade grid of the turbine, driving the turbine to rotate around the main axis to perform work; the rotating turbine drives the motor to generate electricity, and the fluid flowing out of the turbine enters the tailwater section, completes the recovery of the residual head of the working water body in the tailwater section, and finally flows into the lower reservoir.

[0014] As described above, for the pumped storage system based on abandoned salt mines, preferably, when the variable speed constant frequency water pump turbine is operated as a water pump, the design parameters are as follows:

[0015] Design head: H pr =787.5m, design operating speed: n pr =2598.0762r / min, design flow rate: Q pr =4.3189m 3 / s, design power: N pr =43381.1kW, specific speed: n ps =125.547m·kw; Maximum overload head: H pmax =1050m, maximum lift speed: n pmax =3000r / min, maximum head flow: Q pmax =4.9870m 3 / s, maximum lift power: N pmax =66789.5kW; minimum water head: H pmin =0m.

[0016] For the pumped storage system based on abandoned salt mine as described above, preferably, when the variable speed constant frequency pump turbine is operated as a turbine, the design parameters are as follows: Design water head: H r1 =787.5m, design flow rate: Q r1 =4.0166m 3 / s, design speed: n r1 =2416.2r / min, specific speed: n s1 =107.26m·kw, single turbine design power: N r1=34296.1kW; Maximum water head: H max1 =1050m, maximum water head speed: n max1 =2790r / min, maximum head flow: Q max1 =4.6379m 3 / s, maximum head power: N max1 =52802.3kW.

[0017] As described above, the pumped storage system based on abandoned salt mines, preferably, the outlet placement angle of the runner blade is: β p2 =36°, runner outlet diameter: D p2 =0.7972m, runner outlet channel thickness: B p2 =0.05204m, absolute flow angle of fluid at runner outlet: α p2 =27°, wheel inlet inner side (hub) diameter: D p1a =0.24945m, blade placement angle on the inner side of the runner inlet: β p1a =43.07°, outer diameter of runner inlet: D p1c =0.4787m, the inlet angle of the outer blade of the runner is: β p1c =25.98°, runner inlet middle side diameter: D p1b =0.3549m, blade inlet placement angle on the middle side of the runner: β p1b =33.31°, diameter of the water suction pipe at the runner inlet: D pg =0.1463m;

[0018] When the variable speed constant frequency pump turbine is operated as a water pump, the operating parameters are as follows: The peripheral speed of the runner outlet: u p2 =133.276m / s, circumferential velocity of fluid at runner outlet: v up2 =65.265m / s, axial velocity of fluid at runner outlet: v mp2 =31.725m / s, absolute velocity of fluid at runner outlet: v p2 =69.881m / s, circumferential speed of the inner side of the runner inlet: u p1a =33.934m / s, outer peripheral speed of runner inlet: u p1c =65.116m / s, circumferential speed of the middle side of the runner inlet: u p1b =48.279m / s;

[0019] When the variable speed constant frequency pump turbine is operated as a turbine, the operating parameters are as follows: The peripheral speed of the runner outlet: u t2 =129.95m / s, circumferential velocity of fluid at runner outlet: v ut2 =57.91m / s, axial velocity of fluid at runner outlet: vmt2 =29.5045m / s, absolute velocity of fluid at runner outlet v t2 =64.990m / s. Peripheral speed of the inner side of the runner inlet: u t2a =31.560m / s, outer peripheral speed of runner inlet: u t2c =60.558m / s, circumferential speed of the middle side of the runner inlet: u t2b =44.899m / s.

[0020] As described above, in the pumped storage system based on abandoned salt mines, preferably, the gas in the first salt mine is natural gas or air; and the solution in the lower reservoir is saturated brine.

[0021] As described above, the pumped storage system based on abandoned salt mines, preferably, the first salt mine is connected with a gas supply pipe, and the gas supply pipe is used to supply gas to the first salt mine.

[0022] As described above, in the pumped storage system based on an abandoned salt mine, preferably, the lower reservoir is a second salt mine with a sealed structure, and a solution is stored in the second salt mine; a water supply pipe is connected to the second salt mine, and the water supply pipe is used to replenish the solution in the second salt mine.

[0023] As described above, in the pumped storage system based on abandoned salt mines, preferably, the first salt mine is also equipped with a water supply pipe, and the second salt mine is also equipped with an air supply pipe.

[0024] The pumped storage system based on abandoned salt mines as described above preferably utilizes an above-ground reservoir as the lower reservoir.

