METHOD AND INSTALLATION FOR STORING AND RECOVERING ENERGY

Abstract

A method and installation for storing and recovering energy, according to which a condensed air product is formed in an energy storage period, and in an energy recovery period, a pressure flow is formed and is expanded to produce energy using at least part of the condensed air product. For the formation of the condensed air product: the compression of air in an air conditioning unit, at least by means of at least one isothermally operated compressor device and the adsorptive cleaning of the air by means of at least one adsorptive cleaning device at a hyperbaric pressure level.

Claims

1. A method for storing and recovering energy in which, in an energy storage period, an air liquefaction product is formed and, in an energy recovery period, a pressurized stream is formed and expanded to perform work by using at least part of the air liquefaction product, the method comprising, for the formation of the air liquefaction product, compressing air in an air conditioning unit, at least by means of at least one isothermally operated compressor device, and adsorptively purifying the air by means of at least one adsorptive purification device at a superatmospheric pressure level, liquefying the compressed and adsorptively purified air, starting from a temperature level in a range of 0 to 50 C., in a first fraction in a fixed-bed cold storage unit and in a second fraction in a counterflow heat exchanger unit at a liquefaction pressure level in a range of 40 to 100 bara, and subsequently expanding the liquefied air in at least one cold production unit, and, for the formation of the pressurized stream, producing a vaporization product from at least part of the liquefaction product at a vaporization pressure level, which deviates by no more than 5 bar from the liquefaction pressure level, in the fixed-bed cold storage unit, and forming a fluid stream from at least part of the vaporization product and conducting it through at least one combustion device, in which a fuel is burned.

2. The method as claimed in claim 1, which comprises expanding the fluid stream conducted through the at least one combustion device in at least one generator turbine as the pressurized stream.

3. The method as claimed in claim 2, which comprises using at least one expansion turbine of at least one gas turbine unit as the at least one generator turbine.

4. The method as claimed in claim 1, which comprises heating, expanding and/or compressing the fluid stream at least one time before it is conducted through the combustion device.

5. The method as claimed in claim 1, which comprises feeding to the at least one adsorptive purification device a regenerating gas, which is formed from part of the air that is previously compressed and adsorptively purified in the air conditioning unit.

6. The method as claimed in claim 5, which comprises forming the regenerating gas during the energy storage period from at least part of an evaporation product formed during the expansion of the liquefied air.

7. The method as claimed in claim 5, which comprises forming the regenerating gas during the energy recovery period from at least part of the vaporization product.

8. The method as claimed in claim 1, which comprises conducting an evaporation product formed during the expansion of the liquefied air through the counterflow heat exchanger unit.

9. The method as claimed in claim 1, which comprises conducting at least one cold transfer medium that is provided by means of an external cold circuit and/or is formed by expansion from part of the air compressed and adsorptively purified in the air conditioning unit through the counterflow heat exchanger unit.

10. An installation, which is designed for storing and recovering energy by forming an air liquefaction product in an energy storage period and by generating, and expanding to perform work, a pressurized stream formed by using at least part of the air liquefaction product in an energy recovery period, the installation having means which are designed, for the formation of the air liquefaction product, to compress air in an air conditioning unit, at least by means of at least one isothermally operated compressor device, and adsorptively purify the air by means of at least one adsorptive purification device at a superatmospheric pressure level, to liquefy the compressed and adsorptively purified air, starting from a temperature level in a range of 0 to 50 C., in a first fraction in a fixed-bed cold storage unit and in a second fraction in a counterflow heat exchanger unit at a liquefaction pressure level in a range of 40 to 100 bara, and subsequently to expand the liquefied air in at least one cold production unit, and, for the formation of the pressurized stream, to produce a vaporization product from at least part of the liquefaction product at a vaporization pressure level, which deviates by no more than 5 bar from the liquefaction pressure level, in the fixed-bed cold storage unit, and to form a fluid stream from at least part of the vaporization product and to conduct it through at least one combustion device, in which a fuel is burned.

