JPS6231756Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention prevents the occurrence of bumping phenomenon at the rising part of the liquid receiving pipe in a low-temperature tank for storing low-temperature saturated liquids such as LNG and LPG. The present invention relates to a device designed to do this.

[Conventional technology]

As shown in Figure 1, low-temperature saturated liquid storage equipment generally receives low-temperature saturated liquids such as LNG and LPG transported by ship from a liquid reception port 1 and passes through a liquid reception pipe 2 to the upper part of a tank 3. It is stored in tank 3. Therefore, in such low-temperature saturated liquid storage equipment, the liquid receiving pipe 2 is often kept filled with the stored liquid via the piping 4 even after receiving the liquid from the ship. This is because if the liquid receiving pipe 2 is emptied, the temperature of the liquid receiving pipe 2 will rise, so the next time liquid is received from the ship, the liquid receiving pipe 2 must be cooled again over time. This is because it will no longer be possible.

[Problem that the invention aims to solve]

However, when the liquid receiving tube 2 is filled with the stored liquid as described above, evaporation occurs inside the liquid receiving tube 2 due to heat entering from the atmosphere, which causes a bumping phenomenon at the rising portion 2a of the liquid receiving tube 2. cause. Therefore, the liquid in the rising part 2a is pushed up by the gas and enters the upper horizontal part 2b of the liquid receiving pipe 2 together with the gas, the gas and liquid are separated at the upper horizontal part 2b, and the gas enters the tank 3. The liquid falls from the upper horizontal portion 2b to the rising portion 2a due to gravity. The rising portion 2a has a large diameter of 500 to 800 mm, and a large amount of liquid is pushed up, so a large amount of liquid falls to the rising portion 2a.
There is a possibility that a water hammer phenomenon may occur in the liquid in the liquid receiving tube 2 due to the liquid falling to the lower part, and vibration may occur in the liquid receiving tube 2. In addition, 2c in FIG. 1 is a lower horizontal part.

The present invention was devised in view of the above-mentioned circumstances, with the purpose of preventing the bumping phenomenon from occurring at the rising portion of the liquid receiving pipe.

[Means for solving problems]

The present invention provides a low-temperature tank equipped with a liquid receiving pipe having a lower horizontal part, a rising part, and an upper horizontal part for receiving low-temperature saturated liquid into the low-temperature tank. or a tube equipped with a heater, and the other end of the small-diameter tube or tube equipped with a heater is connected to a predetermined position below the liquid level of the rising portion of the liquid receiving tube. ing.

[Effect]

In the pipe that connects the lower horizontal part of the liquid receiving pipe and the required position below the liquid level of the riser pipe, the liquid boils faster than the rising part of the liquid receiving pipe and gas is generated. Since the low temperature saturated liquid in the rising section is stirred, bumping of the low temperature saturated liquid in the rising section is prevented. Since the gas generated in the pipe that connects the lower horizontal part of the liquid receiving pipe and the required position below the liquid level of the riser pipe is small, even if boiling occurs in the pipe, bumping will not occur in the riser pipe and there is no danger. do not have.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 2 and 3 show an embodiment of the present invention.

In FIG. 2, the liquid receiving pipe 2 is the liquid receiving port 1.
It is arranged horizontally from to the position immediately in front of tank 3, and then rises from there and extends further horizontally, until tank 3
is led into the tank 3 from the top of the tank. Furthermore, as shown in detail in FIG. 3, the distance between the required position on the tank 3 side of the lower horizontal part 2c of the liquid receiving pipe 2 and the required position below the liquid level of the rising part 2a is larger than the diameter of the liquid receiving pipe 2. They are connected by a small diameter pipe 5.

The small diameter pipe 5 has a smaller diameter than the liquid receiving pipe 2 (for example, when the diameter of the liquid receiving pipe 2 is 500 to 800 mm, the diameter of the small diameter pipe 5 is about 50 to 100 mm). Further, a heat insulating material 6 is attached to the outer periphery of the liquid receiving pipe 2.

The reason why a small diameter pipe is used for the pipe 5 is as follows. That is, when the diameter of the tube 5 is increased, the diameter of the tube 5 is increased.
Due to the bumping phenomenon of the low-temperature saturated liquid in the tube 5, the amount of liquid pushed up by the gas generated in the tube 5 and in the liquid receiving tube 2 increases, and the gas and liquid move to the upper horizontal part 2b of the liquid receiving tube 2. Since the gas and liquid are separated in the upper horizontal part 2b, there is a risk that the liquid will fall from the upper horizontal part 2b to the rising part 2a and water hammer phenomenon will occur in the liquid in the liquid receiving pipe 2, as in the conventional case. This is because there is no need to increase the diameter because it is not a liquid receiving tube, and it is necessary to boil the liquid in the tube 5 before the liquid receiving tube 2.

