EP3724458A1

EP3724458A1 - Method for storing and producing energy by means of compressed air with additional energy recovery

Info

Publication number: EP3724458A1
Application number: EP18799555.0A
Authority: EP
Inventors: Patrick Briot; David Teixeira
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2017-12-11
Filing date: 2018-11-14
Publication date: 2020-10-21
Also published as: FR3074846A1; FR3074846B1; US20210172372A1; CN111448368A; WO2019115120A1

Abstract

The invention relates to a method for storing and producing energy by means of compressed air, comprising the following steps: - compressing the air using staged compressors, during which time the air is cooled, after at least one compression step, by means of an exchange with a heat transfer fluid, - storing the compressed air and the hot heat transfer fluid after the exchange performed during the compression steps, - expanding the air in multiple stages by means of energy production turbines, during which time the air is heated, after at least one expansion step, by means of the hot transfer fluid tapped from the storage means. According to the invention, after the expanded air is heated and before being recirculated to the compression step, the transfer fluid is cooled by an additional energy recovery loop comprising a pump, an exchanger and a turbine, and an additional transfer fluid.

Description

METHOD FOR STORING AND GENERATING COMPRESSED AIR ENERGY WITH ADDITIONAL ENERGY RECOVERY

The present invention relates to the field of storage and energy production by compression and expansion of air.

The production of electricity from renewable energies, sun through solar panels, wind via onshore wind turbines or at sea, is booming. The main disadvantages of these means of production are the intermittency of the production and the possible non-adequacy between the period of production and the period of consumption. There is therefore a need for a means of storing electricity during production and returning it during a period of need or overconsumption. There are many technologies for this balance, the best known of which is the Pumped Water Transfer Station (STEP) which consists of the use of two water tanks at different altitudes. Water is pumped from the lower basin during the charging phase. The water is turbinated towards the lower basin during the discharge. Other technologies may be the use of batteries of different types (lithium, nickel, sodium-sulfur, lead-acid ...). Flywheel Energy Storage (FES) operates by accelerating a rotor (flywheel) at a very high speed and maintaining energy in the system in kinetic energy. When the energy is extracted from the system, the rotation speed of the steering wheel is reduced as a consequence of the principle of energy conservation. The addition of energy to the system consequently leads to an increase in the speed of the steering wheel.

Most FES systems use electricity to accelerate and decelerate the steering wheel, but devices that directly use mechanical energy are being developed.

Energy storage technology using compressed air is promising. Electricity produced and not consumed is used to compress air at pressures between 40 bar and 200 bar using multi-stage compressors. To minimize the electricity consumption of each compressor, the heat resulting from the compression is eliminated between each stage. The compressed air is then stored under pressure, either in natural cavities (caves) or in artificial reservoirs.

During the power generation phase, the stored air is then sent to turbines to produce electricity. When relaxing, the air cools. In order to avoid too low temperatures (-50 ° C) causing damage in the turbines, the air must be reheated before relaxation. Such facilities have been operating for a number of years now. Among the most famous, we must mention a unit in Germany Huntorf operating since 1978 and in the USA Macintosh (Alabama) operating since 1991. These two facilities have the particularity of using compressed air stored to supply gas turbines. These gas turbines burn natural gas in the presence of pressurized air to generate very hot combustion gases (550 ° C and 825 ° C for the Huntorf unit) and high pressure (40 bar and 11 L). bar) before relaxing them in turbines generating electricity. This type of process emits carbon dioxide. The Huntorf unit could emit approximately 830 kg of C0 ₂ per megawatt of electricity produced.

There is a variant under development. It is a so-called adiabatic process in which the heat resulting from the compression of the air is recovered, stored and returned to the air before relaxing it during energy recovery.

The cooling of the air during compression can be done using exchangers without direct contact between the fluids, only the heat will be transferred from the hot air to the cold fluid. This fluid can be a liquid (water, organic liquid, mineral liquid) or a gas. This fluid then becomes hot and it is stored or not to warm the cold air before the relaxation

The patent application US 2013/0042601 describes a cooling of the air between the compression stages by water through exchangers without direct contact. The hot water is then cooled. The heat needed during the The expansion is provided by hydrocarbon combustion in high-pressure and low-pressure burners. A similar description is made in US 2014 / 0026584A1 and US 2016/0053682A1.

