CN115822912A - Hot-pressing decoupling liquid piston compressed air energy storage system and operation method thereof - Google Patents
Hot-pressing decoupling liquid piston compressed air energy storage system and operation method thereof Download PDFInfo
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Abstract
The invention discloses a hot-press decoupling liquid piston compressed air energy storage system and an operation method thereof, wherein the system comprises a compressed air energy storage unit, a heat exchange and heat storage unit and an expansion generator set; the variable compressed air system and the double-tank type near-isothermal compressed air system are respectively used as a low-pressure stage and a high-pressure stage of the energy storage side of the whole system to sequentially compress air, the compression ratio of a multi-stage compressor in the variable compressed system is adjusted, and the compression ratio of a water tank in the double-tank type near-isothermal compressed system is matched and adjusted to reach a target pressure, so that the compression heat generated by the compressed air in the energy storage process can be fully utilized in the energy release process, and the problem of unbalanced heat supply and demand in the energy storage and release process caused by the arrangement of a throttle valve at the inlet of an expander is solved; and the heat accumulator unit is used for storing the compression heat, and the flexibility of the compressed air energy storage unit is utilized to acquire and store pressure potential energy, so that the decoupling of the heat energy and the pressure potential energy is realized, and the heat energy required by releasing the pressure potential energy is efficiently distributed.
Description
Technical Field
The invention belongs to the technical field of physical energy storage, and particularly relates to a hot-pressing decoupling liquid piston compressed air energy storage system and an operation method thereof.
Background
With the rapid increase of the total installed capacity of new energy, the problem of instability and intermittence in the new energy power generation process is solved to be a main problem of large-scale utilization of the new energy, and energy storage is one of main solutions of the new energy. Energy storage is the storage of energy through some medium and the release of energy when needed. Compressed air energy storage and pumped storage are well known as systems suitable for high power and large capacity storage of hundreds of megawatts. Although the pumped storage power station has high efficiency, in the construction of a large pumped storage power station, the initial investment is huge, the construction period is long, the requirement on the constructed geographical position is very strict, the site selection is difficult, and vegetation and cities are even submerged; compared with pumped storage, compressed air storage is more flexible in site selection and lower in investment. In recent years, with the understanding and research on compressed air energy storage technology, several large compressed air energy storage power plants have been built.
Compressed air energy storage can be technically divided into non-adiabatic, adiabatic and isothermal. The traditional compressed air energy storage type is a non-adiabatic compressed air energy storage system with fuel combustion, the main components comprise a multi-stage compressor, an air storage device, a combustion chamber and a multi-stage turbo expander, when electricity is used in the valley, redundant valley electricity is used for driving a motor, the multi-stage compressor is driven by a coupler to compress air, and the generated high-pressure air is stored in the air storage device; during the peak of electricity utilization, high-pressure air is released from the air storage device, is mixed with fuel in the combustion chamber and then is combusted, and finally enters the multistage turboexpander to do work and generate electricity to be connected to a power grid; however, the disadvantages are that the multi-stage compressor compresses air to generate heat for dissipation, and fossil fuel is consumed to cause pollution when releasing energy.
The adiabatic compressed air energy storage refers to that on the basis of a traditional compressed air energy storage system heated by fuel, a combustion chamber and fuel heating are cancelled, a heat storage device and a heat exchanger are added, when air is compressed in an energy storage stage, the heat exchanger is arranged at the stage of a compressor or after the stage of the compressor, and a cold heat storage medium flowing in the heat exchanger absorbs compression heat generated in the compression process of the air and stores the heat in the heat storage device; in the energy releasing process, before the gas enters the expansion machine to do work, a heat exchanger is arranged in front of a stage or between stages, and the high-pressure air is heated by a heat storage medium flowing in the heat exchanger so as to utilize compression heat; the basic structure of a compressed air energy storage system is kept, and the combustion of fossil fuel is avoided; in the energy release stage, in order to stabilize the working condition of air entering the expander, a throttle valve needs to be arranged to obtain air flow with stable pressure, so that the pressure of the air before entering the expander for expansion is smaller than the storage pressure of the air, the heat generated in the air compression process is larger than the heat required by the air expansion, and the problem of imbalance of heat supply and demand in the energy storage and release processes is caused.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a hot-pressing decoupling liquid piston compressed air energy storage system and an operation method thereof, wherein the compression ratio of a multi-stage compressor in a variable compression system is adjusted, and the compression ratio of a double-tank type near-isothermal compression system is matched and adjusted to reach the target pressure, so that the compression heat generated by compressed air in the energy storage process can be fully utilized in the energy release process; the heat accumulator unit is used for storing compression heat generated in the air compression process of the multi-variable compressed air system, and the compressed air energy storage unit containing the multi-variable compressed air system and the double-tank type near-isothermal compressed air energy storage system is used for flexibly acquiring and storing pressure potential energy, so that the heat energy and the pressure potential energy are decoupled and combined to separately store the heat energy and the pressure potential energy, and the heat energy required by releasing the pressure potential energy is efficiently distributed.
