WO2015194774A1

WO2015194774A1 - Liquefied gas treatment system and method for driving same

Info

Publication number: WO2015194774A1
Application number: PCT/KR2015/005586
Authority: WO
Inventors: 강민호
Original assignee: 현대중공업 주식회사
Priority date: 2014-06-18
Filing date: 2015-06-03
Publication date: 2015-12-23

Abstract

A liquefied gas treatment system and a method for driving the same, according to the present invention, drives or puts a high-pressure pump on standby according to an LNG supply standby time during a standby mode so as to efficiently operate the high-pressure pump consuming a large amount of electric power, thereby reducing power consumption.

Description

Liquefied gas treatment system and method of driving the same

The present invention relates to a liquefied gas treatment system and a method of driving the same.

A ship is a means of transporting the ocean carrying large quantities of minerals, crude oil, natural gas, or thousands of containers. It is made of steel and is buoyant and floats on the water surface by buoyancy. Go through.

These vessels generate thrust by driving the engine, where the engine uses gasoline or diesel to move the piston so that the crankshaft is rotated by the reciprocating movement of the piston, whereby the shaft connected to the crankshaft rotates to drive the propeller. It was common to make it possible.

Recently, however, an LNG LNG supply method using an LNG as an LNG to drive an engine has been used in an LNG carrier carrying Liquefied Natural Gas. It is also applied to other ships.

In general, LNG is known to be clean LNG and abundant in reserves than petroleum, and its use is rapidly increasing with the development of mining and transportation technology. It is common to store LNG in liquid state by reducing the temperature of methane, the main component, below -162 degrees under 1 atm, and the volume of liquefied methane is about 600% of the volume of gaseous methane in the standard state. Is 0.42, which is about one half of the share of crude oil.

However, the temperature and pressure required to run the engine may be different from the state of LNG stored in the tank. Therefore, in recent years, continuous research and development has been made on a technology for supplying an engine by controlling the temperature and pressure of LNG stored in a liquid state.

SUMMARY OF THE INVENTION The present invention has been made to improve the prior art, and an object of the present invention is to induce stable and fast driving of an engine in a standby mode in which a fuel supply system is changed from an oil mode to a gas mode, and to reduce power consumption of a pump. It is to provide a liquefied gas treatment system and a method of driving the same.

Liquefied gas processing system according to the present invention, the boosting pump for supplying the liquefied gas stored in the storage tank; A high pressure pump for pressurizing the liquefied gas supplied from the boosting pump; A first recovery line connected to the storage tank in the high pressure pump to recover liquefied gas; A second recovery line for recovering the liquefied gas to the storage tank downstream of the high pressure pump; And a controller for waiting for operation of the high pressure pump when the standby mode lasts for more than a predetermined time.

In detail, when the standby mode is started, the controller operates both the boosting pump and the high pressure pump to recover liquefied gas to the storage tank through the second recovery line, and the standby mode exceeds a preset time. In this case, the high pressure pump may be operated in operation and the liquefied gas may be recovered to the storage tank through the first recovery line.

In detail, the fuel supply line may further include a fuel supply line connected to the demand destination from the storage tank, and the second recovery line may be connected to the storage tank downstream of the high pressure pump on the fuel supply line.

Specifically, the first recovery line comprises a first valve for performing the opening or closing; And a second valve formed as a three-way valve at a point where the second recovery line and the fuel supply line are connected to each other.

Specifically, when the standby mode is started, the controller closes the fuel supply line between the high pressure pump and the demand destination through the second valve, opens the second recovery line, and the standby mode is a preset time. When exceeding, the second recovery line and the fuel supply line between the high-pressure pump and the demand destination through the second valve may be closed, and the first recovery line may be opened.

In detail, the controller may recover the liquefied gas by opening the first recovery line or opening the second recovery line according to the standby mode time.

Specifically, when the standby mode is less than the preset time after the start of the standby mode time, the controller may block the downstream of the high pressure pump and open the second recovery line to recover the liquefied gas.

Specifically, when the standby mode is longer than the preset time, the controller may block the outlet of the high pressure pump and open the first recovery line to recover the liquefied gas.

