Apparatus for providing hydrogen

Abstract

The invention relates to a device (1) for supplying hydrogen (H2) by means of an electrolysis unit (2), which enables the service life of the electrolysis unit (2) to be as long as possible even in the event of fluctuations in the energy supply of the electrolysis unit (2), a reciprocating piston compressor (3) is provided for compressing hydrogen (H2) generated by the electrolysis unit (2), the reciprocating piston compressor (3) has at least one automatic suction valve (5), is provided with a lifting gripper (6) for selectively holding the suction valve (5) in an open position, is provided with an electrically actuatable actuator (7) for actuating the lifting gripper (6), and is provided with a control unit (4) for controlling the actuator (7), which control unit (4) is designed to actuate the actuator (7) in such a way that the actuator (7) can be actuated by the lifting gripper (6). In this way, the output pressure (p1) of the hydrogen gas (H2) at the output of the electrolysis unit (2) or the pressure difference (p) between the anode and the cathode of the electrolysis unit (2) can be adjusted to a predetermined setpoint value (p1soll, psoll).

Description

Technical Field

[0001] The invention relates to a device for providing hydrogen, wherein an electrolysis unit for producing hydrogen is arranged in the device. In addition, the invention also relates to a method for operating such a device. Background Art

[0002] Due to ongoing climate change, government regulations regarding the permitted emission of CO2 into the atmosphere are becoming increasingly stringent. Therefore, especially in the field of transportation, people are trying to find alternatives to the known fossil fuels (diesel, gasoline, natural gas, etc.). One possible path is, for example, to use a battery-driven vehicle with an electric drive. Here, the previously generated electrical energy is stored in the battery and used to drive the electric motor. However, the extent of the reduction in CO2 depends to a large extent on the type of power generation and also on the energy input for manufacturing the battery. However, especially for commercial vehicles, pure battery-powered operation is currently not economical and practical, mainly because of the unfavorable ratio of weight or structural size to storage capacity. Therefore, suitable batteries will be too large and / or too heavy, which is unacceptable for the restriction of transportation capacity.

[0003] Another possibility is to drive the vehicle with hydrogen. In this case, hydrogen can be used, for example, as a fuel for a modified internal combustion engine or it can be converted into electrical energy in a fuel cell, which in turn can be used to drive an electric motor. Hydrogen can be stored, for example, in liquid form in suitable cryogenic tanks or in gaseous form under sufficiently high pressure in pressure vessels. This makes it possible to achieve similarly high ranges in commercial vehicles as with previous drives. Electrolysis for the production of hydrogen is well known in the prior art. In this case, water is decomposed into hydrogen (H) using electrical energy. 2 ) and oxygen (O 2 ). Various types of electrolysis cells, so-called electrolyzers, are known in this regard, with different structures. Hydrogen is provided at a certain pressure at the output of the electrolysis cell (regardless of its design). Thus, in the process of hydrogen production, CO is reduced. 2 It also depends on the type of power generation used to power the electrolysis unit.

[0004] Therefore, it is particularly advantageous to use renewable energy carriers (such as wind power or photovoltaics) to power the electrolysis unit. In contrast to conventional energy carriers (especially fossil energy carriers), power generation is usually not always maintained at a constant level, but rather depends to a large extent on the environmental conditions existing at the time. The power generation of wind power plants varies with the strength of the wind and is therefore naturally not constant. The power generation of photovoltaic plants varies with the strength of solar radiation, which is also usually not constant, for example, due to clouds or the sun being blocked. If the electrolysis unit is directly connected to a corresponding power source, the power supply of the electrolysis unit will therefore also fluctuate with the fluctuations in the power generation of the power source. However, fluctuations in the power supply of the electrolysis unit are undesirable because they will lead to pressure fluctuations in the hydrogen produced at the output end of the electrolysis unit. These pressure fluctuations in turn have an adverse effect on the durability of the electrolysis unit and thus affect its service life. Summary of the invention

[0005] It is therefore an object of the present invention to provide a device for providing hydrogen by means of an electrolysis cell which enables the longest possible service life of the electrolysis cell even in the event of fluctuations in the power supply to the electrolysis cell.

