Energy utilization system combining underground salt mine and vertical shaft and control method thereof

Abstract

This specification provides an energy utilization system and control method combining an underground salt mine and a vertical shaft, wherein the system includes: an outer tube, an inner tube, and a plugger arranged in the vertical shaft, and an annular cavity is formed between the outer tube and the inner tube; in a first state, the plugger divides the inner cavity of the outer tube into upper and lower parts that are isolated from each other, and in the upper part of the inner cavity of the outer tube, the annular cavity is connected with the inner cavity of the inner tube, forming a part of the heat medium circulation path in the heating system; in a second state, the plugger blocks the bottom of the inner tube or the annular cavity, so that the inner tube and / or the annular cavity is connected with the inner cavity of the underground salt mine through the bottom of the outer tube, forming a circulation channel for compressed gas. This solution can realize the efficient and intensive utilization mode of "vertical shaft heat exchange + underground salt mine gas storage" by only using the plugger, which improves the energy utilization efficiency while reducing the system cost, and provides an efficient, innovative, clean and friendly "energy storage + heat extraction" energy application mode.

Description

Technical Field

[0001] The present application relates to the field of energy utilization technology, and in particular to an energy utilization system combining an underground salt mine and a vertical shaft and a control method thereof. Background Art

[0002] Renewable energy such as geothermal energy has the advantages of wide distribution, safety and environmental protection, but has the disadvantages of low energy density, poor stability and difficulty in storage. Various forms of new energy storage technologies can make up for the shortcomings of renewable energy to a large extent. Therefore, the efficient use of renewable energy and new energy storage methods are the inevitable trend of green energy development.

[0003] Among the new energy storage technologies, compressed air energy storage technology has the advantages of large scale, low cost, long life, clean and pollution-free, and unlimited energy storage cycle. In addition, its energy storage / release process is accompanied by heat transmission and storage. It is a large-scale new physical energy storage technology suitable for large-scale promotion. The basic principle of compressed air energy storage technology is that during non-peak electricity consumption periods, the compressor consumes excess electricity (valley electricity, abandoned wind and abandoned solar power, etc.) to compress air to high pressure and store it in air storage tanks or underground air pockets; during peak electricity consumption periods, the high-pressure air is released and converted into electrical energy through a specially constructed gas turbine to achieve the purpose of peak shaving and valley filling of the power grid and improve the stability and reliability of the power grid.

[0004] In the existing technology, independent compressed air energy storage systems are mainly operated in charging and discharging modes. It is necessary to find suitable natural salt mines as underground gas storage devices. Salt mines are usually hundreds of meters underground. During the construction of compressed air energy storage systems, multiple vertical shafts are drilled as gas circulation pipelines. This part of the pipeline runs hundreds of meters underground, and the temperature of the surrounding rock and soil gradually increases with the depth. It is a geothermal energy that can be mined and utilized.

[0005] The existing compressed air energy storage system only uses salt caverns to store pressurized air, and the vertical shaft is used as a channel for air to flow in and out. It is impossible to effectively exploit and utilize the surrounding geothermal energy through the vertical shaft, resulting in insufficient resource exploitation and increased construction costs. Summary of the invention

[0006] The present specification provides an energy utilization system and a control method thereof combining an underground salt mine and a vertical shaft to improve energy utilization efficiency.

[0007] In order to solve the above technical problems, the first aspect of the present specification provides an energy utilization system combining an underground salt mine and a vertical shaft, comprising: an outer tube, which is used to be arranged on the inner side of the shaft wall of the vertical shaft, and the outer tube is connected to the inner cavity of the underground salt mine; an inner tube, which is used to be sleeved inside the outer tube; an annular cavity is formed between the outer tube and the inner tube; a plugger is arranged inside the outer tube and located at the bottom of the inner tube; wherein the plugger has a first state and a second state; in the first state, the plugger divides the inner cavity of the outer tube into upper and lower parts that are isolated from each other, and in the upper part of the inner cavity of the outer tube, the annular cavity is connected to the inner cavity of the inner tube, forming a part of the heat medium circulation path in the heating system; in the second state, the plugger blocks the bottom of the inner tube or the annular cavity, so that the inner tube and / or the annular cavity are connected to the inner cavity of the underground salt mine through the bottom of the outer tube, forming a gas circulation channel, and the gas circulation channel is used to circulate compressed gas.

[0008] In some embodiments, in the second state, the occluder blocks the annular cavity and connects the inner cavity of the inner tube with the inner cavity of the underground salt mine; and / or, in the second state, the occluder blocks the bottom of the inner tube and connects the annular cavity with the inner cavity of the underground salt mine.