The method for driving a liquefied gas treatment system according to the present invention includes supplying liquefied gas stored in a storage tank to a demand destination through a boosting pump or a high pressure pump; Performing a standby mode for waiting for supply of liquefied gas to the demand destination; Recovering the liquefied gas introduced into the high pressure pump to a storage tank; When the standby mode holding time is more than the predetermined time, characterized in that it comprises the step of waiting for the operation of the high-pressure pump when the standby mode time elapsed more than the predetermined time.

Specifically, when the standby mode is terminated, the method may further include restarting the supply of the liquefied gas to the demand destination by restarting the high pressure pump.

In detail, the recovering the liquefied gas introduced into the high pressure pump to the storage tank may block the downstream of the high pressure pump to recover the liquefied gas to the storage tank.

Specifically, in the standby mode of waiting for the supply of the liquefied gas to the demand destination, operation of the boosting pump and the high pressure pump may be maintained.

Specifically, when the standby mode is longer than a preset time, the step of waiting for the operation of the high pressure pump, the operation of the boosting pump is maintained, the operation of the high pressure pump may be waiting.

Specifically, when the standby mode is longer than a preset time, the step of waiting for the operation of the high pressure pump, the liquefied gas flowing into the high pressure pump through the boosting pump may be recovered to the storage tank.

Specifically, when the standby mode is less than a predetermined time may further include the step of resuming the supply of liquefied gas to the demand destination when the standby mode is terminated.

The liquefied gas treatment system and a method for driving the same according to the present invention can drive or wait for a high pressure pump according to a standby time for supplying LNG in a standby mode, thereby efficiently operating a high pressure pump with high power consumption, thereby reducing power consumption. It works.

In addition, the present invention has the effect of enabling the stable and rapid supply of gas to the customer by maintaining the operation without stopping the devices driving the gas mode in the standby mode to change from the oil mode to the gas mode.

1 is a conceptual diagram illustrating a liquefied gas supply mode of a liquefied gas treatment system according to an embodiment of the present invention.

Figure 2 is a conceptual diagram showing a high pressure pump of the liquefied gas treatment system according to an embodiment of the present invention.

3 is a conceptual diagram illustrating a standby mode of a liquefied gas treatment system according to an exemplary embodiment of the present invention.

4 is a conceptual diagram illustrating a standby mode of a liquefied gas treatment system according to an exemplary embodiment of the present invention.

5 is a flowchart of a method of driving a liquefied gas treatment system according to an embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram showing a liquefied gas supply mode of the liquefied gas treatment system according to an embodiment of the present invention, Figure 2 is a conceptual diagram showing a high pressure pump of the liquefied gas treatment system according to an embodiment of the present invention, Figure 3 4 is a conceptual diagram illustrating a standby mode of a liquefied gas treatment system according to an embodiment of the present invention, and FIG. 4 is a conceptual diagram illustrating a standby mode of a liquefied gas treatment system according to an embodiment of the present invention.

1 to 4, the liquefied gas treatment system 100 includes a storage tank 10, a demand destination 20, a boosting pump 131, a high pressure pump 132, a heat exchanger 50, and a controller ( 140). Hereinafter, in the present specification, the liquefied gas may be used for the purpose of encompassing not only NG (Natural Gas), which is a liquid state, but also NG, which is a supercritical state.

The liquefied gas treatment system 100 causes the boosting pump 131 to pressurize the liquefied gas discharged from the storage tank through the fuel supply line 21 to several tens to tens of bar, and then the high pressure pump 132 receives the demand source 20. Pressurized to the liquefied gas at a pressure (for example 200bar to 400bar) required to supply to the heat exchanger (50). Thereafter, the heat exchanger 50 may increase the temperature of the liquefied gas supplied from the pump 30 and then supply the liquefied gas in the supercritical state to the demand destination 20. In this case, the liquefied gas supplied to the demand destination 20 may have a pressure of 200 bar to 400 bar and a supercritical state having a temperature of 30 to 60 degrees.

As shown in FIG. 1, a fuel supply line 21 may be installed between the storage tank 10 and the demand destination 20, and a boosting pump 131 may be installed at the fuel supply line 21. The high pressure pump 132 and the heat exchanger 50 may be provided to supply the liquefied gas to the demand destination 20.

