NL2017593B1

NL2017593B1 - Gas vaporizer

Info

Publication number: NL2017593B1
Application number: NL2017593A
Authority: NL
Inventors: Sumida Yuji; Yoshida Tatsuo
Original assignee: Kobe Steel Ltd
Priority date: 2015-10-14
Filing date: 2016-10-10
Publication date: 2019-04-25
Also published as: JP2017075633A; KR102084549B1; CN107014222B; KR20170044042A; CN107014222A; JP6420223B2; NL2017593A

Abstract

Provided is a gas vaporizer including a plurality of panels arranged at intervals and each having a plurality of heat transfer tubes, a plurality of troughs which supply a heating medium to the heat transfer tubes of each of the panels, a heating medium supply unit which supplies the heating medium to each of the troughs, a receiver which receives the heating medium below each of the panels, and a bypass flow path through which a part of the heating medium is guided from the heating medium supply unit to the receiver without passing along any of the heat transfer tubes. The bypass flow path extends from the heating medium supply unit to the receiver at a position away from the heat transfer tubes.

Description

Technical Field

The present invention relates to a gas vaporizer.

Background Art

Conventionally, a gas vaporizer (ORV) which vaporizes a low-temperature liquefied gas such as a liquefied natural gas (LNG) using a heating medium such as seawater has been known. For example, Japanese Unexamined Patent Publication No. 2010-53932 discloses a gas vaporizer including a plurality of panels, an LNG manifold which supplies a liquefied natural gas (LNG) to each of the panels, a plurality of troughs, a seawater manifold which supplies seawater as a heating medium, and a plurality of branched supply tubes connecting the seawater manifold and the individual troughs.

Each of the panels has a plurality of heat transfer tubes arranged along a specified direction. Each of the heat transfer tubes causes heat exchange between the LNG flowing in the heat transfer tube and the seawater flowing along the outer surface of the heat transfer tube to heat the LNG. The plurality of panels are disposed to be arranged at intervals along an arrangement direction orthogonal to the specified direction. The individual troughs are disposed at positions which are on both sides of each of the panels in the arrangement direction and between which the panel is interposed. The seawater manifold supplies seawater (heating medium) to each of the branched supply tubes. Each of the branched supply tubes supplies the seawater supplied from the seawater manifold to the trough. The seawater that has overflown from each of the troughs flows down along the outer surface of each of the heat transfer tubes of the panels to be received by a receiver provided below each of the panels, thus forming a seawater pond.

There is a case where, in such a gas vaporizer, it is required to set the temperature difference between the temperature of the seawater supplied to the seawater manifold and the temperature of the seawater discharged from the receiver to a value of not more than a prescribed value. As a result, in Japanese Unexamined Patent Publication No. 2010-53932, a temporary accumulation means (subordinate tube) which temporarily accumulates the seawater that has overflown from the outermost trough is provided outside the outermost one of the plurality of troughs which is provided outermost in the arrangement direction described above. The seawater that has overflown from the temporary accumulation means directly reaches the receiver without passing along any of the heat transfer tubes. That is, in Japanese Unexamined Patent Publication No. 2010-53932, the temporary accumulation means is provided outside the outermost trough to inhibit the temperature difference from becoming not less than the prescribed value.

In the gas vaporizer described in Japanese Unexamined Patent Publication No. 2010-53932, the temporary accumulation means is provided outside the outermost trough provided outermost in the arrangement direction among the plurality of troughs. As a result, the enlargement of the vaporizer in the arrangement direction is inevitable. Note that this problem may similarly arise even in the case where a medium (such as warm water) other than seawater is used as a heating medium.

Summary of Invention

An object of the present invention is to provide a gas vaporizer which allows a temperature difference in heating medium to fall within a range of not more than a prescribed value, while avoiding a size increase in the direction in which a plurality of panels are arranged. A gas vaporizer according to an aspect of the present invention is a gas vaporizer which heats a low-temperature liquefied gas using a heating medium to vaporize the low-temperature liquefied gas. The gas vaporizer includes a plurality of panels each having a plurality of heat transfer tubes arranged along a specified direction, the plurality of panels being arranged at intervals along a direction intersecting the specified direction, a plurality of troughs arranged at intervals along an arrangement direction in which the plurality of panels are arranged to supply the heating medium to the heat transfer tubes of each of the panels, a heating medium supply unit which supplies the heating medium to each of the troughs, a receiver which receives the heating medium below each of the panels, and a bypass flow path through which a part of the heating medium is guided from the heating medium supply unit to the receiver without passing along any of the heat transfer tubes. Each of the heat transfer tubes causes heat exchange between the low-temperature liquefied gas flowing in the transfer tube and the heating medium flowing along an outer surface of the heat transfer tube to heat the low-temperature liquefied gas. The bypass flow path extends from the heating medium supply unit to the receiver at a position away from the heat transfer tubes.

