JP2008254986A - Activation device and method for hydrogen storage alloy vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the reduction of activation time by making hydrogen pressure and fluid pressure almost equal, thus making the suppression of the deformation of a hydrogen storage alloy vessel and heat exchange at high efficiency consistent. <P>SOLUTION: Regarding the activation device and method for a hydrogen storage alloy vessel, hydrogen (18a) is fed to the inside of a hydrogen storage alloy vessel (20) arranged at the inside of a pressure resistant vessel (1) via hydrogen piping (3), the flow rate of a fluid (6) fed to the inside of the pressure resistant vessel (1) is controlled by a charging-pressurizing means (14), and hydrogen pressure and fluid pressure are made almost equal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus and method for activating a hydrogen storage alloy container, and in particular, by applying a fluid pressure substantially equal to the hydrogen pressure applied to the inside of the hydrogen storage alloy container to the outside, the deformation and efficiency of the hydrogen storage alloy container are suppressed. The present invention relates to a novel improvement for achieving both heat exchange and shortening the activation time.

  Conventionally, as a method for activating a hydrogen storage alloy that has been used, for example, a powdered hydrogen storage alloy is placed in a sealed container provided with a hydrogen introduction tube, and is vacuumed at a temperature of 80 ° C. or more for several hours to several tens of hours. After pulling, a method of introducing hydrogen at several atmospheres or more at a temperature below room temperature is common. Here, evacuation at a high temperature in the first half is called “depressurization activation”, and high-pressure hydrogen introduction at a low temperature in the second half is called “pressurization activation”. Hydrogen-absorbing alloys that are difficult to activate, such as BCC-based hydrogen-absorbing alloys, have higher pressure activation conditions and higher vacuums, and lower pressure activation conditions than AB5- and AB2-based alloys that are easily activated. And high pressure is necessary. In addition, as the activation conditions are increased, the activation time is generally shortened. That is, the time until activation is completed is shorter when the pressure activation step is performed at 150 ° C. than 100 ° C., and when the pressure activation step is performed at 0 ° C. than 20 ° C. or 10 MPa rather than 1 MPa.

  However, when a practical hydrogen storage alloy container is activated, the design conditions and the pressure of the container are naturally limited, and thus the activation conditions cannot be increased without limit. A metal container has a relatively wide allowable temperature range, but exceeding the allowable pressure limit may cause deformation or rupture of the container. Furthermore, since the volume of the hydrogen storage alloy itself changes greatly before and after activation, it is necessary to take into account the expansion pressure of the alloy in addition to the hydrogen gas pressure. That is, the hydrogen pressure introduced during the pressure activation must be lower than the original design pressure of the container. For this reason, in a container containing a hydrogen storage alloy having a slow activation rate, there is a drawback that the time required for activation becomes long.

Further, in order to improve the above-described conventional method, methods described in the following Patent Documents 1 and 2 have been proposed.
That is, in the method of Patent Document 1, a method has been devised in which a hydrogen storage alloy is encapsulated in a plastic container such as a polyethylene bag together with hydrogen and activated by cold isostatic pressing together with the bag. However, considering that the hydrogen storage alloy can absorb nearly 1000 times its own volume of hydrogen, for example, in order to activate a hydrogen storage alloy having a volume of 1 L (approximately 6 to 8 kg), a plastic having a volume of 1 m ³ is required. A container is required. Since the volume of the plastic container increases in proportion to the amount of alloy to be activated, this method is not suitable for mass processing.

  Moreover, in the case of the method of the above-mentioned patent document 2, the hydrogen storage alloy container which opened | released the hydrogen absorption / release hole was put into the vessel provided with the hydrogen gas supply device, the inert gas supply device, and the decompression device, and the inside of the vessel was decompressed. In addition, an apparatus and a method for activating hydrogen by applying hydrogen pressure have been proposed. In this method, since the internal and external pressures of the hydrogen storage alloy container can be made uniform, hydrogen activation can be performed at a high pressure without considering the deformation of the container due to the pressure difference. However, this method has the following drawbacks. (1) Since the entire vessel must be depressurized, it is more difficult to increase the degree of vacuum during the depressurization activation than when depressurizing the hydrogen storage alloy container alone. (2) A large amount of hydrogen is required because not only the alloy container but also the entire vessel must be filled with high-pressure hydrogen. (3) The jacket for heat exchange must be structured to withstand both the internal pressure during decompression and the external pressure during pressurization. (4) When the hydrogen storage alloy container is taken out after activation, the inside of the vessel is replaced with inert gas after releasing hydrogen, and the alloy container must be covered with the inert gas. The equipment and the manufacturing process were complicated.