In order to achieve the purpose, the invention adopts the technical scheme that: a hot-pressing decoupling liquid piston compressed air energy storage system comprises a changeable compressed air system, a double-tank type near-isothermal compressed air energy storage system, a heat exchange and heat storage unit and an expansion generator set; the changeable compressed air system comprises a multi-stage compressor, wherein the outlet of each stage of the compressor from low to high is provided with a heat exchange and heat storage unit, the gas outlet of the last stage of the heat exchange and heat storage unit is connected with the gas inlet of the double-tank type near-isothermal compressed air energy storage system, the compressor is connected with the hot side of the heat exchange and heat storage unit, the gas outlet of the double-tank type near-isothermal compressed air energy storage system is sequentially connected with a heat storage type gas storage tank, the expansion generator set comprises multi-stage expanders, and the working medium inlet of each stage of the expanders is connected with the cold side of the heat exchange and heat storage unit; the gas outlet of the heat accumulating type gas storage tank is connected with the gas inlet on the cold side of the heat exchange and heat accumulation unit of the inlet of the highest stage of expansion machine, the multi-stage compressor set is driven by the motor, and the expansion generator set is connected with the generator; the inlet of the double-tank type near-isothermal compressed air energy storage system is connected with a circulating water pump and an underground water tank.
The heat exchange and heat storage unit comprises a packed bed heat accumulator, a water cooler and a water heater, wherein a hot side inlet of the packed bed heat accumulator is connected with a compressor outlet, a hot side outlet of the packed bed heat accumulator is connected with a hot side inlet of the water cooler, and a hot side outlet of the water cooler is connected with a compressor inlet; a cold side inlet of the highest water heater is used as a gas inlet of the cold side of the heat exchange and heat storage unit, a cold side outlet of the water heater is connected with a cold side inlet of the packed bed heat storage device, and a cold side outlet of the packed bed heat storage device is connected with an expansion machine; the hot side of the water heater and the cold side of the water cooler are both connected with an underground water source or an underground water tank.
The multi-stage compressor set comprises a low-pressure compressor, a medium-pressure compressor and a high-pressure compressor which are arranged along the air flow direction, and the expansion generator set comprises inlets of a high-pressure expander, a medium-pressure expander and a low-pressure expander which are sequentially arranged along the air flow direction; hot side outlets of the first water cooler and the second water cooler are respectively communicated with inlets of a medium-pressure compressor and a high-pressure compressor, and a hot side outlet of the third water cooler is communicated with an air inlet of the double-tank type near-isothermal compressed air energy storage system and is used as a connecting section of the polytropic compression system and the near-isothermal compression system; outlets of the high-pressure expander and the medium-pressure expander are respectively communicated with cold side inlets of the second water heater and the third water heater, and an outlet of the heat accumulating type air storage tank is communicated with a cold side inlet of the first water heater.
The heat accumulating type gas storage tank adopts a vertical tank, 5-8 phase-change heat accumulating sheets with holes are horizontally and uniformly distributed in the heat accumulating type gas storage tank along the height direction, the phase-change heat accumulating sheets with holes are gradually bent and protruded from the edge to the middle, and the higher the height is, the larger the protrusion degree of the phase-change heat accumulating sheets with holes is; the bending radius of the phase-change type heat storage plate with the hole does not exceed the radius of a heat storage type gas storage tank body; one circle of the phase-change type heat storage sheet with the holes is welded on the peripheral pipe wall of the heat storage type gas storage tank.
Phase-change heat storage balls are distributed in the phase-change heat storage sheets with holes in the heat storage gas storage tank, and the balls are uniformly distributed in the phase-change heat storage sheets with holes and the number of the distributed layers is not more than that of the layers; the phase-change type heat storage plate with the holes is distributed with different numbers of vent holes along different radiuses, the vent hole interval is 1/2-2/3 of the vent hole diameter, and the number of vent holes in each circle is increased by 5-10 along the increasing direction of the radiuses.
The double-tank type near-isothermal compressed air energy storage system comprises a first high-pressure water tank and a second high-pressure water tank, wherein the first high-pressure water tank and the second high-pressure water tank are provided with two pipelines for communicating a water inlet and a water outlet, gas-liquid separators are arranged on the communication pipelines of the water inlets and the water outlets of the first high-pressure water tank and the second high-pressure water tank, and valves are arranged at the water inlets and the water outlets of the first high-pressure water tank and the second high-pressure water tank; the first high-pressure water tank and the second high-pressure water tank are both provided with a liquid level sensor, and the water inlets of the first high-pressure water tank and the second high-pressure water tank are communicated with the underground water tank through a water pump unit; the gas inlets of the first high-pressure water gas tank and the second high-pressure water gas tank are communicated with the gas outlet of the heat exchange and heat storage unit, the pipelines from the heat exchange and heat storage unit to the gas inlets of the first high-pressure water gas tank and the second high-pressure water gas tank are respectively provided with a valve, the gas outlets of the first high-pressure water gas tank and the second high-pressure water gas tank are communicated with the heat storage gas tank, and the pipelines from the gas outlets of the first high-pressure water gas tank and the second high-pressure water gas tank to the heat storage gas tank are respectively provided with a valve.
The electric energy output end of the generator is connected with a power grid and/or a motor for driving the multistage compressor and the water pump.
