JPS59166799A - Evaporator for liquefied natural gas - Google Patents

Abstract

PURPOSE:To efficiently evaporate the liquefied natural gas by using the intermediate thermal medium when a shell and tube type heat exchanger is used as an evaporator for liquefied natural gas. CONSTITUTION:One side between the shell side or the tube T side of a heat exchanger 1 is filled with the intermediate thermal medium 4, and said medium is allowed to circulate in a circulation system R through an introducing part 5 and a leading-out part 6, and the heating medium 7 such as sea water is allowed to circulate in the other side through an introducing part 8 and a leading-out part 9. Further, when liquefied natural gas is introduced from the introducing part 2, the liquefied natural gas is heated with the intermediate thermal medium 4 by the heating medium 7 and introduced into a heater 13 from the introducing part 3 through a demister 12, and then gasfified, to form gaseous natural gas. Said intermediate medium 4 returns into the circulation system R from the leading-out part 6 and circulates.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquefied natural gas (LNG) vaporization device.

Since a liquefied natural gas vaporization device is a heat exchanger between a heating medium such as seawater or river water and the liquefied natural gas, its efficiency and economical efficiency greatly depend on the heat exchanger. Therefore, the heat exchanger is already in the stage of completion, and the most efficient or good one is on the horizon.
It would be optimal if a shell-and-tube heat exchanger, which is economical and highly versatile, is applied to the vaporizer. However, this method of simply heating liquefied natural gas with a heat exchanger does not allow freezing due to the low temperature (-'+60℃) of liquefied natural gas, even if humid water or steam is used as the heating medium. Even if the heating medium is frozen, there is no risk of blockage, only the heat transfer property is reduced, but there is a disadvantage that the heat transfer area must be increased, and there is also a disadvantage that it is difficult to use.

The present invention utilizes a shell-and-tube heat exchanger in an extremely rational manner to create a vaporization device that can vaporize a large amount of liquefied natural gas more efficiently and economically with a relatively small heat transfer area. It is something that is offered as a donation. Example 1 will be described in detail below.

Code 1 is a shell and tube heat exchanger, s,
T is the shell IQ1. of the heat exchanger 1, respectively. ! , shows the tube side. Therefore, at the lower part of one side of the shell side S or tube side T, a liquefied natural gas introduction part 2,
If a vaporized natural gas outlet 3 is provided in the upper part, the blade side of the furnace may be provided;
An introduction section 5 and an outlet section 6 for the intermediate heat medium 4 are provided, which are connected to a circulation system R for the intermediate heat medium 4, which is composed of a single hydrocarbon such as octane, an isomer of these hydrocarbons, or a mixture of these hydrocarbons. . On the other side of the shell side S or the tube side T, an inlet 8 and an outlet 9 for a heating medium 7 such as seawater or river water are provided. Figure 1 is MiI-
This shows an example in which the blade side is the tube side T, and FIG. 2 shows an example in which the negative blade side is the shell side S. In the diagram showing a specific example, reference numeral 10 is an intermediate H1 medium circulation pump, 11 is a receiver for an intermediate heat exchanger, 12 is a demister, and 13 is a heater for vaporized natural gas. Also, a and b are a natural circulation path and a forced circulation path for the intermediate heat medium, respectively, and C is a pressure equalization pipe.

In this configuration, one side of the shell S or tube side T of the heat exchanger 1 is filled with an intermediate heat medium 4,
This is circulated by the circulation system R via the introduction part 5 and the outlet part 6, and the heating medium 7 such as seawater or river water is distributed to the other side 1111 through the introduction part 8 and the outlet part 9. let However, in such a state, when liquefied natural gas is introduced from the introduction part 2 provided at the lower part of the blade side, the liquefied natural gas is heated by the heating medium 7 together with the intermediate heat medium 4, that is, by the heating medium 7. It is heated by the heated intermediate heat medium 4, vaporizes and rises, enters the heater 13 from the outlet part 3 via the demister 12, and is completely vaporized to become vaporized natural gas. Further, the intermediate heat interrupter 4 returns to the circulation system R from the outlet portion 6 and is again circulated.