[0006] This object is achieved with the device described at the outset in that a reciprocating piston compressor for compressing the hydrogen produced by the electrolysis cell is provided, the reciprocating piston compressor having at least one automatic intake valve; a lifting catch is provided for selectively holding the intake valve in an open position; an electrically controllable actuator is provided for operating the lifting catch; and a control unit is provided for controlling the actuator, wherein the control unit is designed to control the actuator in such a way that the output pressure of the hydrogen at the output of the electrolysis cell or the pressure difference between the anode and cathode of the electrolysis cell can be adjusted to a predetermined setpoint value. If the electrolysis cell has a proton exchange membrane between the anode and the cathode, the pressure difference can be the pressure difference across the proton exchange membrane. Thus, for example, in the event of fluctuations in the power supply to the electrolysis cell, which fluctuations have previously led to fluctuations in the output pressure, the desired setpoint value of the output pressure can be adjusted relatively quickly by controlling the lifting catch.

[0007] As the setpoint value, for example, a defined value can be provided, or a function can also be stored in the control unit, which determines the setpoint value in dependence on at least one further variable, preferably time. Thus, a constant output pressure or pressure difference can be set regardless of possible power supply fluctuations. As an alternative, a specific time profile of the output pressure or pressure difference can also be set. For example, this profile can be set in an advantageous manner when the electrolysis unit is shut down or when the power supply is interrupted, so that the output pressure is reduced relatively slowly and in a controlled manner to a certain pressure.

[0008] Preferably, a determination unit is provided for determining the actual value of the output pressure or the pressure difference, and the control unit is configured to use the determined actual value to adjust the output pressure or the pressure difference to a predetermined nominal value. Preferably, the determination unit has at least one sensor and / or a calculation model, wherein the calculation model is preferably stored in the control unit. As a sensor, for example, a pressure sensor can be provided for detecting the actual value of the output pressure of the hydrogen at the output of the electrolysis unit. The pressure sensor can be arranged in a connecting line that connects the output of the electrolysis unit to the piston compressor. A pressure difference sensor can also be provided for detecting the actual value of the pressure difference.

[0009] Preferably, the control unit is designed to determine a manipulated variable for the actuator from a determined actual value and a predetermined setpoint value and to control the actuator with the determined manipulated variable. It is advantageous for this to include a suitable controller, such as a PI controller or a PID controller, for determining the manipulated variable. In this way, a closed control loop can be realized, so that the output pressure or pressure difference can be adjusted very precisely.

[0010] As a supplement or alternative, a function for determining a manipulated variable for the actuator in relation to a predetermined setpoint value can be stored in the control unit, and the control unit can be designed to determine the manipulated variable for the actuator from the function and to control the actuator with the determined manipulated variable. This makes it possible to implement a (feedforward) control that is simpler than a (feedback) control. The function can be considered to be known or can be determined experimentally, as appropriate.

[0011] Preferably, a power source is provided for supplying power to the electrolysis unit and / or the reciprocating piston compressor. Thus, for example, the entire device can be supplied with power by a single power source. Particularly preferably, the power source comprises a regenerative energy generator, which is connected to the electrolysis unit and / or to the reciprocating piston compressor, wherein the energy generator preferably comprises a photovoltaic system or a wind power plant. Thus, hydrogen can be produced using renewable energy carriers, which is advantageous for ecological reasons. Since the regenerative energy generator generally produces energy that is not constant in time due to environmental conditions, the control or regulation of the output pressure or pressure difference according to the invention is particularly advantageous, since in this way, for example, fluctuations can be quickly and easily compensated.

[0012] The actuator is preferably designed as a pneumatic, hydraulic or electromagnetic actuator. Due to the short reaction time, electromagnetic actuators are particularly advantageous for being able to react as quickly as possible to rapid pressure fluctuations.