The direct contactless exchangers may be plate heat exchangers (welded or not), tube-calender exchangers, or any device known to those skilled in the art in which there is heat exchange without transfer of material.

The document WO 2016/012764 A1 describes such an indirect exchange between the hot air resulting from the compression and a molten salt by means of exchangers, the air before expansion is reheated using the previously obtained hot molten salt. Such a system is also used in DE 10 2010 055 750 A1 where the fluid for transferring heat from compression to expansion is a saline solution through exchangers.

The cooling of the air can also be done using so-called direct contact exchangers, that is to say that the hot air is sent to a column in which a cold liquid is sent against the current air. The heat of the air will be transferred to the cold fluid that will heat up on contact. In addition to heat, material transfers can occur during contact. These columns, generally, contain elements for improving the contact between the gas phase (air) and the liquid phase (cold fluid) to facilitate the gas-liquid transfer. These elements can be packing, structured or bulk distribution trays equipped with fireplaces. There are also direct contact systems based on solids. Document US 2016/0326958 A1 discloses a system where heat transfer is by direct contact with phase change materials. US2011 / 0016864A1 uses a heat transfer technology with direct contact with molten salts.

To minimize the cost of equipment, the same equipment is used for cooling the hot air resulting from compression and heating the air after expansion because the process operates cyclically. This fact is described in DE 10 2010 055 750 A1 for direct contactless technology and in US patent applications 201 1 / 0016864A1 and US 2016 / 0326958A1 for direct contact heat exchange technology.

There is an imbalance of heat produced by the compression and the heat used by the heating of the air during the relaxation. In the case of using a fluid to transfer heat from the compression to the expansion, this fluid remains hot with temperatures above the acceptable initial temperature for cooling. This will require cooling before it can be recycled for use again.

The object of the present invention is to improve the performance of the storage and power generation unit by using a part of the heat of the heat transfer fluid, whatever the nature of the heat transfer fluid (water , mineral oil, ...), to produce additional electricity and reduce the amount of cold necessary to cool said thermal fluid before recycling.

Thus, the present invention relates to a process for storing and producing energy by compressed air comprising the following steps:

a compression of the air by staged compressors during which the cooling of the air is carried out after at least one compression stage by means of an exchange with a heat transfer fluid,

storage of the compressed air and of said hot heat transfer fluid after exchange during compression,

staged detents of the air by power generation turbines, during which the heating of the air is carried out after at least one expansion stage by said hot transfer fluid withdrawn from said storage,

According to the invention, after heating the air in expansion and before being recycled to the compression stage, said transfer fluid is cooled by a additional energy recovery loop comprising a pump, an exchanger and a turbine and an additional transfer fluid.

The transfer fluid with air may be selected from water, mineral oils, ammonia solutions.

The additional transfer fluid may be chosen from hydrocarbons, such as butane and propane, and ammonia solutions.

Heat exchange equipment may be common to the compression and expansion steps of the compressed air.

Heat exchange equipment can be technology exchanges without direct contact between fluids.

Heat exchange equipment can be technology exchanges with direct contact between fluids.

At least one separator may be disposed on the compressed or expanded air line so as to control a mass transfer between said heat transfer fluid and the air.

Direct contact heat exchange equipment may include packed columns, or tray columns.

In one aspect, said heat transfer fluid is stored in intermediate storage means, before exchanging heat with said additional transfer fluid.

In addition, the invention relates to a compressed air energy storage and production system comprising:

a) Staged compressors, and at least one heat exchanger with a heat transfer fluid is arranged between a compression stage, b) A compressed air storage means and a storage means of said hot heat transfer fluid after exchange during compression, c) power generation turbines, and at least one heat exchanger (with said heat transfer fluid is arranged between an expansion stage, said system comprises a supplementary energy recovery loop comprising a pump, an exchanger and a turbine and an additional transfer fluid, said additional recovery loop being arranged after reheating the air and before being recycled to the compression step.

According to one embodiment, the transfer fluid with air is chosen from water, mineral oils and ammonia solutions.

According to one embodiment, the additional transfer fluid is chosen from hydrocarbons, such as butane and propane, and ammonia solutions.

Advantageously, the heat exchangers are common to the compression and expansion steps of the compressed air.