[0009] In some embodiments, in the second state, the opening of the inner tube lumen and / or the annular cavity can be adjusted by the occluder.

[0010] In some embodiments, a pressure detection device is provided on the plug, and the pressure detection device is used to detect the air pressure value in the inner cavity of the underground salt mine.

[0011] In some embodiments, the energy utilization system also includes: a switching device having at least six ports, wherein the first port is connected to the ground opening of the annular cavity, the second port is connected to the ground opening of the inner tube cavity, the third port is used to connect to the gas compressor, the fourth port is used to connect to the expander, the fifth port is used to connect to the hot water pipe of the heating pipe, and the sixth port is used to connect to the return water pipe of the heating pipe; the third port, the fourth port, the fifth port, and the sixth port can be switched to connect to the first port and / or the second port.

[0012] The second aspect of the present specification provides a control method for an energy utilization system combining an underground salt mine and a vertical shaft, which is used for the energy utilization system described in any one of the first aspects; the control method includes: before the working condition of gas compression energy storage or gas expansion energy release, controlling the plug to switch to the second state; after the working condition of gas compression energy storage or gas expansion energy release ends, controlling the plug to switch to the first state, and controlling the heat medium in the heating system to flow through the annular cavity and the inner cavity of the inner tube.

[0013] In some embodiments, after controlling the plug to switch to the first state, and before controlling the heat medium to flow through the annular cavity and the inner tube cavity, it also includes: controlling the reduction of the air pressure in the annular cavity and obtaining the air pressure value in the inner cavity of the underground salt mine; when the air pressure value remains constant and the maintenance time reaches a predetermined time threshold, controlling the heat medium in the heating system to flow through the annular cavity and the inner tube cavity.

[0014] In some embodiments, the control method also includes: under the condition of gas compression energy storage, obtaining the air pressure value in the inner cavity of the underground salt mine; after the air pressure value reaches a preset upper pressure limit, controlling the end of the gas compression energy storage condition; and / or, when the plug is in the second state, after receiving the deflation instruction, controlling the start of the gas expansion energy release condition.

[0015] In some embodiments, the energy utilization system also includes: a switching device having at least six ports, wherein the first port is connected to the ground opening of the annular cavity, the second port is connected to the ground opening of the inner tube cavity, the third port is used to communicate with the gas compressor, the fourth port is used to communicate with the expander, the fifth port is used to communicate with the hot water pipe of the heating pipe, and the sixth port is used to communicate with the return water pipe of the heating pipe; the third port, the fourth port, the fifth port, and the sixth port can be switched to communicate with the first port and / or the second port; accordingly, controlling the heat medium in the heating system to flow through the annular cavity and the inner tube cavity includes: controlling the second port of the switching device to be connected to the fifth port, and the first port to be connected to the sixth port; before the energy utilization system operates in the gas compression energy storage condition, the third port of the switching device is controlled to be connected to the first port, or the third port of the switching device is controlled to be connected to the second port; before the energy utilization system operates in the gas expansion energy release condition, the fourth port of the switching device is controlled to be connected to the first port, or the fourth port of the switching device is controlled to be connected to the second port.

[0016] A third aspect of this specification provides a controller for executing any of the methods described in the second aspect.

[0017] The energy utilization system combining underground salt mines and vertical shafts can develop and utilize geothermal energy by using only plugs, without affecting the normal operation of compressed gas energy storage, and utilizing the time interval between gas storage and gas release, thus realizing an efficient and intensive utilization mode of "vertical shaft heat exchange + underground salt mine gas storage". In this mode, geothermal energy can be directly developed without the need for additional drilling, saving the expensive cost of vertical shaft drilling.

[0018] Due to the low thermal conductivity of rock formations and slow heat recovery, geothermal energy development has the characteristic of attenuation, which is manifested in the continuous decrease of outlet water temperature. For this, an alternating operation mode of "underground salt mine gas storage + geothermal energy development + underground salt mine gas release + geothermal energy development" can be adopted, which can make geothermal energy recover briefly during the gas storage and gas release period to meet the continuity of geothermal energy development. This underground salt mine utilization mode combines the characteristics of the two systems of geothermal energy development and compressed gas energy storage, while reducing the system cost and improving the energy utilization efficiency, providing an efficient, innovative, clean and friendly "energy storage + heat extraction" energy application mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 A schematic diagram of an energy utilization system combining an underground salt mine and a vertical shaft provided in an embodiment of this specification;

[0021] Figure 2 is a schematic diagram of the occluder in a first state;

[0022] Figure 3 A schematic diagram of the occluder in the second state under the compression energy storage condition;

[0023] Figure 4 A schematic diagram of the occluder in the second state under the condition of expansion and energy release;

