KR100678851B1 - Offshore lng regasification system with pressure of suction drum controlled and method for controlling the same - Google Patents

Abstract

An oceanic LNG regasification system having a suction drum controlling a pressure and a method for controlling the same are provided to supply LNG gas at a stable pressure upstream of a high pressure pump and a carburetter by a unit for constantly controlling the pressure in the suction drum. An oceanic LNG regasification system includes a high pressure pump(120), a carburetter(140), a suction drum, and a drum pressure regulating unit. The high pressure pump is installed in an oceanic floating structure so as to raise the pressure of LNG gas to a high pressure. The carburetter evaporates the LNG gas, the pressure of which is raised by the high pressure pump on the oceanic floating structure. The suction drum receives the LNG gas from an LNG storing tank and supplies the LNG gas to the high pressure pump. The drum pressure regulating unit measures the pressure in the suction drum and controls the pressure in the suction drum on the basis of the measured pressure value so as to stably supply the LNG gas to the high pressure pump.

Description

Offshore LNG REGASIFICATION SYSTEM WITH PRESSURE OF SUCTION DRUM CONTROLLED AND METHOD FOR CONTROLLING THE SAME}

1 is a schematic diagram schematically showing a marine LNG regasification system installed in a vessel according to an embodiment of the present invention.

2 is a circuit diagram conceptually illustrating a marine LNG regasification system according to an embodiment of the present invention.

Figure 3 is a block flow diagram illustrating a method for controlling the internal pressure of the suction drum in the marine LNG regasification system according to an embodiment of the present invention.

<Code Description of Main Parts of Drawing>

101: LNG storage tank 110: suction drum

120: high pressure pump 140: vaporizer

11: drum pressure control unit 112: drum pressure controller

113: drum pressure sensor 114, 115: drum pressure control valve

The present invention recovers offshore LNG to supply natural gas in a regasified gas state after regasification (ie, regasification) of Liquified Natural Gas (LNG) in a floating structure such as a ship. More specifically, the present invention relates to a marine LNG regasification system including a suction drum for temporarily storing liquefied natural gas to be regasified and providing the liquefied natural gas to a carburetor at a stable pressure, and a control method thereof. will be.

In recent years, the consumption of natural gas is rapidly increasing worldwide. Natural gas is transported in a gaseous state through onshore or offshore gas piping, or to a remote consumer while stored in an LNG carrier (especially an LNG carrier) in the form of liquefied natural gas. Liquefied natural gas is obtained by compressing and cooling natural gas to cryogenic temperature (approximately -160 ℃), and its volume is reduced to approximately 1/600 than that of natural gas in gas state, so it is very suitable for long distance transportation through sea.

The LNG Carrier is designed to unload liquefied natural gas to the land requirements by loading the liquefied natural gas into the sea, and for this purpose, an LNG storage tank (commonly referred to as a 'cargo') that can withstand the cryogenic temperature of the liquefied natural gas. It includes. Normally, such LNG transport ships unload liquefied natural gas in LNG storage tanks as they are liquefied, and the unloaded LNG is regasified by LNG regasification facilities installed on land and then transported through gas piping to consumers of natural gas. do.

Such onshore LNG regasification facility is known to be economically advantageous when installed in a place where there is a demand for natural gas because the natural gas market is well formed. However, in the case of natural gas demand where the demand for natural gas is seasonal, short-term or periodic, it is economically disadvantageous to install LNG regasification facilities on land due to the high installation cost and management cost.

In particular, if a land LNG regasification facility is destroyed due to a natural disaster or the like, even if an LNG carrier arrives at a required destination, the LNG cannot be regasified. Holding it.