11. The installation as claimed in claim 10, which has means that are designed for carrying out a method for storing and recovering energy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIGS. 1A and 1B show an installation according to one embodiment of the invention in an energy storage period and an energy recovery period.

[0052] FIGS. 2A to 2F show an air conditioning unit and an energy production unit according to embodiments of the invention.

[0053] FIGS. 3A and 3B show cooling devices for air conditioning units according to embodiments of the invention.

[0054] FIG. 4 shows an air purification device for an air conditioning unit according to one embodiment of the invention.

[0055] FIG. 5 shows a compressor device with a regenerating gas preheating device for an air conditioning unit according to one embodiment of the invention.

[0056] FIGS. 6A and 6B show an air purification device in the energy storage period and the energy recovery period for an air conditioning unit according to specific embodiments of the invention.

[0057] FIG. 7 shows a regenerating gas preheating device for an air conditioning unit according to a specific embodiment of the invention.

[0058] FIGS. 8A to 8C show installations according to embodiments of the invention and illustrate details of an associated counterflow heat exchanger unit.

EMBODIMENTS OF THE INVENTION

[0059] In the figures, elements, apparatuses, devices and fluid streams that correspond in principle to one another are illustrated by the same designations and, for the sake of overall clarity, are not newly explained in all cases.

[0060] A large number of valves are shown in the figures, some connected to allow a flow to pass through and some connected to stop a flow. Valves connected to stop a flow are crossed through in the figures. Fluid streams that are interrupted by valves connected to stop a flow and correspondingly deactivated devices are mainly illustrated by dashed lines. Streams that are in a gaseous or supercritical state are illustrated by white (not filled-in) triangular arrowheads, liquid streams by black (filled-in) triangular arrowheads.

[0061] In FIGS. 1A and 1B, an installation according to a particularly preferred embodiment of the invention is shown in an energy storage period (FIG. 1A) and an energy recovery period (FIG. 1B) and is denoted overall by 100.

[0062] The installation 100 comprises as central components an air conditioning unit 10, a fixed-bed cold storage unit 20, a counterflow heat exchanger unit 30, a cold production unit 40, a liquid storage unit 50 and an energy production unit 60.

[0063] Here and hereinafter, some or all of the components shown may be present in any desired number and be charged for example in parallel with corresponding sub-streams.

[0064] In the energy storage period illustrated in FIG. 1A, an air stream a (AIR, feed air) is fed to the installation 100 and compressed and purified in the air conditioning unit 10. A stream b that has been correspondingly compressed and purified, in particular freed of water and carbon dioxide, is at a pressure level of for example 40 to 100 bara and is also referred to hereinafter as the high-pressure air stream b.

[0065] In the energy storage period of the installation 100 that is illustrated in FIG. 1A, the high-pressure air stream b is divided into a first sub-stream c and a second sub-stream d. It goes without saying that, in corresponding installations, it may also be provided that a corresponding high-pressure air stream b is divided into more than two sub-streams.

[0066] The air of the sub-streams c and d (HPAIR) is fed on the one hand to the fixed-bed cold storage unit 20 and on the other hand to the counterflow heat exchanger unit 30 at the already mentioned pressure level of the high-pressure air stream b and respectively liquefied in the fixed-bed cold storage unit 20 and the counterflow heat exchanger unit 30. The air of the correspondingly liquefied streams e and f (HPLAIR) is combined to form a collective stream g. The pressure level of the streams e, f and g corresponds substantially, i.e. apart from line losses and cooling losses, to the pressure level of the high-pressure air stream b.