[0025] As described above, in the pumped storage system based on abandoned salt mines, preferably, the water pump turbine is located on the surface.

[0026] Beneficial effects:

[0027] In the pumped storage system, abandoned salt mines are used as liquid storage containers, and pressurized gas in the abandoned salt mines is used as energy storage medium, while the solution in the lower reservoir is only used as energy conversion medium, thus completely abandoning the technical concept of using water with high potential difference as energy storage medium in the prior art. As a result, the pumped storage system completely breaks the shackles of terrain without natural high drop, realizes effective storage and efficient use of water energy, saves the construction costs of upper and lower reservoirs of traditional pumped storage power stations, and realizes the transformation of closed / abandoned salt mines into treasures, thereby reducing land occupation resources and structural damage and environmental pollution, and solving comprehensive social problems such as resource waste.

[0028] The solution content and gas content in the salt mine can be adjusted through the water supply pipe and the air supply pipe, thereby realizing the adjustment of the water-air ratio in the upper reservoir and the lower reservoir, ensuring that the water pump turbine does not cavitate and cavitation occurs, and maintaining a certain pressure in the lower reservoir, so that the system can meet the suction height requirements during the working process.

[0029] The pump turbine adopts a variable speed constant frequency pump turbine, which can ensure high-efficiency energy conversion within the entire range of water pressure head changes. It can greatly improve the energy conversion density of the energy storage gas and adapt to the entire range of water pressure head of the energy storage power station. The energy conversion process is more efficient and has lower losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting part of the present application are used to provide a further understanding of the invention. The exemplary embodiments and descriptions of the invention are used to explain the invention and do not constitute an improper limitation on the invention. Among them:

[0031] Figure 1 A schematic diagram of the structure of a pumped storage system according to an embodiment of the present invention;

[0032] Figure 2 A schematic structural diagram of a pumped storage system according to another embodiment of the present invention;

[0033] Figure 3 A schematic diagram of the structure of a pump turbine according to an embodiment of the present invention;

[0034] Figure 4 A cross-sectional view of a pump turbine that is an embodiment of the present invention;

[0035] Figure 5 A schematic diagram of the runner structure of a pump turbine according to an embodiment of the present invention.

[0036] In the figure: 1. Upper reservoir; 2. Lower reservoir; 3. Pump turbine; 4. Air supply pipe; 5. Water supply pipe. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0038] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, they can be fixedly connected or detachably connected; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0040] According to the specific embodiments of the present invention, Figure 1-5 As shown, the present invention provides a pumped storage system based on an abandoned salt mine, and the pumped storage system includes an upper reservoir 1 and a lower reservoir 2.

[0041] The upper reservoir 1 is a first salt mine with a sealed structure, and there is pressurized gas in the first salt mine.

[0042] The lower reservoir 2 contains a solution.

[0043] A pump-turbine 3 is provided between the upper reservoir 1 and the lower reservoir 2. The pump-turbine 3 extends to the bottom of the upper reservoir 1 through a pipeline, and the pump-turbine 3 extends to the bottom of the lower reservoir 2 through a pipeline; the pump-turbine is a variable speed constant frequency pump-turbine.

[0044] When electric energy is surplus, the variable speed constant frequency pump turbine is used as a water pump to pump the solution in the lower reservoir 2 to the upper reservoir 1. The gas in the upper reservoir 1 is compressed, so that the electric energy is converted into the elastic potential energy of the high-pressure gas and is temporarily stored; wherein, the solution flows from the lower reservoir along the water diversion pipeline in the reverse direction through the tailwater pipe, the impeller, the movable guide vane, the fixed guide vane, and the volute components, and flows back to the upper reservoir.

[0045] When power generation is required, the pump turbine is used as a water turbine to discharge the solution in the upper reservoir 1 to the lower reservoir 2. The elastic potential energy of the gas in the upper reservoir 1 is released, so that the solution drives the pump turbine 3 to generate electricity, and the elastic potential energy of the gas is converted into electrical energy; wherein, the energy contained in the pressure energy of the gas in the upper reservoir drives the solution through the volute, the guide vane grid of the guide vane body, the impingement, and the blade grid of the turbine, driving the turbine to rotate around the main axis to perform work; the turbine drives the motor to generate electricity, and the fluid flowing out of the turbine enters the tailwater section, completes the recovery of the residual head of the working water body in the tailwater section, and finally flows into the lower reservoir.