As a result, for example, an offshore LNG regasification system has been developed in which an LNG regasification facility is provided on an LNG carrier to regasify liquefied natural gas at sea and supply natural gas obtained through regasification to the land. In addition, the prior art related to the offshore LNG regasification system include Korean Patent Registration No. 0569621 (ExxonMobil Oil Corporation, method and system for gasifying liquefied natural gas on a ship), US6546739 (Exmar Offshore Company, Method and apparatus for offshore LNG) regasification, US6578366, Moss Maritime AS, Device for evaporation of liquefied natural gas, US6688114, El Paso Corporation LNG CARRIER, US6598408, El Paso Corporation, Method and apparatus for transporting LNG, KR0467963 Device operation method), US6945049 (Hamworthy KSE as, Regasification system and method), Korean patent registration 0504237 (Daewoo Shipbuilding & Marine Engineering Co., Ltd., vessel equipped with shielding means to block the bottom opening), Korean patent registration 0474522 (Daewoo Shipbuilding & Marine Engineering Co., Ltd.) , Seawater heating system), Korean Patent Publication No. 2003-0090686 (Life Hoeg und CO.A.S., Ship and unloading system) , US Patent Publication US2005-0061002A (Shipboard regasification for LNG carriers with alternate propulsion plants), Korean Patent Publication No. 2004-0105801 (Excelate Energy Limited Partnership, Improved LNK Carrier), Korea Utility Registration 0410836 (Samsung Heavy Industries Co., Ltd. Liquefied natural gas regasification system of gas line).

This offshore LNG regasification system is equipped with facilities such as a vaporizer on the vessel for regasification of the liquefied natural gas stored in the LNG storage tank, and also to supply the regasified natural gas to the land requirements, And a connecting device for connecting the gas pipes to the land requirements, and a ship holding device for maintaining the position of the ship while the natural gas is unloaded.

In the marine LNG regasification system as described above, the offshore vessel is responsible for the regasification of liquefied natural gas, eliminating the need for LNG regasification facilities on land, which means that the demand for natural gas is seasonal, short-term, or periodically. Economically very advantageous in the natural gas market.

However, such offshore LNG regasification systems are not suitable for onshore LNG regasification systems due to various constraints caused by their location in offshore floating structures such as ships (e.g., depending on the location and / or installation space of the sea). In contrast, the inventors have found that the operation is inferior in stability. In particular, for the stable regasification operation of liquefied natural gas, the liquefied natural gas in the LNG storage tank must be supplied at a stable pressure upstream of the high pressure pump and its downstream vaporizer, which is directly liquefied from the LNG storage tank or the like. When the natural gas is supplied to the high pressure pump, it has been found by the present inventors that the supply pressure pressure control of the tank or other storage means is not easy, and thus the stable supply of the liquefied natural gas is not available.

It is therefore an object of the present invention to provide a marine LNG regasification system capable of supplying liquefied natural gas at a stable pressure toward a high pressure pump and a downstream vaporizer and a control method thereof. In addition, the technical problem of the present invention can be solved by providing a suction drum which is provided between the LNG storage tank and the high pressure pump to supply liquefied natural gas at a stable, more preferably, substantially constant pressure. Control of such a suction drum is preferably made in an automatic control method.

According to one aspect of the invention, installed in the offshore floating structure, by regasifying the liquefied natural gas (LNG) stored in the LNG storage tank, offshore LNG regasification to supply the regasified natural gas (NG) to land requirements A system is provided. An offshore LNG regasification system according to an aspect of the present invention includes a high pressure pump installed in the offshore floating structure to boost the liquefied natural gas (LNG) to a high pressure; A vaporizer for vaporizing liquefied natural gas boosted by the high pressure pump on the marine floating structure; A suction drum receiving the liquefied natural gas from the LNG storage tank and temporarily storing the liquefied natural gas; In order to supply a stable liquefied natural gas to the high-pressure pump, the pressure in the suction drum is measured, and the drum pressure control unit for controlling the pressure in the suction drum based on the measured pressure value.

According to one embodiment of the invention, the drum pressure control unit, the drum pressure sensor for measuring the pressure in the suction drum, and the first installed to exhaust and suck the natural gas in the suction drum present with liquefied natural gas And a drum pressure controller for controlling the pressure in the suction drum to a predetermined pressure by controlling the first and second drum pressure regulating valves based on a second drum pressure regulating valve and the measured pressure in the suction drum. Include.

At this time, the first drum pressure control valve is preferably installed in the first return flow path of the natural gas (NG) from the suction drum to the LNG storage tank to reduce the pressure in the suction drum. In addition, the second drum pressure control valve is preferably installed in a second return flow path of natural gas (NG) from the pipe downstream of the vaporizer to the suction drum to increase the pressure in the suction drum.

In addition, the marine LNG regasification system according to the present embodiment, further comprises a means for measuring the level (height) of the liquefied natural gas in the suction drum and control the height of the suction drum to a predetermined height according to the measured level value Include. In addition, the marine LNG regasification system according to the present embodiment further comprises a means for measuring the operating flow rate of the high-pressure pump and constantly controlling the operating flow rate of the high-pressure pump according to the measured operating flow rate value.

