Method for determining the initial pressure in a pressurized gas tank to be filled from a distribution station.

Abstract

Method (200) for determining the initial pressure of a pressurized gas tank (4) to be filled from a dispensing station (100), the dispensing station (100) comprising a filling line (TL) having in series a pressurized gas source (1), a heat exchanger (2), and a distributor (3), the dispensing station (100) also comprising a branch line (L4) from the filling line (TL) at the heat exchanger (2), the method (200) comprising the following steps: a step (S1) of transferring a gas flow from the gas source (1) or the heat exchanger (2) to the distributor (3) via the branch line (L4), a step (S4) of recording an initial pressure in the tank (4) to be filled as a function of a pressure measured on the filling line (TL). Abstract figure: Fig. 1

Description

Title of the invention: Method for determining the initial pressure in a pressurized gas tank to be filled from a distribution station.

[0001] The invention relates to a method for determining the initial pressure in a pressurized gas tank to be filled from a distribution station. The pressurized gas may be hydrogen.

[0002] Before filling a pressurized gas tank from a distribution station, it is necessary to know the initial residual gas pressure in the tank to be filled. This initial pressure data allows the filling parameters to be adjusted and, in particular, prevents overfilling or overheating, which can affect the integrity of the tank and endanger the user.

[0003] To determine the initial pressure in a tank to be filled, various methods exist. Two of them are described in document US2016010799A in relation to a distribution station comprising a transfer line which connects a pressurized gas storage tank, a heat exchanger and a distributor.

[0004] In particular, the filling line is equipped with a flow meter and a pressure controller upstream of the heat exchanger. Furthermore, the filling line is equipped with a control valve downstream of the heat exchanger. This valve can be bypassed via a line connecting to the filling line.

[0005] Thus, to determine the initial gas pressure in the tank to be filled, a first method involves sending a gas flow from the storage tank to the distributor via the flow meter, the pressure controller, and the heat exchanger of the filling line. According to this first method, the opening of the pressure controller is progressively adjusted to increase the pressure in the filling line. The pressure at which a flow rate is recorded by the flow meter represents the initial pressure of the tank.

[0006] This first method therefore requires a pressure controller and a valve that are compatible with very low flow rates. Furthermore, the valve must also be configured to allow higher flow rates.

[0007] However, it is difficult to find a valve capable of handling large flow rates while also being able to finely regulate low flow rates at low pressure. Hence, a limitation of the first method.

[0008] A second method includes a step of sending a gas flow from the storage to the distributor via the heat exchanger and the line of diversion. To do this, the valve located on the diversion line is opened initially and then closed after a few seconds.

[0009] During valve opening, a pressure rise and fall cycle is observed at the heat exchanger. Such a cycle is detrimental to the lifespan of the heat exchanger.

[0010] One object of the invention is to remedy at least in part the disadvantages listed above and to propose a method which is simple to implement.

[0011] To this end, according to a first aspect, the invention relates to a method for determining the initial pressure of a pressurized gas tank, to be filled from a distribution station.

[0012] In particular, the distribution station includes a filling line comprising in series a pressurized gas source, a heat exchanger, and a distributor. The distribution station also includes a branch line from the filling line at the heat exchanger.

[0013] The method includes the following steps: a step of transferring a gas flow from the source or from the exchanger to the distributor via the bypass line, and a step of recording an initial pressure in the tank to be filled as a function of a pressure measured on the filling line.

[0014] Furthermore, embodiments of the invention may include one or more of the following features: - the branch line has a first end connected to the filling line at a first junction point located upstream of the heat exchanger, and a second end connected to the filling line at a second junction point located downstream of the heat exchanger, - The bypass line includes a flow and / or pressure regulation system, - The flow and / or pressure regulation system includes a regulating valve and possibly a restriction zone preferably located downstream of the regulating valve. - the branch line is formed by a conduit of constant cross-section, - the constriction zone includes a calibrated orifice arranged in the conduit, - the branch line is formed by a conduit comprising a portion central section of reduced cross-section and two end portions with a cross-section greater than that of the central portion, - the central portion of the duct forms the constriction zone, - The filling line includes a first circuit connecting the gas source to an inlet of the heat exchanger, - The first circuit is equipped with a first valve, a flow meter, a pressure controller and a first pressure sensor, - The first valve and the flow meter are positioned upstream of the first junction point. - The pressure controller and the first pressure sensor are located downstream of the first junction point. - The filling line includes a second circuit connecting an outlet of the heat exchanger to the distributor, - the second circuit is equipped with a second valve, a second pressure sensor, and a temperature sensor, - the second valve is located upstream of the second junction point, - The temperature sensor and the second pressure sensor are located downstream of the second junction point. - The method includes a step of monitoring an increase in gas pressure in the filling line up to a first value, - The method includes a step of monitoring a decrease in pressure in the filling line down to a second value, the second value being lower than the first value, - The initial pressure measurement step in the tank to be filled includes an operation to identify the initial pressure at the second value measured in the filling line, - the method includes a step of balancing a pressure in the heat exchanger with a pressure in the tank to be filled.

