APPARATUS FOR GENERATING A GAS

Abstract

Useful apparatus for generating a gas, comprising an enclosure defining an internal space for containing a liquid capable of generating the gas by coming into contact with a catalyst, a catalytic system comprising first and second parts that together define a catalysis chamber for containing the catalyst and that are movable relative to each other between a closed position, in which the catalysis chamber is isolated from the internal space, and an open position, in which the catalysis chamber is in fluid communication with the internal space, so that, when the liquid and the catalyst are respectively contained in the internal space and in the catalysis chamber, in the open position, the liquid enters the catalysis chamber and the gas is generated by bringing the liquid into contact with the catalyst, an actuator connected to the catalytic system and configured to place the catalytic system in the open position and/or in the closed position, and a command unit for commanding the actuator.

Claims

1. An apparatus for generating a gas, the apparatus comprising: an enclosure defining an internal space for containing a liquid capable of generating the gas by coming into contact with a catalyst; a catalytic system comprising first and second parts that together define a catalysis chamber for containing the catalyst, the first and second parts being movable relative to each other, between a closed position, in which the catalysis chamber is isolated from the internal space, and an open position, in which the catalysis chamber is in fluid communication with the internal space, so that, when the liquid and the catalyst are respectively contained in the internal space and in the catalysis chamber, in the open position, the liquid enters the catalysis chamber and the gas is generated by bringing the liquid into contact with the catalyst; an actuator connected to the catalytic system and configured to place the catalytic system in the open position and/or in the closed position; and a command unit for commanding the actuator.

2. The apparatus according to claim 1, wherein the actuator is a hydraulic ram or an electric ram or a pneumatic ram or an electric motor.

3. The apparatus according to claim 2, wherein, in at least one of the open and closed positions of the catalytic system, at least one part of the ram is disposed in the housing and/or the catalytic system is disposed in the internal space of the enclosure.

4. The apparatus according to claim 2, wherein the ram is hydraulic or pneumatic, the apparatus comprising a command valve connected to the command unit and to the ram, the command valve being configured to receive a command signal originating from the command unit and to deliver an amount of pressurized fluid to the ram and/or to purge the ram of said fluid, following the reception of said command signal.

5. The apparatus according to claim 4, comprising a pressurized fluid supply component in fluid communication with the command valve, and an assembly formed by a tank comprising the pneumatic fluid connected to a compressor or to a pump for compressing the fluid.

6. The apparatus according to claim 1, wherein the command unit is configured to command the actuator according to at least one control mode configured by means of at least one control parameter.

7. The apparatus according to claim 6, wherein the control mode is a regulation mode configured by means of control parameters comprising first and second regulation parameters, and the command unit is configured to receive a quantity to be regulated, and to command the actuator so as to place the catalytic system in a first position and a second position, respectively, when the quantity to be regulated is less than the first regulation parameter, and is respectively greater than the second regulation parameter.

8. The apparatus according to claim 6, comprising a control unit configured to: receive at least one quantity to be controlled; analyze the quantity to be controlled; and depending on the result of the analysis: generate a control signal according to the regulation mode or to a specific control mode different from the regulation mode; and send the control signal to the command unit that is configured to receive said control signal and to command the actuator according to the control mode corresponding to the control signal.

9. The apparatus according to claim 1, comprising a unit for measuring a quantity selected from the gas pressure in the internal space, the pressure of the gas in a machine, with which the apparatus is in fluid communication, the generated gas flow rate and a temperature, the measurement unit being configured to send the measured quantity to the command unit and/or to the control unit.

10. The apparatus according to claim 9, wherein, depending on the control mode to be implemented by the command unit, the quantity measured by the measurement unit is a quantity to be regulated and/or a quantity to be controlled.

11. The apparatus according to claim 1, comprising the catalyst, with at least one portion of the catalyst being fixed to the first part and/or to the second part, and/or the internal space contains the liquid.

12. The apparatus according to claim 1, wherein a wall of the first part, respectively of the second part, comprises at least one window passing through the thickness of said wall, the window of the first part, respectively of the second part, being completely sealed by the second part, respectively by the first part, in the closed position of the catalytic system, and the windows of the first and second parts define an access path for the liquid through the walls of the first and second parts toward the catalysis chamber in the open position of the catalytic system.

13. A method for generating a gas, wherein an apparatus according to claim 1 is provided, the internal space of the enclosure containing a liquid capable of generating the gas through contact with a catalyst, and the catalysis chamber of the catalytic system containing said catalyst, the method being implemented according to a control mode, called regulation mode, configured by means of first and second regulation parameters, the method comprising steps involving measuring a quantity to be regulated and commanding the actuator to place the catalytic system in first and second positions, respectively, when the quantity to be regulated is less than, respectively greater than, the first regulation parameter and, respectively, the second regulation parameter.