According to another aspect of the present invention, receiving the liquefied natural gas stored in the LNG storage tank of the offshore floating structure in the suction drum and temporarily storing it and supplying it to the high pressure pump, the liquefied natural gas (LNG) in the high pressure pump The control method of the offshore LNG regasification system for supplying to the vaporizer by supplying to the carburetor, regasifying the liquefied natural gas from the vaporizer to supply the natural gas (NG) of the regasified gas state to the land requirements, such a The control method includes the steps of: (a) measuring the pressure in the suction drum; (b) determining whether the pressure value measured in the suction drum is a predetermined proper pressure; (c) adjusting the pressure in the suction drum to the predetermined appropriate pressure when the measured pressure value is out of the proper pressure; Include.

Example

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

1 shows an offshore LNG regasification system according to an embodiment of the present invention. As shown in Fig. 1, the system 100 of the present embodiment is installed on a ship 2, and the liquefied natural gas is regasified to natural gas in a gas state while the ship 2 is mooring at sea, and then it is on the land. Supply to the required location (not shown). Although the system 100 of the present embodiment is described as being installed in an LNG regasification vessel having a transport function of liquefied natural gas, it may be installed in another offshore floating structure on the sea to receive liquefied natural gas from an LNG carrier and regasify it. It is.

The system 100 of the present embodiment includes an LNG storage tank 101, a suction drum 110 for temporarily storing liquefied natural gas drawn up from the LNG storage tank 101, and the suction drum 110. A plurality of high-pressure pump 120 for pressurizing the supplied liquefied natural gas at a high pressure, and a plurality of vaporizers for regasifying the supplied liquefied natural gas by boosting the pressure from each of the high pressure pump 120 (only one shown) using a heat exchange medium 140. The heat exchange medium may be seawater or fresh water, or an intermediate heat exchange medium (for example, propane, ethane, and amphonia may be used together (as disclosed in US 6945049).

In order to supply the regasified natural gas to the land (that is, unloading), a method using a gas pipe of the seabed or a gas pipe of the ship and a pipe of the land directly (especially a pipe installed on the land quay) without a sea gas pipe. ) May be used. In the present embodiment, the method using the subsea gas piping 7, inter alia, the buoy 4 of the seabed is connected to the turret 3 of the ship, and the buoy 4 is connected to the LNG regasification system 100 on the ship. Submerged Turret Loading (STL) scheme is used, which is connected to the subsea terminal 6 by a riser 9. However, this manner may be modified in various forms and is not intended to limit the present invention.

For example, as in the pipe 7 shown in Fig. 1, a seabed or a land pipe for supplying natural gas to a land source needs fluctuations in the internal pressure due to the natural gas consumption of the destination (hereinafter, Pressure fluctuations in the It is not easy to control the pressure fluctuations of the required destination in the ship, and therefore, it is necessary to cope with such pressure fluctuations and to operate the marine LNG regasification system 100.

2 is a circuit diagram conceptually illustrating an operation concept of a marine LNG regasification system according to the present embodiment.

As shown in FIG. 2, the system 100 of the present embodiment includes a plurality of pressure regulating valves 150 and 150 ′ for adjusting pressure in the system, and a plurality of regulating flow rates of natural gas to be regasified and sent to the land. And a flow control valve 130 (only one is shown).

The flow control valve 130 is an inlet side of each of the plurality of vaporizers 140, in order to adjust the vaporization amount of the liquefied natural gas supplied from the high pressure pump 120, that is, the natural gas supply flow to the land requirements Is located in. In addition, the pressure control valve (150, 150 ') is located downstream of the vaporizer 140, that is, the rear end of the system, serves to adjust the natural gas operating pressure of the system according to the required pressure fluctuations.

The pressure regulating valves 150 and 150 ′ are controlled by the pressure controller 152, and the pressure controller 152 uses the pressure information of the required place where the change is made and the pressure information in the system to control the pressure regulating valve 150. , 150 '). By the action of the pressure controller 152 and the pressure control valve (150, 150 ') controlled by it, the natural gas operating pressure on the vessel can be maintained at a pressure that is appropriately larger than the required pressure.

