CN116804381A - Liquid air energy storage power generation system and equipment - Google Patents
Liquid air energy storage power generation system and equipment Download PDFInfo
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- CN116804381A CN116804381A CN202310784727.2A CN202310784727A CN116804381A CN 116804381 A CN116804381 A CN 116804381A CN 202310784727 A CN202310784727 A CN 202310784727A CN 116804381 A CN116804381 A CN 116804381A
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Abstract
The invention belongs to the technical field of liquid air energy storage power generation, and in particular relates to a liquid air energy storage power generation system and equipment, wherein the system comprises the following components: the air compression liquefaction module, the air gasification heating module and the generator module are connected in sequence; the air compression and liquefaction module comprises a compressor unit, a first heat exchange unit and an air liquefaction storage unit which are connected in sequence, and is used for compressing gaseous air into liquid state and storing energy; the air gasification heating module comprises a low-temperature pump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are connected in sequence, and is used for converting liquid air into gas; the generator module comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module is used for generating electric energy. The low-quality heat in the environment is recovered at low temperature through the gasification of liquid air, and the conversion efficiency of air energy storage is improved through energy recycling.
Description
Technical Field
The invention belongs to the technical field of liquid air energy storage power generation, and particularly relates to a liquid air energy storage power generation system and equipment.
Background
The energy is necessary production and living data in modern society, the stable supply of energy is ensured, and the continuous improvement of the energy utilization efficiency is an important foundation for national economic development and social progress. The energy source of China is relatively deficient, the energy source of people is in a lower level in the world, and along with the industrialization, the city and the rapid development of electric vehicles in China, the power load is larger and larger, and the development of renewable energy sources is the need of clean and environment-friendly and the need of energy source demand development. With the increase of the utilization of renewable energy sources, the random and fluctuating large-scale new energy source is connected into the power grid, so that larger disturbance is brought to the traditional power grid, the change of a power supply structure is caused, and the application requirement of the power grid for peak-to-peak frequency modulation is increased. The distributed power supply is connected with the development of the micro-grid, and the requirements of the development of the electric automobile on a matched energy storage system are continuously enhanced. New requirements are also being made by military, industrial and civilian use based on improving the reliability of electricity usage. Thus, the development of energy storage systems will become a rigid requirement for the power industry.
The energy storage technology mainly comprises pumped storage, compressed air storage and electrochemical storage. The pumped storage technology is mature, the efficiency is high, but the problems of geographical position limitation and the like exist, and the large-scale popularization is difficult; the electrochemical energy storage technology has the advantages of quick response, small volume, short construction period, short overall service life, large industrial pollution and the like; the liquid compressed air energy storage technology has the characteristics of long service life, small environmental pollution, low operation and maintenance cost and the like, and has large-scale popularization and application potential.
The efficiency of the liquid air energy storage power generation system is closely related to whether the energy of the whole system can be fully utilized, and then the efficiency and the energy utilization rate of the liquid air energy storage power generation system in the prior art are low.
Based on the above, how to provide a liquid air energy storage power generation system, so as to effectively improve the efficiency of liquefied air energy storage power generation is a problem to be solved.
Disclosure of Invention
In order to solve the problem of low energy utilization rate of the liquefied air energy storage power generation system in the prior art, the embodiment of the invention provides the following technical scheme.
In a first aspect, the present invention provides a liquid air energy storage power generation system comprising: the air compression liquefaction module, the air gasification heating module and the generator module are connected in sequence;
the air compression and liquefaction module comprises an air compressor unit, a first heat exchange unit and an air liquefaction storage unit which are connected in sequence, wherein the air compression and liquefaction module is used for compressing gaseous air into liquid state and storing energy;
the air gasification heating module comprises a low-temperature pump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are connected in sequence, and is used for converting liquid air into gas;
The generator module comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module is used for generating electric energy.
Further, the air compressor unit comprises a first-stage low-pressure ratio compressor, a second-stage low-pressure ratio compressor and a high-pressure ratio compressor which are sequentially connected, and air compressed by the first-stage low-pressure ratio compressor and the second-stage low-pressure ratio compressor enters the high-pressure ratio compressor and the pressure and the temperature of the air are increased by the high-pressure ratio compressor.
Further, the air liquefaction storage unit includes: the cold water in the cold water tank and the compressed high-temperature air are subjected to heat exchange to be changed into hot water, and the hot water enters the hot water tank to store heat energy.
Further, the first heat exchange unit comprises a first heat exchanger, a second heat exchanger and a third heat exchanger, air at the outlet of the first-stage low-pressure-ratio compressor enters the first heat exchanger through a heat medium inlet of the first heat exchanger, a heat medium outlet of the first heat exchanger is connected with a hot water tank, a refrigerant inlet of the first heat exchanger is connected with a cold water tank, a refrigerant outlet of the first heat exchanger is connected with the second-stage low-pressure compressor, air at the outlet of the second-stage low-pressure compressor enters the second heat exchanger through a heat medium inlet of the second heat exchanger, and a heat medium outlet of the second heat exchanger is connected with the hot water tank through the third heat exchanger.
Further, the third heat exchanger is connected with the expansion machine, and after the high-pressure air expands and works through the expansion machine, the high-pressure air loses pressure to form low-temperature gas which enters the liquefaction tank.
Further, the air compression liquefaction module further comprises a high-temperature high-pressure air cooling unit and a cold-heat exchange energy circulation unit, wherein the high-temperature high-pressure air cooling unit is connected with the cold-heat exchange energy circulation unit, and the cold-heat exchange energy circulation unit is connected with the air liquefaction storage unit.
Further, the second heat exchange unit includes four heat exchangers a, b, c and d connected in sequence.
Further, the second heat exchange unit further comprises a low-temperature antifreeze liquid groove and a high-temperature antifreeze liquid groove, the liquid air is pumped into the heat exchanger a through the low-temperature pump to exchange heat with the high-temperature antifreeze liquid in the high-temperature antifreeze liquid groove, so that the liquid air is quickly gasified and heated, and the high-temperature antifreeze liquid flows into the low-temperature antifreeze liquid groove after the temperature of the high-temperature antifreeze liquid drops to a preset temperature.
Further, the generator module further comprises a turbine, high-temperature and high-pressure air enters a combustion chamber of the gas turbine, the high-temperature and high-pressure air is heated to a preset temperature value under the condition of burning oil, and the high-temperature and high-pressure air enters the turbine to expand and do work, so that the air energy is converted into mechanical energy, and then the generator is driven to convert the mechanical energy into electric energy.
In a second aspect, the present invention provides a liquid air energy storage power generation apparatus comprising: a liquid air energy storage power generation system as described in any of the first aspects.