Japanese Patent No. 2699136 JP 2000-17408 A

Since the conventional method for activating a hydrogen storage alloy container is configured as described above, the following problems exist.
That is, in order to prevent deformation of the container, the hydrogen pressure during the pressurization activation is kept below a certain level, so that it takes time to activate. Therefore, a method has been devised to reduce the activation time by putting the hydrogen storage alloy before putting into the container together with hydrogen gas into a plastic container and applying hydrostatic pressure, but the container volume before activation becomes very large. Therefore, it is not a realistic method. In addition, a hydrogen storage alloy container with an open lid was placed in a vessel, and hydrogen was introduced into the vessel to devise a method for activation while keeping the pressure inside and outside the alloy container equalized. However, there are problems that the amount of hydrogen required for the process increases, and that it is difficult to take out the alloy container after the activation is completed.

  The activation apparatus for a hydrogen storage alloy container according to the present invention can arrange a hydrogen storage alloy container in a pressure resistant container, and a hydrogen pipe communicating with a hydrogen source disposed outside the pressure resistant container is connected to the hydrogen storage alloy container. The pressure vessel is provided with an inlet for fluid flowing into the pressure vessel, and the pressure vessel is connected to a filling / pressurizing means capable of filling and pressurizing the fluid. The method for activating the hydrogen storage alloy container according to the present invention includes a heat storage means for removing heat from the fluid, and the activation method for the hydrogen storage alloy container according to claim 1 or 2. And a method of activating the hydrogen storage alloy in the hydrogen storage alloy container while adjusting the pressure of hydrogen introduced into the hydrogen storage alloy container and the pressure of the fluid to be balanced.

Since the apparatus and method for activating a hydrogen storage alloy container according to the present invention are configured as described above, the following effects can be obtained.
That is, since the hydrogen storage alloy container is placed in a pressure vessel, and the outside of the hydrogen storage alloy container is filled with a fluid, the hydrogen is activated while balancing the hydrogen pressure and the fluid pressure. The high pressure activation can be performed while suppressing deformation, and the heat of hydrogen absorption can be removed by the fluid, so that the hydrogen activation time can be shortened.

  The present invention applies a fluid pressure substantially equal to the hydrogen pressure applied to the inside of the hydrogen storage alloy container to achieve both suppression of deformation of the hydrogen storage alloy container and efficient heat exchange, and shortening the activation time. An object of the present invention is to provide an apparatus and method for activating a hydrogen storage alloy container.

Hereinafter, preferred embodiments of an apparatus and method for activating a hydrogen storage alloy container according to the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a hydrogen activation apparatus according to the present invention, and a hydrogen pipe 3, a differential pressure gauge 4, and an air vent valve 5 are provided on a lid portion 2 of a pressure vessel indicated by reference numeral 1.

A fluid tank 7 for storing a fluid 6 is connected to the main body 1A of the pressure vessel 1 through a fluid pipe 8, and the fluid pipe 8 is connected to the inlet 9 and the outlet 10 of the main body 1A. Yes.
The fluid pipe 8 is provided with first, second, and third valves 11, 12, and 13, and the fluid 6 is placed between the first and third valves 11 and 13 in the pressure vessel 1. A filling / pressurizing means 14 including a filling / pressurizing pump for filling / pressurizing the inside is provided.

The differential pressure gauge 4 and the filling / pressurizing means 14 are connected to an output control unit 15 and control the feed amount of the fluid 6 of the filling / pressurizing means 14 based on the differential pressure 4 a from the differential pressure gauge 4. It is configured to be able to.
A tank-like hydrogen source 18 composed of a high-pressure hydrogen source is connected to the hydrogen pipe 3 via a pressure gauge 16 and a regulator 17.

  Next, the hydrogen activation procedure in the above-described configuration will be described. First, as shown in FIG. 1, each hydrogen storage alloy container 20 in which the reduced pressure activation process is completed is attached to the hydrogen pipe 3, and the lid 2 is closed as shown in FIG. After filling the fluid 6 into the pressure-resistant vessel 1 while evacuating the air in the internal process with the lid 2 closed, hydrogen 18a is introduced. The hydrogen is gradually pressurized while controlling the feed by the filling / pressurizing means 14 so that the differential pressure between the hydrogen 18a and the fluid 6 becomes zero, and when the target pressure is reached, the pressure is kept constant. Wait until the activation is finished. After completion of the hydrogen activation, the pressure of the fluid and the pressure of hydrogen are simultaneously released, and the hydrogen pressure is lowered to the allowable pressure of the hydrogen storage alloy container 20 or less. Finally, the lid 2 of the pressure vessel 1 is opened and the activated hydrogen storage alloy vessel 20 is removed.