In the present embodiment, the pressure controller 152, by using the first pressure sensor 153 measures the pressure downstream of the pressure control valve (150, 150 ') that the pressure change occurs according to the pressure change of the required destination Using the measured pressure value, the required pressure information can be obtained. The pressure controller 152 uses the measured pressure value of the second pressure sensor 154 upstream of the pressure regulating valve 150 as pressure information in the system.

As described above, in the marine LNG regasification system 100 of the present embodiment, when there is a pressure fluctuation of the required destination, the pressure regulating valves 150 and 150 'are controlled by the pressure controller 152 so that the system 100 Limit the natural gas operating pressure to be above a certain pressure.

To this end, the pressure controller 152 has a predetermined operating pressure (Pc) of about 70 bar in advance, the pressure controller 152 is required to vary the natural gas operating pressure of the system in response to the required pressure fluctuations In addition, the pressure in the system is always maintained above the preset pressure value Pc.

Further, the pressure controller 152 measures the delivery temperature of the natural gas by using the temperature sensor 156, and the natural gas operating pressure in the system is in advance when the measured delivery temperature of the natural gas is less than a preset set temperature. Restriction of falling below a predetermined set pressure ensures the stability of the regasification operation of the system.

On the other hand, the flow control valve 130 described above controls the flow rate of the natural gas under the control of the flow controller 132, that is, the flow rate of the natural gas sent to the required place after regasification. The flow rate controller 132 controls the flow rate control valve 130 based on the required flow rate of the natural gas required from the driver's input or wired and wireless communication, thereby regasifying the liquefied natural gas, that is, the natural gas output flow rate. Can be adjusted.

The marine LNG regasification system 100 of the present embodiment is adjacent to an upstream side of the pressure regulating valve 150 in order to obtain the flow rate information in the system required for controlling the flow regulating valve 130 by the flow controller 132. The metering unit 133 is located. The metering unit 133 measures the flow rate of natural gas in the system 100 collected in a single pipe after being regasified in the plurality of vaporizers 140. In addition, the system 100 of the present embodiment also includes a plurality of flow meters 134 (only one shown) installed in each of the plurality of vaporizers 140 to individually measure the flow rates of the respective vaporizers 140.

According to the above configuration, the flow rate controller 132 compares the natural gas request flow rate required and the flow rate measured by the metering unit 133, and determines the total increase or decrease of the flow rate according to the comparison result. In addition, the flow controller 132 is a plurality of flow control valve 130 located at the inlet side of each vaporizer 140 by using the flow value information measured by the plurality of flow meters 134 on the basis of the increase and decrease of the entire flow rate Are controlled respectively, and the load of each vaporizer 140 is calculated.

The flow controller 132 increases or decreases the flow rate of the natural gas based on the above-described measured flow rate values and the required flow rate of the required destination, and includes the sensors illustrated in FIG. 2, that is, the pressure sensor 137 and the discharge gas. Using the measured values measured by the temperature sensor 156, the metering unit 133, the discharge seawater temperature sensor 147, and the like to limit the increase of the flow rate. Stable operation of the system (regasification and natural gas supply) is achieved by limiting the flow rate increase under the following conditions.

(1) When the pressure of natural gas sent is more than the preset value,

(2) When the temperature of natural gas sent is less than preset value,

(3) When natural gas delivery speed is more than preset value,

(4) When the heat exchange medium temperature of the vaporizer outlet is less than the preset value.

Now, look at in more detail with respect to the main features of the invention claimed in the claims herein.

The marine LNG regasification system 100 of this embodiment includes a drum pressure regulating unit 11 for controlling the pressure in the suction drum 110 described above. The drum pressure control unit 11 is blocked in a virtual line in Figure 2 for convenience of understanding.

According to an embodiment of the present invention, the drum pressure regulating unit 11 includes a drum pressure controller 112, first and second drum pressure regulating valves 114 and 115, and a drum pressure sensor 110. do. The drum pressure controller 112 receives pressure information in the suction drum 110 from the drum pressure sensor 113 located in the suction drum 110, and thus, the first and second drum pressure regulating valves 114 and 115. To control. The first drum pressure regulating valve 114 may reduce the pressure in the suction drum 100 by returning a portion of the natural gas NG located above the LNG in the suction drum 110 to the LNG storage tank. Can be. In addition, the second drum pressure regulating valve 115 may increase the pressure in the suction drum 100 by returning a part of the natural gas NG sent to the required place back into the suction drum 110.