Brief Description of Drawings

Fig. 1 is a perspective view of a gas vaporizer in a first embodiment of the present invention;

Fig. 2 is a schematic diagram of a configuration of the gas vaporizer shown in Fig. 1;

Fig. 3 is a schematic side view of the gas vaporizer shown in Fig. 1; Fig. 4 is a view taken along the line IV-IV in Fig. 3; and Fig. 5 is a schematic side view of a gas vaporizer in a second embodiment of the present invention.

Description of Embodiments

Referring to the drawings, the following will describe preferred embodiments of the present invention. (First Embodiment)

Referring to Figs. 1 to 4, a description will be given of a gas vaporizer in. a first embodiment of the present invention.

This gas vaporizer heats a low-temperature liquefied gas using a heating medium to vaporize the low-temperature liquefied gas. In the present embodiment, as the low-temperature liquefied gas, a liquefied natural gas (LNG) is used and, as the heating medium, seawater is used. That is, the gas vaporizer is a so-called open-rack vaporizer (ORV) which causes heat exchange between the LNG and seawater to vaporize the LNG.

As shown in Fig. 1, the gas vaporizer includes a plurality of panels 10, an installation chamber 30, a plurality of troughs 40, a heating medium supply unit 50, and a bypass flow path 60.

Each of the panels 10 causes heat exchange between the LNG and the seawater to vaporize the LNG. Specifically, each of the panels 10 has a plurality of heat transfer tubes 12 arranged along a specified direction, a lower header 14, and an upper header 16. The plurality of panels 10 are disposed to be arranged at intervals along a direction orthogonal to the specified direction. On both sides of each of the panels 10, corridors C where an inspector is to walk are provided. Each of the corridors C has a shape extending along the specified direction at a position apart from each of the panels 10.

Each of the heat transfer tubes 12 causes heat exchange between the LNG flowing in the heat transfer tube 12 and the seawater flowing along the outer surface of the heat transfer tube 12 to heat the LNG.

The lower header 14 is connected to the lower end portion of each of the heat transfer tubes 12 so as to be able to supply the LNG into the heat transfer tube 12 from below. To one end portion of each of the lower headers 14, an LNG supply manifold 20 which supplies the LNG to the lower header 14 is connected. To the LNG supply manifold 20, the LNG is supplied through an LNG supply unit 22.

The upper header 16 is connected to the upper end portion of each of the heat transfer tubes 12 so as to allow the natural gas (NG) that have flown out of the respective upper portions of the individual heat transfer tubes 12 to join together. To one end portion of each of the upper headers 16, an NG joining manifold 24 which allows the NG that have flown out of the upper headers 16 to join together is connected. The NG that have joined together in the NG joining manifold 24 are collected through an NG collection unit 26.

The installation chamber 30 has a shape surrounding each of the panels 10. Specifically, the installation chamber 30 has a side wall 32 covering the periphery of each of the panels 10 and a receiver 34 which closes the lower portion of the side wall 32 and also receives seawater below each of the panels 10. Note that the LNG supply manifold 20 and the NG joining manifold 24 are disposed outside the side wall 32.

Each of the troughs 40 supplies seawater to the heat transfer tubes 12 of each of the panels 10. The troughs 40 are arranged at intervals along the arrangement direction in which the plurality of panels 10 are arranged. In the present embodiment, the troughs 40 are disposed at positions which are on both sides of each of the panels 10 in the arrangement direction and between which the panel 10 is interposed. As shown in Figs 1, 3, and 4, the troughs 40 are disposed at the positions adjacent to the respective upper portions of the heat transfer tubes 12. Each of the troughs 40 is formed in the shape of an upwardly open box. That is, the seawater that has overflown from the opening in the upper portion of each of the troughs 40 flows down along the outer surface of each of the heat transfer tubes 12. The seawater that has flown down along the outer surface of each of the heat transfer tubes 12 is received by the receiver 34 and then discharged from a discharge line L2 through the outlet (the illustration thereof is omitted) formed in the receiver 34.

