JP4625650B2 - Low temperature liquefied gas supply device - Google Patents

Description

The present invention relates to a low-temperature liquefied gas supply device that supplies a low-temperature liquefied gas stored in a storage tank to the demand side after vaporization, and in particular, a novel that can be supplied at low cost by changing the supply mode depending on the amount of consumption during supply. The present invention relates to a low-temperature liquefied gas supply device.

As a conventional example of a low-temperature liquefied gas supply device, one disclosed in Patent Document 1 is known. As shown in FIG. 2, the base end portion of the pressurizing line 2 having the small capacity vaporizer 4 in the liquid phase portion 1a of the low temperature liquefied gas storage tank 1 and the base end portion of the discharge line 3 having the large capacity vaporizer 7 are provided. The pressure line 2 is communicated with the gas phase part 1b of the low-temperature liquefied gas storage tank 1 to pressurize the storage tank 1 to a predetermined pressure or higher, and the high-capacity vaporizer 7 of the discharge line 3 is cooled at a low temperature. The liquefied gas is vaporized and supplied to the demand side.
JP 2003-148695 A (see FIG. 1)

By the way, conventionally, in order to change the supply amount according to the amount of consumption on the demand side, the flow rate is adjusted by a controllable on-off valve 8 provided in the payout line 3. In addition, when the vaporizer 7 of the discharge line 3 performs a heat exchange operation for a long time, frost formation and icing are generated. In order to defrost and defrost, as shown in FIG. Two large-capacity carburetors 7 and 17 are provided, and the other carburetor 17 is stopped while one air temperature carburetor 7 is in operation, so that the devolatilizer 17 is defrosted and defrosted. In addition, the system is configured to alternately operate and stop.
However, when two vaporizers 7 and 17 having a large vaporization capacity are provided side by side, there is a problem that the equipment cost is high.
The present invention has been made in view of such circumstances, and the technical problem thereof is a novel low-temperature liquefaction whose facility cost is relatively low and whose supply mode can be changed depending on the amount of low-temperature liquefied gas consumption. The object is to provide a gas supply device.

In order to solve the above problems, the present invention is configured as follows.
That is, the invention according to claim 1 is, for example, as shown in FIG. 1, a base end portion of a pressurizing line 2 having a small capacity vaporizer 4 in a liquid phase portion 1a of a low temperature liquefied gas storage tank 1 and a large capacity vaporizer. 7 is connected to the base end portion of the discharge line 3, the tip end portion of the pressurization line 2 is connected to the gas phase portion 1 b of the low-temperature liquefied gas storage tank 1 to pressurize the low-temperature liquefied gas storage tank 1 and discharge In the liquefied natural gas supply apparatus configured to vaporize the low-temperature liquefied gas by the large-capacity carburetor 7 of the line 3 and supply it to the demand side, the downstream side of the small-capacity carburetor 4 of the pressurization line 2 and the discharge line 3 is configured to be able to communicate with a demand-side supply destination on the downstream side of the large-capacity carburetor 7 through a low-consumption line 9 provided with a small-capacity heat exchanger 10, so that the amount of consumption on the demand side is high. In the mass supply mode, the low-capacity liquefied gas is output from the large-capacity vaporizer 7 of the discharge line 3. Vaporized configured to supply to the demand side, the amount supply mode consumption is reduced low load operation at the demand side, the small of the pressure line 2 of small capacity carburetor 4 and the low consumption line 9 A low-temperature liquefied gas is vaporized and supplied by the capacity heat exchanger 10.

In the present invention, in the mass supply mode when the consumption on the demand side is large, the small-capacity vaporizer 4 provided in the pressurization line 2 is used to pressurize the low-temperature liquefied gas storage tank 1 and the large-capacity vaporizer in the discharge line 3. 7 vaporizes the low-temperature liquefied gas and supplies it to the demand side. On the other hand, in the low-volume supply mode when the consumption on the demand side is small such as at night, the low-capacity liquefied gas is supplied by the small-capacity vaporizer 4 in the pressurization line 2 and the small-capacity heat exchanger 10 provided in the low-consumption line 9. Vaporize and supply.
As described above, according to the present invention, in order to defrost the frost and freezing of the large capacity carburetor 7 of the payout line 3, as shown in FIG. The high-capacity carburetor 7 may be stopped while the vessel 10 is in operation, and frost formation on the high-capacity carburetor 7 may be defrosted. In other words, the supply mode can be changed depending on the amount of low-temperature liquefied gas consumed, and there is no need to install two vaporizers with large vaporization capacity as in the conventional example, so the equipment cost is relatively low. become.