[0024] Figure 5 Another schematic diagram of the occluder in the second state under the compression energy storage condition;

[0025] Figure 6 Another schematic diagram of the occluder in the second state under the expansion and energy release condition;

[0026] Figure 7 A schematic diagram of a compressed air energy storage system;

[0027] Figure 8 A schematic diagram of a control method for an energy utilization system combining an underground salt mine and a shaft provided in this specification;

[0028] Fig. 9 Another schematic diagram of a control method for an energy utilization system combining an underground salt mine and a shaft provided in this specification;

[0029] Fig.10 This is a schematic diagram of the structure of the controller provided in this manual. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0031] Mining thick salt layers or salt domes underground by water dissolution can form underground caves with good sealing properties. Due to the deep underground layer (e.g., about 1,000 meters), these caves are difficult to be used to accommodate solids and liquids, resulting in a waste of space resources.

[0032] Compressed gas energy storage technology refers to the process in which a compressor consumes excess electricity (valley electricity, abandoned wind and solar power, etc.) to compress gas to high pressure and store it in a gas storage tank during off-peak hours; during peak hours, the high-pressure gas is released and converted into electricity through a specially constructed expander, thereby achieving the purpose of peak shaving and valley filling in the power grid and improving the stability and reliability of the power grid.

[0033] Considering that underground salt mines are located deep in the natural layer and have the characteristics of high pressure and a certain degree of sealing, when implementing compressed gas energy storage technology, compressed gas can be stored in the inner cavity of underground salt mines.

[0034] This specification provides an energy utilization system combining an underground salt mine and a shaft, such as Figure 1 As shown, it includes an outer tube 10 , an inner tube 20 and an occluder 30 .

[0035] The outer pipe 10 is used to be arranged on the inner side of the shaft wall of the vertical shaft A, and the outer pipe 10 is communicated with the inner cavity of the underground salt mine B.

[0036] When mining underground salt mines, vertical shafts are usually dug underground. This solution utilizes the inner cavity of the underground salt mine to store compressed gas, utilizes the vertical shaft as a circulation channel for the compressed gas, and utilizes the vertical shaft as a heat exchange section in the heat medium circulation path.

[0037] The outermost layer of the shaft wall can be a cement shaft wall to play a role in supporting and cementing the well.

[0038] The inner tube 20 is used to be sleeved inside the outer tube 10. An annular cavity C is formed between the outer tube 10 and the inner tube 20. The inner tube 20 and the outer tube 10 can be coaxially arranged or non-coaxially arranged. Accordingly, the cross-section of the annular cavity C can be a ring formed by concentric circles or a ring formed by non-concentric circles. Of course, the cross-sectional shapes of the outer tube 10 and the inner tube 20 can also be other shapes besides a circle, and the cross-sectional shapes of the outer tube 10 and the inner tube 20 can also be different.

[0039] The occluder 30 is disposed inside the outer tube 10 and is located at the bottom of the inner tube 20. The occluder 30 has a first state and a second state.

[0040] In the first state, the plug 30 divides the inner cavity of the outer tube 10 into upper and lower parts that are isolated from each other. In the upper part of the inner cavity of the outer tube 10, the annular cavity C is connected to the inner cavity of the inner tube 20 to form a part of the heat medium circulation path in the heating system.

[0041] like Figure 2 As shown, in the first state, the low-temperature fluid as the heat medium can flow in from the ground opening of the annular cavity C and flow downward along the annular cavity C. During the flow, the heat medium exchanges heat with the well wall through the outer tube 10, absorbing the geothermal energy stored in the surrounding rock and soil, so that the temperature of the heat medium gradually increases, and the temperature of the heat medium reaches the highest above the plug 30. Due to the blocking effect of the plug 30, the fluid turns around and flows from the bottom of the inner cavity of the inner tube 20 to the wellhead.

[0042] After reaching the wellhead, the high-temperature fluid after absorbing heat flows out of the inner pipe 20, and then flows to the heat user for direct use, or flows through the heat pump for secondary heat exchange. The fluid after heat exchange at the user side or the heat pump flows in again from the ground opening of the annular cavity C to continue the next round of heat absorption cycle.

[0043] Since the heat medium exchanges heat with the well wall through the outer pipe 10, in order to increase the effective heat exchange amount of geothermal energy, the outer pipe 10 can be set to a special steel casing or a petroleum steel casing with a large thermal conductivity and strong pressure bearing capacity.

[0044] Since there is a temperature difference between the inner tube 20 and the fluid in the annular cavity C, heat is easily transferred from the inner tube 20 to the annular cavity C. In order to avoid the temperature of the hot water rising in the inner tube 20 from decreasing and to improve the effective heat exchange of geothermal energy, the inner tube 20 can be configured to use a high heat resistance pipe with low thermal conductivity and good thermal insulation performance, with a thermal conductivity of no more than 0.4W / (m·K), and strength, temperature resistance, corrosion resistance and durability that meet the design and use requirements, and with temperature difference compensation measures.