According to one aspect, at least one heat exchanger is technology exchanges without direct contact between the fluids.

According to one embodiment, at least one heat exchanger is exchange technology with direct contact between the fluids.

According to one embodiment of the invention, at least one separator is arranged on the compressed or expanded air line, so as to control a mass transfer between said heat transfer fluid and the air.

Advantageously, the direct contact heat exchange equipment comprise packed columns, or tray columns.

Advantageously, said system comprises means for intermediate storage of said heat transfer fluid arranged before said additional recovery loop.

The invention will be better understood and its advantages will appear more clearly on reading the description which follows of the various examples from the prior art compared to implementations of the invention, in no way limiting, and illustrated by the figures below. after annexed, among which: - Figure 1 describes a method of storage and production of compressed air energy according to the prior art wherein the heat transfer fluid is water.

FIG. 2 describes the method according to FIG. 1 in which is integrated a supplementary recovery loop according to the invention.

- Figure 3 describes a compressed air energy storage and production process according to the prior art in which the heat transfer fluid exchange in direct contact with the air.

FIG. 4 describes the method according to FIG. 3 in which is integrated a supplementary recovery loop according to the invention.

The present invention proposes to use, in a CAES-type method or system, a supplementary heat recovery loop on the heat transfer fluid of the heat recovered during the compression of the air and after use of this heat when of relaxation.

The invention is suitable for any CAES system and method in which the heat exchanges between the compression and expansion stages comprise at least one heat exchange with a heat transfer fluid. The system and the method comprise at least one cold storage means for storing the cold transfer fluid before being used in at least one heat exchanger arranged in the compression line (between the compression stages). In addition, the system and method include at least one hot storage means for storing the hot transfer fluid before being used in the flash line (between the flash stages).

The additional recovery loop is arranged at the output of the expansion stages, and before the reinjection of the heat transfer fluid the cold storage means.

This additional recovery device is based on cycles using hydrocarbons, or ammonia solutions, the nature of which can be selected according to the final temperature of the thermal fluid. This loop has two steps: A step in which the hot heat transfer fluid is brought into indirect contact with an additional transfer fluid, such as a hydrocarbon, under temperature and pressure conditions in which the hydrocarbon is liquid. During this contact the hot thermal fluid is cooled to a temperature close to but greater than the incoming liquid hydrocarbon. The additional transfer fluid (eg hydrocarbon) liquid vaporizes during this indirect contact.

- The vapors of the additional transfer fluid (for example hydrocarbon vapors) are sent to a turbine in which they are expanded at a pressure such that the temperature is close to but higher than the temperature of the cooling fluid (air, water, etc.). .). After this expansion, the vapors are sent to an exchange device without direct contact with air (or water) to be condensed. The liquid thus obtained has its pressure restored to the initial value before vaporization by means of a pump.

According to the invention, the use of an additional additional transfer fluid cooling cycle (which may include hydrocarbons, the nature of which is selected according to the temperature of the water) allows the CAES process and system to produce more fuel. electricity and spend less energy for cooling the recycled transfer liquid, for example water or oil. This gain is even greater than the final temperature of the transfer liquid is higher.

According to one embodiment of the invention, the system and the method may comprise at least one intermediate storage means, intended to store the heat transfer fluid after the heat exchanges provided in the line of relaxation (after the stages of heating). relaxation). In this case, the additional recovery loop is intended to recover heat contained in this intermediate storage means. After the heat exchange of the transfer fluid with the additional transfer fluid, the transfer fluid can be returned to the cold storage means.

Thus, for this implementation of the invention, the transfer fluid is subjected to the following loop:

storage in the cold storage means,

at least one heat exchange with the gas in the compression line,

storage in the hot storage means,

at least one heat exchange with the gas in the line of relaxation,

storage in the intermediate storage means,

heat exchange with the additional transfer fluid of the supplementary recovery loop, and

- Transfer in the cold storage means.

According to one embodiment of the invention, the CAES system and method may comprise at least one of the following features:

the transfer fluid with air is chosen from water, mineral oils, ammonia solutions,

at least one direct contact heat exchanger,

at least one non-contact heat exchanger, preferably comprising packed columns, or tray columns,

at least one separator disposed on the compressed or expanded air line, so as to control a transfer of mass between said heat transfer fluid and the air,

- The heat exchangers can be common for the compression line and for the line of relaxation, so as to limit the number of devices in the system.

