JP5707043B2 - Pressurization method of liquefied hydrogen container in mobile hydrogen station - Google Patents

Description

  The present invention relates to a method for pressurizing a liquefied hydrogen container, and more particularly to a method for pressurizing a mobile liquefied hydrogen container.

In order to expand the use of hydrogen energy, there are two different types of mobile hydrogen stations: a compressed hydrogen type that stores hydrogen in the form of high-pressure gas of several tens of MPa, and a liquefied hydrogen type that stores hydrogen in the form of liquefied hydrogen. Development is ongoing. Among them, the type using liquid hydrogen, as compared to the type using compressed hydrogen, is large and a high degree of expectation for future mobile hydrogen station hydrogen amount that can be moved in per.

  A mobile hydrogen station of the type using liquefied hydrogen has a large amount of hydrogen that can be moved at one time as described above, and is highly efficient in that respect. However, when filling hydrogen into a fuel cell vehicle or the like, In this case, it is necessary to cool (precool) the piping and the booster pump in advance, and it takes a long time for filling, and the vaporized gas (vent gas) generated at the time of cooling is released to the atmosphere. There is a problem of end.

  The present invention has been made paying attention to such points, and liquefaction that can reduce the hydrogen gas loss while shortening the filling preparation time at the time of filling the hydrogen gas using liquefied hydrogen. It aims at providing the pressurization method of a hydrogen container.

Such Kan seen present invention in that the liquid hydrogen liquefied hydrogen pressure pump derived from liquefied hydrogen storage tank, through the vaporizer, when the hydrogen supply by the mobile hydrogen station which supplies a hydrogen gas receiving vessel,
Before starting the liquefied hydrogen pressure pump, the liquefied hydrogen lead-out passage that connects the liquefied hydrogen storage tank and the liquefied hydrogen pressure feed pump and the liquefied hydrogen pressure feed pump are cooled by liquefied hydrogen and the vaporized gas is vented to the vent gas discharge passage, A precooling step of returning the pressure to the liquefied hydrogen storage tank by returning to the liquefied hydrogen storage tank via the communication path and the pressurizing supply path;
The gas vaporized in the vaporizer at the start of hydrogen supply is returned to the liquefied hydrogen storage tank via the bypass path, vent gas discharge path, communication path, and pressurization supply path, and then returned to the liquefied hydrogen storage tank. A rapid pressurizing step to pressurize
A supplementary pressurization step of supplying hydrogen gas to the liquefied hydrogen storage tank from the pressure accumulator through the pressurization supply path to further pressurize the liquefied hydrogen storage tank;
It has the pressurization process comprised so that the inside of a liquefied hydrogen storage tank might be pressurized by this.

In the present invention, before starting the liquefied hydrogen pump, the liquefied hydrogen lead-out path and the liquefied hydrogen pressurizing pump that communicate between the liquefied hydrogen storage tank and the liquefied hydrogen pump are cooled by liquefied hydrogen (precool). In addition, by returning the low-temperature hydrogen gas vaporized by the precooling of this liquefied hydrogen pump to the liquefied hydrogen storage tank, the gas used for the precool can be used effectively, and the liquefied hydrogen pump and liquefied hydrogen can be used. The liquefied hydrogen lead-out path to the pressure pump can be lowered in a short time, and the precooling time can be shortened. In addition, by returning the gas vaporized in the vaporizer to the liquefied hydrogen storage tank, a large amount of the vaporized gas can be supplied to the liquefied gas storage tank by returning it to the liquefied hydrogen storage tank. Can be pressurized. Furthermore, by supplying hydrogen gas from the pressure accumulator to the liquefied hydrogen storage tank, even if rapid pressurization alone may cause the internal pressure of the liquefied water storage tank to be insufficient, the pressure can be quickly increased to the required pressure.

It is the schematic which shows an example of a liquefied hydrogen container installation. It is a flowchart which shows the procedure of the preparation work 1 at the time of liquefied hydrogen filling. It is a flowchart which shows the procedure of the preparation work 2 at the time of liquefied hydrogen filling.

  In this liquefied hydrogen container facility, the liquefied hydrogen storage tank (1) storing the liquefied hydrogen is connected to the suction port of the liquefied hydrogen pressure pump (2) through the liquefied hydrogen lead-out path (3), and the liquefied hydrogen pressure pump is connected. The liquefied hydrogen pressure feed path (4) led out from the discharge port of (2) is connected to the vaporizer (5), and the hydrogen gas vaporized by the vaporizer (5) is connected to the fuel cell vehicle via the flow rate controller (6). A hydrogen gas supply passage (8) is connected to a hydrogen gas receiving vessel (7) such as a hydrogen gas supply passage (8), and a pressurized gas supply passage (10) led from a pressure accumulator (9) is connected to a liquefied hydrogen storage tank (1). It is.

  Then, the bypass gas passage (12) led out from the vaporizer (5) is joined to the vent gas discharge passage (11) branched and led out from the liquefied hydrogen pressure feed passage (4), and the vent gas discharge passage (11) downstream from the joining portion. And a pressurizing gas supply path (10) are connected in communication by a communication path (13).

