Fused salt energy storage and gas energy supply coupling system

Abstract

The invention relates to the technical field of gas energy supply systems, and discloses a molten salt energy storage gas energy supply coupling system which comprises a molten salt circulation subsystem, a gas energy supply coupling system and a gas energy supply coupling system, and the molten salt circulation subsystem internally comprises a high-temperature molten salt storage part, an energy release heat exchanger, a low-temperature molten salt storage part and an energy storage heat exchanger which are sequentially and circularly communicated through a molten salt pipeline; the energy storage subsystem comprises a gas turbine and an oxidation furnace, a fuel inlet of the gas turbine is communicated with the gas extraction channel, and the inlet end of the oxidation furnace is communicated with the ventilation air methane channel; the energy release subsystem comprises a steam turbine, and a steam inlet of the steam turbine communicates with the cold side of the energy release heat exchanger. Through deep coupling of the molten salt circulation subsystem, the gas energy storage subsystem and the steam energy release subsystem, a clean energy system for coal mine gas all-component gradient utilization and multi-energy combined supply is constructed. Two low-concentration gases, namely ventilation air methane and extraction gas, are completely absorbed through the fused salt energy storage module, so that complete utilization of coal mine low-concentration gas resource is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of gas energy supply systems, and in particular to a molten salt energy storage and gas energy supply coupling system. Background Art

[0002] With the acceleration of the global industrialization process, energy demand continues to grow, and environmental problems are becoming increasingly prominent. As an important energy source, the treatment and utilization of low-concentration gas with a methane concentration of less than 30% generated in the production process of coal mines needs to be solved urgently. Low-concentration gas mainly includes extraction gas and mine ventilation gas (also known as ventilation gas). The amount of gas is huge, but due to the low methane concentration, traditional utilization methods are limited, there are problems such as explosion danger and low calorific value, and it is difficult to utilize.

[0003] The effective utilization of low-concentration gas has always been the focus of the development of coal mine gas utilization technology. In the existing technology, some solutions use the high-temperature flue gas generated by gas thermal storage oxidation to distribute heat, and use molten salt for heat storage and heating, but these technologies are often limited to the development of low-concentration gas thermal storage oxidation devices. The output of low-concentration gas in the coal mine production process is huge, and it is difficult to consume a large amount of low-concentration gas only through oxidation thermal storage. Summary of the invention

[0004] In view of this, the present invention provides a molten salt energy storage gas energy supply coupling system to solve the problem in the prior art that a large amount of low-concentration gas generated in the coal mine production process is difficult to be fully utilized.

[0005] In a first aspect, the present invention provides a molten salt energy storage and gas energy supply coupling system, comprising:

[0006] A molten salt circulation subsystem, which includes a high-temperature molten salt storage component, an energy-releasing heat exchanger, a low-temperature molten salt storage component and an energy-storing heat exchanger that are sequentially circulated and connected through a molten salt pipeline, wherein the hot side of the energy-releasing heat exchanger is installed on the molten salt pipeline, and the cold side of the energy-storing heat exchanger is installed on the molten salt pipeline;

[0007] An energy storage subsystem, comprising a gas turbine and an oxidation furnace, wherein the fuel inlet of the gas turbine is connected to the extraction gas channel, the inlet end of the oxidation furnace is connected to the exhaust gas channel, and the flue gas outlet of the gas turbine and the outlet end of the oxidation furnace are both connected to the hot side of the energy storage heat exchanger;

[0008] The energy releasing subsystem comprises a steam turbine, wherein the steam inlet of the steam turbine is connected to the cold side of the energy releasing heat exchanger.

