JP3181686B2 - Hydrogen recovery and purification equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen recovery and purification apparatus having a function of regenerating a hydrogen storage alloy.

[0002]

2. Description of the Related Art A conventional hydrogen recovery and purification apparatus is disclosed, for example, in Japanese Patent Laid-Open No. 3-271101. This hydrogen recovery and purification device connects a hydrogen utilization device and a hydrogen recovery container having a built-in hydrogen storage alloy and having a heating device and a cooling device attached thereto through an absorption gas line having a first pressure control valve. A discharge gas line having the following structure is connected to the hydrogen recovery container.

[0003] However, in this conventional hydrogen recovery and purification apparatus, when hydrogen gas from the hydrogen utilization apparatus is occluded in the hydrogen storage alloy in the hydrogen recovery vessel cooled by the cooling apparatus, the hydrogen utilization inside the hydrogen utilization apparatus is not performed. However, there is a technical problem that the toxic gas mixed for some reason is occluded together with the hydrogen gas, and the toxic gas is accumulated in the hydrogen storage alloy, so that the capability of hydrogen recovery and purification gradually decreases.
Here, the poisoning gas is a gas that reduces the hydrogen storage capacity of the hydrogen storage alloy, and oxygen and other atmospheric components are known.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional technical problem, and its structure is based on an absorption gas line having a first valve having an open / close function. A hydrogen recovery container, which is connected to the hydrogen utilization device and stores a hydrogen storage alloy that stores hydrogen as hydride, and a second storage device connected to the hydrogen recovery container and having an opening / closing function
A gas line for release with a valve interposed therebetween, a heating device for heating the hydrogen storage alloy in the hydrogen recovery container, and a cooling device for cooling the hydrogen storage alloy so as to store hydrogen,
A first heating device for heating the hydrogen storage alloy to a temperature at which hydrogen is released from the hydrogen storage alloy, and a high temperature of 40 ° C. or higher than a heating temperature of the first heating device so as to release toxic gas from the hydrogen storage alloy. And a second heating device for heating the hydrogen. Then, a vacuum pump for reducing the pressure inside the hydrogen recovery container can be connected to the discharge gas line. Further, the cooling device and the first heating device are constituted by a heat medium passage through which the heat medium from the first heat medium supply device is passed, and the second heating device is constituted by the heat medium from the second heat medium supply device. Can be constituted by a heat medium flow path through which the air flows.

[0005]

The hydrogen storage alloy in the hydrogen recovery container is cooled by the cooling device, hydrogen gas from the hydrogen utilization device is introduced from the gas line for absorption, and hydrogen gas is stored in the hydrogen storage alloy in the hydrogen recovery container. In this state, the hydrogen storage alloy in the hydrogen recovery container is heated at a relatively low temperature by the first heating device. As a result, hydrogen gas is released from the hydrogen storage alloy in the hydrogen recovery container in which hydrogen has been stored, and the released high-purity hydrogen gas flows out through the release gas line. When storing hydrogen gas, the first valve is opened and the second valve is opened.
Close the valve. When releasing hydrogen gas, the first
Close the valve and open the second valve.

When the poisoning gas for the hydrogen storage alloy is mixed into the hydrogen utilization device for some reason and is deposited and accumulated on the hydrogen storage alloy for a long time to gradually reduce the storage capacity, the second heating device is used. Activate That is, after releasing the hydrogen gas from the hydrogen storage alloy, the second heating device is operated to heat the hydrogen storage alloy to a temperature higher by 40 ° C. or more than the heating temperature by the first heating device, The state is maintained for a predetermined time. Thereby, the toxic gas adhering to the hydrogen storage alloy is gradually released.
The released toxic gas is released to the outside through a release gas line. When releasing poisonous gas, the first
Close the valve and open the second valve. At that time, the second
By closing the valve and driving the vacuum pump, the toxic gas can be forcibly discharged to the outside. Thus, the hydrogen storage alloy in the hydrogen recovery container is activated, and the hydrogen storage capacity is regenerated.