14. The method according to claim 13, wherein the quantity to be regulated is selected from the gas pressure in the internal space, the pressure of the gas in a machine, with which the apparatus is in fluid communication, the generated gas flow rate and a temperature, and the first and second regulation parameters are respectively minimum and maximum values of the quantity to be regulated.

15. The method according to claim 14, wherein the quantity to be regulated is the gas pressure in the internal space, and the first and second regulation parameters are respectively minimum and maximum regulation pressures.

16. The method according to claim 13, wherein: at least one quantity to be controlled is measured; the quantity to be controlled is analyzed, in particular by comparing it with at least one control parameter; and depending on the result of the analysis, the method ceases to be controlled according to the regulation mode, then the method is controlled according to a specific control mode different from the regulation mode.

17. The method according to claim 16, wherein: the quantities to be controlled are the temperature of the liquid and/or the temperature of the environment of the apparatus and/or the temperature of the catalyst, and the control parameters respectively are a minimum control temperature of the liquid and/or a minimum control temperature of the environment and/or a minimum control temperature of the catalyst; an analysis is started that involves verifying whether, during an analysis duration, the temperature of the liquid and/or the temperature of the environment of the apparatus and/or the temperature of the catalyst are respectively less than the minimum control temperature of the liquid and/or a minimum control temperature of the environment and/or the minimum control temperature of the catalyst and, if this is the case, the method ceases to be controlled according to the regulation mode, then the method is controlled according to a cold control mode, in which the quantity to be controlled is the pressure of the gas in the enclosure, and: i) optionally, the actuator is commanded so as to place the catalytic system in the open position; then ii) the actuator is commanded so as to place and hold the catalytic system in the closed position as long as the pressure of the gas in the enclosure is less than a maximum setpoint pressure; iii) the actuator is commanded so as to place and hold the catalytic system in the open position and the enclosure is opened so that the generated gas is discharged from the enclosure; and if, during step iii) the measured gas pressure becomes less than, then greater than a minimum setpoint pressure, the method ceases to be controlled according to the cold control mode; otherwise steps i) and ii) are performed.

18. The method according to claim 17, wherein the minimum control temperature of the liquid and/or the minimum control temperature of the environment and/or the minimum control temperature of the catalyst are equal to 5 C.

19. An electric energy production device, the device comprising: a fuel cell configured to generate an electric current through oxidation of a gas; and a gas generation apparatus according to claim 1, in fluid communication with the fuel cell and configured to supply the fuel cell with said gas.

20. The apparatus according to claim 1, the first and second parts being movable relative to each other by translation and/or by rotation.

21. The apparatus according to claim 4, wherein the ram is pneumatic.

22. The apparatus according to claim 5, the pressurized fluid supply component being a cartridge comprising the pressurized pneumatic fluid.

23. The apparatus according to claim 22, the cartridge being detachably connected to the command valve.

24. The method according to claim 13, the gas being dihydrogen, the liquid being an aqueous hydride solution and the catalyst being selected from platinum, cobalt, ruthenium, nickel and the alloys thereof.

Description

[0144] Further features, variants and advantages of the invention will become more clearly apparent upon reading the following detailed description and examples, which are provided by way of a non-limiting illustration, and with reference to the accompanying drawings, in which:

[0145] FIGS. 1 to 3 schematically show an apparatus according to various embodiments of the invention;

[0146] FIGS. 4 to 6 show enclosures and catalytic systems of apparatus according to various embodiments of the invention viewed as a longitudinal section view;

[0147] FIGS. 7 and 8, on the one hand, and 9 and 10, on the other hand, show enclosures and catalytic systems of apparatus according to various embodiments of the invention viewed as a longitudinal section view in the closed and open position, respectively;

[0148] FIGS. 11 and 12 show the catalytic system of FIGS. 9 and 10, respectively, as a perspective view;

[0149] FIG. 13 shows a device according to one embodiment of the invention;

[0150] FIG. 14 is a graph showing the pressure variation of the gas inside the enclosure during the implementation of the method according to the invention;

[0151] FIG. 15 is a graph showing the pressure variation over time during the implementation of the method according to the invention and of a method of the prior art; and

[0152] FIGS. 16 and 17 shows the pressure variations in the enclosure, the generated gas flow rate, the temperature of the catalyst and the temperature of the environment during the implementation of the method.

