WO2023100231A1 - Liquefied gas receiving facility and control method for same - Google Patents

Liquefied gas receiving facility and control method for same Download PDF

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Publication number
WO2023100231A1
WO2023100231A1 PCT/JP2021/043817 JP2021043817W WO2023100231A1 WO 2023100231 A1 WO2023100231 A1 WO 2023100231A1 JP 2021043817 W JP2021043817 W JP 2021043817W WO 2023100231 A1 WO2023100231 A1 WO 2023100231A1
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WIPO (PCT)
Prior art keywords
liquefied gas
pump
delivery
line
flow rate
Prior art date
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PCT/JP2021/043817
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French (fr)
Japanese (ja)
Inventor
修 安達
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日揮グローバル株式会社
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Application filed by 日揮グローバル株式会社 filed Critical 日揮グローバル株式会社
Priority to PCT/JP2021/043817 priority Critical patent/WO2023100231A1/en
Priority to JP2022544270A priority patent/JP7155460B1/en
Publication of WO2023100231A1 publication Critical patent/WO2023100231A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/03—Stopping, starting, unloading or idling control by means of valves
    • F04B49/035—Bypassing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Definitions

  • the present invention relates to a liquefied gas receiving facility that receives liquefied gas, stores it in a liquefied gas tank, and delivers the liquefied gas from a delivery line, and a control method thereof.
  • Liquefied natural gas Liquefied Natural Gas
  • LPG Liquefied Petroleum Gas
  • other liquefied gases are used in the liquid state for storage and transportation because their volume is smaller than that in the gaseous state.
  • a minimum flow is set in order to prevent overheating, vibration, etc. due to an insufficient flow rate.
  • Patent Literature 1 describes branching a minimum flow line from a liquefied gas supply line using a high-pressure pump unit to enable continuous operation of the high-pressure pump unit.
  • Patent Document 2 describes estimating the primary side pressure from the measured value of the secondary side flow rate and the secondary side pressure in an unbalanced pressure reducing valve used in a gas supply system.
  • multiple pumps may be installed in the storage tank in order to increase the transport capacity of the pump or as a backup against pump failure. If a minimum flow line is provided for each pump, it will be necessary to install facilities and equipment attached to the minimum flow line for each pump.
  • An object of the present invention is to provide a liquefied gas receiving facility and a control method thereof that can simplify the minimum flow line facility and reduce costs.
  • a first aspect of the present invention includes a liquefied gas tank for storing liquefied gas, a delivery line for delivering the liquefied gas from the liquefied gas tank in a liquid state, and a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line. and a minimum flow line branching from the payout line and capable of returning the liquefied gas to the liquefied gas tank;
  • the pump suction pressure of the delivery pump below the liquid level of the liquefied gas is calculated from the density and liquid level of the stored liquefied gas and the gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank.
  • the liquefied gas receiving facility is characterized in that the minimum flow of the delivery pump is controlled using the pump suction pressure and the pump performance curve of the delivery pump.
  • the control system includes, in the pump performance curve, a pressure converted to a head corresponding to a minimum flow rate required to maintain the delivery pump, and the pump suction pressure Estimate the pump discharge pressure at the minimum flow rate, compare the estimated value of the pump discharge pressure with the measured value of the pump discharge pressure measured in the payout line, and compare the measured value of the pump discharge pressure with the measured value of the pump discharge pressure
  • the flow rate of the minimum flow line is increased, and when the measured value of the pump discharge pressure is lower than the estimated value of the pump discharge pressure, the flow rate of the minimum flow line is decreased.
  • the control system uses the actual value of the pump discharge pressure measured in the payout line, the pump suction pressure, and the pump performance curve to determine the determining an estimated flow rate in a payout line, and if the estimated flow rate is less than the minimum flow rate required to maintain the delivery pump, increasing the flow rate in the minimum flow line, wherein the estimated flow rate is less than the estimated flow rate required to maintain the delivery pump; is more than the minimum flow rate, the flow rate of the minimum flow line is reduced.
  • the liquefied gas receiving equipment includes two or more delivery pumps and the two or more delivery pumps for the same liquefied gas tank. and a payout line shared with the same liquefied gas tank, wherein the minimum flow line includes a miniflow valve disposed therein, and the control system, when activating any of the two or more delivery pumps, actuates the other in the same liquefied gas tank.
  • the control system when activating any of the two or more delivery pumps, actuates the other in the same liquefied gas tank.
  • the liquefied gas is allowed to flow through the mini-flow valve to the minimum flow line for a predetermined time after the first delivery pump is activated.
  • a pressure indicator controller for the liquefied gas is arranged in the delivery line, and the control system controls the pressure value of the pressure indicator controller and the mini
  • the flow rate in the miniflow valve is calculated from the capacity coefficient of the flow valve, and it is determined whether or not the minimum flow is maintained.
  • control system increases the flow rate in the miniflow valve when the calculated value of the flow rate in the miniflow valve is insufficient to maintain the minimum flow.
  • control system when activating any one of the two or more delivery pumps, controls other delivery pumps in the same liquefied gas tank.
  • the total flow rate downstream of the payout line is calculated, and this total value is used to maintain minimum flow for the newly started and running pumps. It is characterized by determining whether it is sufficient or not.
  • control system when activating any one of the two or more delivery pumps, controls other delivery pumps in the same liquefied gas tank.
  • the liquefied gas is allowed to flow through the mini-flow valve to the minimum flow line for a predetermined time after the start of the newly started delivery pump.
  • a ninth aspect of the present invention is a liquefied gas tank for storing liquefied gas, a delivery line for delivering the liquefied gas from the liquefied gas tank in a liquid state, and a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line. and a minimum flow line branching from the delivery line and capable of returning the liquefied gas to the liquefied gas tank, wherein the liquefied gas stored in the liquefied gas tank.
  • a control method for a liquefied gas receiving facility characterized in that the minimum flow of the delivery pump is controlled using the pressure and the pump performance curve of the delivery pump.
  • the first aspect it is possible to control the minimum flow of the delivery pump without installing a flow meter in the dispensing line or attaching a flow meter to each pump. Therefore, the equipment of the minimum flow line can be simplified and the cost can be reduced. In addition, operating costs can be reduced by setting the optimum minimum flow value according to fluctuations in the liquid level and liquid density caused by receiving and discharging liquefied gas.
  • control is optimized to control the minimum flow by comparing the measured value of the pump discharge pressure in the payout line with the estimated value of the pump discharge pressure.
  • control is optimized to control the minimum flow by comparing the minimum flow required to maintain the delivery pump to the estimated flow in the payout line.
  • the minimum flow is ensured on the assumption that the flow rate is low for a predetermined period of time after the first start-up of the delivery pump, which facilitates control.
  • the flow rate in the minimum flow line can be increased or decreased depending on the situation to control the flow rate more than necessary, and the operating cost can be reduced.
  • the minimum flow can be maintained more reliably by calculating the flow rate in the miniflow valve.
  • the minimum flow can be more reliably maintained by increasing the flow rate based on the calculated value of the flow rate in the miniflow valve.
  • the flow rates of the delivery pumps in operation are the minimum flow of the delivery pumps in operation and the minimum flow of the delivery pumps to be activated after the second delivery pump.
  • the eighth aspect even when the second and subsequent delivery pumps are started, the minimum flow is ensured on the assumption that the flow rate is low for a predetermined time after the delivery pump is started, so control becomes easy. . After a predetermined time has passed since the startup, the flow rate in the minimum flow line can be increased or decreased depending on the situation to control the flow rate more than necessary, and the operating cost can be reduced.
  • the ninth aspect it is possible to control the minimum flow of the delivery pump without installing a flow meter in the dispensing line or attaching a flow meter to each pump. Therefore, the equipment of the minimum flow line can be simplified and the cost can be reduced. In addition, operating costs can be reduced by setting the optimum minimum flow value according to fluctuations in the liquid level and liquid density caused by receiving and discharging liquefied gas.
  • FIG. 1 is a schematic diagram showing a first embodiment of a liquefied gas receiving facility
  • FIG. 4 is a schematic diagram showing a second embodiment of a liquefied gas receiving facility
  • It is an explanatory view showing an example of a pump performance curve.
  • FIGS. 1 and 2 An embodiment of a liquefied gas receiving facility 100 is shown in FIGS. These embodiments are provided with the same configuration except for the illustration of the downstream side where the liquefied gas 11 is paid out. Therefore, the configuration common to FIGS. 1 and 2 may be described without distinguishing between the embodiments.
  • the liquefied gas receiving facility 100 includes a liquefied gas tank 10 that stores the liquefied gas 11, a delivery pump 12 that delivers the liquefied gas 11, a delivery line 20 for the liquefied gas 11, a minimum flow line 23, and a control system 30. Prepare.
  • the liquefied gas 11 is a fluid obtained by liquefying a substance that is gas at normal temperature and normal pressure by compression, cooling, or the like.
  • a substance that can be the liquefied gas 11 is not particularly limited, but may be an organic substance or an inorganic substance, and may be a single substance or a mixture. Specific examples include natural gas, petroleum gas, synthetic gas, low-grade (about C1 to C4) hydrocarbons, hydrogen (H 2 ), ammonia (NH 3 ), oxygen (O 2 ), nitrogen (N 2 ), and air. etc.
  • the liquefied gas tank 10 is a container that stores the liquefied gas 11.
  • the liquefied gas tank 10 may be an above-ground type, an underground type, or a semi-underground type.
  • the liquefied gas 11 in the liquefied gas tank 10 may include a gas phase portion 11a on the top portion 10a side of the liquefied gas tank 10 .
  • the liquefied gas tank 10 is provided with a receiving line for receiving the liquefied gas 11 from a tanker or the like.
  • the delivery pump 12 is installed from the top 10a of the liquefied gas tank 10 toward the bottom 10b.
  • a discharge portion 12 a of the delivery pump 12 is installed on the top portion 10 a of the liquefied gas tank 10 .
  • a suction portion 12 b of the delivery pump 12 is immersed under the liquid surface 11 b of the liquefied gas 11 .