[0007] The cooling device and the first heating device are constituted by a heating medium passage through which the heating medium from the first heating medium supply device is passed, and the second heating device is connected by the second heating medium supply device. When the heat storage medium is constituted by a heat medium flow path through which the heat medium flows, the heat storage medium supplied from the first heat medium supply device to the heat medium flow path causes the hydrogen storage alloy in the hydrogen recovery container to pass through. By heating at a relatively low temperature, hydrogen gas can be released from the hydrogen storage alloy in the hydrogen recovery container in which hydrogen has been stored, and the heat supplied to the heat medium flow path from the second heat medium supply device The medium is heated by the medium so that the hydrogen storage alloy in the hydrogen recovery container is heated to a temperature higher than the heating temperature of the first heating device by 40 ° C. or more, and the temperature state is maintained for a predetermined time.
The toxic gas attached to the hydrogen storage alloy can be released.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of a hydrogen recovery and purification apparatus. In the drawing, reference numeral 1 denotes a hydrogen recovery container in which a plurality of hydrogen storage containers are arranged in parallel, and stores a hydrogen storage alloy (metal hydride) that stores hydrogen as a hydride. Each of the hydrogen recovery containers 1 is provided with a temperature sensor 2. On one side of such a hydrogen recovery container 1, absorption branch pipes 3a, 3b branching from the other end of the absorption gas line 3.
Are connected via first valves 4a and 4b each having an opening / closing function. One end of the absorption gas line 3 is connected to a hydrogen utilization device 10 such as a hydrogen-cooled generator, a semiconductor manufacturing facility, or the like. However, the hydrogen utilization device 10 here may be a device that releases hydrogen gas used for recovery or purification, and includes a hydrogen generation device such as an ammonia decomposition device.

Further, on the other side of each hydrogen recovery vessel 1, discharge branch pipes 6a and 6b are connected via second valves 5a and 5b having opening and closing functions, respectively.
The other ends of a and 6b are connected to a gas line 6 for discharge. Hydrogen gas is introduced from the absorption gas line 3 and is recovered or purified by the hydrogen storage alloy in the hydrogen recovery container 1.
It flows out of the discharge gas line 6. Further, a vacuum pump 12 is connected to the discharge gas line 6. The vacuum pump 12 has a function of opening the second valve 5a or 5b, driving the first valve 4a or 4b and the opening / closing valve 5c in a closed state, and depressurizing the inside of the hydrogen recovery container 1. A hydrogen utilization device 10 is usually connected to the other end of the discharge gas line 6 so that hydrogen gas recovered or purified by the hydrogen recovery container 1 is circulated and used.

Each hydrogen recovery container 1 is provided with a heating device 7 and a cooling device 8 for heating or cooling the hydrogen storage alloy in the hydrogen recovery container 1 respectively. The cooling device 8 is, for example, a cold water supply device that supplies cold water. Each heating device 7 includes a first heating device 7a that heats the hydrogen storage alloy at a relatively low temperature so as to release hydrogen, and a hydrogen device that releases toxic gas for the hydrogen storage alloy from the hydrogen storage alloy. A second heating device 7b for heating the storage alloy at a relatively high temperature. Each first heating device 7a is, for example, a hot water or steam supply device that supplies hot water or steam. Each of the second heating devices 7b is, for example, an electric heater.
It is also possible to use a single electric heater or a steam supply device by also using b and the first heating device 7a.

Specifically, the second heating device 7b is set to a temperature higher than the heating temperature of the first heating device 7a by 40 ° C. or more so as to release toxic gas such as air from the hydrogen storage alloy. Provides the ability to heat hydrogen storage alloys. The hydrogen storage alloy reacts with the hydrogen gas and reversibly stores or releases the hydrogen gas. This reaction is based on the hydrogen equilibrium pressure-temperature characteristic (PT characteristic) in the plateau region, and the temperature at the hydrogen equilibrium pressure is determined. From the conditions, when cooled to a low temperature, hydrogen gas is absorbed, and when heated to a high temperature, hydrogen gas is released. Thus, the normal first heating device 7a in the conventional hydrogen recovery / purification device has a hydrogen storage alloy of 150-170.
Since it is intended to release hydrogen gas by heating to about ° C, it is sufficient that the second heating device 7b has a capability of heating the hydrogen storage alloy to 200 ° C or more. Reference numeral 11 denotes a control device that controls the heating device 7 and the cooling device 8 based on a detection signal from the temperature sensor 2.

