WO2021023713A1

WO2021023713A1 - System and method for storing and recovering energy by isothermal compression and expansion of air

Info

Publication number: WO2021023713A1
Application number: PCT/EP2020/071811
Authority: WO
Inventors: David Teixeira; Philippe Pagnier
Original assignee: IFP Energies Nouvelles
Priority date: 2019-08-07
Filing date: 2020-08-03
Publication date: 2021-02-11
Also published as: FR3099795A1; FR3099795B1

Abstract

The present invention relates to a system for storing and recovering energy by compressed gas, comprising at least one rotodynamic fluid-compression means (1), at least one compressed-gas storage means (3) and at least one means for rotodynamic expansion of the compressed fluid in order to generate energy. The fluid comprises the gas and a second, preferably liquid, phase. Moreover, the system comprises a means for injecting the second phase upstream or into at least one rotodynamic compression means (1), and/or upstream or into at least one rotodynamic expansion means.

Description

SYSTEM AND METHOD FOR STORAGE AND RECOVERY OF ENERGY BY COMPRESSION AND ISOTHERMAL RELAXATION OF THE AIR

Technical area

The present invention mainly relates to the field of energy storage by compressed air.

The production of electricity from renewable energies, for example through solar panels, or from onshore or offshore wind turbines, is booming. The main disadvantages of these means of production are the intermittence of production and the possible mismatch between the period of production and the period of consumption. It is therefore important to have an energy storage system during production to restore it during a period of consumption.

There are many technologies that allow this balance.

Among them, the best known is the Water Transfer Station by Pumping (STEP) which consists of the use of two water reservoirs at different altitudes. Water is pumped from the lower basin to the upper basin during the charging phase. The water is then sent to a turbine, towards the lower basin, during the discharge.

The use of batteries of different types (lithium, nickel, sodium-sulfur, lead-acid ...) can also meet this need for energy storage.

Another technology, Flywheel Energy Storage (FES), is to accelerate a rotor (flywheel) to a very high speed and hold the energy in the system as kinetic energy. When energy is extracted from this FES system, the rotational speed of the flywheel is reduced as a result of the principle of energy conservation. Adding energy to the FES system therefore results in an increase in flywheel speed.

The technology of energy storage by using a compressed gas (often compressed air) is promising. The energy produced and not consumed is used to compress air to pressures between 40 bar and 200 bar using compressors (which can be multi-stage). During compression, the air temperature rises. In order to limit the cost of the storage tanks and minimize the compressor electricity consumption, the air can be cooled between each compression stage. The compressed air is then stored under pressure, either in natural cavities (caverns) or in artificial reservoirs. There is a variant in development. This 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 expanding it. This is AACAES technology (derived from the English “Advanced Adiabatic Compressed Air Energy Storage”).

In an AACAES system, compressed air is stored in a tank independently for heat storage. In such a system, the air is stored at a temperature close to ambient temperature (a priori less than 50 ^l ). Such a system therefore has a heat reservoir and a pressurized air reservoir. The presence of these two reservoirs significantly impacts the cost of the system.

Prior art

In a prior art compressed air energy storage and recovery system, the heat is either recovered in a heat storage means (AACAES system), or the air is cooled between each compression stage and / or expansion, which requires heat exchange means (for example a heat exchanger) between each compression or expansion stage. These systems therefore require heat exchangers to recover the heat or heat the fluid. The presence of these exchangers has a negative impact on the cost of the system.

Summary of the invention

The system according to the invention consists in performing an isothermal compression or expansion so as to avoid the use of heat exchangers. Thus, the cost of the system is reduced and the system is simpler.

For this, the invention relates to a system for storing and recovering energy by compressed gas comprising at least one means of rotodynamic compression of fluid, at least one means of storage of compressed gas, at least one means of rotodynamic expansion of the fluid. compressed to generate energy. The fluid comprises the gas and a second phase, preferably liquid. In addition, the system comprises means for injecting the second phase upstream or into at least one means of rotodynamic compression, and / or upstream or into at least one means of rotodynamic expansion. The purpose of the second phase is to limit the increase in the temperature of the gas during the compression phase. Thus, the compression and / or the relaxation are carried out isothermally. The invention relates to a system for storing and recovering energy by compressed gas comprising at least one means of rotodynamic compression of fluid, at least one means of storage of compressed gas, at least one means of rotodynamic expansion of said compressed fluid to generate an energy. Said fluid comprises said gas and a second phase and the system comprises means for injecting said second phase upstream or inside at least one rotodynamic compression means, and / or upstream or inside it. 'at least one means of rotodynamic expansion.

According to one implementation of the invention, the system comprises at least one separation means positioned after the rotodynamic compression means or after the rotodynamic expansion means.

Preferably, said second phase is a liquid, preferably water.

Advantageously, the system comprises at least one means for storing said second phase, said means for storing said second phase being connected to at least one injection means or to at least one separation means.

According to one embodiment of the invention, each injection means and / or each separation means is connected to a means for storing said second different liquid phase.

Alternatively, each injection means and / or each separation means are connected to a storage means for said second phase, said storage means for said second phase possibly being common to several injection means and / or separation means.

According to a variant of the invention, all the injection means and / or all the separation means are connected to a single storage means for said second phase.

According to an implementation of the system according to the invention, the system comprises at least one mixing means upstream of at least one compression means and / or a separation means downstream of at least one compression means.

Advantageously, the system comprises at least one mixing means upstream of at least one expansion means and / or a separation means downstream of at least one expansion means.

According to a variant of the invention, at least one mixing means is integrated into at least one rotodynamic compression means or at least one rotodynamic expansion means. The invention also relates to a method for storing and recovering energy by compressed gas comprising the following steps: a1) a gas is compressed by means of rotodynamic compression; b1) said compressed gas is stored; c1) said compressed gas is expanded by means of rotodynamic expansion.

In addition, during or before the compression or expansion steps, a second phase is injected into said gas.

Preferably, said second phase is a liquid, preferably water.

Advantageously, step a1) is repeated successively several times.

Advantageously, step c1) is repeated successively several times.

According to an implementation of the method of the invention, said second phase is mixed with the compressed gas, between the injection of the second phase and the compression or expansion.

According to a variant of the invention, said second phase and said compressed gas are separated after the compression or expansion step.

List of Figures

Other characteristics and advantages of the system and of the method according to the invention will become apparent on reading the following description of non-limiting examples of embodiments, with reference to the appended figures and described below.

Figure 1 shows a first part of a first embodiment of the system according to the invention.

Figure 2 shows a second part of a first embodiment of the system according to the invention.

Figure 3 shows a first part of a second embodiment of the system according to the invention.

FIG. 4 represents a second part of a second embodiment of the system according to the invention. FIG. 5 represents an alternative of a first part of a third embodiment of the system according to the invention.

Figure 6 shows an embodiment of a rotodynamic machine for compression or relaxation for the system or method according to the invention.

Description of embodiments

The invention relates to a system for storing and recovering energy by compressed gas comprising at least one means of rotodynamic compression of fluid, at least one means of storage of compressed gas and at least one means of rotodynamic expansion of the compressed fluid to generate an energy. Thus, the compression means allows the compression of a fluid (the fluid comprising the gas), making it possible to limit the storage space of the compressed gas in the storage means. For energy recovery, the compressed gas leaves the storage means to be expanded in the rotodynamic expansion means. During this relaxation, electricity can for example be generated.

A rotodynamic expansion or compression means comprises an internal rotating part which generates compression / expansion. For example, this internal part may comprise a hub on which blades are fixed, the hub being driven in rotation by a rotation shaft, which may itself be driven in rotation, for example by an electric motor. For a means of rotodynamic compression, the rotation of the shaft drives that of the blades and thus compresses the fluid. Conversely, when the means is a means of rotodynamic expansion, the incoming fluid drives the blades in rotation. It thus releases part of its kinetic and calorific energy, which leads to a loss of pressure. The rotating blades drive a shaft which can itself drive an electric generator to deliver electricity.

The fluid comprises the gas and a second phase, preferably liquid. The second phase serves to limit the increase in temperature of the gas during compression or on the contrary to prevent it from cooling too strongly during expansion. The addition of this second phase therefore allows compression or expansion of the compressed gas in a substantially isothermal manner. As a result, the system does not require any means of heat exchange, such as a tube exchanger, a plate exchanger or even a contactless exchanger.

Furthermore, the system comprises means for injecting (such as an injector) of the second phase upstream or into at least one rotodynamic compression means, and / or upstream or into at least one rotodynamic expansion means. Therefore, the operation isothermal within the means of compression or rotodynamic expansion is improved. In addition, the use of means of compression or rotodynamic expansion makes it possible to improve the homogeneity of the mixture between the gas and the second phase. A volumetric piston machine would not allow good homogeneity of the mixture thus formed. Indeed, the type of positive-displacement compressor used for compressing gas with high flow rates is often a compressor of the screw compressor type, or piston compressor. These generally require lubrication of the friction elements, often incompatible with a gas coolant such as water for example, so that the air must, in most cases, be dried at the inlet of the gas. compressor. Conversely, a specific rotodynamic machine is designed for the compression of a mixture of gas and liquid. In the case of gas storage, the two-phase rotodynamic machine is called a wet compressor. It allows good homogeneity of the fluids.

The invention makes it possible to inject liquid into the very heart of the rotodynamic machine, to control both a rate of gas, a particle size of the drops and the homogeneity of the mixture, and thus to control the temperature of the gas during its compression. , or its relaxation.

Preferably, the system may include at least one separation means positioned after the rotodynamic compression means or after the rotodynamic expansion means. Thus, the second phase is separated from the gas after compression or expansion so as not to degrade the efficiency of the following stages and / or not to be stored with the gas in the storage means.

Preferably, the system can comprise a separation means after each compression stage, comprising a rotodynamic compression means, and after each expansion stage comprising a rotodynamic expansion means.

Advantageously, the second phase can comprise a liquid and preferably this liquid can be water. The use of liquid allows for better temperature control during compression or expansion. The water provides good cooling / temperature maintenance efficiency while ensuring minimal cost.

According to one embodiment of the system according to the invention, the system can comprise at least one storage means of the second phase, this storage means of the second phase being able to be connected to at least one injection means or to at least a means of separation. As a result, it is possible to inject and / or recover the second phase so as to better control the temperature of the second phase when it is injected or withdrawn and thus, better to control the isothermal compression or expansion. According to a variant of the invention, each injection means and / or each separation means can be connected to a different second phase storage means. As a result, the temperature of each tank of the second phase is controlled and thus the isothermal transformations of each compression or expansion stage are better controlled.

According to an alternative of the invention, each injection means and / or each separation means can / can be connected to a storage means of the second phase, this storage means of the second phase possibly being common to several injection means and / or separation means. Thus, it is possible to use the same storage means to inject or recover the second phase at a substantially homogeneous temperature. This alternative makes it possible to limit the number of reservoirs required for the second phase, while ensuring good control of the injection temperatures of the second phase in the various injection or separation means so as to control the isothermal profile of the transformations ( compression, relaxation).

Advantageously, all the injection means and / or all the separation means can be connected to a single storage means for said second phase. This solution has the advantage of reducing the number of tanks for the second phase and therefore the overall cost of the system.

Preferably, the system may comprise at least one mixing means upstream or inside at least one rotodynamic compression means and / or a separation means downstream of at least rotodynamic compression means. The addition of a mixing means upstream or inside the rotodynamic compression means allows the use of a homogeneous fluid in the rotodynamic compression means (for example a multiphase compressor or a multiphase pump) so as to improve isothermal compression. The addition of the separation means downstream of the rotodynamic compression means makes it possible to remove the second phase, so as to keep the storage only of the compressed gas. The addition of the separation means downstream of the rotodynamic compression means makes it possible to remove the second phase, so as to avoid an excessive second phase rate in the following compression stages, in particular when the second phase is liquid. Indeed, a high level of liquid could damage the rotodynamic compression means, in particular when this compression means is not suitable for operating with high levels of liquid. The mixing means makes it possible to guarantee the gas content, the particle size of the drops and the homogeneity of the mixture to ensure a controlled isothermal transformation, while ensuring good compression.

Further, the system may also include at least one mixing means within or upstream of at least one expansion means and / or downstream separation means of at least one expansion means. The addition of a mixing means inside or upstream of the rotodynamic expansion means allows the use of a homogeneous fluid in the rotodynamic expansion means (for example a turbine or a multiphase mixer) so as to improve isothermal relaxation. The addition of the separation means downstream of the rotodynamic expansion means makes it possible to remove the second phase, so as to avoid an excessive second phase rate in the following expansion stages, in particular when the second phase is liquid. Indeed, a high level of liquid could damage the means of rotodynamic expansion, in particular in the case of a turbine. The mixing means makes it possible to guarantee the gas level, the particle size of the drops and the homogeneity of the mixture in order to ensure a controlled isothermal transformation, while ensuring good expansion.

Preferably, a mixing means can in particular be a mixer to improve the homogeneity of the mixture of the second phase with the gas.

According to an advantageous embodiment, at least one mixing means can be integrated with at least one means of rotodynamic compression or at least one means of rotodynamic expansion. Indeed, the use of, for example, a multiphase compressor can perform both compression and mixing of the whole. Indeed, a multiphase compressor is a specific rotodynamic machine whose geometry makes it possible not to separate the liquid phase from the gas phase. The two phases are thus intimately and advantageously mixed as homogeneously as possible. This makes it possible to maximize heat exchanges and to cool the gas more efficiently during its compression. Thus, the system is simplified. For the rotodynamic expansion means, the multiphase turbine can be used in reverse mode, that is to say with a flow of fluid in the opposite direction to the flow of fluid in compression mode. The fluid then undergoes an expansion during the transfer of its energy to the rotating shaft in the form of mechanical energy. The liquid injected into the expansion element makes it possible to heat the gas.

The invention also relates to a method for storing and recovering energy by compressed gas comprising the following steps: a1) a gas is compressed; b1) the compressed gas is stored; c1) the compressed gas is expanded.

In addition, during or before the compression or expansion steps, a second phase is injected into the gas. The addition of the second phase allows for isothermal compression or expansion and therefore avoids the use of heat exchangers.

Advantageously, the second phase can be a liquid, preferably water. Thus, the temperature profile of the fluid during compression or expansion is better controlled.

According to one variant, step a1) can be repeated successively several times. Thus, rotodynamic compression means can be used with optimum efficiency for each range of pressure variation. This variant also has the advantage of allowing the use of multiphase rotodynamic compression means, and of improving the performance of the system.

Preferably, step c1) can be repeated successively several times. Thus, rotodynamic expansion means can be used with optimum efficiency for each range of pressure variation. This solution also has the advantage of allowing the use of multiphase rotodynamic expansion means and of improving the performance of the system.

According to an implementation of the method according to the invention, the second phase can be mixed with the compressed gas, between the injection of the second phase and the compression or expansion. As a result, the fluid enters the compression means in a homogeneous manner, which allows good control of the temperature development in the compression means.

According to a variant of the process according to the invention, the second phase and the compressed gas can be separated after the compression or expansion step. Thus, the rate of second phase in the fluid remains low even if there are several stages of compression or expansion. This is particularly advantageous when the second phase is liquid. Indeed, a high level of liquid could damage the means of compression or rotodynamic expansion. In addition, it would be more difficult to control the temperature of the fluid.

[Fig 1] schematically and non-limitingly illustrates part of an energy storage and recovery system according to one embodiment of the invention. This part concerns the phase of energy storage by compressed air. This part of the system comprises two second phase tanks 33 and 35, a mixing means such as a mixer 41, a separation means 53 such as a separator, a rotodynamic compression means 1 such as a two-phase rotodynamic compressor and a compressed air storage means 30. Gas, preferably air taken from the ambient medium is mixed within the mixer 41 with the second phase, for example water, coming from the reservoir 35. The fluid thus obtained after the mixture of the second phase with the gas then passes through the compressor 1, in which it is compressed. The two-phase rotodynamic compressor 1 allows the compression of the liquid and the gas simultaneously and improves the mixing between the two phases, thanks to the rotation of the flows that it induces. The good homogeneity of the mixture thus allows a homogeneity of the temperatures, the second phase can then correctly cool the gas during compression. The compression is then almost isothermal, which makes it possible to avoid any heat exchanger at the outlet to cool the gas. The reservoirs 33 and 35 can be distinct or can form a single entity.

[Fig 2] schematically and non-limitingly illustrates a second part of an energy storage and recovery system according to one embodiment of the invention. This part concerns the phase of energy recovery by compressed air. This second part can be combined with the first part of FIG. 1 to form a system for storing and recovering energy by compressed gas. This part of the system comprises two second phase tanks 33B and 35B, a mixing means such as a mixer 47, a separation means 55 such as a separator, a two-phase rotodynamic expansion means 2 such as a rotodynamic turbine and a compressed air storage means 30. Compressed gas stored in the reservoir 30 is sent to the two-phase turbine in order to recover the energy contained in the gas. The energy can, for example, then be transformed into electricity via a generator driven by the turbine. Before entering the rotodynamic expansion means 2, the compressed gas issuing from the reservoir 30 is mixed in the mixing means 47, such as a mixer, with a second phase issuing from the reservoir 33B. This second phase, preferably liquid, makes it possible to achieve an almost isothermal expansion within the rotodynamic expansion means 2. When the fluid leaves the turbine, the gas and the second phase are separated in a separation means 55, such that a separator. The second phase emerging from the separation means 55 is then stored in the tank 35B. The reservoirs 33B and 35B can be distinct or can form a single entity. According to another variant, the reservoirs 33B and / or 35B can also be common with the reservoirs 33 and 35 of [Fig 1].

[Fig 3] shows schematically and without limitation another variant of a first part concerning the energy storage of the system. The references identical to those in [Fig 1] correspond to the same elements and will therefore not be re-detailed. Unlike [Fig 1] where a single compression stage was produced via the rotodynamic compression means 1, [Fig 3] has three rotodynamic compression stages 11, 12 and 13. This staging allows more efficient outputs by a lower pressure variation across each rotodynamic compression means 11, 12, and 13. In addition, this feature allows the use of standard rotodynamic compression means, which allows a reduction in system cost, no adaptation or design not being necessary.

Just upstream of each compression stage, a second phase is mixed with the gas and just downstream of each compression stage, the second phase is separated from the compressed gas. Thus, temperature control can be optimal in each compression stage, so as to achieve a quasi-isothermal transformation. Thus, the gas is first mixed with the second phase coming from the reservoir 35, in the mixer 41. The fluid thus formed is compressed in the rotodynamic compressor 11, which makes it possible to maintain, or even improve, the mixture. Thus, the compression is quasi-isothermal. The compressed fluid leaving the rotodynamic compressor 11 is then separated from the second phase in the separator 51. The second phase is stored in the tank 31. The gas is then mixed with the second phase coming from the tank 36, in the mixer 42. The fluid thus formed is compressed in the rotodynamic compressor 12, which makes it possible to maintain, or even improve, the mixture. Thus, the compression is quasi-isothermal. The compressed fluid leaving the rotodynamic compressor 12 is then separated from the second phase in the separator 52. The second phase is stored in the tank 32. The gas is then mixed with the second phase coming from the tank 37, in the mixer 43. The fluid thus formed is compressed in the rotodynamic compressor 13, which makes it possible to maintain, or even improve, the mixture. Thus, the compression is quasi-isothermal. The compressed fluid leaving the rotodynamic compressor 13 is then separated from the second phase in the separator 53. The second phase is stored in the tank 33. The compressed gas coming from the separator 53 can then be stored in the tank 30. On the [ Fig 3], the tanks 35, 31, 36, 32, 37 and 33 of the second phase are distinct but it could be envisaged that some of them consist of a common tank or alternatively of a single tank for all these. second phase tanks. [Fig 4] schematically and non-limitingly shows another variant of a second part relating to the energy recovery of the system. This second part can be combined with the first part of FIG. 3 to form a system for storing and recovering energy by compressed gas. The references identical to those in [Fig 2] correspond to the same elements and will therefore not be re-detailed.

Unlike [Fig 2] where a single expansion stage was produced via the rotodynamic expansion means 2, [Fig 4] has three rotodynamic expansion stages 23, 22 and 21. This stage allows more efficient outputs by a lower pressure variation across the terminals of each rotodynamic expansion means 21, 22, and 23. In addition, this characteristic allows the use of multiphase rotodynamic expansion means and to improve the performance of the system.