In the description of the various examples and of the invention, the same equipment was used for compression and expansion of the air. The The characteristics of the compressors and turbines used are presented in the following tables.

Example 1: According to the prior art (Figure 1).

This example may be a description of the process with water as a heat transfer fluid instead of a salt solution as described in DE 10 2010 055 750 A1.

Outside air (stream 1), at a temperature of 20 ° C and a pressure of 1.014 bar containing 4.2 mol% of water, enters a compressor stage K-

101 from where it comes out at a higher pressure and at a higher temperature (stream 2). This stream 2 is then cooled to 50 ° C in a heat exchanger (E-101) without direct contact (stream 3) with water at 40 ° C (stream 29). The water leaves the exchanger at a higher temperature (flow 30) to reach a storage tank (T-402). The cooled air has its moisture condensed air (stream 23) and is separated from the air (stream 4) in a gas-liquid separator V-101. This condensed water will join a storage tank (T-301). The air then enters a second compression stage (K-102) where it leaves at a higher pressure and temperature (stream 5). It is then cooled in a heat exchanger without direct contact (E-102) with cold water (flow 31). The hot water leaving the exchanger (stream 32) is sent to a storage tank (T-402). The cooled air (stream 6) enters a gas-liquid separator (V-102) separating the condensed moisture (stream 24) from the cold air (stream 7). Condensed moisture is sent to a storage bin (T-301). The cooled air (stream 7) enters a third compression stage (K-103) from which it emerges (stream 8) at a higher pressure and at a higher temperature. It is then cooled in a direct contactless heat exchanger (E-103) with cold water (stream 33). This hot water is then sent to a storage tank (T-402). The cold air, for its part, enters a gas-liquid separator (V-103) where the condensed moisture (stream 25) is separated from the air (stream 10). This condensed moisture is then sent to a storage tank (T-301). The cold air (10) leaving the separator (V-103) then enters a last compression stage (K-104) where it emerges (flow 1 1) at a higher pressure and temperature. It is then cooled in a direct contactless heat exchanger (E-104) with cold water (flow 36). This stream 36 can be cooled, thanks to an exchanger E-105, at a lower temperature than that of the water used for cooling the stages of the compressor. The hot water (stream 37) leaving the exchanger (E-104) is then sent to a storage tank (T-402). The cold air (stream 12) enters a gas-liquid separator V-104 where the condensed moisture (stream 26) is sent to a storage tank (T-301). The cold air (flow 13), 50 000 kg / h, exiting at a pressure of 136.15 bar and a temperature of 30 ° C is sent to a storage tank (T-201) which can be natural or artificial. It contains only 300 ppm of water. The power consumption for the compression stage is equal to 10.9 MW. The condensed water represents a quantity of 1.35 ton / hour.

During power generation, the stored air (stream 14) is sent from the tank (T-201) to a direct contactless heat exchanger (E-104) with hot water (stream 39) from the storage bin (T-402). The exchanger E-104 is the same as that used for cooling during compression. This saving of equipment is possible because, the process being cyclic exchangers are either used during compression or during relaxation. The schematic diagram describes all the circulations of the fluids, but not the details of all the pipes necessary for the alternate use of the exchangers.

The hot air (stream 15) enters an EX-201 turbine where it undergoes a relaxation. The cooled water (stream 40), leaving the exchanger E-104, is sent to the exchanger E-103 without direct contact where it will heat the air cooled and cooled (stream 16). This heated air (stream 17) is sent to a second turbine EX-202 where it will be expanded at a lower pressure and pressure (stream 18). The cooled water (stream 41) leaving the exchanger E-103 is sent to the exchanger without direct contact E-102 where it will heat the air exiting the turbine EX-202 which will then be reheated (stream 19). . This hot air will then be sent to a third EX-203 turbine to be expanded to a lower pressure (stream 20). The less hot water (stream 42) leaving the exchanger E-102 will be sent to another exchanger without direct contact E-101. This exchanger will be used to heat the outgoing air (flow 20) of the turbine EX-203 before entering (flow 21) in the last turbine EX-204. The air after final expansion is released into the atmosphere (stream 22) at a pressure of 1.02 bar and a temperature of 10 ° C.

