SYSTEM HAVING A LIQUID AIR ENERGY STORAGE AND POWER PLANT APPARATUS

Abstract

The invention relates to a system (10) having a liquid air energy storage and power plant apparatus (12), having a charging component (16) comprising a compressor (26) for compressing supplied air and comprising a liquefier (40) which adjoins said compressor and which serves for liquefying the air. According to the invention, an apparatus (14) for permanent water electrolysis having at least one first heat exchanger (94, 96) is provided, by means of which the heat energy generated during the electrolysis is absorbed by a fluid flowing through the first heat exchanger (94, 96).

Claims

1-24. (canceled)

25. System (10), comprising: a liquid air energy storage and power plant apparatus (12), having a charging component (16) comprising a compressor (26) for compressing supplied air and comprising a liquefier (40), which adjoins said compressor and which serves for liquefying the air, a storage component comprising an air storage (18) for storing the liquefied air, and a discharging component (20) comprising an evaporation apparatus (62) for converting liquid air into gaseous compressed air, wherein heat energy is supplied to the evaporation apparatus (62) via a first heat line (68), and comprising an expansion apparatus which serves for expanding the compressed air and which has a turbine (76) and a generator (78) which is connected to the turbine (76); and an apparatus (14) for permanent water electrolysis having at least one first heat exchanger (94, 96), by means of which the heat energy generated during the electrolysis is absorbed by a fluid flowing through the first heat exchanger (94, 96), which first heat exchanger (94, 96) is connected to the first heat line (68) in such a way that the heat energy generated during the electrolysis is dissipated via the first heat exchanger (94, 96) by means of the fluid and is fed to the evaporation apparatus (62).

26. System according to claim 25, characterized in that the evaporation apparatus is a water bath evaporation apparatus (62).

27. System according to claim 25, characterized in that two first heat exchangers (94, 96) are provided, of which one first heat exchanger (94) is associated with oxygen recovery and the other first heat exchanger (96) is associated with hydrogen recovery in the apparatus (14) for permanent water electrolysis.

28. System according to claim 25, characterized in that the apparatus (14) for permanent water electrolysis is a proton exchange membrane electrolyzer (Proton Exchange Membrane or Polymer Electrolyte Membrane, or PEM in short).

29. System according to claim 25, characterized in that the apparatus (14) for permanent water electrolysis is designed as an alkaline electrolyzer.

30. System according to claim 25, characterized in that the compressor (26) of the charging component (16) cooperates with at least one second heat exchanger (32), the fluid of which flowing through the second heat exchanger (32) absorbs and dissipates the heat energy generated during compression of the air.

31. System according to claim 30, characterized in that the second heat exchanger (32) is connected to the evaporation apparatus (62) via a second heat line (36) in order to supply the heat energy generated during compression to the evaporation apparatus (62).

32. System according to claim 25, characterized in that at least one third heat exchanger (64) is connected downstream of the evaporation apparatus (62), which third heat exchanger (64) is used to supply further thermal energy to the compressed air from the evaporation apparatus (62) and to set the required temperature of the compressed air.

33. System according to claim 32, characterized in that the evaporation apparatus (62) is connected to the third heat exchanger (64) via the first heat line (68) and/or the second heat line (36) and uses the remaining heat energy of the fluid exiting the evaporation apparatus (62) to set the temperature of the compressed air via the third heat exchanger (64).

34. System according to claim 32, characterized in that the third heat exchanger (64) is designed as an air-water heat exchanger.

35. System according to claim 32, characterized in that the third heat exchanger (64) is connected to the first heat exchanger (94, %) via the first heat line (68) and forms a first fluid circuit (98).

36. System according to claim 25, characterized in that the third heat exchanger (64) is connected to the second heat exchanger (32) via the second heat line (36) and forms a second fluid circuit (38).

37. System according to claim 25, characterized in that a compressed air buffer tank (66) is provided in the discharging component (20) of the liquid air energy storage and power plant apparatus (12).

