LNG receiving structure

Abstract

An LNG receiving structure (101) is provided with: a leader pipe (1) that is located below a receiving pipe (102) that penetrates a roof of an LNG tank, and extends as far as a bottom portion of the LNG tank; a hopper (2) that is provided at a top end of the leader pipe, and receives LNG expelled from the receiving pipe; a regulating component (3) that is provided inside the hopper, and regulates the flow of the LNG expelled from the receiving pipe such that this LNG flows down along an inside wall of the leader pipe; and a gas discharge port (4) that is provided in the hopper, and discharges to an outside of the hopper gas that has risen upwards from the leader pipe. By providing this LNG receiving structure, when a plurality of types of LNG that each have a different density are stored in the same LNG tank, it is possible to keep to a minimum any risk that rollover might occur.

Claims

1. An LNG receiving structure comprising: a receiving pipe that penetrates a roof of an LNG tank; a leader pipe that is located below the receiving pipe and extends as far as a bottom portion of the LNG tank; a hopper that is provided at a top end of the leader pipe, and is positioned and configured to receive LNG expelled from the receiving pipe; a regulating component that is provided inside the hopper, and is positioned and configured to regulate the flow of the LNG expelled from the receiving pipe such that the LNG flows down along an inside wall of the leader pipe; a gas discharge port that is provided in the hopper, and is positioned and configured to discharge to an outside of the hopper gas that has risen upwards from the leader pipe, and a partitioning component that is positioned and configured to partition an internal space inside the leader pipe into an LNG flow path and a gas flow path, wherein the partitioning component is a tubular component that forms a space between an outside wall of the partitioning component and the inside wall of the leader pipe as the LNG flow path, and forms an internal space of the partitioning component as the gas flow path, and wherein a top end of the partitioning component opens so as to face a bottom end of the regulating component, and a top end surface of the partitioning component constitutes a horizontal plane at a position that coincides with the top end of the leader pipe.

2. The LNG receiving structure according to claim 1, wherein the regulating component is a V-plate formed in a V-shape, and the V-plate is positioned such that an apex portion of the V-plate faces an expulsion portion of the receiving pipe, and such that a space on an inner side of the V-plate communicates with the gas discharge port.

3. The LNG receiving structure according to claim 2, wherein an apex angle of the V-plate is set to an angle that enables respective line extensions of a pair of inclined portions of the V-plate to come into contact with the leader pipe.

4. The LNG receiving structure according to claim 3, wherein the apex angle of the V-plate is set to an angle that causes the top end of the leader pipe to be positioned on the respective line extensions of the pair of inclined portions of the V-plate.

5. The LNG receiving structure according to claim 1, further comprising an exhaust pipe that communicates with the gas discharge port, and extends upwards.

6. The LNG receiving structure according to claim 1, wherein the regulating component is a V-plate formed in a V-shape, and the V-plate is positioned such that an apex portion of the V-plate faces an expulsion portion of the receiving pipe, and such that a space on an inner side of the V-plate communicates with the gas discharge port, and wherein an apex angle of the V-plate is set to an angle that causes the top end of the leader pipe to be positioned on respective line extensions of a pair of inclined portions of the V-plate.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1A is a perspective view showing an LNG receiving structure according to an embodiment.

(2) FIG. 1B is a cross-sectional view taken along a line A-A in FIG. 1A of the LNG receiving structure according to the embodiment.

(3) FIG. 2 is a view illustrating the operation and effects of the LNG receiving structure according to the embodiment.

(4) FIG. 3 is a variant example of an LNG receiving structure according to the present invention.

DESCRIPTION OF EMBODIMENTS

(5) Hereinafter, an embodiment of the present invention will be described with reference made to the drawings.

(6) FIG. 1A is a perspective view of an LNG receiving structure 101 of the present embodiment. FIG. 1B is a cross-sectional view taken along a line A-A of the LNG receiving structure 101.

(7) In these drawings, the symbol 1 is a leader pipe that is located below a receiving pipe 102 that penetrates the roof of the LNG tank and extends as far as the bottom portion of the LNG tank. The symbol 2 is a hopper that is provided at a top end of the leader pipe 1 and receives LNG expelled from the receiving pipe 102. The symbol 3 is a regulating component that is provided inside the hopper 2 and regulates the flow of the LNG expelled from the receiving pipe 102 such that this LNG flows down along an inside wall of the leader pipe 1. The symbol 4 is a gas discharge port that is provided in the hopper 2 and discharges gas that has risen upwards from the leader pipe 1 to the outside of the hopper 2. The symbol 5 is a partitioning component that is provided inside the leader pipe 1 and partitions the internal space of the leader pipe 1 into an LNG flow path FL and a gas flow path FG.

(8) The regulating component 3 is a V-plate that is formed in a V-shape. This V-plate 3 is positioned such that an apex portion 3a of the V-plate 3 faces an expulsion portion 102a of the receiving pipe 102, and such that a space 3b on the inner side of the V-plate 3 (i.e., a space sandwiched by a pair of inclined portions 3c and 3d) communicates with the gas discharge port 4. Moreover, an apex angle of the V-plate 3 is set to an angle that causes the top end of the leader pipe 1 to be positioned on line extensions L1 and L2 of the pair of inclined portions 3c and 3d of the V-plate 3.