Accordingly, the drum pressure controller 112 may control the pressure in the suction drum 100 to a predetermined proper pressure range, most preferably, a constant pressure, and through the pressure control in the suction drum 100, suction The liquefied natural gas of the drum 100 may be supplied to the high pressure pump 120 at a stable pressure, most preferably a constant pressure.

3 is a schematic block diagram illustrating a control concept for the pressure control in the suction drum 110 by the drum pressure control unit 11 and the supply of the stable liquefied natural gas to the high pressure pump.

2 and 3 together, the pressure control in the suction drum 110 receives the liquefied natural gas stored in the LNG storage tank 101 from the suction drum 110 and temporarily stores it to the high pressure pump 120. And supplying the liquefied natural gas (LNG) to the high pressure by supplying the vaporized gas to the vaporizer 140 in the high pressure pump 120, and regasifying the liquefied natural gas in the vaporizer 140 This is done automatically during operation of the system 100 for natural gas (NG) regasification and natural gas supply of a series of liquefied natural gas to the land requirements.

Referring to FIG. 3, in order to control the pressure in the suction drum, first, a suitable pressure Ps in the suction drum 110, that is, the natural gas may be supplied to the high pressure pump 120 to the high pressure pump at a substantially constant pressure. The appropriate pressure Ps is set in advance (S301). This is done before system operation unlike other control steps described below. The appropriate pressure Ps may be determined in a range having an upper limit value and a lower limit value, or may be determined as a single pressure value.

After the proper pressure in the suction drum is set, the above-described regasification operation of the liquefied natural gas is performed (S302). During the regasification operation, the drum pressure sensor 113 is used to measure the present pressure value in the suction drum (S303). Then, the drum pressure controller 116 then measures the measured pressure value and the appropriate pressure of the preset suction drum ( Ps) is compared, and through this, it is determined whether the pressure in the suction drum S303 is increased or decreased (S304). According to the determination result, if necessary, the pressure in the suction drum 110 is adjusted (S305). At this time, the pressure reduction in the suction drum 110 is performed by the first drum pressure control valve 114 returning a portion of the natural gas NG filled above the suction drum 110 to the LNG storage tank. In addition, the pressure increase in the suction drum 110 is performed by the part of the natural gas NG discharged after regasification by the second drum pressure regulating valve 115 returns into the suction drum 110. By the pressure control of the suction drum as described above, the liquefied natural gas having a substantially constant pressure can be supplied to the high pressure pump 120.

Referring back to FIG. 2, a drum level controller 116 is provided in the system 100 to control the level of liquefied natural gas in the suction drum 110, and the drum level controller 116 is a suction drum. The level sensor 117 in the 110 receives the level (height) information of the liquefied natural gas in the suction drum 110, and controls the plurality of level control valves 118. By the level control means comprising the above components, the level of the liquefied natural gas in the suction drum 110 can be maintained almost constant, which also helps the stable operation of the present system 100.

In addition, the marine LNG regasification system 100 of the present embodiment is configured to automatically control the operating flow rate of the high-pressure pump 120 above a certain flow rate. To this end, the system 100, the flow rate value measured by the pump flow meter 123 for measuring the flow rate of the liquefied natural gas at the inlet or discharge side of the high-pressure pump 120 or calculated using the current value of the pump It includes a pump flow controller 122 for controlling the minimum operating flow rate of the high pressure pump 120 on the basis. The pump flow controller 122 controls the minimum operating flow rate of the high pressure pump 120 by controlling the pump flow control valve 124 installed in the return flow path leading to the suction drum 110 toward the outlet side of the high pressure pump 120. In particular, the pump flow controller 122 compares the set flow rate value determined as a lower limit value with the measured flow rate value, and when the measured flow rate value is smaller than the set flow rate value, the pump flow rate control valve 124 is opened. By adjusting, the operation flow rate of the high pressure pump 120 is increased to a set flow rate value or more. As a result, the pump flow controller 122. By the above pump flow rate control means including the pump flow meter 123 and the like, the high pressure pump 120 may perform a stable high pressure pumping operation above the minimum flow rate.