[0015] According to a second aspect, the invention relates to a distribution station for a gas under pressure.

[0016] The distribution station includes a filling line comprising in series a pressurized gas source, a heat exchanger, and a distributor. In addition, the distribution station includes a branch line from the filling line at the heat exchanger.

[0017] According to this second aspect of the invention, the distribution station comprises an electronic device configured to control the transfer of a gas flow from the gas source or heat exchanger to the distributor via the bypass line. The electronic device is also configured to determine an initial pressure in the tank to be filled based on a pressure measured on the filling line.

[0018] Advantageously, the electronic device is also configured to calculate a final pressure in the tank as a function of the initial pressure.

[0019] Other features and advantages will become apparent upon reading the following description, made with reference to the following figures in which:

[0020] [Fig-1] is a schematic view illustrating a gas distribution station under pressure according to the invention, the station comprising a filling line connecting a gas source, a heat exchanger and a distributor, the station also comprising a bypass line from the filling line at the heat exchanger.

[0021] [Fig.2] illustrates steps of a method according to the invention for determining the initial pressure in a tank to be filled, from the distribution station illustrated in [Fig.1].

[0022] [Fig.3] illustrates a pressure evolution in the heat exchanger during the determination, according to a prior art method, of the initial pressure in a tank to be filled.

[0023] [Fig.4] illustrates a change in pressure in the heat exchanger during the determination, according to the method of the invention, of the initial pressure in a tank to be filled.

[0024] Fig. 1 illustrates a pressurized gas distribution station 100 according to the invention.

[0025] The distribution station 100 includes a filling line TL comprising in series a source 1 of pressurized gas, a heat exchanger 2, and a distributor 3 intended to receive a tank 4 to be filled.

[0026] In more detail, the filling line TL includes a first circuit L1 connecting the gas source 1 to an inlet of the heat exchanger 2, and a second circuit L2 connecting an outlet of the heat exchanger 2 to the distributor 3.

[0027] In particular, the first circuit L1 is provided with a first valve XVI, a flow meter FE1, a pressure controller PCVI, and a first pressure sensor PT1. The pressure controller PCV1 is configured to regulate the outlet pressure of the distributor 3 and the pressure of the heat exchanger 2.

[0028] The second circuit L2 is provided with a second XV2 valve, a second PT2 pressure sensor, and a TT2 temperature sensor. The second XV2 valve is configured to fluidly connect the heat exchanger 2 to the tank 4 to be filled. Furthermore, the second XV2 valve is configured to balance the pressure of the heat exchanger 2 with the pressure of the tank 4 to be filled.

[0029] The distribution station 100 may also include a pressurized gas storage tank 5 connected to the filling line TL by a third circuit L3. In particular, the third circuit L3 is connected to the first circuit L1 upstream of the first valve XVI.

[0030] The distribution station 100 also includes an L4 branch line from the TL filling line at the heat exchanger 2, and an L5 purge line from the TL filling line.

[0031] In particular, the L4 branch line has a first end connected to the TL filling line at a first junction point JP1 located upstream of the heat exchanger 2. The L4 branch line also has a second end connected to the TL filling line at a second junction point JP2 located downstream of the heat exchanger 2.

[0032] Furthermore, the L4 bypass line includes a flow and / or pressure control system for the gas flowing through it. This flow and / or pressure control system includes a control valve XV3. This control system may also include a restriction zone FO. The restriction zone FO is located downstream of the control valve XV3.

[0033] Finally, the L4 branch line can be formed from a conduit of constant cross-section. In this case, the FO restriction zone can be constituted by a calibrated orifice arranged in the conduit. Alternatively, the L4 branch line can be formed from a conduit comprising a central portion of reduced cross-section and two end portions with a cross-section larger than that of the central portion. In this case, the central portion with reduced cross-section forms the FO restriction zone.