[0046] In the pumped storage system, an abandoned salt mine is used as the upper reservoir 1, and the pressurized air in the abandoned salt mine is used as the energy storage medium, while the solution in the lower reservoir 2 is only used as the energy conversion medium, thereby completely abandoning the technical concept of using water with a high potential difference as the energy storage medium in the prior art, and thus the pumped storage system completely breaks the shackles of the terrain without a natural high drop; specifically, when it is necessary to store electric energy, the pump turbine 3 pumps the solution in the lower reservoir 2 to the upper reservoir 1, and the gas in the upper reservoir 1 is compressed, so that the electric energy is converted into the elastic potential energy of the high-pressure gas and is temporarily stored; when it is necessary to release electric energy, the pump turbine 3 discharges the solution in the upper reservoir 1 to the lower reservoir 2, and the elastic potential energy of the high-pressure gas in the upper reservoir 1 is released, so that the solution drives the pump turbine 3 to generate electricity, and the elastic potential energy of the high-pressure gas is converted into electric energy.

[0047] In areas rich in salt resources, huge underground spaces are formed after the salt resources are mined, and they have natural height differences and abundant water resources, which provide good potential energy and geographical conditions for the conversion of closed / abandoned mines into pumped-storage power stations. While reducing land occupation and landscape damage, it can also reduce the investment and construction cycle of power station construction. It perfectly solves the problem that large-scale pumped-storage power stations cannot be built on the surface in plain areas due to the lack of natural high drop conditions. In addition, the pumped-storage system reuses abandoned salt mine resources, is more environmentally friendly, and has outstanding benefits.

[0048] Abandoned underground salt mines are used as energy storage power stations. Reasonable use of the surplus pressure in the abandoned mines can form good pressure difference conditions for the units, form effective storage and efficient use of water energy, reduce environmental restoration costs, realize resource recycling, and absorb new energy and conventional power generation. The high construction costs of the upper and lower reservoirs of traditional pumped-storage power stations can be saved, and the problem of power matching nearby the power grid can be solved. The pumped-storage system has low requirements on the terrain. In areas where the terrain conditions are not suitable for the construction of pumped-storage power stations or even lack water resources, it provides a pumped-storage solution that turns waste into treasure.

[0049] It can achieve effective storage and efficient use of water energy, save the construction costs of the upper and lower reservoirs of traditional pumped storage power stations, and turn closed / abandoned salt mines into treasures, thereby reducing comprehensive social problems such as land occupation resources and structural damage, environmental pollution, and resource waste.

[0050] In one embodiment of the present application, when the variable speed constant frequency pump turbine is operated as a water pump, the design parameters are as follows:

[0051] Design head: H pr =787.5m, design operating speed: n pr =2598.0762r / min, design flow rate: Q pr=4.3189m 3 / s, design power: N pr =43381.1kW, specific speed: n ps =125.547m·kw; Maximum overload head: H pmax =1050m, maximum lift speed: n pmax =3000r / min, maximum head flow: Q pmax =4.9870m 3 / s, maximum lift power: N pmax =66789.5kW; minimum water head: H pmin =0m.

[0052] In this embodiment, when the variable speed constant frequency pump turbine is operated as a water pump, the design efficiency is: η pr =93%, the reaction degree of the pump-turbine: λ=0.766407, the pump-turbine can be overloaded by increasing the speed.

[0053] In one embodiment of the present application, a pump-turbine designed according to a water pump operating condition can satisfy the design operating condition of the water turbine operating condition by only changing the speed of the pump-turbine according to the condition of equal reaction degree.

[0054] When the variable speed constant frequency pump turbine operates as a turbine, the design parameters are as follows: Design head: H r1 =787.5m, design flow rate: Q r1 =4.0166m 3 / s, design speed: n r1 =2416.21r / min, specific speed: n s1 =107.26m·kw, single turbine design power: N r1 =34296.1kW; Maximum water head: H max1 =1050m, maximum water head speed: n max1 =2790r / min, maximum head flow: Q max1 =4.6379m 3 / s, maximum head power: N max1 =52802.3kW.