In this case, a fuel supply valve (not shown) is installed in the fuel supply line 21, and the supply amount of the liquefied gas may be adjusted according to the opening degree of the fuel supply valve, and the fuel supply line 21 may be described above. As described above, the liquefied gas that is adjusted to the temperature and pressure conditions required by the demand destination 20 may be supplied from the storage tank 10 to the demand destination 20 so that the demand destination 20 may be driven.

Specifically, the storage tank 10 stores the liquefied gas to be supplied to the demand destination 20. Storage tank 10 is to be stored in a liquid state of the liquefied gas, in which the storage tank 10 may have a pressure tank form. The storage tank 10 may be formed of a stainless steel material of the double tank structure, between the double tank structure is provided with a heat insulating portion (which may be a vacuum state), and withstands a pressure of 5bar to 10bar (for example 6bar) It can be designed to be.

The demand destination 20 is driven through the liquefied gas supplied from the storage tank 10 to generate thrust. In this case, the demand source 20 may be a MEGI engine as an engine, or a dual fuel engine.

When the engine 20 is a dual fuel engine, LNG and oil may be selectively supplied without being mixed with LNG and oil. This is to prevent two materials having different combustion temperatures from being mixed and supplied, thereby preventing the efficiency of the engine 20 from decreasing.

As the engine 20 reciprocates the piston (not shown) inside the engine cylinder (not shown) by the combustion of LNG, a crank shaft (not shown) connected to the piston is rotated and connected to the crank shaft. A shaft (not shown) can be rotated. Accordingly, when the engine 20 is driven, a propeller (not shown) connected to the shaft finally rotates, and the hull moves forward or backward.

In this embodiment, the engine 20 may be an engine 20 for driving a propeller, but the engine 20 may be an engine 20 for power generation or an engine 20 for generating other power, and the like. .

The boosting pump 131 may be provided on the fuel supply line 21 between the storage tank 10 and the high pressure pump 132, so that a sufficient amount of liquefied gas is supplied to the high pressure pump 132 so as to supply a high pressure pump ( Cavitation of the 132 is prevented. In addition, the boosting pump 131 may extract the liquefied gas from the storage tank 10 to pressurize the liquefied gas within a few to several tens of bar, and the liquefied gas passed through the boosting pump 131 may be pressurized to 1 bar to 25 bar.

The liquefied gas stored in the storage tank 10 is in a liquid state. At this time, the boosting pump 131 may pressurize the liquefied gas discharged from the storage tank 10 to increase the pressure and temperature to some extent, and the liquefied gas pressurized by the boosting pump 131 may still be in a liquid state.

On the other hand, the liquefied gas processing system 100 of the present embodiment can be used as fuel (oil, for example, diesel), although not shown in the drawings, can be used by converting the fuel from diesel and liquefied gas, liquefied gas to diesel. . Here, when the fuel is converted from diesel to liquefied gas, or restarted after stopping, it may be operated in a standby mode, which will be described in the driving method.

The high pressure pump 132 pressurizes the liquefied gas discharged from the boosting pump 131 to a high pressure so that the liquefied gas is supplied to the engine 20. The liquefied gas is discharged from the storage tank 10 at a pressure of about 1 bar to 10 bar and then pressurized primarily by the boosting pump 131. The high pressure pump 132 is in a liquid state pressurized by the boosting pump 131. The liquefied gas is secondarily pressurized and supplied to the heat exchanger 50 to be described later or to the first recovery line 135 or the second recovery line 235.

At this time, the high-pressure pump 132 pressurizes the liquefied gas required by the demand source 20, for example, 200 bar to 400 bar, and supplies the demand destination 20 to the demand destination 20 so as to produce thrust through the liquefied gas. can do.

As shown in FIG. 2 (side view of the high pressure pump), the high pressure pump 132 drives a piston 1322 and a motor 1323 for reciprocating the cylinder 1321 and the cylinder 1321. It may be made of. In addition, the high pressure pump 132 may further include a sealing member 1324 provided on the circumferential surface of the piston 1322 to prevent the outflow of the liquefied gas that flows in and out of the cylinder 1321.