  The first flow path opening / closing valve (V1) is closer to the pressure accumulator (9) side than the connection point with the communication path (13) of the pressurizing gas supply path (10), and the second flow path opening / closing is connected to the communication path (13). The valve (V2) is located downstream of the connection point with the communication path (13) and the third gas passage opening / closing valve (V3) is upstream of the connection point with the communication path (13). A fourth passage opening / closing valve (V4) is attached to the vent gas discharge passage (11) on the side, and a fifth passage opening / closing valve (V5) is attached to the bypass passage (12).

  Each of these flow path opening / closing valves (V1 to V5) has an initial state for releasing the vaporized gas in the liquefied hydrogen storage tank (1), and a precool for cooling the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure pump (2). Stage, rapid pressurization stage to rapidly pressurize the inside of the liquefied hydrogen storage tank (1), additional pressure pressurization stage to actually pressurize the pressure in the liquefied hydrogen storage tank (1) to the filling work pressure, actually the liquefied hydrogen storage tank In the filling state in which the liquefied hydrogen stored in (1) is gasified and transferred to the hydrogen gas receiving container (7) and in the standby state, switching control is performed as described below.

  In the initial state, the second flow path opening / closing valve (V2) and the third flow path opening / closing valve (V3) are opened, and the other flow path opening / closing valves (V1), (V4), (V5) are closed. Therefore, the gas phase inside the liquefied hydrogen storage tank (1) communicates with the outside via the vent gas discharge passage (11), so the vaporized gas (boil-off gas: BOG) in the liquefied hydrogen storage tank (1) is released. Has been.

  In the precool stage, the second flow path opening / closing valve (V2) and the fourth flow path opening / closing valve (V4) are opened, and the other flow path opening / closing valves (V1, V3, V5) are closed. Therefore, in this state, the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure feed pump (2) are cooled by liquefied hydrogen, and the gas vaporized in the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure feed pump (2) is vent gas. The liquid is returned to the liquefied hydrogen storage tank (1) through the discharge path (11), the communication path (13), and the pressurizing gas supply path (10), and the pressure in the liquefied hydrogen storage tank (1) is increased.

  In the rapid pressurization stage, the second flow path opening / closing valve (V2) and the fifth flow path opening / closing valve (V5) are opened, and the other flow path opening / closing valves (V1, V3, V4) are closed. . Therefore, in this state, the gas vaporized by the vaporizer (5) is stored in the liquefied hydrogen through the bypass passage (12), the vent gas discharge passage (11), the communication passage (13), and the pressurization gas supply passage (10). Returned to the tank (1), the inside of the liquefied hydrogen storage tank (1) is rapidly pressurized.

  In the additional pressurization stage, the first flow path opening / closing valve (V1) and the third flow path opening / closing valve (V3) are opened, and the other flow path opening / closing valves (V2, V4, V5) are closed. . Therefore, in this state, hydrogen gas is supplied from the pressure accumulator (9) to the liquefied hydrogen storage tank (1) to further increase the pressure in the liquefied hydrogen storage tank (1).

When filling hydrogen gas into the hydrogen gas receiving container (7) from the liquefied hydrogen storage tank (1) through the liquefied hydrogen pressure pump (2), vaporizer (5), and flow rate controller (6), way shut valve (V1~V 5) is closed. Therefore, the liquefied hydrogen delivered by the liquefied hydrogen pressure pump (2) is vaporized by exchanging heat in the vaporizer (5), and the flow rate is controlled by the flow rate controller (6) to the hydrogen gas receiving container (7). Will be supplied.

  During standby, as in the precooling stage, the second flow path opening / closing valve (V2) and the fourth flow path opening / closing valve (V4) are opened, and the other flow path opening / closing valves (V1), (V3), (V5). Is closed. Therefore, in this state, the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure feed pump (2) are cooled by the liquefied hydrogen and maintained at a low temperature.

Table 1 shows the open / close states of the flow path on-off valves (V1 to V5) at the above-described stages.

Next, the procedure of the preparatory work 1 at the time of filling liquefied hydrogen will be described with reference to FIG.
In the initial state, the internal pressure (P) of the liquefied hydrogen storage tank (1) and the temperature (T) of the liquefied hydrogen pressure pump (2) are measured (step S1).

  In the pre-cooling stage, the second flow path opening / closing valve (V2) and the fourth flow path opening / closing valve (V4) are opened, and the other flow path opening / closing valves (V1, V3, V5) are closed ( Step S2), the temperature (T) of the liquefied hydrogen pressure pump (2) is measured, and the detected temperature (T) of the liquefied hydrogen pressure pump (2) is lower than a preset temperature (Ts), for example, −100 ° C. This state is maintained until the temperature is reached (step S3).

  When the temperature (T) of the liquefied hydrogen pressure pump (2) becomes lower than the preset temperature (Ts), the fourth flow path opening / closing valve (V4) is closed and the fifth flow path opening / closing valve (V5) is opened. The valve is opened (step S4) and the rapid pressurization stage is entered.