[0153] Throughout the figures, the scales and proportions of the various components and units forming the apparatus and the device are not necessarily followed. Furthermore, for the sake of clarity, components can be shown as not being in contact with one another whilst they are in practice. Different reference signs can denote the same component.

[0154] FIG. 1 shows a first embodiment of the apparatus according to the invention.

[0155] The apparatus 5 comprises: [0156] an enclosure 10 defining an internal volume 15, in which a catalytic system 20 and a pressure measurement unit 25, temperature measurement units 26, 27 and 28, and a generated gas flow rate measurement unit 29 are disposed; [0157] an actuator in the form of a pneumatic ram 30 fixed on the enclosure and on the catalytic system; [0158] a command valve 35 in fluid communication, on the one hand, with the ram, in order to deliver a pressurized fluid to the ram, and, on the other hand, with a fluid supply component 40; [0159] a command unit 45 electrically connected to the command valve and to the pressure measurement unit; [0160] a control unit 46 electrically connected to the command unit; and [0161] a reader module 50 electrically connected to the command unit and to the control unit.

[0162] The apparatus further comprises a battery 55 for electrically powering the command unit, the control unit, the reader module and the command valve.

[0163] Furthermore, the command unit can comprise a switch 60, so that when the switch is placed in the off position, the command unit is not electrically powered. Preferably then, the catalytic system is placed in the closed position. When the switch is placed in the on position, the command unit is electrically powered.

[0164] The enclosure comprises a side wall 65, which extends in a longitudinal direction X, a lower wall 70 defining a base of the enclosure when the longitudinal direction is parallel to the direction of gravity, and an upper wall, having a gas discharge opening. In one variant, the discharge opening can be surmounted by a valve, preferably a flow control valve. Furthermore, the discharge opening can be surmounted by an overpressure valve, not shown, for discharging the gas when the pressure of the gas in the internal space is greater than a threshold pressure.

[0165] The internal space 15 can contain an aqueous hydride solution 80. Other liquids adapted to form a gas by coming into contact with a catalyst can be contained in the internal space.

[0166] The pressure measurement unit 25 is disposed in the internal space of the enclosure. In the example of FIG. 1, it is disposed in the vicinity of a discharge opening 85 provided in the upper wall of the enclosure. Other arrangements nevertheless can be contemplated.

[0167] The catalytic system 20 comprises a container 90 disposed, preferably rigidly fixed, on the lower wall of the container and a cover 95.

[0168] The container and the cover together define a catalysis chamber 100, in which a catalyst 105 is housed for the hydrolysis of the aqueous hydride solution.

[0169] In the example of FIG. 1, the cover is closed on the container and comprises a gasket seal 110 to seal against the liquid, so that the catalysis chamber is isolated from the internal space 15 of the container. Thus, in the closed position of the apparatus of FIG. 1, the liquid contained in the internal space cannot enter the catalysis chamber.

[0170] The catalyst 105 is fixed on the cover and is in the form of a hollow tube. As will be described hereafter, other arrangements of the catalyst in the catalytic system and other forms can be contemplated.

[0171] Furthermore, holes 115, 120 are respectively provided in the bottom wall of the container of the catalytic system and in the lower wall of the enclosure. They pass through the respective thicknesses of said walls from one end to the other and are fixed facing each other. Preferably, said holes 115 and 120 have identical shapes.

[0172] The ram 30 is disposed in said holes and is rigidly fixed relative to the enclosure. The ram comprises a cylindrical body 125 and a piston 130 housed in the cylindrical body and movable relative to the cylindrical body. In the example of FIG. 1, the hole 115 provided in the lower wall of the enclosure is tapped and the cylindrical body is fixed on the enclosure by screwing the cylindrical body into the tapped hole 115. The ram further comprises a return component 135 in the form of a helical spring fixed at its opposite ends on the body and on the piston, which provides a return function. In one variant, the ram can be of the double acting type, provided with two chambers each supplied with a compressible fluid, with one of the chambers providing the return function. In the closed position of the apparatus shown in FIG. 1, the spring is in an equilibrium position, in which it does not exert a return force on the piston.

[0173] The ram defines a ram chamber 140 for containing a pressurized fluid so as to move the piston between the closed position shown in FIG. 1 and an open position shown in FIG. 2. The end 145 of the piston opposite to that which faces the ram chamber is fixed on the cover. Thus, the cover is translationally movable relative to the enclosure and to the container between the open and closed positions.