Just upstream of each expansion stage, a second phase is mixed with the gas and just downstream of each compression stage, the second phase is separated from the gas. Thus, temperature control can be optimal in each expansion stage, so as to achieve a quasi-isothermal transformation. Thus, the compressed gas leaving the reservoir 30 is first mixed with the second phase issuing from the reservoir 330, in the mixer 47. The fluid thus formed is expanded in the rotodynamic expansion means 23, which makes it possible to maintain, or even to improve the mixture. Thus, the compression is almost isothermal. The partially expanded fluid at the outlet of the rotodynamic expansion means 23 is then separated from the second phase in the separator 57. The second phase is stored in the tank 370. Then the gas is mixed with the second phase from the tank 320, in the mixer 46. The fluid thus formed is compressed in the rotodynamic expansion means 22, which makes it possible to maintain or even improve the mixture. Thus, the relaxation is quasi-isothermal. The compressed fluid leaving the rotodynamic expansion means 22 is then separated from the second phase in the separator 56. The second phase is stored in the tank 360. The gas is then mixed with the second phase coming from the tank 310, in the mixer 45. The fluid thus formed is expanded in the rotodynamic expansion means 21, which makes it possible to maintain or even improve the mixture. Thus, the relaxation is quasi-isothermal. The compressed fluid at the outlet of the rotodynamic expansion means 21 is then separated from the second phase in the separator 55. The second phase is stored in the reservoir 350. In [Fig 4], the reservoirs 350, 310, 360, 320, 370 and 330 of the second phase are distinct but it could be envisaged that some of them consist of a common reservoir or alternatively of a single reservoir for all these second phase reservoirs. It could also be envisaged that some of them and / or some of the reservoirs 35, 31, 36, 32, 37 and 33 of [Fig 3] are the same reservoir, or even that they all constitute a single and unique reservoir. , so as to limit the number of tanks and their cost. [Fig 5] is a variant of [Fig 3]. The references identical to those in [Fig 3] correspond to the same elements and will therefore not be re-detailed. In the variant of [Fig 5], the compressed gas leaving the separator 53 is stored in the tank 3. The second phase leaving the separator 53 is stored in the lower part of the tank 3 while the gas is stored in the upper part of the reservoir 3. Alternatively, at the outlet of the rotodynamic compressor 13, the mixture can be stored directly in the reservoir 3, without passing through a separator 53. In fact, in this case, the two phases will separate “naturally” at the end of a certain time. The separation by the separator 53 nevertheless makes it possible to ensure a better ordered storage in the tank 3 and easier to activate quickly, without requiring sufficient time between the charge and the discharge of the system to wait for the good separation of the phases in the tank 3. .

When the separator 53 is used upstream of the tank 3, the tank 3 can include a phase separation membrane. Although this membrane is not essential, it allows better preservation of phase separation.

[Fig 6] shows an example of a means of compression or rotodynamic expansion. The system can be used in one direction (direction of the black arrow F, the direction of the arrow F corresponds to the direction of fluid flow here, for the case of compression) for the compression and in the reverse direction for the relaxation. The operation shown corresponds to compression. As the trigger works in the opposite direction, it will not be detailed.

The rotodynamic compression means 120 comprises a hub 103 whose external diameter increases progressively, in the direction of arrow F, in order to generate the compression. One or more blades 102 are rigidly fixed to the hub 103. When the hub 103 is in rotation around the longitudinal axis AA of the rotodynamic compression means 120, for example driven by a rotation shaft (not visible), the blades 102 are rotating around axis AA. This rotation of the blades promotes mixing of the two phases. The rotodynamic compression means 120 also comprises an outer casing 100, preferably cylindrical. On the inner surface of this outer casing, are positioned rectifiers 101, the rectifiers 101 being rigidly attached to the outer casing 100.

The rotodynamic compression means 120 is therefore a succession of compression stages (via the vanes 101) and rectifiers 102 in the direction F. In FIG. 6, for example, the rotodynamic compression means comprises a first compression stage 102 , a first rectifier 101, a second compression stage 102, a second rectifier 101, a third compression stage 102 and a third rectifier 101, in the direction of flow F. The presence of the rectifiers tends to limit the centrifugal effect after each compression stage and therefore to further promote mixing between the gas and the second phase.

This type of rotodynamic compression means is particularly suitable for multiphase operation, in particular when mixing gas and liquid.

According to an alternative not shown, the invention may consist in using a two-phase rotodynamic compressor by injecting the second phase directly into the rectifiers of each of the stages. This makes it possible to eliminate the mixing means upstream of the rotodynamic compression means and thus to reduce costs.

Claims

1. A system for storing and recovering energy by compressed gas comprising at least one means of rotodynamic compression (1, 11, 12, 13) of fluid, at least one means of storage of compressed gas (30), at least one means for rotodynamic expansion (2, 21, 22, 23) of said compressed fluid to generate energy, characterized in that said fluid comprises said gas and a second phase and in that the system comprises means for injecting said second phase upstream or inside at least one rotodynamic compression means (1, 11, 12, 12), and / or upstream or inside at least one rotodynamic expansion means (2, 21, 22, 23).

2. The energy storage and recovery system according to claim 1, wherein the system comprises at least one separation means (51, 52, 53, 55, 56, 57) positioned after the rotodynamic compression means (1, 11, 12, 12) or after the rotodynamic expansion means (2, 21, 22, 23).

3. Energy storage and recovery system according to one of the preceding claims, wherein said second phase is a liquid, preferably water.

4. Energy storage and recovery system according to one of the preceding claims, for which the system comprises at least one storage means of said second phase (31, 32, 33, 35, 36, 37, 33B, 35B , 330, 370, 320, 360, 310, 350), said means for storing said second phase (31, 32, 33, 35, 36, 37, 33B, 35B, 330, 370, 320, 360, 310, 350 ) being connected to at least one injection means or to at least one separation means (51, 52, 53, 55, 56, 57).

5. Energy storage and recovery system according to one of the preceding claims for which each injection means and / or each separation means (51, 52, 53, 55, 56, 57) is connected to a means. for storing said second liquid phase (31, 32, 33, 35, 36, 37, 33B, 35B, 330, 370, 320, 360, 310, 350) different.

6. Energy storage and recovery system according to one of claims 1 to 4 for which each injection means and / or each separation means (51, 52, 53, 55, 56, 57) are connected to means for storing said second phase (31, 32, 33, 35, 36, 37, 33B, 35B, 330, 370, 320, 360, 310, 350), said means for storing said second phase (31, 32 , 33, 35, 36, 37, 33B, 35B, 330, 370, 320, 360, 310, 350) which may be common to several injection means and / or separation means (51, 52, 53, 55, 56 , 57).

7. Energy storage and recovery system according to claim 6, for which all the injection means and / or all the separation means (51, 52, 53, 55, 56, 57) are connected to a single storage means of said second phase (31, 32, 33, 35, 36, 37, 33B, 35B, 330, 370, 320, 360, 310, 350).

8. Energy storage and recovery system according to one of the preceding claims, wherein the system comprises at least one mixing means (41, 42, 43, 45, 46, 47) upstream of at least one rotodynamic compression means (1, 11, 12, 12) and / or separation means (51, 52, 53, 55, 56, 57) downstream of at least rotodynamic compression means (1, 11, 12, 12).

9. Energy storage and recovery system according to one of the preceding claims, for which the system comprises at least one mixing means (41, 42, 43, 45, 46, 47) upstream of at least one rotodynamic expansion means (2, 21, 22, 23) and / or a separation means (51, 52, 53, 55, 56, 57) downstream of at least one rotodynamic expansion means (2, 21, 22 , 23).

10. Energy storage and recovery system according to one of claims 8 or 9 for which at least one mixing means (41, 42, 43, 45, 46, 47) is integrated with at least one compression means. rotodynamic (1, 11, 12, 12) or at least one rotodynamic expansion means (2, 21, 22, 23).

11. A method of storing and recovering energy by compressed gas comprising the following steps: a1) a gas is compressed by means of rotodynamic compression; b1) said compressed gas is stored; c1) said compressed gas is expanded by a rotodynamic expansion means; characterized in that during or before the compression or expansion steps, a second phase is injected into said gas.

12. A method of storing and recovering energy by compressed gas according to claim 11, wherein said second phase is a liquid, preferably water.

13. A method for storing and recovering energy by compressed gas according to one of claims 11 or 12, for which step a1) is successively repeated several times.

14. A method for storing and recovering energy by compressed gas according to one of claims 11 to 13, for which step c1) is successively repeated several times.

15. A method for storing and recovering energy by compressed gas according to one of claims 11 to 14, for which said second phase is mixed with the compressed gas, between the injection of the second phase and the compression or the compression. relaxation.

16. A method for storing and recovering energy by compressed gas according to one of claims 11 to 15, for which said second phase and said compressed gas are separated, after the compression or expansion step.