It will be appreciated that the present invention provides a liquid air energy storage power generation system comprising: the air compression liquefaction module, the air gasification heating module and the generator module are connected in sequence; the air compression and liquefaction module comprises a compressor unit, a first heat exchange unit and an air liquefaction storage unit which are connected in sequence, and is used for compressing gaseous air into liquid state and storing energy; the air gasification heating module comprises a low-temperature pump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are connected in sequence, and is used for converting liquid air into gas; the generator module comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module is used for generating electric energy. Low-quality heat in the environment is recovered at low temperature through gasification of liquid air, and the conversion efficiency of air energy storage is improved through energy recycling; meanwhile, the energy conversion efficiency of the gas turbine can be obviously improved by improving the pressure of the gas entering the gas turbine, so that the air energy storage conversion efficiency and the Brownian cycle efficiency of the gas turbine are improved simultaneously, and the energy conversion efficiency is further improved by generating power through combined cycle with a waste heat boiler and a steam turbine.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a liquid air energy storage power generation system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a liquid air energy storage power generation system according to another embodiment of the present invention;
FIG. 3 is a schematic illustration of a gas turbine cycle process provided in accordance with one embodiment of the present invention;
FIG. 4 is a schematic diagram of fuel gas temperature and cycle efficiency provided by an embodiment of the present invention;
FIG. 5 is a schematic view of a prior art gas turbine engine configuration provided in accordance with an embodiment of the present invention;
FIG. 6 is a schematic illustration of fuel consumption rates provided by one embodiment of the present invention;
FIG. 7 is a schematic diagram of the work to pressure ratio relationship provided by one embodiment of the present invention;
FIG. 8 is a graphical representation of effective work versus required air flow for an intake pressure provided by one embodiment of the present invention;
FIG. 9 is a schematic diagram of the relationship between single machine efficiency and intake pressure according to one embodiment of the present invention;
FIG. 10 is a schematic diagram of air flow versus heat efficiency of a combustion engine provided by one embodiment of the present invention;
FIG. 11 is a schematic diagram of fuel consumption versus thermal efficiency of a combustion engine provided by an embodiment of the present invention;
FIG. 12 is a graph illustrating intake pressure versus energy efficiency ratio according to one embodiment of the present invention.
Summarizing the reference numerals:
101. an air compression liquefaction module; 102 an air gasification heating module; 103. and a generator module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, based on the examples herein, which are within the scope of the invention as defined by the claims, will be within the scope of the invention as defined by the claims.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a liquid air energy storage power generation system according to an embodiment of the present invention, as shown in fig. 1, including:
an air compression liquefaction module 101, an air gasification temperature raising module 102 and a generator module 103 which are connected in sequence.
The air compression and liquefaction module 101 comprises an air compressor unit, a first heat exchange unit and an air liquefaction storage unit which are sequentially connected, and the air compression and liquefaction module 101 is used for compressing gaseous air into liquid state and storing energy.
The air compressor unit is used for compression, and the purpose is to obtain higher air pressure and temperature under the condition of high-efficiency compression.
The air gasification temperature-raising module 102 comprises a cryopump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are sequentially connected, and the air gasification temperature-raising module 102 is used for converting liquid air into gas.
The liquid air energy storage has the following maximum characteristics: the gasification temperature of the liquid air is-196 ℃, and a great amount of cold existsThe heat exchange can be carried out with the antifreeze, the temperature of the antifreeze is reduced to be close to the freezing point, and the air temperature is increased through the heat exchange, which is an important ring for improving the system efficiency; the liquid air is pumped into the second heat exchange unit by a cryogenic pump, the air is vaporized rapidly by recovering the stored heat source, and the pipeline pressure is regulated by a pressure and flow control unit to form high pressure air.
The second heat exchange unit comprises four heat exchangers a, b, c and d which are sequentially connected.
In some embodiments, the second heat exchange unit further includes a low-temperature antifreeze liquid tank and a high-temperature antifreeze liquid tank, the liquid air is pumped into the heat exchanger a through a low-temperature pump to exchange heat with the high-temperature antifreeze liquid in the high-temperature antifreeze liquid tank, so that the liquid air is gasified and warmed rapidly, and the high-temperature antifreeze liquid flows into the low-temperature antifreeze liquid tank after the temperature of the high-temperature antifreeze liquid is reduced to a preset temperature.
The generator module 103 comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module 103 is used for generating electric energy.
The high-temperature high-pressure air enters a combustion chamber of the gas turbine, the air is heated to a set temperature under the condition of burning oil (gas), and the control unit drives the generator module to convert mechanical energy into electric energy.
The exhaust-heat boiler and the power generation are combined, and the exhaust-gas outlet is additionally provided with a non-energy-supplementing exhaust-heat boiler due to the fact that the temperature of exhaust gas of the gas turbine is higher, so that the energy conversion efficiency is improved. The flue gas discharged from the waste heat boiler is reintroduced into the heat exchanger, subjected to heat exchange with high-pressure air, and finally discharged at normal temperature. Thereby achieving the effects of recovering energy to the maximum extent and improving the energy conversion efficiency.
The liquid air energy storage power generation system has the advantages that:
(1) The energy storage medium is air, the medium for generating electricity is also air, and the discharged medium is also air, so that the energy storage medium has no influence on the environment.
(2) The liquid air can be stored for a long time at normal temperature and low pressure, and the storage is safe and reliable and the loss is small.
(3) High energy density of 700m 3 Is compressed and liquefied into 1m 3 The liquid air of the solar energy storage system is high in energy density, small in storage space, small in occupied construction land and strong in popularization when being used for energy storage and power generation.
(4) The gasification temperature of the liquid air is-196 ℃, and the liquid air has high coldCan be used for recovering low-quality heat, thereby improving the energy conversion efficiency and achieving the effects of water and energy conservation.
(5) The comparison of the various energy storage modes is shown in table 1.
Table 1: comparison of various energy storage modes
Pumped storage and compressed air energy storage are energy-type energy storage technologies meeting the requirement of large-scale peak shaving. Pumped storage is limited by geographical conditions and constraints of water resources; compressed air energy storage technology is evolving towards high efficiency, low cost and no geographic condition limitation.
(6) The three states of air energy storage are compared as shown in table 2.
Table 2: three state comparison of air energy storage
The cryogenic liquefied air energy storage technology has the advantages that air is stored in a low-pressure, low-temperature and liquid state, and the energy density is high; the low-pressure tank body has good safety and is not limited by geographic positions; the expected efficiency is 70% -80%, the better the energy supplementing system is designed, the higher the conversion efficiency is, and the application prospect is good.
The technical key points of the liquefied air energy storage power generation system are as follows:
1. the investment cost of the control system is increased as much as possible, and the air liquefying efficiency is improved;
2. is cold by fully utilizing liquid air gasificationLow-quality heat instant heating discharged by high-energy enterprises such as power plants, steel plants and chemical plants>Exchange is performed to form high-pressure hot gas, thereby achieving high conversion efficiency. Therefore, the recovery and storage of heat energy and cold energy must be of great concern in the design of liquid air power generation systems.