[0067] The liquefied air of the stream g, that is to say an air liquefaction product, is expanded in the cold production unit 40, which may for example comprise a generator turbine 41. The expanded air may be transferred for example into a separator vessel 42, in the lower part of which a liquid phase is separated and in

[0068] The liquid phase can be drawn off from the separator vessel 42 as stream h (LAIR) and transferred into the liquid storage unit 50, which may for example comprise one or more isolated storage tanks. The pressure level of the stream h is for example at 1 to 16 bara. The gas phase drawn off from the upper part of the separator vessel 42 as stream i (flash) may be conducted in counterflow to the stream f through the counterflow heat exchanger unit 30 and subsequently, in the form of the stream k (LPAIR, reggas), be used in the air conditioning unit 10 as regenerating gas. The pressure level of the stream k is for example at atmospheric pressure to about 2 bara. Downstream, a corresponding stream I is typically at atmospheric pressure (amb) and may be discharged into the surroundings.

[0069] During the energy storage period illustrated in FIG. 1A, the cold stored in the fixed-bed cold storage unit 20 is used for liquefying the air of the sub-stream c. Additionally provided is the counterflow heat exchanger unit 30, in which additional air, specifically air of the sub-stream d, can be liquefied in counterflow to for example a cold stream i, which can be obtained from expanded, evaporated air of the stream g. Use of the counterflow heat exchanger unit 30 makes more flexible operation of the installation 100 possible than would be the case when using only the fixed-bed cold storage unit 20.

[0070] Furthermore, a stream j, which is likewise provided by means of the air conditioning unit 10 and is at a pressure level of for example 5 to 20 bara, is conducted through the counterflow heat exchanger unit 30. This stream j is also referred to hereinafter as the medium-pressure air stream (MPAIR).

[0071] In the energy recovery period illustrated in FIG. 1B, liquefied air (LAIR) previously stored in the energy storage period, that is to say the air liquefaction product, is removed from the liquid storage unit 50 and increased in pressure by means of a pump 51. A stream m (HPLAIR) obtained in this way is conducted through the fixed-bed cold storage unit 20 and thereby evaporated or transformed from the liquid state into the supercritical state (vaporized). A vaporization product is therefore formed, from which a fluid stream is formed completely, as shown here, or else only partially. The stream m is in this case at a comparable pressure level to the already previously explained high-pressure air stream b. The stream n obtained by the evaporation or the transformation from the liquid state into the supercritical state in the fixed-bed cold storage unit 20 is consequently also a high-pressure air stream.

[0072] In the energy recovery period illustrated in FIG. 1B, a fluid stream is formed from the high-pressure air stream n in the energy production unit 60, is heated by using fuel fed to the energy production unit 60 in a stream o and is expanded to obtain electrical energy. In this way, a pressure-increased pressurized stream is formed from the fluid stream, which for its part may also already have been pressurized. As also illustrated below, the expansion and the heating of a corresponding stream can take place in various ways. A correspondingly expanded stream p is for example at atmospheric pressure (amb) and can for example be passed on to an exhaust gas purification unit.

[0073] The air conditioning units 10 and energy production units 60 illustrated in FIGS. 2A to 2F are intended for use in installations 100 according to various embodiments of the invention, for example in the installation 100 shown in FIGS. 1A and 1B.

[0074] According to the embodiment shown in FIG. 2A, the already explained stream a is sucked in by way of a filter 11 and compressed by means of a compressor device 12, for example by means of a multi-stage axial compressor. After cooling down in an aftercooling device 13, for example in a cooler 13 operated with cooling water, the compressed and then cooled stream a is fed to a cooling device 14 and subsequently to an air purification device 15. Examples of corresponding cooling devices 14 and air purification devices 15 are illustrated more specifically in the subsequent FIGS. 3A, 3B and 4.

[0075] Downstream of the air purification device 15, a sub-stream of the air of the stream a at an intermediate pressure is removed as the already explained stream j. Air of the stream a that is not discharged as medium-pressure air stream j is compressed further in a further compressor device 16. The compressor device 16 may also be formed as a multi-stage axial compressor.

[0076] In the context of the present invention, in particular the compressor device 12 and the compressor device 16 may be charged with air at the same temperature. In particular, the compressor devices 12 and/or 16 may be operated isothermally.