  • the delivery line 20 is a path connected to the discharge part 12a of the delivery pump 12 and delivering the liquefied gas 11 from the liquefied gas tank 10 in a liquid state.
  • the liquefied gas 11 can be delivered from the liquefied gas tank 10 to the delivery line 20 .
  • the minimum flow line 23 is a path that branches off from the payout line 20 and can return the liquefied gas 11 to the liquefied gas tank 10 .
  • the liquefied gas 11 is circulated from the payout line 20 through the minimum flow line 23 when the flow rate is required to maintain the delivery pump 12 . Thereby, the minimum flow rate of the delivery pump 12 can be ensured.
  • the liquefied gas 11 may be discharged to the downstream side of the discharge line 20, or the downstream side may be shut off.
  • a mini-flow valve 24 is preferably installed in the minimum flow line 23 as a valve for changing the flow rate of the minimum flow or opening and closing the flow.
  • the miniflow valve 24 may be a control valve that adjusts the flow rate based on the indication of a pressure indicator controller 25 installed in the dispensing line 20 .
  • two or more delivery pumps 12 may be installed for the same liquefied gas tank 10 .
  • the dispensing line 20 in the illustrated example has a branch line portion 21 connected to the discharge portion 12 a of the delivery pump 12 and a trunk line portion 22 joined from the branch line portion 21 . This allows the payout line 20 to be shared by two or more delivery pumps 12 .
  • the minimum flow line 23 is shared by two or more delivery pumps 12 as well as the payout line 20 .
  • the flow rate of the minimum flow line 23 can be maintained by adjusting the opening degree of the mini flow valve 24 of the combined minimum flow line 23 according to the pressure value measured by the pressure indicator controller 25 . This eliminates the need for flow meters and regulating valves in the minimum flow line 23 for each delivery pump 12 .
  • the degree of opening of the miniflow valve 24 may become too large.
  • the flow rate may be excessively adjusted at a constant set value.
  • the pump discharge pressure of the delivery pump 12 measured by the pressure indicator controller 25 is controlled to be constant, the pump discharge pressure depends on the liquid level of the liquefied gas 11 stored in the liquefied gas tank 10 and the pump It can fluctuate under the influence of suction pressure.
  • the control system 30 of the embodiment controls the minimum flow in consideration of fluctuations in the internal state of the liquefied gas tank 10 . Specifically, from the density and liquid level of the liquefied gas 11 stored in the liquefied gas tank 10 and the gas phase pressure above the liquid level 11b of the liquefied gas 11 in the liquefied gas tank 10, the liquid level of the liquefied gas 11 is Calculate the pump suction pressure of the delivery pump 12 under 11b.
  • the pump suction pressure can be obtained.
  • the gas phase pressure of the liquefied gas 11 can be measured using a pressure gauge 13 installed on the liquid surface 11b of the liquefied gas 11, for example.
  • the weight per unit area (bottom area) of the liquefied gas 11 may be obtained, for example, by multiplying the height difference from the liquid surface 11b to the suction part 12b by the density and gravitational acceleration of the liquefied gas 11.
  • the density distribution may be integrated in the integration interval along the vertical direction. A more accurate value is obtained by considering the density distribution of the liquefied gas 11 .
  • the density and liquid level of the liquefied gas 11 can be measured, for example, by a density meter 14 and a level meter 15 using a measurement unit 16 immersed under the liquid level 11b of the liquefied gas 11. .
  • a single instrument capable of measuring the density, temperature and level of the liquefied gas 11 may be used. If the density distribution of the liquefied gas 11 is not considered, a density meter (not shown) immersed under the liquid surface 11b of the liquefied gas 11 may be used. If a density meter is not available, a manually entered density value may be used.
  • the outputs of pressure gauge 13, density gauge 14 and level gauge 15 are sent to control system 30 via signal paths 31, 32 and 33, respectively.
  • the signal paths 31, 32, 33 may be wired such as cables or wireless such as radio waves.
  • the control system 30 may be configured by a distributed control system (DCS).
  • Control system 30 may include, for example, an electronic circuit having a program.
  • Control system 30 may have storage if desired.
  • a storage device can be realized by using, for example, a semiconductor memory, a magnetic hard disk, or the like.
  • Deploying the control system 30 in the liquefied gas receiving facility 100 facilitates automation of control and integration of information.
  • the control system 30 can control the minimum flow of the delivery pump 12 using the pump suction pressure of the delivery pump 12 and the pump performance curve of the delivery pump 12 .
  • the pump performance curve is a curve representing the relationship between the flow rate (FLOWRATE) of the delivery pump 12 and the head (HEAD), as shown in FIG. 3, for example.
  • the pump performance curve C When the pump performance curve C is represented on a graph, it generally becomes a downward sloping curve, as shown in the figure, where the higher the flow rate, the lower the head.
  • the pump performance curve C can generally be expressed as a monotonically decreasing function.
  • the pump performance curve C When the pump performance curve C is stored in the control system 30, it may be a computable function, or may be a data structure showing flow values and corresponding head values.
  • the minimum flow rate F 0 required to maintain the delivery pump 12 can be set in advance from the specifications of the delivery pump 12, operating conditions, and the like.
  • the flow rate F1 in the dispensing line 20 is preferably greater than or equal to the minimum flow rate F0 . Since the pump performance curve C monotonically decreases with respect to the flow rate, the head H0 corresponding to the minimum flow rate is preferably equal to or greater than the head H1 corresponding to the flow rate F1 described above. Thus, by utilizing the fact that the pump performance curve C represents the relationship between the flow rate and the head , the minimum flow can be better controlled.
  • the pump discharge pressure of the delivery pump 12 is obtained by adding the "pump suction pressure” to the “pressure converted to the head", and furthermore, the "pressure loss in the piping” from the delivery pump 12 to the payout line 20 and the “height difference” are converted. It can be obtained by subtracting the pressure As for the "pressure loss in the piping", it is preferable to consider the pressure loss in the piping from the suction portion 12b of the delivery pump 12 to the pressure indicator controller 25 of the delivery line 20. Moreover, it is preferable to consider the difference in height from the suction portion 12b of the delivery pump 12 to the pressure indicator controller 25 of the dispensing line 20 for the "pressure obtained by converting the difference in height".
  • control system 30 is able to estimate the pump discharge pressure at the minimum flow F 0 based on the head H 0 corresponding to the minimum flow F 0 required to maintain the delivery pump 12 in the pump performance curve C. . By comparing the estimated pump discharge pressure to the actual pump discharge pressure measured in the payout line 20, the minimum flow can be controlled.
  • control system 30 controls miniflow valve 24 to increase the flow in minimum flow line 23 . Thereby, it is possible to suppress the shortage of the minimum flow. Additionally, control system 30 may decrease the flow rate in minimum flow line 23 if the measured pump discharge pressure is lower than the estimated pump discharge pressure. This can prevent the minimum flow from becoming excessive.
  • the measured value of the pump discharge pressure in the dispensing line 20 can be measured using the pressure indicating controller 25. Control is facilitated by comparing the measured pump discharge pressure to the estimated pump discharge pressure to control the minimum flow.
  • the corresponding head H 0 was obtained from the known minimum flow rate F 0 , but it is also possible to estimate the flow rate from the known head, conversely.
  • the control system 30 can use the actual pump discharge pressure measured in the payout line 20 , the pump suction pressure, and the pump performance curve C to determine an estimated flow rate in the payout line 20 .
  • the "pump suction pressure” is subtracted from the pump discharge pressure of the delivery pump 12, and the "pressure loss in the piping” and the “pressure obtained by converting the height difference” from the delivery pump 12 to the dispensing line 20 are calculated.
  • the pressure obtained by converting the lift H1 described above can be obtained.
  • an estimated flow rate is obtained as the flow rate F1 corresponding to the head H1 described above.
  • control system 30 controls the miniflow valve 24 to increase the flow rate in the minimum flow line 23 . Thereby, it is possible to suppress the shortage of the minimum flow. Additionally, control system 30 may decrease the flow rate in minimum flow line 23 if estimated flow rate F1 is greater than minimum flow rate F0. This can prevent the minimum flow from becoming excessive. Controlling the minimum flow by comparing the minimum flow rate F 0 to the estimated flow rate F 1 facilitates control.
  • the control method using the pump performance curve C described above suppresses an excessive flow rate in the minimum flow line 23, it is preferably applied when there is a high possibility that the actual flow rate is equal to or higher than the minimum flow rate F0 .
  • the pump discharge pressure of the delivery pump 12 is measured using the control described above, and the pump delivery pressure at the minimum flow rate F0 is estimated. It is also possible to control the minimum flow by whether it is higher than the value.
  • the minimum flow line 23 is shared by two or more delivery pumps 12 as well as the payout line 20 . It is not limited. The control method described above can also be applied when the payout line 20 or the minimum flow line 23 is installed one-to-one for each delivery pump 12 .
  • the flow rate is small, so the liquefied gas 11 may be flowed through the minimum flow line 23 through the mini-flow valve 24 for a predetermined time after the start-up of the delivery pump 12. good.
  • the flow rate of the minimum flow line 23 may become excessive within a predetermined period of time, but since the period of time is limited, the amount that is wasted is relatively small.
  • control since only the time from activation is used as a control factor, control becomes easier.
  • the delivery pump 12 in operation when simultaneously operating two or more delivery pumps 12 installed in the same liquefied gas tank 10, the delivery pump 12 in operation may be considered.
  • the control system 30 confirms that no other delivery pumps 12 are operating in the same liquefied gas tank 10
  • the first delivery pump 12 A liquefied gas may be flowed through the minimum flow line 23 through the miniflow valve 24 at a predetermined time after startup.
  • the control system 30 can confirm the number and number of the delivery pumps 12 in operation based on the operating status of the delivery pumps 12 and the activation status of the motors and the like. This allows control system 30 to determine whether other delivery pumps 12 are operating.
  • a miniflow valve 24 installed in the minimum flow line 23 has a capacity coefficient.
  • the definition of capacity factor varies by vendor of the miniflow valve 24, but may be, for example, a Cv value or a Kv value.