[0055] Where: Turbine runner inlet and outlet axial speed: v mt1 =v mt2 =29.505m / s; turbine runner blade inlet placement angle: β t1 =36°; Turbine runner blade outlet placement angle:

[0056] In one embodiment of the present application, the runner blade outlet placement angle is: βp2 =36°, runner outlet diameter: D p2 =0.97972m, runner outlet channel thickness: B p2 =0.05204m, absolute flow angle of fluid at runner outlet: α p2 =27°, wheel inlet inner side (hub) diameter: D p1a =0.24945m, blade placement angle on the inner side of the runner inlet: β p1a =43.07°, outer diameter of runner inlet: D p1c =0.4787m, the inlet angle of the outer blade of the runner is: β p1c =25.98°, runner inlet middle side diameter: D p1b =0.3549m, blade inlet placement angle on the middle side of the runner: β p1b =33.31°, diameter of the water suction pipe at the runner inlet: D pg =0.4163m.

[0057] When the variable speed constant frequency pump turbine is operated as a water pump, the operating parameters are as follows: The peripheral speed of the runner outlet: u p2 =133.276m / s, circumferential velocity of fluid at runner outlet: v up2 =62.265m / s, axial velocity of fluid at runner outlet: v mp2 =31.725m / s, absolute velocity of fluid at the rotor outlet: v p2 =69.881m / s, circumferential speed of the inner side of the runner inlet: u p1a =33.934m / s, outer peripheral speed of runner inlet: u p1c =65.116m / s, circumferential speed of the middle side of the runner inlet: u p1b =48.279m / s.

[0058] When the variable speed constant frequency pump turbine is operated as a turbine, the operating parameters are as follows: The peripheral speed of the runner outlet: u t2 =129.95m / s, circumferential velocity of fluid at runner outlet: v ut2 =57.91m / s, axial velocity of fluid at runner outlet: v mt2 =29.5045m / s, absolute velocity of fluid at runner outlet v t2 =64.990m / s. Peripheral speed of the inner side of the runner inlet: u t2a =31.560m / s, outer peripheral speed of runner inlet: u t2c =60.558m / s, circumferential speed of the middle side of the runner inlet: u t2b =44.899m / s.

[0059] The gas in the first salt mine is natural gas or air. In one embodiment of the present application, natural gas has good compression performance and is a good energy storage medium. After the sealed first salt mine is filled with solution, the natural gas is compressed and accumulates elastic potential energy, which can convert electrical energy into the elastic potential energy of compressed natural gas for storage as much as possible; using air can save costs; and the process of compressing natural gas or air is located in an underground sealed salt mine, and the entire energy conversion process is safe and harmless, with little impact on the surrounding environment, and is more environmentally friendly and sustainable.

[0060] The solution in the lower reservoir 2 is saturated brine. In one embodiment of the present application, the saturated brine is incompressible. The saturated brine is used as an energy conversion medium instead of an energy storage medium. Its incompressibility can ensure the maximum efficiency conversion between electrical energy and natural gas elastic potential energy, thereby minimizing the energy loss and dissipation during the energy conversion process.

[0061] The first salt mine is connected with a gas supply pipe 4, which is used to supply gas to the first salt mine. In one embodiment of the present application, during the operation of the pumped storage system, gas can be supplied to the first salt mine through the gas supply pipe 4 according to the need for energy density storage in the first salt mine and the degree of gas loss in the first salt mine, so as to ensure that the first salt mine always has the best energy storage state.

[0062] The lower reservoir 2 is a second salt mine with a sealed structure, and there is a solution in the second salt mine. In one embodiment of the present application, the lower reservoir 2 also selects an abandoned underground salt mine as a liquid storage container, which can reduce the land mining cost as much as possible, and realize the transformation of waste into treasure, and minimize the impact of the pumped storage system on the surface environment.

[0063] In this embodiment, the first salt mine and the second salt mine can be at the same elevation, and there is no need for a large height difference between the two. In addition, the first salt mine and the second salt mine can use sealed salt mines of the same volume, which must be water-tight and air-tight.

[0064] The second salt mine is connected with a water supply pipe 5, which is used to replenish the solution in the second salt mine. In one embodiment of the present application, the solution in the second salt mine will have a certain amount of loss during the transmission and conversion process. By setting the water supply pipe 5, the amount of solution in the second salt mine is replenished in time, thereby ensuring that the pumped storage system has sufficient energy conversion medium and ensuring that the pumped storage system has good operating efficiency.

