JPH0256560B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LNG vaporizer for vaporizing liquefied natural gas (LNG).

[Prior art] LNG vaporizers can be roughly divided into the following three types.

(1) Open rack vapor riser This method passes LNG through the finch tube.
Seawater is poured over this to exchange heat, and it is commonly used to supply city gas.

(2) SMV (submerged vapor riser) In this method, as shown in Figure 3, LNG heat transfer tube group 01 is installed in water tank 02, and heat for LNG vaporization is supplied by submerged gas burner 03. The high temperature combustion gas generated by the gas burner 03 is transferred to the downcomer 04.
It is guided to the sparge pipe 05 through the sparge pipe 05, and is ejected from the bottom of the water tank 02. The combustion gas directly exchanges heat with water and circulates the hot water using the gas ejection energy to cool the LNG inside the heat transfer tube group 01.
is heated and vaporized.

(3) IFV (Intermediate Medium Vaporizer) In this system, as shown in Figure 4, the vaporizer consists of an intermediate heat medium vaporizer 06, an LNG vaporizer 07, and an NG superheater 08. It is filled with hydrocarbon or fluorocarbon as an intermediate heat medium 09, and a heat transfer group 01 of seawater pipes is installed at the bottom.
0 is placed. Then, the intermediate heat medium 09 in the shell is heated by the seawater 011 and vaporized, and this vaporized intermediate heat medium 09 heats the LNG vaporizer 07 to vaporize the LNG supplied into the pipe. The LNG thus vaporized is sent to a super heater 08, where it is heated to room temperature by seawater 011 and then sent out.

[Problems with conventional technology]

The conventional vaporization method described above has the following problem regarding (2).

Since the submargined gas burner 03 is placed underwater, it may not ignite at startup due to the influence of moisture, or it may take a long time to ignite, so that it may not be ready in time for an emergency.

Regarding (3), the initial cost is high because it requires ancillary equipment such as a seawater pump and seawater supply/drainage equipment, and since the seawater side is not an open type for heat exchange, the system may be affected by adhesion of shellfish or freezing phenomena. The interior is easily clogged and requires careful maintenance.

Note that (1) is not directly related to the present invention and will therefore be omitted here.

[Object of the present invention]

An object of the present invention is to provide an LNG vaporizer that can be activated immediately to respond to emergencies and to reduce the initial cost of the equipment.

[Structure of the present invention and its operation]

The configuration of the present invention is as follows.

A first shell that is filled with water leaving a space in the upper part of the shell, a gas burner for heating the water and a first waste heat exchanger are installed in the water, and a super heater is installed in the upper space. ,
A space is left in the upper part of the shell and filled with an intermediate heat medium, and a second waste heat exchanger for heating the intermediate heat medium by the exhaust heat of the gas burner is installed in the intermediate heat medium, and a second waste heat exchanger is installed in the upper space. A second shell incorporating an LNG vaporizer and a vaporized
an LNG vaporization line that sends LNG from an LNG vaporizer in a second shell through a superheater in a first shell; and an LNG vaporization line that sends LNG from an LNG vaporizer in a second shell through a superheater in a first shell; An LNG vaporizer consisting of an exhaust heat line that discharges outside the vessel via a second exhaust heat exchanger.

In the LNG vaporizer described above, the gas burner can use city gas, for example, and is completely separated from the water filled in this shell in the first shell. The exchange of heat is now taking place. Then, the exhaust gas discharged from the gas burner reaches the second exhaust heat exchanger in the second shell via the first exhaust heat exchanger built in the first shell, where it is exchanged with the intermediate heat medium. During this time, heat is exchanged and then discharged outside the vessel.

Hydrocarbons, fluorocarbons, or the like are used as the intermediate heat medium in the second shell. The intermediate heat transfer medium in the second shell and the water in the first shell are in equilibrium with the steam in the completely degassed shell, and begin to evaporate as soon as they receive heat. For this purpose, an air extraction device is attached to the first and second shells.

Next, the first shell and the second shell may be integrated, for example, the first shell is built into the second shell, or they may be constructed separately. However, in order to exchange heat between the heat of the water in the first shell and the intermediate heat medium in the second shell, a built-in type is used, and the heat is transferred into the second shell through the outer wall of the first shell. Preferably, the intermediate heat medium is heated.

In the present invention, LNG is heated and vaporized by an intermediate heat medium such as saturated CFC vapor generated in the second shell, and this vaporized LNG (NG) is superheated to room temperature by the saturated steam in the first shell. Sent to the consumer.

[Examples and their effects]

FIG. 1 shows an embodiment of the present invention, in which 1 is a sealed first shell;
is filled with water leaving a space 2 inside, and in this water 3 is a gas burner 4 completely isolated from the water 3, and a first waste heat exchanger through which exhaust gas from the gas burner 4 passes. 5 is incorporated, and a super heater (heat exchanger) 6 is further incorporated in the upper space 2.