  • the capacity coefficient is a constant indicating that there is a specific relationship between the flow rate Q, the specific gravity G of the fluid, and the differential pressure ⁇ P.
  • the control system 30 can calculate the flow rate at the miniflow valve 24 from the pressure value of the pressure indicating controller 25 and the capacity coefficient of the miniflow valve 24 . Thereby, the control system 30 can determine whether or not the minimum flow is maintained.
  • Control system 30 sends or receives signals directly or indirectly to pressure indicating controller 25 and miniflow valve 24 via signal paths 34,35.
  • the signal paths 34 and 35 may be wired such as cables or wireless such as radio waves.
  • control system 30 can control to increase the flow rate in the miniflow valve 24 when the calculated value of the flow rate in the miniflow valve 24 calculated using the capacity coefficient is insufficient to maintain the minimum flow. Thereby, the minimum flow can be maintained more reliably.
  • the control method of the embodiment basically uses the control method using the pump performance curve C described above. Immediately after starting the delivery pump 12, the above-described (1) control method using the pump performance curve C, (2) control method for ensuring a constant flow rate at a predetermined time immediately after starting, and (3) the miniflow valve 24 By using one or more of the control methods using the capacity coefficient of , it is possible to more reliably maintain the minimum flow.
  • the flow rate at the miniflow valve 24 is also the sum of the flow rates of the two or more delivery pumps 12. value. Therefore, in the control method using the capacity coefficient of the miniflow valve 24, when only one delivery pump 12 is in operation, the flow rate calculated using the capacity coefficient is the same as the flow rate by the delivery pump 12 in operation. can be regarded as When two or more delivery pumps 12 are in operation, the flow rate calculated using the capacity factor is the sum of the flow rates of the two or more delivery pumps 12 . Therefore, the control system 30 may calculate the flow rate per pump according to the number of the pumps 12 in operation and use it for control.
  • the miniflow valve 24 is automatically closed.
  • Control method when additionally starting the delivery pump When starting one of the two or more delivery pumps 12 provided in the same liquefied gas tank 10, the control system 30 confirms that the delivery pump 12 different from the delivery pump 12 to be additionally started is being operated. When it does, a different control than the initial delivery pump 12 activation may be used.
  • the control system calculates the total flow rate downstream of the payout line 20, and determines whether or not this total value is sufficient to maintain the minimum flow of the newly started delivery pump 12 and the delivery pump 12 in operation. It is preferable to determine whether
  • FIG. 1 downstream of the payout line 20, a payout pipe 41 for supplying the gas in a state of being vaporized by the vaporizer 45 from the liquefied gas 11 to the gas supply unit 46, and a payout pipe 41 for supplying the liquefied gas 11 for the cold insulation circulation 54
  • a pipe 51 is shown downstream of the payout line 20
  • FIG. 2 also shows a payout pipe 61 for supplying the liquefied gas 11 for domestic ship shipment 64 and a payout pipe 71 for supplying the liquefied gas 11 for lorry shipment 74 .
  • a secondary pump 42 may be provided in the delivery pipe 41 when the pressure of the delivery pump 12 serving as the primary pump is insufficient to transfer the liquefied gas 11 .
  • the gas supply unit 46 supplies LNG to power plants, city gas production plants, and the like.
  • Flowmeters 43, 52, 62, 72 and valves 44, 53, 63, 73 are installed in the respective payout pipes 41, 51, 61, 71. These flow meters 43 , 52 , 62 , 72 are transmitted to control system 30 via signal path 36 .
  • the signal path 36 may be wired such as a cable or wireless such as radio waves.
  • the supply destinations of the delivery pipes 41, 51, 61, and 71 shown in FIGS. 1 and 2 are schematic examples, and the number, combination, and the like can be changed as appropriate. It can also be applied to supply destinations other than those exemplified, such as railway transportation.
  • the control system 30 will continue to operate the miniflow valve 24 even if the miniflow valve 24 remains closed. , it can be determined that there is no problem with additional start-up. Further, according to the control method immediately after starting the delivery pump 12 described above, the liquefied gas 11 may be controlled to flow through the minimum flow line 23 through the mini flow valve 24 at a predetermined time after the additional start of the delivery pump 12. .
  • the flow rate of the delivery pump 12 in operation is equal to the minimum flow of the delivery pump 12 in operation.
  • the liquefied gas receiving facility and control method of the present invention are not particularly limited, but can be used for LNG receiving bases, LPG receiving bases, storage facilities, and the like.
  • Pressure indicator controller 30 ... Control system, 31 32, 33, 34, 35, 36... signal path, 41, 51, 61, 71... discharge pipe, 42... secondary pump, 43, 52, 62, 72... flow meter, 44, 53, 63, 73... valve, 45...Vaporizer, 46...Gas supply unit, 54...Refrigerant circulation, 64...Domestic ship shipment, 74...Lorry shipment, 100...Liquefied gas receiving facility.

Abstract

According to the present invention, a liquefied gas receiving facility comprises a liquefied gas tank that stores a liquefied gas, a withdrawal line that withdraws the liquefied gas in a liquid state from the liquefied gas tank, a delivery pump that delivers the liquefied gas from the liquefied gas tank to the withdrawal line, and a minimum flow line that branches off from the withdrawal line and is capable of returning the liquefied gas to the liquefied gas tank, wherein: a pump suction pressure of the delivery pump below the liquid level of the liquefied gas is calculated from the density and liquid level of the liquefied gas stored in the liquefied gas tank, and a gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank; and a minimum flow of the delivery pump is controlled using the pump suction pressure, and a pump performance curve of the delivery pump.

Description

液化ガス受入設備およびその制御方法Liquefied gas receiving facility and its control method
　本発明は、液化ガスを受け入れて液化ガスタンクに貯蔵し、当該液化ガスを払出しラインから送出する液化ガス受入設備およびその制御方法に関する。 The present invention relates to a liquefied gas receiving facility that receives liquefied gas, stores it in a liquefied gas tank, and delivers the liquefied gas from a delivery line, and a control method thereof.
　液化天然ガス（LNG：Liquefied Natural Gas）、液化石油ガス（LPG：Liquefied Petroleum Gas）等の液化ガスは、気体の状態に比べて体積が小さいため、液体の状態で貯蔵および輸送に利用されている。流体を輸送するポンプでは、過少な流量における過熱、振動などを防止するため、ミニマムフローが設定されている。例えば特許文献１には、高圧ポンプユニットを用いた液化ガスの供給ラインからミニマムフローラインを分岐して、高圧ポンプユニットの持続的な作動を可能にすることが記載されている。 Liquefied natural gas (LNG: Liquefied Natural Gas), liquefied petroleum gas (LPG: Liquefied Petroleum Gas), and other liquefied gases are used in the liquid state for storage and transportation because their volume is smaller than that in the gaseous state. . In pumps that transport fluids, a minimum flow is set in order to prevent overheating, vibration, etc. due to an insufficient flow rate. For example, Patent Literature 1 describes branching a minimum flow line from a liquefied gas supply line using a high-pressure pump unit to enable continuous operation of the high-pressure pump unit.
　また、特許文献２には、ガス供給システムに使用される非バランス式減圧弁において、二次側の流量および二次側の圧力の測定値から、一次側の圧力を推定することが記載されている。 Further, Patent Document 2 describes estimating the primary side pressure from the measured value of the secondary side flow rate and the secondary side pressure in an unbalanced pressure reducing valve used in a gas supply system. there is
日本国特許第６８７６８２６号公報Japanese Patent No. 6876826 日本国特開２０２１－６００４４号公報Japanese Patent Application Laid-Open No. 2021-60044
　ＬＮＧ等の貯蔵タンクでは、貯蔵タンクの頂部に突出したポンプバレルにポンプを収容し、払出しラインの配管等を貯蔵タンクの頂部に配置する場合がある。さらにバルブ、流量計、圧力計等の機器も貯蔵タンクの頂部に設置される場合がある。しかし、貯蔵タンクの頂部に設置される設備の重量が増大すると、操作架台やタンク自体が大型になり、耐荷重を増強する必要が生じて、設置コストが増大するおそれがある。 　In storage tanks such as LNG, there are cases where the pump is housed in a pump barrel protruding from the top of the storage tank, and the payout line piping, etc. are arranged at the top of the storage tank. Additionally, equipment such as valves, flow meters, pressure gauges, etc. may also be installed at the top of the storage tank. However, if the weight of the equipment installed on the top of the storage tank increases, the operation platform and the tank itself will become large, and the load capacity will need to be increased, which may increase the installation cost.
　貯蔵タンクには、ポンプの輸送量を増加可能にするため、あるいはポンプの不具合に対する予備のため、複数のポンプを設置する場合がある。ポンプごとにミニマムフローラインを設けると、ミニマムフローラインに付属する設備や機器もポンプごとに設置する必要が生じる。 　In some cases, multiple pumps may be installed in the storage tank in order to increase the transport capacity of the pump or as a backup against pump failure. If a minimum flow line is provided for each pump, it will be necessary to install facilities and equipment attached to the minimum flow line for each pump.
　ポンプの設定上の最小流量よりも多い流量をミニマムフローとして維持すれば、ミニマムフローの制御は容易になる。しかし、必要以上の流量を維持することにより、液化ガスの蒸発量の増加等による運転コストが増大するおそれがある。 By maintaining a flow rate higher than the minimum flow rate on the pump setting as the minimum flow, it becomes easier to control the minimum flow. However, maintaining a flow rate more than necessary may increase the operating cost due to, for example, an increase in the amount of evaporation of the liquefied gas.
　本発明の課題は、ミニマムフローラインの設備を簡素化して、コストを低減することが可能な液化ガス受入設備およびその制御方法を提供することである。 An object of the present invention is to provide a liquefied gas receiving facility and a control method thereof that can simplify the minimum flow line facility and reduce costs.
