JP2001263894A - Cryogenic liquid storage facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cryogenic liquid storage facility comprising a cooler which can be replaced by a cooler of large open cooling tower type. SOLUTION: A facility 2 for storing/gasifying/supplying cryogenic liquid, e.g. LNG, is additionally provided with an LNG bypass section 4. A heat exchanger 30 containing intermediate medium 31 exchanges heat between LNG flowing through the LNG bypass section 4 and cooling water for a heat generating unit 57 to rob heat from the cooling water. Furthermore, heat exchanging amount is regulated by operating an LNG flow rate regulation valve 44 based on the water temperature measured by a water temperature meter 60 so that the cooling water can be prevented from freezing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic liquid storage facility, and more particularly, to a cryogenic liquid storage facility provided with a cooling device for cooling surrounding heat-producing equipment by utilizing the cold heat of the cryogenic liquid.

[0002]

2. Description of the Related Art FIG. 3 shows LNG (liquefied natural gas) storage, vaporization and supply equipment as an example of equipment for handling low-temperature liquids. This LNG storage / vaporization / supply facility 101
The main parts of the storage tank 20 for storing LNG, a discharge pump 21 for discharging LNG from the storage tank 20,
LNG delivery pipe 22 for delivering LNG via LNG flow control valves 25 and 26, and LNG delivered by LNG delivery pipe 22.
It is composed of a vaporizer 23 that is supplied with NG and vaporizes it, and a natural gas distribution pipe 24 that distributes the vaporized gas to a power generation facility or the like.

The LNG stored in the storage tank 20
Is delivered in a liquid state to the vaporizer 23, where it is vaporized and supplied to various facilities. In the vaporizer 23, LNG is usually vaporized using the heat of seawater. Therefore, the seawater supply pipe 27 is connected to the vaporizer 23, and by operating the pump 28, the seawater is pumped up and supplied into the vaporizer 23. The pump 28 generates heat during operation and thus needs to be cooled.

[0004] Such LNG storage, vaporization and supply equipment 1
In FIG. 01, in addition to the pump 28, a gas compressor for adjusting the gas pressure in the storage tank 20, an air compressor for supplying compressed air used for the operation of various valves, and the like. Many devices that generate heat when operated are provided. These devices, which are not individually illustrated, are collectively illustrated as the heating device 104 here.
Conventionally, in order to cool such a heat generating device 104, a cooling device 102 that circulates cooling water and removes heat is provided by an LNG.
The storage, vaporization, and supply equipment 101 is provided in association with the equipment. FIG. 3 shows, as a typical example of the conventional cooling device 102, a type in which cooling water is taken out and cooled by a cooling water tower 103.

[0005] The cooling device 102 includes a low-temperature pipe 106 for supplying cooling water to the heat-generating equipment 104 and a cooling water circulating pump 1.
05, a high-temperature pipe 107 through which the hot water is cooled by cooling the heat generating device 104, and a cold water tower 103 that cools the hot water. Cool water tower 1
03 is a fan 108 for air-cooling the cooling water sprayed from the end 107a of the high-temperature pipe 107 and its driving device 10
9, a water tank 110 for receiving the cooled cooling water. The atmosphere is used for heat removal of the cooling water in the cooling water tower 103, and the cooling device is an open-to-atmosphere type cooling device.

[0006]

However, the above-mentioned conventional cooling water tower type cooling device is large and costly, and consumes much power of a fan for supplying heat removal air. It is necessary to take measures against contamination by suspended solids in the air. In some cases, the heating system cooling system may be clogged due to dust, etc .; it is difficult to use antifreeze; therefore, it is necessary to take measures against freezing in winter. There are various problems in running cost and maintenance, for example,

The present invention has been made to solve such a problem, and provides a low-temperature liquid storage facility provided with a cooling device which can be replaced with the above-mentioned conventional open-to-atmosphere type cooling water tower type cooling device. The purpose is to do.

[0008]

According to the first aspect of the present invention,
In a low-temperature liquid storage facility that discharges a low-temperature liquid from a storage tank and supplies the low-temperature liquid to a consumption facility, the low-temperature liquid includes a heat exchanger that performs heat exchange between the low-temperature liquid and a cooling medium, and the heating medium includes a heat exchanger that exists around the cooling medium. It is characterized by comprising a cooling device for cooling.

According to this configuration, a large-scale cooling medium cooling device such as a separately provided cooling water tower is not required in the conventional low-temperature liquid storage facility, and moreover, the cooling medium is more efficiently provided by the low-temperature liquid. More heat can be removed. Further, since heat is removed by the heat exchanger while the cooling medium is sealed, there is no contact between the cooling medium and the atmosphere, and it is easy to use antifreeze as the cooling medium.