While the invention has been described above with reference to specific embodiments, various modifications, changes or modifications may be made in the art within the spirit and scope of the appended claims, and thus, the foregoing description and drawings It should be construed as illustrating the present invention rather than limiting the technical spirit of the present invention.

 According to an embodiment of the present invention, in the LNG offshore regasification system, in supplying liquefied natural gas to a high pressure pump and a vaporizer downstream thereof, the high pressure pump by means of controlling the suction drum and the pressure in the suction drum to be substantially constant. And liquefied natural gas at a stable pressure upstream of the downstream vaporizer. In addition, since the flow rate in the suction drum is kept substantially constant during the regasification operation of the liquefied natural gas, and the operating flow rate of the high pressure pump also remains stable without falling to a predetermined lower limit, the stable offshore LNG regasification operation and thereby stable Onshore supply of natural gas can be implemented.

Claims (10)

In the offshore LNG regasification system installed in the offshore floating structure, regasified liquefied natural gas (LNG) stored in the LNG storage tank, and supplies the regasified natural gas (NG) to the land requirements, A high pressure pump installed at the marine floating structure to boost the liquefied natural gas (LNG) to a high pressure; A vaporizer for vaporizing liquefied natural gas boosted by the high pressure pump on the marine floating structure; A suction drum receiving the liquefied natural gas from the LNG storage tank and temporarily storing the liquefied natural gas; A drum pressure regulating unit for measuring the pressure in the suction drum and controlling the pressure in the suction drum based on the measured pressure value to supply a stable liquefied natural gas to the high pressure pump; Offshore LNG regasification system having a suction drum comprising a. The method of claim 1, wherein the drum pressure control unit, Drum pressure sensor for measuring the pressure in the suction drum, First and second drum pressure regulating valves installed to exhaust and suck natural gas in the suction drum present with liquefied natural gas; A drum pressure controller for controlling the pressure in the suction drum to a predetermined pressure by controlling the first and second drum pressure regulating valves based on the measured pressure in the suction drum;  Offshore LNG regasification system having a suction drum comprising a. The method of claim 2, wherein the first drum pressure regulating valve is installed in the first return flow path of natural gas (NG) from the suction drum to the LNG storage tank to reduce the pressure in the suction drum, The second drum pressure regulating valve is installed on the second return flow path of natural gas (NG) from the pipe downstream of the vaporizer to the suction drum to increase the pressure in the suction drum. Regasification system. The method according to any one of claims 1 to 3, further comprising means for measuring the level (height) of the liquefied natural gas in the suction drum and controlling the height of the suction drum to a predetermined height according to the measured level value. Offshore LNG regasification system having a suction drum, characterized in that.  The suction device according to any one of claims 1 to 3, further comprising means for measuring the operating flow rate of the high pressure pump and controlling the operating flow rate of the high pressure pump constantly according to the measured operating flow rate value. Offshore LNG Regasification System with Drum. Receive the liquefied natural gas stored in the LNG storage tank of the offshore floating structure from the suction drum and temporarily store it and supply it to a high pressure pump, and boosts the liquefied natural gas (LNG) to a high pressure from the high pressure pump to supply to the vaporizer, As a control method of a marine LNG regasification system which regasifies liquefied natural gas in a vaporizer and supplies natural gas (NG) of regasified gas state to a land site, (a) measuring the pressure in the suction drum; (b) determining whether the pressure value measured in the suction drum is a predetermined proper pressure; (c) adjusting the pressure in the suction drum to the predetermined appropriate pressure when the measured pressure value is out of the proper pressure; Control method of offshore LNG regasification system comprising a. The offshore LNG regasification system according to claim 6, wherein the step (c) returns natural gas (NG) in the suction drum to the LNG storage tank to adjust the pressure in the suction drum. Control method. The offshore LNG regasification method according to claim 6, wherein the step (c) comprises returning the natural gas (NG) sent to the land requirement to the suction drum for adjusting the pressure in the suction drum. Control method of the system. The method of claim 6, further comprising measuring a level (height) of the liquefied natural gas in the suction drum and controlling the height of the suction drum to a predetermined height according to the measured level value. A method of controlling an offshore LNG regasification system.  The method according to any one of claims 6 to 8, further comprising the step of measuring the operating flow rate of the high pressure pump and controlling the operation flow rate of the high pressure pump in accordance with the measured operating flow rate constant. Control method of LNG regasification system.

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