[0034] It should be noted that the first valve XV1 and the flow meter FE1 of the first circuit L1 are located upstream of the first junction point JP1. The pressure controller PCV1 and the first pressure sensor PT1 of the first circuit L1 are located downstream of the first junction point JP1.

[0035] It should also be noted that the second valve XV2 of the second circuit L2 is located upstream of the second junction point JP2. The temperature sensor TT2 of the second circuit L2 is located downstream of the second junction point JP2.

[0036] The purge line L5 is connected to the second circuit L2 at a third junction point JP3. In the illustrated example, the third junction point JP3 is located between the second valve XV2 and the temperature sensor TT2. Furthermore, in the illustrated example, the purge line L5 carries the second pressure sensor PT2.

[0037] According to a first aspect of the invention, the distribution station 100 comprises a PLC electronic unit configured to control the transfer of a gas flow from the gas source, or the tank 5, or the heat exchanger 2 to the distributor 3 via the bypass line L4. The PLC electronic unit is also configured to determine an initial pressure in the tank 4 to be filled based on a pressure measured by the second pressure sensor PT2.

[0038] Advantageously, the PLC electronic unit is configured to calculate a final pressure in the tank 4 as a function of the initial pressure.

[0039] To determine the initial pressure in a tank 4 to be filled from a distribution station 100 described above, the invention introduces a method 200 described below.

[0040] Method 200 includes a step SI of transferring a gas flow from the gas source 1, or the storage tank 5, or the heat exchanger 2 to the distributor 3 via the bypass line L4. Method 200 also includes a step S4 of recording the initial pressure in the tank 4 to be filled based on the pressure recorded in the filling line TL.

[0041] In particular, transferring a gas flow from the heat exchanger 2 to the distributor 3 via the bypass line L4 allows the heat exchanger 2 to be discharged of some of the gas it contains. Furthermore, such a transfer helps prevent a surge in the tank 4 after its connection to the distributor 3.

[0042] The risk of a sudden surge at the level of the tank 4 to be filled exists in particular when the pressure of this tank 4 before its connection to the distributor 3 is lower than that of the heat exchanger 2.

[0043] It should be noted that the transfer of a gas flow from the heat exchanger 2 to the distributor 3 via the bypass line L4 is controlled by the pressure controller PCV1.

[0044] Advantageously, method 200 may include a step S2 of monitoring an increase in gas pressure in the filling line TL up to a first value Pmax. Similarly, method 200 may include a step S3 of monitoring a decrease in pressure in the filling line TL from the first value Pmax down to a second value Ptank.

[0045] The second Ptank value is lower than the first Pmax value. Furthermore, the second Ptank value indicates the initial pressure in the tank 4 to be filled.

[0046] Advantageously, the S2 step of monitoring the increase in pressure and the S3 step of monitoring the decrease in pressure in the TL filling line are executed using data provided by the second PT2 pressure sensor positioned on the second circuitry L2.

[0047] Advantageously, method 200 may include a step S5 for balancing the pressure of the heat exchanger 2 with the pressure of the tank 4 to be filled. To do this, the second valve XV2 of the second circuit L2 is opened.

[0048] After the balancing step S5, a proper filling step can take place. As mentioned above, the PCV1 pressure controller regulates the outlet pressure of the distributor 3 during this filling step.

[0049] At the end of the filling step, and to prevent thermal expansion in the heat exchanger 2, method 200 may include a conditioning step for the heat exchanger 2. This is a step during which the pressure in the heat exchanger 2 is lowered to a predefined threshold value, for example 500 bar, before a new cycle of steps SI - S4.

[0050] By passing the gas flow through the bypass line L4 of the heat exchanger 2 to determine the initial pressure in a tank 4 to be filled, the method 200 according to the invention prevents a pressure rise and fall cycle in this heat exchanger 2. The method thus prevents fatigue of the heat exchanger 2 material associated with such a pressure rise and fall cycle.

[0051] Figures 3 and 4 each show the pressure evolution in the heat exchanger 2 during a flow transfer from the gas source 1 or the storage tank 5 to the distributor 3. In Figure 3, the flow passes through the heat exchanger 2. In Figure 4, the flow bypasses the heat exchanger 2 via the bypass line L4.

[0052] In both cases, the evolution of the pressure in the heat exchanger 2 is recorded during the steps SI - S4 of determining the initial pressure in the tank 4, but also during the step S6 of filling the tank 4 itself, and during the conditioning step of the heat exchanger 2.

