JPS6357679B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a reliquefaction device for generated gas in a low-temperature liquefied gas storage facility or the like. [Prior Art] In a low-temperature liquefied gas storage facility, normal-temperature shipping of the low-temperature liquefied gas and reliquefaction of the generated gas are usually not performed at the same time. Figure 4 shows an example of a conventional low-temperature liquefied gas storage facility. In order to ship low-temperature liquefied gas at room temperature, low-temperature liquefied gas in a low-temperature liquefied gas storage tank a is guided to a heater c via a shipping pipe b. By heating and raising the temperature with seawater or steam d in the heater c, the room-temperature liquefied gas e is supplied to the demand f, and the cold energy of the low-temperature liquefied gas is simply discarded into the sea or the like. On the other hand, low temperature liquefied gas storage tank a
The evaporated gas generated from inside is led to the compressor h via the knockout drum g, where it is compressed, and then liquefied by the condenser j, which is designed to be cooled using seawater i, etc. The liquefied gas is returned to the low temperature liquefied gas storage tank a via the storage tank k, or is supplied to the demand purpose f. As described above, in the past, since there was no simultaneous shipping of low-temperature gas at room temperature and reliquefaction of the generated evaporated gas, it was not possible to effectively utilize the cold energy of the shipping liquid for reliquefaction of the evaporated gas. For this reason, Japanese Patent Application No. 57-65704 discloses a technique for storing the cold energy from the shipment of low-temperature liquefied gas and effectively utilizing it for reliquefying the generated gas without simultaneous reliquefaction. [Problems to be Solved by the Invention] However, the invention disclosed in Japanese Patent Application No. 57-65704 merely connects containers containing different metal hydrides with a hydrogen gas flow path. ,
At the late stage (final stage) of the reaction of storing cold energy and reliquefying the generated gas, the differential pressure between the containers becomes smaller.
There is a problem in that hydrogen gas does not move smoothly, making it difficult to store cold and cool the generated gas. Furthermore, when there is insufficient cold energy from the low-temperature liquefied gas to be shipped, or when there is no shipment of low-temperature liquefied gas for a long period of time, it is not possible to re-liquefy the generated gas using cold energy. The present invention was made in view of these circumstances, and it is possible to effectively use the cold energy generated during shipping of low-temperature liquefied gas to re-liquefy the generated gas at any time regardless of the shipment, and to store the cold energy and cool the generated gas. [Means for solving the problem] The purpose is to provide an apparatus that can stably promote the reaction even in the late stage of the reaction, and can compensate for the lack of cooling heat from the shipping fluid.[Means for solving the problem] The present invention is an attempt to solve the above-mentioned technical problem, and consists of two heat transfer systems installed in one of two containers that separately house different types of metal hydrides and are connected to each other through a hydrogen gas flow path. one of the heat transfer paths communicates with a shipping line connected to the low temperature storage tank, and the other heat transfer path communicates with a generated gas line connected to the low temperature storage tank, and the hydrogen gas flow path The present invention relates to a reliquefaction device for low-temperature liquefied gas, characterized in that it is equipped with a hydrogen gas pressure adjustment device. [Function] Therefore, in the present invention, the reaction of the metal hydride during cold storage and reliquefaction of generated gas can be promoted using the hydrogen gas pressure regulating device. [Examples] Examples of the present invention will be described below with reference to the drawings. As shown in Figure 1, in order to re-liquefy the generated gas that evaporates from the low temperature storage tank 1, A and B have different decomposition (generation) temperatures in an equal pressure hydrogen gas atmosphere.
Container 2 that separately stores two types of metal hydrides.
and 3. As shown by line a in FIG. 3, metal hydride A has a characteristic of having a lower equilibrium temperature in a hydrogen gas atmosphere under the same pressure than metal hydride B shown by line b. In the case of Fig. 3, metal hydride A is Ti.Cr _1.8 (titanium/chromium), and metal hydride B is Mm.Ni _{4.15.Fe 0.85} (mitsu metal, nickel, iron). Two independent heat transfer paths 4 and 5 are provided in the container 2.
The generated gas line 7 is connected to the heat transfer path 4 while the generated gas from the low temperature storage tank 1 is pressurized by the compressor 6.
and is returned to the tank 1 via a return line 10 equipped with a drum 8 and a pump 9 that can be activated automatically or manually. In addition, a shipping pump 11 is connected to the heat transfer path 5 and to the low temperature storage tank 1.