The heating medium supply unit 50 supplies the heating medium to each of the troughs 40. Specifically, the heating medium supply unit 50 has a plurality of distribution headers 52 which distribute seawater to the individual troughs 40 and a heating medium manifold 54 which supplies the heating medium to each of the distribution headers 52. In the present embodiment, seawater is used as the heating medium. Accordingly, the heating medium supply unit 50 is hereinafter referred to as the seawater supply unit 50 and the heating medium manifold 54 is hereinafter referred to as the seawater manifold 54.

As shown in Figs. 1 and 3, each of the distribution headers 52 is connected to the lower portion of each of the troughs 40. Specifically, each of the distribution headers 52 has a horizontal portion 52a extending generally horizontally and a connection portion 52b connecting the horizontal portion 52a to the lower portion of the trough 40. As shown in Fig. 1, the upstream portion of each of the distribution headers 52 is located outside the side wall 32. In each of the distribution headers 52, an open/close valve VI having an adjustable aperture is provided.

The seawater manifold 54 is connected to the upstream end portion of each of the distribution headers 52. The seawater manifold 54 is disposed outside the side wall 32. The seawater manifold 54 is placed in a position in which the center axis of the seawater manifold 54 is generally horizontal. To the seawater manifold 54, seawater is supplied from a seawater line LI through a seawater inlet 56 provided in the seawater manifold 54.

The bypass flow path 60 is a flow path through which seawater is guided from the seawater supply unit 50 directly to the receiver 34 without passing along any of the heat transfer tubes 12. The bypass flow path 60 extends from the seawater supply unit 50 to the receiver 34 at a position away from the heat transfer tubes 12. Note that the “a position away from the heat transfer tubes 12” means a position where the bypass flow path 60 is away from the heat transfer tubes 12 to such a degree that heat exchange does not occur between the LNG flowing in the heat transfer tube 12 and the seawater flowing in the bypass flow path 60. In the present embodiment, the bypass flow path 60 has a shape extending from the seawater manifold 54 toward the receiver 34 through the side wall 32. The bypass flow path 60 has a first bypass tube 61 and a second bypass tube 62 which extend from the mutually different portions of the seawater manifold 54 toward the receiver 34. As shown in Fig. 4, the respective upstream end portions of the bypass tubes 61 and 62 are connected to the lower portion of the seawater manifold 54. The respective downstream end portions of the bypass tubes 61 and 62 are located in the vicinity of the receiver 34. In each of the bypass tubes 61 and 62, an open/close valve V2 having an adjustable aperture is provided.

Next, a description will be given of the operation of the gas vaporizer described heretofore.

From the seawater line LI to the seawater manifold 54, seawater is supplied while, to the LNG supply manifold 20, the LNG is supplied. The seawater supplied to the seawater manifold 54 flows into each of the troughs 40 through each of the distribution headers 52. Then, the seawater that has overflown from the troughs 40 flows down along the outer surfaces of the heat transfer tubes 12 of each of the panels 10 to be received by the receiver 34 and discharged from the discharge line L2. On the other hand, the LNG supplied to the LNG supply manifold 20 flows into the plurality of heat transfer tubes 12 connected to the lower headers 14 through the individual lower headers 14. The LNG is heated by the seawater flowing along the outer surface of each of the heat transfer tubes 12 to be vaporized (become the NG). The NG is collected through each of the upper headers 16 and the NG joining manifold 24.

There is a case where it is required to set the temperature difference between the temperature of the seawater supplied from the seawater line LI to the seawater manifold 54 and the temperature of the seawater discharged into the discharge line L2 through the receiver 34 to a value of not more than a prescribed value. In the present embodiment, a part of the seawater supplied to the seawater manifold 54 is guided to the receiver 34 through each of the bypass tubes 61 and 62 without passing through any of the heat transfer tubes 12. As a result, it is possible to omit a temporary accumulation means (means disposed outside the outermost trough to temporarily accumulate the heating medium) as used conventionally. This allows the temperature difference in seawater to fall within a range of not more than the prescribed value, while avoiding a size increase in the direction in which the plurality of panels 10 are arranged.

