Cold power generation system

Abstract

According to the cold power generation system, liquid gas in a liquid storage tank enters a low-boiling-point working medium condenser through a recooler, a gaseous low-boiling-point working medium discharged by a low-boiling-point working medium expansion machine is liquefied in the low-boiling-point working medium condenser, and then is gasified through a low-boiling-point working medium circulating pump and a low-boiling-point working medium evaporator; the gaseous working medium enters the low-boiling-point working medium expansion machine to do work through expansion, the generator is dragged to generate electricity, and the gaseous low-boiling-point working medium discharged from the low-boiling-point working medium expansion machine enters the low-boiling-point working medium condenser, so that a low-boiling-point working medium Rankine cycle loop is formed; gaseous gas from the low-boiling-point working medium condenser is divided into two paths, one path is output gas, the other path is gaseous backflow gas, and the gaseous backflow gas becomes liquid backflow gas through the compressor and the recooler and is conveyed to the liquid storage tank. Liquid gas is used as an energy storage medium, photovoltaic electricity and wind electricity can be efficiently absorbed or used for valley shifting and peak filling of an electric power system, and cold energy of the liquid gas is efficiently recycled and used for cold power generation and can be used as driving power of a carrier.

Description

Technical Field

[0001] The invention relates to a cold power generation system, in particular to a cold power generation system using liquid gas energy storage. Background Art

[0002] As important basic raw materials for modern industry, gas products have a wide range of applications.

[0003] In order to facilitate large-scale storage and transportation, gases are usually liquefied and turned into liquid gases to improve the efficiency of transportation and storage. When used, liquid gases such as LNG (liquefied natural gas), liquid air, liquid nitrogen, liquid oxygen, liquid hydrogen, liquid carbon dioxide, liquid ammonia, etc. are converted into room temperature gases. In this process, a large amount of available cold energy is released. At present, most of this cold energy has not been effectively utilized, wasting a lot of precious resources. Take LNG as an example: At present, most of the LNG cold energy utilization projects in the world are single-user, and there are very few multi-user integrated projects. So far, only about 20% of LNG cold energy has been utilized; the amount of cold energy utilized accounts for only about 8% of the total LNG cold energy. In the current utilization technology, except for the temperature of air separation utilization at -145 ~ -75℃, the cold temperature of other users is mostly not matched with the temperature distribution of cold energy from LNG gasification, that is, "high quality and low utilization", and the process has a large loss of available energy. For example, the current cold energy power generation is actually just a low-grade utilization of cold energy: such as the commonly used organic Rankine cycle power generation unit with propane as the working fluid, which is used to recover the cold energy released by converting liquefied natural gas at near normal pressure into gaseous natural gas at near normal pressure and temperature. The condensing temperature of the condenser is generally controlled at about -45℃, and the evaporating temperature of the evaporator is controlled at about 15℃. It is difficult to achieve energy-quality matching and recycling of high-grade cold energy at about -75 ~ -145℃.

[0004] Since photovoltaic and wind power generation are random and intermittent, and electricity has the characteristics of real-time balance of supply and demand and is difficult to store on a large scale, the large-scale grid-connected photovoltaic and wind power generation will aggravate the dual volatility and uncertainty on both the supply and demand sides of the power system, making system peak regulation difficult and bringing about a series of problems such as abandoned solar and wind power. Energy storage can smooth out the instability of photovoltaic and wind power generation and achieve a dynamic balance of electricity supply and demand.

[0005] The new energy power supply system will face problems such as mismatch between power supply and demand, and energy storage, virtual power plants, microgrids and other regulation methods are indispensable. Electric energy is a dynamic process energy that is not easy to store. It is mainly achieved through the power grid to achieve simultaneous production, transmission and consumption. The power generation method of new energy (such as wind power and solar energy) is greatly affected by weather conditions and has the characteristics of intermittent, volatility and instability. Large-scale application will have an impact on the stability of the power grid. In order to cope with the power generation characteristics of new energy power generation, regulation methods such as energy storage, virtual power plants, and microgrids will be widely used in the future. Therefore, the configuration of energy storage is indispensable in the future green power energy system, and the role of new energy storage in promoting the development and consumption of new energy and the safe and stable operation of the power system is gradually emerging.