[0009] The molten salt energy storage gas energy supply coupling system provided by the present invention is deeply coupled with the molten salt circulation subsystem, the gas energy storage subsystem and the steam energy release subsystem to construct a clean energy system for the cascade utilization of all components of coal mine gas and multi-energy co-supply. In the energy storage stage, the extracted gas generates high-temperature flue gas through the gas turbine for power generation, and the exhaust gas is oxidized by the oxidation furnace to generate high-temperature flue gas; the two high-temperature flue gases merge into the energy storage heat exchanger, transfer the heat to the molten salt circulation subsystem, and the heated molten salt is stored in the high-temperature storage component; in the energy release stage, when the high-temperature molten salt flows through the energy release heat exchanger, it transfers the heat to the steam turbine steam circuit to drive power generation, and the cooled molten salt returns to the low-temperature storage component; the low-temperature flue gas after energy release generates hot water through the waste heat recovery device, and outputs the wellbore insulation hot air through the air heat exchanger in winter. Moreover, through the coupling utilization of exhaust gas and extracted gas, when the oxidation furnace fails, the gas turbine flue gas can independently maintain the molten salt heating, while cutting off the exhaust gas channel, and shutting down the oxidation furnace for maintenance. By completely absorbing two types of low-concentration gas, namely exhaust gas and extraction gas, through molten salt energy storage modules, the full utilization of low-concentration gas resources in coal mines can be achieved, which can greatly improve resource utilization and avoid the direct emission of low-concentration gas that affects the environment.

[0010] In an optional embodiment, the cold side input end of the energy-releasing heat exchanger is connected to a water supply pipeline, and the water supply pipeline is connected to a heat exchange branch, and the cold side of the low-temperature heat exchanger is installed on the heat exchange branch, and the hot side of the energy-releasing heat exchanger is connected to the hot side of the low-temperature heat exchanger. The water supply pipeline provides water to the energy-releasing heat exchanger, and the water supply enters the cold side of the energy-releasing heat exchanger and absorbs the heat transferred from the energy-releasing heat exchanger, thereby generating steam to drive the steam turbine to operate. Part of the water supply enters the cold side of the low-temperature heat exchanger through the heat exchange branch, and exchanges heat with the heat transferred from the hot side of the energy-releasing heat exchanger. After absorbing heat, the temperature rises. This part of hot water can be used for low-temperature load needs such as bathing and domestic hot water in coal mines.

[0011] In an optional embodiment, the heat exchange branch downstream of the low-temperature heat exchanger is connected to a refrigeration branch, and a refrigeration device is installed on the refrigeration branch. The heat exchange branch downstream of the low-temperature heat exchanger is connected to a refrigeration branch, and the refrigeration device is installed on the refrigeration branch. After the low-temperature flue gas after heat exchange passes through the low-temperature heat exchanger to generate hot water, part of the heat is transferred to the refrigeration device through the heat exchange branch. The refrigeration device uses this part of the heat for refrigeration, and the generated cold can be used for the cooling load of the coal mine, such as cooling of buildings in summer. By adding refrigeration branches and refrigeration equipment, further utilization of the waste heat of the low-temperature flue gas is achieved, the comprehensive utilization efficiency of energy is improved, the cooling demand of the coal mine in summer is met, the cooling energy consumption is reduced, and the cascade utilization of energy is achieved.

[0012] In an optional embodiment, an auxiliary heat exchanger is further installed between the energy-releasing heat exchanger and the low-temperature molten salt storage element, and the hot side of the auxiliary heat exchanger is connected to the molten salt pipeline, and the cold side of the auxiliary heat exchanger is connected to the first air pipeline. When the molten salt flows from the energy-releasing heat exchanger to the low-temperature molten salt storage element, part of the heat is transferred to the air in the first air pipeline through the auxiliary heat exchanger, and the heated air can be used for the hot air demand of the coal mine, such as wellbore insulation in winter, coal slime drying, etc. By adding an auxiliary heat exchanger, the waste heat of the molten salt is further recovered, the energy utilization efficiency is improved, the coal mine's demand for hot air is met, the heating energy consumption is reduced, and the system's comprehensive energy utilization capacity is enhanced.

[0013] In an optional embodiment, a steam heat exchanger is further included, the hot side of the steam heat exchanger is connected to the steam outlet end of the steam turbine, and the cold side of the steam heat exchanger is connected to the second air pipeline. The steam exhausted by the steam turbine enters the steam heat exchanger and transfers the heat to the air in the second air pipeline. The heated air can be used for the hot air demand of the coal mine, such as winter shaft insulation and coal slime drying. By adding a steam heat exchanger, the waste heat of the steam turbine exhaust is fully utilized, the energy utilization efficiency is improved, the coal mine's demand for hot air is met, the heating energy consumption is reduced, and the system's comprehensive energy utilization capacity is enhanced.

