CN114991896A - Closed type circulating energy storage system and method - Google Patents

Abstract

The invention discloses a closed cycle energy storage system and a method, wherein a cooling and cold accumulation liquefaction system is connected with a compressor, and the compressor is communicated with a cooler; the cooler is connected with an inlet of the low-temperature expansion liquefaction system, an outlet of the low-temperature expansion liquefaction system is connected with the liquid centrifugal pump, the liquid centrifugal pump is connected with the circulating water heater, the circulating water heater is connected with the heater, the heater is connected with the expander, the expander is connected with the condenser, and the condenser is connected with the cooling and cold accumulation liquefaction system; the heat storage tank is connected with the cooler, the heat storage tank is connected with the heater, the heater is connected with the cold storage tank, and the cold storage tank is connected with the cooler; the circulating pump is connected with the cold and hot heat storage water tank, the circulating pump is connected with the condenser, the condenser is connected with the circulating water heater, and the circulating water heater is connected with the cold and hot heat storage water tank. The invention can meet the requirements of energy storage and deep peak regulation on the power supply side and has the characteristics of higher safety and economy.

Description

A closed cycle energy storage system and method

technical field

The invention belongs to the field of physical energy storage, and relates to a closed cycle energy storage system and method.

Background technique

With the increasing proportion of new energy in the power system, such as "the output of new energy fluctuates greatly, the power balance and operation control are extremely difficult, the consumption of new energy is difficult when the power generation is large, the space for conventional power is crowded, and the consumption of new energy is difficult. Problems such as “prominent conflict with safety” will bring huge challenges to the power system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and to provide a closed-cycle energy storage system and method, which can meet the requirements of power-side energy storage and deep peak regulation, and is safe and economical higher characteristics.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A closed-cycle energy storage system, including a compressor, a cooler, a low-temperature expansion liquefaction system, a liquid centrifugal pump, a circulating water heater, a heater, an expander, a condenser, a cold and hot water storage tank, a circulating pump, a storage Heat tank, cold storage tank and cooling storage liquefaction system, the carbon dioxide gas outlet of the cooling storage liquefaction system is connected with the compressor inlet, and the compressor outlet is connected with the heat absorption side inlet of the cooler; the low temperature expansion liquefaction system can convert carbon dioxide gas into liquid carbon dioxide , The outlet of the heat absorption side of the cooler is connected to the carbon dioxide gas inlet of the low temperature expansion liquefaction system, the carbon dioxide liquid outlet of the low temperature expansion liquefaction system is connected to the inlet of the liquid centrifugal pump, the outlet of the liquid centrifugal pump is connected to the cold inlet of the circulating water heater, and the circulating water is heated. The cold outlet of the heater is connected with the cold inlet of the heater, the cold outlet of the heater is connected with the inlet of the expander, the outlet of the expander is connected with the hot inlet of the condenser, and the hot outlet of the condenser is connected with the carbon dioxide inlet of the cooling and storage liquefaction system. ;

The inlet of the thermal storage tank is connected with the cold outlet of the cooler, the outlet of the thermal storage tank is connected with the hot inlet of the heater, the hot outlet of the heater is connected with the inlet of the cold storage tank, and the outlet of the thermal storage tank is connected with the cold inlet of the cooler;

The inlet of the circulating pump is connected with the outlet of the cold and hot water storage tank, the outlet of the circulating pump is connected with the cold inlet of the condenser, the cold outlet of the condenser is connected with the hot inlet of the circulating water heater, and the hot outlet of the circulating water heater is connected with the cold inlet. The inlet connection of the thermal storage hot water tank.

Preferably, the compressor includes a first-stage compressor and a second-stage compressor, the cooler includes a first-stage interstage cooler and a second-stage interstage cooler, and the outlet of the first-stage compressor is connected to the heat absorption side of the first-stage interstage cooler Inlet, the outlet of the discharge and suction side of the primary interstage cooler is connected to the inlet of the secondary compressor, the outlet of the secondary compressor is connected to the inlet of the heat absorption side of the secondary interstage cooler, and the outlet of the heat absorption side of the secondary interstage cooler is connected to the low temperature The inlet of the expansion liquefaction system;

The inlet of the heat storage tank is connected with the cold outlet of the primary interstage cooler and the second interstage cooler, the outlet of the heat storage tank is connected with the hot inlet of the heater, the hot outlet of the heater is connected with the inlet of the cold storage tank, and the cold storage The tank outlet communicates with both the primary interstage cooler and the cold inlet of the secondary interstage cooler.

Preferably, the expander includes a primary expander and a secondary expander, the heater includes a primary heater and a secondary heater, the cold outlet of the circulating water heater is connected to the cold inlet of the primary heater, and the primary heater The cold outlet of the primary expander is connected to the inlet of the primary expander, the outlet of the primary expander is connected to the cold inlet of the secondary heater, the cold outlet of the secondary heater is connected to the inlet of the secondary expander, and the outlet of the secondary expander is connected. It is connected with the heat inlet of the condenser; the outlet of the heat storage tank is communicated with the heat inlet of the primary heater and the secondary heater, and the heat outlet of the primary heater and the secondary heater is communicated with the inlet of the cold storage tank.