[0174] With respect to the command valve 35, it has an inlet 150 connected to the fluid supply component, which in the example of FIG. 1 is a cartridge 155 of pressurized pneumatic fluid, by means of an inlet pipe 160. The command valve has a supply outlet 165 connected to the ram chamber by means of a pipe 170. It further comprises a purge outlet 175, emerging into the environment 180 outside the apparatus where the pressure is lower than the pressure in the cartridge, preferably where the pressure is atmospheric. The valve is electrically connected to the command unit by means of a cable, which command unit is configured to send an electric command signal Sc to the command valve, and the command valve is configured to receive said signal.

[0175] The command signal can be a signal for commanding the opening of the command valve. When the command valve receives such an opening command signal, it is placed in a configuration in which the purge outlet 175 is closed, and the pressurized fluid cartridge is placed in fluid communication with the ram chamber. The fluid can then flow from the cartridge through the supply inlet 150 and outlet 165 of the command valve, up to the ram chamber, as shown by means of the arrows A.sub.g. Thus, the piston 130 can be moved from the closed position to the open position, or held in the open position, as shown in FIG. 2.

[0176] The command signal can be a closure command signal. When the command valve receives a closure command signal it is placed in a configuration in which the inlet 150 of the command valve is closed and in which the purge outlet 175 and the supply outlet 165 are open and in fluid communication. The fluid contained in the ram chamber flows into the supply pipe to the outside of the apparatus, through the purge outlet. With the pressure decreasing in the ram chamber, the piston then moves, under the effect of the return force of the spring or of a back pressure in the variant whereby the ram is of the double acting type, so as to place the catalytic system in the closed position.

[0177] Preferably, the command valve comprises an electric activation component, not shown, for placing the valve in any of the configurations described in the previous two paragraphs, depending on the received electric signal. The electric activation component is electrically connected to the battery.

[0178] The electric signal sent by the command unit to the command valve depends on the result, obtained by the command unit, of the comparison between the minimum regulation pressure and/or the maximum regulation pressure, on the one hand, and the gas pressure measured by the pressure measurement unit, on the other hand.

[0179] In the example of FIG. 1, the pressure measurement unit 25 comprises a pressure sensor 185 for measuring the gas pressure in the enclosure. According to a regulation control mode implemented by the command unit, the pressure measurement unit sends the pressure of the gas that it measures to the command unit, which receives the pressure and compares it with the minimum and maximum regulation pressures. When the gas pressure is less than the minimum regulation pressure, the command unit transmits a command signal to open the command valve so as to open the regulation system. As shown in FIG. 2 using the arrow P, the liquid can then enter the catalysis chamber and come into contact with the catalyst, so that the gas is generated through a reaction between the liquid and the catalyst. The gas then flows under the effect of the Archimedes thrust through the liquid in the enclosure and is discharged through the gas discharge opening 85, as shown by the arrows E, for example, toward the anode chamber of a fuel cell 355, as shown in FIG. 13.

[0180] The generation of gas inside the enclosure results in an increase in the pressure of the gas in the enclosure if said gas is not fully consumed, for example, by a fuel cell as shown in FIG. 13. When the pressure of the gas is greater than the maximum regulation pressure, the command unit transmits a closure command signal to the command valve, so as to place the catalytic system in the closed position. The generation of gas is then stopped. The gas remaining in the enclosure after placing the apparatus in the closed position is discharged from the enclosure if it is consumed, by a fuel cell, for example, so that the gas pressure in the enclosure decreases, until it drops below the minimum regulation pressure. According to the regulation mode, a new gas generation cycle comprising opening the catalytic system as previously described then can be conducted.

[0181] Furthermore, the reader module 50 allows the minimum and/or maximum regulation pressure to be regulated, which pressures are, for example, stored in a storage medium in the form of a file. The reader module reads and sends the value of the minimum regulation pressure and/or the value of the maximum regulation pressure to the command unit, which receives the value in order to compare it with the pressure measured by the gas pressure measurement unit, prior to sending a command signal to the command valve.

[0182] With respect to the control unit 46, even though it is not shown for the sake of clarity, it is electrically connected to the temperature measurement units 26, 27 and 28, to the generated gas flow rate measurement unit 29, and is electrically powered by the battery 55. The temperature measurement unit 26 is disposed in the internal space so as to measure the temperature of the liquid 80. The temperature measurement unit 27 is disposed in the catalysis chamber in contact with the catalyst 105 in order to measure the temperature. The temperature measurement unit 28 is disposed outside the apparatus to measure the temperature of the environment of the apparatus. The generated gas flow rate measurement unit 29 is disposed on the discharge opening 85.

[0183] In the example of FIGS. 1 and 2, each of the measurement units 26 to 28 is configured to send the value of the temperature that it measures to the control unit, which is configured to receive and to control the value. Depending on the regulation mode, the control unit checks whether the temperature of the liquid, the temperature of the catalyst and the temperature of the environment of the apparatus are less than respective minimum control temperatures, for an analysis duration, for example, of 5 seconds. If this is the case, it sends a control signal Sp to the command unit for the command unit to execute a cold control mode.