[0053] It can be seen that in the first case illustrated in [Fig. 3], the pressure in heat exchanger 2 increases and then stabilizes during steps S1–S4 before decreasing during the balancing step S5. In contrast, in the second case illustrated in [Fig. 4], the pressure in heat exchanger 2 remains stable during steps S1–S4. This stable evolution during steps S1–S4 is made possible by bypassing heat exchanger 2.

Claims

Demands

1. Method (200) for determining the initial pressure of a pressurized gas tank (4) to be filled from a distribution station (100), the distribution station (100) comprising a filling line (TL) having in series a pressurized gas source (1), a heat exchanger (2) and a distributor (3), the distribution station (100) also comprising a bypass line (L4) from the filling line (TL) at the heat exchanger (2), the method (200) comprising the following steps: a step (S1) of transferring a gas flow from the gas source (1) or the heat exchanger (2) to the distributor (3) via the bypass line (L4), a step (S4) of recording an initial pressure in the tank (4) to be filled as a function of a pressure measured on the filling line (TL).

2. Method (200) according to the preceding claim, comprising a step (S2) of monitoring an increase in the gas pressure in the filling line (TL) up to a first value (Pmax), and a step (S3) of monitoring a decrease in the pressure in the filling line (TL) up to a second value (Ptank), the second value (Ptank) being less than the first value (Pmax).

3. Method (200) according to the preceding claim, wherein the step (S2) of recording the initial pressure in the tank (4) to be filled includes an operation of identifying the initial pressure at the second value (Ptank) measured in the filling line (TL).

4. Method (200) according to any one of the preceding claims, comprising a step (S5) of balancing a pressure in the heat exchanger (2) with a pressure in the tank (4) to be filled.

5. Pressurized gas distribution station (100), comprising a filling line (TL) having in series a pressurized gas source (1), a heat exchanger (2), and a distributor (3), the distribution station (100) also comprising a branch line (L4) of the filling line (TL) at the heat exchanger (2), characterized in that it comprises an electronic device (PLC) configured to control a transfer of a gas flow from the gas source (1) or heat exchanger (2) to the distributor (3) via the bypass line (L4), the electronic device (PLC) also being configured to determine an initial pressure in the tank (4) to be filled as a function of a pressure measured on the filling line (TL).

6. Station (100) according to the preceding claim, wherein the electronic component (PLC) is also configured to calculate a final pressure in the tank (4) as a function of the initial pressure.

7. Station (100) according to any one of claims 5 or 6, wherein the bypass line (L4) has a first end connected to the filling line (TL) at a first junction point (JP1) located upstream of the heat exchanger (2), and a second end connected to the filling line (TL) at a second junction point (JP2) located downstream of the heat exchanger (2).

8. Station (100) according to any one of claims 5 to 7, wherein the bypass line (L4) includes a gas flow and / or pressure regulation system.

9. Station (100) according to the preceding claim, wherein the flow and / or pressure control system includes a control valve (XV3) and optionally a restriction zone (FO) located preferably downstream of the control valve (XV3).

10. Station (100) according to the preceding claim, wherein the branch line (L4) is formed of a conduit of constant cross-section, the necking zone (FO) comprising a calibrated orifice arranged in the conduit.

11. Station (100) according to claim 9, wherein the branch line (L4) is formed of a conduit having a central portion of reduced cross-section and two end portions of cross-section greater than a cross-section of the central portion, the central portion forming the (FO) necking zone.

12. Station (100) according to any one of claims 5 to 11, wherein the filling line (TL) comprises a first circuitry (L1) connecting the gas source (1) to an inlet of the heat exchanger (2), the first circuitry (L1) being provided of a first valve (XVI), a flow meter (FE1), a pressure controller (PCV1) and a first pressure sensor (PT1).

13. Station (100) according to the preceding claim taken in its connection with claim 7, wherein the first valve (XVI) and the flowmeter (FE1) are arranged upstream of the first junction point (JP1), the pressure controller (PCV1) and the first pressure sensor (PT1) being located downstream of the first junction point (JP1).

14. Station (100) according to any one of claims 5 to 13, wherein the filling line (TL) comprises a second circuitry (L2) connecting an outlet of the heat exchanger (2) to the distributor (3), the second circuitry (L2) being provided with a second valve (XV2), a second pressure sensor (PT2), and / or a temperature sensor (TT2).

15. Station (100) according to the preceding claim taken in its connection with claim 7, wherein the second valve (XV2) is disposed upstream of the second junction point (JP2), the temperature sensor (TT2) and the second pressure sensor (PT2) being disposed downstream of the second junction point (JP2).

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