A shipping line 12 is connected via the shipping line 12. A heater 13 is provided on the downstream side of the container 2 of the shipping line 12, and a communication channel 14 is provided between the shipping line 12 on the downstream side and the return line 10. The container 3 is also provided with a heat transfer path 15, and the heat transfer path 15 is provided with a flow path 16 for passing water, air, or other heat medium, and a cutoff valve 17 is provided between the containers 1 and 2. They are connected through a hydrogen gas flow path 18. In the figure, reference numerals 19 and 20 indicate emergency cooling lines for promoting regeneration or freezing effect when the cold energy of the shipped liquid cannot be used for a long period due to an accident or the like, or when the temperature of the cooling medium in the container 3 is high. In the above configuration, a flow path 21 is provided in the hydrogen gas flow path 18 connecting between the containers 2 and 3 so as to straddle the cutoff valve 17, and the flow path 21 includes an on-off valve 24a,
24b, 24c, 24d and the correction compressor 22 constitute a hydrogen gas pressure adjustment device 23 that can arbitrarily change the hydrogen gas pressure in the containers 2 and 3. Next, the action will be explained. The generated gas generated in the low temperature storage tank 1 is introduced by the compressor 6 via the generated gas line 7 into the heat transfer path 4 provided in the container 2, and by opening the shutoff valve 17, hydrogen gas is passed between the containers 2 and 3. can be moved, and the cooling fluid of the container 3 is allowed to flow through the flow path 16. Then, the metal hydride A is heated by the generated gas introduced into the heat transfer path 4 and the decomposition reaction is promoted, and the hydrogen gas pressure in the container 2 tends to increase, while the hydrogen gas introduced into the heat transfer path 15 of the container 3 Since the metal hydride B is cooled by the cooling fluid and the temperature is kept constant, the hydrogen gas pressure becomes constant, and hydrogen gas flows from the container 2 to the container 3. When the pressure inside the container tends to increase, the hydrogen gas that has flowed into the container 3
Promote the production reaction of metal hydride B. This generated heat is removed by the cooling fluid from the flow path 16, so that a constant temperature and constant hydrogen gas pressure are maintained until the interior of the container 3 is saturated with metal hydride. Therefore, the hydrogen gas pressure within the container 2, which is connected to the container 3 through the hydrogen gas flow path 18, is kept constant;
The temperature of metal hydride A is maintained at a temperature in equilibrium with this. As a result, the generated gas introduced into the heat transfer path 4 is stripped of heat and re-liquefied, collected in the drum 8, and then transferred to the return line 1 by the return pump 9.
0 to the cold storage tank 1 or merged into the shipping line 12 via the connecting channel 14. By reliquefying the generated gas in this manner, the pressure in the low temperature storage tank 1 can be maintained below a certain level. Due to the reliquefaction of the generated gas, the decomposition reaction of the metal hydride A in the container 2 progresses, hydrogen gas is lost, and the metal hydride A decreases. For this purpose, the playback operation is performed as follows. When shipping the stored liquid from the low temperature storage tank 1, the shipping liquid is passed through the heat transfer path 5 of the container 2 to cool the metal hydride A, while the heating fluid (the cooling fluid ) and open the shutoff valve 17 to allow hydrogen gas to freely move between the containers 2 and 3. container 2
The metal hydride A in the container 3 is cooled by the shipping liquid, and the hydrogen gas pressure parallel to it decreases, while the metal hydride B in the container 3 is heated by the heating fluid to accelerate the decomposition reaction, and the hydrogen gas pressure in the container 3 is accelerated. The hydrogen gas pressure tends to rise, and hydrogen gas flows into the container 2 side.
This inflow hydrogen gas promotes the formation of metal hydride A in the container 2, and the heat of formation is regenerated as the shipping liquid is removed, and the generation proceeds until the inside of the shipping 2 is saturated with metal hydride A. Ru. An example of the reliquefaction of the generated gas and the regeneration of the metal hydride in the container 2 will be shown below in conjunction with FIG.