[0065] The first salt mine is also equipped with a water supply pipe 5, and the second salt mine is also equipped with an air supply pipe 4. In one embodiment of the present application, the first salt mine and the second salt mine are both equipped with a water supply pipe 5 and an air supply pipe 4, through which the solution content and the gas content in the salt mine can be adjusted, thereby adjusting the water-air ratio in the upper reservoir 1 and the lower reservoir 2, ensuring that the water pump turbine 3 does not cavitate and cavitation occurs, and maintaining a certain pressure in the lower reservoir 2, so that the system can meet the requirements of the suction height during the working process.

[0066] In another embodiment of the present application, an above-ground reservoir is used as the lower reservoir. As another embodiment of the present application, when there is only one salt mine, the lower reservoir 2 can be constructed as a pool on the ground, and the above-ground reservoir can be constructed near the first salt mine, which can reduce the construction difficulty of the pumped storage system.

[0067] The pump turbine 3 is a variable speed constant frequency pump turbine. In one embodiment of the present application, the pump turbine 3 adopts a variable speed constant frequency pump turbine, which can ensure that high-efficiency energy conversion can be completed within the full range of the water pressure head, and can greatly improve the energy conversion density of the energy storage gas, adapt to the full range of the water pressure head of the energy storage power station, and the energy conversion process is more efficient and has lower losses.

[0068] In this embodiment, the basic parameters of the components of the pump turbine device are determined according to the determined unit operation law and various hydraulic parameters. According to the determined basic parameters, the guide vane and blade placement angle, change of flow channel width, blade thickness and other measures are taken to eliminate the vortex in the flow channel and the attack angle at the blade entrance, realize the cut-in and cut-out of the water flow, and achieve the pre-fetching operation efficiency.

[0069] When the turbine is operating, the energy contained in the high-pressure gas pressure energy in the upper reservoir 1 is used to convert the water flow pressure into a velocity water flow with a certain flow rate and direction through the volute and the guide vane grid of the guide vane body, and then tangentially rush into the blade grid of the turbine in the working section, driving the turbine to rotate around its main axis and work at a speed of 2416.21r / min; the turbine drives the doubly fed motor to generate electricity through the work it does, and the saturated brine in the first salt mine flows into the tailwater section through the turbine, and completes the conversion of the remaining excess water head in the circulating water in the tailwater section, and finally flows into the lower reservoir 2, waiting for the pumping process.

[0070] When the pumping process begins, the pump-turbine runs in reverse as a pump at a speed of 2598.0762r / min. The saturated brine flows from the lower reservoir 2 along the water diversion pipeline in the reverse direction through the tailwater pipe, impeller, movable guide vanes, fixed guide vanes, volute and other components, and finally flows back to the upper reservoir 1. When the gas pressure in the two reservoirs reaches equilibrium, a pumping cycle is completed.

[0071] The water pump turbine 3 is located on the ground surface. In one embodiment of the present application, the water pump turbine 3 can be set on the ground surface close to the salt mine, which has stronger adaptability.

[0072] It should be understood that the above description is merely exemplary and the embodiments of the present application do not limit this.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A pumped storage system based on an abandoned salt mine, characterized in that: The pumped storage system comprises an upper reservoir and a lower reservoir; The upper reservoir is a first salt mine with a sealed structure, and there is pressurized gas in the first salt mine; The lower reservoir contains a solution; A water pump turbine is arranged between the upper reservoir and the lower reservoir, the water pump turbine extends to the bottom of the upper reservoir through a pipeline, and the water pump turbine extends to the bottom of the lower reservoir through a pipeline; The pump turbine is a variable speed constant frequency pump turbine; When there is surplus electric energy, the pump turbine is used as a water pump to pump the solution in the lower reservoir to the upper reservoir. The gas in the upper reservoir is compressed, so that the electric energy is converted into the elastic potential energy of the compressed gas and is temporarily stored. The solution flows from the lower reservoir along the water diversion pipeline in the reverse direction through the tailwater pipe, the runner, the movable guide vane, the fixed guide vane, and the volute components into the upper reservoir. When power generation is needed, the pump turbine is used as a water turbine to discharge the solution in the upper reservoir to the lower reservoir, and the elastic potential energy of the compressed gas in the upper reservoir is released, so that the solution drives the pump turbine to generate electricity, and the elastic potential energy of the compressed gas is converted into electrical energy; wherein, the energy contained in the pressure energy of the compressed gas in the upper reservoir drives the solution through the volute and the guide vane grid of the guide vane body and into the blade grid of the turbine, driving the turbine to rotate around the main axis to perform work; the rotating turbine drives the motor to generate electricity, and the fluid flowing out of the turbine enters the tailwater section, completes the recovery of the residual head of the working water body in the tailwater section, and finally flows into the lower reservoir.