[0045] In the second state, the plugger 30 blocks the bottom of the inner tube 20 or the annular cavity C, so that the inner tube 20 and / or the annular cavity C are connected with the inner cavity of the underground salt mine through the bottom of the outer tube 10 to form a gas circulation channel, which is used to circulate compressed gas.

[0046] Compressed gas includes gas to be compressed under compression energy storage conditions, or gas to be released under expansion energy release conditions.

[0047] In some embodiments, in the second state, the plugger 30 plugs the annular cavity C and enables the inner cavity of the inner tube 20 to communicate with the inner cavity of the underground salt mine.

[0048] like Figure 3 As shown, under the compression energy storage condition, the high-pressure gas output by the compressor flows in from the ground opening of the inner tube 20, reaches the bottom of the inner tube 20 through the inner cavity of the inner tube 20, and enters the inner cavity of the underground salt mine through the gap between the plug 30 and the outer tube 10. The inner cavity pressure of the underground salt mine gradually increases, and finally the ground valve is closed.

[0049] like Figure 4 As shown, under the expansion energy release condition, the ground valve is opened, and the high-pressure gas in the inner cavity of the underground salt mine flows to the ground through the gap between the plug 30 and the outer tube 10 and the inner cavity of the inner tube 20, and the expander on the ground generates electricity.

[0050] In other embodiments, in the second state, the plugger 30 blocks the bottom of the inner tube 20 and enables the annular cavity C to communicate with the inner cavity of the underground salt mine.

[0051] like Figure 5 As shown, under the compression energy storage condition, the high-pressure gas output by the compressor flows into the ground opening of the annular cavity C, enters the inner cavity of the underground salt mine through the gap between the annular cavity C, the plug 30 and the outer tube 10, and the inner cavity pressure of the underground salt mine gradually increases, and finally the ground valve is closed.

[0052] like Figure 6 As shown, under the expansion energy release condition, the ground valve is opened, and the high-pressure gas in the inner cavity of the underground salt mine flows to the ground through the gap between the plug 30 and the outer tube 10 and the annular cavity C, and the expander to the ground generates electricity.

[0053] In some embodiments, compressed gas can be introduced and exited through either the annular cavity C or the inner cavity of the inner tube 20. The specific circumstances under which the annular cavity C is used to introduce compressed gas or the inner tube 20 is used to introduce compressed gas can be determined based on actual needs.

[0054] For example, the annular cavity C can be used as the gas flow channel. If the number of openings of the outer tube wellbore is too large and causes excessive flow loss, and it is evaluated that it is not suitable to use the outer tube 10 as the gas flow channel, it can be switched to use the inner cavity of the inner tube 20 as the gas flow channel. When switching, the valve of the inner cavity of the inner tube 20 is opened and the valve of the annular cavity C is closed.

[0055] In other embodiments, only the annular cavity C may be used as the gas circulation channel, or only the inner cavity of the inner tube 20 may be used as the gas circulation channel.

[0056] In some other embodiments, in the second state, the occluder 30 can adjust the opening of the inner cavity of the inner tube 20 and / or the annular cavity C, so that the compressed gas can be flexibly distributed between the inner tube 20 and the annular cavity C as needed.

[0057] In some embodiments, the plug 30 may include a screen tube and a rubber tube. The screen tube is a pipe with multiple through holes on the wall, and the screen tube is used to be fixed to the bottom of the inner tube 20. In the first state, the rubber tube is tightly attached to the wall of the outer tube 10 or the wall of the open hole, so as to seal the gap between the inner tube 20 and the outer tube 10 and effectively isolate the upper and lower parts of the plug.

[0058] In order to ensure the isolation and sealing effects in the first state and the second state, the plugger can be designed to have higher performance parameters, for example, a bearing pressure ≥40MPa and an effective sealing length ≥0.8m.

[0059] The energy utilization system combining underground salt mine and shaft includes underground part and ground part. The underground part may include heat preservation casing in addition to shaft and inner cavity of underground salt mine, and Figures 3 to 6 The control device 40 of the occluder 30 shown in Figures 3 to 6 The switch valve, switching device, and pressure detection device 70 shown in FIG.

[0060] The control device 40 of the occluder 30 can be arranged on the ground. The control device 40 can be mechanically controlled, hydraulically controlled or cable controlled.

[0061] like Figures 2 to 6 As shown, a first switch valve 50 may be provided at the ground opening of the annular cavity, and a second switch valve 60 may be provided at the ground opening of the inner cavity of the inner tube 20 .