Preferably, the low-temperature expansion liquefaction system includes a low-temperature expander, a first throttle valve and a first liquid storage tank; the outlet on the heat absorption side of the cooler is connected to the inlet of the low-temperature expander, and the outlet of the low-temperature expander is connected to the first liquid storage tank, A first throttle valve is arranged on the pipeline connecting the cryogenic expander and the first liquid storage tank, and the outlet of the first liquid storage tank is connected with the inlet of the liquid centrifugal pump.

Preferably, the cooling and storage liquefaction system includes a deep regenerator and a second liquid storage tank, the heat outlet of the condenser is connected to the inlet of the heat absorption side of the deep regenerator, and the outlet of the heat absorption side of the deep regenerator is connected to the inlet of the second liquid storage tank, and the first The outlet of the two liquid storage tanks is connected with the inlet of the heat release side of the deep regenerator and the connecting pipeline is provided with a second throttle valve, and the outlet of the heat release side of the deep regenerator is connected with the inlet of the expander.

The present invention also provides a closed-cycle energy storage method, which adopts the closed-cycle energy storage system of the present invention as described above, and includes the following processes:

When energy storage is needed on the power supply side, the cooling and storage liquefaction system provides gaseous CO ₂ to the compressor, and the compressor compresses and warms the gaseous CO ₂ . The gaseous CO ₂ after heat exchange by the cooler is converted into liquid CO ₂ by the low-temperature expansion liquefaction system and stored; when the compression heat after compression and temperature rise passes the heat exchange of the cooler, the cold working medium at the outlet of the cold storage tank enters the cooler to release heat After the side absorbs heat, it enters the heat storage tank for heat storage;

When the power supply side needs to generate electricity, the compressor will stop working, the liquid centrifugal pump will transport the liquid _CO2 stored in the low temperature expansion liquefaction system to the circulating water heater, and the liquid _CO2 entering the circulating water heater will become Gaseous CO ₂ , and then the gaseous CO ₂ is heated and heated by the heater, and sent to the expander to generate power. The gaseous CO ₂ at the outlet of the expander enters the cooling and storage liquefaction system through the heat-absorbing side of the condenser for cooling and liquefaction storage; The hot tank transports the hot working fluid to the exothermic side of the cooler to heat the gaseous CO ₂ , and the hot working medium after the heat release in the cooler enters the cold storage tank through the outlet of the exothermic side of the cooler; the circulating pump stores the cold and hot heat The water in the water tank is pumped into the exothermic side of the condenser to absorb heat. After the water is heated, it enters the heat-absorbing side of the circulating water heater to heat the liquid CO ₂ on the exothermic side of the circulating water heater into gaseous CO ₂ . After that, the water on the heat-absorbing side of the circulating water heater enters the cold and hot water storage tank.

Preferably, the pressure of the gaseous CO ₂ provided by the cooling and cold storage liquefaction system to the compressor is 0.6-0.8 MPa and the temperature is 10-20 ℃, the pressure of the gaseous CO ₂ at the outlet of the compressor is 14-15 MPa, and the temperature is 150-160 ℃, The pressure of gaseous CO ₂ at the outlet of the heat-absorbing side of the cooler is 14-15MPa, and the temperature is 50-60°C _; The pressure of liquid _CO2 at the pump outlet is 14-15MPa and the temperature is -40～-50℃, the pressure of gaseous _CO2 at the outlet of the exothermic side of the circulating water heater is 14～15MPa, the temperature is 10～15℃, the cooler emits heat The pressure of gaseous _CO2 at the side outlet is 14-15MPa and the temperature is 140-155℃, the pressure of gaseous _CO2 at the outlet of the expander is 1-1.2MPa and the temperature is 65-75℃, and the gaseous _CO2 at the outlet of the condenser exothermic side is 14-15MPa. The pressure is 1-1.2 MPa MPa, the temperature is 20-25 ℃, the water temperature at the outlet of the condenser exothermic side is 20-65 ℃, and the water temperature at the outlet of the heat-absorbing side of the circulating water heater is 15-20 ℃.