  Hereinafter, a liquefied natural gas (hereinafter abbreviated as “LNG”) supply apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of the LNG supply apparatus. Reference numeral 1 denotes a relatively small-capacity LNG storage tank (pressure tank) in an LNG supply apparatus that is installed in a factory of a general company and supplies LNG to a fuel for a private generator or boiler as a demand-side LNG load facility. ). The base ends of the pressurization line 2 and the discharge line 3 are connected to the lower part of the LNG storage tank 1 so as to communicate with the liquid phase part 1 a inside the storage tank 1. In addition, you may make the base end part of the payout line 3 into a siphon type, and you may make it communicate with the liquid phase part 1a.

  The pressurization line 2 has a small capacity carburetor 4 and an on-off valve 5 capable of adjusting the flow rate in series in the line from the base end side, and the tip end of the pressurization line 2 is connected to the LNG storage tank 1. Is connected to the gas phase portion 1 b inside the storage tank 1. On the other hand, the payout line 3 includes an open / close valve 6, a large capacity carburetor 7, and a demand-side flow rate adjustable open / close valve 8 in series from the base end side. Is connected to the supply destination in the LNG load facility on the demand side.

  The pressurization line 2 vaporizes the LNG fed to the line 2 from the liquid phase portion 1a of the LNG storage tank 1 by heat exchange with the atmosphere in the small capacity vaporizer 4, and the open / close that can adjust the flow rate of the vaporized LNG. By repayment to the gas phase portion 1b of the LNG storage tank 1 through the valve 5, the LNG in the storage tank 1 is held at a pressure higher than the pressure added to the saturated vapor pressure and the head necessary for sending LNG to the demand side. It is like that.

  The payout line 3 vaporizes the LNG fed from the liquid phase portion 1a of the LNG storage tank 1 to the line 3 by heat exchange with the atmosphere in the high-capacity vaporizer 7, and the flow rate of the vaporized LNG is adjusted by the opening / closing valve 8. Then, it is supplied to the demand side with an appropriate amount. Although not shown, it is preferable to additionally provide a BOG (boil-off gas) transfer / discharge line in association with both lines 2 and 3.

In such an LNG supply device, a small capacity carburetor is provided for the downstream side of the small capacity carburetor 4 in the pressurization line 2 and the demand side supply destination on the downstream side of the large capacity carburetor 7 in the discharge line 3. 4 is a low-capacity heat exchanger 10 that warms a low-temperature gas to room temperature and a flow-controllable on-off valve 11 that is connected in series from the upstream side of the LNG flow. In the case of operation in a small amount supply mode, which will be described later, connected by the consumption line 9, the small capacity vaporizer 4 of the pressurization line 2 and the small capacity heat exchanger 10 of the low consumption line 9 After the LNG is vaporized, the flow rate of the vaporized LNG can be adjusted by the on-off valve 11 and supplied to the demand side in an appropriate amount.

  The apparatus shown in FIG. 1 is configured to send a large capacity LNG supplied from the payout line 3 and a small capacity LNG supplied from the low consumption line 9 to the same demand side supply destination. As shown in part by broken lines in FIG. 1, each demand-side supply destination may be provided separately for exclusive use.

  Next, the operation of the LNG supply device of this embodiment will be described. When the demand side is in a large supply mode of high load operation with a large amount of LNG consumption such as during the daytime, the flow rate adjustable on-off valve 11 is fully closed and the LNG fed from the liquid phase part 1a of the LNG storage tank 1 to the discharge line 3 Is vaporized by heat exchange with the atmosphere in the high-capacity carburetor 7, and the flow rate of the vaporized LNG is adjusted by the on-off valve 8 and supplied to the demand side in an appropriate amount, whereby normal LNG supply is achieved. Here, the pressure inside the LNG storage tank 1 is such that the LNG fed to the pressurization line 2 is vaporized by heat exchange with the atmosphere in the small capacity carburetor 4 and the flow rate of the vaporized LNG is adjusted by the on-off valve 5 to adjust the LNG. By paying back to the gas phase portion 1b of the storage tank 1, it is possible to pressurize and maintain the LNG in the storage tank 1 at a pressure higher than an appropriate pressure necessary for sending it out to the demand side.