Also, in the present embodiment, each of the bypass tubes 61 and 62 has a shape extending from the seawater manifold 54 toward the receiver 34. In this form, a part of seawater flows from the seawater manifold 54 located upstream of each of the distribution headers 52 toward the receiver 34. Accordingly, the diameter of each of the distribution headers 52 located downstream of the seawater manifold 54 can be set to a value which allows, of the total amount of seawater supplied to the seawater manifold 54, the seawater in an amount required for each of the troughs 40 (required for heat exchange in each of the panels 10) to be supplied to each of the troughs 40. This suppresses an increase in the diameter of each of the distribution headers 52.

Each of the bypass tubes 61 and 62 has a shape extending from the lower portion of the seawater manifold 54 toward the receiver 34. This suppresses the deposition of mud or the like in the seawater manifold 54 and thus reduces a maintenance operation for the seawater manifold 54. (Second Embodiment)

Next, a description will be given of a gas vaporizer in a second embodiment of the present invention with reference to Fig. 5. Note that, in the second embodiment, the description will be given only of the portion thereof different from that of the first embodiment and a description of the same structure, function, and effect as those of the first embodiment is omitted.

In the present embodiment, the bypass flow path 60 is connected to downstream end portions 52c of the distribution headers 52. Note that the downstream end portions 52c of the distribution headers 52 indicate the parts of the horizontal portions 52a which are located downstream of the one of the plurality of connection portions 52b connected to the horizontal portions 52a which is located most downstream. The bypass flow path 60 has a plurality of bypass tubes 64 each having a shape extending from the downstream end portion 52c of each of the distribution headers 52 toward the receiver 34. Each of the bypass tubes 64 has a shape extending downward from the lower portion of the downstream end portion 52c of the distribution header 52 toward the receiver 34 at a position away from the corridors C. Note that, in Fig. 5, the illustration of the corridors C is omitted.

In the present embodiment, a part of the seawater that has flown from the seawater manifold 54 into each of the distribution headers 52 flows toward the receiver 34 through the bypass tube 64 connected to the downstream end portion 52c of the distribution header 52. This suppresses the occurrence of seawater stagnation in the downstream end portion 52c and thus reduces the load of a maintenance operation for the end portion 52c.

This also suppresses the deposition of mud or the like in the downstream end portion 52c and thus further reduces the load of the maintenance operation for the end portion 52c.

Note that the present embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description of the embodiments, and all changes which come within the means and range of equivalency of the claims are therefore intended to be embraced therein.

For example, in the first embodiment, each of the bypass tubes 61 and 62 may also have a shape extending from the portion (such as the side portion or the upper portion) of the seawater manifold 54 which is other than the lower portion thereof toward the receiver 34. Likewise, in the second embodiment, each of the bypass tubes 64 may also have a shape extending from the portion (such as the side portion or the upper portion) of each of the distribution headers 52 which is other than the lower portion thereof toward the receiver 34.

Also, in the first embodiment, the bypass flow path 60 may have one bypass tube or three or more bypass tubes.

Also, in the second embodiment, each of the bypass tubes 64 may have a shape extending from the portion of each of the distribution headers 52 which is located outside the side wall 32 toward the receiver 34 through the side wall 32. It is sufficient for the bypass flow path 60 to have at least one bypass tube 64.

The following is the outline of the foregoing embodiments.

The gas vaporizer in each of the foregoing embodiments is a gas vaporizer which heats a low-temperature liquefied gas using a heating medium to vaporize the low-temperature liquefied gas. The gas vaporizer includes a plurality of panels each having a plurality of heat transfer tubes arranged along a specified direction, the plurality of panels being arranged at intervals along a direction intersecting the specified direction, a plurality of troughs arranged at intervals along the arrangement direction in which the plurality of panels are arranged to supply the heating medium to the heat transfer tubes of each of the panels, a heating medium supply unit which supplies the heating medium to each of the troughs, a receiver which receives the heating medium below each of the panels, and a bypass flow path through which a part of the heating medium is guided from the heating medium supply unit to the receiver without passing through any of the heat transfer tubes. Each of the heat transfer tubes causes heat exchange between the low-temperature liquefied gas flowing in the transfer tube and the heating medium flowing along an outer surface of the heat transfer tube to heat the low-temperature liquefied gas. The bypass flow path extends from the heating medium supply unit to the receiver at a position away from the heat transfer tubes.