Next, the operation of the above embodiment will be described. The hydrogen storage alloy in the hydrogen recovery container 1 is cooled by the cooling device 8, the first valve 4a or 4b is opened, and the hydrogen gas from the hydrogen utilization device 10 is transferred from the absorption gas line 3 to the absorption branch pipe 3a. Or, it is introduced into 3b and supplied to the hydrogen recovery container 1. As a result, hydrogen gas starts to be stored in the hydrogen storage alloy in the hydrogen recovery container 1. After the storage of the hydrogen gas by the hydrogen storage alloy is completed, the first heating device 7
By heating the hydrogen storage alloy in the hydrogen recovery container 1 at a relatively low temperature by a, the first valve 4a or 4b is closed and the second valve 5a or 5b is opened. This allows
Hydrogen gas is released from the hydrogen storage alloy in the hydrogen recovery container 1 in which hydrogen has been stored, and the released high-purity hydrogen gas flows out from the release branch pipe 6a or 6b through the release gas line 6.

When the recovery or purification of the hydrogen gas is repeatedly performed in this manner, the poisoning gas for the hydrogen storage alloy is mixed into the hydrogen utilization device 10 for some reason, and the hydrogen storage alloy is mixed with the hydrogen storage alloy for a long time. Adhesion accumulates and gradually reduces the storage capacity. FIG. 3 shows the relationship between the hydrogen storage capacity of the hydrogen storage alloy and the hydrogen storage time. In FIG.
The curve shows the characteristics after the regeneration treatment, the B curve shows the characteristics after poisoning for 2 hours, the C curve shows the characteristics after poisoning for 6 hours, and the D curve shows the characteristics after poisoning for 12 hours. These poisonings were given by opening the hydrogen storage alloy to the atmosphere for a predetermined time. It can be seen from the figure that the hydrogen storage capacity decreases as the poisoning time increases.

The second heating device 7b is operated when the hydrogen storage alloy is poisoned and the hydrogen storage capacity is reduced. First, after the hydrogen gas is released from the hydrogen storage alloy, the first valve 4a or 4b is shut off to open the second valve 5a or 5b and the opening / closing valve 5c, and the second heating device 7b is operated. It is shifted to the reproduction operation in the normal time after operation t ₁ ~t ₂ shown. As is known from the figure, the second heating device 7b is turned off during the normal operation, and the second heating device 7b is turned on during the regeneration operation. The hydrogen storage alloy is heated to a high temperature T ₁ of the above 40 ° C. than the heating temperature by the first heating device 7a, if maintaining the temperature state for a predetermined time period (t ₃ ~t _4), the hydrogen storage alloy The poisonous gas adhering to is gradually released. The released poisonous gas is discharged to the outside from the one discharge branch pipe 6a or 6b through the discharge gas line 6. that time,
By closing the opening / closing valve 5c and driving the vacuum pump 12, the toxic gas can be forcibly discharged to the outside.

Thus, the hydrogen storage alloy in the hydrogen recovery container 1 is activated, and the hydrogen storage capacity is regenerated as shown by the curve A in FIG. By the way, as shown in FIG. 1, an inert gas inlet pipe 13 having an opening / closing valve 4c and an opening / closing valve 13a is sequentially connected to the absorption gas line 3 from the hydrogen utilization device 10 side, and the opening / closing valve of the discharge gas line 6 is connected. 5c
An inert gas outlet pipe 14 having an on-off valve 14a can be connected to the upstream side. When the hydrogen storage alloy is regenerated, both the open / close valves 4c and 5c are closed, the hydrogen storage alloy is heated by the second heating device 7b, and both the open / close valves 13a and 14a are opened. If an inert gas is sent from the hydrogen storage alloy 13 into the hydrogen recovery container 1, the toxic gas released from the hydrogen storage alloy can be discharged from the inert gas outlet pipe 14 together with the inert gas. Gas emission can be ensured. The inert gas remaining in the hydrogen recovery container 1 after the regeneration treatment is discharged by driving the vacuum pump 12 or the like.

