JPH07109476A - Apparatus for adjusting heating value of natural gas - Google Patents

Abstract

PURPOSE:To prevent the delivery of a natural gas(NG) of a high heating value from being delivered at the re-start of operation in an adjusting apparatus of heating value of NG. CONSTITUTION:A purge line 11 fitted with a purge control valve 12 is provided downstream of an emergency shut-off valve 10 in an LPG feed line 5, and when the operation is stopped, the emergency shut-off valve 10 is shut, the purge control valve 12 is immediately opened to purge the remaining LPG from the system through the purge line 11 by the pressure of the NG, and an operation control valve 9 is then shut by means of a controller 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a calorific value adjusting device for natural gas.

[0002]

Liquefied natural gas (hereinafter referred to as "LNG")
When the natural gas with a stable calorific value (hereinafter referred to as “NG”) is vaporized and the NG is vaporized, a liquefied petroleum gas with a high calorific value (hereinafter referred to as “LPG”) is mixed with the vaporized NG.

2 to 4 show a conventional heat quantity adjusting device of this type, which is supplied from an LNG supply line 1.
Is led to the LNG vaporizer 2 and vaporized there, and the vaporized NG is passed from the NG line 3 to the plate fin type NG superheater 4
Be led to.

On the other hand, LPG supplied for heat quantity adjustment is L
It is guided to the bottom of the superheater 4 via a PG supply line 5, and passes through a header tank 6 provided at the bottom of the superheater 4 and an injection tube 7 inserted from the header tank 6 into the superheater 4. It is injected into the superheater 4, where it is vaporized and simultaneously mixed with NG to adjust the heat quantity of NG to a constant heat quantity. And the NG of which the amount of heat is adjusted
Is sent to the consumer side via the NG sending line 8.

In the heat quantity adjusting device thus operated, when the operation is stopped, the LPG supply line 5
Stop the emergency shutoff valve 10 attached to the
The method of closing the operation control valve 9 attached to the NG supply line 1 is adopted.

[0006]

Therefore, the following drawbacks occur.

A. When the operation is stopped, as described above, LPG
Since LNG is stopped after first stopping, injection tube 7, header tank 6, emergency shutoff valve 1
LPG remains in the LPG supply line 5 on the downstream side of 0, and the remaining LPG is vaporized during the operation stop and becomes rich in oil gas in the superheater 4, and when restarting, NG with a high heat amount is consumed. Sent to.

An object of the present invention is to provide a high heat quantity N at restart.
It is to propose a heat quantity adjusting device for natural gas that does not deliver G.

[0009]

The structure of the heat quantity adjusting device for natural gas according to the present invention is as follows.

The natural gas vaporized by the liquefied natural gas vaporizer is guided to a heat quantity adjusting natural gas superheater, and the liquefied petroleum gas injected for heat quantity adjustment adjusts the heat quantity to a predetermined heat quantity and sends it to the consumer side. In the heat quantity adjusting device, the purge line is provided by branching the downstream side of the emergency shutoff valve attached to the liquefied petroleum gas supply line, and the tip is connected to the vent stack line diffusion line and the purge control valve is attached to the purge line. This purge control valve is controlled to be closed during operation, the emergency shutoff valve is first closed when operation is stopped, and immediately after that, the purge control valve is opened to remain in the system due to the pressure of natural gas introduced into the superheater. A heat regulation device for natural gas, which is provided with a controller for purging liquefied petroleum gas and then stopping the supply of liquefied natural gas to stop the operation.

[0011]

[Operation] LNG supplied from the LNG supply line by opening the operation control valve is introduced into the LNG vaporizer and vaporized, and then introduced into the NG superheater from the bottom of the NG superheater via the NG line. To be done.

On the other hand, the LPG for adjusting the amount of heat supplied from the LPG supply line by opening the emergency shutoff valve is introduced from the header tank to the bottom of the NG superheater through the injection tube and vaporized in the NG superheater. At the same time, it is mixed with NG, and thereby the heat quantity of NG is adjusted.

NG whose heat quantity is adjusted in the NG superheater is N
It is sent to the consumer side via the G sending line. During the above operation, the purge control valve of the purge line is closed.