On the other hand, when the demand source 20 is driven by oil (diesel), the high pressure pump 132 is stopped and the liquefied gas in the high pressure pump 132 is in constant contact with the room temperature, so that the temperature of the sealing member 1324 is also high. Can be elevated.

For example, when the standby mode is started, when the cryogenic liquefied gas flows into the high pressure pump 132 to cool down when the high pressure pump 132 is stopped, unlike when the boosting pump 131 is driven, the high pressure pump ( The sealing member 1324 of 132 may be cooled. At this time, the sealing member 1324 may be damaged by cold heat.

In order to prevent this, the high pressure pump 132 may further include a heat source member, and the heat source member may transfer heat when the driving of the piston 1322 is waiting to prevent damage of the sealing member 1324. On the other hand, when the piston 1322 is driven, frictional heat generated by the inner wall of the cylinder 1321 is generated, so that heat does not need to be transferred separately, and thus the heat source member may stop driving.

The heat source member may be formed of a heating coil 1325, the heating coil 1325 is disposed to cover one end surface of the sealing member 1324, and the heating coil 1325 is in contact with the sealing member 1324 to generate heat. By supplying, damage by cold heat can be prevented.

In contrast, the heat source member may supply the N2 gas or heat generated from a heat source (for example, an engine) generated in the liquefied gas treatment system 100 to the sealing member 1324.

In this embodiment, the boosting pump 131 and the high pressure pump 132 may be controlled by the controller 140 to be described later in the standby mode, and the first recovery line 135 and the second recovery line 235 in the standby mode. Through the liquefied gas may be recovered to the storage tank (10).

That is, as shown in FIG. 3 (the solid line shows the flow of liquefied gas), the first recovery line 135 is connected between the storage tank 10 and the high pressure pump 132 to store the liquefied gas upstream. The tank 10 is recovered. The first recovery line 135 is connected to the inside of the high pressure pump 132 to recover the liquefied gas to the storage tank 10 in the standby mode before the liquefied gas is discharged to the outlet of the high pressure pump 132. Accordingly, the first recovery line 135 may allow the high pressure pump 132 to cool down by the liquefied gas in the standby mode in the process of being recovered to the storage tank 10 by the liquefied gas via the high pressure pump 132. have.

In the present embodiment, when recovering the liquefied gas through the first recovery line 135, the high pressure pump 132 may be in the operating standby state, at this time, the boosting pump to cool down the inlet of the high pressure pump 132 The liquefied gas discharged from 131 may be recovered from the interior of the high pressure pump 132 to the storage tank 10 via the high pressure pump 132.

Here, the first valve 136 is installed on the first recovery line 135, the first valve 136 may be made of a general valve, the boosting pump 131 and the high pressure pump 132 is cool down operation In this case, the first recovery line 135 is opened to allow LNG in the high pressure pump 132 to flow into the storage tank 10.

On the other hand, as shown in Figure 4 (solid line shows the flow of liquefied gas), the second recovery line 235 is branched downstream of the high-pressure pump 132 on the fuel supply line 21 to the storage tank 10 In this way, the liquefied gas discharged from the high pressure pump 132 may be recovered to the storage tank 10. The second recovery line 235 may recover the liquefied gas discharged by being pressed by the high pressure pump 132 to the storage tank 10.

Here, a second valve 236 may be provided on the fuel supply line 21 where the second recovery line 235 or the second recovery line 235 is branched, and the second valve 236 may be a general valve or three-way. It may consist of a valve. When the standby mode is operated, the second valve 236 closes the downstream of the fuel supply line 21 and opens the second recovery line 235 to store the liquefied gas discharged from the outlet of the high pressure pump 132. Let it flow into (10).

In the present exemplary embodiment, the first recovery line 135 and the second recovery line 235 are individually connected to the storage tank 10, but the second recovery line 235 is connected to the first recovery line 135. The embodiments may be otherwise accomplished as joined.

The controller 40 may selectively open the first recovery line 135 and the second recovery line 235. This is to adjust the operation of the boosting pump 131 or the high pressure pump 132 and the recovery of the liquefied gas according to the standby mode time when the standby mode is executed.

