Apparatus for providing hydrogen

Abstract

To provide an apparatus for providing hydrogen (H2) by means of an electrolysis unit (2), which enables as long as possible the service life of the electrolysis unit (2) even in the event of fluctuations in the energy supply to the electrolysis unit (2), a reciprocating piston compressor (3) is provided for compressing hydrogen (H2) produced by the electrolysis unit (2), wherein the reciprocating piston compressor (3) has at least one automatic suction valve (5), wherein a sucking back gripper (6) is provided for selectively holding the suction valve (5) in an open position, wherein an electrically drivable actuator (7) is provided for operating the sucking back gripper (6), wherein a control unit (4) is provided for controlling the actuator (7), wherein the control unit (4) is configured to drive and control the actuator (7) such that an output-side pressure (p1) of the hydrogen (H2) at the output side of the electrolysis unit (2) or a differential pressure (Δp) between the anode and cathode of the electrolysis unit (2) can be set to predetermined target values ​​(p1_soll, Δp_soll).

Description

[Technical field]

[0001] The present invention relates to an apparatus for providing hydrogen, the apparatus being provided with an electrolysis unit for producing hydrogen. The present invention further relates to a method for operating such an apparatus.

[0002] Based on the progress of climate change, CO 2 Political regulations regarding permissible emissions are becoming increasingly strict. Therefore, especially in transport, efforts are being made to find alternative fuels to known fossil fuels (diesel, gasoline, natural gas, etc.). One possible approach is, for example, the use of battery-powered vehicles with an electric drive. Here, pre-generated electrical energy is stored in a battery and used to drive an electric motor. However, here, CO 2 The extent of the reduction also depends heavily on the type of electricity generation and the energy used to manufacture the batteries. However, for the moment, purely battery-electric operation is still not economically feasible, especially for commercial vehicles, due essentially to the poor ratio between weight or structural size and storage capacity. Suitable batteries may therefore be too large and / or too heavy, which may unacceptably limit transport capabilities.

[0003] A further possibility is the use of hydrogen to drive the vehicle. Here, hydrogen can be used, for example, as fuel in a modified internal combustion engine or can be converted into electrical energy in a fuel cell and used to drive an electric motor. Hydrogen can, for example, be stored in liquid form in suitable cryogenic tanks or in gaseous form in pressure vessels under sufficiently high pressure. This already makes it possible to achieve long driving ranges similar to those of conventional drives even in commercial vehicles. Electrolysis is known in the prior art for producing hydrogen. Here, electrical energy is used to convert water into hydrogen (H 2 ) and oxygen (O 2) are decomposed into hydrogen and CO. Various construction types of electrolysis units, so-called electrolysers, are known here, which differ in their construction. At the output side of the electrolysis unit, hydrogen is provided at a defined pressure (independent of the construction type). Thus, the CO 2 The reductions will also depend on the type of electricity generation used to supply the electrolysis units.

[0004] It is therefore particularly advantageous to use renewable energy carriers, for example wind or photovoltaic power, for the energy supply of the electrolysis units. In contrast to conventional, in particular fossil-based, energy carriers, the power generation here does not usually always take place at a constant level, but is strongly dependent on the prevailing ambient conditions. In the case of wind power systems, the power generation is of course not constant, since it varies with the wind power. In the case of photovoltaic power systems, the power generation varies with the amount of solar radiation, which is also usually not constant, for example due to clouds or shading. Thus, if the electrolysis units are directly connected to the respective energy source, the electrical energy supply of the electrolysis units also varies depending on the fluctuations in the power generation of the energy source. However, a fluctuating power supply to the electrolysis units is undesirable, since this leads to pressure fluctuations in the hydrogen generated at the output of the electrolysis units. These pressure fluctuations also have a negative effect on the durability and thus on the lifespan of the electrolysis units.

[0005] It is therefore an object of the present invention to provide an apparatus for providing hydrogen by means of an electrolysis unit, which enables the longest possible service life of the electrolysis unit also in the event of fluctuations in the energy supply to the electrolysis unit.