[0184] The apparatus shown in FIG. 3 differs from that shown in FIGS. 1 and 2 in that it comprises, instead of the fluid cartridge, a fluid supply component 40 comprising a tank 190 for containing the fluid and an electric compressor 195, powered by the battery 55, for compressing the fluid originating from the tank and delivering said fluid to the command valve. In the example of FIG. 3, the fluid is a gas and the ram is pneumatic. In one variant, the fluid is a liquid, for example, an oil and the ram is hydraulic. The compressor 195 is then replaced by a pump.

[0185] Furthermore, the tank comprises an inlet opening 200 in fluid communication with the purge outlet of the command valve. Thus, when the ram is purged of the fluid after receiving a closure command signal, the purged fluid is introduced into the tank. Thus, the fluid supply component, the command valve and the ram form a closed circuit for the fluid.

[0186] As previously stated, the catalytic system comprises first 205 and second 210 parts that together define a catalysis chamber for containing the catalyst. FIGS. 4 to 6 show various examples of catalytic systems, as well as arrangements of the catalyst inside the catalytic system.

[0187] The catalytic system of FIG. 4 differs from that shown in FIG. 1 in that the internal face 212 of the side wall is covered with a coating 215 formed by the catalyst. Such a catalytic system allows the amount of catalyst to be limited whilst having an exchange surface between the catalyst and the liquid for effectively generating the gas.

[0188] The catalytic system of FIG. 5 differs from the catalytic system of FIG. 4 in that the first part 205 is in the form of a plate and the second part 210 is in the form of a bell. The face of the first part facing the second part is covered by a coating 220 formed from the catalyst. The second part has an upper wall 225 fixed to the piston of the ram and a side wall 230 extending in the longitudinal direction of the ram. In one variant, the side wall can be oriented obliquely relative to the longitudinal direction of the ram. The edge of the longitudinal wall of the second part is surmounted by a sealing gasket 110, which presses against the edge of the first part in the closed position to isolate the liquid from the catalyst. The catalytic system of FIG. 5 is easy to manufacture. In particular, the coating can be easily formed on the plate forming the first part at a lower cost. Furthermore, by limiting the height of the walls of the second part, a compact catalytic system thus can be manufactured.

[0189] The catalytic system of FIG. 6 differs from the catalytic system of FIG. 5 in that the height h of the side wall 230 is higher. Thus, the volume of the catalysis chamber 100 of the catalytic system of FIG. 6 is greater than that shown in FIG. 5. Such a system is better adapted than that of FIG. 5 in the event that a significant volume of catalyst is required to implement gas generation.

[0190] FIGS. 7 and 8 show another variant of a catalytic system of an apparatus according to the invention in a closed and open position, respectively.

[0191] The catalytic system 20 shown in FIGS. 7 and 8 differs from the catalytic system of FIG. 1 in that the lower wall 250 of the first part 205 is disposed at a distance from the container 10. Furthermore, the second part 210 has an upper wall 255 in the form of a plate for closing the upper opening 260 of the first part. A tubular portion 265 projects from the upper wall of the second part, in which the piston 130 of the ram is partially housed. Preferably, as is shown, the piston and the tubular portion are of matching shape. At the end thereof that is opposite that which is closed by the cover, the second part has a lower wall 270 extending transversely to the longitudinal direction Y of the ram.

[0192] The lower walls 250, 270 of the first and second parts are each perforated by at least one window, preferably several windows, passing through the thickness of each of said walls. The openings 275, 280 of the lower walls of the first and second parts are disposed so that, in the closed position, as shown in FIG. 7, said lower walls of the first and second parts form a liquid-impermeable assembly, isolating the catalysis chamber from the enclosure, and in the open position, as shown in FIG. 8, they define a fluid access path, shown by the arrow C.sub.1, between the internal space 15 of the enclosure and the catalysis chamber 100 through said lower walls of the first and second parts. Thus, in the open position, the catalytic system defines a fluid access path between the upper wall of the second part and the side wall of the first part, shown by the arrow C.sub.2, and at least one access path between the lower walls of the first and second parts, shown by the arrow C.sub.1. The convection of the liquid inside the catalysis chamber is thus improved, which optimizes the yield of the gas generation reaction. In the example of FIGS. 7 and 8, the transition from the open position to the closed position is performed through a translation movement of the second part relative to the first part.