[0013] Advantageously, the at least one automatic suction valve is configured as an annular valve, wherein the annular valve preferably has a plurality of annular valve holes and a plurality of annular valve elements, which can be operated by a lifting gripper. This design has been proven in compressors to date.

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

[0015] The electrolysis unit can be supplied with electrical energy which is not constant over time, for example, directly from a regenerative energy generator, and the control unit can regulate the output pressure or the pressure difference to a predetermined (for example constant) setpoint value.

[0016] When the electrolysis unit is stopped or the power supply to the electrolysis unit is interrupted, the control unit can also reduce the output pressure to a specified value, for example, according to a predetermined time function. Therefore, the output pressure can, for example, slowly decrease, which is beneficial for the durability of the electrolysis unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Please refer to the following Figure 1 The invention is explained in detail, and the accompanying drawings show an advantageous structural design of the invention by way of example, schematically and non-limitingly. The accompanying drawings show:

[0018] Figure 1 is an exemplary embodiment of the present invention of an apparatus for providing hydrogen. DETAILED DESCRIPTION

[0019] Figure 1 The device 1 shown in FIG. 1 has a device for producing hydrogen H 2 The electrolysis unit 2 and a device for compressing the hydrogen H produced by the electrolysis unit 2 2 A reciprocating piston compressor 3 is provided. In addition, a control unit 4 is provided for controlling the device 1. The control unit 4 has suitable hardware and / or software. Such a control unit 4 is known in the prior art and will not be described in detail here. Figure 1 The control unit 4 is designed to control the electrolysis unit 2 and the piston compressor 3, for example. However, this is only exemplary. Figure 1As shown in the figure, it is also possible to provide an independent electrolysis control unit 4a for the electrolysis unit 2 and an independent compressor control unit 4b for the piston compressor 3. The control units 4a, 4b can communicate with each other in a suitable manner in this case to exchange sensor signals and / or control signals, which will be described in detail below. However, in principle, it is also sufficient within the scope of the present invention to provide only one compressor control unit 4b for controlling the piston compressor 3. This depends essentially on the selection of the operating parameters of the electrolysis unit 2 to be set, which will be described in detail below.

[0020] In the example shown, a power source 13 is provided for supplying energy to the electrolysis unit 2 and the reciprocating piston compressor 3. The power source 13 has, for example, a regenerative energy generator 13a, which is connected to the drive unit AE of the electrolysis unit 2 and the reciprocating piston compressor 3. In an advantageous embodiment, as in Figure 1 As shown in , the energy generation device 13a has, for example, a photovoltaic system. As an alternative or in addition, the energy generation device 13a can also have a wind power plant (not shown) or other suitable regenerative energy generation device 13a.

[0021] The structure and function of the reciprocating piston compressor 3 are well known, so Figure 1 The reciprocating piston compressor 3 is shown only schematically in FIG. In a known manner, the reciprocating piston compressor 3 has several cylinders Z, in each of which a piston K can move back and forth in an oscillating stroke movement H between the top dead center and the bottom dead center. Figure 1 In the example, a single cylinder Z is shown, but the reciprocating piston compressor 3 can of course also have a plurality of cylinders Z. In the example shown, the piston K is driven via a piston rod KS which is connected to a crosshead KK.

[0022] The crosshead KK is connected to a crankshaft connecting rod mechanism (schematically shown). The crankshaft connecting rod mechanism has a crankshaft KW, and each piston K has a connecting rod P. The crankshaft KW is driven by a suitable drive device AE, such as an electric motor. The drive device AE is powered by the same power supply 13 as the electrolysis unit 2. However, the drive device AE of the piston compressor 3 can certainly also be supplied with driving energy by an independent energy source. The crosshead KK is connected to the crankshaft KW through the connecting rod P and is driven by the crankshaft. The crosshead supports the lateral force generated by the connecting rod P on the housing of the reciprocating piston compressor 3, so that the piston rod KS performs a basically pure oscillating movement that is as unaffected by the lateral force as possible. However, in principle, the piston compressor 3 can also be equipped with no crosshead KK, wherein the piston K is driven directly by the connecting rod P in this case.