FIG. 4 shows the relationship between the hydrogen storage amount ratio (Q / Q ₀ ) and the temperature (° C.). Here, the hydrogen storage amount ratio is the hydrogen storage amount Q of the hydrogen storage alloy after the regeneration treatment from the poisoned state.
The temperature (° C.) is the ratio of the hydrogen storage amount Q ₀ of a _non- poisoned and non-poisoned activated hydrogen storage alloy.
Is a predetermined temperature T ₁ of shown, the predetermined temperature T ₁ of the hold time (t ₃ ~t ₄ shown in FIG. 2) is 1 hour. In the figure, the F curve shows the characteristics after poisoning for 2 hours, the G curve shows the characteristics after poisoning for 4 hours, the H curve shows the characteristics after poisoning for 6 hours, and the I curve shows the characteristics after poisoning for 12 hours. , Respectively. This poisoning was performed by opening the hydrogen storage alloy to the atmosphere for a predetermined time in the same manner as described above. As can be seen from the figure, as the poisoning time increases, the recovery of the hydrogen storage amount ratio (Q / Q ₀ ) cannot be said to be particularly good at a relatively low temperature of T ₁ = 200 ° C. or less. As the temperature rises, the hydrogen storage ratio (Q /
Q ₀ ) gradually recovers, and the hydrogen storage ratio (Q / Q ₀ ) at a relatively high temperature of about T ₁ = 400 ° C. or more recovers relatively well regardless of the length of the poisoning time.

The operation of occluding or releasing hydrogen gas is performed by one of the first and second valves 4a and 4b, the second valves 5a and 5b, and the two on-off valves 4c and 5c. It is possible to carry out each of the steps, or simultaneously in both hydrogen recovery vessels 1. The same applies to the activation treatment of the hydrogen storage alloy.

FIG. 5 shows a second embodiment of the hydrogen recovery / purification apparatus. Parts substantially the same as those in the first embodiment are denoted by the same reference numerals, and their description is omitted. In this embodiment, the cooling device 8 and the first heating device 7a are constituted by the heating medium passage 9 through which the heating medium from the first heating medium supply device 16 is passed, and the second heating device 7b is , The second heat medium supply device 17
And the same heat medium flow passage 9 through which the heat medium flows.

That is, the heat medium cooled by the first heat medium supply device 16 so as to absorb hydrogen gas is sent into the heat medium passage 9 arranged in each hydrogen recovery container 1 and cooled. The heat medium, which functions as the device 8 and is heated to a relatively low temperature so as to release hydrogen gas, is supplied to the first device.
A heating medium which functions as a heating device 7a and which is heated to a relatively high temperature by the second heat medium supply device 17 so as to release the poisonous gas for the hydrogen storage alloy from the hydrogen storage alloy. To function as the second heating device 7b.

Specifically, the outlet port 16a of the first heat medium supply device 16 is connected to one of the first heat medium pipe 21 having the open / close valve 20 and the second heat medium pipe 23 having the open / close valve 22. It is connected to the inlet of the heat medium flow path 9 in the hydrogen recovery container 1 and connected to the inlet of the heat medium flow path 9 in the other hydrogen recovery container 1 by a third heat medium pipe 25 having an open / close valve 24. .

An outlet port 17a of the second heat medium supply device 17 is connected to a fourth heat medium pipe 27 having an open / close valve 26 by a second heat medium pipe 23 having an open / close valve 22. Heat medium flow path 9 in 1
And an opening and closing valve 24
The heat medium pipe 25 is connected to the inlet of the heat medium flow path 9 in the other hydrogen recovery container 1.

Further, an inlet port 16b of the first heat medium supply device 16 is connected to a heat medium in one hydrogen recovery vessel 1 from a fifth heat medium pipe 31 having an open / close valve 30 by a sixth heat medium pipe 32. While connecting to the outlet of the flow path 9,
The seventh heat medium pipe 33 is connected to the outlet of the heat medium flow path 9 in the other hydrogen recovery container 1. The inlet port 17b of the second heat medium supply device 17 is provided with an on-off valve 34.
From the eighth heat medium pipe 35 having the
Is connected to the outlet of the heat medium flow passage 9 in one hydrogen recovery container 1 by the first heat recovery pipe 1, and is connected to the outlet of the heat medium flow path 9 in the other hydrogen recovery container 1 by the seventh heat medium pipe 33. .