  The fluid 6 is preferably water, but oil or antifreeze may be used depending on the activation temperature. As a means for eliminating the differential pressure between the hydrogen pressure and the fluid pressure, in addition to the method of adjusting the feed output according to the output of the differential pressure gauge 4 as shown in FIG. A method of balancing the pressure and the fluid is also possible.

  The internal and external pressures of the hydrogen storage alloy container 20 can be kept in equilibrium by the above-described hydrogen storage alloy container activation device and method, so that the hydrogen storage alloy container 20 can be activated at a high hydrogen pressure while minimizing deformation of the hydrogen storage alloy container 20 At the same time, since the hydrogen absorption heat generated by the heat transfer to the surrounding fluid 6 can be removed, the activation time can be shortened. Moreover, if the heat removal means 30 including a cooling coil or the like into which a refrigerant is flown as shown in FIG. 3 is arranged in the pressure vessel 1, the removal efficiency of the hydrogen absorption heat can be greatly improved, and the activation time can be further shortened. it can. Here, in addition to the heat removal means 30 for the fluid 6 illustrated in FIG. 3, a cooling coil is wound around the outside of the pressure vessel 1 and the whole pressure vessel 1 is cooled, or a part of the fluid piping is coiled. A method of cooling by immersing in a cooling tank and forcibly circulating a fluid is also possible.

Next, in order to compare the activation method of the hydrogen storage alloy container according to the present invention with the conventional method, the present applicant uses a hydrogen storage alloy tank with a rated hydrogen capacity of 50 NL (external size φ50 mm × H132 mm, built-in AB5 alloy 330 g). The results of the activation rate comparison were described.
The activation procedure according to the conventional method is as follows. (1) Immerse the alloy tank in a water bath at 80 ° C and evacuate for 5 hours. (2) Immerse the alloy tank in a water bath at 15 ° C. and introduce 1 MPa of hydrogen into the interior. The amount of hydrogen absorbed in the alloy tank was measured with a mass flow meter.
The activation procedure according to the method of the present invention is as follows. (1) Immerse the alloy tank in a water bath at 80 ° C and vacuum for 5 hours. (2) An alloy tank is placed in a pressure vessel in which a coil in which water of 15 ° C. circulates is provided, and a hydrogen pipe is connected to close the pressure vessel. (3) Fill the pressure vessel with water, gradually increase the hydrogen pressure, and equilibrate to increase the water pressure. (4) When both the hydrogen pressure and water pressure reach 5 MPa, stop the pressure increase and measure the hydrogen absorption amount with a mass flow meter. Next, FIG. 4 shows a change in the hydrogen absorption amount of the MH tank when the time when the hydrogen filling is started is set to zero. It was found that the activation that took 3.5 hours in the conventional method was completed in about 2 hours in the method of the present invention.

It is a block diagram which shows the activation apparatus and method of the hydrogen storage alloy container by this invention. It is a block diagram which shows the state which closed the cover part of FIG. It is a block diagram which shows the other form of FIG. It is a characteristic view which shows the speed comparison of the activation time of this invention method and the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-resistant container 1A Main-body part 2 Lid part 3 Hydrogen piping 4 Differential pressure gauge 5 Air vent valve 6 Fluid 7 Fluid tank 8 Fluid piping 9 Inlet 10 Outlet 11-13 First to third valves 14 Filling / pressurizing means 15 Output Control part 16 Pressure gauge 17 Regulator 18 Hydrogen source 18a Hydrogen 20 Hydrogen storage alloy container 30 Heat removal means

Claims (3)

  A hydrogen storage alloy container (20) can be disposed in the pressure resistant container (1), and a hydrogen pipe (3) communicating with a hydrogen source (18) disposed outside the pressure resistant container (1) includes the hydrogen storage alloy container. (20), the pressure vessel (1) is provided with an inlet (9) for the fluid (6) to flow into the pressure vessel (1), and the pressure vessel (1) has the fluid (6 ) Is an apparatus for activating a hydrogen storage alloy container, to which a filling / pressurizing means (14) capable of filling and pressurizing) is connected.   The apparatus for activating a hydrogen storage alloy container according to claim 1, further comprising heat removal means (30) for removing heat of the fluid (6).   Using the hydrogen storage alloy container activation device according to claim 1 or 2, the pressure of hydrogen (18a) introduced into the hydrogen storage alloy container (20) and the pressure of the fluid (6) are balanced. And activating the hydrogen storage alloy in the hydrogen storage alloy container (20) while adjusting the temperature of the hydrogen storage alloy container.

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