Hydrogen storage power plant, and method for operating same

Abstract

The invention relates to a hydrogen storage power plant (1) comprising: in order to produce hydrogen (H.sub.2) from methane or natural gas, a pyrolysis device for methane pyrolysis and/or natural gas pyrolysis and/or a plasmalysis device (6) for methane plasmalysis and/or natural gas plasmalysis; -a storage device (11), which is coupled on the output side to the pyrolysis device, for storing the hydrogen (H.sub.2) or a storage device (11), which is coupled on the output side to the plasmalysis device (6), for storing the hydrogen (H.sub.2); and a hydrogen combustion engine (12) which is coupled on the outlet side to the storage device (11) and has a closed noble gas circuit (12.1) for circulating noble gas, which noble gas circuit leads from an outlet channel (12.2) of the hydrogen combustion engine (12) via a circulation path to an inlet channel (12.3) of the hydrogen combustion engine (12) and guides a noble gas (EG) from the outlet channel (12.2) via the inlet channel (12.3) into a combustion chamber of the hydrogen combustion engine (12). The invention also relates to a method for operating such a hydrogen storage power plant (1).

Claims

1. A hydrogen storage power plant, comprising: at least one of a pyrolysis device and a plasmalysis device, for producing hydrogen from methane or natural gas; a storage device for storing the hydrogen, coupled on an output side to the pyrolysis device or coupled on an output side to the plasmalysis device; a hydrogen combustion engine coupled on the output side to the storage with a closed noble gas cycle for noble gas circulation, which leads from an exhaust port of the hydrogen combustion engine via a circulation path to an inlet port of the hydrogen combustion engine and guides a noble gas from the exhaust port via the inlet port into a combustion chamber of the hydrogen combustion engine; and having at least one of a plasmalysis waste heat extraction point for extracting waste heat arising during methane plasmalysis and/or natural gas plasmalysis, a cooling circuit waste heat extraction point for extracting waste heat from a cooling circuit, which is generated during the combustion of hydrogen and transferred to a cooling circuit of the hydrogen combustion engine, and an exhaust gas waste heat extraction point for extracting waste heat generated during the combustion of hydrogen and transferred to an exhaust gas of the hydrogen combustion engine from the exhaust gas; wherein a switch is coupled to the plasmalysis waste heat extraction point, the exhaust gas waste heat extraction point and a thermodynamic cycle via a medium, and the switch is designed to couple the plasmalysis waste heat extraction point and the exhaust gas waste heat extraction point separately and together with the thermodynamic cycle via the medium.

2. The hydrogen storage plant according to claim 1, wherein the noble gas is argon.

3. The hydrogen storage plant according to claim 1, comprising an oxygen generation unit whose outlet is coupled to the inlet port of the hydrogen combustion engine.

4. The hydrogen storage plant according to claim 3, wherein the oxygen generation unit is a gas permeation device which is designed to separate a gas mixture, at least into oxygen and nitrogen.

5. The hydrogen storage plant according to claim 4, wherein the gas permeation device is configured for a cascaded separation of the gas mixture and separates nitrogen, oxygen and argon from the gas mixture.

6. The hydrogen storage power plant according to claim 4, wherein the gas mixture is air.

7. The hydrogen storage plant according to claim 1, wherein the pyrolysis device is designed in such a way that methane or natural gas is pyrolyzed without pressure reduction, or the plasmalysis device is designed in such a way that methane or natural gas is pyrolyzed without pressure reduction.

8. The hydrogen storage plant according to claim 1, wherein at least one of the plasmalysis waste heat extraction point and the exhaust gas waste heat extraction point is coupled as a heat source to a thermodynamic cycle, and the thermodynamic cycle is coupled to a generator for the generation of electrical energy.

9. The hydrogen storage plant according to claim 8, wherein the switch is additionally coupled to a heat storage device via the medium, the switch is designed to couple the plasmalysis waste heat extraction point and the exhaust gas waste heat extraction point separately and together with the heat storage device via the medium, and the switch is designed to couple the heat storage device to the thermodynamic cycle via the medium.

10. The hydrogen storage plant according to claim 1, wherein the switch is additionally coupled to a heat storage device via the medium, the switch is designed to couple the plasmalysis waste heat extraction point and the exhaust gas waste heat extraction point separately and together with the heat storage device via the medium, and the switch is designed to couple the heat storage device to the thermodynamic cycle via the medium.

11. A method for operating the hydrogen storage power plant according to claim 1, wherein at least one of a methane pyrolysis and a natural gas pyrolysis and a methane plasmalysis and a natural gas plasmalysis is carried out to produce hydrogen from methane or natural gas, the hydrogen produced is stored, and the stored hydrogen is combusted in the hydrogen combustion engine with the closed noble gas cycle for the noble gas circulation, which leads from the exhaust port of the hydrogen combustion engine via the circulation path to the inlet port of the hydrogen combustion engine and the noble gas is conducted from the exhaust port via the inlet port into the combustion chamber of the hydrogen combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Examples of embodiments of the invention are explained in more detail below with reference to drawings.