[0023] A compression chamber KR is provided in the cylinder Z, which is delimited on one side by the movable piston K and on the other side by the wall of the piston compressor 3, for example by the cylinder cover ZK. In the region of the compression chamber KR, at least one intake valve 5 and at least one pressure valve 8 are provided for gas exchange. In contrast to the arrangement shown, it is of course also possible to provide a plurality of intake valves 5 and / or a plurality of pressure valves 8. Of course, they can also be arranged radially on the cylinder Z. During the expansion stroke of the piston K, the compressed medium (here the hydrogen H produced by the electrolysis unit 2) is compressed. 2 ) is sucked in through the opened intake valve 5 and flows into the compression chamber KR. The compression medium is compressed in the subsequent compression stroke of the piston K. When a specified pressure is reached, the pressure valve 8 opens and the pressure medium can flow through the opened pressure valve 8. The compressed compression medium can then be supplied, for example, to a suitable (not shown) storage container or a (not shown) consumer, such as a fuel cell.

[0024] The reciprocating piston compressor 3 has at least one automatic suction valve 5, which opens automatically during the expansion stroke of the piston K depending on the pressure conditions and closes automatically during the compression stroke of the piston K. Therefore, no external energy, such as an actuator, is required for valve operation. In addition, a lifting gripper 6 is provided, with which the suction valve 5 can be selectively kept in an open position regardless of the pressure conditions at the time. The suction valve 5 is preferably configured as an annular valve, wherein the annular valve preferably has a plurality of annular valve holes 5a and a plurality of annular valve elements 5b. The valve element 5b seals the valve hole 5a in the closed state of the annular valve 5. In this case, the lifting gripper 6 preferably has a plurality of lifting gripping fingers, which can operate the valve element 5b through the valve hole 5a. This type of annular valve is known in the prior art, so it will not be described in detail here.

[0025] Furthermore, an electrically controllable actuator 7 is provided for operating the lifting gripper 6. The actuator 7 can be designed, for example, as a pneumatic, hydraulic or electromagnetic actuator, wherein electromagnetic operation is preferred due to the short switching time. Figure 1 5 is only schematically shown and can, for example (similar to the suction valve 5) also be configured as an automatic valve. In this case, the valve element opens towards the side facing away from the compression chamber KR under certain pressure conditions. However, as an alternative, of course, another suitable valve, for example a non-automatic valve, can also be provided as the pressure valve 8, which can be operated by a suitable actuator.

[0026] In contrast to the embodiment shown, the reciprocating piston compressor 3 can also be designed as a double-acting reciprocating piston compressor, for example. In this case, a first compression chamber KR is provided in the cylinder Z on the side of the piston K facing away from the crankshaft connecting rod mechanism (e.g., Figure 1As shown in FIG), and in addition, a second compression chamber KR (not shown) is also provided on the side of the piston K facing the crankshaft connecting rod mechanism. Of course, at least one suction valve and a pressure valve are provided on the second compression chamber KR for gas exchange.

[0027] Of course, the reciprocating piston compressor 3 can also be constructed as a multi-stage compressor. In this case, multiple cylinders Z are provided, which have multiple compression chambers KR with different compression ratios. In this case, the pressure valve of the first compression chamber is connected to the suction valve of the second compression chamber behind. The compressed medium (here, hydrogen H 2 ) is then compressed in several stages to the desired final pressure. Double-acting reciprocating piston compressors and multi-stage compressors are known in the prior art. Of course, it is also conceivable to combine a double-acting reciprocating piston compressor with a multi-stage compressor. In this case, it is advantageous if at least the first compressor stage at the outlet of the electrolysis unit 2 has an automatic suction valve 5 with a lifting catch and an actuator 7.

