JPS58180898A - Method and apparatus for cooling low-temperature piping - Google Patents

Abstract

PURPOSE:To cool through utilizing latent heat and save operating power cost, by a method wherein automatically operated valves and a gas separator are provided in a pipe connected to a low-temperature liquid storing tank, and a gas layer in the gas separator and that in the tank are connected to each other. CONSTITUTION:The automatically operated valves 7, 8 are closed to interrupt the communication between a liquid contained in a receiving pipe 2 and that contained in the low-temperature liquid storing tank 1, a pump 3 is stopped, an automatic controlling valve 11 is controlled by a pressure controller 12 for the gas separator 5 to communicate the gas layer in the tank 1 and that in the separator 5 to each other through a pipe 6, thereby equalizing the pressure in the tank 1 and that in the separator 5, and the liquid in the pipe 2 is maintained at a saturation pressure substantially equal to that in the tank 1. Consequently, a gas is generated in the pipe 2 due to an input of heat from the exterior, the gas enters the gas separator 5, and is then fed into the tank 1 through the pipe 6. In this case, when the quantity of the liquid in the pipe 2 is reduced due to evaporation, necessity to supply the liquid is detected through a signal from a temperature detector 14 connected to the pipe 2 or through the liquid level in the separator 5, the valve 11 is changed over to perform only a liquid level control, then the automatic valves 7, 8 are opened, and the pump 3 is operated to supply the liquid into the pipe 2.

Description

Detailed Description of the Invention The present invention relates to a method and apparatus for cooling pipes for receiving or shipping low-temperature liquids such as LNG or LPG. The present invention relates to a cooling method and device for low-temperature piping that utilizes the latent heat of pipes to reduce equipment costs and operating costs and to stably perform cooling.

It is technically necessary to keep piping for receiving or shipping low-temperature liquids such as LNG constantly cooled. This is because it is necessary to keep such piping available for use at any time, and to reduce thermal stress applied to the piping by eliminating the need for cooling down and reducing temperature changes in the piping.

Conventionally, the pipe cooling method has been to circulate the liquid in the low-temperature liquid storage tank using a pump to cool it.

However, this cooling is mainly performed using sensible heat generated by temperature changes in the low-temperature liquid, so if the piping is long, a large amount of liquid must be circulated, which increases equipment and operating costs and results in insufficient cooling. This may give rise to the question of sufficiency.

The present invention eliminates the above-mentioned conventional problems, performs cooling mainly by utilizing latent heat, significantly reduces equipment costs and pump operating costs, and enables reliable cooling.

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

The figure shows the case of receiving low-temperature liquid from an LNG or LPG ship, where (1) is a low-temperature liquid storage tank, (2)
is the low-temperature liquid receiving pipe, and when shipping low-temperature liquid, it becomes the shipping pipe. (3) is the coolant delivery pump to the receiving pipe (2), (4) is the coolant delivery pipe, and the low temperature liquid storage tank (1
) and the receiving pipe (2). (5) is a gas separator connected in the middle of the receiving pipe (2).
) installed in a higher position.

(6) stores the gas separated by the gas separator (5) in the storage tank (1
), (7) is the receiving pipe (2)
(8) is an automatic remote control valve installed in pipe (4), and (9) is a manual valve installed on the ship side of receiving pipe (2), which is closed when not receiving liquid. Make sure that you are αQ is the loading arm, 0υ is the gas pipe (
(6) is an automatic control valve installed in the middle of the gas separator (2).
5) is a pressure controller that controls the automatic control valve αυ so that the pressure in the storage tank (1) is the same as the pressure in the storage tank (1), and is attached to the gas separator (5). α4 has liquid gas piping (6)
This liquid level controller is attached to the gas separator (5) to control the automatic control valve αυ so that the gas does not flow into the gas separator (5).

The device of the present invention has the above-mentioned configuration, and when no liquid is being received, the automatic remote control valves (7) and (8) are closed, the manual valve (9) is closed, and the low-temperature liquid is injected into the receiving pipe (2). satisfy. This ensures that the receiving pipe (2) is always cooled by the low temperature liquid. However, since heat intrudes into the receiving pipe (2) from the outside, this is done automatically and remotely as follows, but the operation is divided into the following two steps.