[0193] FIGS. 9 to 11 show another variant of an apparatus according to the invention, in which the first 205 and second 210 parts are rotationally movable relative to each other between the open and closed positions around an axis Y.

[0194] The first part has a general shape of a rotationally cylindrical and hollow tubular portion 290 and having opposite ends respectively closed by a lower wall 295 and by an upper wall 300 extending in directions transverse to the axis of rotation of the tubular portion. The axis of rotation of the cylindrical tubular portion is parallel to the axis Y.

[0195] Preferably, the upper wall 300 is detachable and is fixed, in particular by screwing, on the tubular portion 290.

[0196] The lower wall 295 of the first part has a recess 305 passing through the thickness of the lower wall and from which a spacer 310 projects. The spacer keeps the tubular portion 290 of the first part at a distance from the enclosure 10. The spacer is in the form of a hollow and cylindrical tube, preferably rotational, coaxial to the tubular portion of the first part.

[0197] Furthermore, the lower, upper and side walls of the first part comprise at least one window 275, preferably several windows, each passing through the thickness of said walls. In one variant, at least one of said walls of the first part may not have windows.

[0198] The second part 210 has a general shape of a rotationally cylindrical hollow tube 320 surmounted at its opposite ends by a lower wall 325 and an upper wall 330, which is preferably detachable. The second part thus defines a catalysis chamber 100 for the catalyst.

[0199] Furthermore, the lower, upper and side walls of the second part comprise at least one window 280, preferably several windows, each passing through the thickness of said walls. In one variant, at least one of said walls of the second part may not have windows.

[0200] The second part is at least partially, even completely, accommodated in the internal space of the tubular portion of the first part, as shown in FIG. 9. The first and second parts have matching shapes and are coaxial.

[0201] The windows of the lower, side and upper walls of the first and second parts are respectively disposed so that, in the closed position, as shown in FIGS. 9 and 11, said lower walls of the first and second parts obstruct the windows of the second and first parts, respectively, and form a liquid-impermeable assembly, isolating the catalysis chamber 100 from the internal space 15 of the enclosure, and in the open position, as shown in FIGS. 10 and 12, they define a fluid access path, shown by the arrow C.sub.1, between the catalysis chamber and the internal space of the enclosure through said lower, side and upper walls of the first and second parts. In FIG. 11, the windows of the second part are shown as dashed lines in order to indicate their angular position relative to the windows of the first part.

[0202] The transition from the closed position to the open position is performed by rotating, by an angle a, the second part relative to the first part about the axis Y. To this end, the second part is fixed on a shaft of a stepper motor 350 engaged in the spacer. The stepper motor comprises a stator and a rotor rotationally movable relative to each other about the axis Y. The stepper motor is electrically powered by the battery and is connected to the command unit. It is configured to drive the second part relative to the first part in the open position or the closed position upon receipt of a signal originating from the control unit.

[0203] FIG. 13 shows a device 350 according to the invention, comprising a fuel cell 355 supplied with dihydrogen by an apparatus 5 according to the invention.

[0204] The fuel cell comprises an oxidation unit 360 including a stack formed by an anode 370, an electrolytic membrane 375 and a cathode 380. It also defines an anode chamber 385 for distributing the dihydrogen to the anode, and a cathode chamber 390, for distributing dioxygen to the cathode.

[0205] The anode chamber further comprises an inlet orifice 400 for the supply of dihydrogen, which orifice is connected to the discharge opening 85 of the apparatus by means of a hollow conveyance tube 410.

[0206] The apparatus shown in FIG. 13 is identical to that described in FIG. 1, except that the pressure measurement unit 25 is disposed in the anode chamber 385 of the fuel cell. In another variant, not shown, the pressure measurement unit 25 can be disposed in the hollow tube 410.

[0207] Thus, during operation, the generation of dihydrogen by the apparatus is adapted as a function of the dihydrogen requirement of the fuel cell.

[0208] With respect to the method according to the invention, it comprises at least one cycle, preferably several cycles, made up of steps a) to c).

[0209] FIG. 14 shows the evolution of the gas pressure P.sub.g inside an enclosure of an apparatus according to the invention, as is particularly described in FIGS. 1 and 2, as a function of the time t for implementing the method. As can be seen, the gas pressure changes between minimum P.sub.g.sup.min and P.sub.g.sup.max maximum values, which correspond to the minimum and maximum regulation pressures, respectively. For example, during the first period 400 for implementing the method (between t=0 and t=4), the minimum regulation pressure equals 1.3 bar and the maximum regulation pressure equals 1.5 bar. Starting from t=4, in a second period 405 for implementing the method, the user modifies the maximum regulation pressure, by means of the regulation unit, to a value of 1.6 bar. Starting from t=9, in a third period 410 for implementing the method, the maximum and minimum regulation pressures are simultaneously modified, respectively increased to 1.7 bar and decreased to 1.1 bar. Thus, the average pressure during the first 400 and third 405 periods is identical, equal to 1.4 bar. For example, for an identical average pressure, an increase in the maximum regulation pressure and a decrease in the minimum regulation pressure results in a reduction in the number of opening/closing cycles of the catalytic system, which reduces the compressible fluid consumption and the energy consumption for generating the gas. A reduction in the amplitude around the average pressure, by decreasing the maximum regulation pressure and increasing the minimum regulation pressure enables better adaptation to the operating requirements of a fuel cell. It also allows the gas generation apparatus to respond more quickly and easily to peaks in the setpoint flow rate imposed by a fuel cell to which the apparatus is connected. Regulating the minimum and maximum regulation pressures thus allows the user of the device to adapt the gas generation to the specifics of the application for which the gas is intended.

EXAMPLES

[0210] The invention is illustrated by means of the following non-limiting examples.

Example 1

[0211] Gas is generated by means of an apparatus as shown in FIG. 1. To this end, the catalytic system comprises, inside the catalysis chamber, 1 gram of cobalt, and the internal space of the enclosure, with a capacity of 0.6 1, contains 0.5 1 of a sodium borohydride solution. The initial temperatures of the catalyst and of the liquid solution are both equal to 25 C.

[0212] The apparatus is connected to a fuel cell, which it supplies with generated dihydrogen.

[0213] The minimum regulation pressure is set to 1.4 bar and the maximum regulation pressure is set to 1.5 bar.

[0214] FIG. 15 shows the evolution of the gas pressure P.sub.g in the enclosure as a function of the time t for implementing the method.

[0215] At the instant t.sub.o=0, the catalytic system is placed in the open position. The gas generation begins and the generated gas setpoint flow rate is reached (value of 1,000 ml/min) from the first cycle for implementing the method. As can be seen in FIG. 15, the gas pressure Pg in the enclosure is, in the initial instants of the generation of dihydrogen, greater than 2 bar, whereas the maximum regulation pressure is 1.5 bar. This phenomenon is explained by the inventors as resulting from a catalytic chamber volume that is not optimized, which is too big compared to the volume of the catalyst. Over time, the hydride content of the solution decreases, such that the volume of solution captured in the catalysis chamber during each closure causes increasingly less gas to be generated. With the gas consumption by the fuel cell being constant, the gas pressure in the enclosure thus exceeds the maximum imposed regulation pressure less and less often. The generation of gas thus continues until the instantaneous amount of generated gas is less than the instantaneous amount of gas consumed by the fuel cell to which the apparatus is connected (instant t.sub.1=220 min), as shown in FIG. 15.

[0216] Thus, the mass hydrogen yield, defined as the ratio between the generated hydrogen mass and the total mass of solution of the method according to the invention, is 3.6%.

Comparative Example

[0217] Gas is generated by means of the enclosure of the device of the apparatus shown in FIG. 1. The catalytic system, in the form of a buoy disclosed in WO 2012/003112 A1, is used instead of the catalytic system according to the invention. The same amounts of cobalt and of sodium borohydride solution are used as in example 1.

[0218] FIG. 15 shows the evolution of the gas pressure P.sub.g.sup.comp in the enclosure as a function of the time t for implementing the method.

[0219] At the instant t.sub.o=0, the catalytic system is placed in the open position. The gas generation begins and the generated gas setpoint flow rate is immediately reached (value of 1,000 ml/min).

[0220] The generation of gas at the setpoint flow rate thus continues until the pressure in the enclosure reaches 1 bar at t.sub.2=110 min. From this instant, the pressure in the enclosure becomes equal to the atmospheric pressure. The apparatus of the prior art can no longer produce a sufficient amount of gas to guarantee the setpoint flow rate, since the concentration of reagents is too low in relation to the accessibility of the catalyst.

[0221] Thus, the mass yield of the method of the prior art is 1.8%.

Example 3

[0222] A device as described in FIG. 13 is provided, except that the pressure measurement unit 25 is provided to measure the gas pressure in the internal space, as shown in FIG. 1. The method is implemented under the following conditions. The desired setpoint flow rate, regulated by a flow control valve fixed on the discharge opening of the apparatus (not shown), is set to 160 ml/min. This flow rate control valve allows the gas consumption of a fuel cell to be simulated. The apparatus is disposed in a climatic enclosure, the temperature of which is 8 C. Before opening the catalytic system, the temperature of the hydride solution is 1 C. and the temperature of the catalyst is 0 C.