[0062] exist Figure 2 In the first working state of the plugging device 30 shown, the first switch valve 50 and the second switch valve 60 are open. Figure 3 and Figure 4 In the second state of the plugging device 30, the first switch valve 50 is open and the second switch valve 60 is closed. Figure 5 and Figure 6 In the second state of the occluder 30 shown, the first switch valve 50 is closed and the second switch valve 60 is open.

[0063] The pressure detection device can be used to detect the air pressure value in the inner cavity of an underground salt mine.

[0064] exist Figure 2 In the first working state of the plugging device 30 shown, the pressure detection device is used to detect the air pressure value in the inner cavity of the underground salt mine. After the plugging device 30 is switched from the second state to the first state, the first switch valve 50 or the second switch valve 60 can be opened, and then it is determined whether the first state is successfully switched according to the detection value of the pressure detection device. Specifically, if the detection value of the pressure detection device is constant and maintained for a predetermined time threshold, it can be determined that the plugging device 30 is successfully switched to the first state. When ensuring that the first state is successfully switched, the first switch valve 50 and the second switch valve 60 are opened.

[0065] exist Figure 3 In the second state of the plugging device 30, the pressure detection device is used to detect the air pressure value in the inner cavity of the underground salt mine, and can control whether the first switch valve 50 is closed according to the air pressure value. Specifically, during the process of compressed gas entering the inner cavity of the underground salt mine, the pressure detection device continuously detects the air pressure value in the inner cavity of the underground salt mine, and controls the closing of the first switch valve 50 after the air pressure value reaches the preset upper pressure limit. Then, the pressure detection device can continue to monitor the air pressure value in the inner cavity of the underground salt mine.

[0066] exist Figure 5 In the second state of the plugging device 30, the pressure detection device is used to detect the air pressure value in the inner cavity of the underground salt mine, and can control whether the second switch valve 60 is closed according to the air pressure value. Specifically, during the process of compressed gas entering the inner cavity of the underground salt mine, the pressure detection device continuously detects the air pressure value in the inner cavity of the underground salt mine, and controls the closing of the second switch valve 60 after the air pressure value reaches the preset upper pressure limit. Then, the pressure detection device can continue to monitor the air pressure value in the inner cavity of the underground salt mine.

[0067] In some embodiments, the system further comprises a switching device having at least six ports, wherein the first port is in communication with the ground opening of the annular cavity, the second port is in communication with the ground opening of the inner tube cavity, the third port is used to communicate with the gas compressor, the fourth port is used to communicate with the expander, the fifth port is used to communicate with the hot water pipe of the heating pipe, and the sixth port is used to communicate with the return water pipe of the heating pipe. The third port, the fourth port, the fifth port, and the sixth port can be switched to communicate with the first port and / or the second port.

[0068] For example, in Figure 2In the first working state of the occluder 30 shown, the second port of the switching device is communicated with the fifth port, and the first port is communicated with the sixth port.

[0069] For example, in Figure 3 In the second state of the occluder 30 shown, the first port of the switching device is communicated with the third port.

[0070] For example, in Figure 4 In the second state of the occluder 30, the first port of the switching device is connected to the fourth port.

[0071] For example, in Figure 5 In the second state of the occluder 30, the second port of the switching device is connected to the third port.

[0072] For example, in Figure 6 In the second state of the occluder 30, the second port of the switching device is connected to the fourth port.

[0073] In addition, the switching device may have other switching states, which are not listed in this specification.

[0074] The above compressor and expander may be the compressor and expander in the compressed air energy storage system in the prior art. For example, Figure 7 A schematic diagram of a compressed air energy storage system.

[0075] like Figure 7 As shown, under the compression energy storage condition, the air in the atmosphere alternately passes through the first to fourth stage compressors and the four intermediate heat exchangers on the compression side, and the high-pressure air is stored in the gas storage reservoir (i.e., the inner cavity of the underground salt mine), and the compression heat is stored in the high-temperature liquid storage tank after heat exchange with the air through the heat storage fluid; in this process, the regulating valves 1 to 4, the switch valve 1 and the switch valve 2 are in the open state, and the circulation pump 1 starts to run until the compression process is completed. Under the expansion energy release condition, the high-pressure air in the inner cavity of the underground salt mine alternately passes through the first to third stage expanders and the four intermediate heat exchangers on the expansion side, and the high-pressure gas in the inner cavity of the underground salt mine is gradually released and heated, and then enters the various stages of expanders to do work, driving the generator to release electrical energy; in this process, the regulating valves 5 to 7, the switch valve 1 and the switch valve 4 are in the open state, and the circulation pump 2 starts to run until the expansion process is completed. Among them, since the last-stage compressor in the compression process is operated with variable frequency, its exhaust temperature is lower than the exhaust temperature of the first three-stage compressors, and its compression heat level is low and cannot be recovered to the heat storage tank. Therefore, a circulating cooling water system is used to dissipate heat and cool it, or other forms of recovery and utilization of this part of the heat energy are used.