According to the operation method of the hot-press decoupling liquid piston compressed air energy storage system, water is supplemented to a set water level in the double-tank type near-isothermal compressed air energy storage unit in a preset stage;
when the system stores energy, air is compressed by the multistage compressors, the compressed air releases heat in the heat exchange and heat storage unit at the outlet of each stage of compressor, the compressed air enters the double-tank type near-isothermal compressed air energy storage system through the last stage heat exchange and heat storage unit and is compressed to a target pressure, and the air reaching the target pressure enters the heat storage type air storage tank for storing energy; pumping water from the underground water tank and pressurizing by the double-tank type near-isothermal compressed air energy storage system;
when the system releases energy, compressed air is released from the bottom of the heat storage type air storage tank, and the compressed air enters the expansion machine to do work after absorbing heat and raising the temperature of the heat exchange and heat storage unit at the working medium inlet of each stage of expansion unit to drive the generator to generate power.
The variable compressed air system is used as low-pressure-stage compressed air at the energy storage side of the whole system, the double-tank type near-isothermal compressed air system is used as high-pressure-stage compressed air at the energy storage side of the whole system, an outlet of the variable compressed air system is connected with an inlet of the double-tank type near-isothermal compressed air system, and the compression ratio of a water tank in the double-tank type near-isothermal compressed air system is matched and adjusted to reach the target pressure by adjusting the compression ratio of each stage of compressor in the variable compressed system, so that the compression heat generated by the compressed air in the energy storage process can be fully utilized in the energy release process; and the heat exchange and heat storage unit is used for storing the compression heat generated in the air compression process of the multivariable compressed air system.
5-8 phase-change heat storage sheets with holes are horizontally and uniformly distributed in the heat storage type gas storage tank along the height direction, and phase-change heat storage balls are distributed in the phase-change heat storage sheets with holes in the heat storage type gas storage tank; the air is compressed to a target pressure by the double-tank near-isothermal compressed air energy storage system and enters the heat storage air storage tank from the top, the air passes through the phase-change heat storage sheets with holes layer by layer and gradually fills the whole heat storage air storage tank, the near-isothermal compressed heat is stored in the phase-change heat storage balls in the phase-change heat storage sheets with holes, and the temperature of the contact air of the phase-change heat storage sheets with holes at the top layer is the highest, so that the absorbed heat is the most;
when the system releases energy, compressed air is released from the bottom of the heat accumulating type air storage tank, the expansion and cooling of the air in the heat accumulating type air storage tank and the phase change type heat accumulation sheet with the holes generate temperature difference, the phase change material in the phase change heat accumulation balls in the phase change type heat accumulation sheet with the holes changes the phase and releases heat, the air absorbs heat and heats up, and then the compressed air enters the expansion unit step by step after being subjected to pre-heat exchange by the heat exchange and heat accumulation unit.
The electricity generated by the generator can be used for a motor and a water pump unit which are integrated into a power grid and a compressor.
Compared with the prior art, the invention has at least the following beneficial effects:
in the energy storage process of the system, a polytropic compressed air system in a compressed air energy storage unit is used as low-pressure-stage compressed air at the energy storage side of the whole power generation system, a double-tank type near-isothermal compressed air system is used as high-pressure-stage compressed air at the energy storage side of the whole power generation system, an outlet of the polytropic compressed air system is connected with an inlet of the double-tank type near-isothermal compressed air system, and the compression ratios of a low-pressure compressor, a medium-pressure compressor and a high-pressure compressor in the polytropic compressed air system are adjusted and matched with the compression ratios of a first high-pressure water tank and a second high-pressure water tank in the double-tank type near-isothermal compressed air system to achieve target pressure, so that the compression heat generated by the compressed air in the energy storage process can be fully utilized in the energy release process, the heat loss of the system is avoided, and the system efficiency is improved; the heat accumulator unit is used for storing compression heat generated in the air compression process of the multi-variable compressed air system, and the compressed air energy storage unit including the multi-variable compressed air system and the double-tank type near-isothermal compressed air energy storage system is used for flexibly acquiring and storing pressure potential energy, so that the heat energy and the pressure potential energy are decoupled and combined to separately store the heat energy and the pressure potential energy, and the heat energy required by releasing the pressure potential energy is efficiently distributed.
Furthermore, the three water coolers use underground water or underground water tank water as a cold-side medium to cool the compressed air to normal temperature so as to reduce the working energy consumption of the low-pressure compressor, the medium-pressure compressor and the high-pressure compressor; the three water heaters preheat the air at the outlet of the heat accumulating type air storage tank, the high-pressure expansion machine and the medium-pressure expansion machine to the temperature close to the environment by using underground water or underground water tank water as a medium at the hot side of the three water heaters, so that the stored compression heat is saved.
Furthermore, the different degrees of flow resistance on different heights are set by casting different protruding degrees of the phase-change type heat storage plate with holes, so that the uneven air inlet at the central air inlet at the top of the heat storage type air storage tank is eliminated.
Furthermore, the bending radius of the phase-change type heat storage plate with the hole does not exceed the radius of the tank body of the heat storage type air storage tank, so that the excessive loss of the pressure of the compressed air caused by the excessively high flow resistance is prevented.
Further, along the increasing direction of the radius, the number of the vent holes per circle is increased by 5-10 to achieve uniform ventilation.
Furthermore, 5-8 phase-change heat storage sheets with holes and different bending protrusion degrees are horizontally and uniformly distributed in the height direction in the heat storage type air storage tank, and the protrusion degree of the phase-change heat storage sheets with holes is larger when the height is higher; the periphery of the heat accumulation piece is welded on the peripheral pipe wall of the heat accumulation type gas storage tank, and the flow resistance of different degrees on different heights is set by casting different projection degrees of the phase change type heat accumulation piece with holes, so that the uneven air inlet of the central air inlet at the top of the heat accumulation type gas storage tank is eliminated.