According to a second aspect of the present invention, in the low-temperature liquid storage facility according to the first aspect, the flow rate of the low-temperature liquid flowing through the heat exchanger detects a temperature of the cooling medium passing through the heat exchanger. The flow rate is adjusted by the flow rate adjusting means which operates.

In the heat exchanger, when the cooling medium is excessively cooled, the cooling medium freezes and the flow path is closed. However, according to this configuration, the cooling medium is prevented from freezing in the heat exchanger. Since the flow rate of the low-temperature liquid can be adjusted, the heat of the cooling medium can be removed by making maximum use of the low-temperature liquid heat.

The invention described in claim 3 is the first or second invention.
The cryogenic liquid storage facility as described above, wherein the cooling medium is deprived of heat via an intermediate medium having a lower melting point than the cooling medium.

According to this configuration, when it is necessary to reduce the flow rate of the low-temperature liquid in order to prevent the cooling medium from freezing,
The use of an intermediate medium with a lower melting point does not freeze even with more flowing cryogenic liquid. Therefore, the amount of heat removed by the low-temperature liquid can be made larger than when the intermediate medium is not used.

According to a fourth aspect of the present invention, in the low-temperature liquid storage facility according to any one of the first to third aspects, the low-temperature liquid is a liquefied gas, and a vaporizer for vaporizing the liquefied gas;
A delivery pipe for supplying liquefied gas from the storage tank to the vaporizer, and supplying the liquefied gas to the heat exchanger;
This is performed through a bypass pipe branched from the delivery pipe,
The bypass pipe is connected to a portion of the delivery pipe upstream of the vaporizer via the heat exchanger.

According to this configuration, the heat of the cooling medium can be removed without significantly changing the existing piping system. In addition, the liquefied gas that has passed through the heat exchanger is supplied to the vaporizer as in the past, and a part of the gas is vaporized at the time of heat removal, so that a part of the vaporizing action in the vaporizer can be shared.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a low-temperature liquid storage facility according to the present invention will be described below with reference to the drawings. In the following description, the low-temperature liquid will be described as LNG, and the cooling medium of the heat-generating device will be described as water. However, the low-temperature liquid and the cooling medium according to the present invention are not limited thereto, and these are merely examples.

First, the configuration of the low-temperature liquid storage facility 1 will be described with reference to FIG. The low-temperature liquid storage facility 1 is largely composed of a conventional LNG storage / vaporization / supply facility 2 and a cooling device 3 for cooling various heating devices 57 existing in the facility by circulating cooling water. ing. Also,
The cooling device 3 includes an LNG bypass unit 4 that branches from the LNG storage / vaporization / supply equipment 2 and passes LNG, and a heating device 5.
7 and a cooling water circulating device 5 for circulating cooling water.

The LNG storage / vaporization / supply equipment 2 includes a storage tank 20 for storing LNG, a dispensing pump 21 for discharging LNG from the storage tank 20, as in the conventional equipment.
LNG delivery pipe 22 for delivering LNG via LNG flow control valves 25 and 26, and LNG delivered by LNG delivery pipe 22.
A vaporizer 23 that receives NG and vaporizes it, and a natural gas distribution pipe 24 that distributes the vaporized gas to a power generation facility or the like.
It is composed of

In the LNG storage / vaporization / supply facility 2 of the present embodiment, a branch point 41 is provided in the middle of the LNG distribution pipe 22, and an LNG bypass section 4 is formed therefrom. In the LNG bypass unit 4, in order from the branch point 41 side,
Gate valve 42, check valve 43, LNG flow control valve 44, L
The NG heat exchange section 45, the check valve 46, and the cutoff valve 47 are arranged. These are connected by a bypass line 49 and connected again to the LNG delivery pipe 22 at a junction 48.

The two gate valves 42 and 47 are connected to the LNG delivery pipe 22 during maintenance of the LNG bypass section 4.
The NG bypass section 4 can be cut off. The two check valves 43 and 46 are for preventing the backflow of LNG flowing through the LNG bypass unit 4, and
The NG flow control valve 44 is connected to the LN flowing through the bypass pipe 49.
By changing the flow rate of G, the heat exchange amount in the LNG heat exchange section 45 is adjusted. LNG heat exchange unit 4
5 is housed in the heat exchanger 30.

On the other hand, the cooling water circulation device 5 includes a heat exchanger 30
, The heat exchanger is arranged to exchange heat with LNG flowing through the LNG bypass unit 4. The cooling water circulation device 5 includes a cooling water heat exchange unit 51 disposed in the heat exchanger 30.
The low-temperature pipe 52, the water tank 53, the low-temperature pipe 5
4. Cooling water circulation pump 55, low-temperature piping 56, heating equipment 5
7. The circuit goes through a high-temperature pipe 58. In this one-round arrangement, there is no part that needs to be open to the atmosphere,
A closed circuit is also possible.