[0006] This object is achieved in an apparatus as mentioned at the beginning, in which a reciprocating piston compressor for compressing hydrogen produced by an electrolysis unit is provided, the reciprocating piston compressor having at least one automatic intake valve, a suck-back gripper is provided for selectively holding the intake valve in an open position, an electrically controllable actuator for operating the suck-back gripper is provided, and a control unit is provided for controlling the actuator, the control unit being configured to control the actuator in such a way that the output pressure of hydrogen at the output of the electrolysis unit or the differential pressure between the anode and the cathode of the electrolysis unit can be set to a predefined setpoint value. If the electrolysis unit has a proton exchange membrane between the anode and the cathode, the differential pressure can be the differential pressure at the proton exchange membrane. This allows, for example, for the output pressure to be set to the desired setpoint value relatively quickly via control of the suck-back gripper, even in the event of fluctuations in the energy supply of the electrolysis unit, which up to now have been linked to fluctuations in the output pressure.

[0007] As the setpoint value, for example, a fixed numerical value can be assumed or at least one further characteristic value, preferably a function for determining the setpoint value as a function of time, can be stored in the control unit. This makes it possible to set a constant output pressure or differential pressure, independent of the possibly fluctuating energy supply. Alternatively, it is also possible to set a specific time course of the output pressure or differential pressure. This can be advantageously assumed, for example, when the electrolysis unit is switched off or when the energy supply is interrupted, so that the output pressure is reduced to a specific pressure in a comparatively slow and controlled manner.

[0008] A specific unit is preferably provided for determining an actual value of the output pressure or the differential pressure, the control unit being configured to use the determined actual value for closed-loop control of the output pressure or the differential pressure to a preset setpoint value. The calculation unit preferably has at least one sensor and / or a calculation model, where the calculation model is preferably stored in the control unit. As a sensor, for example, a pressure sensor may be provided for capturing the actual value of the output pressure of hydrogen at the output of the electrolysis unit. The pressure sensor may here be arranged in a connecting line connecting the output of the electrolysis unit to the piston compressor. A differential pressure sensor may be provided for capturing the actual value of the differential pressure.

[0009] The control unit is preferably configured to determine a manipulated variable for the actuator from the determined actual value and the set target value and to control the actuator using the determined manipulated variable. For this purpose, it is advantageous if the control unit has a suitable controller, for example a PI or PID controller, for determining the manipulated variable. This allows a closed-loop control circuit to be realized, by which the output pressure or the differential pressure can be set very accurately.

[0010] Additionally or alternatively, the control unit may be configured to store a function for determining the manipulated variable for the actuator as a function of a preset setpoint, and to determine the manipulated variable for the actuator from this function and to control the actuator using the determined manipulated variable. This allows a (feedforward) open-loop control, which is simpler than a (feedback) closed-loop control. The function here can be considered as known or, if appropriate, can be determined from trials.

[0011] Preferably, an electrical energy source is provided for the energy supply of the electrolysis unit and / or the reciprocating piston compressor. This may envisage, for example, an energy supply of the entire device by a single energy source. Particularly preferably, the energy source comprises a renewable energy generator connected to the electrolysis unit and / or the reciprocating piston compressor, where the energy generator preferably comprises a photovoltaic or wind power system. This allows the use of renewable energy carriers for the production of hydrogen, which is advantageous for environmental reasons. Since renewable energy generators generate energy that is usually not constant in time depending on the environmental conditions, the control or closed-loop control of the output pressure or differential pressure according to the invention is particularly advantageous, since this allows, for example, fluctuations to be quickly and simply compensated for.

[0012] The actuator is preferably configured as a pneumatic, hydraulic or electromagnetic actuator, with electromagnetic actuators being particularly advantageous due to their short response times in order to be able to react as quickly as possible to fast pressure fluctuations.

[0013] It is advantageous if the at least one automatic intake valve is configured as an annular valve, which preferably has a number of annular valve openings and a number of annular valve elements that can be manipulated by the suck-back gripper, which embodiment has already been demonstrated in previous compressors.