Furthermore, phase-change heat storage balls are distributed in the phase-change heat storage sheet with the holes in the heat storage type gas storage tank and are used for absorbing heat in a phase-change manner; when compressed air enters the heat accumulating type air storage tank in the system energy storage stage, the air gradually passes through the phase change type heat accumulation sheet with holes layer by layer and gradually fills the whole heat accumulating type air storage tank, and near-isothermal compression heat is stored in phase change heat accumulation balls in the phase change type heat accumulation sheet with holes; in the energy release stage, compressed air is released from the bottom of the heat accumulating type air storage tank, and because the expansion and temperature reduction of the air in the heat accumulating type air storage tank generate temperature difference, the phase change heat accumulation balls in the phase change type heat accumulation pieces with the holes are subjected to phase change heat release to heat the compressed air, so that the heat loss is reduced, and the system efficiency is improved.
Drawings
Fig. 1 is a diagram of a hot-press decoupled liquid piston compressed air energy storage system of the present invention.
Fig. 2 is a schematic view of a heat accumulating type gas storage tank according to the present invention.
Fig. 3 is a schematic sectional view of a heat accumulating type gas tank according to the present invention.
FIG. 4 is a schematic view of a phase change heat storage plate with holes according to the present invention.
FIG. 5 is a partial cross-sectional view of a phase change plate with holes according to the present invention.
Wherein: 1-a low-pressure compressor, 2-a packed bed heat accumulator, 3-a first water cooler, 4-a medium-pressure compressor, 5-a packed bed heat accumulator, 6-a second water cooler, 7-a high-pressure compressor, 8-a packed bed heat accumulator, 9-a third water cooler, 10-a heat accumulating gas storage tank, 11-a motor, 12-a generator, 13-a second air inlet valve, 14-a first air inlet valve, 15-a first air outlet valve, 16-a second air outlet valve, 17-a first liquid level sensor, 18-a second liquid level sensor, 19-a first water inlet valve, 20-a second water inlet valve, 21-a first water outlet valve, 22-a second water outlet valve, 23-a water pump unit, 24-a gas-liquid separator, 25-a water supply valve, 26-an underground water tank, 27-a first high-pressure water tank, 28-a second high-pressure water tank, 29-a first water heater, 30-a high-pressure expander, 31-a second water heater, 32-a medium-pressure expander, 33-a third water heater, 34-a low-pressure expander, 35-a phase change ball, 36-phase change ball, a gas storage tank with holes, 37-39-40-a phase change-air storage tank with holes.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
compared with adiabatic compressed air energy storage, the near-isothermal compressed air energy storage has high compression efficiency, does not need heat storage equipment, saves a large amount of equipment purchasing cost, and avoids heat transfer loss of a heat exchanger and heat dissipation in the heat storage process of the heat storage equipment; the double-tank type near-isothermal compressed air energy storage system is one type of near-isothermal air energy storage system, and alternately compresses air to a target pressure working condition by driving liquid levels in two high-pressure water tanks to alternately rise through a circulating water pump.
The packed bed regenerators comprise a first packed bed regenerator 2, a second packed bed regenerator 5, a third packed bed regenerator 8; the water cooler comprises a first water cooler 3, a second water cooler 6 and a third water cooler 9; the water heaters include a first water heater 29, a second water heater 31, and a third water heater 33.
Referring to fig. 1, the hot-press decoupled liquid piston compressed air energy storage system provided by the invention comprises a compressed air energy storage unit, a heat exchange and heat storage unit and an expansion generator set; the compressed air energy storage unit comprises a changeable compressed air system and a double-tank type near isothermal compressed air energy storage system; the multi-variable compressed air system comprises a low-pressure compressor 1, a medium-pressure compressor 4 and a high-pressure compressor 7, wherein the low-pressure compressor 1, the medium-pressure compressor 4 and the high-pressure compressor 7 are connected with a motor 11, and the motor 11 is driven by surplus electric energy; the heat exchange and heat storage unit comprises a first water cooler 3, a second water cooler 6, a third water cooler 9, a first water heater 29, a second water heater 31, a third water heater 33, a first packed bed heat accumulator 2, a second packed bed heat accumulator 5 and a third packed bed heat accumulator 8; the low-pressure compressor 1, the hot side of the first packed bed heat accumulator 2, the hot side of the first water cooler 3, the medium-pressure compressor 4, the hot side of the second packed bed heat accumulator 5, the hot side of the second water cooler 6, the high-pressure compressor 7, the hot side of the third packed bed heat accumulator 8 and the hot side of the third water cooler 9 are sequentially communicated along the flow direction of a medium; the outlet of the heat accumulating type air storage tank 10 is communicated with the cold side inlet of the first water heater 29;
the expansion generator set comprises a high-pressure expander 30, a medium-pressure expander 32 and a low-pressure expander 34, wherein the high-pressure expander 30, the medium-pressure expander 31 and the low-pressure expander 32 are connected with the generator 12, and the generator is connected with a power grid 35; the cold side of the first water heater 29, the cold side of the third packed bed regenerator 8, the high pressure expander 30, the cold side of the second water heater 31, the cold side of the second packed bed regenerator 5, the cold side of the intermediate pressure expander 32, the cold side of the third water heater 33, the first packed bed regenerator 2 and the low pressure expander 34 are communicated in the media flow direction, the low pressure expander 34 outlet is vented and the inlet of the low pressure compressor 1 is the air inlet of the system.