Reference numeral 7 designates a second shell, and inside the second shell 7, the first shell is incorporated at intervals around the periphery, and a space 8 is left at the top to accommodate an intermediate heat medium (Freon in the embodiment) 9. The space 8 of the second shell 7 is filled with an LNG vaporizer 10.
However, the second exhaust heat exchanger 11 is built into the intermediate heat medium 9.

12 is an LNG vaporization line, and this LNG vaporization line 12 passes through the LNG vaporizer 10 in the second shell 7 and the super heater 6 in the first shell 1, during which time it is completely vaporized and sent to the consumption side. sent to.

13 is a heat exhaust line, and this heat exhaust line 13
The combustion exhaust heat of the gas burner 4 is discharged from the first exhaust heat exchanger 5 in the first shell 1 to the second exhaust heat exchanger 11 in the second shell 7 to the outside of the vessel.

Reference numeral 14 designates a extraction line, and air is sucked from inside the first shell 1 and the second shell 7 by a vacuum pump 15 to form a vacuum inside.

16 is a fuel gas line that supplies fuel gas to the gas burner 4, and 17 is an air supply line that supplies air for combustion by a blower 18.

Next, an operation example of the above embodiment will be explained.

When the gas burner 4 starts combustion in response to a starting signal, the combustion heat is transferred to the water in the first shell 1, and this water 3 evaporates, creating saturated steam in the space 2. Then, the exhaust heat discharged from the gas burner 4 heats the water 3 in the first shell 1 in the first exhaust heat exchanger 5, and then reaches the second exhaust heat exchanger 11 in the second shell 7, where it reaches the second exhaust heat exchanger 11 in the second shell 7. The intermediate heat medium 9 in the second shell 7 is heated, and the intermediate heat medium 9 is evaporated to produce saturated (fluorocarbon) vapor in the space 8.

LNG was sent into the vessel from vaporization line 12.
LNG is vaporized by absorbing saturated fluorocarbon vapor heat in the LNG vaporizer 10 in the second shell 7, and furthermore, this vaporized LNG (NG) also absorbs saturated vapor heat in the super heater 6 in the first shell 1. It is then heated to room temperature and sent out.

In addition, in the example, for vaporization
Gas burner 4 increases or decreases due to increase or decrease in LNG (increase or decrease in load).
Control is performed so that the LNG delivery temperature is always at the set value by increasing or decreasing the combustion load. When the LNG load is high, a large amount of steam in each system condenses and the pressure in the system decreases. Therefore, the intermediate heat medium 9 in the system evaporates, and the temperature decreases.

When the NG delivery temperature falls below the set value due to an increase in the LNG heat load, the fuel control valve 19 opens, increases the amount of fuel gas, and controls the NG delivery temperature to always be maintained at the set value.

FIG. 2 shows another embodiment, namely the first shell and the second shell.
An embodiment in which the shell 7 is separated is shown, and the operation and control thereof are the same as in the previous embodiment.

However, in this embodiment, the intermediate heat medium 9 in the second shell 7 cannot transfer heat from the water 3 through the outer wall of the first shell 1.

[Effects of the present invention]

The present invention comprises a first shell and a second shell as described above, heats water with a gas burner in the first shell to produce saturated steam, and heats an intermediate heat medium with waste heat in the second shell. Saturated steam is created, the LNG to be vaporized is first vaporized in the second shell, and then the temperature is raised to room temperature in the first shell before being sent out, resulting in the following effects.

(1) Since the gas burner is completely isolated from water in the first shell, problems such as the burner not being able to ignite or taking a long time to ignite due to moisture, and being unable to respond in an emergency can be avoided.

(2) The intermediate heat medium is vaporized using waste heat, and this heat is used to vaporize LNG, and no seawater is used at all, so there is no need for any seawater supply/discharge equipment or control equipment. As a result, the initial cost of the vaporizer equipment can be reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a carburetor according to the present invention in which a first shell is incorporated into a second shell, and FIG. 2 is an explanatory diagram of a carburetor according to the present invention in which the first shell and second shell are separated. Figure 3 is an explanatory diagram of SMV, Figure 4 is
It is an explanatory diagram of IFV. 1... First shell, 4... Gas burner, 5... First waste heat exchanger, 6... Super heater, 7... Second shell, 10... LNG vaporizer, 11... Second waste heat exchanger,
12...LNG vaporization line, 13...exhaust heat line.

Claims (1)

[Claims] 1. A space is left in the upper part of the shell and filled with water, and a gas burner and a first waste heat exchanger for heating the water are built into the water, and a super heater is installed in the upper space. a first shell that is assembled into the shell; and a second waste heat exchanger that is filled with an intermediate heat medium leaving a space in the upper part of the shell, and that heats the intermediate heat medium within the intermediate heat medium using the exhaust heat of the gas burner. and a second shell incorporating an LNG vaporizer in the upper space, and sending the vaporized LNG from the LNG vaporizer in the second shell through the superheater in the first shell.
an LNG vaporization line; and an exhaust line that discharges exhaust gas discharged from the gas burner from the first exhaust heat exchanger in the first shell to the outside of the vessel via the second exhaust heat exchanger in the second shell. LNG vaporizer consisting of