A water temperature gauge 60 is attached to a low temperature pipe 52 extending from the cooling water heat exchange section 51 to a water tank 53. The water temperature measured by the water temperature gauge 60 is input to a water temperature feedback device 61 including a microcomputer and an actuator,
The water temperature feedback device 61 includes an LNG flow control valve 44.
To work. Thus, the water temperature gauge 60, the water temperature feedback device 61, and the LNG flow control valve 44 constitute an LNG flow control means.

The heat exchanger 30 has one LN as described above.
The G heat exchanging section 45 is arranged on the other side, and the cooling water heat exchanging section 51 is arranged on the other side, and the space between them is filled with the low melting point oil 31 as an intermediate medium.

Next, the operation and effect of the low-temperature liquid storage facility 1 and the cooling device 3 having the above-described configurations will be described. LNG
Is discharged from the storage tank 20 by the discharge pump 21 and enters the vaporizer 23 through the LNG distribution pipe 22, where vaporization is performed using seawater, and the natural gas distribution pipe 24
Sent out to Cutoff valve 42 in LNG bypass section 4
47 is in the open state during normal operation,
From the LNG also flows into the LNG bypass unit 4. LNG
Is transmitted through the check valve 43 and the LNG flow control valve 44 to the LN
G enters the heat exchange section 45, where it deprives the low-melting oil 31 of heat and cools it, and the LNG itself gains heat and partially vaporizes while passing through the check valve 46 at the junction 48, It joins LNG flowing in the LNG delivery pipe 22. At this time, although partial vaporization occurs as described above, there is no problem in the flow, but rather, it partially plays a vaporizing action of the vaporizing device 23, which contributes to improvement of the vaporizing ability.

On the other hand, the cooling water for cooling the heating device 57 is constantly circulating in the cooling water circulating device 5 by the operation of the cooling water circulating pump 55. The cooling water sent to the heat-generating device 57 takes heat here to cool the heat-generating device 57, and at the same time, obtains heat and rises in temperature. The high-temperature cooling water passes through the high-temperature pipe 58 and passes through the heat exchanger 30.
Into the cooling water heat exchanging section 51 inside. Since the low-melting oil 31 cooled by the LNG exists as described above, the heat of the cooling water is taken away, and the temperature of the cooling water decreases.
The low-temperature cooling water enters the water tank 53 via the low-temperature pipe 52, is pumped out of the cooling water circulating pump 55, and is supplied again to the heat generating device 57 to cool the cooling water. By repeating the above cycle, the cooling of the heating device 57 is continued in a favorable state. Since the temperature of the cooling water can be made lower than that of the conventional cooling water tower type, the temperature gradient in the heating device 57 increases, and the cooling efficiency improves.

By the way, depending on the balance between the temperature of the low melting point oil 31 in the heat exchanger 30 and the temperature and flow rate of the cooling water flowing through the cooling water heat exchange section 51, the cooling water freezes and the flow is hindered. there is a possibility. In the present embodiment, in order to prevent such freezing, the water temperature gauge 60
And an LNG flow control valve 44 and a water temperature feedback device 61. Although not shown, the water temperature feedback device 61 is equipped with a microcomputer, and the water temperature measured by the water temperature meter 60 and the appropriate flow rate of LNG are stored in advance. When the water temperature drops from a certain steady state and shifts to the freezing direction, for example, the microcomputer operates the LNG flow control valve 44 in a direction to decrease the LNG flow rate. LNG
Is decreased, the amount of heat taken by the LNG in the heat exchanger 30 is reduced, so that the temperatures of the low melting point oil 31 and the cooling water are increased, and freezing is prevented. Conversely, when the water temperature rises, the microcomputer operates the LNG flow control valve 44 in the flow increasing direction to increase the amount of heat taken from the cooling water. By adjusting the flow rate of LNG in this way, freezing of the cooling water is prevented and the cold heat of the LNG can be utilized to the maximum.

FIG. 2 shows another embodiment according to the present invention.
A low-temperature liquid storage facility 11 having a cooling device 13 that performs cooling of cooling water not in a pipe section but in a water tank section is shown. The configuration thereof is the same as that of the above-described embodiment in that the cooling device 13 includes an LNG bypass unit 14 and a cooling water circulating device 15. However, the cooling device 13 of the present embodiment
In, there is no independent heat exchanger, and the LNG heat exchange unit 45a of the LNG bypass unit 14 is disposed in the water tank 53a of the cooling water circulation device 15. Along with this arrangement, the high-temperature pipe 58a that receives the high-temperature cooling water from the heating device 57 opens in the water tank 53a. Further, the water temperature gauge 60 is disposed so as to detect the water temperature near the LNG heat exchange unit 45a in the water tank 53a.