In this gas vaporizer, the part of the heating medium supplied to the heating medium supply unit is guided to the receiver through the bypass flow path without passing through any of the heat transfer tubes. As a result, it is possible to omit a temporary accumulation means (means disposed outside the outermost trough to temporarily accumulate the heating medium) as used conventionally. This allows a temperature difference in seawater to fall within a range of not more than a prescribed value, while avoiding a size increase in the direction in which the plurality of panels are arranged. Note that the “a position away from the heat transfer tubes” means a position away from the heat transfer tubes to such a degree that heat exchange does not occur between the low-temperature liquefied gas flowing in each of the heat transfer tubes and the heating medium flowing in the bypass flow path.

In this case, the heating medium supply unit has a plurality of distribution headers which distribute the heating medium to the individual troughs, and a heating medium manifold which supplies the heating medium to each of the distribution headers. The bypass flow path may also have a shape extending from the heating medium manifold toward the receiver.

In this form, the part of the heating medium flows from the seawater manifold located upstream of each of the distribution headers toward the receiver. Accordingly, the diameter of each of the distribution headers located downstream of the heating medium manifold can be set to a value which allows, of the total amount of heating medium supplied to the heating medium manifold, the heating medium in an amount required for each of the troughs (required for heat exchange in each of the panels) to be supplied to each of the troughs. This suppresses an increase in the diameter of each of the distribution headers.

In this case, the bypass flow path preferably has a shape extending from a lower portion of the heating medium manifold toward the receiver.

This suppresses the deposition of mud or the like in the heating medium manifold and thus reduces the load of a maintenance operation for the heating medium manifold.

Alternatively, the heating medium supply unit has a plurality of distribution headers which distribute the heating medium to the individual troughs, and a heating medium manifold which supplies the heating medium to each of the distribution headers. The bypass flow path may also have a shape extending from a downstream end portion of each of the distribution headers toward the receiver.

In this form, the occurrence of heating medium stagnation in the downstream end portion of the distribution header is suppressed and therefore the load of the maintenance operation for the downstream end portion is reduced.

In this case, the bypass flow path preferably has a shape extending from a lower portion of a downstream end portion of each of the distribution headers toward the receiver.

This suppresses the deposition of mud or the like in the downstream end portion of the distribution header and thus further reduces the load of the maintenance operation for the downstream end portion.

This application is based on Japanese Patent application No. 2015-202720 filed in Japan Patent Office on October 14, 2015, the contents of which are hereby incorporated by reference.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.

Claims

A gas evaporator that heats a low temperature liquid gas using a heating medium to vaporize the low temperature liquid gas, the gas evaporator comprising: a plurality of panels each having a plurality of heat transfer tubes arranged along a specified direction, the plurality panels are arranged at intervals along a direction that intersects the specified direction; a plurality of troughs arranged at intervals along an arrangement direction in which the plurality of panels are arranged to supply the heating medium to the heat transfer tubes of each of the panels; a heating medium supply unit which supplies the heating medium to each of the troughs; a receiver that receives the heating medium under each of the panels; and a bypass flow path through which a portion of the heating medium is conducted from the heating medium supply unit to the receiver without passing through any of the troughs and any of the heat transfer tubes, each of the heat transfer tubes causing heat transfer between the low temperature liquid gas contained in the transfer tube and the heating medium flowing along an external surface of the heat transfer tube to heat the low temperature liquid gas, and the bypass flow path extends from the heating medium supply unit to the receiver at a position remote from the heat transfer tubes.

The gas evaporator according to claim 1, wherein the heating medium supply unit comprises: a plurality of distribution heads which distribute the heating medium over the individual troughs; and a heating medium manifold supplying the heating medium to each of the manifold heads, and the bypass flow path having a shape extending from the heating medium manifold to the receiver.

The gas evaporator of claim 2, wherein the bypass flow path has a shape extending from a lower portion of the heating medium manifold to the receiver.

The gas evaporator according to claim 1, wherein the heating medium supply unit comprises: a plurality of distribution heads which distribute the heating medium over the individual troughs; and a heating medium manifold supplying the heating medium to each of the manifolds, and the bypass flow path having a shape extending from a downstream end portion of each of the manifolds to the receiver.

The gas evaporator of claim 4, wherein the bypass flow path has a shape extending from a lower portion of a downstream end portion of each of the manifolds to the receiver.