It can be understood that the liquid air energy storage power generation system provided by the invention comprises: the air compression liquefaction module, the air gasification heating module and the generator module are connected in sequence; the air compression and liquefaction module comprises a compressor unit, a first heat exchange unit and an air liquefaction storage unit which are connected in sequence, and is used for compressing gaseous air into liquid state and storing energy; the air gasification heating module comprises a low-temperature pump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are connected in sequence, and is used for converting liquid air into gas; the generator module comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module is used for generating electric energy. Low-quality heat in the environment is recovered at low temperature through gasification of liquid air, and the conversion efficiency of air energy storage is improved through energy recycling; meanwhile, the energy conversion efficiency of the gas turbine can be obviously improved by improving the pressure of the gas entering the gas turbine, so that the air energy storage conversion efficiency and the Brownian cycle efficiency of the gas turbine are improved simultaneously, and the energy conversion efficiency is further improved by generating power through combined cycle with a waste heat boiler and a steam turbine.
As a further improvement of the above system, in one embodiment, referring to fig. 2, fig. 2 is a schematic structural diagram of a liquid air energy storage power generation system according to another embodiment of the present invention. As shown in fig. 2, the air compressor unit includes a first low-pressure ratio compressor, a second low-pressure ratio compressor and a high-pressure ratio compressor connected in sequence, and air compressed by the first low-pressure ratio compressor and the second low-pressure ratio compressor enters the high-pressure ratio compressor and the pressure and the temperature of the air are increased by the high-pressure ratio compressor.
In order to compress low-temperature low-pressure air into high-temperature high-pressure gaseous air, the first two stages are low-pressure ratio compressors, and the later stage is a high-pressure ratio compressor, so that higher air pressure and temperature are obtained under the condition of high-efficiency compression.
According to the model design, the compression system adopts three-stage compression, and the compression ratio is 67.3 times; the outlet pressure reaches 6.8MPa, heat conduction oil is used as a cooling medium, the cooling oil groove and the hot oil groove are separated, compressed air is cooled through the cooling oil groove in the air compression process, heat is stored in the hot oil groove, and the heat storage temperature is 280-300 ℃; after compressed air is compressed in the third stage, the compressed air enters the second-stage heat exchanger, the temperature of the compressed air is reduced through cold water in the low-temperature cold water tank, and the compressed air enters the liquefaction tank for liquefaction, so that the efficiency of air compression and liquefaction is effectively improved; the exhaust gas of the liquefying tank is returned to the inlet of the compressor for cyclic compression.
As a further improvement of the above embodiments, in some embodiments, the air liquefaction storage unit includes: the cold water in the cold water tank and the compressed high-temperature air are subjected to heat exchange to be changed into hot water, and the hot water enters the hot water tank to store heat energy.
In the process of compressing air, high compression efficiency is obtained, and compression heat is collected. Therefore, a cold water tank and a hot water tank are adopted, cold water in the cold water tank is used for respectively cooling air compressed by the first-stage low-pressure ratio compressor and the second-stage low-pressure ratio compressor, so that the temperature of air entering the next-stage compressor is reduced, the compression efficiency is improved, and hot water flows into the hot water tank;
the air compressed by the two stages of low-pressure ratio enters a high-pressure ratio compressor 3; the pressure and the temperature of the air are increased through a high-pressure ratio compressor, then the high-temperature and high-pressure air is cooled by using heat conduction oil, and the high-temperature air is stored for expansion and heating of liquid air;
the cold water in the cold water tank exchanges heat with the high-temperature air in the compression process through the first heat exchange unit, and the hot water enters the hot water tank to store heat.
In fig. 2, cold water in the cold water tank exchanges heat with high-temperature air in the compression process (through the heat exchangers (1) and (2)), and hot water enters the hot water tank to store heat. And through the heat exchanger Heat exchange with the low-temperature expansion air is performed, and heat is transferred to the expansion air, so that the temperature of the expansion air is increased. Cold and hot water tanks and heat exchangers (1), (2) and +.>Forming an energy circulation system, wherein the numbers 1 and 2 marked in fig. 2 are the water flow directions of the water inlet and the water outlet;
wherein, cold and hot oil groove for heat conduction, heat exchanger (3) andthe high-temperature high-pressure air cooling system and the cold-heat exchange energy circulating system are formed, and the air is compressed by two stages and then compressed by one stage of high-pressure ratio, so that the temperature and the pressure are further increased. The purpose of the air rising is to store the temperature by means of a heat exchanger (3) and then by means of a heat exchanger +.>Air for expansion work is exchanged to raise the temperature of the expanded air, so as to achieve the purpose of raising energy storage conversion efficiency. Another object is to achieve an improved efficiency of air liquefaction by increasing the pressure of the compressed air to increase the saturation temperature of air liquefaction;
wherein the cold and hot antifreeze liquid tank, the heat exchangers (4), (5) andand a cold-heat exchange energy circulation system for forming an air liquefaction process and a liquid air gasification expansion process. The high-temperature high-pressure air and the antifreeze cold-storage low-temperature liquid flow in opposite directions, and heat exchange is carried out through the heat exchangers (4) and (5). The gas inlet of the expander is selected between the heat exchangers (4) and (5), and the temperature of the gas at the inlet of the expander is controlled by the design of the exchange power of the heat exchangers (4) and (5), so that the requirements that the expansion working efficiency of the expander is highest and the outlet temperature (entering the air liquefying tank (6)) after the expansion of the air is lower than the air liquefying saturation temperature are met. And the gas cooled by the heat exchanger (5) enters the air liquefying tank (6) for further cooling and then starts to liquefy. The low-temperature gas of the liquid-air separated gas is returned to the inlet of the air compressor 1 for cyclic compression.
Wherein a throttle valve is arranged between the heat exchanger (5) and the liquefaction tank (6), the liquefied air is throttled and expanded by the throttle valve, and the liquefaction efficiency is improved by adopting a throttling and expanding dual system with an expander and the throttle valve.
The high-pressure air expansion liquefaction system is characterized in that after expansion work is performed on the high-pressure air by an expander, low-temperature gas is formed after the air is decompressed and enters a liquefaction tank (6), and the low-temperature gas and the low-temperature high-pressure gas cooled by a heat exchanger (5) are subjected to heat exchange, so that the air is liquefied, and the saturated temperature of the air liquefaction is improved due to the fact that the pressure of the liquefied air is higher, and the air liquefaction efficiency is improved;
wherein, cryopump, air-vent valve, pressure and flow control system, heat exchangerForming a liquid air gasification temperature-rise and pressure-rise system; liquid air is pumped into the heat exchanger by means of a cryopump>Heat exchange is carried out with the high-temperature antifreeze, so that the liquid air is gasified and heated rapidly, and the antifreeze is cooled to the design temperature and flows into the antifreeze low-temperature storage tank (for air liquefaction). The air is gasified and then passes through the heat exchanger>Heat exchange with hot water, low-quality heat and high-temperature heat conducting oil is carried out, so that the temperature of an air recovery heat source is gradually increased (cold water and cold oil are returned to the cold water and cold oil tanks for cooling air during air compression). The flow of the cryogenic pump and the pressure regulating valve is regulated to ensure that the gas in the pipe reaches the pressure and the flow set by us;
Wherein, gas turbine power generation system, waste heat power generation combined cycle system and heat exchangerForming a gas turbine power generation and waste heat power generation circulating system; the high-temperature high-pressure air enters a combustion chamber of the gas turbine, is heated to a set temperature under the condition of burning oil (gas), enters the turbine to expand and do work, converts air energy into mechanical energy, and then drives a generator to convert the mechanical energy into electric energy.