The cooling operation of the cooling device 13 thus configured is performed by the LNG heat exchange section 45 disposed in the water tank 53a.
a is directly removed from the cooling water. To prevent the cooling water from freezing, the water temperature near the LNG heat exchange unit 45a detected by the water temperature gauge 60 is input to the water temperature feedback device 61, and the LNG heat exchange unit 45a is This is done by adjusting the flowing LNG flow rate. In the cooling device 13 of the present embodiment, L
Since a large amount of cooling water exists around the NG heat exchange unit 45a, a large amount of LNG can be flowed while maintaining a state in which the cooling water is not frozen, and the cooling efficiency is improved.

In the above description, the low-temperature liquid is LNG,
Although the cooling medium of the heating device has been described as water, the low-temperature liquid is not limited to LNG, and the same operation can be performed by LPG or other low-temperature chemicals. Further, in the cooling device included in the present invention, since the cooling medium can be hermetically circulated, it is easy to use antifreeze instead of water as the cooling medium. The use of antifreeze eliminates the need to take special measures as a measure against freezing in winter when installed in cold regions. Also,
Since the flow rate of the cooling LNG can be increased by taking advantage of the fact that it is difficult to freeze in the heat exchange section, there is an advantage that the cooling efficiency is further improved.

Further, the heat-generating equipment to be cooled in the above description is not limited to the equipment existing in the same equipment, and if a piping for circulating a cooling medium can be installed, for example, other adjacent equipment may be used. It may be a heating device existing in the facility.

[0031]

As described above, according to the first aspect of the present invention, it is possible to configure a closed-type cooling device that replaces a conventional open-to-atmosphere cooling device by utilizing the cold heat of a low-temperature liquid. This eliminates the risk of contamination of the cooling medium by airborne substances and clogging of the cooling system for heating equipment, as well as the ability to easily use antifreeze and eliminate the need for measures to prevent winter freezing in cold regions. .

According to the second aspect of the present invention, the flow rate of the low-temperature liquid can be adjusted so that the cooling medium does not freeze in the heat exchanger. It can be performed.

According to the third aspect of the present invention, the use of the intermediate medium having a lower melting point allows more low-temperature liquid to flow, thereby improving the cooling efficiency.

According to the fourth aspect of the present invention, the heat of the cooling medium can be removed without largely changing the existing piping system, and the bypassed liquefied gas is partially vaporized during the heat removal. Therefore, a part of the vaporizing action in the vaporizing device can be shared.

[Brief description of the drawings]

FIG. 1 is an equipment configuration diagram showing one embodiment of a low-temperature liquid storage equipment according to the present invention.

FIG. 2 is an equipment configuration diagram showing another embodiment in which a heat exchange unit is disposed in a cooling water tank.

FIG. 3 is an equipment configuration diagram showing a conventional low-temperature liquid storage equipment provided with an open-to-atmosphere type cold water tower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-temperature liquid storage equipment 2 LNG storage / vaporization / supply equipment 3 Cooling device 4 LNG bypass part 5 Cooling water circulation device 20 Storage tank 22 LNG delivery pipe 23 Vaporizer 30 Heat exchanger 31 Intermediate medium 44 LNG flow control valve 49 Bypass pipe 57 Heating equipment 60 Water temperature gauge 61 Water temperature feedback device

Claims (4)

[Claims] 1. A low-temperature liquid storage facility that discharges a low-temperature liquid from a storage tank and supplies the low-temperature liquid to a consuming facility, comprising: a heat exchanger that exchanges heat between the low-temperature liquid and a cooling medium; A low-temperature liquid storage facility comprising a cooling device for cooling a heat-generating device. 2. The flow rate of the low-temperature liquid flowing through the heat exchanger is adjusted by a flow rate adjusting unit that operates by detecting a temperature of the cooling medium that has passed through the heat exchanger. 2. The cryogenic liquid storage facility according to 1. 3. The low-temperature liquid storage equipment according to claim 1, wherein the heat of the cooling medium is removed via an intermediate medium having a lower melting point than the cooling medium. 4. The cryogenic liquid is a liquefied gas, comprising a vaporizer for vaporizing the liquefied gas, and a delivery pipe for supplying the liquefied gas from the storage tank to the vaporizer, and liquefying the heat exchanger. The supply of gas is performed through a bypass pipe branched from the delivery pipe, and the bypass pipe is connected to a portion of the delivery pipe upstream of the vaporizer via the heat exchanger. The low-temperature liquid storage facility according to any one of claims 1 to 3, characterized in that: