Hydrogen station

Abstract

Hydrogen Station This description relates to a hydrogen station (100) comprising a control circuit (123) configured to implement, prior to a step of disconnecting at least one hose (125) connecting a vehicle (127) to the station, a step of recycling hydrogen from said hose to a first tank (119) of the station. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Hydrogen station technical field

[0001] This description relates generally to hydrogen distribution systems, in particular hydrogen supply stations also called hydrogen distribution stations or, more simply, hydrogen stations. Previous technique

[0002] Hydrogen refueling stations for hydrogen vehicles have been proposed. When a hydrogen vehicle, for example a hydrogen car, is connected to a hydrogen refueling station, the station specifically fills an onboard hydrogen storage tank. The hydrogen in the tank is used, in particular, as propulsion power for the vehicle. For this purpose, the hydrogen is, for example, converted into electricity by a fuel cell powering an electric motor. When refueling its hydrogen tank, the vehicle is connected to the station by a hose. Before disconnecting the hose from the vehicle, the residual hydrogen under high pressure present in the hose is vented from the station through a vent.

[0003] Existing hydrogen stations have several drawbacks. In particular, venting residual hydrogen under high pressure from the vehicle's connection hose to the station outside the station causes unwanted noise and material loss. Summary of the invention

[0004] There is a need to mitigate all or part of the drawbacks of existing hydrogen stations. In particular, it would be desirable to reduce noise pollution and material losses prior to disconnecting the hose connecting a vehicle to the station.

[0005] For this purpose, one embodiment provides a hydrogen station comprising a control circuit configured to implement, prior to a step of disconnecting at least one connecting hose from a vehicle to the station, a step of recycling hydrogen from said hose to a first tank of the station.

[0006] One embodiment further provides a method for controlling a hydrogen station, the method comprising, prior to a step of disconnecting at least one connecting hose from a vehicle to the station, a step of recycling hydrogen from said hose to a first tank of the station.

[0007] According to one embodiment, the hydrogen transfer step includes an operation of opening a first valve of the station, the first valve connecting said hose to the first tank.

[0008] According to one embodiment, a step of evacuating, outside the station, a volume of residual hydrogen contained in said hose is implemented between the hydrogen transfer step and the step of disconnecting said hose.

[0009] According to one embodiment, the station further comprises a compression device having an inlet connected, by a second valve, to at least a second hydrogen supply tank for the station.

[0010] According to one embodiment, the first reservoir is connected to the inlet of the compression device.

[0011] According to one embodiment, a step of closing the second valve is implemented prior to the hydrogen transfer step.

[0012] According to one embodiment, the second valve is closed at a determined time based on an estimate of the filling time of a third hydrogen storage tank of the vehicle.

[0013] According to one embodiment, the filling time is estimated as a function of a hydrogen pressure in the third tank.

[0014] According to one embodiment, the first reservoir has a volume on the order of a few tens of litres, preferably between twenty and fifty litres. Brief description of the drawings

[0015] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments and implementations, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0016] [Fig.1] is a very simplified P&ID diagram of a hydrogen station according to one embodiment;

[0017] [Fig. 2] is a flowchart illustrating successive steps of a control method for the hydrogen station of [Fig. 1] according to an implementation method; and

[0018] [Fig.3] is a graph of the evolution, as a function of time, of a pressure in a hydrogen tank of the hydrogen station of [Fig.1] during the implementation of the control method of [Fig.2]. Description of the implementation methods

[0019] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments and implementation methods may have the same reference numerals and may have identical structural, dimensional and material properties.

[0020] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments and implementation methods have been shown and are detailed. In particular, the operations for refueling hydrogen vehicles from a hydrogen station have not been detailed, as the described embodiments and implementation methods are compatible with the usual operations for refueling hydrogen vehicles from a hydrogen station.

[0021] Unless otherwise specified, when referring to two elements connected between them, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or linked via one or more other elements.

[0022] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0023] Unless otherwise specified, the expressions "approximately", "about", " "Similarly" and "of the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0024] Fig. 1 is a very simplified P&ID (Piping and Instrumentation Diagram) of a hydrogen station 100 according to one embodiment.

[0025] In the example shown, the hydrogen station 100 includes a compression device 101 connecting nodes 103 and 105 of a hydrogen circuit. In this example, the compression device 101 has an inlet connected to node 103 and an outlet connected to node 105. The compression device 101 is intended to compress the hydrogen present at node 103 to node 105. During operation, the pressure at node 105, located downstream of the compression device 101, is strictly greater, for example, between two and thirty times greater, for example, about four times greater, than the pressure at node 103, located upstream of the compression device 101. The pressure increase caused by the compression device 101 is, for example, on the order of several tens of bars or several hundred bars.As an example, the compression device 101 includes a gas blower, for example a single-stage double-acting blower or a single-stage double-acting blower, connected to a network (not detailed in [Fig.1]) of compressed air or pressurized oil associated with a control system.

[0026] In the illustrated example, the compression device 101 of the hydrogen station 100 is supplied with hydrogen from a supply tank 107 connected to the node 103 by a supply valve 109. As an example, the supply tank 107 contains hydrogen at a pressure on the order of several tens or a few hundred bars, for example, between fifty and three hundred bars. The supply valve 109, when open, allows the circuit to be supplied with hydrogen from the supply tank 107 and, when closed, isolates the supply tank 107 from the hydrogen circuit of the station 100. [Fig. 1] illustrates an example in which the supply tank 107 is located outside the hydrogen station 100. However, this example is not limiting and the tank 107 can, alternatively, be located in the hydrogen station 100. Furthermore, although [Fig.[l] illustrates an example in which the compression device 101 is supplied with hydrogen from a single tank 107; however, this example is not limiting and the compression device 101 can, as an alternative, be supplied with hydrogen from several tanks 107.

[0027] In the example shown, the hydrogen station 100 further includes a hydrogen storage tank 111 connected to the node 105 by a storage valve 113. The tank 111 stores the hydrogen compressed by the compression device 101. The valve 113, when open, allows hydrogen to be transferred to or from the storage tank 111 and, when closed, isolates the storage tank 111 from the rest of the hydrogen circuit. During operation, the pressure of the storage tank 111 is strictly greater than the pressure of the supply tank 107. By way of example, the pressure inside the storage tank 111 is on the order of several hundred bar, for example, approximately nine hundred bar.

[0028] According to one embodiment, the hydrogen station 100 further comprises a hydrogen recycling loop 115, or hydrogen recirculation loop, connecting node 105 to node 103. The hydrogen recycling loop 115 includes a recycling valve 117 in series with a buffer tank 119. The recycling valve 117, in the open position, allows hydrogen to be transferred from node 105 to the buffer tank 119 and, in the closed position, isolates node 105 from the buffer tank 119. During operation, the pressure of the buffer tank 119 is strictly lower than the pressure of the storage tank 111. By way of example, the hydrogen contained in the buffer tank 119 has a pressure on the order of several tens or hundreds of bars, for example, between thirty and three hundred bars. The buffer tank 119, for example, has a volume of a few tens of liters, for example between twenty and fifty liters.

[0029] The hydrogen station 100 further includes, for example, a pressure sensor 121 (P) connected to node 103. The pressure at node 103 is, for example, substantially equal to the pressure of the buffer tank 119.

[0030] In the example shown, the hydrogen station 100 further includes a vent device connected to node 105. Although not detailed in [Fig. 1], a valve connects, for example, node 105 to the vent. In the open position, this valve allows the vent to discharge, outside the hydrogen station 100, a volume of residual hydrogen present downstream of the compression device 101. The storage valve 113 is preferably closed during the discharge of the residual hydrogen volume.

[0031] In the illustrated example, the hydrogen station 100 further includes a control system comprising a control circuit 123 (CMD), for example a programmable logic controller (PLC), enabling in particular the actuating, or controlling, of the valves 109, 113 and 117 and the receiving, from the pressure sensor 121, of information of the pressure P present at node 103. The programmable logic controller 123 can of course be connected to other sensors and / or actuators not detailed in [Fig. 1].

[0032] In the example shown in [Fig. 1], a flexible hose 125 connects a vehicle 127 to the station 100 to allow the hydrogen supply of the vehicle 127 from the station 100. Although this has not been detailed in [Fig. 1] in order to avoid cluttering the drawing, several vehicles 127 can be simultaneously connected by flexible hoses 125 to the hydrogen station 100. In this case, the station 100 includes, for example, several recycling valves 117 and a single buffer tank 119. By way of example, the vehicle 127 is a hydrogen car. Although not detailed in [Fig.l], the end of the flexible hose 125 located on the vehicle 127 side may include a hydrogen dispensing gun intended to be connected to a filling port of a tank of the vehicle 127 (not detailed in [Fig.l]) to allow its supply of hydrogen from station 100.

[0033] Although not detailed in [Fig.1], the hydrogen station 100 may further include other elements or circuits symbolized by a single functional block 129 (FCT).

[0034] Figure 2 is a flowchart illustrating successive steps of a control process 200 for the hydrogen station 100 of Figure 1 according to one implementation method. The control circuit 123 of the hydrogen station 100 is, for example, configured to implement the steps of process 200.

[0035] The process 200 includes a step 201 of connecting the vehicle 127 to the hydrogen station 100. During this step, a user of the vehicle 127 connects, for example, the hose 125 to his vehicle 127 to start filling a hydrogen tank of the vehicle 127 from the hydrogen station 100. At this stage, the valves 109, 113 and 117 are in the closed position and the pressure at node 105 is, for example, substantially equal to atmospheric pressure.

[0036] In a further step 203, subsequent to step 201, the refueling time of the hydrogen tank of vehicle 127 is estimated. For example, the refueling time of the tank of vehicle 127 is estimated from a measurement of the hydrogen pressure inside this tank, for example a measurement taken by a pressure sensor (not shown) connected to the tank of vehicle 127, and from a measurement of the hydrogen temperature inside this tank, for example a measurement taken by a temperature sensor (not shown) connected to the tank of vehicle 127. Alternatively, the refueling time of the tank of vehicle 127 is predetermined.

[0037] Once the estimated filling time is determined, the pilot-operated valves 109 and 113 are opened, the recirculation valve 117 is kept closed, and the compression device 101 is activated. Opening the supply valve 109 leads to the filling of the buffer tank 119 with hydrogen. The pressure of the buffer tank 119 is then, at this stage, substantially equal to the pressure of the supply tank 107. Under the action of the compression device 101, supplied with hydrogen from the tank 107, the storage tank 111 and the vehicle tank 127 are filled with pressurized hydrogen.

[0038] In a subsequent step 205, after step 203, the supply valve 109 is closed. This isolates the supply tank 107 from the hydrogen circuit of the hydrogen station 100, thus interrupting the supply of hydrogen to the compressor 101 from the supply tank 107. Once the supply valve 109 is closed, the compressor 101 continues to be supplied with hydrogen from the buffer tank 119. As the hydrogen from the buffer tank 119 is compressed by the compressor 101, the pressure in the buffer tank 119, and therefore the pressure P measured by the pressure sensor 121, decreases.

[0039] In a further step 207, subsequent to step 205, the recycling valve 117 of the loop 115 is opened. Prior to the opening of the recycling valve 117, the compression device 101 is stopped and the pilot valve 113 is closed to isolate the tank 111 from the rest of the hydrogen circuit. Due to the pressure difference between nodes 105 and 103—the pressure at node 105 being, at this stage, strictly higher than the pressure at node 103—opening the recycling valve 117 causes a transfer, or recycling, of the majority of the hydrogen present in the portion of the hydrogen circuit located downstream of the compression device 101, particularly in hose 125, to the buffer tank 119. This allows the hydrogen pressure at node 105 to be reduced, specifically the pressure and volume of hydrogen contained in hose 125. A safety check is, for example, implemented prior to opening the valve. recycling 117, in order to ensure that the pressure P at node 103 is low enough for the buffer tank 119 to accommodate the hydrogen contained in the part of the circuit located downstream of the compression device 101.

[0040] After a period allowing pressure equilibrium to be reached, for example after a few seconds, the recirculation valve 117 is closed.

[0041] In a further step 209, subsequent to step 207, node 105 is vented. This causes the residual hydrogen contained in the part of the circuit located downstream of the compression device 101 to be vented or purged to the outside of station 100. In particular, hydrogen contained in hose 125 is vented to the outside of hydrogen station 100 during this step.

[0042] In another step 211, subsequent to step 209, the hose 125 is disconnected from the vehicle 127.

[0043] The implementation of process 200 has the advantage of significantly reducing, for example by a factor of between twenty and thirty, for example approximately 25, the hydrogen pressure at node 105 prior to venting before disconnecting the hose 125 connecting the vehicle 127 to the station 100. For example, the pressure is reduced from approximately 850 bar to approximately 30 bar. This advantageously reduces noise and material loss prior to disconnecting the hose 125. The implementation of process 200 allows, for example, the collection of approximately 80 to 90% of the hydrogen contained in the circuit downstream of the compression device 101 in the buffer tank 119.

[0044] Although [Fig. 2] illustrates an example of a control method in which the compression device 101 is in operation during steps 203 and 205, this example is not limiting and the compression device 101 may, alternatively, be kept in a standstill during these steps. This alternative mode of operation is within the grasp of a person skilled in the art, based on the information in this description.

[0045] Figure 3 is a graph showing the evolution, as a function of time t, of a pressure P in the buffer tank 119 of the hydrogen station 100 of Figure 1 during the implementation of the control method 200 of Figure 2. The graph in Figure 3 includes, in particular, two curves 301 and 303 illustrating two examples of the operation of the hydrogen station 100.

[0046] In the operating example of station 100 illustrated by curve 301, the tank of vehicle 127 is, at time t0, being filled. At time t0, the pressure P is equal to a high value PL. The high value PL is, for example, approximately equal to the pressure of the supply tank 107. As an example, the high value PL is between fifty and three hundred bar.

[0047] At time t1, later than time t0, the supply valve 109 is closed. At time t1, the compression device 101 is maintained in operation but ceases to be supplied from the supply tank 107. This causes a drop in pressure P.

[0048] Between time t1 and a time t2, subsequent to time t1, the pressure P decreases from the high value PI to a low value P2 strictly lower than the high value PI, the value P2 being the lowest possible. For example, the low value P2 is between twenty and fifty bars.

[0049] At time t3, later than time t2, the recirculation valve 117 is opened. Between times t2 and t3, the pressure P remains substantially constant and equal to the low value P2. The opening of the recirculation valve 117 causes a rise in pressure P from the low value P2 to an intermediate value P3 strictly lower than the high value P1 and strictly higher than the low value P2. The rise in pressure P from the low value P2 to the intermediate value P3 is caused by the transfer, into the buffer tank 119, of some of the hydrogen contained downstream of the compression device 101.

[0050] In the illustrated example, the intermediate value P3 and the low value P2 are separated by a pressure difference AP. The maximum achievable pressure difference AP is taken into account, for example, when sizing the buffer tank 119. The buffer tank 119 is designed, for example, to withstand a pressure increase AP equivalent to a complete purge of the section of the circuit located downstream of the compression device 101, or several purges if the station 100 includes several hoses 125. As an example, the buffer tank 119 is capable of receiving a volume of hydrogen of approximately 0.1 L at a pressure of approximately 900 bar. If the tank 119 has a volume of approximately 20 L, the pressure increase AP caused at time t3 by the opening of the recirculation valve 117 is approximately 4 bar.

[0051] In the operating example of station 100 illustrated by curve 301, the pressure P is maintained at the low value P2 for a duration D separating times t2 and t3. However, the hydrogen station 100 exhibits a higher efficiency when the pressure P is high, for example equal to PI, compared to the case where the pressure P is low, for example equal to P2. It is therefore desirable to reduce the duration D during which the pressure is equal to P2 as much as possible in order to optimize the efficiency of the hydrogen station 100.

[0052] Curve 303 illustrates an example of operation of station 100 in which the duration D is less than that of the example of operation illustrated by curve 301. The example illustrated by curve 303 corresponds more precisely to an optimal, or ideal, operating case in which the duration D is substantially zero.

[0053] In the example illustrated by curve 303, at a time t'1, later than time tl and analogous to time tl, the supply valve 109 is closed. This causes a drop in pressure P.

[0054] Between time t'1 and time t3, later than time t'1, the pressure P decreases from the high value PI to a low value P2 strictly lower than the high value PI.

[0055] At time t3, the recirculation valve 117 is open. This causes, as previously explained in relation to curve 301, an increase in pressure P from the low value P2 to the intermediate value P3.

[0056] The closing time of the supply valve 109 (time tl or t'1, in the examples shown) is, for example, determined as a function of the time it takes to fill the tank of the vehicle 127 and the time it takes for the pressure P to decrease from the high value PI to the low value P2, in order to minimize the time D. The time it takes to fill the tank of the vehicle 127 is, for example, estimated by a pressure measurement and / or a temperature measurement of this tank after connection of the hose 125 and before starting the filling operations.

[0057] Various embodiments, implementation methods, and variants have been described. Those skilled in the art will understand that certain features of these various embodiments, implementation methods, and variants could be combined, and other variants will become apparent to those skilled in the art.

[0058] In particular, a person skilled in the art is able, based on the indications in this description, to adapt the embodiments described to the case where several vehicles 127 are connected to the station 100 by several hoses 125 and where the station 100 comprises a single buffer tank 119. In this case, the process described above in relation to [Fig. 2] is, for example, implemented sequentially for each of the hoses 125. By way of example, the implementation of this process is, for each hose 125, initiated by the estimated completion of refueling of the vehicle 127 connected to that hose 125, the completion of refueling of the tanks of the different vehicles 127 connected to the station 100 not being simultaneous. In particular, the hydrogen is recycled from each of the hoses, before their disconnection, to the buffer tank 119 of the station 100.For this purpose, several valves 117 respectively connect the different flexible hoses 125 to the buffer tank 119.

[0059] Finally, the practical implementation of the embodiments, implementation methods and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Hydrogen station (100) comprising a control circuit (123) configured to implement, prior to a step (211) of disconnecting at least one hose (125) connecting a vehicle (127) to the station, a step (207) of recycling hydrogen from said hose to a first tank (119) of the station.

2. Method of controlling (200) a hydrogen station (100) comprising, prior to a step (211) of disconnecting at least one hose (125) connecting a vehicle (127) to the station, a step (207) of recycling hydrogen from said hose to a first tank (119) of the station.

3. Station (100) according to claim 1, or method (200) according to claim 2, wherein or wherein the hydrogen transfer step includes an operation of opening a first valve (117) of the station, the first valve connecting said hose (125) to the first tank (119).

4. Station (100) according to claim 1 or 3, or method (200) according to claim 2 or 3, wherein or wherein a step (209) of evacuating, outside the station, a volume of residual hydrogen contained in said hose (125) is implemented between the hydrogen transfer step (207) and the disconnection step (211) of said hose.

5. Station (100) according to claim 1, 3 or 4, or method (200) according to any one of claims 2 to 4, wherein or wherein the station (100) further comprises a compression device (101) having an inlet connected, by a second valve (109), to at least a second hydrogen supply tank (107) for the station.

6. Station (100) or method (200) according to claim 5, in which or which the first tank is connected to the inlet of the compression device (101).

7. Station (100) or method (200) according to claim 5 or 6, wherein or in which a step (205) of closing the second valve is implemented prior to the hydrogen transfer step (207).

8. Station (100) or method (200) according to claim 7, wherein or in which the second valve (109) is closed at a specified time based on an estimate (203) of the filling time of a third hydrogen storage tank of the vehicle (127).

9. Station (100) or method (200) according to claim 8, in which or wherein the filling time is estimated as a function of hydrogen pressure in the third tank.

10. Station (100) according to any one of claims 1, 3 to 9, or method (200) according to any one of claims 2 to 9, in which or wherein the first reservoir (119) has a volume on the order of a few tens of liters, preferably between twenty and fifty liters.