[0014] The reciprocating piston compressor may preferably be configured as a double-acting reciprocating piston compressor and / or as a multi-stage reciprocating piston compressor. By selecting a suitable embodiment of the reciprocating piston compressor, the device can be flexibly adapted to different basic conditions.

[0015] The electrolysis unit can be supplied with time-variant electrical energy, e.g. directly from a renewable energy generator, and the control unit can control the output pressure or the differential pressure in a closed loop to a preset, e.g. constant, setpoint value.

[0016] If the electrolysis unit is deactivated or the electrical energy supply of the electrolysis unit is interrupted, the control unit can also reduce the output-side pressure, for example to a determined value according to a preset time function, so that the output-side pressure can, for example, be reduced slowly, which is advantageous for the fatigue strength of the electrolysis unit.

[0017] In the following, the invention at issue will be explained in more detail with reference to Figure 1, which shows, exemplarily, diagrammatically and in a non-limiting manner, an advantageous embodiment of the invention. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 illustrates an apparatus for providing hydrogen in an exemplary embodiment of the invention.

[0019] The apparatus 1 shown in FIG. 2 and an electrolysis unit 2 for generating hydrogen H generated by the electrolysis unit 2. 2and a reciprocating piston compressor 3 for compressing the electrolytic solution. Furthermore, a control unit 4 is provided for controlling the device 1. This control unit 4 has suitable hardware and / or software. Such control units 4 are known in the prior art and therefore will not be described in detail here. In FIG. 1, the control unit 4 is exemplarily configured to control the electrolytic unit 2 and the piston compressor 3. However, this is to be understood as merely exemplary, and as shown in FIG. 1, a separate electrolytic control unit 4a for the electrolytic unit 2 and a separate compressor control unit 4b for the piston compressor 3 can also be provided. These control units 4a, 4b can in this case communicate with each other in an appropriate manner for the exchange of a number of sensor signals and / or control signals, which are explained in more detail below. However, it will basically be sufficient within the scope of the present invention if only a compressor control unit 4b for controlling the piston compressor 3 is to be provided. This essentially depends on the choice of the operating quantities of the electrolytic unit 2 to be set, which is explained in more detail below.

[0020] In the illustrated example, an electric energy source 13 is provided for the energy supply of the electrolysis unit 2 and the reciprocating piston compressor 3. This energy source 13 exemplarily comprises here a renewable energy generator 13a connected to a drive unit AE of the electrolysis unit 2 and the reciprocating piston compressor 3. In an advantageous embodiment, the energy generator 13a comprises a photovoltaic power system, for example as shown in Fig. 1. Alternatively or additionally, the energy generator 13a may comprise a wind power system (not shown) or another suitable renewable energy generator 13a.

[0021] The structure and function of the reciprocating piston compressor 3 are sufficiently known, therefore the reciprocating piston compressor 3 is only shown diagrammatically in Fig. 1. In the known form, the reciprocating piston compressor 3 has several cylinders Z in which a piston K can reciprocate with a stroke movement H between top dead center and bottom dead center. Although Fig. 1 shows only one cylinder Z by way of example, the reciprocating piston compressor 3 can of course have several cylinders Z. The pistons K are driven via piston rods KS, which are connected to a crosshead KK in the illustrated example.

[0022] The crosshead KK is also connected on one side to a crank gear (shown diagrammatically). The crank gear has a crankshaft KW, and each piston K has a connecting rod P. The crankshaft KW is driven by a suitable drive AE, for example an electric machine. The drive AE is supplied with electrical energy here from the same energy source 13 as the electrolysis unit 2. Of course, it would also be possible to supply the drive AE of the piston compressor 3 with drive energy from a separate energy source. The crosshead KK is connected to the crankshaft KW via the connecting rod P and is driven by this crankshaft KW. The crosshead bears the transverse forces generated by the connecting rod P in the housing of the reciprocating compressor 3, so that the piston rod KS performs a substantially pure reciprocating movement that is as free as possible from transverse forces. However, the piston compressor 3 can also basically be formed without a crosshead KK, in which case the drive of the piston K takes place directly via the connecting rod P in this case.