[0223] The evolution of the temperatures of the catalyst T.sub.e, of the aqueous hydride solution T.sub.sol contained in the enclosure, of the environment outside the apparatus T.sub.ext, as well as of the dihydrogen flow rate M.sub.H2 and the dihydrogen pressure P.sub.g in the enclosure as a function of the time for implementing the method, are shown in FIGS. 16 and 17.

[0224] At t.sub.o=0, the apparatus is controlled so that the command unit executes a regulation control mode as previously described. The catalytic system is open after a command to open the piston is sent to the command valve, with the gas pressure initially being less than the minimum regulation pressure. With the temperature of the catalyst and of the aqueous hydride solution both being less than 5 C., the catalyzed hydrolysis reaction exhibits slow kinetics, such that the generated dihydrogen flow rate is approximately 100 ml/min, less than the setpoint flow rate, throughout a first period 430, up to t=1.4 min.

[0225] During the period 430, the control unit analyzes, as control quantities, the generated dihydrogen flow rate M.sub.H2 and the temperature of the catalyst T.sub.c.

[0226] At t=1.4 min, the control unit sends a transmission, as a result of the analysis, to the effect that the flow rate is less than a setpoint flow rate set to 160 ml/min, and that the temperature of the liquid is less than a setpoint temperature set to 0 C. It then transmits a control signal intended for the command unit for implementing a cold control mode. Following the reception of the control signal, the command unit executes the cold control mode by firstly sending a closure command signal to the command valve in order to place the catalytic system in the closed position. Optionally, it can send a signal to the flow control valve to close the discharge opening in order to prevent dihydrogen from being discharged out of the enclosure. As a variant, a signal can be sent to the fuel cell so that said cell is paused during the execution of the cold control mode. The closure command signal is maintained throughout the periods referenced 435 and 440. A volume of aqueous hydride solution is thus contained in the catalysis chamber, isolated from the internal space of the enclosure. This volume of aqueous hydride solution reacts in contact with the catalyst, which leads to a generation of dihydrogen, which is discharged out of the catalytic chamber in the internal space. The dihydrogen pressure increases in the enclosure. With the hydrolysis of the aqueous hydride solution being exothermic, the temperature of the catalyst consequently increases during the periods 435 and 440 up to approximately 16 C. During the periods 435 and 440, according to the cold control mode, the control unit receives and analyzes the generated gas pressure and, optionally, the temperature of the catalyst, as quantities to be controlled. At the end of the period 440, the generated gas pressure is greater than a control parameter, namely the maximum regulation pressure of the regulation mode, set to 1.5 bar. The command unit then sends a command signal for opening the enclosure, at the start of the period 445, so that the dihydrogen is discharged and is, for example, consumed by a fuel cell PAC, thus reducing the dihydrogen pressure in the enclosure. The command unit can send, at the end of the period 445, a command signal for placing the catalytic system in the open position, as is described hereafter. For example, the transmission of the command signal for opening the enclosure can result from the reception of a signal originating from the fuel cell. During the period 445, the gas pressure decreases, with the flow control valve being open allowing the gas to escape from the enclosure. The command unit then analyzes the gas pressure and compares it to a second control parameter, which is, for example, less than the minimum pressure of the regulation mode. For example, the second control parameter is the atmospheric pressure. In the event that the gas pressure in the enclosure drops below the second control parameter, the command unit sends a closure command signal that is maintained, as during the periods 435 and 440, so as to once again heat up the catalyst. Otherwise, if the pressure increases after having reached the minimum regulation value, following the decomposition of the hydrides of the solution in contact with the catalyst, the control unit transmits a regulation mode control signal. The command unit ceases to execute the cold control mode, as is observed during the period 450.

[0227] When the dihydrogen pressure in the enclosure drops below the minimum regulation pressure, from t=2.75 min, during the period 450, the command unit sends a command signal to open the command valve. With the temperature of the catalyst having increased relative to the first period, reaching the setpoint flow rate is immediate and several cycles for opening/closing the catalytic system according to the regulation control mode are then implemented.

[0228] As is clearly apparent from the present description, the generation of gas, in particular of dihydrogen, by means of the apparatus according to the invention can be easily adapted as a function of the application for which the generated gas is intended. In particular, it allows efficient generation of dihydrogen to be initiated, which is reliable in an environment where the temperature is below 0 C., and allows the generated gas pressure profile to be adapted to the application.

[0229] Of course, the invention is not limited to the embodiments of the apparatus and of the device according to the invention, as well as to the modes for implementing the method that have been described and shown.