[0077] Arranged downstream of the compressor device 16 is a further aftercooling device 17. Air compressed in the compressor device 16 and cooled in the aftercooling device 17 is provided as the already explained high-pressure air stream b.

[0078] For operating or regenerating the air purification device 15, the already explained regenerating gas stream k may be fed to it and the likewise explained stream I discharged from it.

[0079] As already explained with reference to FIGS. 1A and 1B, the high-pressure air stream b and the medium-pressure air stream j through the air-conditioning unit 10 are typically only provided in the energy storage period. In this energy storage period, the energy production unit 60 is not in operation. Conversely, in the energy recovery period, typically only the energy production unit 60 is in operation, but not the air conditioning unit 10. FIGS. 2A to 2F consequently show the energy storage period and the energy recovery period in one representation.

[0080] In the energy recovery period, the high-pressure air stream n is fed to the energy production unit 60 and heated in a recuperator system 61, which may for example be formed by a number of heat exchangers. The heated high-pressure air stream n is expanded in a generator turbine 62 to obtain electrical energy and subsequently conducted once again through the recuperator system 61 and heated in it.

[0081] A further heating of the expanded high-pressure air stream n takes place by means of fuel of the stream o, which can be burned in a combustion device 63, for example a combustion chamber. The correspondingly heated stream is fed to a further generator turbine 64 and expanded in it to obtain electrical energy. Part of the heat of the stream expanded in the generator turbine 64 is transferred in the recuperator system 61 to the already mentioned streams conducted through it. Downstream of the recuperator system 61, the stream expanded in the further generator turbine 64 is purified as stream p, as mentioned, for example in an exhaust gas purification unit.

[0082] The variant illustrated in FIG. 2B differs from this substantially in the design of the air conditioning unit 10. In particular, the cooling device 14 and the air purification device 15 are provided here downstream of the compressor device 16 and the associated aftercooling device 17, that is to say in a region of higher pressure. This is possible because no medium-pressure air stream j that likewise has to be purified is formed here. The cooling device 14 and the air purification device 15 are designed for a corresponding higher pressure. As mentioned, this makes it possible to make the air purification device 15 be of a smaller size.

[0083] With regard to the air conditioning unit 10, the variant illustrated in FIG. 2C corresponds substantially to the variant illustrated in FIG. 2A. However, illustrated in the energy production unit 60 is a gas turbine unit 65, the compression stage and expansion stage of which may be coupled to a generator by way of a common shaft, but are not individually denoted. In the variant illustrated in FIG. 20, the high-pressure air stream n is likewise conducted through a recuperator system 61 and expanded in a generator turbine 62. The correspondingly expanded stream, here denoted by q, is fed to the compression stage of the gas turbine unit 65, subsequently heated by fuel of the stream o in an interposed combustion device 63 and then expanded in an expansion stage of the gas turbine unit 65. The heat produced in the gas turbine unit 65 or the combustion device 63 is at least partly transferred to the high-pressure air stream n in the recuperator system 61.

[0084] The variant illustrated in FIG. 2D corresponds substantially to a combination of the air conditioning unit 10 shown in FIG. 2B and the energy production unit 60 shown in FIG. 2C. For details, reference is therefore made to the previously explained FIGS. 2B and 2C.

[0085] The variant illustrated in FIG. 2E differs from the variant illustrated in FIG. 2B substantially in the use of the regenerating gas stream k. In the variant illustrated in FIG. 2E, this regenerating gas stream k is not provided as a low-pressure air stream but as a high-pressure air stream. It may for example be formed from part of the high-pressure air stream n, i.e. during the energy recovery period. Here, the regenerating gas stream k is first conducted through the air purification device 15 (which in the energy recovery period is not operating in a purifying mode and consequently can be regenerated) and subsequently combined with the high-pressure air stream n. Components contained in the stream I downstream of the air purification device 15, such as water and carbon dioxide, generally prove to be unproblematic on account of the temperatures that prevail in the energy production unit 60. The variant illustrated in FIG. 2E has the advantage that less compressed air is lost.