The hot water that has been used for the various pre-expansion air heats (stream 43) will be at a final temperature of 126 ° C. Before being recycled, this water will need to be cooled either by a water exchanger or with an air cooler. The cooling power required is 5.5 MWthermic.

The electric power produced by the successive detents is equal to 5.2 MW.

Example 2: According to the invention (Figure 2).

The method of storage and production of energy by compressed air is identical to that described in Example 1.

In the same way, the air after final expansion is released into the atmosphere (stream 22) at a pressure of 1.02 bar and a temperature of 10 ° C. The hot water, heat transfer fluid that has been used for the various pre-expansion air heats (stream 43) is at a final temperature of 126 ° C.

According to the invention, this hot water is then sent to an additional non-contact direct heat transfer device E-501 where it will be cooled (stream 44) at a temperature of 50 ° C. by heat exchange with a liquid butane stream ( flow 46). This liquid butane stream, at a pressure of 21 bar and a temperature of 41.4 ° C., is vaporized during the heat exchange and is then at a pressure of 20.5 bar and a temperature of 1 16 ° C. C. The cooled water (stream 44) is then sent to an exchanger (E-401) where it will be cooled by water or air at a temperature of 40 ° C (stream 45).

Steam butane (stream 47) is sent into a turbine (EX-501) to be expanded at a pressure of 4 bar. The flux (stream 48) is then sent to a heat transfer device (E-502) to be condensed at 40 ° C and a pressure of 3.88 bar. The pump (P-501) will reduce the flow of liquid butane (stream 49) to a pressure of 21 bar and a temperature of 41.4 ° C to be recycled to the additional non-contact heat transfer device E-501.

The required cooling power of the equipment E-401 and E-502 is equal to 4.9 MW thermal compared to 5.5 MWthermic of the previous example.

The expansion of the butane, reduced by the power consumption of the P-501 pump, will produce 0.55 MW to add to 5.2 MW of the air cycle, a total of 5.75 MW.

Thus, the addition of an additional energy recovery loop on the expanded heat transfer heat transfer fluid in the turbine stages increases the overall efficiency of the process.

The additional recovery fluid may be a hydrocarbon, for example butane, propane, and also be in the form of ammonia or ammonia solution. More generally, the invention also includes a method in which only one or more stages of compression (s) and expansion (s) are (are) concerned.

Example 3: According to the prior art (Figure 3).

Outside air (stream 1), at a temperature of 20 ° C and a pressure of 1.014 bar containing 4.2 mol% of water, enters a compressor stage K-101 where it leaves at a higher pressure and at a higher temperature (stream 2). This stream 2 is then cooled to 50 ° C. in a direct contact heat exchanger (C-101) with water at 40 ° C. (stream 21). This exchanger C-101 consists of a packed column where the hot air (flow 2) enters through the bottom of the column. The cold water (stream 21) is injected at the top of the column, the flows are cross-flow: one flows up (the air) and the other goes down (the water). The hot water exits the column at a lower temperature (flow 22) to reach a storage tank (T-402). The cooled air exits the column from above (stream 3) and then enters a second compression stage (K-102) from where it exits at a higher pressure and temperature (stream 4). It is then cooled in a direct contact heat exchanger (C-102) with cold water (stream 25). The hot water leaving the column downwards (stream 26) is sent to a storage tank (T-403). The cooled air (stream 5) enters a third compression stage (K-103) from which it emerges (stream 6) at a higher pressure and at a higher temperature. It is then cooled in a direct contact heat exchanger (C-103) with cold water (stream 29). This hot water (stream 30) is then sent to a storage tank (T-404). The cold air (stream 7) exits through the top of the column and then enters a last compression stage (K-104) where it emerges (stream 8) at a higher pressure and temperature. It is then cooled in a direct-contact heat exchanger (C-104) with cold water (stream 34). This stream 34 can be cooled, thanks to an exchanger E-105, at a lower temperature than that of the water used for cooling the stages of the compressor. The hot water (stream 35) leaving the bottom of the column (C-104) is then sent to a storage tank (T-405). The cold air (flow 9), 50 000 kg / h, exiting at a pressure of 134.34 bar and a temperature of 30 ° C is sent to a storage bin (T-201) that can be either natural or artificial. It contains only 320 ppm of water. The power consumption for the compression step is equal to 10.9 MW, which is identical to those of Examples 1 and 2.