[0028] The control unit 4 (or the compressor control unit 4 b) is designed to control the actuator 7 in such a way that the hydrogen H at the outlet of the electrolysis unit 2 2 The output pressure p1 or the pressure difference Δp between the anode and cathode of the electrolysis unit 2 can be adjusted to a predetermined setpoint value. If the electrolysis unit 2 has a polyelectrolyte membrane electrolysis device 2a with a proton exchange membrane between the anode and the cathode, the pressure difference Δp is preferably the pressure difference Δp across the proton exchange membrane 11. The reciprocating piston compressor 3 is preferably operated at a prescribed constant speed during operation of the device 1. For this purpose, the control unit 4 (or the compressor control unit 4b) can control the drive unit AE of the reciprocating piston compressor 3 accordingly.

[0029] Preferably, a setpoint value is predetermined for the operating parameter, for example the hydrogen H at the output of the electrolysis unit 2 2 The control unit 4 can use the predetermined setpoint value to control or regulate the actuator 7. Thus, for example, the hydrogen H at the outlet of the electrolysis unit 2 can be regulated by controlling the at least one intake valve 5 using the lifting gripper 6. 2 A constant output pressure p1 or a constant pressure difference Δp across the membrane 11 is thus ensured. Even if the power supply of the power source 13 (e.g. the photovoltaic device 13a) fluctuates, it is still possible to ensure that the output pressure p1 or the pressure difference Δp remains constant. Normally, fluctuating energy supply leads to pressure fluctuations in the output pressure p1, which, however (as mentioned at the beginning), has an adverse effect on the durability of the electrolysis unit 2, in particular the durability of the membrane 11.

[0030] The setpoint value can be, for example, a specified value, such as a setpoint output pressure p1_soll in the range of 15 bar to 40 bar, or a predetermined setpoint pressure difference Δp_soll. In the case of full load of the electrolysis unit 2, the setpoint output pressure p1_soll can be, for example, in the range of 30 bar. In the case of partial load, the setpoint output pressure p1_soll can be, for example, in the range of 25 bar. In addition, it can also be advantageous to keep the output pressure p1 at a specified value after the electrolysis unit 2 has been shut down. This can facilitate a quick restart of the electrolysis unit 2.

[0031] A function for determining a setpoint value as a function of at least one other variable, for example as a function of time, can also be stored in the control unit 4. Thus, for example, when shutting down the electrolysis cell 2, the output pressure p1 can be reduced in a controlled manner from a first value to a lower second value, for example as a function of time in the form of a ramp. Thus, a sudden drop in pressure at the output of the electrolysis cell 2 after shutting down the electrolysis cell 2, which drop could have a negative effect on the durability of the electrolysis cell 2, can be prevented.

[0032] For (feedback) control, a determination unit is preferably provided for determining an actual value p1_ist of the output pressure p1 or an actual value Δp_ist of the pressure difference Δp. The control unit 4 is preferably designed in this case to use the determined actual value to adjust the output pressure p1 or the pressure difference Δp to a predetermined setpoint value.

[0033] The determination unit can have at least one sensor and / or a calculation model, wherein the calculation model is preferably stored in the control unit 4. Figure 1 As shown in FIG. 1 , for example, a pressure sensor 10 a can be provided for measuring an actual value p1_ist of the output pressure p1 of the electrolysis cell 2. The pressure sensor 10 a can be provided, for example, directly at the output of the electrolysis cell 2 and / or can be part of the electrolysis cell 2. The pressure signal measured by the pressure sensor 10 a can then be transmitted to the control unit 4 and processed by the control unit to control 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 can, for example, also be transmitted to the electrolysis control unit 4a and from there to the compressor control unit 4b. Of course, the sensor signal can also be transmitted 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 regulation, since in this case it would be impossible to operate the electrolysis control unit 4a.