The double-tank type near-isothermal compressed air energy storage system comprises a heat accumulating type air storage tank 10, a first high-pressure water tank 27, a second high-pressure water tank 28, a water circulation pipeline, a gas inlet and outlet pipeline and a circulating water pump unit 23; the water outlet of the first high-pressure water gas tank 27 is communicated with the water inlet of the second high-pressure water gas tank 28 through a pipeline, and a water pump unit 23 is arranged on the pipeline; the water inlet of the first high-pressure water gas tank 27 is communicated with the water outlet of the second high-pressure water gas tank 28, and the water pump unit 23 is arranged on the pipeline; the water inlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are arranged and share the gas-liquid separator 24, and the water inlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are respectively provided with a first water inlet valve 19 and a second water inlet valve 20; the water outlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are respectively provided with a first drain valve 21 and a second drain valve 22; the first high-pressure water tank and the second high-pressure water tank are respectively provided with a first liquid level sensor 17 and a second liquid level sensor 18, the water inlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are communicated with an underground water tank 26 or other water sources through a water pump unit 23, and a water replenishing valve 25 is arranged on a pipeline from the underground water tank 26 or other water sources to the water pump unit 23; the air inlets of the first high-pressure water air tank 27 and the second high-pressure water air tank 28 are communicated with the air outlets of the heat exchange and heat storage units, and the air outlet of the third water cooler 9 in the highest stage of heat exchange and heat storage unit is used as the air outlet of the heat exchange and heat storage unit; the pipelines from the heat exchange and heat storage unit to the air inlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are respectively provided with a first air inlet valve 14 and a second air inlet valve 13, the air outlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 are communicated with the heat storage air storage tank 10, and the pipelines from the air outlets of the first high-pressure water tank 27 and the second high-pressure water tank 28 to the heat storage air storage tank 10 are respectively provided with a first exhaust valve 15 and a second exhaust valve 16.
Referring to fig. 1, in order to stabilize the working condition of air entering the expander, a throttle valve is required to be installed to obtain air flow with stable pressure, so that the pressure of the air before entering the expander for expansion is less than the storage pressure of the air, and the heat generated in the air compression process is higher than the heat required for expansion of the air, which causes the problem of unbalanced heat supply and demand in the energy storage and energy release processes.
Referring to fig. 1, the heat exchange and heat storage unit is used for storing compression heat generated in the air compression process of the polytropic compressed air system, and the compressed air energy storage unit comprises the polytropic compressed air system and a double-tank type near-isothermal compressed air energy storage system, so that pressure potential energy is obtained and stored flexibly, decoupling and combining of heat energy and pressure potential energy are achieved, heat energy and pressure potential energy are stored separately, and heat energy required for releasing the pressure potential energy is distributed efficiently.
Referring to fig. 1, hot side inlets of packed bed heat accumulators included in the heat exchange and heat storage unit are respectively communicated with outlets of a low-pressure compressor 1, a medium-pressure compressor 4 and a high-pressure compressor 7, and hot side outlets are respectively communicated with hot side inlets of water coolers included in the heat exchanger unit; cold side inlets of the three packed bed heat accumulators are respectively communicated with cold side outlets of three water heaters contained in the heat exchanger unit, and the cold side outlets are respectively communicated with inlets of a high-pressure expander 30, a medium-pressure expander 32 and a low-pressure expander 34; hot side outlets of the first water cooler 3 and the second water cooler 6 are respectively communicated with inlets of the medium-pressure compressor 4 and the high-pressure compressor 7, and a hot side outlet of the third water cooler 9 is communicated with an air inlet of the double-tank type near-isothermal compressed air energy storage system and is used as a connecting section of the multi-variable compression system and the double-tank type near-isothermal compressed air energy storage system; the three water coolers use underground water or an underground water tank 26 as a cold side medium to cool the compressed air to normal temperature so as to reduce the working energy consumption of the low-pressure compressor 1, the medium-pressure compressor 4 and the high-pressure compressor 7; outlets of the high-pressure expander 30 and the medium-pressure expander 32 are respectively communicated with cold side inlets of a second water heater 31 and a third water heater 33, outlets of the heat accumulating type air storage tanks are communicated with cold side inlets of the first water heater 29, and the three water heaters preheat air at outlets of the heat accumulating type air storage tank 10, the high-pressure expander 30 and the medium-pressure expander 32 to be near to the ambient temperature by using underground water or underground water tank water as hot-side media of the three water heaters, so that stored compression heat is saved.
Referring to fig. 2, 3, 4 and 5, the heat accumulating type gas storage tank 10 is a vertical type gas storage tank, 5 to 8 phase change type heat accumulation sheets 36 with holes are horizontally arranged in the heat accumulating type gas storage tank 10 along the height direction, the phase change type heat accumulation sheets 36 with holes are gradually bent and protruded from the edge to the middle, and the higher the height is, the larger the protrusion degree of the phase change type heat accumulation sheets 36 with holes is; the curvature radius of the plane surface of the phase-change type heat storage sheet 36 with the holes in the vertical direction does not exceed the radius of the tank body of the heat storage type air storage tank 10, so that the excessive loss of the pressure of the compressed air caused by the overhigh flow resistance is prevented; the periphery of the heat accumulation sheet is welded on the peripheral pipe wall of the heat accumulation type gas storage tank, and the flow resistance of different degrees on different heights is set by casting different projection degrees of the phase change type heat accumulation sheet with holes, so that the uneven air inlet of the central air inlet at the top of the heat accumulation type gas storage tank 10 is eliminated.
