JPH06221783A - Liquified natural gas gasification device - Google Patents

Abstract

PURPOSE:To enable such problems as extension of a heat exchanging panel or complication of pipes and the like to be eliminated by a method wherein a superheater is of a plate fin type heat exchanger, and liquified petroleum gas can be supplied and mixed in a predetermined natural gas passage between the plates. CONSTITUTION:A superheater 20 is of a plate fin type heat exchanger in which fins 22 are held betwen plates 21 and 21 and a desired number of low temperature natural gas passages 24 closed with spacer bars 23 are piled up. A liquified petroleum gas header tank 26 is installed at an upper part of the exchanger, and injection tubes 27 with many punched holes are inserted into the temperature natural gas passages 24 and arranged there. Then, the tubes communicate with the liquified petroleum gas tank 26 so as to enable liquified petroleum gas to be fed into the passage 24. With such an arrangement as above, it is not necessary to generate natural gas of temperature of 0 deg.C or higher at a front stage and a load at the front stage can be reduced, resulting in that it is possible to reduce the number of heat exchanging panels.

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 liquefied petroleum gas for heat quantity adjustment by the plate fin type heat exchanger in the latter stage, and the temperature is raised to generate natural gas at 0 ° C or higher. The present invention relates to a liquefied natural gas vaporizer that realizes efficient temperature-rising vaporization by using a plate fin heat exchanger that can reduce the load in the preceding stage and is efficient in increasing the temperature of gas in the latter stage without the need.

[0002]

2. Description of the Related Art An open rack type vaporizer, which is often used as a vaporizer for liquefied natural gas (hereinafter referred to as LNG),
For example, fin tubes with a pair of fins protruding 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 of the fin tubes to form a heat exchange panel. The structure is such that seawater, which is a heat medium, flows down to the surface of the heat exchange panel from the sprinkling trough arranged above the heat exchange panel.

Natural gas (hereinafter referred to as NG) which has been vaporized at elevated temperatures by an open rack type vaporizer or the like, for example, when used as city gas, has various types of L having different compositions such as methane.
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.

The LNG vaporizer for city gas, which requires adjustment of the calorific value of the generated gas, needs to have a structure in which LPG is mixed with LNG having a low calorific value, but LN at an extremely low temperature (-160 ° C.).
When LPG (−45 ° C.) is directly mixed with G, there is a problem that LPG is cooled and methanol in LPG is separated and deposited.

Therefore, 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, so that 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. 3, the conventional LNG vaporizer for city gas is different from the vaporizer 2 in which a large number of the vaporizing heat exchange panels 1 are arranged, and is used for raising a portion of LNG to evaporate the temperature first. It has a configuration in which a plurality of heat exchange panels 3 for warming are installed.

[0006]

As described above, the conventional LNG vaporizer for city gas needs a heat exchange panel for raising the temperature, that is, an independent LNG vaporizer, and is used as the original heat exchange panel for vaporization. Is required to vaporize and raise the temperature of LNG and LPG. Therefore, for example, in a vaporizer that processes LNG at 100 tons / hour and LPG at 16.5 tons / hour, a heat exchange panel for raising temperature is used. There is a problem that the total number of heat exchange panels is large, with two and about 16 heat exchange panels for vaporization. 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 adjusting the amount of heat for city gas, etc., and has a simple structure and high temperature vaporization with high heat exchange efficiency. The purpose of the present invention is to provide a liquefied natural gas vaporizer that realizes the above.

[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 plate fin type 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 an efficient plate-fin heat exchanger can be used to raise the temperature of the gas, and efficient vaporization of elevated temperature can be realized, and the present invention has been completed.

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. A liquefied natural gas (LNG) vaporizer characterized in that the superheater is a plate fin type heat exchanger, and liquefied petroleum gas (LPG) can be supplied and mixed into a predetermined natural gas (NG) passage between the plates. Is.

Further, according to the present invention, in the above structure,
Liquefied natural gas, characterized in that a large number of perforated injection tubes are inserted through a predetermined natural gas (NG) passage between the plates to allow liquefied petroleum gas (LPG) to be supplied and mixed into the natural gas (NG) passage. It is a gas (LNG) vaporizer.

In the present invention, as the vaporizer at the former stage for vaporizing LNG, any heating source such as an open rack type vaporizer having various conventional constitutions can be used as long as it can vaporize LNG. Also available in heat exchangers.

In the present invention, the superheater in the latter stage may have a structure using any heating source as long as it is a plate fin type heat exchanger, and also means for supplying and mixing LPG into the NG passage of the heat exchanger. In addition to the injection tube of the embodiment, any known configuration such as a distribution fin configuration can be adopted.

[0013]

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 structure of a vaporizer provided with a heat quantity adjusting mechanism according to the present invention, and FIG. 2 is a transverse explanatory view showing details of a superheater. Here, an open rack type vaporizer excellent in heat exchange between LNG and seawater is used for the former vaporizer, and a plate fin type heat exchanger excellent in heat exchange performance is used for the latter superheater.