2. The pumped storage system based on abandoned salt mine according to claim 1 is characterized in that: When the variable speed constant frequency pump turbine operates as a water pump, the design parameters are as follows: Design head: H pr =787.5m, design operating speed: n pr =2598.0762r / min, design flow rate: Q pr =4.3189m 3 / s, design power: N pr =43381.1kW, specific speed: n ps =125.547m·kw; Maximum overload head: H pmax =1050m, maximum lift speed: n pmax =3000r / min, maximum head flow: Q pmax =4.9870m 3 / s, maximum lift power: N pmax =66789.5kW; minimum water head: H pmin =0m.

3. The pumped storage system based on abandoned salt mine according to claim 2 is characterized in that: When the variable speed constant frequency pump turbine operates as a turbine, the design parameters are as follows: Design head: H r1 =787.5m, design flow rate: Q r1 =4.0166m 3 / s, design speed: n r1 =2416.21r / min, specific speed: n s1 =107.26m·kw, single turbine design power: N r1 =34296.1kW; Maximum water head: H max1 =1050m, maximum water head speed: n max1 =2790r / min, maximum head flow: Q max1 =4.6379m 3 / s, maximum head power: N max1 =52802.3kW.

4. The pumped storage system based on abandoned salt mine according to any one of claims 1 to 3, characterized in that: Runner blade outlet placement angle: β p2 =36°, runner outlet diameter: D p2 =0.97972m, runner outlet channel thickness: B p2 =0.05204m, absolute flow angle of fluid at runner outlet: α p2 =27°, wheel inlet inner side (hub) diameter: D p1a =0.24945m, blade placement angle on the inner side of the runner inlet: β p1a =43.07°, outer diameter of runner inlet: D p1c =0.4787m, the inlet angle of the outer blade of the runner is: β p1c =25.98°, runner inlet middle side diameter: D p1b =0.3549m, blade inlet placement angle on the middle side of the runner: β p1b =33.31°, diameter of the water suction pipe at the runner inlet: D pg =0.4163m; When the variable speed constant frequency pump turbine is operated as a water pump, the operating parameters are as follows: The peripheral speed of the runner outlet: u p2 =133.276m / s, circumferential velocity of fluid at runner outlet: v up2 =62.265m / s, axial velocity of fluid at runner outlet: v mp2 =31.725m / s, absolute velocity of fluid at runner outlet: v p2 =69.881m / s, circumferential speed of the inner side of the runner inlet: u p1a =33.934m / s, outer peripheral speed of runner inlet: u p1c =65.116m / s, circumferential speed of the middle side of the runner inlet: u p1b =48.279m / s; When the variable speed constant frequency pump turbine is operated as a turbine, the operating parameters are as follows: The peripheral speed of the runner outlet: u t2 =129.95m / s, circumferential velocity of fluid at runner outlet: v ut2 =57.91m / s, axial velocity of fluid at runner outlet: v mt2 =29.5045m / s, absolute velocity of fluid at runner outlet v t2 =64.990m / s. Peripheral speed of the inner side of the runner inlet: u t2a =31,560m / s, outer peripheral speed of runner inlet: u t2c =60.558m / s, circumferential speed of the middle side of the runner inlet: u t2b =44.899m / s.

5. The pumped storage system based on abandoned salt mine according to claim 4 is characterized in that: The gas in the first salt mine is natural gas or air; the solution in the lower reservoir is saturated brine.

6. The pumped storage system based on abandoned salt mine according to claim 5 is characterized in that: The first salt mine is connected with a gas supply pipe, and the gas supply pipe is used to supply gas to the first salt mine.

7. The pumped storage system based on abandoned salt mine according to claim 6 is characterized in that: The lower reservoir is a second salt mine with a sealed structure, and a solution is stored in the second salt mine; a water supply pipe is connected to the second salt mine, and the water supply pipe is used to replenish the solution into the second salt mine.

8. The pumped storage system based on abandoned salt mine according to claim 7 is characterized in that: The first salt mine is also equipped with a water supply pipe, and the second salt mine is also equipped with an air supply pipe.

9. The pumped storage system based on abandoned salt mine according to claim 6, characterized in that: An above-ground reservoir is used as the lower reservoir.

10. The pumped storage system based on abandoned salt mine according to any one of claims 1 to 3, characterized in that: The pump turbine is located on the ground surface.

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