　本発明の第１の態様は、液化ガスを貯蔵する液化ガスタンクと、前記液化ガスタンクから液化ガスを液体の状態で払い出す払出しラインと、前記液化ガスタンクから液化ガスを前記払出しラインに送出する送出ポンプと、前記払出しラインから分岐して、液化ガスを前記液化ガスタンクに戻すことが可能なミニマムフローラインと、制御システムと、を備える液化ガス受入設備であって、前記制御システムは、前記液化ガスタンクに貯蔵されている液化ガスの密度および液面レベルと、前記液化ガスタンク内における前記液化ガスの液面上の気相圧力とから、前記液化ガスの液面下における前記送出ポンプのポンプ吸込圧力を算出すると共に、前記ポンプ吸込圧力と、前記送出ポンプのポンプ性能曲線とを用いて、前記送出ポンプのミニマムフローを制御することを特徴とする液化ガス受入設備である。 A first aspect of the present invention includes a liquefied gas tank for storing liquefied gas, a delivery line for delivering the liquefied gas from the liquefied gas tank in a liquid state, and a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line. and a minimum flow line branching from the payout line and capable of returning the liquefied gas to the liquefied gas tank; The pump suction pressure of the delivery pump below the liquid level of the liquefied gas is calculated from the density and liquid level of the stored liquefied gas and the gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank. Further, the liquefied gas receiving facility is characterized in that the minimum flow of the delivery pump is controlled using the pump suction pressure and the pump performance curve of the delivery pump.
　本発明の第２の態様は、第１の態様において、前記制御システムは、前記ポンプ性能曲線における、前記送出ポンプの維持に必要な最小流量に対応する揚程を換算した圧力と、前記ポンプ吸込圧力から、前記最小流量におけるポンプ吐出圧力を推定し、前記ポンプ吐出圧力の推定値を、前記払出しラインにおいて測定したポンプ吐出圧力の実測値と比較して、前記ポンプ吐出圧力の実測値が、前記ポンプ吐出圧力の推定値より高い場合は、前記ミニマムフローラインの流量を増加させ、前記ポンプ吐出圧力の実測値が、前記ポンプ吐出圧力の推定値より低い場合は、前記ミニマムフローラインの流量を減少させることを特徴とする。 According to a second aspect of the present invention, in the first aspect, the control system includes, in the pump performance curve, a pressure converted to a head corresponding to a minimum flow rate required to maintain the delivery pump, and the pump suction pressure Estimate the pump discharge pressure at the minimum flow rate, compare the estimated value of the pump discharge pressure with the measured value of the pump discharge pressure measured in the payout line, and compare the measured value of the pump discharge pressure with the measured value of the pump discharge pressure When the discharge pressure is higher than the estimated value, the flow rate of the minimum flow line is increased, and when the measured value of the pump discharge pressure is lower than the estimated value of the pump discharge pressure, the flow rate of the minimum flow line is decreased. It is characterized by
　本発明の第３の態様は、第１の態様において、前記制御システムは、前記払出しラインにおいて測定したポンプ吐出圧力の実測値と、前記ポンプ吸込圧力と、前記ポンプ性能曲線とを用いて、前記払出しラインにおける推定流量を求め、前記推定流量が、前記送出ポンプの維持に必要な最小流量より少ない場合は、前記ミニマムフローラインの流量を増加させ、前記推定流量が、前記送出ポンプの維持に必要な最小流量より多い場合は、前記ミニマムフローラインの流量を減少させることを特徴とする。 According to a third aspect of the present invention, in the first aspect, the control system uses the actual value of the pump discharge pressure measured in the payout line, the pump suction pressure, and the pump performance curve to determine the determining an estimated flow rate in a payout line, and if the estimated flow rate is less than the minimum flow rate required to maintain the delivery pump, increasing the flow rate in the minimum flow line, wherein the estimated flow rate is less than the estimated flow rate required to maintain the delivery pump; is more than the minimum flow rate, the flow rate of the minimum flow line is reduced.
　本発明の第４の態様は、第１～第３の態様のいずれか１つにおいて、前記液化ガス受入設備は、同一の液化ガスタンクに対し、２以上の送出ポンプと、前記２以上の送出ポンプに共用される払出しラインと、を備え、前記ミニマムフローラインには、ミニフロー弁が配置され、前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていないことを確認したときは、最初の送出ポンプの起動から所定の時間において、前記ミニフロー弁を通じて前記ミニマムフローラインに液化ガスを流すことを特徴とする。 According to a fourth aspect of the present invention, in any one of the first to third aspects, the liquefied gas receiving equipment includes two or more delivery pumps and the two or more delivery pumps for the same liquefied gas tank. and a payout line shared with the same liquefied gas tank, wherein the minimum flow line includes a miniflow valve disposed therein, and the control system, when activating any of the two or more delivery pumps, actuates the other in the same liquefied gas tank. When it is confirmed that the delivery pump is not in operation, the liquefied gas is allowed to flow through the mini-flow valve to the minimum flow line for a predetermined time after the first delivery pump is activated.
　本発明の第５の態様は、第４の態様において、前記払出しラインには、前記液化ガスの圧力指示調節計が配置され、前記制御システムは、前記圧力指示調節計の圧力値と、前記ミニフロー弁の容量係数とから、前記ミニフロー弁における流量を計算し、前記ミニマムフローが維持されているか否かを判別することを特徴とする。 According to a fifth aspect of the present invention, in the fourth aspect, a pressure indicator controller for the liquefied gas is arranged in the delivery line, and the control system controls the pressure value of the pressure indicator controller and the mini The flow rate in the miniflow valve is calculated from the capacity coefficient of the flow valve, and it is determined whether or not the minimum flow is maintained.
　本発明の第６の態様は、第５の態様において、前記制御システムは、前記ミニフロー弁における流量の計算値が前記ミニマムフローの維持に不足するとき、前記ミニフロー弁における流量を増加させることを特徴とする。 According to a sixth aspect of the present invention, in the fifth aspect, the control system increases the flow rate in the miniflow valve when the calculated value of the flow rate in the miniflow valve is insufficient to maintain the minimum flow. characterized by
　本発明の第７の態様は、第４～第６の態様のいずれか１つにおいて、前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていることを確認したときは、前記払出しラインの下流における流量の合計値を算出し、この合計値が、新たに起動する送出ポンプおよび運転中の送出ポンプのミニマムフローの維持に十分か否かを判別することを特徴とする。 In a seventh aspect of the present invention, in any one of the fourth to sixth aspects, the control system, when activating any one of the two or more delivery pumps, controls other delivery pumps in the same liquefied gas tank. When it is confirmed that the pump is running, the total flow rate downstream of the payout line is calculated, and this total value is used to maintain minimum flow for the newly started and running pumps. It is characterized by determining whether it is sufficient or not.
　本発明の第８の態様は、第４～第７の態様のいずれか１つにおいて、前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていることを確認したときは、新たに起動する送出ポンプの起動から所定の時間において、前記ミニフロー弁を通じて前記ミニマムフローラインに液化ガスを流すことを特徴とする。 In an eighth aspect of the present invention, in any one of the fourth to seventh aspects, the control system, when activating any one of the two or more delivery pumps, controls other delivery pumps in the same liquefied gas tank. When it is confirmed that the pump is operating, the liquefied gas is allowed to flow through the mini-flow valve to the minimum flow line for a predetermined time after the start of the newly started delivery pump.
　本発明の第９の態様は、液化ガスを貯蔵する液化ガスタンクと、前記液化ガスタンクから液化ガスを液体の状態で払い出す払出しラインと、前記液化ガスタンクから液化ガスを前記払出しラインに送出する送出ポンプと、前記払出しラインから分岐して、液化ガスを前記液化ガスタンクに戻すことが可能なミニマムフローラインと、を備える液化ガス受入設備の制御方法であって、前記液化ガスタンクに貯蔵されている液化ガスの密度および液面レベルと、前記液化ガスタンク内における前記液化ガスの液面上の気相圧力とから、前記液化ガスの液面下における前記送出ポンプのポンプ吸込圧力を算出すると共に、前記ポンプ吸込圧力と、前記送出ポンプのポンプ性能曲線とを用いて、前記送出ポンプのミニマムフローを制御することを特徴とする液化ガス受入設備の制御方法である。 A ninth aspect of the present invention is a liquefied gas tank for storing liquefied gas, a delivery line for delivering the liquefied gas from the liquefied gas tank in a liquid state, and a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line. and a minimum flow line branching from the delivery line and capable of returning the liquefied gas to the liquefied gas tank, wherein the liquefied gas stored in the liquefied gas tank. and the gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank, calculate the pump suction pressure of the delivery pump below the liquid level of the liquefied gas, and A control method for a liquefied gas receiving facility, characterized in that the minimum flow of the delivery pump is controlled using the pressure and the pump performance curve of the delivery pump.
　第１の態様によれば、払出しラインに流量計を設置しなくても、あるいは流量計がポンプごとに付属されなくても、送出ポンプのミニマムフローを制御することが可能になる。このため、ミニマムフローラインの設備を簡素化して、コストを低減することができる。また、液化ガスの受け入れ、払い出しによる液面や液密度の変動に伴い、最適なミニマムフロー値を設定することで、運転コストを下げることができる。 According to the first aspect, it is possible to control the minimum flow of the delivery pump without installing a flow meter in the dispensing line or attaching a flow meter to each pump. Therefore, the equipment of the minimum flow line can be simplified and the cost can be reduced. In addition, operating costs can be reduced by setting the optimum minimum flow value according to fluctuations in the liquid level and liquid density caused by receiving and discharging liquefied gas.
　第２の態様によれば、払出しラインにおけるポンプ吐出圧力の実測値を、ポンプ吐出圧力の推定値と比較して、ミニマムフローを制御するため、制御が最適化される。 According to the second aspect, the control is optimized to control the minimum flow by comparing the measured value of the pump discharge pressure in the payout line with the estimated value of the pump discharge pressure.
　第３の態様によれば、送出ポンプの維持に必要な最小流量を、払出しラインにおける推定流量と比較して、ミニマムフローを制御するため、制御が最適化される。 According to the third aspect, the control is optimized to control the minimum flow by comparing the minimum flow required to maintain the delivery pump to the estimated flow in the payout line.