[0023] In the cylinder Z, a compression chamber KR is provided, which is bounded on the one hand by the movable piston K and on the other hand by the wall of the piston compressor 3, for example the cylinder head ZK. At least one intake valve 5 and at least one pressure valve 8 for gas exchange are provided in the region of the compression chamber KR. However, differently from the arrangement shown, it is of course also possible to provide several intake valves 5 and / or several pressure valves 8. A radial arrangement in the cylinder Z would also of course be possible. During the expansion stroke of the piston K, the compressed medium, here hydrogen H 2 produced by the electrolysis unit 2, is introduced into the compression chamber KR. 2 is sucked in by the open intake valve 5 and flows into the compression chamber KR. During the subsequent compression stroke of the piston K, the compressed medium is compressed. When a determined pressure is reached, the pressure valve 8 is opened and the compressed medium can flow through the open pressure valve 8. The compressed compressed medium can then be fed, for example, to a suitable accumulator (not shown) or can be fed to a load (not shown), for example a fuel cell.

[0024] The reciprocating piston compressor 3 has at least one automatic suction valve 5, which opens automatically depending on the pressure state during the expansion stroke of the piston K and closes automatically during the compression stroke of the piston K. Thereby, no external energy is required for valve operation, for example by means of an actuator. Furthermore, a suck-back gripper 6 is provided, by means of which the suction valve 5 can be selectively held in an open position, independent of the existing pressure situation. The suction valve 5 is preferably configured as an annular valve, which in this case preferably has a plurality of annular valve openings 5a and a plurality of annular valve elements 5b, which in the closed state of the annular valve 5 seal the valve opening 5a. The suck-back gripper 6 in this case preferably has a plurality of suck-back gripper fingers, which can penetrate the valve opening 5a and operate the valve element 5b. Annular valves according to the same concept are known in the prior art and therefore will not be described in any more detail here.

[0025] Furthermore, an electrically controllable actuator 7 is provided for operating the suck-back gripper 6. This actuator 7 can be configured, for example, as a pneumatic, hydraulic or electromagnetic actuator, with electromagnetic operation being preferred due to the short switching times. The pressure valve 8 is only shown diagrammatically in FIG. 1 and can also be configured, for example, as an automatic valve, like the intake valve 5. The valve element would in this case open opposite the compression chamber KR at a certain pressure ratio. However, as an alternative, a suitable valve other than the pressure valve 8 can of course also be provided, for example a non-automatic valve which can be operated by a suitable actuator.

[0026] The reciprocating piston compressor 3 can be designed differently from the illustrated embodiment, for example as a double-acting reciprocating piston compressor. Here, in the cylinder Z, a first compression chamber KR is provided on the side of the piston K facing away from the crank gear (as shown in FIG. 1) and additionally, a second (not shown) compression chamber KR is provided on the side of the piston K facing the crank gear. This second compression chamber KR is of course also provided with at least one intake valve and a pressure valve for gas exchange.

[0027] The reciprocating piston compressor 3 may of course also be configured as a multi-stage compressor. In this case, several cylinders Z are provided in compression chambers KR with different compression ratios. The pressure valve of a first compression chamber would then be connected to the intake valve of the following second compression chamber. The compressed medium, here hydrogen H 2must be compressed in several stages to the desired final pressure. Both double-acting reciprocating piston compressors and multi-stage compressors are known in the prior art. Of course, a combination of a double-acting reciprocating compressor and a multi-stage compressor is also conceivable. In this case, it is advantageous if at least the first compressor stage at the output of the electrolysis unit 2 has an automatic suction valve 5 with a suck-back gripper and an actuator 7.