[0006] Traditional vehicles such as cars, diesel vehicles, airplanes and ships use oil and gas as fuel to drive engines or internal combustion engines to provide driving power. The fuel combustion process will inevitably produce thermal pollution and other pollutants, such as nitrogen oxides, sulfur oxides brought into the fuel and produced during the combustion process, dioxins, etc., which will cause harm to people and the environment.

[0007] As a representative of new energy vehicles, pure electric vehicles have a strong development momentum and are driven by policies to replace gasoline and gas vehicles. However, pure electric vehicles currently have certain problems: the driving range is generally short, usually within 300 kilometers, which is significantly less than that of fuel and gas vehicles; the charging time is long and charging is not convenient; the battery life is limited, the number of charge and discharge times is limited, and it needs to be replaced regularly, and the recycling and disposal of batteries needs to be solved urgently; there are many batteries, and many battery modules are connected in series and parallel. If there is a cold solder joint between the battery welding points or joints, it is very easy to heat up, and the fire accident caused is difficult to rescue and has great harm.

[0008] The air-energy car reported in the report uses high-pressure air stored in a high-pressure gas tank as its power source. It is clean and environmentally friendly, but its energy storage density is low.

[0009] Therefore, it is worthwhile to study in depth how to recover the high-quality cold energy of liquid gas, how to use liquid gas to store energy and recover the cold energy of liquid gas for cold power generation, and even how to use liquid gas as a new energy carrier and use it as a driving power source. Summary of the invention

[0010] The purpose of the present invention is to solve the above-mentioned problems and provide a cold power generation system, which can be used to construct a storage-type cold power generation plant, can also be used to recover the cold energy of liquefied gas commonly used in factories, and can also use the stored liquefied gas to generate cold power and provide driving power for carriers such as automobiles, diesel vehicles, ships or aircraft.

[0011] A cold power generation system, the implementation process of which is as follows: The liquid gas in the liquid storage tank 3 enters the low-boiling-point working medium condenser 8 through the recooler 7, releases cold energy in the low-boiling-point working medium condenser 8, liquefies the gaseous low-boiling-point working medium 15 discharged from the low-boiling-point working medium expander 13, and then is gasified by the low-boiling-point working medium circulation pump 9 and the low-boiling-point working medium evaporator 10. The formed gaseous working medium enters the low-boiling-point working medium expander 13 to expand and do work, driving the generator 14 to generate electricity. The gaseous low-boiling-point working medium 15 discharged from the low-boiling-point working medium expander 13 enters the low-boiling-point working medium condenser 8 again to absorb cold energy and liquefy, thereby forming a low-boiling-point working medium Rankine cycle loop; the gaseous gas 16 coming out of the low-boiling-point working medium condenser 8 is divided into two paths: one path is the output gas 20, which is discharged into the atmosphere or output as a product, process gas, etc., and the other path is the gaseous reflux gas 17. The gaseous reflux gas 17 is liquefied by the compressor 18 and the recooler 7 to become the liquid reflux gas 19 and is transported to the liquid storage tank 3.

[0012] The liquid gas in the liquid storage tank 3 serves as an energy storage medium or an energy carrier.

[0013] The low boiling point working fluid expander 13 is a scroll type, screw type, centrifugal type, turbine type or piston type expander.

[0014] The liquid gas is liquid air, liquid hydrogen, liquid oxygen, liquid nitrogen, liquid argon, liquid oxygen-enriched air, liquid nitrogen-enriched air or liquid carbon dioxide. The oxygen-enriched air means that the oxygen component in the gas is higher than the oxygen component content in the air, and the nitrogen-enriched air means that the nitrogen component in the gas is higher than the nitrogen component content in the air.

[0015] The recooler 7 recovers high-quality cold energy of the liquid gas output from the liquid storage tank 3, transmits it to the reflux gas 17 pressurized by the compressor 18, and then transports it to the low-boiling point working medium condenser 8. The gaseous reflux gas 17 is liquefied in the recooler 7 and then transported to the liquid storage tank 3.

[0016] The low-boiling-point working fluid in the low-boiling-point working fluid Rankine cycle loop has a boiling point of less than -10°C under standard atmospheric pressure, such as CN2013100293794 Steam Rankine-Low-Boiling-Point Working Fluid Rankine Combined Cycle Power Generation Device, CN2013100293775 Extraction Type Steam Rankine-Low-Boiling-Point Working Fluid Rankine Combined Cycle Power Generation Device, etc., which provide further descriptions of low-boiling-point working fluids. In the application, propane is used as the working fluid of the low-boiling-point working fluid Rankine cycle loop.

[0017] The heating medium of the low-boiling-point working medium evaporator 10 is a heat medium 11, which can be selected from air, water or seawater at room temperature. The liquid low-boiling-point working medium is heated in the low-boiling-point working medium evaporator 10 to be vaporized. The refrigerant 12 with reduced temperature coming out of the low-boiling-point working medium evaporator 10 can be used as a cold source to supply cold to cold units such as cold storage, refrigeration air conditioners or other cold users.

[0018] The generator 14 is an AC generator or a DC generator. When a DC generator is used, the battery 21 can be charged directly; when an AC generator is used, the battery can be charged via an AC / DC converter.

[0019] A vaporizer 4 is provided: one end of the vaporizer 4 is connected to the bottom liquid side of the liquid storage tank 3 through a pipeline, and the other end is connected to the top gas side of the liquid storage tank 3 through a pipeline; when the liquid gas stored in the liquid storage tank 3 releases energy, the pressure in the liquid storage tank 3 decreases, and the liquid gas in the vaporizer 4 is heated to be vaporized and enter the top gas space of the liquid storage tank 3, thereby maintaining the pressure in the liquid storage tank 3 stable.

[0020] The heater in the gasifier 4 is made of metal coils or finned tubes, etc. The heating medium is preferably air, and the heating medium should contain less water to avoid ice clogging of the heater due to improper operation.

[0021] A pressure relief valve 5 is provided to regulate the pressure increase caused by the heat absorption of the liquid gas in the liquid storage tank 3 when the equipment is shut down, so as to prevent overpressure.

[0022] The output gas 20 is lower than the ambient temperature and can be used as a cold source to supply cold to a cold unit.

[0023] A gas liquefaction unit 2 is provided: a single-component or multi-component gas 1 is passed through the gas liquefaction unit 2 to produce liquid gas, which is then sent to a liquid storage tank 3.

[0024] The gas liquefaction unit 2 adopts the well-known oxygen generator principle and gas compression refrigeration liquefaction principle to perform gas liquefaction operation, such as CN2013100302473-An air separation device for isobaric separation of air to produce oxygen and nitrogen, CN2013100309237-An air separation device for isobaric separation of oxygen and nitrogen, etc., which provide technical approaches for producing liquid air, liquid oxygen, etc. The gas liquefaction unit 2 includes gas compression and cooling processes, as well as gas purification and purification processes.

[0025] Equipment, pipelines, instruments, valves, cold preservation, bypass facilities with regulating functions, etc. not described in the present invention are matched with reference to or in accordance with mature technologies in well-known traditional processes.

[0026] The equipment and pipelines in the present invention adopt necessary heat recovery, cooling recovery, quality recovery and other measures.

[0027] Parts not mentioned in the present invention, such as safety accessories, automatic control, etc., are matched with existing well-known technologies, that is, existing mature, reliable and reasonable technical measures are applied to this system.

[0028] Compared with the prior art, the present invention has the following advantages: 1. Compared with the existing liquid air energy storage thermal power station, the present invention retains the advantages of the liquid air energy storage thermal power station, provides a new energy storage type cold power generation system, adopts the reflux gas cooling liquefaction to recover the high-quality cold energy of liquid gas, and is an improvement on the traditional cold power generation technology; 2. Compared with the prior art, the present invention can combine the characteristics of the energy storage type cold power generation system with abundant surplus cold energy, optimize with large cold storage, central air conditioning or the system using cold source for seawater desalination, or use it as the cold source of the centralized cooling system to realize the cogeneration of cold and electricity; 3. Compared with the prior art, the cold power generation system of the present invention can effectively absorb photovoltaic power and wind power or be used for "shifting valleys and filling peaks" to optimize operation. The raw material can be selected from the extremely abundant source of ambient air, which is clean and environmentally friendly. It can also produce liquid oxygen, nitrogen and liquid nitrogen according to market demand, thereby improving the comprehensive advantages of the cold power generation system; 4. Compared with the prior art, the present invention can use liquid air as an energy carrier for cold power generation to provide driving power for the carrier; 5. Compared with the prior art, the present invention can be used for efficient recovery and utilization of liquefied gas cold energy; 6. The energy storage type cold power generation system of the present invention can be conveniently used as a distributed cold power generation station for use by people in wartime. As long as there is liquid air transferred, the cold power generation set can be started using the backup power supply to provide electricity and cooling, and can provide high-quality air resources for breathing space in air defense facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the process flow of the cold power generation system of the present invention.

[0030] Figure 1 In: 1-single component or multi-component gas, 2-gas liquefaction unit, 3-liquid storage tank, 4-vaporizer, 5-pressure relief valve, 7-recooler, 8-low boiling point working fluid condenser, 9-low boiling point working fluid circulation pump, 10-low boiling point working fluid evaporator, 11-heat medium, 12-refrigerant (can be used as cooling medium), 13-low boiling point working fluid expander, 14-generator, 15-gaseous low boiling point working fluid, 16-gaseous gas, 17-reflux gas, 18-compressor, 19-liquid reflux gas, 20-output gas, 21-battery. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Embodiment 1: like Figure 1 As shown, a cold power generation system, the implementation process of which is as follows: The liquid gas in the liquid storage tank 3 enters the low-boiling-point working medium condenser 8 through the recooler 7, releases cold energy in the low-boiling-point working medium condenser 8, liquefies the gaseous low-boiling-point working medium 15 discharged from the low-boiling-point working medium expander 13, and then is gasified by the low-boiling-point working medium circulation pump 9 and the low-boiling-point working medium evaporator 10. The formed gaseous working medium enters the low-boiling-point working medium expander 13 to expand and do work, driving the generator 14 to generate electricity. The gaseous low-boiling-point working medium 15 discharged from the low-boiling-point working medium expander 13 enters the low-boiling-point working medium condenser 8 again to absorb cold energy and liquefy, thereby forming a low-boiling-point working medium Rankine cycle loop; the gaseous gas 16 coming out of the low-boiling-point working medium condenser 8 is divided into two paths: one path is the output gas 20, which is discharged into the atmosphere or output as a product, process gas, etc., and the other path is the gaseous reflux gas 17. The gaseous reflux gas 17 is liquefied by the compressor 18 and the recooler 7 to become the liquid reflux gas 19 and is transported to the liquid storage tank 3.

[0033] The liquid gas is liquid air.

[0034] The liquid air in the liquid storage tank 3 is the energy storage medium.

[0035] The recooler 7 recovers high-quality cold energy of the liquid gas output from the liquid storage tank 3, transmits it to the reflux gas 17 pressurized by the compressor 18, and then transports it to the low-boiling point working medium condenser 8. The gaseous reflux gas 17 is liquefied in the recooler 7 and then transported to the liquid storage tank 3.

[0036] The low boiling point working fluid is propane.

[0037] The heating medium of the low-boiling-point working medium evaporator 10 is a heat medium 11. Air at room temperature is selected to heat the liquid low-boiling-point working medium in the low-boiling-point working medium evaporator 10 to vaporize it. The refrigerant 12 with reduced temperature coming out of the low-boiling-point working medium evaporator 10, i.e., cold air 12, can be used as a cold source to supply cold to cold units such as cold storages, refrigeration air conditioners or other cold users.

[0038] When the generator 14 is a DC generator, the battery 21 is directly charged.

[0039] A vaporizer 4 is provided: one end of the vaporizer 4 is connected to the bottom liquid side of the liquid storage tank 3 through a pipeline, and the other end is connected to the top gas side of the liquid storage tank 3 through a pipeline; when the liquid gas stored in the liquid storage tank 3 releases energy, the pressure in the liquid storage tank 3 decreases, and the liquid gas in the vaporizer 4 is heated to be vaporized and enter the top gas space of the liquid storage tank 3, thereby maintaining the pressure in the liquid storage tank 3 stable.

[0040] The heater in the gasifier 4 is made of metal coils or finned tubes, etc., and the heating medium is air.

[0041] A pressure relief valve 5 is provided to regulate the pressure increase caused by the heat absorption of the liquid gas in the liquid storage tank 3 when the equipment is shut down, so as to prevent overpressure.

[0042] The output gas 20 is lower than the ambient temperature and can be used as a cold source to supply cold to a cold unit.

[0043] A gas liquefaction unit 2 is provided: a single-component or multi-component gas 1 is passed through the gas liquefaction unit 2 to produce liquid gas, which is then sent to a liquid storage tank 3. The gas liquefaction unit 2 is an air liquefaction unit.