[0035] As in Figure 1As shown in FIG. 1 , the output end of the electrolysis unit 2 can be connected to the piston compressor 3 through a connecting line L, in particular, to the suction line of the piston compressor 3. Then, the generated hydrogen H 2 The at least one automatic suction valve 5 of the piston compressor 3 is supplied. The pressure sensor 10a can then be arranged, for example, in the connecting line L. If necessary, e.g. Figure 1 As shown by the dashed line in the figure, another device 12, such as a filter, can also be arranged between the output end of the electrolysis unit 2 and the input end of the piston compressor 3. In this case, the pressure sensor 10a can be arranged before or after the filter 12 in the flow direction. Generally speaking, the output pressure p1 within the scope of the present invention refers to the pressure at any point in the connecting line L between the output end of the electrolysis unit 2 and the input end of the piston compressor 3.

[0036] As an alternative or in addition to the pressure sensor 10a, it may also be advantageous if a differential pressure sensor 10b is provided for detecting the actual value Δp_ist of the differential pressure Δp across the membrane 11. This makes it possible not only to control the output pressure p1 but also, for example, to adjust to a constant differential pressure Δp across the membrane 11. This is advantageous because the membrane 11 of the electrolysis device 2a is relatively sensitive to excessive differential pressures between the anode side and the cathode side. As differential pressure sensor 10b, one suitable sensor may be used, or two pressure sensors may be used, from the difference of which the required differential pressure Δp may be determined (for example by the control unit 4).

[0037] As an alternative or supplementary solution to possible sensors, the determination unit may also have a calculation model for determining the actual value. The calculation model may be stored in the control unit 4, for example, in the form of a mathematical function, a characteristic curve or a family of characteristic curves. The calculation model may be known, for example, it may be given in advance by the manufacturer of the electrolysis unit 2. As an alternative, for example, it may also be determined experimentally based on experience. The actual value p1_ist of the output pressure p1 or the actual value Δp_ist of the pressure difference Δp may be calculated from other available variables through the calculation model. For example, it may be considered to determine the hydrogen H at the output end of the electrolysis unit 2 from an electrical measurement variable (for example, from the current current, current voltage or current electrical power of the electrolysis unit 2). 2 The output pressure p1 of the embodiment of the present invention is 0. The electrical measured variable can be detected relatively easily by a suitable measuring device.

[0038] The measuring device for detecting the electrical measured variable (current, voltage, power) can be integrated, for example, in the electrolysis cell 2 as an integral component of the electrolysis cell 2. The measured variable can in this case be transmitted to a control unit 4 (for example, an electrolysis control unit 4a) and used as an input variable in a calculation model by the control unit 4. The control unit 4 can, for example, determine the actual value p1_ist of the output pressure p1 at the output of the electrolysis cell 2 as an output variable.

[0039] However, as an alternative, a separate measuring device (not shown) for measuring the electrical measured variable (current, voltage, power) can also be provided, which is not a component of the electrolysis cell 2. The separate measuring device can be arranged, for example, on a power supply line, via which the electrolysis cell 2 is supplied with power by the power supply 13. The measured variable measured by the separate measuring device can also be transmitted to the control unit 4 (in this case, for example, to the compressor control unit 4b) and used by the control unit 4 as an input variable in the calculation model. The variant with separate measuring device can also be used in an advantageous manner for retrofitting existing electrolysis cells 2.

[0040] The control unit 4 can determine a suitable manipulated variable S1 for the actuator 7 from a determined actual value (e.g., an actual value p1_ist of the output pressure p1 or an actual value Δp_ist of the pressure difference Δp) and a predetermined setpoint value (e.g., a constant setpoint value p1_soll of the output pressure p1 or a constant setpoint value Δp_soll of the pressure difference Δp), and control the actuator 7 with the determined manipulated variable S1. In order to determine the manipulated variable S1, a suitable controller, such as a PI controller or a PID controller, is preferably provided in the control unit 4. The type of manipulated variable S1 depends on the specific design of the actuator 7 and can be, for example, a current or a voltage. The actuator 7 then regulates, preferably steplessly regulates, the lifting grab 6 according to the manipulated variable S1 to operate the intake valve 5 to adjust the output pressure p1 or the pressure difference Δp.