[0086] The variant illustrated in FIG. 2F likewise comprises the already explained different use of the regenerating gas stream k that is already shown in FIG. 2E. As shown in FIG. 2F, this variant is suitable in the same way for use with an energy production unit 60 with a gas turbine unit 65, not just with the expansion of the stream n according to FIG. 2A or FIG. 2B that is shown in FIG. 2E.

[0087] In FIG. 3A, a cooling device 14 for use in an air conditioning unit 10, such as that illustrated for example in the previously shown FIGS. 2A to 2F, is shown in detail. The cooling device 14 may be arranged downstream of the aftercooling device 13 (cf. FIGS. 2A and 2C) or downstream of the aftercooling device 17 (cf. FIGS. 2B, 2D, 2E and 2F). A corresponding stream, here denoted by r, is fed into a lower region of a direct contact cooler 141. The stream r corresponds to the correspondingly compressed stream a (cf. FIGS. 2A to 2F). In an upper region of the direct contact cooler 141, a water stream (H2O), which is conducted through an (optional) cooling device 143 by means of a pump 142, is introduced. Water can be drawn off from a lower region of the direct contact cooler 141. A correspondingly cooled stream s is drawn off from the head of the direct contact cooler 141 and can for example subsequently be transferred into an air purification device 15 (cf. FIGS. 2A to 2F).

[0088] As a departure, according to the variant of the cooling device 14 that is illustrated in FIG. 3B, a direct contact cooler 141 is not provided, but instead a heat exchanger 144. This heat exchanger 144 may also be operated with a water stream, which is conducted through an (optional) cooling device 143 by means of a pump 142.

[0089] In FIG. 4, an air purification device 15, which is suitable in particular for use in an air conditioning unit 10, such as that shown in FIGS. 2A to 2D, is illustrated in detail. A cooled stream s, originating for example from a cooling device 14 (cf. FIGS. 2A to 2D and FIGS. 3A and 36), may be conducted here alternately through two adsorber vessels 151, which for example comprise a molecular sieve. The stream s corresponds in this case to the correspondingly compressed and cooled stream a (cf. FIGS. 2A to 2D). In the adsorber vessels 151, water and carbon dioxide in particular are removed from the stream s. A correspondingly obtained stream t, which for example in the case of the embodiments illustrated in FIGS. 2B and 2D may correspond to the stream b, is fed to the device respectively arranged downstream of it, for example the next compressor device (cf. FIGS. 2A and 2C) or the fixed-bed cold storage unit 20 or the counterflow heat exchanger unit 30 (cf. FIGS. 2B and 2D).

[0090] The adsorber vessel 151 that is respectively not being used for purifying the stream s may be regenerated by means of the already explained regenerating gas stream k. The stream k may in this case first be fed to an optional regenerating gas preheating device 152, which is illustrated in an example in the subsequent FIG. 5. In a downstream regenerating gas heating device 153, which may for example be operated electrically and/or with hot steam, the regenerating gas stream k is heated further and conducted through the adsorber vessel 151 that is respectively to be regenerated. Downstream of the adsorber vessel 151 to be regenerated there is a corresponding stream I. The same applies if no regenerating gas is needed at the time shown, because in this case a corresponding stream I is discharged directly from the air purification device 15 (see stream I in the upper part of FIG. 4).

[0091] In FIG. 5, the operation of a regenerating gas preheating device 152 according to one embodiment of the invention is illustrated in particular. The regenerating gas preheating device 152 may for example replace or supplement one of the aftercooling devices 13 or 17, and consequently be arranged downstream of an air compressor device 12 or 16. An air stream heated as a result of a corresponding compression may be conducted through a heat exchanger 152a of the regenerating gas preheating device 152 or past it, and thereby transfer heat to a regenerating gas stream k.