In addition, the rising portion 2a of the liquid receiving pipe 2 of the small diameter pipe 5
The mounting position for the product is determined as follows. That is, when the ratio H/D of the inner diameter D of the tube containing the low-temperature saturated liquid and the height H from the bottom of the tube to the low-temperature saturated liquid level is less than a certain value α (for example, D = 500 mm
In the case of H/D<30), even if heat is input into the pipes from the atmosphere, the heated liquid simply moves to the liquid surface and evaporates from the liquid surface, so no bumping phenomenon occurs. However, if H/D exceeds a certain value, that is, if the height of the liquid becomes higher than the inner diameter of the tube, even if heat enters the tube from the atmosphere and the liquid temperature rises, the rising part will not reach the liquid level. The liquid cannot move to the surface, and the liquid temperature rising portion remains in the liquid, which causes bumping phenomenon. Therefore, the mounting height H' of the small diameter pipe 5 relative to the rising portion 2a of the liquid receiving pipe 2 may be set to a position below H'<αD. For example, if the inner diameter of the rising portion 2a of the liquid receiving pipe 2 is 500 mm, H'<15 m may be satisfied.

According to the above configuration, once the reception of the low-temperature saturated liquid is finished and the liquid receiving port 1 is closed to leave the liquid receiving pipe 2 and the small diameter pipe 5 filled with the stored liquid, it is possible to remove the liquid from the atmosphere. The liquid receiving pipe 2
The temperature of the liquid inside the small-diameter pipe 5 rises, and the temperature of the liquid inside the small-diameter pipe 5 also rises due to heat entering from the atmosphere. At this time, since the small diameter pipe 5 has a smaller diameter than the liquid receiving pipe 2, the temperature of the liquid in the small diameter pipe 5 rises quickly, the liquid evaporates, and bumping occurs at the rising portion 2a of the liquid receiving pipe 2. Beforehand, boiling occurs in the small diameter tube 5. The liquid in this raised portion 2a is in a supercooled state because it is pressurized by the wave crest at its bottom.

When boiling occurs in the small diameter pipe 5, the gas generated by the evaporation of the liquid and the liquid pushed by the gas enter the rising part 2a of the liquid receiving pipe 2 from the small diameter pipe 5 and rise up the rising part 2a. , the liquid above the small diameter pipe 5 connection part in the rising part 2a is stirred. As a result, the temperature of the stirred liquid becomes uniform, and the temperature of the liquid in the rising portion 2a of the liquid receiving tube 2 does not rise to the point where it boils.
In addition, since the amount of gas generated in the small diameter pipe 5 is small, even if this gas and the liquid pushed by the gas enter the rising part 2a of the liquid receiving pipe 2, the liquid in the rising part 2a is stirred as described above. However, the liquid in the rising portion 2a will not rise to the upper horizontal portion 2b. Therefore, the liquid level in the rising portion 2a of the liquid receiving pipe 2 changes slightly due to stirring, and the rising portion 2a
Bumping can be prevented from occurring within the liquid receiving tube 2, and the liquid will not fall from the upper horizontal portion 2b side into the rising portion 2a of the liquid receiving tube 2, so water hammer may not occur on the liquid surface within the liquid receiving tube 2. do not have. Further, below the small diameter pipe 5 connection part of the rising part 2a of the liquid receiving pipe 2, the height H' of the small diameter pipe 5 connection part is H/D=α.
Since the height is lower than the height determined by , bumping does not occur in the liquid below the small diameter pipe 5 connection part of the rising part 2a.

Furthermore, since the liquid discharged from the small diameter pipe 5 to the rising part 2a of the liquid receiving pipe 2 does not flow back from the rising part 2a to the small diameter pipe 5, water hammer phenomenon does not occur in the liquid in the small diameter pipe 5. do not have.

4 and 5 show other embodiments of the present invention, in which a lower horizontal portion 2c and a rising portion 2 of the liquid receiving pipe 2 are shown.
a is connected by a tube 7. A heater 8 is installed in the middle of the tube 7 to heat the low-temperature saturated liquid in the tube 7 with a heating fluid. 9 is a fluid inlet, 1
0 is a fluid outlet, and 11 is a heat insulating material. The height H' of the connection part to the rising part 2a of the pipe 7 is the same as above.
The height is determined by H'<αD.