In the energy storage process, partial heat is generated in the near isothermal compression process to increase the temperature of the air, and when the air enters from the top of the heat accumulating type air storage tank 10, the porous phase-change heat accumulation sheets 36 with the heat accumulation function distributed at different heights of the heat accumulating type air storage tank 10 gradually absorb the heat of the air; in the energy releasing process, the heat accumulating type air storage tank 10 releases air, the air generates temperature difference with the phase change type heat accumulating sheet 36 with holes due to expansion and temperature reduction, the phase change material in the phase change heat accumulating ball 37 changes phase and releases heat to the air, and the air is heated and enters the packed bed heat accumulator.
Referring to fig. 4 and 5, phase-change heat storage balls 37 are distributed in the phase-change heat storage sheet 36 with holes in the heat storage type air storage tank for absorbing heat through phase change, and the balls are uniformly distributed in the phase-change heat storage sheet 36 with holes and the number of distributed layers is not more than 2; the phase-change type heat storage plate with holes is distributed with different numbers of vent holes 38 along different radius directions, the interval of the vent holes 38 is about 1/2-2/3 of the diameter of the vent holes, and the number of the vent holes 38 per circle is increased by 5-10 along the increasing direction of the distribution radius to achieve uniform ventilation.
Referring to fig. 1, 3, 4 and 5, in the energy storage process, since a portion of heat is generated in the near-isothermal compression process to raise the temperature of air, when air enters from the top of the heat accumulating type air storage tank 10, the phase-change type heat accumulation plates 36 with holes, which are distributed at different heights of the heat accumulating type air storage tank 10 and have a heat accumulating function, gradually absorb the heat of the air; in the energy releasing process, the heat accumulating type air storage tank 10 releases air, the air generates temperature difference with the phase change type heat accumulating sheet 36 with holes due to expansion and temperature reduction, the phase change material in the phase change heat accumulating ball 37 changes phase and releases heat to the air, and the air is heated and enters the water heater and the packed bed heat accumulator.
Based on the system, the invention discloses a hot-pressing decoupling liquid piston compressed air energy storage and release method, which comprises the following steps:
in the preset stage, the water in the first high-pressure water gas tank 27 and the second high-pressure water gas tank 28 is supplemented to the preset liquid level through the water supplementing pipe opening, then the water supplementing valve 25 is closed, and the water supplementing valve 25 is not opened any more to supplement water under the condition of no liquid loss.
In the energy storage stage, air firstly enters a changeable compressed air system for compression, the air from the atmosphere is compressed by a low-pressure compressor 1, an intermediate-pressure compressor 4 and a high-pressure compressor 7 in sequence, and reaches a proper intermediate pressure after heat release of a packed bed heat accumulator and a water cooler after each stage of compressor, and then is communicated with an air inlet pipe orifice of a double-tank type near isothermal compressed air energy storage system, the air inlet pipe orifice is communicated with an air inlet pipeline, and an air outlet pipe orifice of the double-tank type near isothermal compressed air energy storage system is communicated with an air outlet pipeline. Gas reaching the intermediate pressure enters from the gas inlet pipe orifice, the second gas inlet valve 13, the first gas exhaust valve 15 and the second gas exhaust valve 16 are closed while the first gas inlet valve 14 is opened, the first gas exhaust valve 21 and the second gas inlet valve 20 are opened while the gas in the gas inlet pipeline enters the first high-pressure water tank 27, the second gas exhaust valve 22 and the first gas inlet valve 19 are closed simultaneously, water in the first high-pressure water tank 27 is pressed into the second high-pressure water tank 12 through the gas-liquid separator 24 and the water pump unit 23 in sequence, the internal gas pressure is increased along with the increase of the liquid level in the second high-pressure water tank 28, when the gas pressure in the second high-pressure water tank 28 is not less than the gas pressure in the gas exhaust pipeline, the second gas exhaust valve 16 is opened, the compression is continued until the liquid level reaches the preset sensing liquid level of the second liquid level sensor 18, the second gas exhaust valve 16 is closed, the second gas exhaust valve 22 is opened, the first gas inlet valve 19 is opened, the second gas inlet valve 13 is opened, the second gas inlet valve 20, the first gas exhaust valve 21 and the first gas exhaust valve 14 are closed until the gas inlet pipeline 28 and the gas pressure in the gas tank 27 reaches the first high-pressure sensor, the first high-pressure water tank 15, and the gas pump unit 17 is not less than the gas pressure in the first high-pressure water tank 27. The valve is adjusted in a reciprocating mode, circulation pressurization is carried out, compressed air is filled into the heat accumulating type air storage tank 10 from the top of the heat accumulating type air storage tank 10 through the exhaust pipeline, the compressed air passes through the phase change type heat accumulation piece 36 with the holes layer by layer and gradually fills the whole heat accumulating type air storage tank 10, near-isothermal compression heat is stored in the phase change heat accumulation balls 37 in the phase change type heat accumulation piece 36 with the holes, and the temperature of the contact air of the phase change type heat accumulation piece 10 with the holes in the top layer is the highest, so that more heat is absorbed. In the process that the air inlet and the water outlet of the high-pressure water tank are carried out simultaneously, the volume flow is the same, so that the stability of the air pressure in the tank can be ensured.