For example, the controller 140 drives both the boosting pump 131 and the high pressure pump 132 when the standby mode holding time is less than a preset time (for example, 30 minutes), and through the second recovery line 235. The liquefied gas is recovered to the storage tank 10. In addition, when the standby mode time is more than the preset time (for example, 30 minutes), the driving of the boosting pump 131 may be maintained, but the operation of the high pressure pump 132 may be waited for operation. This is to minimize power consumption by waiting for operation of the high-pressure pump 132 that consumes a lot of power when the standby mode is executed for more than a predetermined time.

At this time, the controller 140 opens the second recovery line 235 so that the liquefied gas is discharged after being pressurized by the high pressure pump 132 when the standby mode time is less than the preset time (for example, 30 minutes). . On the contrary, when the standby mode time is executed for more than a preset time (for example, 30 minutes), the high pressure pump 132 is in the standby state of operation, and thus does not need to be discharged from the outlet of the high pressure pump 132. Opening the 135 may recover the liquefied gas to the storage tank 10.

The controller 140 may be divided into a case in which the standby mode is specified to be less than the preset time and a case in which the standby mode is designated to be above the preset time.

First, when the standby mode is designated (maintained) below the preset time, for example, when the standby mode is designated as less than 30 minutes (that is, 10 minutes, 15 minutes, 20 minutes, 25 minutes, etc.) will be described below.

When the standby mode is performed for less than a preset time (for example, 30 minutes), for example, when the standby mode is maintained for 20 minutes, both the boosting pump 131 and the high pressure pump 132 are driven, and the demand source 20 ) The side flow and the first recovery line 135 are closed, but the second recovery line 235 is opened to circulate the liquefied gas so that the boosting pump 131 and the high pressure pump 132 are kept cool down. At the same time, the state of the liquefied gas can continuously maintain the pressure required by the demand source 20.

When the standby mode is terminated after being executed for less than a preset time (for example, 30 minutes), that is, when the standby mode is terminated after maintaining the standby mode for 20 minutes, for example, the boosting pump 131 and the high pressure pump 132. Since the boosting pump 131 and the high pressure pump 132 are continuously cooled down while the state of the liquefied gas is continuously maintained at the pressure required by the demand destination 20 by being driven continuously, When the standby mode is terminated, the liquefied gas may be supplied to the demand source 20 immediately.

As a result, the liquefied gas treatment system 100 according to the embodiment of the present invention has the effect of enabling the stable and rapid supply of liquefied gas to the demand destination 20, and the effect of enabling the rapid change of the oil mode and the liquefied gas mode. There is.

In the following, when the standby mode is designated (maintained) for more than the preset time, for example, when the standby mode is specified for 30 minutes or more (that is, 30 minutes, 35 minutes, 40 minutes, 45 minutes, etc.) will be described below.

When the standby mode is executed for a preset time (for example, 30 minutes) or more, for example, when the standby mode is maintained for 40 minutes, the boosting pump 131 and the high pressure pump 132 may be turned on until the preset time is 30 minutes. By driving all, the flow of the demand destination 20 and the first recovery line 135 are closed, but the second recovery line 235 is opened to circulate the liquefied gas, so that the boosting pump 131 and the high pressure pump 132 continue to cool down. The state of the liquefied gas is maintained at the same time, and the state of the liquefied gas is continuously maintained. The pressure of the high pressure pump 132 is stopped after 30 minutes, which is the preset time, and the boosting pump 131 is maintained. By operating only the bay to close the second recovery line 235 and open the first recovery line 135, the liquefied gas is circulated to keep the boosting pump 131 and the high pressure pump 132 only in the cool down state. do.

In this case, the operation of the high-pressure pump 132 that consumes high power is waited, thereby preventing waste of power, and the boosting pump 131 is continuously operated so that the boosting pump 131 and the high pressure pump 132 are operated. As it continues to cool down, immediate operation of the high pressure pump 132 can be accomplished at any time.

As a result, in the embodiment of the present invention, there is no need to perform a separate cooldown, thereby enabling immediate fuel supply to the demand destination 20, and maximizing driving flexibility of the oil mode and the liquefied gas mode.

