JP2689071B2 - Liquefied natural gas vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vaporizer for vaporizing liquefied natural gas and adjusting it to a predetermined heat quantity,
The natural gas vaporized by the former vaporizer is mixed with the liquefied petroleum gas for heat quantity adjustment in the latter open rack heat exchanger, and the temperature is raised to generate natural gas at 0 ° C or higher. Liquefaction that realizes efficient temperature rising vaporization by reducing the load in the first stage without the need for it, and by arranging a sparge pipe in the inlet header tank at the latter stage and by uniformly mixing a predetermined amount of liquefied petroleum gas with natural gas. The present invention relates to a natural gas vaporizer.

[0002]

2. Description of the Related Art An open rack type vaporizer that is frequently used as a vaporizer for liquefied natural gas (hereinafter referred to as LNG) is:
For example, a fin tube in which a pair of fins project in the diameter direction is arranged in the fin direction to form a single panel, and a header tank is provided at the upper and lower ends thereof to form a heat exchange panel, and a plurality of the panels are simultaneously formed. This is a structure in which seawater as a heat medium flows down to the heat exchange panel surface from the watering trough disposed above the heat exchange panel.

[0003] When natural gas (hereinafter referred to as NG) heated and vaporized by an open rack type vaporizer or the like is used as city gas, for example, various types of L having different compositions of methane and the like are used.
Since it is necessary to supply a gas having a stable calorific value from the NG, the calorific value is generally adjusted by mixing the liquefied petroleum gas having a high calorific value (hereinafter referred to as LPG) with the LNG having a low calorific value.

[0004] The LNG vaporizer for city gas, which needs to adjust the calorific value of the generated gas, needs to have a structure in which LPG is mixed into LNG having a low calorific value.
When LPG (−45 ° C.) is directly mixed with G, there is a problem that LPG is cooled and methanol in LPG is separated and precipitated. Therefore, as shown in FIG. 6, in addition to the vaporizer 2 in which a large number of vaporization heat exchange panels 1 are arranged, the LPG is vaporized by a heat exchanger 3 using steam as a heat source, and NG from the vaporizer 2 is vaporized. There is used a vaporizer having a configuration in which vaporized petroleum gas is mixed.

Alternatively, in order to prevent precipitation of methanol, a part of LNG, for example, about 10% is taken out, vaporized at elevated temperature (0 ° C. or higher), and then mixed again with the original LNG, whereby the temperature of LNG is reduced. It becomes about −130 ° C., and methanol does not precipitate even if LPG is mixed. That is, as shown in FIG. 7, the conventional LNG vaporizer for city gas is different from the vaporizer 2 in which a large number of vaporization heat exchange panels 1 are arranged, and is used for raising a part of LNG to vaporize it by heating first. A vaporizer having a configuration in which a plurality of heat exchange panels 4 for warming are installed is used.

[0006]

As described above, the conventional LNG vaporizer for city gas shown in FIG. 6 has a problem that a heat exchanger for LPG vaporization and another dedicated heat source are required. Further, the conventional LNG vaporizer for city gas shown in FIG. 7 needs a heat exchange panel for temperature rise, that is, an independent LNG vaporizer, and the original heat exchange panel for vaporization vaporizes LNG and LPG. Since the ability to raise the temperature is required, for example, in a vaporizer that processes LNG at 100 tons / hour and LPG at 16.5 tons / hour, there are two heating heat exchange panels and vaporization heat exchange. There is a problem that the total number of heat exchange panels is increased to about 16 panels. Further, there is a problem that the total number of heat exchange panels becomes large, and the number of connecting pipes becomes large and the structure becomes complicated.

The present invention solves the problems such as the addition of heat exchange panels and the complication of piping in an LNG vaporizer for heat quantity adjustment for city gas, etc. The purpose is to provide a vaporizer that realizes vaporization.

[0008]

DISCLOSURE OF THE INVENTION As a result of various studies, the inventors have conducted various studies for the purpose of a vaporizer having a simple structure and capable of heating and vaporizing LNG mixed with LPG with high heat exchange efficiency. NG vaporized with a vaporizer such as
In addition, since the LPG for heat quantity adjustment is mixed and heated in the open rack heat exchanger in the latter stage, there is no need to generate natural gas at 0 ° C or higher in the former stage, and the load in the former stage can be reduced, Therefore, the inventors have found that efficient temperature rising vaporization can be realized by arranging a sparge pipe in the header tank and uniformly mixing a predetermined amount of liquefied petroleum gas with natural gas, and completed the present invention.