When the system releases energy, compressed air is released from the bottom of the heat accumulating type air storage tank 10, temperature difference is generated between expansion cooling of air in the heat accumulating type air storage tank 10 and the phase change type heat accumulation sheet 36 with the holes, phase change materials in the phase change heat accumulation balls 37 in the phase change type heat accumulation sheet 36 with the holes change the heat, the air absorbs the heat and heats up, then the compressed air is preheated by the water heaters before the stages of the high-pressure expander 30, the medium-pressure expander 32 and the low-pressure expander 34 and is heated by the packed bed heat accumulator to form high-temperature high-pressure air, the high-temperature high-pressure air enters the high-pressure expander 30, the medium-pressure expander 32 and the low-pressure expander 34 step by step to expand to drive the generator 12 to generate electricity, and the generated electricity is merged into the power grid 35.
Claims (10)
1. A hot-pressing decoupling liquid piston compressed air energy storage system is characterized by comprising a changeable compressed air system, a double-tank type near-isothermal compressed air energy storage system, a heat exchange and heat storage unit and an expansion generator set; the changeable compressed air system comprises a multi-stage compressor, wherein the outlet of each stage of compressor from low to high is provided with a heat exchange and heat storage unit, the gas outlet of the last stage of heat exchange and heat storage unit is connected with the gas inlet of a double-tank type near-isothermal compressed air energy storage system, the compressor is connected with the hot side of the heat exchange and heat storage unit, the gas outlet of the double-tank type near-isothermal compressed air energy storage system is sequentially connected with a heat storage type gas storage tank (10), an expansion generator set comprises a multi-stage expander, and the working medium inlet of each stage of expander is connected with the cold side of the heat exchange and heat storage unit; the gas outlet of the heat accumulating type gas storage tank (10) is connected with the gas inlet on the cold side of the heat exchange and heat accumulation unit of the inlet of the highest stage of expansion machine, the multi-stage compressor set is driven by a motor, and the expansion generator set is connected with a generator; the inlet of the double-tank type near-isothermal compressed air energy storage system is connected with a circulating water pump (23) and an underground water tank (26).
2. The hot-pressing decoupled liquid piston compressed air energy storage system according to claim 1, wherein the heat exchange and heat storage unit comprises a packed bed heat storage, a water cooler and a water heater, a hot side inlet of the packed bed heat storage is connected with a compressor outlet, a hot side outlet of the packed bed heat storage is connected with a hot side inlet of the water cooler, and a hot side outlet of the water cooler is connected with a compressor inlet; a cold side inlet of the highest level of water heater is used as a gas inlet of a cold side of the heat exchange and heat accumulation unit, a cold side outlet of the water heater is connected with a cold side inlet of the packed bed heat accumulator, and a cold side outlet of the packed bed heat accumulator is connected with an expansion machine; the hot side of the water heater and the cold side of the water cooler are both connected with an underground water source or an underground water tank (26).
3. The hot-press decoupled liquid piston compressed air energy storage system according to claim 1, wherein the multi-stage compressor set comprises a low-pressure compressor (1), an intermediate-pressure compressor (4) and a high-pressure compressor (7) which are arranged along the air flow direction, and the expansion generator set comprises inlets of a high-pressure expander (30), an intermediate-pressure expander (32) and a low-pressure expander (34) which are arranged in sequence along the air flow direction; hot side outlets of the first water cooler (3) and the second water cooler (6) are respectively communicated with inlets of the medium-pressure compressor (4) and the high-pressure compressor (7), and a hot side outlet of the third water cooler (9) is communicated with an air inlet of the double-tank type near-isothermal compressed air energy storage system and is used as a connecting section of the polytropic compression system and the near-isothermal compression system; outlets of the high-pressure expander (30) and the medium-pressure expander (32) are respectively communicated with cold side inlets of a second water heater (31) and a third water heater (33), and an outlet of the heat accumulating type air storage tank (10) is communicated with a cold side inlet of a first water heater (29).
4. The hot-press decoupling liquid piston compressed air energy storage system according to claim 1, wherein the heat accumulating type air storage tank (10) adopts a vertical tank, 5-8 perforated phase change type heat accumulation sheets (36) are horizontally and uniformly distributed in the heat accumulating type air storage tank (10) along the height direction, the perforated phase change type heat accumulation sheets (36) are gradually bent and protruded from the edge to the middle, and the higher the height is, the larger the protrusion degree of the perforated phase change type heat accumulation sheets (36) is; the bending radius of the phase-change type heat storage sheet (36) with the holes does not exceed the radius of the tank body of the heat storage type air storage tank (10); one circle of the phase-change type heat accumulation sheet (36) with holes is welded on the peripheral pipe wall of the heat accumulation type gas storage tank.
5. The hot-press decoupled liquid piston compressed air energy storage system according to claim 4, wherein phase change heat storage balls (37) are distributed in the phase change heat storage sheet (36) with holes in the heat storage air tank, and the balls are uniformly distributed in the phase change heat storage sheet (36) with holes and the number of the distributed layers is not more than (2); the phase-change type heat storage plate with the holes is distributed with different numbers of vent holes (38) along different radiuses, the interval of the vent holes (38) is 1/2-2/3 of the diameter of the vent holes, and the number of the vent holes (38) in each circle is increased by 5-10 along the increasing direction of the radiuses.