　第４の態様によれば、最初の送出ポンプの起動から所定の時間は流量が少ないことを想定してミニマムフローを確保するため、制御が容易になる。起動から所定の時間を経過した後は、状況に応じて、ミニマムフローラインにおける流量を増減して制御することにより、必要以上の流量が流れることを抑制でき、運転コストを低減することができる。 According to the fourth aspect, the minimum flow is ensured on the assumption that the flow rate is low for a predetermined period of time after the first start-up of the delivery pump, which facilitates control. After a predetermined time has passed since the startup, the flow rate in the minimum flow line can be increased or decreased depending on the situation to control the flow rate more than necessary, and the operating cost can be reduced.
　第５の態様によれば、ミニフロー弁における流量を計算することにより、ミニマムフローをより確実に維持することができる。 According to the fifth aspect, the minimum flow can be maintained more reliably by calculating the flow rate in the miniflow valve.
　第６の態様によれば、ミニフロー弁における流量の計算値に基づいて、流量を増加させることにより、ミニマムフローをより確実に維持することができる。 According to the sixth aspect, the minimum flow can be more reliably maintained by increasing the flow rate based on the calculated value of the flow rate in the miniflow valve.
　第７の態様によれば、２台目以降となる送出ポンプの起動に際して、運転中の送出ポンプの流量が、運転中の送出ポンプのミニマムフローと２台目以降に起動する送出ポンプのミニマムフローの合計値より多いことを下流の流量計で確認することにより、２台目以降に起動する送出ポンプのミニマムフローをより確実に維持することができる。 According to the seventh aspect, when the second and subsequent delivery pumps are activated, the flow rates of the delivery pumps in operation are the minimum flow of the delivery pumps in operation and the minimum flow of the delivery pumps to be activated after the second delivery pump. By confirming with a downstream flow meter that the total value of is larger than the total value of , it is possible to more reliably maintain the minimum flow of the second and subsequent delivery pumps.
　第８の態様によれば、２台目以降となる送出ポンプの起動においても、送出ポンプの起動から所定の時間は流量が少ないことを想定してミニマムフローを確保するため、制御が容易になる。起動から所定の時間を経過した後は、状況に応じて、ミニマムフローラインにおける流量を増減して制御することにより、必要以上の流量が流れることを抑制でき、運転コストを低減することができる。 According to the eighth aspect, even when the second and subsequent delivery pumps are started, the minimum flow is ensured on the assumption that the flow rate is low for a predetermined time after the delivery pump is started, so control becomes easy. . After a predetermined time has passed since the startup, the flow rate in the minimum flow line can be increased or decreased depending on the situation to control the flow rate more than necessary, and the operating cost can be reduced.
　第９の態様によれば、払出しラインに流量計を設置しなくても、あるいは流量計がポンプごとに付属されなくても、送出ポンプのミニマムフローを制御することが可能になる。このため、ミニマムフローラインの設備を簡素化して、コストを低減することができる。また、液化ガスの受け入れ、払い出しによる液面や液密度の変動に伴い、最適なミニマムフロー値を設定することで、運転コストを下げることができる。 According to the ninth aspect, it is possible to control the minimum flow of the delivery pump without installing a flow meter in the dispensing line or attaching a flow meter to each pump. Therefore, the equipment of the minimum flow line can be simplified and the cost can be reduced. In addition, operating costs can be reduced by setting the optimum minimum flow value according to fluctuations in the liquid level and liquid density caused by receiving and discharging liquefied gas.
液化ガス受入設備の第１実施形態を示す概略図である。1 is a schematic diagram showing a first embodiment of a liquefied gas receiving facility; FIG. 液化ガス受入設備の第２実施形態を示す概略図である。FIG. 4 is a schematic diagram showing a second embodiment of a liquefied gas receiving facility; ポンプ性能曲線の一例を示す説明図である。It is an explanatory view showing an example of a pump performance curve.
　以下、好適な実施形態に基づいて、本発明を説明する。 The present invention will be described below based on preferred embodiments.
＜液化ガス受入設備＞
　図１および図２に、液化ガス受入設備１００の実施形態を示す。これらの実施形態は、液化ガス１１を払い出す下流側の例示が異なる以外は同様の構成を備えている。このため、図１および図２に共通する構成は、実施形態を区別せずに説明する場合がある。 <Liquefied gas receiving facility>
An embodiment of a liquefied gas receiving facility 100 is shown in FIGS. These embodiments are provided with the same configuration except for the illustration of the downstream side where the liquefied gas 11 is paid out. Therefore, the configuration common to FIGS. 1 and 2 may be described without distinguishing between the embodiments.
　液化ガス受入設備１００は、液化ガス１１を貯蔵する液化ガスタンク１０と、液化ガス１１を送出する送出ポンプ１２と、液化ガス１１の払出しライン２０と、ミニマムフローライン２３と、制御システム３０と、を備える。 The liquefied gas receiving facility 100 includes a liquefied gas tank 10 that stores the liquefied gas 11, a delivery pump 12 that delivers the liquefied gas 11, a delivery line 20 for the liquefied gas 11, a minimum flow line 23, and a control system 30. Prepare.
　液化ガス１１は、常温常圧では気体である物質を、圧縮、冷却等により液化した流体である。液化ガス１１となり得る物質としては、特に限定されないが、有機物でも無機物でもよく、単一物質でも混合物でもよい。具体例としては、天然ガス、石油ガス、合成ガス、低級（Ｃ１～Ｃ４程度）の炭素水素、水素（Ｈ２）、アンモニア（ＮＨ３）、酸素（Ｏ２）、窒素（Ｎ２）、空気等が挙げられる。 The liquefied gas 11 is a fluid obtained by liquefying a substance that is gas at normal temperature and normal pressure by compression, cooling, or the like. A substance that can be the liquefied gas 11 is not particularly limited, but may be an organic substance or an inorganic substance, and may be a single substance or a mixture. Specific examples include natural gas, petroleum gas, synthetic gas, low-grade (about C1 to C4) hydrocarbons, hydrogen (H 2 ), ammonia (NH 3 ), oxygen (O 2 ), nitrogen (N 2 ), and air. etc.
　液化ガスタンク１０は、液化ガス１１を貯蔵する容器である。液化ガスタンク１０は、地上式でもよく、地下式でもよく、半地下式でもよい。液化ガスタンク１０内の液化ガス１１は、液化ガスタンク１０の頂部１０ａ側に気相部１１ａを含んでもよい。特に図示しないが、液化ガスタンク１０には、タンカー等から液化ガス１１を受け入れるための受入ラインが設置される。 The liquefied gas tank 10 is a container that stores the liquefied gas 11. The liquefied gas tank 10 may be an above-ground type, an underground type, or a semi-underground type. The liquefied gas 11 in the liquefied gas tank 10 may include a gas phase portion 11a on the top portion 10a side of the liquefied gas tank 10 . Although not shown, the liquefied gas tank 10 is provided with a receiving line for receiving the liquefied gas 11 from a tanker or the like.
　送出ポンプ１２は、液化ガスタンク１０の頂部１０ａから底部１０ｂ側に向けて設置されている。送出ポンプ１２の吐出部１２ａは、液化ガスタンク１０の頂部１０ａ上に設置されている。送出ポンプ１２の吸込部１２ｂは、液化ガス１１の液面１１ｂ下に浸漬されている。 The delivery pump 12 is installed from the top 10a of the liquefied gas tank 10 toward the bottom 10b. A discharge portion 12 a of the delivery pump 12 is installed on the top portion 10 a of the liquefied gas tank 10 . A suction portion 12 b of the delivery pump 12 is immersed under the liquid surface 11 b of the liquefied gas 11 .
　払出しライン２０は、送出ポンプ１２の吐出部１２ａに接続されて、液化ガスタンク１０から液化ガス１１を液体の状態で払い出す経路である。送出ポンプ１２を運転することにより、液化ガスタンク１０から液化ガス１１を払出しライン２０に送出することができる。 The delivery line 20 is a path connected to the discharge part 12a of the delivery pump 12 and delivering the liquefied gas 11 from the liquefied gas tank 10 in a liquid state. By operating the delivery pump 12 , the liquefied gas 11 can be delivered from the liquefied gas tank 10 to the delivery line 20 .
　ミニマムフローライン２３は、払出しライン２０から分岐して、液化ガス１１を液化ガスタンク１０に戻すことが可能な経路である。送出ポンプ１２の維持に流量が必要な場合は、払出しライン２０からミニマムフローライン２３を通じて液化ガス１１を循環させる。これにより、送出ポンプ１２の最小流量を確保することができる。ミニマムフローライン２３に液化ガス１１を流しているとき、液化ガス１１が払出しライン２０の下流側に払い出されている場合もあれば、下流側が締め切られている場合もあり得る。 The minimum flow line 23 is a path that branches off from the payout line 20 and can return the liquefied gas 11 to the liquefied gas tank 10 . The liquefied gas 11 is circulated from the payout line 20 through the minimum flow line 23 when the flow rate is required to maintain the delivery pump 12 . Thereby, the minimum flow rate of the delivery pump 12 can be ensured. When the liquefied gas 11 is flowing through the minimum flow line 23, the liquefied gas 11 may be discharged to the downstream side of the discharge line 20, or the downstream side may be shut off.
　ミニマムフローライン２３には、ミニマムフローの流量を変更し、または流れを開閉するためのバルブとして、ミニフロー弁２４を設置することが好ましい。ミニフロー弁２４は、払出しライン２０に設置された圧力指示調節計２５の指示に基づいて流量を調節するコントロールバルブであってもよい。 A mini-flow valve 24 is preferably installed in the minimum flow line 23 as a valve for changing the flow rate of the minimum flow or opening and closing the flow. The miniflow valve 24 may be a control valve that adjusts the flow rate based on the indication of a pressure indicator controller 25 installed in the dispensing line 20 .