[0076] In a specific example, the comparison of the application conditions of various working conditions of the energy utilization system is shown in Table 1 below. This solution preferably retains only a salt cavern with one wellbore. A salt cavern contains two or more wellbores, and each wellbore can be designed and modified using this solution, but design priorities are required during application.

[0077] Table 1 Comparison of various working conditions of energy utilization system

[0078]

[0079] The design method of geothermal wells and well pipes in the energy utilization system combining underground salt mines and vertical shafts must simultaneously consider the design dimensions and material selection of the inner and outer pipes when air and water are used as working fluids flowing in the pipes. Since the gas storage only stores the pressure potential energy of air but not the thermal energy of air, when the compressed air energy storage utilization mode is adopted, only the resistance loss of air circulation is considered and its heat transfer loss is ignored. When the geothermal energy development and utilization mode is adopted, it is necessary to simultaneously consider the resistance loss, heat dissipation, and stress of water, so as to select the best well pipe design dimensions and structure.

[0080] The resistance loss can be further divided into the resistance loss along the way and the local resistance loss. The total resistance loss, including the air and water resistance loss along the way, is calculated by the following formula:

[0081]

[0082]

[0083] Where: Δp 1air is the air resistance loss along the way, Δp 1water is the water resistance loss along the way, l is the pipe length, mm; d is the pipe diameter, mm; ρ is the density of the heat medium, kg / m3; u is the flow rate of the heat medium, m / s; f c is the friction coefficient, and the specific expression is

[0084]

[0085] Where: ε is the roughness of the pipe wall, mm; Re is the Reynolds number, which can be calculated from parameters such as the internal working fluid flow rate, pipe diameter, density and viscosity of the well pipe.

[0086] In addition to the resistance loss along the way, the local resistance loss is mainly the energy loss of the reducer, where the diameter change mainly occurs in the wellbore, plug, pump and pump room and other equipment or components, because their geometric structure can cause the flow area to change. According to the actual local resistance loss type, after the local resistance coefficient ξ of different losses is given, the calculation formula of the local resistance loss of air and water is as follows:

[0087]

[0088]

[0089] The calculation formula for the total resistance loss of air and water is as follows, where the resistance loss of air is measured by pressure loss, in Pascals (Pa); the resistance loss of water is measured by head loss, in (m).

[0090] Δp air =Δp 1air +Δp 2air

[0091] Δp water =Δp 1water +Δp 2water

[0092] According to the above formula, for a given pipe diameter, the pressure losses of water and air are calculated at the same time, the pressure loss coefficients of water and air are given respectively, and the design is carried out with the minimum total pressure loss as the goal to select the optimal pipe diameter.

[0093] After determining the optimal pipe diameter, it is necessary to select the appropriate inner pipe material and wall thickness. Through systematic geothermal well and salt cavern stability analysis, comprehensive pressure drop, heat dissipation, stress and other factors, the selected pipe material, wall thickness and structure must meet the stress and insulation requirements under operating conditions.

[0094] The energy utilization system combining underground salt mines and vertical shafts can develop and utilize geothermal energy by using only plugs, without affecting the normal operation of compressed gas energy storage, and utilizing the time interval between gas storage and gas release, thus realizing an efficient and intensive utilization mode of "vertical shaft heat exchange + underground salt mine gas storage". In this mode, geothermal energy can be directly developed without the need for additional drilling, saving the expensive cost of vertical shaft drilling.

[0095] Due to the low thermal conductivity of rock formations and slow heat recovery, geothermal energy development has the characteristic of attenuation, which is manifested in the continuous decrease of outlet water temperature. For this, an alternating operation mode of "underground salt mine gas storage + geothermal energy development + underground salt mine gas release + geothermal energy development" can be adopted, which can allow geothermal energy to be temporarily restored and replenished during the gas storage and gas release periods to meet the sustainability of geothermal energy development and utilization. This underground salt mine utilization model combines the characteristics of the two systems of geothermal energy development and compressed gas energy storage, improves energy utilization efficiency while reducing system costs, and provides an efficient, innovative, clean and friendly "energy storage + heat extraction" energy application model.

[0096] This specification provides a control method for an energy utilization system combining an underground salt mine and a vertical shaft, which can be used in any of the above energy utilization systems. Figure 8 As shown, the control method includes S10 and S20.