Preferably: the compressor comprises a primary compressor and a secondary compressor, the cooler comprises a primary interstage cooler and a secondary interstage cooler, and the outlet of the primary compressor is connected to the heat absorption side of the primary interstage cooler The inlet, the outlet of the heat-absorbing side of the first-stage interstage cooler is connected to the inlet of the second-stage compressor, the outlet of the second-stage compressor is connected to the heat-absorbing side inlet of the second-stage inter-stage cooler, and the outlet of the heat-absorbing side of the second-stage interstage cooler is connected to the low temperature The inlet of the expansion liquefaction system; the inlet of the heat storage tank is connected with the cold outlet of the primary interstage cooler and the second interstage cooler, the outlet of the heat storage tank is connected with the hot inlet of the heater, and the hot outlet of the heater is connected with The inlet of the cold storage tank is connected, and the outlet of the cold storage tank is connected with the cold inlet of the primary interstage cooler and the secondary interstage cooler;

The gaseous _{CO 2} pressure at the outlet of the primary compressor is 2.88-3MPa, and the temperature is 140-155°C. The gaseous CO ₂ pressure at the outlet of the stage compressor is 14-15MPa and the temperature is 150-160°C, and the gaseous CO ₂ pressure at the outlet of the heat-absorbing side of the secondary interstage cooler is 14-15MPa and the temperature is 50-60°C;

Preferably: the expander includes a primary expander and a secondary expander, the heater includes a primary heater and a secondary heater, the cold outlet of the circulating water heater is connected to the cold inlet of the primary heater, and the primary heater The cold outlet of the primary expander is connected to the inlet of the primary expander, the outlet of the primary expander is connected to the cold inlet of the secondary heater, the cold outlet of the secondary heater is connected to the inlet of the secondary expander, and the outlet of the secondary expander is connected. It is connected with the heat inlet of the condenser; the outlet of the heat storage tank is communicated with the heat inlet of the primary heater and the secondary heater, and the heat outlet of the primary heater and the secondary heater is communicated with the inlet of the cold storage tank;

The pressure of gaseous CO ₂ at the outlet of the exothermic side of the primary heater is 14-15MPa and the temperature is 140-155°C; the pressure of gaseous CO ₂ at the outlet of the exothermic side of the secondary heater is 3.5-4MPa and the temperature is 150-165°C. The gaseous CO ₂ pressure at the outlet of the secondary expander is 1-1.2MPa, and the temperature is 65-75°C.

Preferably: the low-temperature expansion liquefaction system includes a low-temperature expander, a first throttle valve and a first liquid storage tank; the outlet on the heat-absorbing side of the cooler is connected to the inlet of the low-temperature expander, and the outlet of the low-temperature expander is connected to the first liquid storage tank, A first throttle valve is set on the pipeline connecting the low temperature expander and the first liquid storage tank, and the outlet of the first liquid storage tank is connected with the inlet of the liquid centrifugal pump _; is -40～-60℃, the pressure of liquid _CO2 at the outlet of the first throttle valve is 0.55～0.6MPa, and the temperature is -53～-55℃;

The cooling and cold storage liquefaction system includes a deep cold accumulator and a second liquid storage tank. The heat outlet of the condenser is connected to the heat absorption side inlet of the deep cold accumulator, and the heat absorption side outlet of the deep cold accumulator is connected to the inlet of the second liquid storage tank. The outlet of the tank is connected with the inlet of the heat-releasing side of the deep regenerator and the connecting pipeline is provided with a second throttle valve, the outlet of the heat-releasing side of the deep regenerator is connected with the inlet of the expander; the gaseous _CO2 pressure of the inlet of the heat-absorbing side of the deep regenerator is 1 ～1.2MPa, the temperature is 20～25℃, the outlet of the heat-absorbing side of the deep regenerator is liquid CO ₂ , the pressure of the liquid CO ₂ is 0.9～1MPa, the temperature is -42～-40℃, the liquid CO 2 stored in the second liquid storage tank is The pressure of _CO2 is 0.9～1MPa, the temperature is -42～-40℃, the pressure of liquid _CO2 at the outlet of the second throttle valve is 0.6～0.8MPa, the temperature is -38～-35℃, the outlet of the heat release side of the deep regenerator The pressure of gaseous CO ₂ is 0.6-0.8MPa and the temperature is 10-20℃.

The present invention has the following beneficial effects:

During specific operation, the closed-cycle energy storage system and method of the present invention utilizes excess power in low valleys to compress _CO2 energy storage, realizes energy storage and peak regulation on the power supply side, keeps the power supply side in stable operation all the time, and solves the problem of rapid peak regulation in depth. The potential harm caused by the variable load to the unit and auxiliary equipment. Specifically, when the power supply side needs deep peak regulation, the CO ₂ is compressed and heated by the compressor and cooler, and the compressed and heated CO ₂ passes through the low-temperature expansion and liquefaction system. The gaseous state is converted into a liquid state for storage. The liquid _CO2 is small in size and easy to store. It completely solves the constraints caused by compressed air storage, and at the same time consumes electric energy to achieve deep peak regulation. In addition, when the power supply side needs to generate electricity and supply power, the thermal working fluid and liquid stored in the thermal storage tank are used to generate electricity through the heating and expansion power generation system, which can quickly provide stable power to the outside world. It has the advantages of simple system, rapid response and strong energy storage capacity It has the characteristics of high potential for deep peak regulation, high safety and economy, and the electricity-to-electricity conversion efficiency can reach more than 70%.