  When the demand side is in a low-load operation small amount supply mode in which the amount of LNG consumption is low, such as at night, the on-off valve 8 is fully closed based on a control signal issued in response to the change of the supply mode, and the on-off valve 11 is At the same time, the delivery of the payout line 3 is stopped, and at the same time, a small amount of LNG is supplied through the low consumption line 9. In this case, the on-off valve 5 of the pressurizing line 2 can control the flow rate so that the LNG vaporized while maintaining an appropriate pressure from the payout line 3 can be fed to the low consumption line 9. That is, after the LNG is vaporized by the small-capacity carburetor 4 of the pressurization line 2 and the small-capacity heat exchanger 10 of the low-consumption line 9, the flow rate of the vaporized LNG is adjusted by the on-off valve 11 to be appropriate. It can be supplied to the demand side in quantity.

  In this way, the high-capacity carburetor 7 that has been disconnected from the LNG supply system and stopped while performing the operation in the small-volume supply mode is free from frosting that has occurred during the long-time heat exchange operation. It is intended to prepare for the next operation by recovering the heat exchange capacity by performing defrosting and thawing processes for freezing. During operation in the small-volume supply mode, the small capacity carburetor 4 and the small capacity heat exchanger 10 that are connected in series can sufficiently cope with a small amount of LNG consumption. Compared with the large-capacity carburetor 7, a much smaller heat exchanger is sufficient, and there is an advantage that the equipment cost is relatively low.

  In the above embodiment, the LNG supply device is exemplified as the low-temperature liquefied gas supply device. However, the present invention can be widely applied to supply devices such as liquid nitrogen, liquid hydrogen, and liquid oxygen in addition to liquefied natural gas.

It is a schematic block diagram which shows the liquefied natural gas supply apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the example of the conventional liquefied natural gas supply apparatus. It is a schematic block diagram which shows the other examples of the conventional liquefied natural gas supply apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Low temperature liquefied gas storage tank, 1a ... Liquid phase part, 1b ... Gas phase part,
2 ... Pressure line 3 ... Discharge line 4 ... Small capacity vaporizer,
5 ... Open / close valve, 6 ... Open / close valve, 7 ... High capacity carburetor,
8 ... Open / close valve, 9 ... Low consumption line, 10 ... Small capacity heat exchanger,
11 ... Open / close valve,

Claims (1)

In the liquid phase part (1a) of the low-temperature liquefied gas storage tank (1), the base end part of the pressure line (2) having a small capacity vaporizer (4) and the discharge line (3) having a large capacity vaporizer (7) The base end is connected, and the tip of the pressurizing line (2) is communicated with the gas phase part (1b) of the low temperature liquefied gas storage tank (1) to pressurize the low temperature liquefied gas storage tank (1), In the low-temperature liquefied gas supply apparatus configured to vaporize the low-temperature liquefied gas by the large-capacity vaporizer (7) of the discharge line (3) and supply it to the demand side, the small-capacity vaporizer (2) of the pressurization line (2) ( The downstream side of 4) communicates with the demand side supply destination downstream of the large capacity carburetor (7) of the payout line (3) through a low consumption line (9) provided with a small capacity heat exchanger (10). In the large-volume supply mode of high load operation, which is configured to be possible and the consumption on the demand side is large, the low-capacity liquefied gas is vaporized and supplied to the demand side by the large capacity vaporizer (7) of the discharge line (3). In the small supply mode of low load operation where the consumption on the demand side is reduced , the small capacity carburetor (4) of the pressurization line (2) and the small capacity heat exchange of the low consumption line (9) are configured. A low-temperature liquefied gas supply device characterized in that a low-temperature liquefied gas is vaporized and supplied by a vessel (10).