【table】

[Table] In addition, in the above, by selecting a combination of metal hydrides A and B with an appropriate regeneration temperature according to the type of stored liquid, the amount of cooling heat available for the low-temperature shipping liquid can be reduced by the amount of reliquefaction heat of the generated gas. Therefore, as mentioned above, the regeneration of metal hydride A poses no problem in terms of calorific value. On the other hand, when the shutoff valve 17 is opened and the reaction is started during the storage of the cold energy and the cooling of the generated gas, the reaction proceeds at a fast rate due to the large pressure difference within the containers 2 and 3; As the process progresses towards the end, the pressure difference between containers 2 and 3 decreases, making it difficult for the hydrogen gas to move smoothly. Therefore, the reaction takes time, and cold storage and reliquefaction of the generated gas become less effective. become unable. For this reason, when the reaction during cold storage approaches the final stage,
After closing the shutoff valve 17 and opening the on-off valves 24c and 24d, the correction compressor 22 is operated to actively supply hydrogen gas to the container 2, thereby causing a rapid reaction. In addition, when the reaction during reliquefaction of generated gas approaches the final stage, the shutoff valve 17 and the on-off valves 24c and 24d are closed, the on-off valves 24a and 24b are opened, and the compensating compressor 22 is operated. The generated hydrogen gas is actively sent to the container 3 for rapid reaction. In the above operation, by repeatedly using the metal hydrides A and B in containers 2 and 3, it becomes possible to constantly reliquefy the generated gas regardless of whether or not the low-temperature shipping liquid is operated. That is, it is possible to perform an independent reliquefaction operation of only the generated gas and a simultaneous operation of the generated gas reliquefaction operation and the cold storage operation using the low-temperature shipping liquid. In addition, by operating the hydrogen gas pressure regulator 23 in the late stage (final stage) of the reaction during cold storage and reliquefaction of generated gas to actively move hydrogen gas, the reaction can be quickly stabilized until the final stage. Therefore, efficient cold storage and reliquefaction of generated gas can be achieved. When reliquefying the generated gas and storing cold at the same time, the shutoff valve 1 of the hydrogen gas flow path 18 between the containers 2 and 3
By leaving 7 open, when the cooling energy (shipment amount) of the shipping liquid is less than the amount of heat for reliquefying the generated gas, hydrogen gas moves from container 2 to container 3 to compensate for the lack of cooling heat for reliquefying the generated gas. refill. In the opposite case, hydrogen gas moves from container 3 to container 2 to generate metal hydride A in container 2, thereby storing the cold heat of the shipping liquid. In addition, when there is a shipping operation, the liquid re-liquefied in the container 2 is pressurized by the return pump 9 and pushed into the shipping line 12 through the communication channel 14, thereby further improving the energy saving effect. . Furthermore, if there is no shipping operation for a long period of time due to an accident or the like, cold energy cannot be used, but since it is equipped with a hydrogen gas pressure adjustment device 23, the hydrogen gas pressure in the containers 2 and 3 can be changed at will. This makes it possible to ensure cooling and heat regardless of whether shipping operations are being carried out or not. In other words, it also has independence as a refrigerator. FIG. 2 shows the same basic idea as the embodiment shown in FIG.
This is the case where a plurality of 3 are installed in parallel, and in this way, the ability to store cold and reliquefy generated gas can be greatly increased. It should be noted that the present invention is not limited only to the above-mentioned embodiments, and various changes may be made without departing from the gist of the present invention. [Effects of the Invention] According to the above-described low-temperature liquefied gas reliquefaction apparatus of the present invention, the following excellent effects can be achieved. (i) The cold energy from shipping low-temperature liquefied gas can be effectively used to re-liquefy generated gas. (ii) The generated gas can be reliquefied regardless of the shipment of low-temperature liquefied gas. (iii) Since the generated gas can be reliquefied at a low temperature, the amount of flash gas will be reduced when the reliquefied liquid is returned to the low temperature storage tank. Therefore, the discharge pressure and suction amount of the compressor that compresses the generated gas are reduced, the required power is reduced, and the compressor can be made smaller. (iv) By being equipped with a hydrogen gas pressure adjustment device, the reaction during cold storage and reliquefaction of generated gas can proceed quickly to the final stage, and the cold storage and generated gas reliquefaction operations can be performed efficiently within a short time. I can do it. (v) Equipped with a hydrogen gas pressure adjustment device, even in the event that shipments are no longer carried out, cooling and heat can be ensured by adjusting the hydrogen gas pressure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing another embodiment of the present invention, Fig. 3 is a graph showing an example of the relationship between the equilibrium pressure and equilibrium temperature of the metal hydride used in the present invention, and Fig. 4 is an explanatory diagram showing an example of the conventional method. It is a diagram. 1 is a low temperature storage tank, 2 and 3 are containers, 4 and 5 are heat transfer paths, 7 is a generated gas line, 12 is a shipping line, 18 is a hydrogen gas flow path, 22 is a correction compressor, 2
3 indicates a hydrogen gas pressure adjustment device.

Claims (1)

[Claims] 1. Two containers are placed in one of two containers that separately contain different types of metal hydrides and are connected to each other through a hydrogen gas flow path.
A heat transfer path for the system is provided, and a shipping line connected to a low temperature storage tank is connected to one side of the heat transfer path, and
A reliquefaction device for low-temperature liquefied gas, characterized in that the other heat transfer path is connected to a generated gas line connected to a low-temperature storage tank, and the hydrogen gas flow path is provided with a hydrogen gas pressure adjustment device.