Description of drawings

FIG. 1 is a schematic structural diagram of a closed cycle energy storage system of the present invention.

Among them, 1 is a primary compressor, 2 is a primary interstage cooler, 3 is a secondary compressor, 4 is a secondary interstage cooler, 5 is a low temperature expander, 6 is a first throttle valve, and 7 is a The first liquid storage tank, 8 is a heat storage tank, 9 is a cold storage tank, 10 is a liquid centrifugal pump, 11 is a circulating water heater, 12 is a primary heater, 13 is a primary expander, and 14 is a secondary heater , 15 is a secondary expander, 16 is a condenser, 17 is a cold and hot water storage tank, 18 is a circulating pump, 19 is a cryogenic cold storage tank, 20 is a second throttle valve, and 21 is a second liquid storage tank.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in FIG. 1, the closed-cycle energy storage system of the present invention includes a compressor, a cooler, a low-temperature expansion liquefaction system, a liquid centrifugal pump 10, a circulating water heater 11, a heater, an expander, a condenser 16, a cooling and heating Hot water storage tank 17, circulating pump 18, thermal storage tank 8, cold storage tank 9 and cooling and cooling storage liquefaction system, the cooling and cooling storage liquefaction system includes a deep cold storage tank 19 and a second liquid storage tank 21, the heat outlet of the condenser 16 and the deep cooling storage liquefaction system The inlet of the heat-absorbing side of the deep regenerator 19 is connected to the inlet of the heat-absorbing side of the deep regenerator 19, the outlet of the heat-absorbing side of the deep regenerator 19 is connected to the inlet of the second liquid storage tank 21, the outlet of the second liquid storage tank 21 is connected to the inlet of the heat-releasing side of the deep regenerator 19, and the connecting pipeline is provided with The second throttle valve 20; the compressor includes a primary compressor 1 and a secondary compressor 3, the cooler includes a primary interstage cooler 2 and a secondary interstage cooler 4, and the outlet of the heat release side of the deep regenerator 19 is connected to The inlet of the first stage compressor 1 is connected, the outlet of the first stage compressor 1 is connected to the inlet of the heat absorption side of the first stage inter-stage cooler 2, and the outlet of the heat absorption side of the first stage interstage cooler 2 is connected to the inlet of the second stage compressor 3. The outlet of the machine 3 is connected to the inlet of the heat absorption side of the secondary interstage cooler 4, and the low temperature expansion liquefaction system includes a low temperature expander 5, a first throttle valve 6 and a first liquid storage tank 7; the secondary interstage cooler 4 absorbs heat The side outlet is connected to the inlet of the low-temperature expander 5, the outlet of the low-temperature expander 5 is connected to the first liquid storage tank 7, and a first throttle valve 6 is arranged on the pipeline connecting the low-temperature expander 5 and the first liquid storage tank 7, and the first liquid The outlet of the storage tank 7 is connected with the inlet of the liquid centrifugal pump 10; the inlet of the heat storage tank 8 is connected with the cold outlet of the primary interstage cooler 2 and the secondary interstage cooler 4, and the outlet of the heat storage tank 8 is connected to the heater The hot inlet of the heater is connected, the hot outlet of the heater is connected with the inlet of the cold storage tank 9, and the outlet of the cold storage tank 9 is connected with the cold inlet of the primary interstage cooler 2 and the secondary interstage cooler 4; the first liquid storage tank 7 The carbon dioxide liquid outlet is connected to the inlet of the liquid centrifugal pump 10, and the outlet of the liquid centrifugal pump 10 is connected to the cold inlet of the circulating water heater 11; the expander includes a primary expander 13 and a secondary expander 15, and the heater includes a primary heater 12 and the secondary heater 14, the cold outlet of the circulating water heater 11 is connected to the cold inlet of the primary heater 12, the cold outlet of the primary heater 12 is connected to the inlet of the primary expander 13, and the primary expander 13 The outlet of the secondary heater 14 is connected to the cold inlet of the secondary heater 14, the cold outlet of the secondary heater 14 is connected to the inlet of the secondary expander 15, and the outlet of the secondary expander 15 is connected to the hot inlet of the condenser 16; The outlet of 8 is communicated with the hot inlet of the primary heater 12 and the secondary heater 14, the hot outlet of the primary heater 12 and the secondary heater 14 is communicated with the inlet of the cold storage tank 9; the inlet of the circulating pump 18 is connected with the cold and hot The outlet of the hot water storage tank 17 is connected, the outlet of the circulating pump 18 is connected with the cold inlet of the condenser 16, the cold outlet of the condenser 16 is connected with the hot inlet of the circulating water heater 11, and the hot outlet of the circulating water heater 11 is connected with the cold and hot The inlet of the hot water storage tank 17 is connected.