[0041] However, in principle, it is not necessary to provide a (feedback) control, but (feedforward) control can also be used. For this purpose, for example, in order to determine the manipulated variable S1 for the actuator 7, a function of the manipulated variable S1 that is related to a predetermined setpoint value (for example, a setpoint value p1_setpoint of the output pressure p1 or a setpoint value Δp_setpoint of the pressure difference Δp) can be stored in the control unit 4. The control unit 4 can then determine the manipulated variable S1 for the actuator 7 based on the setpoint value from the function and control the actuator 7 with the determined manipulated variable S1. The function can, for example, be stored in the control unit 4 as a mathematical function, a characteristic curve or a family of characteristic curves. The function can be known, or a suitable function can be determined, for example, by experiment.

[0042] The electrolysis unit 2 can, for example, be supplied with electrical energy that is not constant in time directly (i.e., without the need for an intervening electrical consumer or accumulator) from the regenerative energy generation device 13a. In this case, the control unit 4 can adjust the output pressure p1 or the pressure difference Δp to a predetermined (e.g., constant) rated value as described above. When the electrolysis unit 2 stops operating or the power supply to the electrolysis unit 2 is interrupted, the control unit 4 can, for example, also reduce the output pressure p1 to a specified value according to a predetermined time function. Therefore, when the electrolysis unit 2 is closed, the output pressure p1 can, for example, drop from a full load pressure of about 30 bar to a specified lower pressure in a controlled manner within a predetermined time. If the electrolysis unit 2 is only closed briefly, the output pressure p1 can also be maintained at a relatively high value, which is within the range of the output pressure p1 before closing, by correspondingly controlling the actuator 7, for example.

Claims

1. A device (1) for providing hydrogen (H2), wherein an electrolysis unit (2) for producing hydrogen (H2) is provided in the device (1), characterized in that: A reciprocating piston compressor (3) for compressing hydrogen (H2) produced by the electrolysis unit (2) is provided, the reciprocating piston compressor (3) having at least one automatic suction valve (5); a lifting catch (6) is provided for selectively holding the suction valve (5) in an open position; An electrically controllable actuator (7) is provided for operating a lifting gripper (6); and a control unit (4) is provided for controlling the actuator (7), the control unit (4) being designed to control the actuator (7) in such a way that an output pressure (p1) of hydrogen (H2) at an output of an electrolysis unit (2) or a pressure difference (Δp) between an anode and a cathode of the electrolysis unit (2) can be adjusted to a predetermined setpoint value (p1_setpoint, Δp_setpoint).

2. The device (1) according to claim 1, characterized in that: The electrolysis unit (2) has a proton exchange membrane (11) between the anode and the cathode, and the pressure difference (Δp) is the pressure difference (Δp) across the proton exchange membrane (11).

3. The device (1) according to claim 1 or 2, characterized in that: The setpoint value (p1_setpoint, Δp_setpoint) is a defined value, or a function is stored in the control unit (4) for determining the setpoint value (p1_setpoint, Δp_setpoint) in a manner that is preferably time-dependent and dependent on at least one further variable.

4. The device (1) according to any one of claims 1 to 3, characterized in that: A determination unit is provided for determining an actual value (p1_ist, Δp_ist) of an output pressure (p1) or a pressure difference (Δp), and the control unit (4) is designed to use the determined actual value (p1_ist, Δp_ist) to adjust the output pressure (p1) or the pressure difference (Δp) to a predetermined setpoint value (p1_soll, Δp_soll).

5. The device (1) according to claim 4, characterized in that: The determination unit has at least one sensor (10a, 10b) and / or the determination unit has a calculation model which is preferably stored in the control unit (4).