The first heat medium supply device 16 is a device for generating, for example, cold water, hot water or steam at a predetermined temperature, and the second heat medium supply device 17 is a device for generating a relatively high temperature, for example, overheated steam. is there. The second heat medium supply device 17 has a high temperature T _{1 that} is 40 ° C. or more higher than the heating temperature of the first heat medium supply device 16 so as to release toxic gas such as air attached to the hydrogen storage alloy. Gives the ability to heat the hydrogen storage alloy. The first heat medium supply device 16 heats the hydrogen storage alloy to about 150 to 170 ° C. so that hydrogen gas is released from the hydrogen storage alloy. It is sufficient to provide the ability to heat the hydrogen storage alloy to 200 ° C. or higher as in the embodiment.

The on-off valves 20, 22, 2
4, 26, 30, and 34 are appropriately opened and closed, and the heat medium heated to a relatively low temperature by the first heat medium supply device 16 is supplied to the heat medium flow path 9 to thereby reduce the hydrogen of the hydrogen storage alloy. By supplying the heat medium heated to a relatively high temperature by the second heat medium supply device 17 to the heat medium flow path 9,
Second heating device 7 for releasing toxic gas of hydrogen storage alloy
Functions as b. On the other hand, as the cooling device 8, the heat medium cooled to an appropriate temperature from the first heat medium supply device 16 is supplied to the heat medium passage 9 to function. Thus, the same operation as in the first embodiment can be obtained.

The heat medium pipe and heat medium flow passage 9 through which the heat medium from the first heat medium supply device 16 flows, and the heat medium pipe and heat medium through which the heat medium from the second heat medium supply device 17 flows It is also possible to separate the heat medium from the flow path 9 to prevent mixing.

[0026]

As will be understood from the above description,
According to the hydrogen recovery and purification apparatus of the present invention, the function of regenerating the poisoned hydrogen storage alloy is added, and the hydrogen storage alloy can be efficiently regenerated without removing the hydrogen storage alloy from the hydrogen recovery and purification apparatus. Of the hydrogen recovery and purification device can be used for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a hydrogen recovery and purification apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing temperature-time characteristics of the second heating device.

FIG. 3 is a diagram showing a hydrogen storage capacity-hydrogen storage time characteristic.

FIG. 4 is a diagram showing a hydrogen storage amount ratio-temperature characteristic.

FIG. 5 is a schematic diagram showing a hydrogen recovery and purification apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

1: hydrogen recovery container, 2: temperature sensor, 3: gas line for absorption, 3a, 3b: branch pipe for absorption, 4a, 4b: first
Valve, 4c: open / close valve, 5a, 5b: second valve,
5c: open / close valve, 6: discharge gas line, 6a, 6
b: discharge branch pipe, 7: heating device, 7a: first heating device, 7b: second heating device, 8: cooling device, 9: heat medium flow path, 10: hydrogen utilization device, 12: vacuum pump, 13 : Inert gas inlet pipe, 13a: open / close valve, 14: inert gas outlet pipe, 14a: open / close valve, 16: first heat medium supply device, 17: second heat medium supply device, 21, 23, 25,
27, 31, 32, 33, 35: heat medium flow path, 20, 2
2, 24, 26, 30, 34: open / close valve.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-271101 (JP, A) JP-A-2-9701 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01B 3/00-3/56 B01D 53/14

Claims (3)

(57) [Claims] 1. A hydrogen recovery container which is connected to a hydrogen utilization device by an absorption gas line having a first valve having an opening / closing function and stores a hydrogen storage alloy which stores hydrogen as a hydride, and a hydrogen recovery container for storing the hydrogen storage alloy. A discharge gas line connected to the container and having a second valve having an opening / closing function, a heating device for heating the hydrogen storage alloy in the hydrogen recovery container, and cooling for cooling the hydrogen storage alloy so as to store hydrogen A first heating device for heating the hydrogen storage alloy to a temperature at which hydrogen is released from the hydrogen storage alloy, and a heating temperature lower than the first heating device so as to release the toxic gas from the hydrogen storage alloy. A second heating device for heating to a high temperature of 40 ° C. or higher, a hydrogen recovery and purification device. 2. The hydrogen recovery and purification apparatus according to claim 1, wherein a vacuum pump for reducing the pressure inside the hydrogen recovery container is connected to the discharge gas line. 3. The cooling device and the first heating device are configured by a heating medium passage through which the heating medium from the first heating medium supply device is passed, and the second heating device is configured by the second heating medium supply device. The hydrogen recovery and purification apparatus according to claim 1 or 2, wherein the apparatus is configured with a heat medium passage through which the heat medium passes.