The working method of the above-mentioned closed-cycle energy storage system of the present invention includes the following processes:

When the power supply side needs to store energy, the liquid CO ₂ in the _second liquid storage tank 21 is depressurized by the second throttle valve and then enters the deep regenerator 19 . The primary compressor 1 provides gaseous CO ₂ , the primary compressor 1 and the secondary compressor 3 compress and heat up the gaseous CO ₂ step by step, and the heat is exchanged through the primary inter-stage cooler 2 and the secondary inter-stage cooler 4 . The heat is stored in the heat storage tank 8, the gaseous CO ₂ after heat exchange by the cooler is converted into liquid CO ₂ by the low temperature expander 5, and the liquid CO ₂ is depressurized by the first throttle valve and stored in the first liquid storage tank. In tank 7; when the heat of compression after compression and heating passes through the primary interstage cooler 2 and the secondary interstage cooler 4 for heat exchange, the cold working fluid at the outlet of the cold storage tank 9 enters the primary interstage cooler 2 and the secondary interstage cooler 4. After the heat release side of the intercooler 4 absorbs heat, it enters the heat storage tank 8 for heat storage;

When the power supply side needs to generate electricity, the primary compressor 1 and the secondary compressor 3 will stop working, and the liquid centrifugal pump 10 will transport the liquid _CO2 stored in the first liquid storage tank 7 to the circulating water heater 11 and enter the circulating water. The liquid CO ₂ in the heater 11 changes into gaseous CO ₂ after heat exchange and heating up, and then the gaseous CO ₂ is heated and raised by the primary heater 12 and sent to the primary expander 13 for power generation. The gaseous CO ₂ is then heated by the secondary heater 14 and sent to the secondary expander 15 to generate power. The gaseous CO ₂ at the outlet of the secondary expander 15 passes through the heat-absorbing side of the condenser 16 and then enters the heat-absorbing side of the deep regenerator 19 For cooling and storage, the gaseous CO ₂ entering the deep regenerator 19 releases heat and stores it in the second liquid storage tank 21 in liquid form; the heat release from the heat storage tank 8 to the primary heater 12 and the secondary heater 14 The hot working fluid is transported on the side to heat the gaseous CO ₂ entering the primary expander 13 and the secondary expander 15, and the hot working fluid after the heat release in the primary heater 12 and the secondary heater 14 is heated by the primary The outlet of the heat release side of the condenser 12 and the secondary heater 14 enters the cold storage tank 9; the circulating pump 18 pumps the water in the cold and hot water storage tank 17 into the heat release side of the condenser 16 to absorb heat, and the water is heated and enters the circulating water The heat-absorbing side of the heater 11 is used to heat the liquid CO ₂ on the heat-absorbing side of the circulating water heater 11 into gaseous CO ₂ .

In the above scheme of the present invention, the pressure of gaseous CO ₂ at the outlet of the heat release side of the deep regenerator 19 is 0.6-0.8 MPa, the temperature is 10-20 ° C, the pressure of gaseous CO ₂ at the outlet of the primary compressor 1 is 2.88-3 MPa, The temperature is 140～155℃, the gaseous _CO2 pressure at the outlet of the heat-absorbing side of the primary interstage cooler 2 is 2.88～3MPa, the temperature is 15～25℃, and the gaseous _CO2 pressure at the outlet of the secondary compressor 3 is 14～15MPa , the temperature is 150 ~ 160 ℃, the gaseous CO ₂ pressure at the outlet of the heat absorption side of the secondary interstage cooler 4 is 14 ~ 15MPa, and the temperature is 50 ~ 60 ℃; the liquid CO ₂ pressure at the outlet of the low temperature expander 5 is 1.2 ~ 1.5 MPa, the temperature is -40～-60℃, the pressure of the liquid _CO2 at the outlet of the first throttle valve 6 is 0.55～0.6MPa, and the temperature is -53～-55℃; the pressure of the liquid _CO2 stored in the first liquid storage tank 7 is 0.55～0.6MPa, the temperature is -53～-55℃, the pressure of liquid _CO2 at the outlet of the liquid centrifugal pump 10 is 14-15MPa, the temperature is -40～-50℃, the gaseous state at the outlet of the exothermic side of the circulating water heater 11 The pressure of CO ₂ is 14～15MPa, the temperature is 10～15℃, the pressure of gaseous CO ₂ is 14～15MPa, the temperature is 140～155℃, the outlet of the heat release side of the secondary heater 14 is 14～15MPa, and the temperature is 10～15℃. The pressure of gaseous CO ₂ is 3.5-4MPa, the temperature is 150-165 ℃, the pressure of gaseous CO ₂ at the outlet of the secondary expander 15 is 1-1.2 MPa, the temperature is 65-75 ℃, the gaseous state of the outlet of the condenser 16 exothermic side is 1-1.2MPa The pressure of CO ₂ is 1～1.2MPa, the temperature is 20～25℃, the water temperature at the outlet of the heat release side of the condenser 16 is 20～65℃, the temperature of the water at the outlet of the heat absorption side of the circulating water heater 11 is 15～20℃, and the deep cold storage The pressure of gaseous CO ₂ at the inlet of the exothermic side of the regenerator 19 is 1～1.2MPa and the temperature is 20～25℃, and the pressure of liquid CO ₂ at the outlet of the exothermic side of the deep regenerator 19 is 0.9～1MPa and the temperature is -42～-40℃, , the pressure of CO ₂ stored in the second liquid storage tank 21 is 0.9-1MPa and the temperature is -42--40°C, and the pressure of the liquid CO ₂ at the outlet of the second throttle valve 20 is 0.6-0.8MPa and the temperature is -38- -35°C, the gaseous CO ₂ pressure at the outlet of the heat-absorbing side of the deep regenerator 19 is 0.6-0.8MPa, and the temperature is 10-20°C. The temperature of the water in the hot and cold water storage tank 17 is 15 to 20°C.

The invention uses the special physical parameters of CO ₂ to propose a closed-cycle energy storage system, which has the following characteristics: low pressure in the gas storage chamber, high energy storage density of compressed CO ₂ in the gas storage chamber; Air energy storage is about 30% of the conventional compressed air energy storage power station, which can be arranged flexibly and is not restricted by terrain; Both are far superior to conventional compressed air energy storage.

Claims (10)

1. A closed cycle energy storage system, characterized in that it comprises a compressor, a cooler, a low temperature expansion liquefaction system, a liquid centrifugal pump (10), a circulating water heater (11), a heater, an expander, a condenser (16), cold and heat storage hot water tank (17), circulating pump (18), heat storage tank (8), cold storage tank (9) and cooling and cooling storage liquefaction system, carbon dioxide gas outlet and compressor inlet of cooling cooling storage liquefaction system The outlet of the compressor is connected to the inlet of the heat absorption side of the cooler; the low temperature expansion and liquefaction system can convert carbon dioxide gas into liquid carbon dioxide, and the outlet of the heat absorption side of the cooler is connected to the carbon dioxide gas inlet of the low temperature expansion and liquefaction system. The carbon dioxide liquid outlet is connected to the inlet of the liquid centrifugal pump (10), the outlet of the liquid centrifugal pump (10) is connected to the cold inlet of the circulating water heater (11), and the cold outlet of the circulating water heater (11) is connected to the cold inlet of the heater , the cold outlet of the heater is connected with the inlet of the expander, the outlet of the expander is connected with the hot inlet of the condenser (16), and the hot outlet of the condenser (16) is connected with the carbon dioxide inlet of the cooling storage liquefaction system; The inlet of the heat storage tank (8) is connected with the cold outlet of the cooler, the outlet of the heat storage tank (8) is connected with the hot inlet of the heater, the hot outlet of the heater is connected with the inlet of the cool storage tank (9), and the cool storage tank (9) ) is connected to the cold inlet of the cooler; The inlet of the circulating pump (18) is connected with the outlet of the cold and hot water storage tank (17), the outlet of the circulating pump (18) is connected with the cold inlet of the condenser (16), and the cold outlet of the condenser (16) is connected with the circulating water The heat inlet of the heater (11) is connected, and the heat outlet of the circulating water heater (11) is connected with the inlet of the cold and hot water storage tank (17). 2. A closed-cycle energy storage system according to claim 1, wherein the compressor comprises a primary compressor (1) and a secondary compressor (3), and the cooler comprises a primary interstage The cooler (2) and the secondary interstage cooler (4), the outlet of the primary compressor (1) is connected to the heat absorption side inlet of the primary interstage cooler (2), and the primary interstage cooler (2) absorbs heat The side outlet is connected to the inlet of the secondary compressor (3), the outlet of the secondary compressor (3) is connected to the heat absorption side inlet of the secondary interstage cooler (4), and the heat absorption side outlet of the secondary interstage cooler (4) Connect to the inlet of the low temperature expansion liquefaction system; The inlet of the heat storage tank (8) is connected with the cold outlet of the primary interstage cooler (2) and the secondary interstage cooler (4), and the outlet of the heat storage tank (8) is connected with the hot inlet of the heater, The hot outlet of the heater is connected with the inlet of the cold storage tank (9), and the outlet of the cold storage tank (9) is communicated with the cold inlets of the primary interstage cooler (2) and the secondary interstage cooler (4). 3. A closed-cycle energy storage system according to claim 2, wherein the expander comprises a primary expander (13) and a secondary expander (15), and the heater comprises a primary heater (12) ) and the secondary heater (14), the cold outlet of the circulating water heater (11) is connected to the cold inlet of the primary heater (12), and the cold outlet of the primary heater (12) is connected to the primary expander (13). ), the outlet of the primary expander (13) is connected to the cold inlet of the secondary heater (14), and the cold outlet of the secondary heater (14) is connected to the inlet of the secondary expander (15). The outlet of the stage expander (15) is connected with the hot inlet of the condenser (16); the outlet of the heat storage tank (8) is communicated with the hot inlets of the primary heater (12) and the secondary heater (14), a The hot outlet of the primary heater (12) and the secondary heater (14) communicate with the inlet of the cold storage tank (9). 4. A closed cycle energy storage system according to claim 1, characterized in that the low temperature expansion liquefaction system comprises a low temperature expander (5), a first throttle valve (6) and a first liquid storage tank (7) ); the outlet of the heat-absorbing side of the cooler is connected to the inlet of the low temperature expander (5), the outlet of the low temperature expander (5) is connected to the first liquid storage tank (7), and the low temperature expander (5) is connected to the first liquid storage tank ( 7) A first throttle valve (6) is arranged on the connected pipeline, and the outlet of the first liquid storage tank (7) is connected with the inlet of the liquid centrifugal pump (10). 5. A closed-cycle energy storage system according to claim 1, characterized in that the cooling and cold storage liquefaction system comprises a deep cold accumulator (19) and a second liquid storage tank (21), and the heat of the condenser (16) The outlet is connected to the heat-absorbing side inlet of the deep regenerator (19), the heat-absorbing side outlet of the deep regenerator (19) is connected to the inlet of the second liquid storage tank (21), and the outlet of the second liquid storage tank (21) is connected to the deep regenerator (19) The heat release side inlet is connected and the connecting pipeline is provided with a second throttle valve (20), and the heat release side outlet of the deep regenerator (19) is connected to the expander inlet. 6. A closed-cycle energy storage method, characterized in that, the method adopts the closed-cycle energy storage system according to any one of claims 1-5 to carry out, comprising the following process: When energy storage is required on the power supply side, the cooling and storage liquefaction system provides gaseous CO ₂ to the compressor, the compressor compresses and heats up the gaseous CO ₂ , and the heat of compression after compression and temperature rises is exchanged by the cooler and stored in the heat storage tank (8 ), the gaseous CO ₂ after heat exchange by the cooler is converted into liquid CO ₂ through the low-temperature expansion liquefaction system and stored; when the compression heat after the compression and temperature rise passes through the heat exchange of the cooler, the cold working medium at the outlet of the cold storage tank (9) After entering the exothermic side of the cooler to absorb heat, it enters the heat storage tank (8) for heat storage; When the power supply side needs to generate electricity, the compressor stops working, and the liquid centrifugal pump (10) transports the liquid _CO2 stored in the low-temperature expansion liquefaction system to the circulating water heater (11), and enters the circulating water heater (11). The liquid CO ₂ changes into gaseous CO ₂ after heat exchange and heating, and then the gaseous CO ₂ is heated and raised by the heater, and sent to the expander to generate power. The gaseous CO ₂ at the outlet of the expander passes through the heat-absorbing side of the condenser (16). Enter the cooling and cold storage liquefaction system for cooling and liquefaction storage; the heat storage tank (8) transports the hot working medium to the heat releasing side of the cooler to heat the gaseous CO ₂ , and the hot working medium after the heat release in the cooler passes through the cooler The outlet of the heat release side enters the cold storage tank (9); the circulation pump (18) pumps the water in the cold and hot water storage tank (17) into the heat release side of the condenser (16) to absorb heat, and the water enters the circulating water after being heated The heat-absorbing side of the heater (11) is used to heat the liquid CO ₂ on the heat-releasing side of the circulating water heater (11) into gaseous CO ₂ , and then the water on the heat-absorbing side of the circulating water heater (11) enters the cold and heat Hot water storage tank (17). 7 . A closed-cycle energy storage method according to claim 6 , wherein the pressure of the gaseous _CO provided by the cooling and cold storage liquefaction system to the compressor is 0.6-0.8 MPa, the temperature is 10-20° C., and the compression The pressure of gaseous CO ₂ at the outlet of the machine is 14-15MPa and the temperature is 150-160℃. The pressure of gaseous CO ₂ at the outlet of the heat absorption side of the cooler is 14-15MPa and the temperature is 50-60℃. The liquid CO stored in the low temperature expansion liquefaction system ₂ The pressure is 0.55～0.6MPa, the temperature is -53～-55℃, the pressure of the liquid _CO2 at the outlet of the liquid centrifugal pump (10) is 14-15MPa, the temperature is -40～-50℃, the circulating water heater (11) The pressure of gaseous CO ₂ at the outlet of the exothermic side is 14-15MPa and the temperature is 10-15 ℃, the pressure of gaseous CO ₂ at the outlet of the exothermic side of the heater is 14-15MPa, the temperature is 140-155 ℃, the gaseous CO 2 at the outlet of the expander is 14-15MPa ₂ The pressure is 1～1.2MPa, the temperature is 65～75℃, the gaseous CO ₂ pressure is 1～1.2MPa, the temperature is 20～25℃, the heat release side of the condenser (16) The water temperature at the outlet is 20-65°C, and the water temperature at the outlet of the heat-absorbing side of the circulating water heater (11) is 15-20°C. 8. a kind of closed cycle energy storage method according to claim 7, is characterized in that: The compressor comprises a primary compressor (1) and a secondary compressor (3), the cooler comprises a primary interstage cooler (2) and a secondary interstage cooler (4), and the primary compressor (1) ) outlet is connected to the inlet of the heat-absorbing side of the primary interstage cooler (2), the heat-absorbing side outlet of the primary inter-stage cooler (2) is connected to the inlet of the secondary compressor (3), and the outlet of the secondary compressor (3) It is connected to the inlet of the heat absorption side of the secondary interstage cooler (4), and the outlet of the heat absorption side of the secondary interstage cooler (4) is connected to the inlet of the low temperature expansion and liquefaction system; the inlet of the heat storage tank (8) is connected to the first interstage cooling The cold outlet of the cooler (2) and the secondary interstage cooler (4) are connected, the outlet of the heat storage tank (8) is connected with the hot inlet of the heater, and the hot outlet of the heater is connected with the inlet of the cold storage tank (9), The outlet of the cold storage tank (9) is communicated with the cold inlets of the primary interstage cooler (2) and the secondary interstage cooler (4); The pressure of gaseous CO ₂ at the outlet of the primary compressor (1) is 2.88-3 MPa, and the temperature is 140-155 °C _; 15～25℃, the gaseous _CO2 pressure at the outlet of the secondary compressor (3) is 14～15MPa, the temperature is 150～160℃, the gaseous _CO2 pressure at the outlet of the heat absorption side of the secondary interstage cooler (4) is 14 ～15MPa, and the temperature is 50～60℃. 9. A closed-cycle energy storage method according to claim 7, characterized in that: the expander comprises a primary expander (13) and a secondary expander (15), and the heater comprises a primary heater (12) ) and the secondary heater (14), the cold outlet of the circulating water heater (11) is connected to the cold inlet of the primary heater (12), and the cold outlet of the primary heater (12) is connected to the primary expander (13). ), the outlet of the primary expander (13) is connected to the cold inlet of the secondary heater (14), and the cold outlet of the secondary heater (14) is connected to the inlet of the secondary expander (15). The outlet of the stage expander (15) is connected with the hot inlet of the condenser (16); the outlet of the heat storage tank (8) is communicated with the hot inlets of the primary heater (12) and the secondary heater (14), a The heat outlet of the primary heater (12) and the secondary heater (14) is communicated with the inlet of the cold storage tank (9); The pressure of gaseous _{CO 2} at the outlet on the exothermic side of the primary heater (12) is 14-15 MPa, and the temperature is 140-155° C. The pressure of the gaseous _CO2 at the outlet of the secondary expander (15) is 1-1.2MPa, and the temperature is 65-75°C. 10. A kind of closed cycle energy storage method according to claim 7, is characterized in that: The low-temperature expansion and liquefaction system includes a low-temperature expander (5), a first throttle valve (6) and a first liquid storage tank (7); the outlet of the heat-absorbing side of the cooler is connected to the inlet of the low-temperature expander (5), and the low-temperature expander (5) The outlet is connected to the first liquid storage tank (7), a first throttle valve (6) is arranged on the pipeline connecting the low temperature expander (5) to the first liquid storage tank (7), and the first liquid storage tank ( The outlet of 7) is connected to the inlet of the liquid centrifugal pump (10); the pressure of the liquid _CO2 at the outlet of the low temperature expander (5) is 1.2～1.5MPa, the temperature is -40～-60℃, and the outlet of the first throttle valve (6) The pressure of the liquid CO ₂ is 0.55～0.6MPa, and the temperature is -53～-55℃; The cooling and cold storage liquefaction system includes a deep cold accumulator (19) and a second liquid storage tank (21). The side outlet is connected to the inlet of the second liquid storage tank (21), the outlet of the second liquid storage tank (21) is connected to the inlet of the heat release side of the deep regenerator (19), and the connecting pipeline is provided with a second throttle valve (20) , the outlet of the heat release side of the deep regenerator (19) is connected to the inlet of the expander; the gaseous CO ₂ pressure of the inlet of the heat absorbing side of the deep regenerator (19) is 1-1.2MPa and the temperature is 20-25°C, and the deep regenerator (19) The outlet of the endothermic side is liquid CO ₂ , the pressure of the liquid CO ₂ is 0.9-1 MPa, and the temperature is -42--40° C. The pressure of the CO ₂ stored in the second liquid storage tank (21) is 1-1.2 MPa, and the temperature is -42～-40℃, the pressure of liquid _CO2 at the outlet of the second throttle valve (20) is 0.6～0.8MPa, the temperature is -38～-35℃, the gaseous _CO2 at the outlet of the heat release side of the deep regenerator (19) The pressure is 0.6 to 0.8 MPa and the temperature is 10 to 20°C.

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