During the generation of electricity, the stored air (stream 10) is sent from the tank (T-201) to a direct-contact heat exchanger (C-104) with hot water (stream 36) or from the tank. storage (T-405). The exchanger (C-104) is the same column that was used for cooling during compression. This saving of equipment is possible because, the process being cyclic exchangers are either used during compression or during relaxation. The schematic diagram describes all the circulations of the fluids, but not the details of all the pipes necessary for the alternate use of the exchangers.

The hot air (flow 1 1) leaves the top of the column and enters an EX-201 turbine where it undergoes relaxation. The cooled water (stream 37) leaving the bottom of the column C-104 is sent to a storage tank T-406, also called intermediate storage means. The air exiting the turbine EX-201 is sent (stream 12) to the direct contact heat exchanger C-103 where it will be heated by water flowing against the current from the storage tank T-404 (flow 31). The cooled water (stream 32) is sent to a storage tank (T-406). This heated air (stream 13) is sent to a second turbine EX-202 where it will be expanded at a lower pressure and pressure (stream 14). It is then reheated by water (stream 27) from storage tank T-403. The cooled water (stream 28) leaving the bottom of the column C-102 is sent to a storage tank T-406. The heated air (stream 15) is sent to an EX-203 turbine where it will be expanded to a lower pressure (stream 16). This cold air will be heated by hot water (stream 23) from storage tank T-402 in the C-101 direct contact heat exchanger. This cooled water (stream 24) will be sent to a T-406 storage tank. The heated air (stream 17) will then be sent to a last EX-204 turbine to be expanded to a lower pressure (stream 18). This cold air will then be sent to a V-201 gas-liquid separator to separate the air (stream 19) from the liquid water that may be present (stream 38). This water will be sent to the T-406 storage bin. The air, 50,800 kg / h, after final expansion is released into the atmosphere (stream 19) at a pressure of 1.02 bar and a temperature of 22 ° C. The hot water that has been used for the various pre-expansion air heats (stream 39) will be at a final temperature of 65.7 ° C. Before being recycled, this water will need to be cooled either by a water exchanger or with an air cooler. The required cooling power is 5.3 MWthermic.

The electric power produced by the successive detents is equal to 4.45 MW.

Example 4 According to the invention (Figure 4).

FIG. 4 illustrates, in a nonlimiting manner, an embodiment of the invention.

The method and system for storage and production of energy by compressed air is identical to that described in Example 3.

In the same way, the air, 50,800 kg / h, after final expansion is released into the atmosphere (stream 19) at a pressure of 1.02 bar and a temperature of 22 ° C. The hot water that has been used for the various air heats after detents (stream 39) will be at a final temperature of 65.7 ° C in the tank T-406.

This hot water is then sent into a non-contact direct heat transfer device E-501 where it will be cooled (stream 40) at a temperature of 50 ° C by heat exchange with a stream of liquid propane (stream 44). This liquid propane stream, at a pressure of 19.5 bar and a temperature of 40.8 ° C, is vaporized during the heat exchange and is then at a pressure of 19 bar and a temperature of 55.6 ° C. ° C. The cooled water (stream 40) is then sent to an exchanger (E-401) where it will be cooled by water or air at a temperature of 40 ° C (stream 41).

Steam propane (stream 45) is sent to a turbine (EX-501) to be expanded to a pressure of 14.3 bar. It will then be sent into a heat transfer device E-502 to be condensed at 40 ° C and a pressure of 13.9 bar. The P-501 pump will return the liquid propane to a pressure of 19.5 bar and a temperature of 40.8 ° C.

The required cooling power of the equipment E-401 and E-502 is equal to 5.2 MWthermic compared to 5.3 MWthermic of the previous example.

The expansion of propane, reduced by the power consumption of the P-501 pump, will produce 0.09 MW to add to the 4.45 MW of the air cycle, a total of 4.54 MW.

More generally, the invention also comprises a method and a system in which only one or more stages of compression (s) and expansion (s) are (are) concerned.

The summary table below summarizes the main results of the different examples.