　特に限定されないが、同一の液化ガスタンク１０に対し、２以上の送出ポンプ１２が設置されていてもよい。この場合、送出ポンプ１２ごとに払出しライン２０を設けることも可能である。図示例の払出しライン２０は、送出ポンプ１２の吐出部１２ａに接続された支線部２１と、支線部２１から合流された幹線部２２とを有する。これにより、払出しライン２０を２以上の送出ポンプ１２に共用することができる。 Although not particularly limited, two or more delivery pumps 12 may be installed for the same liquefied gas tank 10 . In this case, it is also possible to provide a payout line 20 for each delivery pump 12 . The dispensing line 20 in the illustrated example has a branch line portion 21 connected to the discharge portion 12 a of the delivery pump 12 and a trunk line portion 22 joined from the branch line portion 21 . This allows the payout line 20 to be shared by two or more delivery pumps 12 .
　図示例の場合、払出しライン２０と同様に、ミニマムフローライン２３も２以上の送出ポンプ１２に共用されている。圧力指示調節計２５で測定した圧力値により、１つにまとめたミニマムフローライン２３のミニフロー弁２４の開度を調整することで、ミニマムフローライン２３の流量を維持することができる。これにより、各々の送出ポンプ１２に対するミニマムフローライン２３に必要な流量計や調整弁を省くことができる。 In the illustrated example, the minimum flow line 23 is shared by two or more delivery pumps 12 as well as the payout line 20 . The flow rate of the minimum flow line 23 can be maintained by adjusting the opening degree of the mini flow valve 24 of the combined minimum flow line 23 according to the pressure value measured by the pressure indicator controller 25 . This eliminates the need for flow meters and regulating valves in the minimum flow line 23 for each delivery pump 12 .
　しかしながら、あらかじめ決定した一定の設定値によりミニフロー弁２４の開度を調整すると、ミニフロー弁２４の開度が大きくなりすぎる場合がある。例えば、外部から液化ガスタンク１０への液化ガス１１の供給や送出ポンプ１２による払出しにより、液化ガスタンク１０の内部状態が変動すると、一定の設定値では流量が過大な調整となる場合がある。例えば、圧力指示調節計２５で測定される送出ポンプ１２のポンプ吐出圧力が一定となるように制御する場合、ポンプ吐出圧力は、液化ガスタンク１０に貯蔵されている液化ガス１１の液面レベルおよびポンプ吸込圧力の影響を受けて変動し得る。同じ流量でも、液面が低いとポンプ吐出圧力が低下し、液面が高いとポンプ吐出圧力が上昇する。このため、液面が高いときに最小流量が確保される設定値では、液面が低いときにミニマムフローが不足する。これとは逆に、液面が低いときに最小流量が確保される設定値では、液面が高いときにミニマムフローが過剰になる。常にミニマムフローが不足しないように制御するには、液面が低いときの条件で設定値を導入する必要があるが、液面が高いときには、必要な最小流量よりも多い流量が設定される結果となる。過剰な流量により、液化ガスタンク１０内のボイルオフガス（ＢＯＧ）発生量が増え、運転費が増えるおそれがある。このため、より適切にミニマムフローを制御することにより、実際に必要なミニマムフローの流量を、一定の設定値を用いて制御するよりも、少なく済ませることができる。 However, if the degree of opening of the miniflow valve 24 is adjusted with a predetermined set value, the degree of opening of the miniflow valve 24 may become too large. For example, if the internal state of the liquefied gas tank 10 fluctuates due to external supply of the liquefied gas 11 to the liquefied gas tank 10 or discharge by the delivery pump 12, the flow rate may be excessively adjusted at a constant set value. For example, when the pump discharge pressure of the delivery pump 12 measured by the pressure indicator controller 25 is controlled to be constant, the pump discharge pressure depends on the liquid level of the liquefied gas 11 stored in the liquefied gas tank 10 and the pump It can fluctuate under the influence of suction pressure. Even if the flow rate is the same, if the liquid level is low, the pump discharge pressure will decrease, and if the liquid level is high, the pump discharge pressure will increase. Therefore, the set value that ensures the minimum flow rate when the liquid level is high results in insufficient minimum flow when the liquid level is low. Conversely, a setting that ensures a minimum flow rate when the liquid level is low results in excessive minimum flow when the liquid level is high. In order to control the minimum flow so that it does not run short at all times, it is necessary to introduce the set value under conditions when the liquid level is low. becomes. An excessive flow rate may increase the amount of boil-off gas (BOG) generated in the liquefied gas tank 10 and increase operating costs. Therefore, by controlling the minimum flow more appropriately, the actually required minimum flow rate can be reduced compared to controlling using a constant set value.
＜ポンプ性能曲線を用いた制御方法＞
　実施形態の制御システム３０は、液化ガスタンク１０の内部状態の変動を考慮して、ミニマムフローを制御する。具体的には、液化ガスタンク１０に貯蔵されている液化ガス１１の密度および液面レベルと、液化ガスタンク１０内における液化ガス１１の液面１１ｂ上の気相圧力とから、液化ガス１１の液面１１ｂ下における送出ポンプ１２のポンプ吸込圧力を算出する。 <Control method using pump performance curve>
The control system 30 of the embodiment controls the minimum flow in consideration of fluctuations in the internal state of the liquefied gas tank 10 . Specifically, from the density and liquid level of the liquefied gas 11 stored in the liquefied gas tank 10 and the gas phase pressure above the liquid level 11b of the liquefied gas 11 in the liquefied gas tank 10, the liquid level of the liquefied gas 11 is Calculate the pump suction pressure of the delivery pump 12 under 11b.
　送出ポンプ１２の吸込部１２ｂが液面１１ｂ下にある場合は、吸込部１２ｂにおけるポンプ吸込圧力を直接測定することが困難である。そこで、液化ガス１１の液面１１ｂ上の気相圧力に、液化ガス１１の重量に起因する圧力を加えることで、ポンプ吸込圧力を求めることができる。液化ガス１１の気相圧力は、例えば、液化ガス１１の液面１１ｂ上に設置されている圧力計１３を用いて測定することができる。 When the suction portion 12b of the delivery pump 12 is below the liquid surface 11b, it is difficult to directly measure the pump suction pressure at the suction portion 12b. Therefore, by adding the pressure due to the weight of the liquefied gas 11 to the gas phase pressure above the liquid surface 11b of the liquefied gas 11, the pump suction pressure can be obtained. The gas phase pressure of the liquefied gas 11 can be measured using a pressure gauge 13 installed on the liquid surface 11b of the liquefied gas 11, for example.
　液化ガス１１の単位面積（底面積）当たりの重量は、例えば、液面１１ｂから吸込部１２ｂまでの高低差に液化ガス１１の密度および重力加速度を乗じて求めてもよい。液化ガス１１が鉛直方向に密度分布を有するときは、鉛直方向に沿った積分区間において密度分布を積分してもよい。液化ガス１１の密度分布を考慮することにより、より正確な値が得られる。 The weight per unit area (bottom area) of the liquefied gas 11 may be obtained, for example, by multiplying the height difference from the liquid surface 11b to the suction part 12b by the density and gravitational acceleration of the liquefied gas 11. When the liquefied gas 11 has a density distribution in the vertical direction, the density distribution may be integrated in the integration interval along the vertical direction. A more accurate value is obtained by considering the density distribution of the liquefied gas 11 .
　具体的には、液化ガス１１の密度および液面レベルは、例えば、液化ガス１１の液面１１ｂ下に浸漬されている測定部１６を用いた密度計１４およびレベル計１５によって測定することができる。液化ガス１１の密度、温度、レベルを一台で計測することが可能な計器を使用してもよい。液化ガス１１の密度分布を考慮しない場合は、液化ガス１１の液面１１ｂ下に浸漬された密度計（図示せず）を用いてもよい。密度計がない場合は、手動で入力した密度の値を用いてもよい。 Specifically, the density and liquid level of the liquefied gas 11 can be measured, for example, by a density meter 14 and a level meter 15 using a measurement unit 16 immersed under the liquid level 11b of the liquefied gas 11. . A single instrument capable of measuring the density, temperature and level of the liquefied gas 11 may be used. If the density distribution of the liquefied gas 11 is not considered, a density meter (not shown) immersed under the liquid surface 11b of the liquefied gas 11 may be used. If a density meter is not available, a manually entered density value may be used.
　圧力計１３、密度計１４およびレベル計１５の出力は、それぞれ信号経路３１，３２，３３を介して制御システム３０に送信される。信号経路３１，３２，３３は、ケーブル等の有線でもよく、電波等の無線でもよい。 The outputs of pressure gauge 13, density gauge 14 and level gauge 15 are sent to control system 30 via signal paths 31, 32 and 33, respectively. The signal paths 31, 32, 33 may be wired such as cables or wireless such as radio waves.
　制御システム３０は、分散制御システム（DCS：Distributed Control System）によって構成されてもよい。制御システム３０が例えばプログラムを有する電子回路を含んでもよい。制御システム３０は、必要に応じて、記憶装置を持ってよい。記憶装置は、例えば、半導体メモリー、磁気ハードディスク等を用いて実現することができる。 The control system 30 may be configured by a distributed control system (DCS). Control system 30 may include, for example, an electronic circuit having a program. Control system 30 may have storage if desired. A storage device can be realized by using, for example, a semiconductor memory, a magnetic hard disk, or the like.
　液化ガス受入設備１００に制御システム３０を配備することにより、制御の自動化、情報の統合化が容易になる。実施形態の制御を実施する際、制御システム３０以外の判断主体が、情報を集約して制御を実施することも可能である。 Deploying the control system 30 in the liquefied gas receiving facility 100 facilitates automation of control and integration of information. When implementing the control of the embodiment, it is also possible for a decision subject other than the control system 30 to aggregate information and implement control.
　制御システム３０は、送出ポンプ１２のポンプ吸込圧力と、送出ポンプ１２のポンプ性能曲線とを用いて、送出ポンプ１２のミニマムフローを制御することができる。ポンプ性能曲線とは、例えば図３に示すように、送出ポンプ１２の流量（FLOWRATE）に対する揚程（HEAD）の関係を表す曲線である。 The control system 30 can control the minimum flow of the delivery pump 12 using the pump suction pressure of the delivery pump 12 and the pump performance curve of the delivery pump 12 . The pump performance curve is a curve representing the relationship between the flow rate (FLOWRATE) of the delivery pump 12 and the head (HEAD), as shown in FIG. 3, for example.