[0028] The control unit 4 (or the compressor control unit 4b) controls the amount of hydrogen H 2 The control unit 4 is configured to drive the actuator 7 such that the output pressure p1 of the electrolysis unit 2 or the differential pressure Δp between the anode and cathode of the electrolysis unit 2 can be set to a preset target value. If the electrolysis unit 2 comprises a PEM electrolyser 2a with a proton exchange membrane between the anode and the cathode, the differential pressure Δp is preferably the differential pressure Δp at the proton exchange membrane 11. The reciprocating piston compressor 3 preferably operates at a defined constant rotation speed during operation of the apparatus 1. To this end, the control unit 4 (or the compressor control unit 4b) can correspondingly drive the drive unit AE of the reciprocating piston compressor 3.

[0029] Preferably, a target value for the operating quantity, e.g. hydrogen H 2 A target pressure p1_soll for the pressure difference Δp at the exchange membrane 11 or a target pressure difference Δp_soll for the differential pressure Δp at the exchange membrane 11 is preset. The control unit 4 can use the preset target values ​​for controlling the actuator 7 or for the closed-loop control. This allows, for example, the sucking back gripper 6 to suck back the hydrogen H 2It is possible to set a constant output pressure p1 or a constant pressure difference Δp across the exchange membrane 11. This can ensure that the output pressure p1 or the pressure difference Δp remains constant also in case of a fluctuating energy supply by the energy source 13, e.g. a photovoltaic system 13a. In the normal case, a fluctuating energy supply can lead to pressure fluctuations in the output pressure p1, which, as mentioned at the beginning, has a negative effect on the durability of the electrolysis unit 2 and in particular the exchange membrane 11.

[0030] The setpoint value may for example be a fixed numerical value, for example a setpoint output pressure p1_soll in the range 15 bar to 40 bar or a preset setpoint differential pressure Δp_Soll. In the case of full load of the electrolysis unit 2, the setpoint output pressure p1_soll may for example be in the range 30 bar. In the case of partial load, the setpoint output pressure p1_soll may for example be in the range 25 bar. Furthermore, it may also be advantageous to keep the output pressure p1 at a fixed value after the electrolysis unit 2 has been deactivated. This may be advantageous for a fast restart of the electrolysis unit 2.

[0031] The control unit 4 may also store at least one further characteristic variable, e.g. a function for determining a setpoint value as a function of time, so that, for example, upon deactivation of the electrolysis unit 2, the output pressure p1 can be reduced in a controlled manner from a first value to a second, lower value based on a time function, e.g. in the form of a ramp. This makes it possible to prevent a sudden pressure drop at the output of the electrolysis unit 2 after switching off the electrolysis unit 2, which could possibly have a negative effect on the service life of the electrolysis unit 2.

[0032] To achieve a (feedback) closed-loop control, a calculation unit is preferably provided for determining an actual value p1_ist of the output pressure p1 or an actual value Δp_ist of the differential pressure Δp. The control unit 4 is in this case preferably configured to use the determined actual value for closed-loop control of the output pressure p1 or the differential pressure Δp to a preset setpoint value.

[0033] The calculation unit may have at least one sensor and / or a calculation model, which is preferably stored in the control unit 4. As shown in Fig. 1, for example a pressure sensor 10a may be provided for capturing an actual value p1_ist of the output pressure p1 of the electrolysis unit 2. This pressure sensor 10a may for example be provided directly at the output of the electrolysis unit 2 and / or may be part of the electrolysis unit 2. The pressure signal captured by the pressure sensor 10a may then be transmitted to the control unit 4 and processed by the control unit 4 for the closed-loop control of the actuator 7.

[0034] If a separate electrolysis control unit 4a and a separate compressor control unit 4b are provided, the sensor signal of the pressure sensor 10a could, for example, also be transmitted to the electrolysis control unit 4a and from there to the compressor control unit 4b. It would of course also be possible to transmit the sensor signal directly to the compressor control unit 4b. This last variant is particularly advantageous if an existing electrolysis unit 2 is retrofitted with a compressor 3 for pressure control, since in this case access to the electrolysis control unit 4a is possibly not possible.