  In the above, the temperature (T) at which the end time of the precool stage is detected is set to be lower than the set temperature (Ts). However, in order to shift to the next rapid stage earlier, the temperature setting of the set temperature (Ts) is increased. Alternatively, the precool stage time may be set (for example, 3 minutes). Moreover, you may make it transfer to a rapid pressurization stage directly, without passing through a precool stage.

  In the rapid pressurization stage, the internal pressure (P) of the liquefied hydrogen storage tank (1) is measured, and the detected internal pressure (P) of the liquefied hydrogen storage tank (1) is a preset pressure (Ps), for example, 0.5 MPa or more. This state is maintained until the pressure becomes (step S5).

  When the internal pressure (P) of the liquefied hydrogen storage tank (1) exceeds a preset pressure (Ps), the first flow path opening / closing valve (V1) is opened and the second flow path opening / closing valve (V2) The five-path opening / closing valve (V5) is closed (step S6), and the additional pressurization stage is entered. In the additional pressurization stage, the internal pressure (P) of the liquefied hydrogen storage tank (1) is measured, and the detected internal pressure (P) of the liquefied hydrogen storage tank (1) is set to a preset set pressure (Pe), for example, 0 This state is maintained until a pressure of .6 MPa or higher is reached (step S7).

  When the internal pressure (P) of the liquefied hydrogen storage tank (1) becomes equal to or higher than a preset pressure (Pe), all the flow path opening / closing valves (V1 to V5) are closed to enter the filling state.

In addition, as in the case of the liquefied hydrogen container facility, the procedure of the preparatory work 2 at the time of different liquefied hydrogen filling will be described with reference to FIG.
In this work procedure 2, the opening and closing of each valve in the pre-cooling stage and the additional pressurization stage is the same as in the above-described work procedure 1, but a step (step S8) for measuring the time (t) remaining in the rapid pressurization stage is newly added. Is provided. When the time (t) remaining in the rapid pressurization stage exceeds a preset time (ts), for example, a time within 3 minutes, the liquefied hydrogen storage tank (1) as in the above-described work procedure 1 This state is maintained until the internal pressure (P) reaches a preset pressure (Pe) (step S7).

  When the filling operation of filling hydrogen gas from the liquefied hydrogen storage tank (1) into the hydrogen gas receiving container (7) is completed, the second flow path opening / closing valve (V2) and the fourth flow path opening / closing valve (V4) are opened. The stand-by posture is entered in the same state as the precool stage. In this standby posture, the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure feed pump (2) can be kept cold.

  Furthermore, when the vaporized gas from the vaporizer (5) is returned to the liquefied hydrogen storage tank (1), the liquefied hydrogen storage tank (1) is lowered by filling the hydrogen gas receiving container (7) with hydrogen gas. In addition to supplementing the decrease in internal pressure at the tank, the temperature rise in the liquefied hydrogen supply system can be suppressed, the preparation time for filling can be shortened, and the loss (release amount) of hydrogen gas can be reduced. Can do.

  The present invention can be used for pressurization of a mobile liquefied hydrogen container used for filling hydrogen into a hydrogen gas receiving container such as a fuel cell vehicle.

  DESCRIPTION OF SYMBOLS 1 ... Liquefied hydrogen storage tank, 2 ... Liquefied hydrogen pumping pump, 3 ... Liquefied hydrogen lead-out path, 4 ... Liquefied hydrogen pressure feeding path, 5 ... Vaporizer, 7 ... Hydrogen gas receiving container, 10 ... Pressurized gas supply path, 11 ... Vent gas discharge path, 12 ... bypass path.

Claims (1)

This is a hydrogen supply method in a mobile hydrogen station that supplies liquefied hydrogen derived from the liquefied hydrogen storage tank (1) to the hydrogen gas receiving vessel (7) through the liquefied hydrogen pressure pump (2) and vaporizer (5). And
Before starting the liquefied hydrogen pressure pump (2), the liquefied hydrogen lead-out path (3) and the liquefied hydrogen pressure feed pump (2) for connecting the liquefied hydrogen storage tank (1) and the liquefied hydrogen pressure pump (2) in communication with each other Is cooled by liquefied hydrogen and the vaporized gas is returned to the liquefied hydrogen storage tank (1) via the vent gas discharge path (11), the communication path (13) and the pressurization supply path (10) to return to the liquefied hydrogen storage tank ( A pre-cooling step for boosting 1);
The gas vaporized in the vaporizer (5) at the start of hydrogen supply is stored in the liquefied hydrogen storage tank (1) via the bypass passage (12), vent gas discharge passage (11), communication passage (13), and pressurization supply passage (10). A rapid pressurizing step of returning to the liquefied hydrogen storage tank (1) and rapidly pressurizing the liquefied hydrogen storage tank (1);
A supplementary pressurizing step of supplying hydrogen gas to the liquefied hydrogen storage tank (1) from the pressure accumulator (9) via the pressurization supply path (10) to further pressurize the liquefied hydrogen storage tank (1);
A pressurizing step configured to pressurize the inside of the liquefied hydrogen storage tank (1) by
A method for pressurizing a liquefied hydrogen container in a mobile hydrogen station.

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