In the waste heat power generation combined cycle system, because the temperature of the exhaust gas of the gas turbine is higher, a non-energy-supplementing waste heat boiler, a steam turbine and a generator are additionally arranged at an exhaust outlet and are combined with the gas turbine for cycle, so that the energy conversion efficiency is improved. From the slaveThe flue gas discharged from the waste heat boiler is reintroduced into the heat exchangerHeat exchange with high-pressure air is carried out, and finally the air is discharged at normal temperature. Thereby achieving the effects of recovering energy to the maximum extent and improving the energy conversion efficiency.
The invention provides a liquid air energy storage power generation system which consists of an air compressor unit, three relatively independent cold and heat exchange energy circulation systems, a high-pressure air expansion liquefying system, a liquid air gasification heating and boosting system and a gas turbine power generation and waste heat power generation circulation system. The core of the technology is as follows:
The temperature of the inlet gas of the compressor is reduced as much as possible, so that the compression efficiency is improved; the pressure of the compressed air is reasonably increased so as to increase the air liquefaction saturation temperature and the liquefaction efficiency;
pumping liquid air into the air gasification heat exchange device through a low-temperature pump, and then performing cold-heat exchange according to process requirements through an independent cold-heat exchange energy circulation system, so that the temperature of gasified air is increased, the enthalpy of the air is increased, and the conversion efficiency of air energy storage is improved;
the high-pressure air heated by energy recovery enters a gas turbine to perform heating expansion work, flue gas enters a non-energy supplementing waste heat boiler, and high-temperature steam generated by the boiler enters the steam turbine to perform expansion work, so that combined cycle is realized;
flue gas discharged from the waste heat boiler is returned to the heat exchangerHeat exchange is carried out with the high-pressure acting gas, so that the temperature of the high-pressure acting gas is increased, the conversion efficiency of air energy storage is improved, and finally, the flue gas is discharged at normal temperature.
As a further improvement of the above embodiment, in one embodiment, the first heat exchange unit includes a first heat exchanger, a second heat exchanger, and a third heat exchanger, air at an outlet of the first low pressure ratio compressor enters the first heat exchanger through a heat medium inlet of the first heat exchanger, a heat medium outlet of the first heat exchanger is connected with the hot water tank, a refrigerant inlet of the first heat exchanger is connected with the cold water tank, a refrigerant outlet of the first heat exchanger is connected with the second low pressure compressor, air at an outlet of the second low pressure compressor enters the second heat exchanger through a heat medium inlet of the second heat exchanger, and a heat medium outlet of the second heat exchanger is connected with the hot oil tank through the third heat exchanger. The third heat exchanger is connected with the expansion machine, and high-pressure air is expanded by the expansion machine to do work, and then the high-pressure air is decompressed to form low-temperature gas which enters the liquefaction tank (6).
In some embodiments, the air compression liquefaction module 101 further includes a high-temperature and high-pressure air cooling unit and a cold-heat exchange energy circulation unit, where the high-temperature and high-pressure air cooling unit is connected to the cold-heat exchange energy circulation unit, and the cold-heat exchange energy circulation unit is connected to the air liquefaction storage unit.
As a further improvement of the above embodiments, in some embodiments, the generator module further includes a turbine, the high-temperature and high-pressure air enters a combustion chamber of the gas turbine, and under the condition of burning oil, the high-temperature and high-pressure air is heated to a preset temperature value, enters the turbine to expand and do work, converts air energy into mechanical energy, and drives the generator to convert the mechanical energy into electric energy.
In view of the greatly improved conversion efficiency, a gas turbine is used in combination with energy storage. The high-pressure air is heated up further after absorbing low-quality heat to the maximum extent and recovering heat storage; the high-pressure air heated by the combustion chamber enters the turbine to expand and do work to generate electric energy.
The invention has the following technical characteristics in the air compression process:
in the air compression process, two-stage low-pressure ratio compression and one-stage high-pressure ratio compression are adopted in order to improve the compression efficiency (more stages of compression are adopted, the efficiency is higher, and the cost is higher). And the low-temperature gas discharged from the liquefaction tank is directly returned to the air inlet of the first-stage press, so that the temperature of the inlet gas of the press is reduced, and the compression energy consumption is reduced.
The outlet gas of the first-stage low-compression ratio press and the second-stage low-compression ratio press are cooled by cold water through heat exchangers (1) and (2) so as to reduce the temperature of the inlet gas of the second-stage press and the third-stage press, thereby reducing the compression energy consumption and achieving the purpose of improving the compression efficiency.
The third-stage high-pressure ratio press compresses air to a high-temperature and high-pressure state, and performs heat exchange with the heat conduction oil through the heat exchanger (3) to heat the heat conduction oil to the high-temperature state, wherein the high temperature can reach about 300 ℃. Meanwhile, the saturation temperature of air liquefaction is increased by increasing the pressure of air, so that the air liquefaction efficiency is improved.
The invention has the following technical characteristics in the air liquefaction process:
the high-temperature high-pressure air cooled by the heat exchanger (3) and the antifreeze cold storage low-temperature liquid flow in opposite directions, and heat exchange is carried out by the heat exchangers (4) and (5). The gas inlet of the expander is selected between the heat exchangers (4) and (5), and the temperature of the gas at the inlet of the expander is controlled by the design of the exchange power of the heat exchangers (4) and (5), so that the requirements that the expansion working efficiency of the expander is highest and the outlet temperature (entering the air liquefying tank) after the air expansion is lower than the air liquefying saturation temperature are met. The air is cooled by the heat exchanger (5) to form low-temperature high-pressure gas, and the low-temperature high-pressure gas enters the air liquefying tank for further cooling and liquefying. The low-temperature gas of the liquid-air separated gas is returned to the inlet of the air compressor 1 for cyclic compression. Three purposes are achieved by this design: the energy is recovered to the maximum extent by the work of the expander; the high-pressure air is reduced to below zero by the low-temperature antifreeze, so that the liquefying efficiency of the air is improved, and heat is stored (the highest boiling point temperature of the antifreeze can reach 120 ℃); the expanded low temperature gas directly enters the gas inlet of the first-stage press, thereby reducing the temperature of the inlet of the press and improving the efficiency of the press (see figure 2 for details).