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

7. The device (1) according to any one of claims 4 to 6, characterized in that: The control unit (4) is designed to determine a manipulated variable (S1) for an actuator (7) from a determined actual value (p1_ist, Δp_ist) and a predetermined setpoint value (p1_soll, Δp_soll), and to control the actuator (7) using the determined manipulated variable (S1), wherein the control unit (4) preferably has a controller, such as a PI controller or a PID controller, for determining the manipulated variable (S1).

8. The device (1) according to any one of claims 1 to 7, characterized in that: A function is stored in the control unit (4) for determining a manipulated variable (S1) as a function of a predetermined setpoint value (p1_setpoint, Δp_setpoint), and the control unit (4) is designed to determine a manipulated variable (S1) for an actuator (7) from the function and to control the actuator (7) using the determined manipulated variable (S1).

9. The device (1) according to any one of claims 1 to 8, characterized in that: A power source (13) is provided for supplying energy to the electrolysis unit (2) and / or the reciprocating piston compressor (3).

10. The device (1) according to claim 9, characterized in that: The power source (13) has a regenerative energy generation device (13a), which is connected to the electrolysis unit (2) and / or to the reciprocating piston compressor (3). The energy generation device (13a) preferably has a photovoltaic device or a wind power generation device.

11. The device (1) according to any one of claims 1 to 10, characterized in that: The actuator (7) is designed as a pneumatic, hydraulic or electromagnetic actuator.

12. The device (1) according to any one of claims 1 to 11, characterized in that: The at least one automatic suction valve (5) is designed as an annular valve, wherein the annular valve preferably has a plurality of annular valve openings and a plurality of annular valve elements, which can be operated by a lifting gripper (6).

13. The device (1) according to any one of claims 1 to 12, characterized in that: The reciprocating piston compressor (3) is configured as a double-acting reciprocating piston compressor and / or a multi-stage reciprocating piston compressor.

14. Method for operating a device (1) according to any one of claims 1 to 13, characterized in that: Hydrogen (H2) is generated by an electrolysis unit (2), the generated hydrogen (H2) is supplied to a reciprocating piston compressor (3) via the at least one intake valve (5) and is compressed by the reciprocating piston compressor (3), a setpoint value (p1_setpoint, Δp_setpoint) for an output pressure (p1) or a pressure difference (Δp) is predetermined, and the control unit (4) controls an actuator (7) in order to adjust the setpoint value (p1_setpoint, Δp_setpoint).

15. The method according to claim 14, characterized in that: Predefined values ​​are used as setpoint values ​​(p1_setpoint, Δp_setpoint), or the setpoint values ​​(p1_setpoint, Δp_setpoint) are determined from a function that is dependent on at least one further variable, preferably time.

16. The method according to claim 14 or 15, characterized in that: During operation of the device (1), an actual value (p1_ist, Δp_ist) of an output pressure (p1) or a pressure difference (Δp) is determined, and the control unit (4) determines a manipulated variable (S1) for an actuator (7) from the actual value (p1_ist, Δp_ist) and a 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. The method according to claim 14 or 15, characterized in that: A manipulated variable (S1) for an actuator (7) is determined from a function of the manipulated variable (S1) that is dependent on a predetermined setpoint value (p1_setpoint, Δp_setpoint), and a control unit (4) controls the actuator (7) using the determined manipulated variable (S1).

18. The method according to any one of claims 14 to 17, characterized in that: The electrolysis unit (2) is supplied with temporally non-constant electrical energy directly from a regenerative energy generator (13a), and the control unit (4) regulates the output pressure (p1) or the pressure difference (Δp) to a predetermined setpoint value (p1_setpoint, Δp_setpoint).

19. The method according to any one of claims 14 to 17, characterized in that: The electrolysis unit (2) is stopped or the power supply to the electrolysis unit (2) is interrupted, and the control unit (4) reduces the output pressure (p1) to a specified value according to a predetermined time function.

20. The method according to any one of claims 14 to 19, characterized in that: The reciprocating piston compressor (3) operates at a prescribed constant speed.

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