Since the present invention performs heat exchange between the liquefied natural gas and the heating body γ via the intermediate heat medium 4,
A feature of this heat exchanger 1 is that it is possible to perform extremely highly efficient heat exchange without sacrificing the efficiency of the heat exchanger 1.

Furthermore, as described above, the present invention is not intended to simultaneously exchange heat between the heating medium 7, the liquefied natural gas, and the intermediate heat medium 4, but rather to exchange heat between the heating medium 7 and the liquefied natural gas as they are. not,
Since it exchanges heat with the mixture of the intermediate heat medium 4 and liquefied natural gas, it effectively prevents the heating body 7 from freezing, thereby effectively blocking the flow path of the heating medium 7. There are some features that can be prevented. For this reason, the vaporizer of the present invention is characterized in that room temperature water, such as seawater or river water, can be used as is as the heating medium 7, and running costs can therefore be reduced. Historically, the present invention uses a hydrocarbon mixture such as propane, butane, etc. as the intermediate heat medium 4, and adjusts the heat amount of the vaporized natural gas in the outlet section 3 to an arbitrary value by appropriately adjusting the ratio of these. In other words, when producing city gas from liquefied natural gas, it is possible to simultaneously adjust the amount of heat.

As an example of implementing the present invention, in the configuration shown in FIG.
The #l composition of liquefied natural gas shown in the table below was heated to -160°C.
1 pressure 45 k / z + 20 t i Q T / H1 Also, initially n-butane was used as an intermediate heating medium at 1.7 T/H1, and when the heating medium was 400 T/H of irrigation water at a temperature of 18°C and the temperature was 2° 1240014 m3/) of vaporized natural gas with the composition shown in the table below. The seawater temperature in
There was.

The heat transfer area of the heat exchanger used above is approximately 60 m2, which is the heat transfer surface of 4.71H or approximately 70 m2 required for an oven rack type heat exchanger with the same vaporization capacity. It can be seen that the present invention allows the equipment to be reduced by about 14≠ more than this.

As described above, the present invention has an extremely rational intermediate heat medium.1. EJJ is the most efficient, economical, and versatile heat exchanger available.
It can be applied to vaporizers in terms of heat transfer, and therefore has a simpler configuration compared to conventional vaporizers, and can perform efficient vaporization in a smaller heat transfer area, allowing for easy installation. Make the space smaller! Both of the four methods have the characteristics of being easy to put into practical use and reducing construction costs. Furthermore, the present invention has the feature that running costs can be completely reduced because heating media at room temperature such as seawater or river water can be used as they are without any problems, and by adjusting the intermediate heating medium, vaporized natural Another feature is that it also adjusts the amount of heat in the gas.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are explanatory diagrams showing the overall configuration of an apparatus to which the present invention is applied. 1 shell and tube heat exchanger, 2... liquefied natural gas introduction section, 3 liquefied natural gas outlet section, 4 intermediate heat medium, 5.
・Introduction part for intermediate heat medium, 6. Derivation part, 7. Heating medium, 8. Introduction part for heating medium, 9 Derivation part, 10. Circulation pump, 11. Receiver, 12.. Demister, 13.
Heater, S...shell side, T/tube side, R/circulation system, a...natural circulation route, b...forced circulation route, C pressure equalization pipe. Fig. 2 3 2 3 - γ0 6 ・ [ 2 bites 2 in 2, b ・R 11 -

Claims (1)

[Claims] A liquefied natural gas inlet is provided at the lower part of one side of the shell side or tube side of the shell and tube heat exchanger, and a vaporized natural gas outlet is provided at the upper part. Liquefaction characterized in that an introduction part and a discharge part for the intermediate heating medium are provided which are connected to a circulation system, and an introduction part and a discharge part for the heating medium are provided on the other side of the shell 1μ] 1 or the tube side. Natural gas vaporization equipment