The heat exchanger 50 is provided on the fuel supply line 21 between the high pressure pump 132 and the demand destination 20 to supply the liquefied gas to the demand destination 20 when the demand destination 20 is driven after the end of the standby mode. The liquefied gas discharged from 132 can be heated by a method such as steam.

The liquefied gas may be supplied to the heat exchanger 50 by the high pressure pump 132, and the heat exchanger 50 heats the liquefied gas while maintaining the pressure of 200 bar to 400 bar discharged from the high pressure pump 132. The engine 20 may be supplied to the engine 20 after being converted to the supercritical state of FIGS.

Such an embodiment may prevent damage of the sealing member 1324 due to cold heat by transferring heat to the sealing member 1324 when the high pressure pump 132 is in the standby mode, and according to the standby mode time. By driving or waiting for the high pressure pump 132, the power consumption can be reduced by efficiently operating the high pressure pump 132 with high power consumption.

Hereinafter, a method of driving the liquefied gas treatment system through the liquefied gas treatment system 100 as described above will be described. Duplicate descriptions of the same functions and actions according to the configuration of the above-described embodiments will be omitted.

As shown in FIG. 5, in the method for driving a liquefied gas treatment system according to an exemplary embodiment of the present invention, a liquefied gas stored in the storage tank 10 is required through a boosting pump 131 or a high pressure pump 132. Supplying (20) (S110); Performing the standby mode for waiting for supply of liquefied gas to the demand source (20) (S120); Recovering the liquefied gas introduced into the high pressure pump 132 to the storage tank 10 (S130); Waiting for the operation of the high pressure pump 132 when the standby mode time elapses after the preset time, when the standby mode holding time is longer than the preset time (S140); When the standby mode is terminated, restarting the high pressure pump 132 to resume supply of liquefied gas to the demand destination 20 (S151) and when the standby mode holding time is less than a preset time, the standby mode When the step is terminated, and the supply of the liquefied gas to the demand source 20 includes a step (S152).

This embodiment is intended to reduce power consumption due to the high-pressure pump 132 with high power consumption when the standby mode is performed for a predetermined time or more. For example, the standby mode is made for 2 hours or less for the sake of understanding and explanation. do. In this case, whether the boosting pump 131, the high pressure pump 132, and the opening of the first and

second recovery lines

135 and 235 are changed by the controller 140 according to the cooldown time is the liquefied gas of the above-described embodiment. It is the same as or similar to the processing system 100.

In step S110, the liquefied gas stored in the storage tank 10 is supplied to the demand destination 20 through the boosting pump 131 or the high pressure pump 132. The contents of supplying the liquefied gas stored in the storage tank 10 to the demand destination 20 are replaced with those described above.

In step S120, the standby mode for waiting for supply of the liquefied gas to the demand destination 20 is performed.

In the case where supply of the demand source 20 of the liquefied gas that has been performed in step S100 is stopped, for example, when the oil is supplied to the demand source 20, the supply of the liquefied gas is stopped. When liquefied gas flows again after stopping the operation of the liquefied gas treatment system 100, such as when restarting, when the liquefied gas is continuously contacted to room temperature and flowed into the demand destination 20, Since it is not possible to perform stable operation because it does not meet the proper conditions required by 20), it operates the standby mode to stop the supply of liquefied gas because the efficiency of operation may be lowered.

In the embodiment of the present invention, the operation of the boosting pump 131 and the high pressure pump 132 in the standby mode is continuously driven without interruption.

The blocking of the liquefied gas supplied to the demand destination 20 may be achieved by blocking the second valve 236 connected to the downstream of the high pressure pump 132 or the fuel supply line 21 connected to the downstream of the high pressure pump 132. This can optionally be done by the standby mode time.

The standby mode hold time may be limited, for example, to a total of 2 hours or less, with the standby mode hold time being initially (in the range of 30 minutes or less from the start of the first standby mode, preferably standby mode) and later (second time). Standby mode, preferably in the range of 30 minutes from the standby mode after 30 minutes).

The initial and late stages correspond to steps S130 and S140, which will be described later, and will be described later.