According to the invention, the use of an additional transfer fluid cooling cycle comprising hydrocarbons, the nature of which is selected according to the temperature of the water, allows the CAES process and system to produce more electricity and to spend less energy for cooling the recycled transfer liquid, for example water or oil. This gain is even greater than the final temperature of the transfer liquid is higher.

Claims

A method for storing and producing energy by compressed air comprising the steps of:

a) A compression of the air by step compressors (K-101, K-102, K-103, K-104) during which the cooling of the air is carried out after at least one stage of compression using an exchange with a heat transfer fluid (C-101, C-102, C-103, C-104),

b) Storage of compressed air and of said hot heat transfer fluid after exchange during compression,

(c) Staged air stripping by power generation turbines (EX-201, EX-202, EX-203, EX-204), during which the air is reheated prior to at least one stage expansion by said hot transfer fluid withdrawn from said storage (C-101, C-102, C-103, C-104),

characterized in that, after reheating of the expansion air and before being recycled to the compression stage, said transfer fluid is cooled by a supplementary energy recovery loop comprising a pump (P-501), an exchanger (E-501) and a turbine (EX-501) and an additional transfer fluid.

2) Process according to claim 1, wherein the transfer fluid with air is selected from water, mineral oils, ammonia solutions.

3) Method according to one of the preceding claims, wherein the additional transfer fluid is selected from hydrocarbons, such as butane and propane, and ammonia solutions.

4) Method according to one of the preceding claims, wherein the heat exchange equipment (C-101, C-102, C-103, C-104) are common to the compression and expansion steps of the compressed air . 5) Method according to one of the preceding claims, wherein at least one heat exchange equipment (C-101, C-102, C-103, C-104) is technology exchanges without direct contact between the fluids .

6) Method according to one of the preceding claims, wherein at least one heat exchange equipment (C-101, C-102, C-103, C-104) is technology exchanges with direct contact between the fluids .

7) The method of claim 6, wherein at least one separator (V-101, V-102, V-103, V-104) is disposed on the line of compressed or expanded air, so as to control a transfer of mass between said heat transfer fluid and air.

8) Method according to one of claims 6 or 7, wherein the direct contact heat exchange equipment comprise packed columns, or tray columns.

9) Method according to one of the preceding claims, wherein said heat transfer fluid is stored in intermediate storage means (T-406), before exchanging heat with said additional transfer fluid.

10) Compressed air energy storage and production system comprising:

a) Staged compressors (K-101, K-102, K-103, K-104), and at least one heat exchanger (C-101, C-102, C-103, C-104) with a fluid heat transfer is arranged between a compression stage,

b) means for storing compressed air (T-201) and means for storing said hot heat transfer fluid (T-402, T403, T-404, T-405) after exchange during compression, (c) Power generation turbines (EX-201, EX-202, EX-203, EX-204), and at least one heat exchanger (C-101, C-102, C-103, C-104 ) with said heat transfer fluid is arranged between an expansion stage, characterized in that said system comprises a supplementary energy recovery loop comprising a pump (P-501), an exchanger (E-501) and a turbine ( EX-501) and an additional transfer fluid, said additional recovery loop being arranged after re-heating the air and before being recycled to the compression step.

11) System according to claim 10, wherein the transfer fluid with air is selected from water, mineral oils, ammonia solutions.

12) System according to one of claims 10 or 1 1, wherein the additional transfer fluid is selected from hydrocarbons, such as butane and propane, and ammonia solutions.

13) System according to one of claims 10 to 12, wherein the heat exchangers (C-101, C-102, C-103, C-104) are common to the compression and expansion steps of the compressed air .

14) System according to one of claims 10 to 13, wherein at least one heat exchanger (C-101, C-102, C-103, C-104) is technology exchanges without direct contact between the fluids .

15) System according to one of claims 10 to 14, wherein at least one heat exchanger (C-101, C-102, C-103, C-104) is the exchange technology with direct contact between the fluids .

The system of claim 15, wherein at least one separator (V-101, V-102, V-103, V-104) is disposed on the compressed air line. or expanded, so as to control a mass transfer between said heat transfer fluid and the air.

17) System according to one of claims 15 or 16, wherein the direct contact heat exchange equipment comprise packed columns, or tray columns.

18) System according to one of claims 10 to 17, wherein said system comprises an intermediate storage means (T-406) of said heat transfer fluid arranged before said additional recovery loop.