[0097] S10: Before the gas is compressed to store energy or expanded to release energy, the plugging device is controlled to switch to the second state.

[0098] S20: After the gas compression energy storage or gas expansion energy release working condition ends, the plugging device is controlled to switch to the first state, and the heat medium in the heating system is controlled to flow through the annular cavity and the inner cavity of the inner tube.

[0099] "Controlling the heat medium in the heating system to flow through the annular cavity and the inner cavity of the inner tube" means that the energy utilization system operates in geothermal energy development mode, "gas compression energy storage working condition" means that the energy utilization system operates in underground salt mine gas storage mode, and "gas expansion energy release working condition" means that the energy utilization system operates in underground salt mine degassing mode.

[0100] In some embodiments, the energy utilization system can be controlled to adopt an alternating operation mode of "underground salt mine gas storage-geothermal energy development-underground salt mine gas release-geothermal energy development", so that geothermal energy can be briefly restored during the gas storage and gas release periods to meet the continuity of geothermal energy development.

[0101] In some embodiments, Fig. 9 As shown, S20 includes the following S21 to S23.

[0102] S21: After the gas compression energy storage or gas expansion energy release working condition ends, the plugging device is controlled to switch to the first state.

[0103] S22: Controlling to reduce the air pressure in the annular cavity and obtaining the air pressure value in the inner cavity of the underground salt mine.

[0104] S23: When the air pressure value is kept constant and the duration of the maintenance reaches a predetermined time threshold, the heat medium in the heating system is controlled to flow through the annular cavity and the inner cavity of the inner tube.

[0105] In some embodiments, Fig. 9 As shown, the control method further includes S30 to S50.

[0106] S30: Under the working condition of gas compression energy storage, obtaining the gas pressure value in the inner cavity of the underground salt mine.

[0107] S40: After the gas pressure value reaches a preset upper pressure limit, controlling to end the gas compression energy storage condition.

[0108] S50: When the occluder is in the second state, after receiving a deflation instruction, controlling the operation condition of starting gas expansion and energy release.

[0109] When the energy utilization system includes the above-mentioned switching device, controlling the heat medium in the heating system to flow through the annular cavity and the inner cavity of the inner tube includes: controlling the second port of the switching device to be connected to the fifth port, and the first port to be connected to the sixth port.

[0110] When the energy utilization system includes the above-mentioned switching device, before the energy utilization system operates in the gas compression energy storage condition, the third port of the switching device is controlled to be connected to the first port, or the third port of the switching device is controlled to be connected to the second port.

[0111] In the case where the energy utilization system includes the above-mentioned switching device, before the energy utilization system operates in the gas expansion energy release condition, the fourth port of the switching device is controlled to be connected to the first port, or the fourth port of the switching device is controlled to be connected to the second port.

[0112] The description and functions of the above control method can be understood by referring to the control system part of the energy utilization system combining underground salt mine and vertical shaft, and will not be repeated here.

[0113] The embodiment of the present invention further provides a controller, such as Fig.10 As shown, the controller may include a processor 1001 and a memory 1002, wherein the processor 1001 and the memory 1002 may be connected via a bus or other means. Fig.10 The example of connecting through bus is taken in the following.

[0114] The processor 1001 may be a central processing unit (CPU). The processor 1001 may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination of the above chips.

[0115] The memory 1002, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer executable programs and modules, such as program instructions / modules corresponding to the control method of the energy utilization system combining underground salt mines and shafts in the embodiment of the present invention. The processor 1001 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions and modules stored in the memory 1002, that is, the control method of the energy utilization system combining underground salt mines and shafts in the above method embodiment is realized.

[0116] The memory 1002 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required by at least one function; the data storage area may store data created by the processor 1001, etc. In addition, the memory 1002 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 1002 may optionally include a memory remotely arranged relative to the processor 1001, and these remote memories may be connected to the processor 1001 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0117] The one or more modules are stored in the memory 1002, and when executed by the processor 1001, the following is performed: Figure 1 The control method of the energy utilization system combining an underground salt mine and a vertical shaft in the illustrated embodiment.

[0118] The specific details of the above-mentioned controller can be understood by referring to the corresponding related descriptions and effects in the method embodiment, and will not be repeated here.

[0119] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD), etc.; the storage medium can also include a combination of the above-mentioned types of memory.

[0120] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0121] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions.

[0122] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0123] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute certain parts of the methods of each implementation method of the present application.

[0124] The present application can be used in many general or special computer system environments or configurations, such as personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc.

[0125] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0126] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and variations to the present application without departing from the spirit of the present application, and it is intended that the appended claims include these modifications and variations without departing from the spirit of the present application.