[0014] In an optional embodiment, a mixer is installed upstream of the oxidation furnace, and a drainage gas branch is connected between the mixer and the drainage gas channel. The drainage gas enters the mixer through the drainage gas branch, mixes with the exhaust gas, and then enters the oxidation furnace for oxidation reaction. By adding a mixer and a drainage gas branch, the mixing of the drainage gas and the exhaust gas is achieved, the combustion efficiency and thermal energy utilization rate of the oxidation furnace are improved, the stable operation of the system is ensured, and at the same time, the low-concentration gas resources are fully utilized and the gas emission is reduced.

[0015] In an optional embodiment, the gas turbine and the steam turbine are both coaxially mounted with power generation equipment, and the power generation equipment is both conductively connected to the power grid. The coaxial power generation equipment converts mechanical energy into electrical energy, and part of the generated electricity meets the power demand of the mining area, and the excess power is connected to the grid for external transmission. By coaxially mounting power generation equipment on the gas turbine and the steam turbine, cogeneration of heat and power is achieved, energy utilization efficiency is improved, the power demand of the mining area is met, and dependence on the external power grid is reduced. At the same time, the excess power can be connected to the grid for external transmission, which increases economic benefits.

[0016] In an optional embodiment, a water supply pump is installed on the water supply pipeline, and the water supply pump is arranged upstream of the heat exchange branch. The water supply pump transports water from the water source to the heat exchange branch to ensure that there is sufficient water flow in the heat exchange branch to meet the heat exchange demand. By installing a water supply pump on the water supply pipeline and ensuring a stable water flow in the heat exchange branch, the heat exchange efficiency can be improved and the normal operation of the system can be ensured. At the same time, the setting of the water supply pump can also improve the flexibility and reliability of system regulation.

[0017] In an optional embodiment, a hot salt pump is installed downstream of the high-temperature molten salt storage component; and / or a cold salt pump is installed upstream of the low-temperature molten salt storage component. The hot salt pump transports the molten salt in the high-temperature molten salt storage component to the energy-releasing heat exchanger, and the cold salt pump transports the molten salt output from the energy-releasing heat exchanger to the low-temperature molten salt storage component. By installing a hot salt pump and a cold salt pump, the circulation of the molten salt in the system is ensured, which improves the operating efficiency and stability of the system. At the same time, the setting of the hot salt pump and the cold salt pump improves the flexibility and reliability of the system to meet the needs under different working conditions.

[0018] In an optional embodiment, at least two groups of hot salt pumps are arranged in parallel; and / or at least two groups of cold salt pumps are arranged in parallel. When one group of hot salt pumps or cold salt pumps fails, the other group can continue to work, ensuring the normal operation of the system, reducing the system downtime, and improving the continuous operation capability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] Figure 1 A schematic diagram of a molten salt energy storage and gas energy supply coupling system provided for an embodiment of the present invention.

[0021] Explanation of the accompanying drawings: 1. High-temperature molten salt storage component; 2. Energy-releasing heat exchanger; 3. Low-temperature molten salt storage component; 4. Energy-storage heat exchanger; 5. Gas turbine; 6. Oxidation furnace; 7. Steam turbine; 8. Low-temperature heat exchanger; 9. Refrigeration equipment; 10. Auxiliary heat exchanger; 11. Steam heat exchanger; 12. Mixer; 13. Feed water pump; 14. Hot salt pump; 15. Cold salt pump. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] Combine the following Figure 1 , describing an embodiment of the present invention.

[0024] According to an embodiment of the present invention, on the one hand, a molten salt energy storage and gas energy supply coupling system is provided, including a molten salt circulation subsystem, an energy storage subsystem and an energy release subsystem.