The invention has the following technical characteristics in the air gasification process:
during air gasification, liquid air is pumped out into the heat exchanger by the cryopumpWith high temperature antifreeze solutionHeat exchange is performed to gasify the liquid air. And the air pressure is regulated to a preset value through a pressure regulating valve to form low-temperature high-pressure air. The antifreeze is cooled to the designed temperature below zero in the air gasification process and returns to the antifreeze low-temperature pool, thus realizing cold recovery.
The low-temperature high-pressure air respectively passes through the heat exchangersAnd sequentially carrying out heat exchange with hot water, low-quality heat and high-temperature heat conduction oil to gradually heat an air recovery heat source to form high-temperature and high-pressure air. And simultaneously, the temperature of the heat storage medium is reduced and returned to the cold tank for cooling the compressed air and storing heat when the air is compressed. Therefore, closed-loop operation of energy recycling is formed, and the conversion efficiency of liquid air energy storage is improved.
In order to improve the efficiency of air power generation, the invention combines the compressed air energy storage with the gas turbine, and has the following technical characteristics:
in order to improve the energy conversion efficiency of the gas turbine, the compressor part of the gas turbine is removed, the liquid air is utilized for gasification expansion to replace the compressor, and a cryopump and a pressure regulating valve are utilized to control the pressure and flow of air entering the gas turbine. The limitation of the optimal pressure ratio of the compressor of the traditional gas turbine is broken through, and the higher air pressure is obtained through the gasification and expansion of liquid air.
According to the invention, when the gas turbine is designed, the bearing capacity of the combustion chamber and the turbine is mainly considered, the bearing capacity of the gas turbine is improved, and the influence of the limit pressure ratio of the gas compressor is successfully avoided, so that the energy conversion efficiency of the gas turbine is effectively improved.
According to the invention, after combined circulation, low-temperature high-pressure air (working gas) formed after liquid air expansion is utilized to recover low quality (flue gas) discharged by the waste heat boiler, so that the energy conversion efficiency is improved.
FIG. 3 is a schematic view of a cycle process of a gas turbine according to an embodiment of the present invention, as shown in FIG. 3, wherein 1-2 in FIG. 3 is the air compression power consumption process of air in a compressor; 2-3, the combustion temperature rising process of the air in the combustion chamber is completed; 3-4, the expansion work process of the air is completed in a turbine; 4-2 is that air is discharged out of the gas engine to enter the atmosphere to finish the heat release process of the cold source, and the thermodynamic cycle of the gas engine is an open type white support cycle.
Relationship between gas turbine efficiency and gas temperature and compressor pressure ratio:
π η ＝max＞π
the efficiency of a simple cycle theoretically increases with increasing pressure ratio. But the actual simple cycle is different. There is a different value of pressure ratio for both maximum specific work and maximum efficiency. The regenerative cycle may bring the two pressure ratio values closer together. Referring to FIG. 4, FIG. 4 is a schematic diagram of the gas temperature and the circulation efficiency according to an embodiment of the invention, the gas temperature T 3 The higher the cycle efficiency.
Corresponds to a gas temperature T 3 There is an optimum pressure ratio at which the corresponding combustion engine efficiency is maximum. The higher the gas temperature, the higher the corresponding optimum pressure ratio, which is the most critical point in the design of a gas turbine. At present, the most advanced gas turbine has a gas temperature of 1300-1400 ℃ and a compressor pressure ratio of 15-20. Thus, gas turbine efficiency is increased and gas turbine performance is improved, primarily from the gas temperature of the gas turbine and the pressure ratio of the compressor.
Influence of the temperature ratio:
T 3 every 100 ℃ is increased, the specific work W is increased by 20% -40%; the efficiency mu is increased by 2% -5%;
effect of actual atmospheric temperature:
lowering T 1 Ratio increase T 3 The impact on gas turbine performance is several times greater.
In order to design a high-efficiency system, the work efficiency and influence factors of all parts of the power generation of the gas turbine are analyzed firstly:
FIG. 5 is a schematic view of a prior art gas turbine engine configuration provided in accordance with an embodiment of the present invention.
And (3) efficiency analysis of the gas compressor:
the parameters of the gas turbine are assumed as follows:
unit shaft power W 0 The method comprises the steps of carrying out a first treatment on the surface of the The pressure ratio is pi; thermal insulation efficiency v of compressor c =0.85; mechanical efficiency mu cm =0.99; ambient temperature T 0 =288; ambient atmospheric pressure P 0 The method comprises the steps of carrying out a first treatment on the surface of the Compressor outlet temperature T 2 The method comprises the steps of carrying out a first treatment on the surface of the Compressor outlet pressure P 2 The method comprises the steps of carrying out a first treatment on the surface of the Air insulation index λ=1.4 during compression of air in the compressor; c (C) P ＝1005J/(kg·K)；
Pressure loss:
combustion chamber Δp b =2% compressor outlet pressure; air side ΔP of heat exchanger ha =3% compressor outlet pressure; air side ΔP of heat exchanger hg =0.04 bar; combustion efficiency v b =0.98; turbine inlet temperature T3 (1100-1400 ℃); the efficiency of the heat exchanger is 0.80; turbine inlet pressure P 3 The method comprises the steps of carrying out a first treatment on the surface of the Turbine adiabatic efficiency μ t =0.87; during expansion of the gas in the turbine, k=1.33, cp' =1156j/(kg·k); low value heat value H of fuel u 。
Compressor outlet air flow parameter P 2 And T 2 Specific work W c Is calculated by (1):
inlet channel outlet parameters:
P 1 ＝σ*P 0 (σ≥0.99)
T 1 ＝T 0
P 2 ＝πP 1
the temperature rise generated by the power consumption of the air compressor is as follows:
the turbine work required for driving the compressor per unit mass flow is:
W tc ＝W t -W c
the compressor specific work is equal to the actual enthalpy increase of air passing through the compressor:
P 4 ＝P 1 +ΔP hg
thus, P 3 /P 4 ＝P 3 (P 1 +ΔP hg )
The temperature drop produced by the overall turbine work:
total turbine work per working medium:
Wt＝Cp’(T 3 -T 4 )kj/kg
the turbine output specific work is:
W c ＝W t -W tc
the temperature rise of the combustion chamber is as follows:
T 3 -T 2
heat exchanger efficiency = 0.80 = (T 3 -T 2 )/(T 4 -T 3 )
T 5 ＝0.8(T 3 -T 4 )+T 2
Fuel/air ratio f:
f＝Cp’(T 5 -T 2 )/H u /v b
the required air flow rate:
Q m ＝W 0 /W t *3600(kg/h)
wherein W is 0 For unit shaft power, W t Is the total turbine work.