Due to the heating medium supplied to the heater 8, the low temperature saturated liquid in the tube 7 rises in temperature faster than the low temperature saturated liquid in the rising part 2a of the liquid receiving tube 2 and boils, generating gas. The liquid pushed by enters the rising part 2a of the liquid receiving pipe 2 from the pipe 7, ascends the rising part 2a, and enters the small diameter pipe 5 in the rising part 2a.
Stir the liquid above the connection a. As a result, the temperature of the stirred liquid becomes uniform as in the case of FIGS. 2 and 3, and the temperature of the liquid in the rising portion 2a of the liquid receiving tube 2 does not rise to the extent that it evaporates. Compared to the rising part 2a of the liquid receiving pipe 2, the volume is smaller, the amount of heating is lower, and the amount of gas generated is small, so the liquid in the rising part 2a rises to the upper horizontal part 2b with only a slight movement of the liquid level. Therefore, it is possible to prevent bumping from occurring at the rising portion 2a. Further, below the pipe 7 connection part of the rising part 2a of the liquid receiving pipe 2, the height H' of the pipe 7 connection part is lower than the height determined from H/D=α as described above. Bumping does not occur in the liquid below the 7 connection.

Further, since the liquid discharged from the pipe 7 to the rising part 2a of the liquid receiving pipe 2 does not flow back from the rising part 2a to the pipe 7, no water hammer phenomenon occurs in the pipe 7.

Figure 6 shows another example of the heater applied to the present invention.
A fin 12 is fixed to the outer periphery of the small diameter pipe 5 as a heater. Even with this configuration, bumping of the rising portion 2a of the liquid receiving pipe 2 can be prevented as in each of the embodiments described above.

7 and 8 show other embodiments of the present invention, in which piping is provided from the lower part of the tank 3 shown in FIGS. 2 and 4 for guiding the stored liquid to the vicinity of the liquid receiving port 1 of the liquid receiving pipe 2 13 are arranged.

With such a configuration, when boiling occurs in the small diameter pipe 5 or the pipe 7, the liquid therein vaporizes and a flow also occurs in the liquid receiving pipe 2, so that the inside of the tank 3 is removed from the pipe 13. A cold liquid is introduced into the liquid receiving tube 2. Thereby, the liquid receiving pipe 2 is cooled.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes may be made without departing from the gist of the present invention.

[Effect of idea]

According to the bumping prevention device for the rising part of the liquid receiving pipe in a low-temperature tank of the present invention, bumping does not occur at the rising part of the liquid receiving pipe, and therefore the water hammer phenomenon does not occur in the liquid in the liquid receiving pipe. LPG,
Various excellent effects can be achieved, such as ensuring the safety of storage equipment for low-temperature saturated liquids such as LNG.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional low-temperature saturated liquid storage facility.
Fig. 2 is an explanatory diagram of an embodiment of the bumping prevention device for the rising part of the liquid receiving pipe in a low-temperature tank of the present invention, Fig. 3 is an enlarged explanatory diagram of the vicinity of the small diameter pipe in Fig. 2, and Fig. 4 5 is an explanatory diagram of another embodiment of the bumping prevention device of the rising part of the liquid receiving pipe in a low-temperature tank according to the present invention, FIG. The figure is an enlarged explanatory view of another example near the part of the tube where the heater is attached in Figure 4,
FIG. 7 is an explanatory diagram of still another example of the bumping prevention device of the rising part of the liquid receiving pipe in the low temperature tank of the present invention;
FIG. 8 is an explanatory view of yet another example of the bumping prevention device for the rising portion of the liquid receiving pipe in the low temperature tank of the present invention. In the figure, 1 is a liquid receiving port, 2 is a liquid receiving pipe, 2a is a rising part, 2b is an upper horizontal part, 2c is a lower horizontal part, 5 is a small diameter pipe, 7 is a pipe, 8 is a heater, 12 is a fin, 13 indicates piping.

Claims (1)

[Scope of utility model registration request] In a low-temperature tank equipped with a liquid receiving pipe having a lower horizontal part, a rising part, and an upper horizontal part for receiving low-temperature saturated liquid into the low-temperature tank, the lower horizontal part of the liquid receiving pipe is provided with a pipe having a smaller diameter than the liquid receiving pipe or One end of a tube equipped with a heater is connected to the tube, and the other end of the small-diameter tube or the tube equipped with a heater is connected to a predetermined position below the liquid level of the rising portion of the liquid receiving tube. Bumping prevention device for the rising part of the liquid receiving pipe in a tank.