Claims

1. An energy utilization system combining an underground salt mine and a vertical shaft, characterized in that: include: An outer pipe, used to be arranged on the inner side of the shaft wall, the outer pipe being communicated with the inner cavity of the underground salt mine; An inner tube is used to be sleeved inside the outer tube; an annular cavity is formed between the outer tube and the inner tube; An occluder is arranged inside the outer tube and located at the bottom of the inner tube; wherein the occluder has a first state and a second state; In the first state, the plugger divides the inner cavity of the outer tube into upper and lower parts that are isolated from each other. In the upper part of the inner cavity of the outer tube, the annular cavity is connected with the inner cavity of the inner tube to form a part of the heat medium circulation path in the heating system; In the second state, the plugger blocks the bottom of the inner tube or the annular cavity so that the inner tube and / or the annular cavity are connected to the inner cavity of the underground salt mine through the bottom of the outer tube to form a gas flow channel, which is used to circulate compressed gas.

2. The energy utilization system according to claim 1, characterized in that: In the second state, the plugging device blocks the annular cavity and enables the inner cavity of the inner tube to communicate with the inner cavity of the underground salt mine; And / or, in the second state, the plugger blocks the bottom of the inner tube and enables the annular cavity to communicate with the inner cavity of the underground salt mine.

3. The energy utilization system according to claim 1, characterized in that: In the second state, the occluder is used to adjust the opening of the inner tube lumen and / or the annular cavity.

4. The energy utilization system according to claim 1, characterized in that: The plugging device is provided with a pressure detection device, and the pressure detection device is used to detect the air pressure value in the inner cavity of the underground salt mine.

5. The energy utilization system according to claim 1, characterized in that: The energy utilization system also includes: A switching device having at least six ports, wherein the first port is communicated with the ground opening of the annular cavity, the second port is communicated with the ground opening of the inner cavity of the inner tube, the third port is used to communicate with the gas compressor, the fourth port is used to communicate with the expander, the fifth port is used to communicate with the hot water pipe of the heating pipe, and the sixth port is used to communicate with the return water pipe of the heating pipe; The third port, the fourth port, the fifth port, and the sixth port are switched to communicate with the first port and / or the second port.

6. A control method for an energy utilization system combining an underground salt mine and a vertical shaft, characterized in that: Used for the energy utilization system according to any one of claims 1 to 5; the control method comprises: Before the working condition of gas compression energy storage or gas expansion energy release, controlling the plugging device to switch to the second state; After the gas compression energy storage or gas expansion energy release working condition ends, the plugging device is controlled to switch to the first state, and the heat medium in the heating system is controlled to flow through the annular cavity and the inner cavity of the inner tube.

7. The control method according to claim 6, characterized in that: After controlling the occluder to switch to the first state and before controlling the heat medium to flow through the annular cavity and the inner cavity of the inner tube, the method further includes: Controlling to reduce the air pressure in the annular cavity and obtaining the air pressure value in the inner cavity of the underground salt mine; When the air pressure value is kept constant and the duration of the maintenance reaches a predetermined time threshold, the heat medium in the heating system is controlled to flow through the annular cavity and the inner cavity of the inner tube.

8. The control method according to claim 6, characterized in that: The control method further comprises: Under the condition of gas compression energy storage, the gas pressure value in the inner cavity of the underground salt mine is obtained; After the gas pressure value reaches a preset upper pressure limit, controlling to end the gas compression energy storage working condition; and / or, When the occluder is in the second state, after receiving the deflation instruction, the operating condition of starting the gas expansion and energy release is controlled.

9. The control method according to claim 6, characterized in that: The energy utilization system also includes: A switching device having at least six ports, wherein the first port is communicated with the ground opening of the annular cavity, the second port is communicated with the ground opening of the inner cavity of the inner tube, the third port is used to communicate with the gas compressor, the fourth port is used to communicate with the expander, the fifth port is used to communicate with the hot water pipe of the heating pipe, and the sixth port is used to communicate with the return water pipe of the heating pipe; The third port, the fourth port, the fifth port, and the sixth port are switched to be connected to the first port and / or the second port; Accordingly, controlling the heat medium in the heating system to flow through the annular cavity and the inner cavity of the inner tube includes: controlling the second port of the switching device to communicate with the fifth port, and the first port to communicate with the sixth port; Before the energy utilization system operates in the gas compression energy storage condition, the third port of the control switching device is connected to the first port, or the third port of the control switching device is connected to the second port; Before the energy utilization system operates in the gas expansion energy release condition, the fourth port of the control switching device is connected to the first port, or the fourth port of the control switching device is connected to the second port.

10. A controller, characterized in that: Used to perform the method according to any one of claims 6 to 9.

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