It is understood that T 1 Is the inlet temperature of the air compressor, T 2 Is the outlet temperature of the air compressor, T 2 One T 1 Is the temperature rise of the air compressor, T 3 Is the combustion chamber outlet temperature, T 4 Is the turbine outlet temperature, T 3 One T 4 Is turbine temperature drop, T 3 One T 2 Is the temperature rise of the combustion chamber, T 5 Is the outlet temperature of the combustion chamber under the isentropic adiabatic condition, T 5 One T 2 Is the temperature rise of the combustion chamber under the isentropic adiabatic condition.
In practical application, the 10MW gas turbine is taken as a research object, and the three structural modes of the conventional gas turbine, the liquid air energy storage and the pressureless gas turbine are respectively used for modeling. The comparison analysis is performed by simulation calculation, so that an optimal design scheme is obtained.
FIG. 6 is a schematic diagram of fuel consumption rates provided by one embodiment of the present invention, as shown in FIG. 6, for conventional gas turbine power generation, the higher the gas temperature T3, the higher the cycle efficiency. The pressure increase cycle efficiency increases with respect to a gas temperature T3, and the lower the air consumption, the lower the fuel consumption rate. However, for a compressor, there is an optimum pressure ratio, i.e. at this temperature, the combustion engine efficiency is maximum at the optimum pressure ratio. Above the optimal pressure ratio, the pressure ratio is increased, the energy consumption of the press is increased, and the efficiency is reduced.
FIG. 7 is a schematic diagram of the relationship between effective specific work and pressure ratio, as shown in FIG. 7, for a conventional gas turbine generator set front-end charged air energy storage system, gas temperature T, according to one embodiment of the present invention 3 The higher the cycle efficiency. Corresponds to a gas temperature T 3 The method comprises the steps of carrying out a first treatment on the surface of the The inlet pressure of the air compressor is P 1 The higher the compressor pressure ratio, the lower the cycle efficiency. I.e. the higher the pressure ratio of the compressor at this temperature and pressure, the greater the irreversible compression ratio work consumed. If liquid air expansion is used to replace the compressor, the problem of the optimal pressure ratio of the compressor can be avoided, and the pressure entering the combustion chamber of the gas turbine can be greatly increased. Air flow in turbines at equivalent powerThe smaller the amount, the more the fuel consumption rate decreases, which is the gain of the liquid air gasification expansion.
From the simulation calculations and data analysis, it can be seen from FIG. 7 that the effect of the compressor inlet pressure, temperature of a conventional gas turbine on the effective work of the gas turbine. When the press pressure ratio is fixed, the higher the inlet gas pressure is, the lower the effective specific work of the combustion engine is (shown in curves 1-3); when the press ratio is constant, the lower the inlet gas temperature, the higher the specific work of the engine (curves 4 to 7).
It follows that in conventional gas turbine power generation systems, the compressor inlet temperature is relatively sensitive to the irreversible compression ratio work, followed by the compressor inlet pressure, the greater the irreversible compression ratio work, the less the gas turbine effective ratio work. In order to increase the system efficiency, it is contemplated to use liquid air gasification expansion instead of the gas turbine compressor and without limitation by the limiting pressure ratio.
(3) Considering the characteristics of the front-end compressor of the gas turbine, the compressor part is removed, and the air gasification temperature rising module 102 is used for replacing the compressor. Corresponds to a gas temperature T 3 The method comprises the steps of carrying out a first treatment on the surface of the Gas turbine combustor inlet pressure (P 1 ) The higher the cycle efficiency of the gas turbine. Combustor inlet pressure (P) 1 ) Depending on the flow rate and extreme pressure of the liquid air cryopump, the work consumed by the cryopump is much less than that consumed by the compressor. Because the irreversible compression ratio work consumed by the compressor is removed, the effective specific work is greatly increased, and meanwhile, the required air flow is greatly reduced as shown in fig. 8, and fig. 8 is a schematic diagram of the effective specific work and the required air flow corresponding to the air inlet pressure provided by one embodiment of the invention.
(4) The liquid air energy storage system is added with a gas turbine generator (a compressor), and the influence of the gas temperature T3 on the circulation efficiency is large; meanwhile, the pressure P1 of the energy storage air entering the combustion chamber has great influence on the circulation efficiency, and the higher the gas pressure is, the higher the circulation efficiency is. However, in the system design, the pressure-bearing design and the high-temperature-resistant design of the turbine must be considered with great importance, and the excessively high pressure and the excessively high temperature may increase the manufacturing cost of the equipment.
FIG. 9 is a schematic diagram of the relationship between the efficiency of a single engine and the intake pressure according to one embodiment of the present invention.
FIG. 10 is a schematic diagram of air flow versus thermal efficiency of a combustion engine provided in accordance with one embodiment of the present invention.
FIG. 11 is a schematic diagram of fuel consumption versus thermal efficiency of a combustion engine according to one embodiment of the present invention.
As can be seen from fig. 10 and 11, as the pressure entering the combustion chamber of the gas turbine increases, the heat efficiency of the gas turbine increases, and the required air flow decreases and the fuel consumption decreases under the condition of equal power; under equal air pressure conditions, the combustion chamber temperature increases, the thermal efficiency decreases, the required air flow decreases, and the fuel consumption increases.
The temperature of the combustion engine is increased, the conversion efficiency of the single combustion engine is improved, and the thermal efficiency is reduced, which means that the temperature of the flue gas at the outlet of the turbine is increased. Therefore, it is considered that a waste heat boiler and a steam turbine power generation system are added at the back, so that the system efficiency is improved.
Flow design and planning design of key technical points of liquid air energy storage power generation system:
according to simulation calculation and data analysis, energy recycling is grasped, low-quality heat discharged by enterprises with high energy consumption is exchanged by utilizing cold fire of liquid air, and reasonable optimization design is performed by utilizing the characteristic that air compression and expansion are sensitive to gas pressure and temperature, so that a system flow of liquid air energy storage power generation is formed.
The technical key points of the design of the invention are as follows:
1) In the air compression and liquefaction process, the air is compressed in three stages, a heat exchange system is arranged at the air outlet of each stage, the heat exchange system is used for reducing the temperature of air at the inlet of a compressor so as to improve the compression efficiency, heat is stored through cooling media (water and oil), at the moment, the heat storage oil is heated to 280-290 ℃, and the heat storage oil is used for heating air in the gasification expansion process, so that the temperature and the pressure of the gasified liquid air are increased.
2) In order to improve the air liquefying efficiency, the high-temperature and high-pressure air after three-stage compression is cooled to-45 ℃ through a cold storage device (antifreeze), and the antifreeze is heated to 50-60 ℃. Greatly improves the air liquefying efficiency and is liquefied by the liquefying tank.
3) In the power generation, liquid air is pumped by a cryopump (hereinafter, collectively referred to as: stored energy air) is pumped into a heat exchanger to exchange heat with the antifreeze fluid at 50-60 ℃, the stored energy air is gasified and heated to-40 to-50 ℃ and the pressure is more than 3MPa, and the antifreeze fluid is cooled to-50 ℃ for storing cold.