6. The hot-press decoupling liquid piston compressed air energy storage system according to claim 1, wherein the double-tank near-isothermal compressed air energy storage system comprises a first high-pressure water tank (27) and a second high-pressure water tank (28), the first high-pressure water tank (27) and the second high-pressure water tank (28) are provided with two pipelines for communicating a water inlet and a water outlet, the communicating pipelines of the water inlets and the water outlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) are provided with gas-liquid separators (24), and the water inlets and the water outlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) are provided with valves; the first high-pressure water gas tank and the second high-pressure water gas tank are both provided with liquid level sensors, and the water inlets of the first high-pressure water gas tank (27) and the second high-pressure water gas tank (28) are communicated with an underground water tank (26) through a water pump unit (23); the air inlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) are communicated with the air outlet of the heat exchange and heat storage unit, the pipelines from the heat exchange and heat storage unit to the air inlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) are respectively provided with a valve, the air outlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) are communicated with the heat storage air storage tank (10), and the pipelines from the air outlets of the first high-pressure water tank (27) and the second high-pressure water tank (28) to the heat storage air storage tank (10) are respectively provided with a valve.
7. The hot-press decoupled liquid piston compressed air energy storage system according to claim 1, characterized in that the electrical energy output of the generator is connected to the electrical network (35) and/or to an electric motor for driving the multistage compressor and to a water pump.
8. The operation method of the hot-press decoupling liquid piston compressed air energy storage system based on any one of claims 1 to 7 is characterized in that in a preset stage, water is supplemented to a set water level in the double-tank type near-isothermal compressed air energy storage unit;
when the system stores energy, air is compressed by the multistage compressor, the compressed air releases heat in the heat exchange and heat storage unit at the outlet of each stage of compressor, enters the double-tank type near-isothermal compressed air energy storage system through the last stage heat exchange and heat storage unit and is compressed to a target pressure, and the air reaching the target pressure enters the heat storage type air storage tank (10) for storing energy; the double-tank type near-isothermal compressed air energy storage system pumps water from an underground water tank (26) for pressurization;
when the system releases energy, compressed air is released from the bottom of the heat storage type air storage tank (10), and the compressed air enters the expansion machine to do work to drive the generator to generate power after absorbing heat and raising temperature in the heat exchange and heat storage unit at the working medium inlet of each stage of expansion machine set;
the variable compressed air system is used as low-pressure-stage compressed air at the energy storage side of the whole system, the double-tank type near-isothermal compressed air system is used as high-pressure-stage compressed air at the energy storage side of the whole system, an outlet of the variable compressed air system is connected with an inlet of the double-tank type near-isothermal compressed air system, and the compression ratio of a water tank in the double-tank type near-isothermal compressed air system is matched and adjusted to reach the target pressure by adjusting the compression ratio of each stage of compressor in the variable compressed system, so that the compression heat generated by the compressed air in the energy storage process can be fully utilized in the energy release process; and the heat exchange and heat storage unit is used for storing the compression heat generated in the air compression process of the multivariable compressed air system.
9. The operation method according to claim 8, wherein 5 to 8 phase-change heat storage plates (36) with holes are horizontally and uniformly distributed in the heat storage type air storage tank (10) along the height direction, and phase-change heat storage balls (37) are distributed in the phase-change heat storage plates (36) with holes in the heat storage type air storage tank; air is compressed to a target pressure through a double-tank type near-isothermal compressed air energy storage system and enters from the top of a heat accumulating type air storage tank (10), the air passes through a porous phase-change type heat accumulation sheet (36) layer by layer and gradually fills the whole heat accumulating type air storage tank (10), near-isothermal compressed heat is stored in a phase-change heat accumulation ball (37) in the porous phase-change type heat accumulation sheet (36), and the porous phase-change type heat accumulation sheet (36) at the top layer absorbs most heat due to the fact that the temperature of the air is highest;
when the system releases energy, compressed air is released from the bottom of the heat accumulating type air storage tank (10), the expansion and temperature reduction of the air in the heat accumulating type air storage tank (10) and the phase change type heat accumulation sheet (36) with holes generate temperature difference, phase change materials in the phase change heat accumulation balls (37) in the phase change type heat accumulation sheets with holes change heat and release heat, the air absorbs heat and heats up, and then the compressed air enters the expansion unit step by step after being subjected to pre-heat exchange by the heat exchange and heat accumulation unit.
10. Method of operation according to claim 8, characterized in that the electricity generated by the generator is used for the electric motor and the pump unit (23) incorporated in the electric network, the compressor.
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| CN117691642A (en) * | 2024-02-02 | 2024-03-12 | 百穰新能源科技(深圳)有限公司 | Energy storage system energy release control method, system, control equipment and storage medium |
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| CN117691642A (en) * | 2024-02-02 | 2024-03-12 | 百穰新能源科技(深圳)有限公司 | Energy storage system energy release control method, system, control equipment and storage medium |
| CN117691642B (en) * | 2024-02-02 | 2024-05-10 | 百穰新能源科技(深圳)有限公司 | Energy storage system energy release control method, system, control equipment and storage medium |
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