　ポンプ性能曲線Ｃをグラフに表すと、一般に図示のように、流量が多いほど揚程が低下する右肩下がりの曲線となる。ポンプ性能曲線Ｃは、おおむね、単調減少関数として表現することができる。ポンプ性能曲線Ｃを制御システム３０に格納するときには、演算可能な関数であってもよく、流量の値とこれに対応する揚程の値を示したデータ構造であってもよい。 When the pump performance curve C is represented on a graph, it generally becomes a downward sloping curve, as shown in the figure, where the higher the flow rate, the lower the head. The pump performance curve C can generally be expressed as a monotonically decreasing function. When the pump performance curve C is stored in the control system 30, it may be a computable function, or may be a data structure showing flow values and corresponding head values.
　送出ポンプ１２の維持に必要な最小流量Ｆ０は、送出ポンプ１２の仕様、運転条件等からあらかじめ設定することができる。払出しライン２０における流量Ｆ１は、最小流量Ｆ０以上であることが好ましい。ポンプ性能曲線Ｃが流量に対して単調減少となるため、最小流量に対応する揚程Ｈ０は、上述の流量Ｆ１に対応する揚程Ｈ１以上となることが好ましい。このように、ポンプ性能曲線Ｃが流量と揚程の関係を表していることを利用すれば、払出しライン２０における流量Ｆ１が実測値でなく、後述する推定流量Ｆ１であっても、ミニマムフローをより適切に制御することが可能になる。 The minimum flow rate F 0 required to maintain the delivery pump 12 can be set in advance from the specifications of the delivery pump 12, operating conditions, and the like. The flow rate F1 in the dispensing line 20 is preferably greater than or equal to the minimum flow rate F0 . Since the pump performance curve C monotonically decreases with respect to the flow rate, the head H0 corresponding to the minimum flow rate is preferably equal to or greater than the head H1 corresponding to the flow rate F1 described above. Thus, by utilizing the fact that the pump performance curve C represents the relationship between the flow rate and the head , the minimum flow can be better controlled.
　送出ポンプ１２のポンプ吐出圧力は、「ポンプ吸込圧力」に「揚程を換算した圧力」を加え、さらに、送出ポンプ１２から払出しライン２０までの「配管中の圧力損失」および「高低差を換算した圧力」を差し引くことで求めることができる。「配管中の圧力損失」は、送出ポンプ１２の吸込部１２ｂから払出しライン２０の圧力指示調節計２５までの配管中の圧力損失を考慮することが好ましい。また、「高低差を換算した圧力」は、送出ポンプ１２の吸込部１２ｂから払出しライン２０の圧力指示調節計２５までの高低差を考慮することが好ましい。 The pump discharge pressure of the delivery pump 12 is obtained by adding the "pump suction pressure" to the "pressure converted to the head", and furthermore, the "pressure loss in the piping" from the delivery pump 12 to the payout line 20 and the "height difference" are converted. It can be obtained by subtracting the pressure As for the "pressure loss in the piping", it is preferable to consider the pressure loss in the piping from the suction portion 12b of the delivery pump 12 to the pressure indicator controller 25 of the delivery line 20. Moreover, it is preferable to consider the difference in height from the suction portion 12b of the delivery pump 12 to the pressure indicator controller 25 of the dispensing line 20 for the "pressure obtained by converting the difference in height".
　したがって、制御システム３０は、ポンプ性能曲線Ｃにおける、送出ポンプ１２の維持に必要な最小流量Ｆ０に対応する揚程Ｈ０に基づき、最小流量Ｆ０におけるポンプ吐出圧力を推定することが可能である。ポンプ吐出圧力の推定値を、払出しライン２０において測定したポンプ吐出圧力の実測値と比較することで、ミニマムフローを制御することができる。 Therefore, the control system 30 is able to estimate the pump discharge pressure at the minimum flow F 0 based on the head H 0 corresponding to the minimum flow F 0 required to maintain the delivery pump 12 in the pump performance curve C. . By comparing the estimated pump discharge pressure to the actual pump discharge pressure measured in the payout line 20, the minimum flow can be controlled.
　ポンプ吐出圧力の実測値が、最小流量Ｆ０におけるポンプ吐出圧力の推定値より高い場合、制御システム３０は、ミニマムフローライン２３の流量を増加させるようにミニフロー弁２４を制御する。これにより、ミニマムフローが不足することを抑制することができる。さらに、制御システム３０は、ポンプ吐出圧力の実測値が、ポンプ吐出圧力の推定値より低い場合は、ミニマムフローライン２３の流量を減少させてもよい。これにより、ミニマムフローが過大になることを抑制することができる。 If the measured pump discharge pressure is higher than the estimated pump discharge pressure at minimum flow F 0 , control system 30 controls miniflow valve 24 to increase the flow in minimum flow line 23 . Thereby, it is possible to suppress the shortage of the minimum flow. Additionally, control system 30 may decrease the flow rate in minimum flow line 23 if the measured pump discharge pressure is lower than the estimated pump discharge pressure. This can prevent the minimum flow from becoming excessive.
　払出しライン２０におけるポンプ吐出圧力の実測値は、圧力指示調節計２５を用いて測定することができる。ポンプ吐出圧力の実測値をポンプ吐出圧力の推定値と比較して、ミニマムフローを制御することにより、制御が容易になる。 The measured value of the pump discharge pressure in the dispensing line 20 can be measured using the pressure indicating controller 25. Control is facilitated by comparing the measured pump discharge pressure to the estimated pump discharge pressure to control the minimum flow.
　上述の制御方法では、既知の最小流量Ｆ０から対応する揚程Ｈ０を求めたが、これとは逆に、既知の揚程から流量を推定することも可能である。制御システム３０は、払出しライン２０において測定したポンプ吐出圧力の実測値と、ポンプ吸込圧力と、ポンプ性能曲線Ｃとを用いて、払出しライン２０における推定流量を求めることができる。 In the control method described above, the corresponding head H 0 was obtained from the known minimum flow rate F 0 , but it is also possible to estimate the flow rate from the known head, conversely. The control system 30 can use the actual pump discharge pressure measured in the payout line 20 , the pump suction pressure, and the pump performance curve C to determine an estimated flow rate in the payout line 20 .
　具体的には、送出ポンプ１２のポンプ吐出圧力から、「ポンプ吸込圧力」を差し引き、さらに、送出ポンプ１２から払出しライン２０までの「配管中の圧力損失」および「高低差を換算した圧力」を加えることで、上述の揚程Ｈ１を換算した圧力が得られる。ポンプ性能曲線Ｃ上で、上述の揚程Ｈ１に対応する流量Ｆ１として、推定流量が求められる。 Specifically, the "pump suction pressure" is subtracted from the pump discharge pressure of the delivery pump 12, and the "pressure loss in the piping" and the "pressure obtained by converting the height difference" from the delivery pump 12 to the dispensing line 20 are calculated. By adding, the pressure obtained by converting the lift H1 described above can be obtained. On the pump performance curve C, an estimated flow rate is obtained as the flow rate F1 corresponding to the head H1 described above.
　推定流量Ｆ１が最小流量Ｆ０より少ない場合、制御システム３０は、ミニマムフローライン２３の流量を増加させるようにミニフロー弁２４を制御する。これにより、ミニマムフローが不足することを抑制することができる。さらに、制御システム３０は、推定流量Ｆ１が最小流量Ｆ０より多い場合は、ミニマムフローライン２３の流量を減少させてもよい。これにより、ミニマムフローが過大になることを抑制することができる。最小流量Ｆ０を推定流量Ｆ１と比較して、ミニマムフローを制御することにより、制御が容易になる。 If the estimated flow rate F 1 is less than the minimum flow rate F 0 , the control system 30 controls the miniflow valve 24 to increase the flow rate in the minimum flow line 23 . Thereby, it is possible to suppress the shortage of the minimum flow. Additionally, control system 30 may decrease the flow rate in minimum flow line 23 if estimated flow rate F1 is greater than minimum flow rate F0. This can prevent the minimum flow from becoming excessive. Controlling the minimum flow by comparing the minimum flow rate F 0 to the estimated flow rate F 1 facilitates control.
　以上説明したように、ポンプ性能曲線Ｃを利用してミニマムフローを制御する方法によれば、払出しライン２０に流量計を設置しなくても、あるいは流量計が送出ポンプ１２ごとに付属されなくても、送出ポンプ１２のミニマムフローを制御することが可能になる。このため、ミニマムフローライン２３の設備を簡素化して、コストを低減することができる。また、ミニマムフローライン２３の流量が過大になることを抑制することにより、ミニマムフローライン２３から液化ガスタンク１０に循環した液化ガス１１の蒸発量の増加等による運転コストを低減することができる。 As described above, according to the method of controlling the minimum flow using the pump performance curve C, there is no need to install a flow meter in the dispensing line 20 or attach a flow meter to each delivery pump 12. Also, it becomes possible to control the minimum flow of the delivery pump 12 . Therefore, the equipment of the minimum flow line 23 can be simplified and the cost can be reduced. In addition, by suppressing the flow rate of the minimum flow line 23 from becoming excessive, it is possible to reduce the operating cost due to an increase in the amount of evaporation of the liquefied gas 11 circulating from the minimum flow line 23 to the liquefied gas tank 10.