[0025] Among them, the molten salt circulation subsystem realizes the circulation connection of each component through the molten salt pipeline, specifically including the high-temperature molten salt storage component 1, the energy release heat exchanger 2, the low-temperature molten salt storage component 3 and the energy storage heat exchanger 4. Among them, the hot side of the energy release heat exchanger 2 is installed on the molten salt pipeline, and the cold side of the energy storage heat exchanger 4 is also installed on the molten salt pipeline to ensure the heat exchange and storage of the molten salt during the circulation process. The energy storage subsystem includes a gas turbine 5 and an oxidation furnace 6. The fuel inlet of the gas turbine 5 is connected to the extraction gas channel, and the extraction gas can be burned as fuel to generate high-temperature flue gas, and the inlet end of the oxidation furnace 6 is connected to the exhaust gas channel, and the exhaust gas is oxidized to generate high-temperature flue gas. The flue gas outlet of the gas turbine 5 and the outlet end of the oxidation furnace 6 are both connected to the hot side of the energy storage heat exchanger 4, so that the heat carried by the two high-temperature flue gases can be effectively transferred to the molten salt in the energy storage heat exchanger 4 to achieve heat storage. The energy release subsystem is provided with a steam turbine 7, and the steam inlet of the steam turbine 7 is connected to the cold side of the energy release heat exchanger 2. When the high-temperature molten salt flows through the energy release heat exchanger 2, the stored heat is transferred to the steam circuit of the steam turbine 7, driving the steam turbine 7 to generate electricity, thereby releasing the stored energy and completing the energy conversion and utilization.

[0026] The molten salt energy storage gas energy supply coupling system realizes the cascade utilization and multi-energy supply of all components of coal mine gas through the deep coupling and coordinated work of the three subsystems of molten salt circulation subsystem, energy storage subsystem and energy release subsystem, forming an efficient clean energy system. In the energy storage stage, the extracted gas is burned by the gas turbine 5 to generate high-temperature flue gas, and the exhaust gas is oxidized by the oxidation furnace 6 to generate high-temperature flue gas. These two high-temperature flue gases merge into the energy storage heat exchanger 4, which transfers heat to the molten salt in the molten salt circulation subsystem. The heated molten salt is stored in the high-temperature molten salt storage part 1, completing the energy storage process; in the energy release stage, the high-temperature molten salt flows out from the high-temperature molten salt storage part 1, and when it flows through the energy release heat exchanger 2, it transfers the stored heat to the steam circuit of the steam turbine 7, drives the steam turbine 7 to generate electricity, realizes the release and conversion of energy, and the cooled molten salt returns to the low-temperature molten salt storage part 3, waiting for the next recycling. In addition, the low-temperature flue gas after energy release can also generate hot water through the waste heat recovery device, and output the wellbore insulation hot air through the air heat exchanger in winter, further improving the energy utilization efficiency. Moreover, the system has high stability and reliability through the coupling utilization design of exhaust gas and extraction gas. When the oxidation furnace 6 fails, the flue gas generated by the gas turbine 5 can independently maintain the heating process of the molten salt. At this time, the exhaust gas channel can be cut off, and the oxidation furnace 6 can be shut down for maintenance to ensure the normal operation of the system. Through the molten salt energy storage module, the two low-concentration gases, exhaust gas and extraction gas, can be fully absorbed, realizing the full utilization of low-concentration gas resources in coal mines, which not only greatly improves the resource utilization rate, but also effectively avoids the adverse effects of direct emissions of low-concentration gas on the environment.

[0027] In one embodiment, the cold side input end of the energy releasing heat exchanger is connected to the water supply pipeline, and a heat exchange branch is branched from the water supply pipeline. The cold side of the low temperature heat exchanger 8 is installed on the heat exchange branch, and the hot side of the energy releasing heat exchanger 2 is connected to the hot side of the low temperature heat exchanger 8. The water supply pipeline provides water to the energy releasing heat exchanger. After the water enters the cold side of the energy releasing heat exchanger, it absorbs the heat transferred from the energy releasing heat exchanger 2, thereby generating steam to drive the steam turbine 7 to operate. As an alternative embodiment, a preheating device can be set between the energy releasing heat exchanger and the water supply pipeline to preheat the water supply in advance, increase the temperature of the water supply when entering the energy releasing heat exchanger, further improve the steam generation efficiency, and improve the operation efficiency of the steam turbine 7. Part of the cooling water enters the cold side of the low temperature heat exchanger 8 through the heat exchange branch, exchanges heat with the heat transferred from the hot side of the energy releasing heat exchanger 2, and the temperature rises after absorbing heat. This part of hot water can be used for low temperature loads such as bathing and domestic hot water in coal mines.

[0028] Furthermore, the heat exchange branch downstream of the low-temperature heat exchanger 8 is connected to a refrigeration branch, and a lithium bromide unit as a refrigeration device 9 is installed on the refrigeration branch. After the low-temperature flue gas after heat exchange passes through the low-temperature heat exchanger 8 to generate hot water, there is still some residual heat, which is transferred to the refrigeration device 9 through the heat exchange branch. The refrigeration device 9 uses this part of heat for refrigeration, and the generated cold can be used for the cooling load of the coal mine, such as summer building cooling. By adding the refrigeration branch and the refrigeration device 9, the deep utilization of the residual heat of the low-temperature flue gas is realized, the comprehensive utilization efficiency of energy is improved, the cooling demand of the coal mine in summer is met, the refrigeration energy consumption is reduced, and the cascade utilization of energy is realized.

[0029] In one embodiment, an auxiliary heat exchanger 10 is installed between the energy-releasing heat exchanger 2 and the low-temperature molten salt storage unit 3, and the hot side of the auxiliary heat exchanger 10 is connected to the molten salt pipeline, and the cold side is connected to the first air pipeline. When the molten salt flows from the energy-releasing heat exchanger 2 to the low-temperature molten salt storage unit 3, part of the heat is transferred to the air in the first air pipeline through the auxiliary heat exchanger 10, and the heated air can be used for the hot air needs of the coal mine, such as winter shaft insulation, coal slime drying, etc. By adding the auxiliary heat exchanger 10, the waste heat of the molten salt is further recovered, the energy utilization efficiency is improved, the coal mine's demand for hot air is met, the heating energy consumption is reduced, and the system's comprehensive energy utilization capacity is enhanced. In some other embodiments, an air preheating device can be set between the cold side of the auxiliary heat exchanger 10 and the first air pipeline to preheat the air in advance, increase the temperature of the air when it enters the auxiliary heat exchanger 10, and improve the heat exchange effect and hot air output.

[0030] In this embodiment, the molten salt energy storage gas energy supply coupling system also includes a steam heat exchanger 11, the hot side of the steam heat exchanger 11 is connected to the steam outlet end of the steam turbine 7, and the cold side is connected to the second air pipeline. The steam exhausted by the steam turbine 7 enters the steam heat exchanger 11, and transfers the heat to the air in the second air pipeline. The heated air can be used for the hot air demand of the coal mine, such as winter shaft insulation, coal slime drying, etc. By adding the steam heat exchanger 11, the waste heat of the steam exhaust of the steam turbine 7 is fully utilized, the energy utilization efficiency is improved, the demand for hot air in the coal mine is met, the heating energy consumption is reduced, and the comprehensive energy utilization capacity of the system is enhanced. In some other embodiments, an air humidification device can be set between the cold side of the steam heat exchanger 11 and the second air pipeline to humidify the air so that the generated hot air has both a suitable temperature and a suitable humidity, which can better meet the needs of coal mines in different scenarios.

[0031] In one embodiment, a mixer 12 is installed upstream of the oxidation furnace 6, and a gas extraction branch is connected between the mixer 12 and the gas extraction channel. The extracted gas enters the mixer 12 through the gas extraction branch, and enters the oxidation furnace 6 for oxidation reaction after being mixed with the exhaust gas. By adding the mixer 12 and the gas extraction branch, the mixing of the extracted gas and the exhaust gas is achieved, the combustion efficiency and thermal energy utilization rate of the oxidation furnace 6 are improved, and the stable operation of the system is ensured. At the same time, low-concentration gas resources are fully utilized and gas emissions are reduced. In some other embodiments, a preheating device can be set between the mixer 12 and the oxidation furnace 6 to preheat the mixed gas gas, increase the temperature of the gas gas when it enters the oxidation furnace 6, and further improve the efficiency of the oxidation reaction and the thermal energy utilization rate.

[0032] In one embodiment, the gas turbine 5 and the steam turbine 7 are both coaxially installed with power generation equipment, and the power generation equipment is conductively connected to the power grid. The coaxial power generation equipment converts mechanical energy into electrical energy, and a part of the generated electricity meets the power demand of the mining area, and the excess power is connected to the grid for external transmission. By coaxially installing the power generation equipment on the gas turbine 5 and the steam turbine 7, cogeneration of heat and power is achieved, the energy utilization efficiency is improved, the power demand of the mining area is met, and the dependence on the external power grid is reduced. At the same time, the excess power can be connected to the grid for external transmission, which increases economic benefits. As an alternative implementation method, an electric energy storage device can be set between the power generation equipment and the power grid to store excess electricity and release it during the peak power consumption of the mining area, so as to further improve the stability and reliability of the power supply, and at the same time, the load of the power grid can be better adjusted.

[0033] In one embodiment, a water supply pump 13 is installed on the water supply pipeline, and the water supply pump 13 is arranged upstream of the heat exchange branch. The water supply pump 13 transports water from the water source to the heat exchange branch to ensure that there is sufficient water flow in the heat exchange branch to meet the heat exchange demand. By installing the water supply pump 13 on the water supply pipeline and ensuring a stable water flow in the heat exchange branch, the heat exchange efficiency can be improved and the normal operation of the system can be ensured. At the same time, the setting of the water supply pump 13 can also improve the flexibility and reliability of system regulation. In some other embodiments, a flow regulating device can also be provided between the water supply pump 13 and the heat exchange branch to accurately adjust the water supply flow according to the actual heat exchange demand, thereby further improving the heat exchange efficiency and the stability of the system.

[0034] In one embodiment, a hot salt pump 14 is installed downstream of the high-temperature molten salt storage 1, and a cold salt pump 15 is installed upstream of the low-temperature molten salt storage 3. The hot salt pump 14 transports the molten salt in the high-temperature molten salt storage 1 to the energy-releasing heat exchanger 2, and the cold salt pump 15 transports the molten salt output from the energy-releasing heat exchanger 2 to the low-temperature molten salt storage 3. By installing the hot salt pump 14 and the cold salt pump 15, the circulation of the molten salt in the system is ensured, and the operating efficiency and stability of the system are improved. At the same time, the setting of the hot salt pump 14 and the cold salt pump 15 improves the flexibility and reliability of the system to meet the needs under different working conditions.

[0035] In one embodiment, at least two groups of hot salt pumps 14 are arranged in parallel and at least two groups of cold salt pumps 15 are arranged in parallel. In this embodiment, two groups of hot salt pumps 14 and cold salt pumps 15 are arranged in parallel. When one group of hot salt pumps 14 or cold salt pumps 15 fails, the other group can continue to work, ensuring the normal operation of the system, reducing the system downtime, and improving the continuous operation capacity of the system. An automatic switching device can be set between the hot salt pumps 14 or cold salt pumps 15 arranged in parallel. When one group of pumps fails, it automatically switches to another group of pumps to achieve seamless switching, further improving the stability and reliability of the system, and ensuring that the system can operate uninterruptedly for a long time.

[0036] When the molten salt energy storage gas energy supply coupling system provided in this embodiment is working, the extracted gas directly enters the gas turbine 5 for power generation in one way, and enters the thermal storage oxidation furnace 6 after being mixed with the exhaust gas in the other way. The high-temperature exhaust gas of the gas turbine 5 and the high-temperature flue gas of the oxidation furnace 6 are mixed and then enter the flue gas-molten salt heat exchanger as the energy storage heat exchanger 4 to heat the molten salt. The low-temperature flue gas after heat exchange generates hot water through the low-temperature heat exchanger 8, which is used for bathing and domestic hot water in coal mines, and the lithium bromide unit is used as a cooling load in summer.

[0037] The molten salt heated by the high-temperature flue gas flows into the high-temperature molten salt tank as a high-temperature molten salt storage component for heat storage. The molten salt in the high-temperature molten salt tank is pressurized by the hot salt pump 14 and then transported to the molten salt-steam heat exchanger 11 as the energy release heat exchanger 2 and the molten salt-air heat exchanger 10 as the auxiliary heat exchanger. The molten salt with reduced temperature finally flows into the low-temperature molten salt tank as the low-temperature heat exchanger 8 through the cold salt pump 15. The superheated steam generated by the steam heat exchanger 11 is used for power generation by the steam turbine 7, and the hot air generated by the exhaust heat exchange of the steam turbine 7 is combined with the hot air generated by the air heat exchanger to provide heat loads for wellbore insulation and coal slime drying in winter.

[0038] The electricity generated by the gas turbine 5 and the steam turbine 7 can meet the mine's own electricity needs, and the excess electricity can be connected to the grid and sent out. The high-temperature flue gas of the flue gas-molten salt heat exchanger comes from the high-temperature exhaust gas of the gas turbine 5 and the oxidation furnace 6 device. When the oxidation furnace 6 device fails, the control valve can be used to cut off the gas extraction and exhaust air pipeline of the mixer 12, and the mixed gas is discharged to the air through the pipeline emergency discharge valve. At this time, the high-temperature flue gas of the flue gas-molten salt heat exchanger comes from the flue gas discharged by the gas turbine 5, and the flue gas flow is controlled by the control valve. The molten salt uses a new type of nitrate composite material with a low melting point and high heat storage density. It has a low melting point and a high boiling point. It can overcome the problem that the molten salt has a low solidification point and is easy to freeze and block the pipeline, widen the energy storage temperature zone, reduce the amount of molten salt, and improve reliability.

[0039] Both high-temperature molten salt storage tanks and low-temperature molten salt storage tanks use vertical arched cold and hot double tanks. The tank bottom should be equipped with a ventilation cooling system, including ventilation fans, ventilation pipes, control valves, temperature monitoring points, etc. The tank top, tank wall and tank bottom are all insulated. The insulation materials of the tank wall and tank top, as well as the insulation materials in direct contact with the bottom of the tank, should be low-chloride ion materials to prevent corrosion on the outside of the tank.

[0040] Molten salt electric heaters are installed in both the high-temperature molten salt storage tank and the low-temperature molten salt storage tank. The electric heaters with high voltage level and high energy flow density are adopted. On the one hand, they can be used for seed molten salt salting. On the other hand, when the oxidation furnace 6 device fails or the flue gas volume is insufficient, the molten salt is heated to maintain the normal operation of the energy storage module. Both the cold salt pump 15 and the hot salt pump 14 adopt vertical submersible centrifugal pumps. The cold salt pump 15 and the hot salt pump 14 are configured as one-in-one or two-in-one redundant, and a frequency converter is provided. The flow rate of the molten salt can be controlled by the frequency converter. A salt scavenging tank should be provided at the low point of the pipeline of the molten salt energy storage module. Under accident conditions, the salt scavenging tank can collect the salt scavenging in the energy storage system through its own liquid level potential energy, and send it back to the low-temperature molten salt tank through the salt scavenging pump. The salt scavenging pump is configured as one-in-one redundant.

[0041] Molten salt pipelines and valves are heated by electricity. The heating of the electric heating belt is completed by the temperature controller in the control cabinet, which can be automatically adjusted according to the ambient temperature to meet the heat loss of equipment and pipelines at a specific temperature. The electric heating control should have a fault diagnosis function and automatically cut off the power supply of the heating circuit in the event of power failure, sensor failure, overtemperature or leakage.

[0042] The molten salt energy storage and gas energy supply coupling system provided in this embodiment achieves zero emission of coal mine gas, which is of great significance. By using high-temperature flue gas to heat the molten salt energy storage, the system is simple and has no phase change section. It can increase the temperature of the molten salt, which is conducive to temperature matching in the heat exchange process and reduces Loss. The existing abundant gas resources in coal mines are fully utilized, and with certain load devices, the coal mine can basically achieve self-sufficiency in energy consumption and meet the conditions for island operation. The molten salt energy storage gas energy supply coupling system provided in this embodiment realizes the energy cascade utilization of the coal mine comprehensive energy supply system. The high-temperature part meets the coal mine's self-use electricity load demand through the gas turbine 5 and the steam turbine 7; the medium-temperature part is used to meet the coal mine's winter shaft insulation and coal slime drying heat load; the low-temperature part meets the coal mine's bathing hot water load, building heating, and cooling load through the lithium bromide unit.

[0043] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A molten salt energy storage gas energy supply coupling system, characterized in that: include: A molten salt circulation subsystem, comprising a high-temperature molten salt storage element (1), an energy-releasing heat exchanger (2), a low-temperature molten salt storage element (3) and an energy-storing heat exchanger (4) which are sequentially circulated and connected via a molten salt pipeline, wherein the hot side of the energy-releasing heat exchanger (2) is mounted on the molten salt pipeline, and the cold side of the energy-storing heat exchanger (4) is mounted on the molten salt pipeline; An energy storage subsystem, comprising a gas turbine (5) and an oxidation furnace (6), wherein a fuel inlet of the gas turbine (5) is connected to a gas extraction channel, an inlet end of the oxidation furnace (6) is connected to a ventilation gas channel, and a flue gas outlet of the gas turbine (5) and an outlet end of the oxidation furnace are both connected to a hot side of the energy storage heat exchanger (4); The energy release subsystem comprises a steam turbine (7), wherein the steam inlet of the steam turbine (7) is connected to the cold side of the energy release heat exchanger (2).

2. The molten salt energy storage and gas energy supply coupling system according to claim 1 is characterized in that: The cold side input end of the energy-releasing heat exchanger is connected to a water supply pipeline, the water supply pipeline is connected to a heat exchange branch, the cold side of a low-temperature heat exchanger (8) is installed on the heat exchange branch, and the hot side of the energy-releasing heat exchanger (2) is connected to the hot side of the low-temperature heat exchanger (8).

3. The molten salt energy storage and gas energy supply coupling system according to claim 2 is characterized in that: The heat exchange branch downstream of the low-temperature heat exchanger (8) is connected to a refrigeration branch, and a refrigeration device (9) is installed on the refrigeration branch.

4. The molten salt energy storage and gas energy supply coupling system according to any one of claims 1 to 3, characterized in that: An auxiliary heat exchanger (10) is also installed between the energy-releasing heat exchanger (2) and the low-temperature molten salt storage element (3), the hot side of the auxiliary heat exchanger (10) is connected to the molten salt pipeline, and the cold side of the auxiliary heat exchanger (10) is connected to the first air pipeline.

5. The molten salt energy storage and gas energy supply coupling system according to any one of claims 1 to 3, characterized in that: It also comprises a steam heat exchanger (11), the hot side of the steam heat exchanger (11) being connected to the steam outlet end of the steam turbine (7), and the cold side of the steam heat exchanger (11) being connected to the second air pipeline.

6. The molten salt energy storage and gas energy supply coupling system according to any one of claims 1 to 3, characterized in that: A mixer (12) is installed upstream of the oxidation furnace (6), and a gas extraction branch is connected between the mixer (12) and the gas extraction channel.

7. The molten salt energy storage and gas energy supply coupling system according to any one of claims 1 to 3, characterized in that: The gas turbine (5) and the steam turbine (7) are both coaxially mounted with power generation equipment, and the power generation equipment is both conductively connected to the power grid.

8. The molten salt energy storage and gas energy supply coupling system according to claim 2 or 3, characterized in that: A water supply pump (13) is installed on the water supply pipeline, and the water supply pump (13) is arranged upstream of the heat exchange branch.

9. The molten salt energy storage and gas energy supply coupling system according to any one of claims 1 to 3, characterized in that: A hot salt pump (14) is installed downstream of the high-temperature molten salt storage element (1); and / or a cold salt pump (15) is installed upstream of the low-temperature molten salt storage element (3).

10. The molten salt energy storage and gas energy supply coupling system according to claim 9, characterized in that: At least two groups of the hot salt pumps (14) are arranged in parallel; and / or at least two groups of the cold salt pumps (15) are arranged in parallel.

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