Next, when the operation of the heat quantity adjusting device is stopped, the controller first closes the emergency shutoff valve, and immediately after that, opens the purge control valve to inject the injection tube with the NG pressure introduced into the superheater. And header tank and LPG
The LPG remaining in the supply line is purged outside the system via the purge line. The purged LPG is processed via the vent stack row diffusion line.

[0015]

Embodiments of the present invention will be described in detail with reference to FIG.
Reference numeral 1 is an LNG supply line with an operation control valve 9 and 2 is L
NG vaporizer (double pipe type), 3 NG line, 4 plate fin type NG superheater, 5 LPG with emergency shutoff valve 10
A supply line, 6 is a header tank provided at the bottom of the superheater 4, 7 is an injection tube inserted from the header tank 6 into the superheater 4, and 8 is NG whose heat quantity is adjusted by the superheater 4 is sent to the consumer side. NG transmission line.

Reference numeral 11 designates a purge line with a purge control valve 12 which branches off the downstream side of the emergency shutoff valve 10 of the LPG supply line 5, and the tip of this purge line 11 is connected to a vent stack row diffusion line (not shown). ing.

Numeral 13 is a controller, and this controller 13 controls the heat quantity adjusting device as follows.

When the operation is stopped, first, the emergency shutoff valve 1
0 is closed, and immediately after that, the purge control valve 12 is opened. As a result,
Due to the pressure of the NG introduced into the superheater 4, the LPG remaining in the injection tube 7 and the header tank 6 flows backward in the LPG supply line 5, and is discharged from the purge line 11 via the vent stack row diffusion line. To be done. This purging usually takes a few tens of seconds, so
Next, the purge control valve 12 is closed, and immediately after that, the operation control valve 9 is closed to stop the operation.

The heat quantity adjustment of the embodiment is a so-called feedback control method in which the heat quantity of NG sent from the NG sending line 8 is measured to control the injection amount of LPG.

[0020]

As described above, according to the present invention, when the operation is stopped, N
The LPG remaining in the injection tube and header tank in the G superheater and in the LPG supply line is purged outside the system by the pressure of the NG introduced into the NG superheater, and then the LNG is stopped. Vaporize N
The inside of the G heater does not become rich in oil gas. As a result, NG with a high calorific value is not delivered at the time of restart.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a heat quantity adjusting device embodying the present invention.

FIG. 2 is an explanatory diagram of a conventional heat quantity adjusting device.

FIG. 3 is an explanatory view showing a lower portion of a conventional NG heater.

FIG. 4 is an explanatory view of the inside of an NG heater and a header tank.

[Explanation of symbols]

 1 LNG supply line 2 LNG vaporizer 3 NG line 4 NG heater 5 LPG supply line 6 Header tank 7 Injection tube 8 NG delivery line 9 Operation control valve 10 Emergency shutoff valve 11 Purge line 12 Purge control valve 13 Controller

Front page continuation (72) Inventor Toshiyasu Miura 38-37-402 Shirahatagami-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Shinichi Kasahara 6-9-5-28, Ota-ku, Tokyo (72) Inventor Akiyama Yu 2-12-1-3 Sorakudai, Kizu-cho, Soraku-gun, Kyoto (72) Inventor Masayuki Moriyama 133-44 Nono-cho, Sakai-shi, Osaka

Claims (1)

[Claims] 1. A natural gas vaporized by a liquefied natural gas vaporizer is led to a heat quantity adjusting natural gas superheater, and the liquefied petroleum gas injected for heat quantity adjustment is adjusted to a predetermined heat quantity and then sent to a consumer side. In the natural gas heat regulation device, a purge line is provided by branching the downstream side of the emergency shutoff valve attached to the liquefied petroleum gas supply line, and the tip is connected to the vent stack line diffusion line and the purge control valve is connected to the purge line. This purge control valve is installed and controlled to be closed during operation.When the operation is stopped, the emergency shutoff valve is closed first, and immediately after that, the purge control valve is opened to remain in the system due to the pressure of natural gas introduced into the superheater. A calorific value adjusting device for natural gas, which is provided with a controller for purging the liquefied petroleum gas that is being used, and then stopping the operation by stopping the supply of the liquefied natural gas.