■ First, as a first step, the automatic remote control valve (7) and (
8) to cut off the communication between the liquid in the receiving pipe (2) and the liquid in the storage tank (1) to prevent the liquid pressure in the storage tank (1) from reaching the receiving pipe (2), and then close the pump (3). ) driving <,,,<
5yl-f;E>. Yes, fj7 no. (52, The attached pressure controller (6) controls the automatic control valve 0υ to connect the gas layer in the storage tank (1) and the gas separator (5) via the gas pipe (6), and connects the storage tank ( By controlling the pressure in the gas separator (5) to be the same as the pressure in the receiving pipe (2), the liquid in the receiving pipe (2) is maintained at approximately the same saturation pressure as in the storage tank (1). ), gas is easily generated due to heat input from the outside, and the generated gas enters the gas separator (5), is separated from the liquid, and then passes through the gas pipe (6) to the storage tank (1). At this time, since the gas separator (5) is installed at a higher position than the receiving pipe (2), the gas generated in the receiving pipe (2) can easily enter the gas separator (5). Also gas separator (
When the gas separated from the liquid in step 5) flows into the storage tank (1), the liquid level controller α■ controls the automatic control valve (1υ) so that the liquid does not flow into the gas pipe (6).

■ Next, as a second step, the above-mentioned receiving pipe (2) generates gas due to heat input from the outside, and when the liquid in the receiving pipe (2) decreases due to evaporation, it is automatically replenished. . That is, when the liquid in the receiving pipe 2) decreases due to evaporation, it is sensed whether replenishment is necessary or not based on the temperature sensor αΦ connected to the receiving pipe (2) or the liquid level of the gas separator (5).

When it is necessary to replenish liquid to the receiving pipe (2), switch the automatic control valve 0) to liquid level control only, open the automatic remote control valves (7) and (8), and then switch the pump (3) to the automatic remote control valve (7) and (8). drive,
Replenish the liquid into the receiving pipe (2). This operation is continued until the remaining liquid in the receiving pipe (2) is flushed into the storage tank (1) and the gas separator (5) is further filled with liquid to a predetermined position.

Cooling of the receiving pipe (2) is ensured by performing the operations in the above two steps alternately.

Note that the gas pipe (6) may be connected to a gas return pipe that is generally installed in parallel with the liquid receiving pipe (2), and the gas separator (5) is connected to the gas return pipe of the liquid receiving pipe (2). Multiple units may be provided in consideration of the separation function. Further, in the above embodiment, the receiving pipe (2) is illustrated, but the same applies to the shipping pipe.

As described above, according to the present invention, (1) When the liquid in the pipe evaporates due to heat from the outside, the latent heat generated during this evaporation mainly absorbs the heat from the outside. Compared to conventional methods, less low-temperature liquid is sent from the storage tank to the piping, and operating power costs are significantly reduced.

(11) Since the liquid in the piping is maintained at approximately the same saturation pressure as the liquid in the storage tank, the piping is reliably cooled.

It can produce excellent effects such as

[Brief explanation of drawings]

The figure is an explanatory diagram showing the configuration of the apparatus of the present invention. (1)...Low temperature liquid storage tank, (2)...Reception piping, (5
)...Gas separator, (6)...Gas piping, (7) (
8)...Automatic remote control valve, (9)...Manual valve, 0υ
... Automatic control valve, (2) ... Pressure side device, 03
...Liquid level controller, a41...Temperature detector. Patent applicant Ishikawajima-Harima Heavy Industries Co., Ltd. Patent applicant agent procedure amendment, written May 28, 1980 Commissioner of the Japan Patent Office Shima 1) Haruki Tono 1 Indication of case 1981 Patent application No. 62065 2 Name of the invention Patent applicant: 2-2-1 Otemachi, Chiyoda-ku, Tokyo (009) Ishikawajima-Harima Heavy Industries Co., Ltd. 4, Agent: 3-5 Uchikanda, Chiyoda-ku, Tokyo Figure 3 Contents of surface 6 correction

Claims (1)

[Claims] l) A receiving or shipping pipe connected to a low-wetting liquid storage tank is filled with a low-wetting liquid to cut off communication between the liquid in the pipe and the liquid in the storage tank, and then the above-mentioned The gas layer of the gas separator connected to the piping is connected to the gas layer of the storage tank to maintain the saturation pressure of the liquid in the piping almost the same as that of the liquid in the storage tank. A cooling method for low-temperature piping, characterized in that the liquid is absorbed by the latent heat generated during evaporation to cool the piping, and then, when the liquid in the piping decreases due to the evaporation, the liquid in the storage tank is replenished into the piping. 2) In the middle of the receiving or shipping piping connected to the low-temperature liquid storage tank, install an automatic operating valve to replenish the liquid in the storage tank into the piping or to cut off the communication between the liquid in the storage tank and the piping. , A gas separator that separates gas and liquid is connected to the piping, and the gas separator and the gas layer of the storage tank are connected by gas piping, so that the liquid in the storage tank and the liquid in the piping are at approximately the same saturation pressure. A cooling device for low-temperature piping, characterized in that the gas separator and the gas piping are equipped with a device for maintaining the temperature as follows.