In step S130, the liquefied gas introduced into the high pressure pump 132 is recovered to the storage tank 10. This step S130 may be a standby mode initial step.

As shown in FIG. 4 (solid line shows circulation of the liquefied gas), at the initial stage of the standby mode, the boosting pump 131 and the high pressure pump 132 are cooled down, and the liquefied gas is the demand destination 20. It may have the temperature and pressure conditions required by the customer 20 before it is supplied to. At this time, in the present invention, the coolant can be achieved by blocking the flow of the demand source 20 side, which opens the second recovery line 235 through the second valve 236 and supplies the fuel supply line (to the demand source 20 side). 21) can be achieved by closing and controlling the flow of liquefied gas. Here, the second recovery line 235 is connected downstream of the high pressure pump 132 to recover the liquefied gas pressurized by the high pressure pump 132 to the storage tank 10.

Unlike the standby mode holding time (2 hours) described in the present embodiment, even if the standby mode is abruptly stopped in this initial stage and the liquefied gas is to be supplied to the demand destination 20, the liquefied gas is the boosting pump 131 and Since the high pressure pump 132 always satisfies the pressure and conditions required by the demand source 20, the liquefied gas may be immediately supplied to the demand destination 20, thereby enabling quick response.

In this case, step S152 is performed when the standby mode holding time is less than the preset time (for example, 30 minutes).

In step S152, when the standby mode holding time is less than the preset time, the supply of the liquefied gas to the demand destination is resumed when the standby mode ends.

At this time, the first recovery line 135 and the second recovery line 245 are blocked by the first valve 136 and the second valve 236 to stop the circulation of the liquefied gas, and flows to the heat exchanger 50 The flow of the liquefied gas is opened so that the liquefied gas heat exchanged in the heat exchanger 50 can be supplied to the demand destination 20. In this case, since the liquefied gas always satisfies the pressure and conditions required by the demand source 20 by the boosting pump 131 and the high pressure pump 132, the liquefied gas can be immediately supplied to the demand destination 20, thereby providing a quick response. This is possible.

In step S140, when the standby mode holding time is equal to or greater than the preset time, the standby mode time is waited for the operation of the high pressure pump 132 after the preset time is longer than the preset time. This step S140 is a late step of the standby mode, and may be a step in which the standby mode has elapsed 30 minutes or more. At this time, the boosting pump 131 is still in operation so that the liquefied gas circulates through the storage tank, the boosting pump 131, and the high pressure pump 132, and the high pressure pump 132 is in a standby state. As a result, the power consumption may be minimized by waiting for the high pressure pump 132 that consumes a lot of power in preparation for the boosting pump 131.

On the other hand, as shown in FIG. 3 (the solid line shows the circulation of the liquefied gas), in the late standby mode, when the high pressure pump 132 is switched to the standby state, the liquefied gas moves to the outlet of the high pressure pump 132. It does not need to be discharged through. Accordingly, when the standby mode is longer than the preset time, the outlet of the high pressure pump 132 is blocked to block the supply of the liquefied gas to the demand destination 20, and the boosting pump 131 flows through the liquefied gas through the high pressure. It may be circulated through the first recovery line 135 before the outlet of the pump 132. In this case, the second recovery line 235 and the fuel supply line 21 may be closed.

That is, in this case, the liquefied gas is circulated by the storage tank 10, the boosting pump 131, and the high pressure pump 132 by the fuel supply line 21 and the first recovery line 135 by the boosting pump 131. The cool down may be maintained, and the high pressure pump 132 may minimize power consumption in a state where standby operation is performed.

In step S151, when the standby mode is terminated, the high pressure pump 132 is restarted to resume supply of the liquefied gas to the demand destination 20. When the standby mode is terminated, that is, when the late standby mode is terminated (after two hours have elapsed), supply of the liquefied gas to the demand destination 20 is resumed.

At this time, the first recovery line 135 and the second recovery line 245 are blocked by the first valve 136 and the second valve 236 to stop the circulation of the liquefied gas, and flows to the heat exchanger 50 The flow of the liquefied gas is opened so that the liquefied gas heat exchanged in the heat exchanger 50 can be supplied to the demand destination 20.