(2) FIG. 1 is a schematic diagram of a hydrogen storage power plant,

(3) FIG. 2 schematically shows a gas permeation membrane, and

(4) FIG. 3 schematically shows a cascaded gas permeation membrane.

(5) Corresponding parts are marked with the same reference signs in all figures.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

(6) FIG. 1 shows a circuit diagram of a possible embodiment of a hydrogen storage power plant 1.

(7) The hydrogen storage power plant 1 comprises a voltage converter 2 for converting an electrical voltage of an electrical grid 3 into an operating voltage of the hydrogen storage power plant 1.

(8) A converter 5, via which a plasmalysis device 6 is electrically supplied, can be electrically coupled to the voltage converter 2 via a switch 4.

(9) The plasmalysis device 6 comprises a gas inlet 6.1, via which a gas G, in particular natural gas and/or methane, can be supplied to the plasmalysis device 6. A gas supply can be adjusted by means of a controllable valve 7.

(10) Furthermore, the plasmalysis device 6 comprises a gas outlet 6.2, via which hydrogen H.sub.2 can be discharged, a plasmalysis waste heat extraction point 6.3, for example in the form of a heat exchanger, and an outlet 6.4 for carbon C.

(11) The gas outlet 6.2 is fluidically coupled to a compressor 8, which can be driven by a motor 9. The motor 9 can be electrically coupled to the voltage converter 2 via a further switch 10.

(12) The compressor 8 is fluidically coupled on the output side to a storage device 11 for storing the hydrogen H.sub.2.

(13) The storage device 11 is coupled on the output side to a hydrogen combustion engine 12. The hydrogen combustion engine 12 has a closed noble gas cycle 12.1 for noble gas circulation, with the noble gas cycle 12.1 leading from an exhaust port 12.2 of the hydrogen combustion engine 12 via a circulation path to an inlet port 12.3 of the hydrogen combustion engine 12, and guides a noble gas EG leading from the exhaust port 12.2 via the inlet port 12.3 into a combustion chamber of the hydrogen combustion engine 12.

(14) The hydrogen combustion engine 12 also includes a cooling circuit waste heat extraction point 12.4, an exhaust gas waste heat extraction point 12.5 with a water drain 12.5.1 and a storage tank 12.6 for the noble gas EG, which can be coupled to the noble gas cycle 12.1 via a valve 12.7.

(15) An electric generator 13 is coupled to the hydrogen combustion engine 12 and is driven by the hydrogen combustion engine 12. The generator 13 can be electrically coupled to the voltage converter 2 by means of a further switch 14, so that electrical energy generated by the generator 13 can be fed into the electrical grid 3.

(16) To obtain hydrogen H.sub.2 from natural gas and/or methane, these are or this is supplied to the plasmalysis device 6. In one possible embodiment, the natural gas and/or methane are/is taken directly from a gas network without prior pressure reduction.

(17) In this process, the methane is decomposed in a plasma in the absence of oxygen, according to
CH.sub.4(g)C(f)+2 H.sub.2(g)
to produce hydrogen H.sub.2 and elemental carbon C.

(18) The carbon C is discharged via outlet 6.4 and the hydrogen H.sub.2 is compressed by compressor 8 and stored in storage device 11. If the natural gas and/or methane have been broken down in the plasmalysis without prior pressure reduction, the effort for compressing the hydrogen H.sub.2 may be reduced because of the higher pressure level, since the hydrogen H.sub.2 is already at a higher pressure at the gas outlet 6.2.

(19) In an alternative embodiment not shown here, the hydrogen H.sub.2 can be produced in a methane pyrolysis and/or natural gas pyrolysis by means of a pyrolysis device.

(20) If the stored hydrogen H.sub.2 is to be combusted in the hydrogen combustion engine 12 for reconversion, the hydrogen H.sub.2 is supplied to the hydrogen combustion engine 12 via a valve 15. The noble gas cycle 12.1 is a closed cycle, with argon in particular being used as the noble gas EG.

(21) A combustion of hydrogen H.sub.2 is realized without ambient air. For this purpose, oxygen O2 is supplied to the hydrogen combustion engine 12 via a valve 16.

(22) In one possible embodiment, the hydrogen storage power plant 1 has an oxygen production unit 17 coupled to the valve 16, which is in particular a gas permeation device with a gas permeation membrane 17.1 and a conveying unit 17.2. The conveying unit 17.2 is used to draw air L into the gas permeation membrane 17.1, which separates the air L into nitrogen N.sub.2, oxygen O.sub.2 and the noble gas EG, in particular argon. This means that oxygen O.sub.2 and the noble gas EG can be supplied to the inlet port 12.3 of the hydrogen combustion engine 12, and the storage container 12.6 can be reduced in size or omitted. In particular, to prevent the concentration of noble gas in the noble gas circuit 12.1 from rising above a specified limit, the circuit is regularly purged of excess noble gas EG.

(23) During the combustion of hydrogen with operating gas circulation, water H.sub.2O is formed. This water H.sub.2O is condensed by a condenser, which is, for example, a component of an exhaust gas heat exchanger forming the exhaust gas heat extraction point 12.5, and separated from the noble gas EG used as the working gas, for example argon. As a result, only the noble gas EG is returned to the combustion chamber of the hydrogen combustion engine 1 via the circulation path.

(24) The energy converted into motion in the hydrogen combustion engine 12 by combustion of hydrogen H.sub.2 is transferred to the generator 13, which converts the kinetic energy into electrical energy and feeds it into the electrical grid 3.

(25) In one possible design of the hydrogen storage power plant 1, waste heat generated during plasmalysis in the plasmalysis device 6 and waste heat generated during the combustion of hydrogen H.sub.2 in the hydrogen combustion engine 12 can be utilized in a thermodynamic cycle 18. For this purpose, the plasmalysis waste heat extraction point 6.3 and the exhaust gas waste heat extraction point 12.5 can be coupled as a heat source to the thermodynamic cycle 18. The thermodynamic cycle 18 is designed, for example, as a steam process, an organic Rankine process or a supercritical CO.sub.2 process.

(26) A turbine (not shown in detail) of the cycle 18 is coupled in a known manner to an electric generator 19, which converts kinetic energy of the turbine into electrical energy. This electrical energy is supplied via another switch 20 to an electrical consumer of the hydrogen storage power plant 1 and/or fed into the electrical grid 3.

(27) Since the plasmalysis and combustion processes of hydrogen H.sub.2 take place at different times and generally not simultaneously, the plasmalysis waste heat extraction point 6.3 and the exhaust gas waste heat extraction point 12.5 can be coupled to the cycle 18 in a further possible design via a switching element 21, which, for example, forms a switch. In this case, the switching element 21 is designed in such a way that the coupling with the cycle 18 can be carried out separately and together for the plasmalysis waste heat extraction point 6.3 and the exhaust gas waste heat extraction point 12.5.

(28) In order to be able to operate the cycle 18 even if, at least briefly, no or insufficient waste heat can be provided by plasmalysis and hydrogen combustion, a further possible design envisages that the switching element 21 is additionally coupled to a heat storage device 22 via a medium. Thus, excess waste heat from the plasmalysis and the hydrogen combustion can be stored and supplied to the cycle process 18 as needed, so that it can be operated without interruption.

(29) FIG. 2 shows a possible embodiment of a gas permeation membrane 17.1. The gas permeation membrane 17.1 comprises a housing GE and a plurality of hollow tubes R and is designed to separate air L into two gas groups. One gas group comprises nitrogen N.sub.2 and the other gas group comprises oxygen O2, carbon dioxide CO.sub.2, water H.sub.2O and noble gases EG.

(30) Another possible embodiment of a gas permeation membrane 17.1 is shown in FIG. 3. The gas permeation membrane 17.1 is designed for cascaded gas permeation and has two gas permeation membranes 17.1.1, 17.1.2.

(31) In this process, a first gas permeation membrane 17.1.1, whose function corresponds to the gas permeation membrane 17.1 shown in FIG. 2, is followed by a further gas permeation membrane 17.1.2, which in turn separates the gas group comprising oxygen O.sub.2, carbon dioxide CO.sub.2, water H.sub.2O and noble gases EG into two gas groups. One gas group includes carbon dioxide CO.sub.2 and water H.sub.2O, and another gas group includes oxygen O.sub.2 and the noble gas EG argon. This makes it possible to supply an at least almost pure gas mixture of oxygen O.sub.2 and argon to the hydrogen combustion engine 12.

LIST OF REFERENCES

(32) 1 Hydrogen storage power plant 2 Voltage converter 3 Electrical grid 4 Switch 5 Converter 6 Plasmalysis device 6.1 Gas inlet 6.2 Gas outlet 6.3 Plasmalysis waste heat extraction point 6.4 Outlet 7 Valve 8 Compressor 9 Motor 10 Switch 11 Storage device 12 Hydrogen combustion engine 12.1 Noble gas cycle 12.2 Exhaust port 12.3 Inlet port 12.4 Cooling circuit waste heat extraction point 12.5 Exhaust gas waste heat extraction point 12.5.1 Water drain 12.6 Storage tank 12.7 Valve 13 Generator 14 Switch 15 Valve 16 Valve 17 Oxygen generation unit 17.1 Gas permeation membrane 17.1.1 Gas permeation membrane 17.1.2 Gas permeation membrane 17.2 Conveying unit 18 Cycle 19 Generator 20 Switch 21 Switching element 22 Heat storage device C Carbon CO.sub.2 Carbon dioxide EG Noble gas G Gas GE Housing H.sub.2 Hydrogen H.sub.2O Water L Air N.sub.2 Nitrogen O.sub.2 Oxygen R Tube