That is, the present invention comprises a constitution in which natural gas (NG) vaporized by the vaporizer in the former stage is mixed with liquefied petroleum gas (LPG) for heat quantity adjustment in the superheater in the latter stage to raise the temperature. The superheater consists of an open rack heat exchanger, and a sparge pipe was placed in the natural gas (NG) inlet header tank provided at the lower end of the heat exchange panel to enable the supply and mixing of liquefied petroleum gas (LPG). A characteristic liquefied natural gas (LNG) vaporizer. Further, according to the present invention, in the above configuration, the liquefied petroleum gas (LPG) supply hole diameter of the sparge pipe is smaller than the natural gas (NG) supply hole diameter of the header tank, and the liquefied petroleum gas (LPG) is used.
We propose a liquefied natural gas (LNG) vaporizer characterized by being determined by the ratio of the flow rate or flow rate and the total flow rate or flow rate of natural gas (NG) and liquefied petroleum gas (LPG).

Further, according to the present invention, as an example of the structure in which the sparge pipe is arranged in the natural gas (NG) inlet header tank, a sparge pipe having a supporting member having a modified cross section at the bottom is loosely inserted and arranged in the inlet header tank. The upper and lower parts are divided into two parts, and natural gas from the lower passage is allowed to flow into the heat exchange panel after passing between the inner peripheral surface of the header tank and the supporting member and near the liquefied petroleum gas supply hole of the sparge pipe. It consists of an inlet header tank with an 8-shaped passage whose cross section communicates with the top and bottom. A sparge pipe is loosely inserted in the upper passage. Natural gas from the lower passage is liquefied petroleum between the inner surface of the header tank and the sparge pipe and the sparge pipe. It has a structure that allows it to flow into the heat exchange panel through the vicinity of the gas supply hole, and has an internal cross section that divides the passage into two parts, left and right. And the partition wall upper consists inlet header tank to form a Supajipaipu, natural gas from the left and right channel is proposed to fit a configuration that enables flow into the heat exchange panel and passes through the liquefied petroleum gas supply holes near the Supajipaipu.

In the present invention, as the former vaporizer for vaporizing LNG, any heating source such as an open rack vaporizer having various conventional structures can be used as long as it can vaporize LNG. Also available in heat exchangers. Further, the superheater in the latter stage may be configured by using any heating source as long as it is an open rack type heat exchanger, and the LP in the NG inlet header tank of the heat exchanger may be used.
As means for supplying and mixing G, sparge pipes of various configurations shown in the embodiments can be adopted.

[0012]

The LNG according to the present invention will be described below with reference to the drawings.
The operation of the vaporizer will be described. FIG. 1 is a perspective explanatory view showing the configuration of a vaporizer provided with a heat quantity adjusting mechanism according to the present invention, and FIGS. 2 to 5 are explanatory views showing the details of a sparge pipe in an NG inlet header tank, where A is a vertical section. Explanatory drawing, B is a perspective explanatory view. Here, an example will be described in which an open rack type vaporizer excellent in heat exchange between LNG and seawater is used for the vaporizers of the first and second stages. The open rack type vaporizers 10 and 20 in the front and rear stages are, for example, fin tubes in which a pair of fins are projected in the diametrical direction are arranged in the fin direction to form a single panel, and header tanks are provided at the upper and lower ends thereof. 12, 13, 22, and 23 are provided to form heat exchange panels 11 and 21, and a plurality of panels 11 and 21 are arranged in a row, and a sprinkling trough (not shown) arranged above the heat exchange panels 11 and 21. ) Is a structure in which seawater, which is a heat medium, flows down to the surfaces of the heat exchange panels 11 and 21.

The open rack type vaporizer 20 in the latter stage is
A low temperature NG inlet header tank 22 is provided at the lower end of the LPG mixing heat exchange panel 21, and a sparge pipe 30 is disposed inside the low temperature NG inlet header tank 22. Here, both ends of the header tank 22 are arranged. It is configured to hold the sparge pipe 30 at a required height position in the tank by using a jig (not shown). As shown in FIG. 2, the low temperature NG inlet header tank 22 is provided with a large number of NG supply holes 25 for supplying NG into each fin tube forming the heat exchange panel 21, and the sparge pipe 30 is also supplied with NG. LP with a small diameter so as to look through hole 25
The G supply hole 31 is provided, and the LPG ejected from the LPG supply hole 31 is lifted by the NG wrapping around from the periphery of the sparge pipe 30 and introduced into each fin tube, that is, the heat exchange panel 21, and the low temperature NG is generated. While the temperature is raised to 0 ° C or higher by heat exchange with seawater, L
PG is also heated and vaporized at the same time, and as a result, NG with the calorific value adjusted is obtained.

In the present invention, the diameter of the LPG supply hole 31 of the sparge pipe 30 is smaller than the diameter of the NG supply hole 25 of the NG inlet header tank 22, and the LPG flow rate or flow rate and the total flow rate or total flow rate of the NG and LPG are calculated. By determining the predetermined pore size based on the ratio, it is possible to improve mixing efficiency and achieve uniform mixing.

The sparge pipe 30 shown in FIG. 3 has a support member 3 having a modified cross section formed of a plate material, a block material or the like at the lower portion thereof.
2 is arranged and fixed at regular intervals, for example, and is inserted into the low temperature NG inlet header tank 22 so as to be supported by the supporting member 32, and the LPG ejected from the LPG supply hole 31.
Since the amount of lift of the NG depends on the flow rate of NG flowing from the periphery of the sparge pipe 30, it is necessary to make the flow rate of NG uniform around each LPG supply hole 31. A cutout portion is provided so as not to prevent passage of the low temperature NG from the low temperature NG passage 24 formed in the above. Therefore, the LPG introduced into the heat exchange panel 21 by the low-temperature NG is heated and vaporized while the low-temperature NG is heated to 0 ° C. or higher by the heat exchange with the seawater, and as a result, the calorie-regulated NG is adjusted. Is obtained.

Low temperature NG inlet header tank 4 shown in FIG.
Reference numeral 0 denotes a mold material, a passage having an 8-shaped cross section is formed therein, and the sparge pipe 30 is loosely inserted and arranged in the upper passage 41. Of the LPG supply hole 3 when it rises up and passes through the NG supply hole 43 and flows into each fin tube.
The LPG ejected from No. 1 can be lifted and mixed, and the LPG introduced into the heat exchange panel 21 is low temperature NG.
Is heated and vaporized while it is heated to 0 ° C. or higher by heat exchange with seawater, and as a result, heat-adjusted NG is obtained.

Low temperature NG inlet header tank 5 shown in FIG.
Reference numeral 0 denotes a mold material which is provided with a partition wall 51 that divides the tank into two parts and an upper part thereof is provided with a sparge pipe section 52. From the low temperature NG passages 54 and 55 formed on both sides of the partition wall 51, When the low-temperature NG passes through the NG supply hole 56 and flows into each fin tube, the LPG ejected from the LPG supply hole 53 provided in the sparge pipe portion 52 can be lifted and mixed, and introduced into the heat exchange panel 21. The low temperature NG is heated and vaporized while the low temperature NG is heated to 0 ° C. or higher due to heat exchange with seawater, and as a result, heat-regulated NG is obtained.

Regardless of which of the above-mentioned sparge pipes is adopted, LNG is vaporized by the vaporizer 10 in the former stage and mixed with LPG in the vaporizer 20 in the latter stage, so that the vaporizer 10 in the former stage raises NG to 0 ° C. or higher. The ability to raise the temperature is not necessary, and the number of heat exchange panels 11 can be reduced. In addition, the applicant has adopted a double-tube structure for the heat exchange pipe, for example, supplying liquefied natural gas from the upper end to the inner pipe and inverting it from the lower end, and passing the passage between the outer pipe and the inner pipe to the upper part of the outer pipe. U
A double-tube open rack type vaporizer was proposed (Japanese Patent Laid-Open No. 3-286990), which has a structure in which vaporized gas is derived by a mold flow, prevents flow rate hunting, and reduces ice formation. By adopting the tubular vaporizer as the former vaporizer, it is not necessary to raise the temperature to 0 ° C. or higher as described above, so that the problem of ice accretion can be solved.

[0019]

Example: LNG is 100 tons / hour, LPG is 16.
When vaporizing at a temperature of 5 tons / hour to obtain NG at 0 ° C., in the above-described conventional configuration of FIG.
Although the number of heat exchange panels for vaporization is 16 and the total number of heat exchange panels is large, the number of heat exchange panels for vaporization in the preceding stage can be reduced to 12 in the vaporizer according to the present invention of FIG. 1 described above. It was

[0020]

The liquefied natural gas vaporizer according to the present invention heats up the natural gas vaporized by the former vaporizer by mixing the liquefied petroleum gas for heat quantity adjustment in the latter open rack heat exchanger. With this configuration, there is no need to generate natural gas at 0 ° C or higher in the first stage, and the load in the first stage can be reduced, so that, for example, the number of heat exchange panels can be reduced, and the double tube open that can solve the problem of icing A rack-type vaporizer can be used, and a sparge pipe is placed in the header tank at a later stage to uniformly mix a predetermined amount of liquefied petroleum gas with natural gas, thereby achieving efficient temperature rising vaporization and a predetermined heat amount. A regulated natural gas can be stably supplied.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing a configuration of a vaporizer provided with a heat quantity adjusting mechanism according to the present invention. 2 to 5 are explanatory diagrams showing details of the sparge pipe in the NG inlet header tank, where A is a longitudinal sectional explanatory diagram and B is a perspective explanatory diagram, respectively.