4) The heat exchange is carried out by utilizing the energy storage air (-40 to minus 50 ℃ low temperature high pressure) and the heat (50 to 60 ℃ hot water) stored in the air compression process, and the temperature is further raised to about 120 ℃ by utilizing the low-quality heat (or boiler flue gas) discharged by the low-temperature gas recovery factory.
5) The energy-storage air is further subjected to heat exchange with high-temperature hot oil (280-300 ℃), the temperature of the energy-storage air is further increased to about 280 ℃, and the energy-storage air enters a combustion chamber of a gas turbine to be further increased to more than 1100 ℃ and then enters a turbine for expansion work.
6) The gas turbine designed by the scheme provided by the invention does not have a press part, and the combustion chamber and the turbine part are designed according to specific high temperature and high pressure, so that the energy conversion efficiency is improved to the greatest extent.
7) According to the temperature of the outlet flue gas of the gas turbine, a waste heat boiler can be further arranged, so that the energy conversion efficiency is further improved.
8) The outlet flue gas belt of the waste heat boiler can be used as low-quality heat to exchange heat with energy storage air, so that the temperature of the flue gas is reduced to normal temperature and discharged, the energy is recovered to the maximum extent, and the energy conversion efficiency is improved.
In order to more conveniently and clearly explain the technical characteristics of the invention, by taking the technical index of the PG6561B type gas turbine as a reference and comparing the technical scheme provided by the invention with simulation calculation and data analysis, the obvious advantages of the invention can be seen in the table 3.
It can be seen from table 3 that the combination of liquid air energy storage with a gas turbine can significantly increase the work output of the gas turbine, because the power consumption of the compressed air is converted into the work output of the unit. Meanwhile, the air inlet pressure of the combustion engine is increased, and the system efficiency can be obviously improved. The energy consumption of the system consists of two parts, wherein one part is the heat energy consumed by the combustion of the fuel of the gas turbine, and the other part is the energy consumption of the compressed air. It can be seen from the table that as the pressure of the intake air increases, the air flow required by the gas turbine to perform work decreases, the fuel consumption rate decreases, and the overall efficiency of the system increases.
FIG. 12 is a graph illustrating intake pressure versus energy efficiency ratio according to one embodiment of the present invention. As shown in fig. 12, the air inlet pressure is increased from 1MPa to 4MPa, the energy efficiency ratio is increased rapidly, the increase from 4MPa to 7MPa is obvious, and the increase rate of 7MPa is reduced. From the comprehensive evaluation of energy storage efficiency and gas turbine efficiency, when the air inlet pressure reaches 4MPa, the energy storage conversion efficiency reaches more than 75%, and the combined cycle efficiency of the gas turbine reaches more than 49%.
Table 3: technical parameter comparison of traditional gas turbine and liquid air energy storage power generation
It should be noted that:
energy storage energy efficiency ratio= (gas turbine+cycle work output (KJ/S))/energy storage energy consumption (KJ/S)
Total energy efficiency ratio = (gas turbine+cycle power output (KJ/S))/(combustion energy consumption (KJ/S) +energy storage energy consumption (KJ/S))
If the energy storage conversion efficiency is more than or equal to 75 percent, the following steps are carried out: the energy storage efficiency ratio is more than or equal to 49 percent at least 75 percent, so that the project benefit is good. As can be seen from table 3, when the system air pressure reaches 5MPa, the energy storage conversion efficiency is 75% and the combined cycle efficiency is 49%; the efficiency of power generation of the traditional gas turbine is achieved.
The optimal input pressure is about 7MPa, the pressure rises upwards again, the efficiency is slowly improved, but the design cost of the system is greatly increased. Also, as the inlet pressure increases, the turbine outlet temperature decreases, thus reducing the power generation of the exhaust heat boiler and the turbine in the combined cycle, which is why the total work output decreases.
The temperature of the combustion chamber is increased, the specific work of the gas turbine is increased, the air consumption per unit time is reduced, and therefore the heat efficiency of the energy storage combined cycle is also increased.
The advantage of combined cycle power generation of liquid air energy storage and gas turbine:
1) Compared with gaseous air energy storage, the liquid air energy storage has small storage space and can be stored for a long time at normal temperature and low pressure; the energy storage density is high, safe and reliable, and is not influenced by the resource environment.
2) The liquid air is replaced by low-quality heat (for hot fire) discharged by enterprises with high energy consumption through cold fire in the gasification process, so that the purposes of recovering heat energy and improving energy storage and power generation efficiency are achieved, and the effects of energy conservation and water conservation are achieved.
3) The liquid air energy storage can store heat energy through a cold medium in the air compression process for expanding liquefied air; meanwhile, in the gasification expansion process of liquid air, the cooling medium is utilized to recycle cold energy for the use of compressed air and air liquefaction. The recycling of heat and cold energy will increase the efficiency of air compression and liquefaction.
After the expansion gas comes out, a heat exchanger is added before heat exchange of cold storage (antifreeze) to further cool the high-temperature high-pressure air so as to improve the air liquefying efficiency. The variable frequency motor is adopted by the air compressor, 30% loss in the air liquefaction process can be reduced, and the liquefaction efficiency is improved by 30%.
4) The liquid air energy storage is combined with the power generation of the gas turbine, so that the temperature of the air is effectively improved, and the defect of low efficiency of the traditional gas turbine compressor is avoided. The air inlet pressure can be greatly improved, so that the energy conversion efficiency of the system is improved.
5) The whole system occupies a small area, so that energy can be stored on the power generation side and the user side. And the advantages of light and small weight, low investment and short technical period of the gas turbine device are utilized.
6) The low-quality heat of the factory can be recovered by utilizing the low-temperature advantage of the liquid air energy storage, so that the effect of saving the factory water, electricity and lubricating oil is achieved.
7) The liquid air energy storage is an optimal clean energy conversion device which takes air as an energy storage medium, has strong fuel adaptability and little pollution.
8) The whole system is quick to start, high in automation degree, quick to maintain and reliable in operation. Is a power station scheme with energy storage and peak shaving.
The invention also provides a liquid air energy storage power generation device, comprising: the liquid air energy storage power generation system.
In the development of the liquid air energy storage power generation equipment, firstly, the production process flow design of the system is needed, and after the process flow design is completed, the calculation of process parameters and the model selection stage of the equipment are carried out. For air compression liquefaction plants, process parameters and requirements need to be provided to the manufacturer. Because the purpose of liquefied air is to be used for generating electricity, the purity requirement on air is not high, and only dust is filtered out, dehumidified and dried. Since the liquefied air energy storage power generation needs to be combined with a gas turbine, no air separation is considered.