(9) The partitioning component 5 is a tubular component that forms a space between its own outside wall and the inside wall of the leader pipe 1 as the LNG flow path FL, and forms its own internal space as the gas flow path FG. Note that in FIG. 1, a state is shown in which a single partitioning component 5 is provided in a portion where the leader pipe 1 joins to the hopper 2, however, it is also possible for a plurality of partitioning components 5 to be placed at uniform intervals along the lengthwise direction of the leader pipe 1.

(10) Next, the operation and effects of the LNG receiving structure 101 that is constructed in the manner described above will be described.

(11) Light LNG that has been unloaded from an LNG tanker is transferred to the LNG tank through the receiving pipe 102. This light LNG is gas-liquid fluid mixture that contains flash gas (hereinafter, referred to simply as gas). As is shown in FIG. 2, the light LNG discharged into the hopper 2 from the expulsion portion 102a of the receiving pipe 102 is split into light LNG that flows along the one inclined portion 3c of the V-plate 3, and light LNG that flows along the other inclined portion 3d of the V-plate 3.

(12) After both flows of the light LNG that have been split by the V-plate 3 have flowed down and collided with the bottom end portion of the hopper 2, they flow down along the inside wall of the leader pipe 1. At this time, by causing the light LNG to flow along the LNG flow path FL that has been partitioned by the partitioning component 5, a flow regulating action towards the LNG is achieved. As a result, the light LNG flows down in a long distance towards the bottom portion of the LNG tank along the inside wall of the leader pipe 1 without being turbulent.

(13) In the process in which the light LNG flows downwards along the inside wall of the leader pipe 1 in this manner, the flow rate of the light LNG decelerates so that a gas-liquid separation is encouraged, and the gas separates from the light LNG. The separated gas rises inside the leader pipe 1 and arrives at the space 3b on the inside of the V-plate 3 via the gas flow path FG in the partitioning component 5. The gas that has risen as far as the space 3b on the inside of the V-plate 3 is then discharged to the outside of the hopper 2 from the gas discharge port 4 that communicates with the space 3b.

(14) As is described above, when a gas-liquid separation is encouraged through the process of the light LNG flowing down the inside wall of the leader pipe 1, the further the distance of this downward flow, the greater the density of the light LNG becomes. Namely, if the light LNG is introduced through the leader pipe 1 when the heavy LNG has already accumulated inside the LNG tank, then the difference between the densities of the two types of LNG can be reduced. Consequently, the light LNG is able to be expelled more easily from the bottom end of the leader pipe 1, and it becomes more difficult for the light LNG to overflow from the hopper 2. Accordingly, according to the present embodiment, it becomes difficult for stratification, which causes rollover to occur, to be generated, and it is possible to keep to a minimum any risk that rollover might occur.

(15) Note that the present invention is not limited to the above-described embodiment, and the following variant examples of the present invention may be also be proffered.

(16) (1) In the above-described embodiment, a case is illustrated in which the V-plate 3, which is formed in a V-shape, is used as a regulating component, however, the shape of the regulating component is not particularly restricted provided that it is able to regulate the flow of the LNG such that the LNG expelled from the receiving tube 2 flows downwards along the inside wall of the leader pipe 1.
(2) In the above-described embodiment, the apex angle of the V-plate 3 is set to an angle that causes the top end of the leader pipe 1 to be positioned on the line extensions L1 and L2 of the pair of inclined portions 3c and 3d of the V-plate 3. However, it is sufficient for the apex angle of the V-plate 3 to be set to an angle that enables the aforementioned line extensions L1 and L2 to come into contact with the leader pipe 1. Here, this contact between the line extensions L1 and L2 and the leader pipe 1 includes not only cases in which the top end of the leader pipe 1 is positioned on the line extensions L1 and L2, but also cases in which the line extensions L1 and L2 intersect with the leader pipe 1.
(3) In the above-described embodiment, a case is illustrated in which the partitioning component 5 that partitions the internal space inside the leader pipe 1 into the LNG flow path FL and the gas flow path FG is provided inside the leader pipe 1, however, it is not absolutely essential for this partitioning component 5 to be provided.
(4) In the structure shown in FIG. 1, when the liquid surface inside the LNG tank reaches as far as the gas discharge port 4, there is a possibility that liquid will intrude into the inside of the hopper 2 from the gas discharge port 4, and will obstruct the discharging of the gas and the introduction of the light LNG. In order to prevent this, as is shown in FIG. 3, it is also possible to employ a structure in which an exhaust pipe 6 that communicates with the gas discharge port 4 and extends upwards is connected to the hopper 2.

INDUSTRIAL APPLICABILITY

(17) According to the present invention, when a plurality of types of LNG that each have a different density are stored in the same LNG tank, it is possible to keep to a minimum any risk that rollover might occur.

REFERENCE SIGNS LIST

(18) 1: Leader pipe 2: Hopper 3: V-Plate (Regulating component) 4: Gas discharge port 5: Partitioning component 6: Exhaust pipe 101: LNG receiving structure 102: Receiving pipe