[0044] The gas liquefaction unit 2 adopts the well-known oxygen generator principle and gas compression refrigeration liquefaction principle to perform gas liquefaction operation, such as CN2013100302473-An air separation device for isobaric separation of air to produce oxygen and nitrogen, CN2013100309237-An air separation device for isobaric separation of oxygen and nitrogen, etc., which provide technical approaches for producing liquid air. The gas liquefaction unit 2 includes air compression and cooling processes, as well as air purification and purification processes.

[0045] Equipment, pipelines, instruments, valves, cold preservation, bypass facilities with regulating functions, etc. not described in the present invention are matched with reference to or in accordance with mature technologies in well-known traditional processes.

[0046] The equipment and pipelines in the present invention adopt necessary heat recovery, cooling recovery, quality recovery and other measures.

[0047] Parts not mentioned in the present invention, such as safety accessories, automatic control, etc., are matched with existing well-known technologies, that is, existing mature, reliable and reasonable technical measures are applied to this system.

[0048] Although the present invention has been disclosed as above with preferred embodiments, they are not intended to limit the present invention. Anyone familiar with the art can make various changes or modifications without departing from the spirit and scope of the present invention, which also belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the definition of the claims of this application.

Claims

1. A cold power generation system, characterized in that: The liquid gas in the liquid storage tank (3) enters the low-boiling-point working medium condenser (8) through the recooler (7), and the gaseous low-boiling-point working medium (15) discharged from the low-boiling-point working medium expander (13) is liquefied in the low-boiling-point working medium condenser (8), and then gasified through the low-boiling-point working medium circulation pump (9) and the low-boiling-point working medium evaporator (10). The resulting gaseous working medium enters the low-boiling-point working medium expander (13) to expand and perform work, driving the generator (14) to generate electricity, thereby generating electricity from the low-boiling-point working medium expansion. The gaseous low-boiling-point working medium (15) discharged from the machine (13) then enters the low-boiling-point working medium condenser (8), thereby forming a low-boiling-point working medium Rankine cycle loop; the gaseous gas (16) discharged from the low-boiling-point working medium condenser (8) is divided into two paths: one path is the output gas (20), and the other path is the gaseous reflux gas (17); the gaseous reflux gas (17) passes through the compressor (18) and the recooler (7) to become the liquid reflux gas (19), and is transported to the liquid storage tank (3).

2. The cold power generation system according to claim 1, characterized in that: A vaporizer (4) is provided: one end of the vaporizer (4) is connected to the bottom liquid side of the liquid storage tank (3) through a pipeline, and the other end is connected to the top gas side of the liquid storage tank (3) through a pipeline; when the liquid gas stored in the liquid storage tank (3) releases energy, the pressure in the liquid storage tank (3) decreases, and the liquid gas in the vaporizer (4) is heated to vaporize and enter the top gas space of the liquid storage tank (3), thereby maintaining the pressure in the liquid storage tank (3) stable.

3. The cold power generation system according to claim 1, characterized in that: The liquid gas is liquid air, liquid hydrogen, liquid oxygen, liquid nitrogen, liquid argon, liquid oxygen-enriched air, liquid nitrogen-enriched air or liquid carbon dioxide.

4. The cold power generation system according to claim 1, characterized in that: The refrigerant (12) with reduced temperature coming out of the low-boiling-point working fluid evaporator (10) is used as a cold source to supply cold air to the cold unit.

5. The cold power generation system according to claim 1, characterized in that: The output gas (20) is used as a cold source to supply cold to a cold unit.

6. The cold power generation system according to claim 1, characterized in that: A gas liquefaction unit (2) is provided: a single-component or multi-component gas (1) is passed through the gas liquefaction unit (2) to obtain liquid gas, which is then sent to a liquid storage tank (3).

7. The cold power generation system according to claim 6, characterized in that: The gas liquefaction unit (2) includes an air compression and cooling process, and also includes an air purification and refining process.

8. The cold power generation system according to claim 1, characterized in that: The generator (14) is an AC generator or a DC generator. When a DC generator is used, the storage battery (21) is charged directly. When an AC generator is used, the storage battery (21) is charged via an AC / DC conversion device.

9. The cold power generation system according to claim 1, characterized in that: The low boiling point working fluid expander (13) is a scroll type, screw type, centrifugal type, turbine type or piston type expander.

10. The cold power generation system according to claim 1, characterized in that: The low-boiling-point working fluid in the low-boiling-point working fluid Rankine cycle loop has a boiling point of less than -10°C under standard atmospheric pressure.

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