[0092] Shown in FIGS. 6A and 6B are air purification devices 15, which are suitable in particular for the embodiments of the present invention illustrated in FIGS. 2E and 2F and the air conditioning devices shown in them. In FIGS. 6A and 6B, the energy storage period (FIG. 6A) and the energy recovery period (FIG. 6B) are illustrated, the purification of a corresponding stream s taking place in the energy storage period. Because in the energy recovery period a corresponding installation 100 is not fed air in the form of the stream a, and consequently the air conditioning device 10 is not in operation, at such times a corresponding adsorber vessel 151 is available for regeneration. The embodiment illustrated in FIGS. 6A and 6B therefore has the particular advantage that only one corresponding adsorber vessel 151 has to be provided, and not two, which according to FIG. 4 are operated alternately. As shown in FIGS. 2E and 2F, this requires the provision of a corresponding regenerating gas stream k during the energy recovery period.

[0093] Here, too, a regenerating gas stream k may be preheated in an optional regenerating gas preheating device 152, which is illustrated in detail in FIG. 7, and heated in a regenerating gas heating device 153.

[0094] In the energy recovery period illustrated in FIG. 6B, correspondingly heated regenerating gas is consequently conducted through the adsorber vessel 151; in the energy storage period, this regenerating gas vessel 151 is available for purifying the stream s.

[0095] As mentioned, illustrated in FIG. 7 is a regenerating gas preheating device 152, which is suitable in a particular way for use in the air purification device 15 shown in FIGS. 6A and 6B. The regenerating gas stream k is conducted here through the recuperator system 61 already illustrated in FIGS. 2E and 2F in counterflow in relation to the explained stream n (and additionally in relation to the medium-pressure air stream j).

[0096] FIGS. 8A to 8C illustrate installations according to preferred embodiments of the invention in each case in the energy storage period. The installations correspond substantially to the previously explained embodiments with respect to the fixed-bed cold storage unit 20, the cold production unit 40, the liquid storage unit 50 and the energy production unit 60, but differ in particular with regard to the counterflow heat exchanger unit 30, which is therefore explained below.

[0097] According to the embodiment illustrated in FIG. 8A, the counterflow heat exchanger unit 30 may for example be operated by means of a stream u, which is conducted from the cold end to the warm end through one or more heat exchangers 31 of the counterflow heat exchanger unit 30.

[0098] To provide the stream u, a separate liquefaction process 32, operated by means of dedicated compressors, i.e. compressors provided in addition to the air-conditioning unit 10, may for example be implemented.

[0099] In the embodiment shown in FIG. 8B, which corresponds substantially to the embodiment shown in FIGS. 1A and 1B, on the other hand, a medium-pressure air stream j may be fed to the the counterflow heat exchanger unit 10 and fed into the heat exchanger 31 at the warm end. The stream j may be removed from the heat exchanger 31 at an intermediate temperature and expanded in a generator turbine 33. A further sub-stream of the high-pressure air stream b, or its sub-stream d, may likewise be removed from the heat exchanger 131 at an intermediate temperature and expanded in a further generator turbine 34. Said flows may be combined and conducted together through the generator turbine 33. Cold released by the expansion is used for the liquefaction of the stream c (see FIGS. 1A and 1B), in that corresponding streams are fed on the cold side to the heat exchanger 31 together with the already explained stream i.

[0100] In a variant shown in FIG. 8C, the stream i is fed on the cold side to the heat exchanger 31 of the counterflow heat exchanger unit 30, removed at an intermediate temperature, combined with the medium-pressure air stream j, which has likewise been conducted through the heat exchanger 31 up to an intermediate temperature, and subsequently expanded in the generator turbine 33. Previously, corresponding air may be combined with a sub-stream of the stream c, as already shown in FIG. 8B.

[0101] The embodiments illustrated in FIGS. 8B and 8C are suitable in particular for the use of streams i at different pressure levels.