The exhaust temperature of the exhaust-heat boiler for the combined cycle power generation of the gas turbine is about 160 ℃, so that the exhaust-heat boiler can be introduced into the air gasification process to heat working gas, and the exhaust flue gas temperature is reduced to normal temperature for exhaust.
The following design tasks are as follows:
(1) The design of a process flow of liquid air energy storage power generation, the determination of technical parameters of all components on a production line, equipment model selection and control system design;
(2) A process flow layout design and a factory building foundation design;
(3) A condenser design;
(4) A turbine suitable for air power generation is designed.
The invention uses scene analysis and cost evaluation
1. Energy-saving environment-friendly assessment of the hope of a utilizable scene
The liquid air energy storage is most suitable for being built by depending on high-energy-consumption enterprises, such as thermal power plants, steel plants, chemical plants, glass production plants, paper mills, cigarette factories and the like. The production process flow of the liquid air energy storage power generation can be designed according to the characteristics of the industries so as to achieve the purposes of fully recovering low-quality heat and improving the efficiency of the liquid air energy storage power generation.
(1) The energy storage medium of the liquid air energy storage power generation is air, and the air discharged after the power generation has no influence on the environment. The service life of the equipment is long and can reach 20-30 years, harmful substances are not generated in the treatment after the equipment is scrapped, and the environmental pollution problem is avoided;
(2) The liquid air is replaced by low-quality heat (hot fire) discharged by enterprises with high energy consumption through cold fire in the gasification process, so that the purposes of recovering heat energy and improving energy storage and power generation efficiency are achieved, and the effects of energy conservation and water conservation are achieved;
(3) The liquid air energy storage can be stored for a long time at normal temperature and low pressure, and the energy storage density is high, safe and reliable, and is not influenced by resource environment.
2. Cost analysis and economic evaluation
The production and manufacture of a 10MW and 8-hour (8 ten thousand KWH) liquid air energy storage power generation device are divided into the following parts:
one 50M3/h air compressor and liquefaction production line device comprises 10 50M3 liquid air storage tanks (liquid tanks for short), and the investment is estimated to be about 9,000 ten thousand yuan;
a secondary condenser, investment estimation about 400 ten thousand;
the investment of the turbine for generating electricity by 12MW air is estimated to be about 800 ten thousand yuan;
estimating about 1,000 ten thousand yuan for basic investment of a factory building;
the research and development design cost is about 800 ten thousand yuan;
the cost of 400 ten thousand yuan is not foreseeable.
The total investment of the 10MW, 8-hour (8-kilowatt-hour) liquid air energy storage power generation demonstration project is about 12,000 kiloyuan, and the total investment is 1500 yuan/kwh. Compared with the lead-acid accumulator, the investment cost is basically equal and the service life is three times longer. And the larger the energy storage scale, the lower the investment cost per degree of electricity stored.
If the liquid air energy storage power station enjoys peak-valley electricity price, the electricity price difference is 0.832 yuan/degree, if the conversion efficiency is 75%, the electricity price overflow price is 0.624 yuan/degree, and the daily win is 49,920 yuan; the yearly win is 1,797.12 ten thousand yuan. Six to seven years of recoverable costs are expected.
It is to be understood that the same or similar parts in the above embodiments may be referred to each other, and that in some embodiments, the same or similar parts in other embodiments may be referred to.
It should be noted that in the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "plurality" means at least two.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. A liquid air energy storage power generation system, comprising: the air compression liquefaction module, the air gasification heating module and the generator module are connected in sequence;
the air compression and liquefaction module comprises an air compressor unit, a first heat exchange unit and an air liquefaction storage unit which are connected in sequence, and is used for compressing gaseous air into liquid state and storing energy;
the air gasification heating module comprises a low-temperature pump, a pressure regulating valve, a pressure and flow control unit and a second heat exchange unit which are connected in sequence, and is used for converting liquid air into gas;
the generator module comprises a generator, a gas turbine, a waste heat boiler and a control unit which are sequentially connected, and the generator module is used for generating electric energy.
2. The system of claim 1, wherein the air compressor unit comprises a first low pressure ratio compressor, a second low pressure ratio compressor and a high pressure ratio compressor connected in sequence, wherein air compressed by the first low pressure ratio compressor and the second low pressure ratio compressor enters the high pressure ratio compressor, and the pressure and the temperature of the air are increased by the high pressure ratio compressor.
3. The system of claim 2, wherein the air liquefaction storage unit comprises: the cold water in the cold water tank and the compressed high-temperature air are subjected to heat exchange to be changed into hot water, and the hot water enters the hot water tank to store heat energy.
4. The system of claim 3, wherein the first heat exchange unit comprises a first heat exchanger, a second heat exchanger, and a third heat exchanger, air at an outlet of the first low pressure ratio compressor enters the first heat exchanger through a heat medium inlet of the first heat exchanger, a heat medium outlet of the first heat exchanger is connected to a hot water tank, a refrigerant inlet of the first heat exchanger is connected to a cold water tank, a refrigerant outlet of the first heat exchanger is connected to the second low pressure compressor, air at an outlet of the second low pressure compressor enters the second heat exchanger through a heat medium inlet of the second heat exchanger, and a heat medium outlet of the second heat exchanger is connected to a hot oil tank through the third heat exchanger.
5. The system of claim 4, wherein the third heat exchanger is connected to the expander, and the high-pressure air is expanded by the expander to perform work, and the high-pressure air is decompressed to form a low-temperature gas to enter the liquefaction tank.
6. The system of claim 1, wherein the air compression liquefaction module further comprises a high temperature high pressure air cooling unit and a heat exchange energy circulation unit, the high temperature high pressure air cooling unit being connected to the heat exchange energy circulation unit, the heat exchange energy circulation unit being connected to the air liquefaction storage unit.
7. The system of claim 1, wherein the second heat exchange unit comprises four heat exchangers a, b, c, and d connected in sequence.
8. The system according to claim 7, wherein the second heat exchange unit further comprises a low-temperature antifreeze liquid tank and a high-temperature antifreeze liquid tank, and the liquid air is pumped into the heat exchanger a through a low-temperature pump to exchange heat with the high-temperature antifreeze liquid in the high-temperature antifreeze liquid tank, so that the liquid air is quickly gasified and heated, and the high-temperature antifreeze liquid flows into the low-temperature antifreeze liquid tank after the temperature of the high-temperature antifreeze liquid is reduced to a preset temperature.
9. The system of claim 1, wherein the generator module further comprises a turbine, the high-temperature and high-pressure air enters a combustion chamber of the gas turbine, the high-temperature and high-pressure air is heated to a preset temperature value under the condition of burning oil, and the high-temperature and high-pressure air enters the turbine to expand and do work, so that the air energy is converted into mechanical energy, and then the generator is driven to convert the mechanical energy into electric energy.
10. A liquid air energy storage power generation apparatus, comprising: a liquid air energy storage power generation system as described in any one of claims 1-9.
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