As described above, the present embodiment, for example, when switching fuel from oil to liquefied gas, operates the standby mode to cool down the boosting pump 131 and the high pressure pump 132, and accordingly, the high pressure pump 132 according to the standby mode time. ) Can control the driving and standby to reduce the waste of power, and to achieve a stable operation can improve the efficiency of the operation.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and should be understood by those skilled in the art within the technical spirit of the present invention. It is obvious that the modifications and improvements are possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

Claims

A boosting pump for supplying liquefied gas stored in the storage tank;

A high pressure pump for pressurizing the liquefied gas supplied from the boosting pump;

A first recovery line connected to the storage tank in the high pressure pump to recover liquefied gas;

A second recovery line for recovering the liquefied gas to the storage tank downstream of the high pressure pump; And

And a control unit for waiting for operation of the high pressure pump when the standby mode lasts for more than a predetermined time.
The method of claim 1, wherein the control unit,

When the standby mode is started, by operating both the boosting pump and the high pressure pump to recover the liquefied gas to the storage tank through the second recovery line,

The liquefied gas treatment system, characterized in that when the standby mode is exceeded a predetermined time, the high-pressure pump is put into operation and the liquefied gas is recovered to the storage tank through the first recovery line.
The method of claim 2,

Further comprising a fuel supply line connected to the demand destination from the storage tank,

And the second recovery line is connected to the storage tank downstream of the high pressure pump on the fuel supply line.
The method of claim 3, wherein

The first recovery line includes a first valve for performing opening or closing; And

At the point where the second recovery line and the fuel supply line is connected, the liquefied gas treatment system further comprises a second valve formed of a three-way valve.
The method of claim 4, wherein the control unit,

When the standby mode is started, closes the fuel supply line between the high pressure pump and the demand destination through the second valve, opens the second recovery line,

When the standby mode exceeds a preset time, the fuel supply line between the second recovery line and the high pressure pump and the demand destination is closed through the second valve, and the first recovery line is opened. Liquefied gas treatment system.
The method of claim 1, wherein the control unit,

Liquefied gas treatment system characterized in that to recover the liquefied gas by opening the first recovery line or by opening the second recovery line according to the standby mode time.
The method of claim 2, wherein the control unit,

When the standby mode is less than the predetermined time from the start of the standby mode time, the downstream of the high-pressure pump is blocked, and the second recovery line is opened to recover the liquefied gas.
The method of claim 2, wherein the control unit,

When the standby mode is more than a predetermined time, the outlet of the high-pressure pump is shut off and the liquefied gas recovery system to recover the liquefied gas by opening the first recovery line.
Supplying the liquefied gas stored in the storage tank to the demand through a boosting pump or a high pressure pump;

Performing a standby mode for waiting for supply of liquefied gas to the demand destination;

Recovering the liquefied gas introduced into the high pressure pump to a storage tank;

And waiting for operation of the high pressure pump when the standby mode time is greater than or equal to the preset time, when the standby mode time is longer than the preset time.
The method of claim 9,

And when the standby mode ends, restarting the high pressure pump to resume the supply of liquefied gas to the demand destination.
The method of claim 9, wherein recovering the liquefied gas introduced into the high pressure pump to the storage tank,

And recovering the liquefied gas to the storage tank by blocking a downstream of the high pressure pump.
10. The method of claim 9, wherein the performing of the standby mode for waiting for supply of liquefied gas to the demand destination comprises:

And operating the boosting pump and the high pressure pump.
The method of claim 9, wherein when the standby mode holding time is greater than or equal to a preset time, waiting for the operation of the high pressure pump when the standby mode time exceeds the preset time comprises:

Operation of the boosting pump is maintained and operation of the high pressure pump is waited.
The method of claim 13, wherein when the standby mode holding time is greater than or equal to a preset time, waiting for the high pressure pump to operate when the standby mode time is greater than the preset time,

And liquefied gas flowing into the high pressure pump through the boosting pump is recovered to the storage tank.
The method of claim 9,

Resuming supply of liquefied gas to the demand destination when the standby mode ends when the standby mode holding time is less than a preset time.