38. System according to claim 32, characterized in that the third heat exchanger (64) is connected upstream of the compressed air buffer tank (66).

39. Method of operating a system (10) comprising a liquid air energy storage and power plant apparatus (12) and an apparatus (14) for permanent water electrolysis, in particular a system (10) according to any one of the preceding claims, wherein the thermal energy of the waste heat of the apparatus (14) for permanent water electrolysis is used to supply it to an evaporation apparatus (62) of a discharging component (20) of the liquid air energy storage and power plant apparatus (12) for the conversion of liquefied air into gaseous compressed air.

40. Method according to claim 39, characterized in that the heat energy of the waste heat of an electrolyzer (80) is used by the apparatus (14) for permanent water electrolysis.

41. Method according to claim 39, characterized in that additionally the thermal energy of a compressor (26) is used for compressing supplied air of a charging component (16) of the liquid air energy storage and power plant apparatus (12) in order to supply it to the evaporation apparatus (62) of the discharging component (20) of the liquid air energy storage and power plant apparatus (12) for the conversion of liquefied air into gaseous compressed air.

42. Method according to claim 39, characterized in that the evaporation apparatus (62) of the discharging component (20) of the liquid air energy storage and power plant apparatus (12) is supplied with the thermal energy via a fluid.

43. Method according to claim 42, characterized in that the fluid is supplied to the evaporation apparatus (62) at a temperature of between 40° C. and 90° C.

44. Method according to claim 39, characterized in that the thermal energy is constantly supplied to the evaporation apparatus (62) of the discharging component (20) via the first heat line (68), and liquefied air is converted into gaseous air in the evaporation apparatus (62) as required and supplied to a compressed air buffer storage (66).

45. Method according to claim 39, characterized in that the gaseous compressed air from the compressed air buffer storage (66) is supplied as required to an expansion device having a turbine (76) with a generator (78) connected thereto, in order to drive the turbine (76) and the generator (78) thereby and to supply power generated by the generator (78) to the existing power grid (22).

46. Method according to claim 39, characterized in that the fluid of the first heat line (68) is cooled before it enters the first heat exchanger (94, 96).

47. Method according to claim 39, characterized in that the fluid of the second heat line (36) is cooled before it enters the second heat exchanger (32).

48. Method according to claim 39, characterized in that energy from renewable sources is used for the liquid air energy storage and power plant apparatus (12) and/or the apparatus (14) for permanent water electrolysis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In the drawings,

[0043] FIG. 1 is a schematic view of a system according to an embodiment of the invention;

[0044] FIG. 2 is another schematic detail view comprising two water bath evaporation devices connected in series and an air/water cooler of a discharging component connected thereto in cooperation with two fluid circuits of the system according to the invention, and

[0045] FIG. 3 is another schematic view of the modular structure of the system according to the invention.

DESCRIPTION OF THE INVENTION

[0046] Illustrated in FIG. 1 is a system 10 according to an embodiment of the invention. The system 10 comprises a liquid air energy storage and power plant apparatus 12 and an apparatus 14 for permanent water electrolysis.

[0047] The liquid air energy storage and power plant apparatus 12 is essentially includes three main components, namely a charging component 16, a storage component in the form of a liquid air storage 18, and a discharging component 20.

[0048] Electric power is supplied to an electric motor 24 of the charging component 16 from a power grid 22, which motor 24 is connected to and drives a compressor 26 as needed. An air intake filter 28 is connected upstream of the compressor 26, through which ambient air, among other things, is supplied to the compressor 26 during operation of the charging component 16.

[0049] Via an air line 30, the air compressed by the compressor 26 is fed to a dryer 34 via a second heat exchanger 32 of the charging component 16. With the aid of the second heat exchanger 32 of the charging component 16, thermal energy is extracted from the compressed air which is heated by the compression. For this purpose, the second heat exchanger 32 of the charging component 16 is connected to a second heat line 36 of a second fluid circuit 38 for dissipating heat energy. This will be discussed later.

[0050] In the dryer 34, the compressed air is cleaned of water vapor, hydrocarbons and carbon dioxide in a manner known per se.

[0051] The compressed air is then fed to an air liquefier 40, which includes a heat exchanger 42, a regulating valve 44, an expansion turbine 46 with a brake generator 48 connected thereto to generate electricity, an expansion valve 50, and an expansion tank 52. In the air liquefier 40, the compressed and dried air is first fed to the heat exchanger 42. In the heat exchanger 42, a first partial flow of the compressed air is branched off and directed to the expansion turbine 46 via the regulating valve 44, where the compressed air then expands to ambient pressure and thus drives the expansion turbine 46. The expansion turbine 46 in turn drives the brake generator 48 which generates electricity and transmits it via an electrical control center 54 with inverter, transformer, etc. to the power grid 22 or to the loads of the system 10, for example the compressor 26.

[0052] Next, the now strongly cooled air coming from the expansion turbine 46 is fed to the heat exchanger 42 where it extracts a considerable amount of heat energy from the second partial flow, thus cooing it down significantly. The first partial flow thus heated is returned to the air intake filter 28 via the dryer 34 and in this way fed back to the compressor 26.

[0053] In the heat exchanger 42, the second partial flow is cooled to just before the liquefaction point and is then passed through an expansion valve 50, where the air then drops to below the liquefaction point and enters the expansion tank 52. Via the expansion tank 52 and another regulating valve 56, liquid air is then introduced into the air storage 18 at ambient pressure and at approximately −190° C. In the air storage 18, the liquid air is stored until energy is required for balancing peak loads.

[0054] For extracting energy, liquid air is extracted from the air storage 18 by a pump 58 which is driven by a motor 60. Via air line 30, liquid air is first fed to an evaporation device in the form of a water bath evaporation device 62, and is then fed in the form of compressed air to a third heat exchanger 64, and finally as compressed air to a compressed air buffer tank 66. In the water bath evaporation device 62, heat energy is supplied to the water bath evaporation device 62 via both a first heat line 68 and the second heat line 38, so that liquid air is converted into compressed air and then has a pressure of approx. 40 bar. In the third heat exchanger 64, the compressed air is heated to ambient temperature or warmer and then stored in the compressed air buffer tank 66. The process of extracting liquid air from the air storage 18 and supplying compressed air may be a continuous one.

[0055] For easy adjustment of the temperature of the compressed air supplied to the compressed air buffer tank 66, a bypass line 70 is additionally provided, in which a bypass valve 72 is inserted. The bypass fine 70 is connected to the part of the air line 30 that connects the water bath evaporation device 62 to the third heat exchanger 64. In addition, the bypass line 70 is connected to the part of the air line 30 that connects the third heat exchanger 64 to the compressed air buffer tank 66. In this manner, colder compressed air from the water bath evaporation device 62 can be mixed with warmer compressed air from the third heat exchanger 64, thus allowing the temperature of the compressed air that is introduced into the compressed air buffer tank 66 to be adjusted in a predetermined manner.

[0056] In the compressed air buffer tank 66, the compressed air supplied via air line 30 is continuously stored until such time when energy is required, for example, for balancing peak loads in the power grid 22. For this purpose, the compressed air buffer tank 66 is connected to a main turbine 76 with an attached power generator 78 via a pneumatic valve 74 and another part of air line 30. In the main turbine 76, the compressed air expands from about 40 bar to ambient pressure, thereby driving the main turbine 76 with the power generator 78 connected thereto to generate electricity. The electricity generated is supplied to the power grid 22 for regulation.

[0057] The apparatus 14 for permanent water electrolysis consists of several PEM 80 electrolyzers, which are connected to the power grid 22 from where they receive the electrical energy for permanent water electrolysis for H2 and O2 production. For at least 7,000-8,000 hours a year, the PEM 80 electrolyzers continuously produce hydrogen and oxygen 24h a day. The oxygen is supplied to an oxygen storage tank 88 and the hydrogen is supplied to a hydrogen storage tank 86 and is further processed or transferred as needed in a manner known per se. The heat energy generated during oxygen production as well as during hydrogen production is dissipated through fluid circuits 90, 92, and is dissipated via a heat exchanger 94 associated with the oxygen production fluid circuit 92, and via a heat exchanger 96 associated with the hydrogen recovery fluid circuit 92.

[0058] The first heat line 68 connects the first two heat exchangers 94 and 96 to one another and absorbs the heat energy from the fluid circuits 90 and 92 through the fluid flowing in the heat line 68.

[0059] The heat line 68 forms a first fluid circuit 98. More specifically, the heat line 68 runs from the two first heat exchangers 94, 96 to the water bath evaporation device 62 in order to there release the heat energy stored in the fluid of heat line 68 to a water bath, via which the liquefied air of air line 30 is heated again and caused to evaporate.

[0060] Heat line 68 continues from the water bath evaporation device 62 to the third heat exchanger 64 and back to the two first heat exchangers 94 and 96. The first fluid circuit 98 formed by the first heat line 68 is thus a closed circuit.

[0061] Moreover, a bypass line 100 having a bypass valve 102 of the first fluid circuit 98 is provided, which short-circuits the first heat line 68 while bypassing the third heat exchanger 64. This is a simple way of adjusting the heat energy to be supplied to the compressed air in air line 30 by the fluid in the first heat line 68 via the third heat exchanger 64.

[0062] In addition, an equalizing line 104 with an equalizing valve 106 is provided which connects the part of the first heat line 68 downstream of the third heat exchanger 64 to the part of the second heat line upstream of the second heat exchanger 32. This is to transfer fluid from the first heat line 68 of the first fluid circuit 98 to the second heat line 36 of the second fluid circuit 38, thereby introducing heat energy from the first fluid circuit 98 into the second fluid circuit 38. This serves to regulate the return temperature of the second heat line 36 during operation of the charging component 16.

[0063] FIG. 2 is a schematic view of substantially the first fluid circuit 98 and the second fluid circuit 38. The individual components have the parts of the system 10 as described with reference to FIG. 1. For reasons of clarity, however, these have been omitted from the view of FIG. 2.

[0064] The first heat line 68 runs from the first heat exchangers 94, 96 of the apparatus 14 for permanent hydrogen electrolysis to two water bath evaporation devices 62a, 62b connected in series, then on to the third heat exchanger 64 in the form of an air/water cooler, and finally back to the first heat exchangers 94, 96. For reasons of clarity, bypass line 100 with bypass valve 102, but also equalizing line 104 with equalizing valve 106 are not shown here.

[0065] The second heat line 36 extends from the second heat exchanger 32 at the compressor 26 to the first water bath evaporation device 62a, subsequently to the second water bath evaporation device 62b, then on to the third heat exchanger 64 and back to the second heat exchanger 32.

[0066] Moreover, the air storage 18 is shown with air line 30. Air line 30 runs from the air storage 18 via the two water bath evaporation devices 62a, 62b via the third heat exchanger 64 to the compressed air buffer tank 66.

[0067] A fan is provided in the third heat exchanger 64 for cooling the fluid of the first heat line 68 before it enters the first heat exchanger 94, 96, and for cooling the fluid of the second heat line 36 before it enters the second heat exchanger 32.

[0068] This clearly shows that the waste heat from the apparatus 14 for permanent hydrogen electrolysis and the waste heat from the compressor 26 are used as thermal energy that is continuously supplied to the discharging component 20 via the water bath evaporation devices 62a, 62b and the third heat exchanger 64 in a 24 hour/7 days a week mode of operation.

[0069] FIG. 3 is a schematic view of the basic structure of the system 10 described with reference to FIGS. 1 and 2. As shown, this system 10 has two liquid air energy storage and power plant apparatuses 12 arranged in parallel.

[0070] Furthermore illustrated in FIG. 3 are four electrolyzers 80, each having 24 apparatuses 14 for permanent water electrolysis, which are of a modular design and can be expanded as required. These electrolyzers 80 for permanent hydrogen and oxygen production interact with the heat exchangers 94 and 96.

[0071] The liquid air energy storage and power plant apparatus 12 includes the charging component 16, the air storage 18, and the discharging component 20 with the water bath evaporation device 62, with the third heat exchanger 64, with the compressed air buffer tank 66, and with the main turbine 76 with the power generator 78. All these components are shown schematically only in order to illustrate the modular design. In addition, the liquid air energy storage and power plant apparatus 12 and the apparatus 14 for permanent hydrogen electrolysis also include all of the features described with reference to FIG. 1.

[0072] An electrolyzer 80, which has an energy demand of 17.5 MW, currently produces 8,160 kg of hydrogen a day. In doing so, it transfers 4 MWh of heat via the heat exchangers 94, 96 to the water bath evaporation device 62 via the first fluid circuit 98 via the fluid flowing in the first heat line 68.

[0073] The water bath evaporation apparatus 62 includes, for example, 400 m3 of water bath, which requires 18.6 MWh to be heated from 10° C. to 50° C. Via the pump 58 and the associated air-heated water bath evaporation device 62, 40 m3/h of liquid air is introduced into the water bath evaporation device 62, while 28,000 Nm3/h of compressed air is supplied from the water bath evaporation device 62 to the third heat exchanger 64. Here the temperature difference between the liquid air introduced and the discharged compressed air is 100° C. and thus corresponds to an energy input via the water bath evaporation device of approx. 9.5 MWh.

[0074] The volume of the liquid air storage 18 is 1,200 m3, for example, which corresponds to approximately 165 MWh of stored energy. Approx. 20 MW of energy is supplied to the compressor 26 by the motor 24 for compressing the intake air. Heat energy is released through the second heat exchanger 32, which heat energy is delivered to the water bath evaporation device 62 through the second fluid circuit 38 via the fluid flowing in the second heat line 36.

[0075] During operation of the liquid air energy storage and power plant apparatus 12, the turbine 76 with connected generator 48 can be used to generate energy which is then supplied to the power grid 22.

[0076] Because of the diverse portfolio of compressors, gearboxes and generators, the detailed specifications only need to be defined or adapted during the planning phase.

LIST OF REFERENCE SIGNS

[0077] 10 system [0078] 12 liquid air energy storage and power plant apparatus [0079] 14 apparatus for permanent water electrolysis [0080] 16 charging component [0081] 18 liquid air storage [0082] 20 discharging component [0083] 22 power grid [0084] 24 electric motor [0085] 26 compressor [0086] 28 air intake filter [0087] 30 air line [0088] 32 second heat exchanger arranged in charging component 16 [0089] 34 dryer [0090] 36 heat line, second heat fine [0091] 38 fluid circuit, second fluid circuit [0092] air liquefier [0093] 42 heat exchanger [0094] 44 regulating valve [0095] 46 expansion turbine [0096] 48 brake generator [0097] 50 expansion valve [0098] 52 expansion tank [0099] 54 electrical control center [0100] 56 additional regulating valve upstream of air storage 18 [0101] 58 pump [0102] 60 motor of pump 58 [0103] 62 water bath evaporation apparatus [0104] 64 third heat exchanger [0105] 66 pressurized air buffer tank [0106] 68 first heat line [0107] 70 bypass line [0108] 72 bypass valve [0109] 74 pneumatic valve [0110] 76 main turbine [0111] 78 power generator [0112] 80 electrolyzer [0113] 86 oxygen storage tank [0114] 88 hydrogen storage tank [0115] 90 fluid circuit—oxygen [0116] 92 fluid circuit—hydrogen [0117] 94 heat exchanger—oxygen [0118] 96 heat exchanger—hydrogen [0119] 98 first fluid circuit [0120] 100 bypass line [0121] 102 bypass valve [0122] 104 equalizing line [0123] 106 equalizing valve