The open rack type vaporizer 10 is, for example, a fin tube having a pair of fins protruding in the diametrical direction arranged in the fin direction to form a single panel, and header tanks 12, 13 at the upper and lower ends thereof. Is provided to form the heat exchange panel 11, and a plurality of the panels 11 are arranged in parallel,
This is a structure in which seawater as a heat medium is caused to flow down to the surface of the heat exchange panel 11 from a sprinkling trough (not shown) arranged above the heat exchange panel.

The superheater 20 comprises a plate fin type heat exchanger in which a required number of low temperature NG passages 24, which are fins 22 sandwiched between the plates 21 and 21 and are closed by a spacer bar 23 to form fluid passages, are stacked. A structure in which an LPG header tank 26 is attached to the upper part, a large number of injection tubes 27 perforated are placed in the low temperature NG passage 24, and this is communicated with the LPG header tank 26 so that LPG can be introduced into the passage 24. The water sprinkling trough (not shown) disposed above the superheater 20 causes the seawater of the heat medium to flow down to both outer surfaces of the superheater.

In the above-mentioned structure, first, the cryogenic temperature (-160 ° C.) LNG supplied to the open rack type vaporizer 10 is vaporized by heat exchange with seawater and becomes a low temperature NG of 0 ° C. or less. Next, the low temperature NG is introduced into the superheater 20, and a predetermined amount of heat quantity adjusting LPG is introduced in the low temperature NG passage 24.
Is mixed with and heated by heat exchange with seawater to obtain NG having a calorific value adjusted to 0 ° C. or higher.

LNG evaporates by the vaporizer 10, but since it is mixed with LPG in the latter stage, the vaporizer 10 does not need the ability to raise the temperature to 0 ° C. or higher. For example, 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. We proposed a double-tube open rack type vaporizer (U.S. Pat. No. 3,286,990) in which the vaporized gas is derived by a U-shaped flow, flow rate hunting is prevented, and icing is reduced. By adopting the heavy-tube type vaporizer as the former vaporizer, it is not necessary to raise the temperature to 0 ° C. or higher, so that the problem of ice accretion can be solved.

[0018]

Example: LNG 100 tons / hour, LPG 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

[0019]

According to the present invention, the NG vaporized by the vaporizer of the preceding stage is mixed with the LPG for heat quantity adjustment in the plate fin type heat exchanger of the latter stage to raise the temperature, so that the temperature is 0 ° C. or higher in the former stage. Since it is not necessary to generate natural gas and the load in the preceding stage can be reduced, for example, the number of heat exchange panels can be reduced, and a double pipe open rack type vaporizer capable of solving the problem of icing can be used. In addition, since a plate fin heat exchanger with high efficiency can be used in the latter stage to raise the temperature of NG, there is an advantage that the total amount of seawater used, that is, the amount of heat medium can be reduced.

[Brief description of 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.

FIG. 2 is a cross-sectional explanatory view showing details of a superheater in FIG.

FIG. 3 is a perspective explanatory view showing a configuration of a vaporizer provided with a conventional heat quantity adjusting mechanism.

[Explanation of symbols]

 1 heat exchange panel for vaporization 2 vaporizer 3 heat exchange panel for temperature rise 10 open rack type vaporizer 11 heat exchange panel 12, 13 header tank 20 superheater 21 plate 22 fin 23 space server 24 low temperature NG passage 26 LPG header tank 27 Injection tube

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takahide Yamamoto 1-48-6-1402 Higashiikebukuro, Toshima-ku, Tokyo (72) Inventor Toshiyasu Miura 41-402 Shirahatakami-cho, Kanagawa-ku, Yokohama (72) Inventor Shoya Ninobu 1-10 Fuso-cho, Amagasaki-shi, Hyogo Prefecture Sumitomo Precision Industries Ltd. (72) Inventor Yu Akiyama 1-10 Fuso-cho, Amagasaki-shi Hyogo Sumitomo Precision Industries Ltd. (72) Inventor Yoshiro Sotoike Sumitomo Precision Industries, Ltd. 1-10 Fuso-cho, Amagasaki-shi, Hyogo

Claims (2)

[Claims] 1. A structure comprising a natural gas vaporized by a vaporizer in the first stage and a liquefied petroleum gas for heat quantity adjustment mixed in a latter superheater to raise the temperature, wherein the superheater is a plate fin type heat exchanger. And a liquefied petroleum gas vaporizer capable of supplying and mixing liquefied petroleum gas into a predetermined natural gas passage between the plates. 2. The liquefaction according to claim 1, wherein a large number of injection tubes having a plurality of holes are inserted and arranged in a predetermined natural gas passage between the plates so that liquefied petroleum gas can be supplied and mixed into the natural gas passage. Natural gas vaporizer.