EP4339505A1 - Method for filling a container with hydrogen, corresponding device and hydrogen filling station - Google Patents

Abstract

The invention relates to a method for filling a container (152) with hydrogen (M) using an expansion machine (122) which is coupled to an electrical machine (124), the hydrogen (M) being supplied by the expansion machine (122). an inlet (122.1) to an outlet (122.2) of the expansion machine, and wherein a pressure (p2) and / or a volume flow of hydrogen (M) on the side of the outlet are set or regulated to a predetermined value by at least one Operating size of the expansion machine (122) and / or the electrical machine (124) is set or regulated. The invention also relates to a device (120) and a hydrogen filling station (100) for this purpose.

Description

The invention relates to a method for filling a container with hydrogen, a device for providing hydrogen for filling a container, as well as a hydrogen filling station and a use of the device.

Hydrogen, which is used as fuel for vehicles, for example, can be made available via so-called hydrogen filling stations. Two basic system areas can be distinguished at a hydrogen filling station. The first system area concerns the compression of the hydrogen, its storage as well as its conditioning and cooling. The second system area includes a hydrogen dispenser and the associated refueling equipment such as the breakaway and refueling coupling and the refueling hose.

At hydrogen filling stations or other systems or facilities for providing or refilling hydrogen, the hydrogen often has to be expanded from a higher to a lower pressure. However, when valves are typically used for this purpose, the so-called Joule-Thomson effect heats up the hydrogen. Against this background, the task is to improve the provision of hydrogen.

Disclosure of the invention

This object is achieved by a method for filling a container with hydrogen, a device and a hydrogen filling station and a use of the device with the features of the independent patent claims. Preferred embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

The invention is concerned with filling containers or tanks with hydrogen, such as at hydrogen filling stations. When the hydrogen is provided for this purpose, it usually has to be conditioned. Particularly due to the increasing use of hydrogen as fuel, e.g. for fuel cells in vehicles, it is often necessary to decant or fill containers with hydrogen from another container or other source. This not only applies to refueling the tank of a hydrogen-powered vehicle, but also, for example, to filling transport containers on trucks, for example.

Here, the pressure of the hydrogen usually has to be brought from a higher value (at which the hydrogen is stored, for example in a storage tank) to a lower value (which is approved for the vehicle tank, for example), i.e. the hydrogen has to be relaxed; A volume flow may also need to be brought to a different value or adjusted.

One possibility here is to use a pressure control valve, by means of which the pressure of the hydrogen is reduced and set or regulated to a desired value. The relaxation of hydrogen is an isenthal process. However, since hydrogen in particular has a negative Joule-Thomson coefficient, the pressure reduction leads to heating of the hydrogen (heat is removed from the environment, which the hydrogen absorbs) and thus of the pressure control valve and possibly other parts of the device. In particular, it can also happen that the containers or tanks that are filled with the hydrogen are not designed or suitable for such high hydrogen temperatures.

The heat can be dissipated, for example, by using heat exchangers such as plate heat exchangers or indirect heat exchangers with aluminum cold storage; The hydrogen can also be cooled again. However, this entails high costs.

Against this background, the use of an expansion machine (or expansion machine) that is coupled to an electrical machine is now proposed. When filling the container (or tank), the hydrogen, obtained for example from a storage tank or other source, is passed through the expansion machine, from an inlet to an outlet of the expansion machine. After the expansion machine, the hydrogen can then be filled into the container. In this case, a pressure and/or a volume flow of the hydrogen on the outlet side are set or regulated to a predetermined value by setting or regulating at least one operating variable of the expansion machine and/or the electrical machine, for example a power provided as a generator by the electrical machine. The power can, for example, be set or regulated to a specific value. The pressure or the volume flow can in particular be set or regulated dynamically.

The electric machine can therefore be used as a generator and a braking torque is generated or applied by adjusting or regulating the output power. The pressure difference falling across the expansion machine or the volume flow can be changed, in particular dynamically depending on the current requirement. For example, desired profiles such as refueling curves or refueling ramps can be set or regulated, as are often prescribed for refueling vehicles. In particular, it is intended to conduct the hydrogen from the source to the container only via the expansion machine, i.e. not, for example, in parallel via a control valve. The pressure and volume flow are set or regulated solely by the expansion machine.

Unlike a pressure control valve, the expansion machine does not have an isenthalmic process, but rather an isentropic or at least almost or quasi-isentropic process. Enthalpy or energy is removed from the hydrogen and the hydrogen cools despite the negative Joule-Thomson coefficient.

Due to the lack of a pressure control valve where the hydrogen would heat up, the cooling capacity is always maximum. This leads in particular to the fact that the hydrogen does not heat up or only heats up insignificantly and to the fact that not only does no heat have to be dissipated or cooled away, but in fact there is usually even an excess of cold or cold energy.

This can then be used for other purposes, for example to cool one or more components of a hydrogen filling station in which the filling is carried out. The power generated by the electrical machine can also be used in a suitable manner can be used, e.g. fed into a power grid, or can also be used to operate a compressor elsewhere.

This not only means that costs are sometimes significantly reduced, but the ecological footprint is also significantly reduced.

Various variants in particular can be considered as expansion machines. A turbomachine, in particular an axial turbomachine, is preferably used as an expansion machine. Here, the power provided by the electric machine as a generator can be set or regulated as an operating variable in order to set or regulate a pressure difference between a pressure of the hydrogen on the inlet side and on the outlet side, in order to thereby adjust the pressure of the hydrogen on the outlet side or to regulate.

Such a turbomachine (i.e. a turbine) can, for example, be designed or designed in such a way that it delivers almost no pressure difference between the inlet and outlet at maximum speed. The turbomachine then runs freely in the hydrogen stream. If the pressure of the hydrogen is then to be reduced, the brake generator can be switched on electrically by first requiring the power to be delivered by the electric machine. The higher the electrical power required, the higher the braking torque and the higher the pressure difference. This allows an adjustment or regulation of the pressure difference and thus - depending on the pressure on the inlet side - also the pressure on the outlet side. The volume flow can also be adjusted or regulated via the turbomachine.

The electrical machine (or the generator) can, for example, be arranged completely (or only partially) within the turbomachine or turbine. Since there is a zone 0 there, there is no oxidation due to a lack of oxygen concentration and therefore no risk of ignition. The turbine wheel and the rotor of the electric machine can, for example, form a unit and can, for example, be dynamically gas-mounted. An example of a turbine that can be used here is, for example, in the EP 1 273 857 A1 described.

Likewise, a piston engine with a controllable (or controlled) inlet and/or outlet valve is preferably used as an expansion machine. Here you can The working stroke of the piston engine can be set or regulated as an operating variable in order to adjust or regulate the pressure of the hydrogen on the outlet side. Either the inlet valve or the outlet valve or both can be controlled accordingly, so that the effective piston stroke (the working stroke), i.e. the proportion of the mechanical piston stroke with which the hydrogen is expanded, is changed while the piston stroke remains mechanically the same. Opening the inlet valve later, for example, leads to a smaller working stroke, which in turn leads to a lower pressure on the outlet side.

Likewise, for example, a power provided by the electric machine as a generator can be set or regulated as an operating variable in order to set or regulate the volume flow of hydrogen on the outlet side. The braking torque of the electrical machine (or the generator) influences the speed of the electrical machine and thus the piston engine, which in turn has a direct influence on the volume flow.

In order to reduce any pressure surges that may occur, the piston engine can be designed, for example, as a multi-cylinder system (i.e. multi-stage), then in particular with a small displacement (per cylinder).

The use of an ionic expansion machine as an expansion machine is also conceivable. For example, an ionic compressor/expander can be used, which uses the expander or is operated as such.

The invention is shown schematically in the drawing using an exemplary embodiment and is described below with reference to the drawing.

Short description of the drawing

Figure 1

shows schematically a hydrogen filling station according to the invention in a preferred embodiment.

Figure 2

shows schematically a hydrogen filling station according to the invention in a further preferred embodiment.

Detailed description of the drawing

In Figure 1 A hydrogen filling station 100 according to the invention is shown schematically in a preferred embodiment, in which a method according to the invention can also be carried out. The hydrogen filling station 100 has, for example, a storage tank 110, which is intended to serve as a source for hydrogen M. The hydrogen filling station 100 also has, for example, a dispenser 130 on which, for example, refueling equipment for refueling a vehicle 150 can be provided. By way of example, a vehicle tank 152 of the vehicle 150 should be a container that is to be filled with hydrogen M.

The hydrogen M is typically stored in the storage tank 110 at a pressure p1 that is higher than a pressure p2 with which the vehicle tank 152 should or may be filled. A reduction in the pressure between the storage tank 110 and the vehicle tank 152 or even the dispenser 130 is therefore necessary. In particular, it can also be provided that the pressure p2 should not only be set or regulated at a specific value, but so-called refueling curves can also be specified, which require different values for the pressure p2 during the refueling process (i.e. filling the vehicle tank). , which must then be set or regulated accordingly. A specific value for a volume flow of hydrogen M during filling can also be specified, which can also vary, for example, as part of a refueling curve.

For this purpose, the hydrogen filling station 100 now has a device 120 which is intended and set up to provide hydrogen for filling a container, here the vehicle tank 152. The device 120 is a device according to the invention in a preferred embodiment, which in itself could also be used elsewhere than in the hydrogen filling station 110.

The device 120 has an expansion machine 122 and an electrical machine 124 coupled thereto, in particular a generator. By way of example, the expansion machine 122 is a turbomachine, in particular an axial turbomachine, i.e. a turbine. As already mentioned, the turbine and the electrical machine or its rotor can, for example, be designed as a unit.

Likewise, the expansion machine 122 and the electrical machine can be coupled, for example, via a shaft, i.e. connected to one another in a torque-transmitting manner. It should be mentioned that the electrical machine 124 also includes a power converter or inverter.

The turbomachine 122 has an inlet 122.1 for the hydrogen M and an outlet 122.2. The hydrogen M is thus passed through the turbomachine 122, from the inlet 122.1 to the outlet 122.2.

By specifically controlling the electrical machine 124, in particular by adjusting or regulating a power provided by the electrical machine as a generator, the braking effect that the electrical machine exerts on the turbomachine 122 can be specifically adjusted or regulated, which in turn creates a pressure difference p2- p1, i.e. between inlet 122.1 and outlet 122.2, is set or regulated.

For this purpose, for example, the control unit 126 of the device 120 provided as an example can be used. The control unit 126 can also be integrated into the inverter mentioned or vice versa. In this way, the pressure p2 can be brought to desired values during filling or refueling, for example in such a way that a specific refueling curve is achieved. For this purpose, for example, the control unit 126 can also be connected to the dispenser 130 for data transmission, so that the pressure p2 can be regulated accordingly when the refueling process begins.

The power generated by the electrical machine 124 can then, for example, be fed into a power grid, stored in an electrical energy storage device or, for example, used in another way in the hydrogen filling station 100. For example, a compressor (not shown here) can also be operated at another location in the hydrogen filling station.

As mentioned, the expansion of the hydrogen M or the reduction of the pressure by the turbomachine 122 or generally the expansion machine creates cold, and in particular excess cold. This excess cold can be used for cooling in other places, for example in the Hydrogen filling station 100 can be used, for example for cooling the mentioned compressor or for air conditioning in order to be able to maintain any necessary maximum ambient temperatures.

Furthermore, a hydrogen filling station 100 (or the device 120) can have a cold storage 132, in which the cold resulting from the expansion of the hydrogen M is stored or temporarily stored and also smoothed. For this purpose, the hydrogen can be passed through the cold storage (only indicated here). This can be advantageous in that when the pressure difference is high, which typically occurs first, more cold is generated than when the pressure difference is low; Particularly towards the end of the refueling process, there is little to no cold at all.

In Figure 2 A hydrogen filling station 200 according to the invention is shown schematically in a further preferred embodiment, in which a method according to the invention can also be carried out. The hydrogen filling station 200 corresponds to the hydrogen filling station 100 by way of example Figure 1 , with the difference that instead of the device 120, a device 220 is provided, which is intended and set up to provide hydrogen for filling a container, here 220 vehicle tanks 152. The device 120 is a device according to the invention in a preferred embodiment, which in itself could also be used elsewhere than in the hydrogen filling station 110.

Below, only the device 220 and in particular its differences from the device 120 will be discussed. Otherwise, the comments apply Figure 1 accordingly, in particular the same components of the hydrogen filling station 200 are also designated with the same reference numbers as in the hydrogen filling station 100.

The device 200 has an expansion machine 222 and an electrical machine 224 coupled thereto, in particular a generator. By way of example, the expansion machine 222 is a piston machine. The piston engine 222 has, for example, two cylinder units, each of which has an inlet valve 222.1, 222.3 and an outlet valve 222.2, 222.4.

The hydrogen M is thus introduced into the left cylinder unit through the inlet valve 222.1, out through the outlet valve 222.2 and into the right cylinder unit through the inlet valve 222.3. The hydrogen M leaves the right cylinder unit and thus the piston engine through the outlet valve 222.4. The inlet valve 222.1 is therefore an inlet and the outlet valve 222.4 is an outlet of the (entire) piston engine 222. It goes without saying that more cylinder-piston units can also be provided. The cylinder-piston units can be driven by a drive not specified here.

The piston machine or expansion machine 222 and the electrical machine 224 can, for example, be coupled via a shaft, i.e. connected to one another in a torque-transmitting manner. It should be mentioned that the electrical machine 224 also includes a power converter or inverter.

By specifically controlling the electrical machine 224, in particular by adjusting or regulating a power provided by the electrical machine as a generator, the braking effect that the electrical machine exerts on the piston engine 222 can be specifically adjusted or regulated, which in turn increases the speed and thus a volume flow of hydrogen M is set or regulated.

For this purpose, for example, the control unit 226 of the device 220 provided as an example can be used. The control unit 226 can also be integrated into the inverter mentioned or vice versa.

Furthermore, the inlet valves 222.1, 222.3 and the outlet valves 222.2, 222.4 or, for example, only the inlet valves or only the outlet valves can be controlled, i.e. they can be opened and closed in a targeted manner. The control unit 226 can also be used for this, for example. However, a separate control unit can also be provided. This allows the pressure p2 to be set or regulated.

In this way, the working stroke of the piston engine 222 can be changed and the pressure p2 can be brought to desired values during filling or during the refueling process, for example in such a way that a specific refueling curve is achieved becomes. For this purpose, for example, the control unit 226 can also be connected to the dispenser 130 for data transmission, so that the pressure p2 can be regulated accordingly when the refueling process begins.

The power generated by the electrical machine 224 can also, for example, be fed into a power grid, stored in an electrical energy storage device or, for example, used in another way in the hydrogen filling station 200. For example, a compressor (not shown here) can also be operated at another location in the hydrogen filling station.

In the case of the piston engine, too, cold occurs due to the expansion of the hydrogen M or the reduction in pressure, and in particular excess cold. This excess cold can be used, for example, for cooling in other places, for example in the hydrogen filling station 200, for example also for cooling the mentioned compressor.

Furthermore, a hydrogen filling station 200 (or the device 220) can have a cold storage 132, in which the cold resulting from the expansion of the hydrogen M is stored or temporarily stored and also smoothed. For this purpose, the hydrogen can be passed through the cold storage (only indicated here). This can be advantageous in that when the pressure difference is high, which typically occurs first, more cold is generated than when the pressure difference is low; Particularly towards the end of the refueling process, there is little to no cold at all.

Claims (14)

Method for filling a container (152) with hydrogen (M) using an expansion machine (122, 222) coupled to an electrical machine (124, 224), the hydrogen (M) being fed through the expansion machine (122, 222). , from an inlet (122.1, 222.1) to an outlet (122.2, 222.4) of the expansion machine, and
wherein a pressure (p2) and/or a volume flow of hydrogen (M) on the outlet side are set or regulated to a predetermined value by at least one operating variable of the expansion machine (122, 222) and/or the electrical machine (124, 224 ) is set or regulated. Method according to claim 1, wherein a turbomachine, in particular an axial turbomachine, is used as an expansion machine (122). Method according to claim 2, wherein a power provided by the electric machine as a generator is set or regulated as an operating variable in order to set or regulate a pressure difference between a pressure (p1) of the hydrogen on the inlet side and the pressure (p2) on the outlet side, in order to adjust or regulate the pressure (p2) of the hydrogen on the outlet side. Method according to claim 1, wherein a piston engine with a controllable inlet and/or outlet valve is used as an expansion machine (222). Method according to claim 4, wherein a power provided by the electric machine as a generator is set or regulated as an operating variable in order to set or regulate the volume flow of the hydrogen (M) on the outlet side. Method according to claim 4 or 5, wherein a working stroke of the piston engine is set or regulated as an operating variable in order to set or regulate the pressure (p2) of the hydrogen on the outlet side. A method according to claim 1, wherein an ionic expansion machine is used as the expansion machine. A method according to any preceding claim, wherein the hydrogen is obtained from a source (110) and supplied to the container (152) to be filled only through the expansion machine (122, 222). Method according to one of the preceding claims, wherein when filling the container (152), the pressure and/or the volume flow are set or regulated according to a predetermined course, in particular a refueling curve. Device (120, 220) for providing hydrogen (M) for filling a container (152), comprising an expansion machine (122, 222) and an electrical machine (124, 224) coupled thereto, the expansion machine having an inlet (122.1, 222.1) and an outlet (122.2, 222.4) for hydrogen, which are arranged such that the hydrogen can be conducted through the expansion machine (122, 222) from the inlet to the outlet,
wherein the device (120, 220) is set up to set or regulate a pressure (p2) and/or a volume flow of the hydrogen on the outlet side to a predetermined value by at least one operating variable of the expansion machine (122, 222) and/or the electric machine (124, 224) is set or regulated. Device (120, 220) according to claim 10, wherein the expansion machine is designed as a turbomachine, in particular as an axial turbomachine, or as a piston machine with a controllable inlet and / or outlet valve, or as an ionic expansion machine. Hydrogen filling station (100, 200) with a device (120, 220) according to claim 10 or 11. Hydrogen filling station (100, 200) according to claim 12, which is set up to cool one or more components of the hydrogen filling station by means of the cold obtained when the hydrogen (M) is provided. Use of a device (120, 220) according to claim 10 or 11 for refueling a vehicle (150) with hydrogen (M).

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