2A and 2B are explanatory diagrams showing details of a sparge pipe in a low temperature NG inlet header tank, where A is a longitudinal sectional explanatory diagram and B is a perspective explanatory diagram.

3A and 3B are explanatory diagrams showing details of a sparge pipe having a support material in a low temperature NG inlet header tank, where A is a longitudinal sectional explanatory diagram and B is a perspective explanatory diagram.

FIG. 4 is an explanatory diagram showing details of a sparge pipe in a low temperature NG inlet header tank made of a mold material, A is a longitudinal sectional explanatory diagram, and B is a perspective explanatory diagram.

5A and 5B are explanatory views showing details of a sparge pipe integrally formed in a low temperature NG inlet header tank made of a mold material, where A is a longitudinal sectional view and B is a perspective explanatory view.

FIG. 6 is a perspective explanatory view showing a configuration example of a conventional open rack type vaporizer for vaporizing liquefied natural gas.

FIG. 7 is a perspective explanatory view showing a configuration example of another conventional open rack type vaporizer for vaporizing liquefied natural gas.

[Explanation of symbols]

 1 heat exchange panel for vaporization 2 vaporizer 3 heat exchanger 4 heat exchange panel for temperature rise 10, 20 open rack type vaporizer 11,21 heat exchange panel 12, 13 header tank 22, 40, 50 low temperature NG inlet header tank 25 , 43, 56 NG supply hole 24, 42, 54, 55 Low temperature NG passage 30 Sparge pipe 31, 53 LPG supply hole 41 Upper passage 51 Partition wall 52 Sparge pipe section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyasu Miura 38-37-402, Shirahatagami-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Innovator, Hitoshi Shoya 1-10 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Precision Industries Co., Ltd. (72) Inventor Kazuya Sahara 1-10 Fuso-cho, Amagasaki City, Hyogo Sumitomo Precision Industries Co., Ltd. (56) Reference JP-A-6-346073 (JP, A)

Claims (5)

(57) [Claims] 1. A structure comprising a natural gas vaporized by a vaporizer in a first stage and a liquefied petroleum gas for heat quantity adjustment mixed in a latter superheater to raise the temperature, wherein the superheater is an open rack heat exchanger. A liquefied natural gas vaporizer comprising a sparge pipe arranged in a natural gas inlet header tank provided at the lower end of the heat exchange panel to enable supply and mixing of liquefied petroleum gas. 2. The liquefied petroleum gas supply hole diameter of the sparge pipe is smaller than the natural gas supply hole diameter of the inlet header tank,
The liquefied natural gas vaporizer according to claim 1, which is determined by a ratio of the liquefied petroleum gas flow rate and the total flow rate of natural gas and liquefied petroleum gas. 3. A sparge pipe provided with a supporting member having a modified cross section at its lower portion is loosely inserted in the inlet header tank to divide the inside into two parts, and the natural gas from the lower passage supports the inner peripheral surface of the header tank and the supporting member. 3. The liquefied natural gas vaporizer according to claim 1 or 2, wherein the liquefied natural gas vaporizer can be introduced into the heat exchange panel by passing between the material and the vicinity of the liquefied petroleum gas supply hole of the sparge pipe. 4. An inlet header tank having an 8-shaped passage whose inner cross section communicates with the upper and lower sides. A sparge pipe is loosely inserted in the upper passage, and natural gas from the lower passage is connected to the inner surface of the header tank and the sparge pipe. The liquefied natural gas vaporizer according to claim 1 or 2, wherein the liquefied natural gas vaporizer can flow into the heat exchange panel after passing through the space and the vicinity of the liquefied petroleum gas supply hole of the sparge pipe. 5. A liquefied petroleum gas supply hole for a natural gas from the left and right passages, wherein the inner cross section has a partition wall that divides the passage into two parts, the upper part of the partition wall is an inlet header tank in which a sparge pipe is formed. The liquefied natural gas vaporizer according to claim 1 or 2, wherein the liquefied natural gas vaporizer can pass through the vicinity and flow into the heat exchange panel.