[0035] As shown in FIG. 1, the output side of the electrolysis unit 2 may be connected to a piston compressor 3, in particular to the suction line of the piston compressor 3, via a connecting line L. The hydrogen H 2can be supplied to at least one automatic intake valve 5 of the piston compressor 3 via a connecting line L. The pressure sensor 10a can therefore be arranged, for example, in the connecting line L. Optionally, a further device 12, for example a filter, can also be arranged between the output of the electrolysis unit 2 and the input of the piston compressor 3, as shown by dashed lines in FIG. 1. The pressure sensor 10a can in this case be arranged upstream or downstream of the filter 12 in the flow direction. In general, the output pressure p1 is to be understood within the context of the present invention as meaning the pressure at any point in the connecting line L between the output of the electrolysis unit 2 and the input of the piston compressor 3.

[0036] Alternatively or additionally to the pressure sensor 10a, it may also be advantageous if a differential pressure sensor 10b is provided for capturing the actual value Δp_ist of the differential pressure Δp at the exchange membrane 11. This allows not only a closed-loop control of the output pressure p1 but also a closed-loop control of, for example, a constant differential pressure Δp at the exchange membrane 11. This is advantageous, since the exchange membrane 11 of the electrolyzer 2a is relatively sensitive to excessively large pressure differences between the anode side and the cathode side. As the differential pressure sensor 10b, a suitable sensor can be used or even two pressure sensors can be used, from the difference of which the differential pressure Δp of interest is determined, for example, by the control unit 4.

[0037] Alternatively or additionally to any sensor, the calculation unit could also have a calculation model for determining the actual value. This calculation model could, for example, be stored in the control unit 4 in the form of a mathematical function, a characteristic curve or a characteristic map. The calculation model could be known and could, for example, be predefined by the manufacturer of the electrolysis unit 2. Alternatively, it could also be determined empirically, for example by trials. Via the calculation model, the actual value of the output pressure p1_ist or the actual value Δp_ist of the differential pressure Δp can be calculated from further available characteristic quantities. For example, the amount of hydrogen H at the output of the electrolysis unit 2 can be calculated from the actual value Δp_ist of the output pressure p1_ist or the actual value Δp_ist of the differential pressure Δp. 2 It would be conceivable to determine the output pressure p1 from electrical measured quantities, for example the current, the current voltage or the current power of the electrolysis unit 2. These electrical measured quantities can here be captured relatively simply by means of suitable measuring devices.

[0038] A measuring device for acquiring electrical measured quantities (current, voltage, power) could for example be integrated in the electrolysis unit 2 as an integral component of the electrolysis unit 2. These measured quantities could in this case be transmitted to a control unit 4 (for example an electrolysis control unit 4a) and used by said control unit 4 as input quantities for a calculation model. As output quantity, the control unit 4 could for example determine the actual value p1_ist of the output pressure p1 at the output of the electrolysis unit 2.

[0039] Alternatively, however, a separate measuring device (not shown) can be provided for capturing electrical measured quantities (current, voltage, power) which are not part of the electrolysis unit 2. This separate measuring device can, for example, be arranged in a supply line which supplies the electrolysis unit 2 with electrical energy from the energy source 13. The measured quantities captured by this separate measuring device could likewise be transmitted to the control unit 4 (in this case, for example, the compressor control unit 4b) and used by the control unit 4 as input quantities for the calculation model. This variant with a separate measuring device can also be used in an advantageous manner for retrofitting existing electrolysis units 2.

[0040] The control unit 4 determines a suitable control variable S1 for the actuator 7 from the determined actual value (e.g. actual value p1_ist of the output pressure p1 or actual value Δp_ist of the differential pressure Δp) and a preset setpoint value (e.g. a constant setpoint p1_soll of the output pressure p1 or a constant setpoint Δpsoll of the differential pressure Δp) and can control the actuator 7 using the determined control variable S1. To determine the control variable S1, a suitable controller, for example a PI controller or a PID controller, is preferably provided in the control unit 4. The type of the control variable S1 depends on the concrete configuration of the actuator 7 and can be, for example, a current or a voltage. The actuator 7 then adjusts the suck-back gripper 6, preferably steplessly, to actuate the suction valve 5 as a function of the control variable S1 for closed-loop control of the output pressure p1 or the differential pressure Δp.

[0041] In principle, however, a (feedback) closed-loop control does not have to be assumed, but a (feedforward) control could also be used. For this purpose, the control unit 4 can store, for example, a function of the manipulated variable S1 as a function of a preset setpoint (for example as a function of the setpoint p1_soll of the output pressure p1 or of the setpoint Δp of the differential pressure Δp) in order to determine the manipulated variable S1 for the actuator 7. The control unit 4 can then determine the manipulated variable S1 for the actuator 7 on the basis of the setpoint from the function and control the actuator 7 with the determined manipulated variable S1. The function can, for example, also be stored in the control unit 4 as a mathematical function, as a characteristic curve or a characteristic map. This function can be known or a suitable function can be determined, for example, by trial and error.

[0042] The electrolysis unit 2 can for example be supplied with time-variant electrical energy directly from the renewable energy generator 13a, i.e. without any electrical load or electrical storage arranged therebetween. The control unit 4 can hereby perform closed-loop control of the output pressure p1 or the differential pressure Δp to a preset, for example constant, setpoint value, as described above. If the electrolysis unit 2 is deactivated or the electrical energy supply of the electrolysis unit 2 is interrupted, the control unit 4 can also reduce the output pressure p1, for example according to a preset time function, to a determined value. This allows the output pressure p1 to be reduced in a controlled manner in the event of a shut-down of the electrolysis unit 2 from a full load pressure of, for example, about 30 bar to a determined lower pressure within a preset time. If a shut-down of the electrolysis unit 2 only takes place temporarily, the output pressure p1 could also be held at a relatively high value, for example in the range of the output pressure p1 before the shut-down, by a corresponding control of the actuator 7.

Claims

1. Hydrogen (H ２ ) is provided with an electrolysis unit (2) for producing hydrogen (H ２ ) , wherein the apparatus (1) for providing The hydrogen (H ２ a reciprocating piston compressor (3) for compressing the The reciprocating piston compressor (3) has at least one automatic intake valve (5), A suck-back gripper (6) is provided for selectively holding the suck-back valve (5) in an open position; an electrically controllable actuator (7) for operating the suck-back gripper (6); a control unit (4) for controlling the actuator (7); The control unit (4) controls the hydrogen (H ２ the actuator (7) is configured to drive and control the output pressure (p1) of the electrolysis unit (2) or the differential pressure (Δp) between the anode and cathode of the electrolysis unit (2) can be set to predetermined target values ​​(p1_soll, Δp_soll).

2. 2. The apparatus (1) according to claim 1, wherein the electrolysis unit (2) comprises a proton exchange membrane (11) between the anode and the cathode, and the differential pressure (Δp) is the differential pressure (Δp) across the proton exchange membrane (11).

3. 2. The device (1) according to claim 1, wherein the setpoint values ​​(p1_soll, Δp_soll) are determined numerical values ​​or the control unit (4) stores a function for determining the setpoint values ​​(p1_soll, Δp_soll) as a function of at least one further characteristic, preferably as a function of time.

4. 2. The device (1) according to claim 1, further comprising a calculation unit for determining actual values ​​(p1_ist, Δp_ist) of the output pressure (p1) or the differential pressure (Δp), and the control unit (4) is configured to use the determined actual values ​​(p1_ist, Δp_ist) for closed-loop control of the output pressure (p1) or the differential pressure (Δp) to the preset setpoint values ​​(p1_soll, Δp_soll).

5. 5. The device (1) according to claim 4, wherein the calculation unit comprises at least one sensor (10a, 10b) and / or the calculation unit comprises a calculation model, the calculation model being preferably stored in the control unit (4).

6. 5. The device (1) according to claim 4, wherein the at least one sensor comprises a pressure sensor (10a) for capturing an actual value (p1_ist) of an output pressure (p1) of hydrogen (H2) at the output side of the electrolysis unit (2), the pressure sensor (10a) being preferably arranged in a connecting line (L) connecting the output side of the electrolysis unit (2) to the piston compressor (3), and / or the at least one sensor comprises a differential pressure sensor (10b) for capturing an actual value (Δp_ist) of the differential pressure (Δp).

7. 5. The device according to claim 4, wherein the control unit (4) is configured to determine a manipulated variable (S1) for the actuator (7) from the determined actual values ​​(p1_ist, Δp_ist) and the preset setpoint values ​​(p1_soll, Δp_soll) and to drive and control the actuator (7) using the determined manipulated variable (S1), and the control unit (4) preferably has a controller, for example a PI controller or a PID controller, for determining the manipulated variable (S1).

8. 2. The device (1) according to claim 1, wherein the control unit (4) stores a function for determining an operating variable (S1) depending on the preset setpoint values ​​(p1_soll, Δp_soll), and the control unit (4) is configured to determine an operating variable (S1) for the actuator (7) from the function and to drive and control the actuator (7) using the determined operating variable (S1).

9. 2. The device (1) according to claim 1, further comprising an electrical energy source (13) for the energy supply of the electrolysis unit (2) and / or the reciprocating piston compressor (3).

10. 10. The apparatus (1) according to claim 9, wherein the energy source (13) comprises a renewable energy generator (13a) connected to the electrolysis unit (2) and / or the reciprocating piston compressor (3), the energy generator (13a) preferably comprising a photovoltaic power system or a wind power system.

11. 2. The device (1) according to claim 1, wherein the actuator (7) is configured as a pneumatic, hydraulic or electromagnetic actuator.

12. 2. The device (1) according to claim 1, wherein the at least one automatic suction valve (5) is configured as an annular valve, which preferably has a plurality of annular valve openings and a plurality of annular valve elements operable by the suction gripper (6).

13. 2. The device (1) according to claim 1, wherein the reciprocating piston compressor (3) is configured as a double-acting reciprocating piston compressor and / or a multi-stage reciprocating piston compressor.

14. A method for operating a device (1) according to any one of claims 1 to 13, comprising: Hydrogen (H ２ ) and The generated hydrogen (H ２ ) is supplied to a reciprocating piston compressor (3) through at least one intake valve (5) and compressed by said reciprocating piston compressor (3); A target value (p1_soll, Δp_soll) for the output side pressure (p1) or the differential pressure (Δp) is preset, A method according to claim 1, characterized in that the control unit (4) drives and controls the actuators (7) to set the setpoint values ​​(p1_soll, Δp_soll).

15. 15. The method according to claim 14, wherein a defined numerical value is used as the setpoint value (p1_soll, Δp_soll) or the setpoint value (p1_soll, Δp_soll) is determined from at least one further characteristic variable, preferably a time-dependent function.

16. 15. The method according to claim 14, wherein an actual value (p1_ist) of the output pressure (p1) or the differential pressure (Δp) is determined during operation of the device (1), and the control unit (4) determines a manipulated variable (S1) for the actuator (7) from the actual value (p1_ist) and the setpoint value, and controls the actuator (7) using the determined manipulated variable (S1), the manipulated variable (S1) being determined by a controller, preferably a PI controller or a PID controller.

17. 15. The method according to claim 14, wherein a manipulated variable (S1) for the actuator (7) is determined from a function of the manipulated variable (S1) as a function of the preset setpoint values ​​(p1_soll, Δp_soll), and the control unit (4) controls the actuator (7) using the determined manipulated variable (S1).

18. 15. The method according to claim 14, wherein the electrolysis unit (2) is supplied with time-varying electrical energy directly from a renewable energy generator (13a), and the control unit (4) controls the output pressure (p1) or the differential pressure (Δp) in a closed loop to predetermined setpoint values ​​(p1_soll, Δp_soll).

19. 15. The method according to claim 14, wherein the electrolysis unit (2) is deactivated or the electrical energy supply of the electrolysis unit (2) is interrupted and the control unit (4) reduces the output pressure (p1) to a determined value according to a preset time function.

20. 15. The method according to claim 14, wherein the reciprocating piston compressor (3) is operated at a defined constant rotational speed.

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