　上述のポンプ性能曲線Ｃを用いた制御方法は、ミニマムフローライン２３における過大な流量を抑制することから、実際の流量が最小流量Ｆ０以上である可能性が高い場合に適用することが好ましい。しかし、送出ポンプ１２の起動直後など、流量が少ないことが想定される場合でも、上述の制御を利用して、送出ポンプ１２のポンプ吐出圧力を計測し、最小流量Ｆ０におけるポンプ吐出圧力の推定値より高いかどうかによって、ミニマムフローを制御することも可能である。 Since the control method using the pump performance curve C described above suppresses an excessive flow rate in the minimum flow line 23, it is preferably applied when there is a high possibility that the actual flow rate is equal to or higher than the minimum flow rate F0 . However, even when the flow rate is assumed to be small, such as immediately after the start-up of the delivery pump 12, the pump discharge pressure of the delivery pump 12 is measured using the control described above, and the pump delivery pressure at the minimum flow rate F0 is estimated. It is also possible to control the minimum flow by whether it is higher than the value.
　上述の説明では、払出しライン２０と同様に、ミニマムフローライン２３も２以上の送出ポンプ１２に共用されている例示を示したが、上述のポンプ性能曲線Ｃを用いた制御方法は、この例示に限定されるものではない。上述の制御方法は、送出ポンプ１２ごとに、払出しライン２０またはミニマムフローライン２３が一対一で設置される場合にも適用可能である。 In the above description, an example in which the minimum flow line 23 is shared by two or more delivery pumps 12 as well as the payout line 20 was shown. It is not limited. The control method described above can also be applied when the payout line 20 or the minimum flow line 23 is installed one-to-one for each delivery pump 12 .
＜送出ポンプを起動した直後の制御方法＞
　実際の流量が最小流量Ｆ０より少ないことがあらかじめ想定される場合は、特定の条件において、上述のポンプ性能曲線Ｃを用いた制御方法を用いることなく、あらかじめミニマムフローライン２３に最小流量Ｆ０以上の液化ガス１１を流すように制御してもよい。 <Control method immediately after starting the delivery pump>
If it is assumed in advance that the actual flow rate is less than the minimum flow rate F 0 , the minimum flow rate F 0 can be supplied to the minimum flow line 23 in advance without using the above-described control method using the pump performance curve C under specific conditions. You may control so that the above liquefied gas 11 may flow.
　例えば、送出ポンプ１２の起動直後は、流量が少ないことが想定されるため、送出ポンプ１２の起動から所定の時間において、ミニフロー弁２４を通じてミニマムフローライン２３に液化ガス１１を流すようにしてもよい。この場合、所定の時間内には、ミニマムフローライン２３の流量が過大になる可能性もあるが、時間が限られているため、無駄になる量は比較的少ない。また、起動から開始する時間だけを制御因子とするため、制御が容易になる。 For example, immediately after the start-up of the delivery pump 12, it is assumed that the flow rate is small, so the liquefied gas 11 may be flowed through the minimum flow line 23 through the mini-flow valve 24 for a predetermined time after the start-up of the delivery pump 12. good. In this case, there is a possibility that the flow rate of the minimum flow line 23 may become excessive within a predetermined period of time, but since the period of time is limited, the amount that is wasted is relatively small. In addition, since only the time from activation is used as a control factor, control becomes easier.
　さらに、送出ポンプ１２の起動直後に一定の流量を確保する制御方法を用いる場合において、同一の液化ガスタンク１０に設置された２以上の送出ポンプ１２を同時に運転する場合は、運転中の送出ポンプ１２の台数を考慮してもよい。 Furthermore, when using a control method that ensures a constant flow rate immediately after starting the delivery pump 12, when simultaneously operating two or more delivery pumps 12 installed in the same liquefied gas tank 10, the delivery pump 12 in operation may be considered.
　例えば、２以上の送出ポンプ１２のいずれかを起動する際、制御システム３０は、同一の液化ガスタンク１０において他の送出ポンプ１２が運転されていないことを確認したときは、最初の送出ポンプ１２の起動から所定の時間において、ミニフロー弁２４を通じてミニマムフローライン２３に液化ガスを流してもよい。 For example, when starting any of the two or more delivery pumps 12, the control system 30 confirms that no other delivery pumps 12 are operating in the same liquefied gas tank 10, the first delivery pump 12 A liquefied gas may be flowed through the minimum flow line 23 through the miniflow valve 24 at a predetermined time after startup.
　これにより、最初の送出ポンプ１２の起動から所定の時間は流量が少ないことを想定してミニマムフローを確保するため、制御が容易になる。起動から所定の時間を経過した後は、状況に応じて、ミニマムフローライン２３における流量を増減して制御することにより、必要以上の流量が流れることを抑制でき、運転コストを低減することができる。 As a result, a minimum flow is ensured on the assumption that the flow rate will be low for a predetermined period of time after the first start-up of the delivery pump 12, making control easier. After a predetermined time has passed since the startup, by increasing or decreasing the flow rate in the minimum flow line 23 according to the situation, it is possible to suppress the flow rate more than necessary, and the operating cost can be reduced. .
　制御システム３０は、送出ポンプ１２の運転状態やモータ等の起動状態などから、運転中の送出ポンプ１２の番号や台数を確認することができる。これにより、制御システム３０は、他の送出ポンプ１２が運転されているか否かを判別する。 The control system 30 can confirm the number and number of the delivery pumps 12 in operation based on the operating status of the delivery pumps 12 and the activation status of the motors and the like. This allows control system 30 to determine whether other delivery pumps 12 are operating.
＜ミニフロー弁の容量係数を用いた制御方法＞
　ミニマムフローライン２３に設置されたミニフロー弁２４は、容量係数を有する。容量係数の定義はミニフロー弁２４のベンダーによって異なるが、例えばＣｖ値でもＫｖ値でもよい。容量係数は、流量Ｑと流体の比重Ｇと差圧ΔＰとの間に特定の関係があることを示す定数である。 <Control method using the capacity coefficient of the miniflow valve>
A miniflow valve 24 installed in the minimum flow line 23 has a capacity coefficient. The definition of capacity factor varies by vendor of the miniflow valve 24, but may be, for example, a Cv value or a Kv value. The capacity coefficient is a constant indicating that there is a specific relationship between the flow rate Q, the specific gravity G of the fluid, and the differential pressure ΔP.
　制御システム３０は、圧力指示調節計２５の圧力値と、ミニフロー弁２４の容量係数とから、ミニフロー弁２４における流量を計算することができる。これにより、制御システム３０は、ミニマムフローが維持されているか否かを判別することができる。制御システム３０は、信号経路３４，３５を介して圧力指示調節計２５およびミニフロー弁２４との間で、直接または間接的に信号を送信または受信する。信号経路３４，３５は、ケーブル等の有線でもよく、電波等の無線でもよい。 The control system 30 can calculate the flow rate at the miniflow valve 24 from the pressure value of the pressure indicating controller 25 and the capacity coefficient of the miniflow valve 24 . Thereby, the control system 30 can determine whether or not the minimum flow is maintained. Control system 30 sends or receives signals directly or indirectly to pressure indicating controller 25 and miniflow valve 24 via signal paths 34,35. The signal paths 34 and 35 may be wired such as cables or wireless such as radio waves.
　さらに制御システム３０は、容量係数を用いて算出されたミニフロー弁２４における流量の計算値がミニマムフローの維持に不足するとき、ミニフロー弁２４における流量を増加させるように制御することができる。これにより、ミニマムフローをより確実に維持することができる。 Furthermore, the control system 30 can control to increase the flow rate in the miniflow valve 24 when the calculated value of the flow rate in the miniflow valve 24 calculated using the capacity coefficient is insufficient to maintain the minimum flow. Thereby, the minimum flow can be maintained more reliably.
　実施形態の制御方法では、基本的には、上述のポンプ性能曲線Ｃを用いた制御方法が用いられる。送出ポンプ１２を起動した直後では、上述した（１）ポンプ性能曲線Ｃを用いた制御方法、（２）起動直後の所定の時間に一定の流量を確保する制御方法、（３）ミニフロー弁２４の容量係数を用いた制御方法のいずれか１または２以上を用いることで、ミニマムフローの維持をより確実にすることができる。 The control method of the embodiment basically uses the control method using the pump performance curve C described above. Immediately after starting the delivery pump 12, the above-described (1) control method using the pump performance curve C, (2) control method for ensuring a constant flow rate at a predetermined time immediately after starting, and (3) the miniflow valve 24 By using one or more of the control methods using the capacity coefficient of , it is possible to more reliably maintain the minimum flow.
　また、ミニマムフローライン２３が２以上の送出ポンプ１２に共用されていて、２以上の送出ポンプ１２が運転中の場合は、ミニフロー弁２４における流量も、２以上の送出ポンプ１２の流量の合計値となる。このため、ミニフロー弁２４の容量係数を用いた制御方法では、１の送出ポンプ１２のみが運転中であるときには、容量係数を用いて算出された流量を、運転中の送出ポンプ１２による流量とみなすことができる。２以上の送出ポンプ１２が運転中であるときには、容量係数を用いて算出された流量は、２以上の送出ポンプ１２による流量の合計値となる。このため、制御システム３０は、運転中の送出ポンプ１２の台数に応じて、１台当たりの流量を算出して制御に用いてもよい。 In addition, when the minimum flow line 23 is shared by two or more delivery pumps 12 and the two or more delivery pumps 12 are in operation, the flow rate at the miniflow valve 24 is also the sum of the flow rates of the two or more delivery pumps 12. value. Therefore, in the control method using the capacity coefficient of the miniflow valve 24, when only one delivery pump 12 is in operation, the flow rate calculated using the capacity coefficient is the same as the flow rate by the delivery pump 12 in operation. can be regarded as When two or more delivery pumps 12 are in operation, the flow rate calculated using the capacity factor is the sum of the flow rates of the two or more delivery pumps 12 . Therefore, the control system 30 may calculate the flow rate per pump according to the number of the pumps 12 in operation and use it for control.
　送出ポンプ１２を起動した後、下流に送られる払出し流量が、送出ポンプ１２の最小流量Ｆ０よりも多くなった場合は、ポンプ吐出圧力が低下する。このため、上述したポンプ性能曲線Ｃを用いた制御方法の結果として、ミニフロー弁２４は自動的に閉状態となる。 After starting the delivery pump 12, if the delivery flow sent downstream is greater than the minimum flow rate F0 of the delivery pump 12, the pump discharge pressure will drop. Therefore, as a result of the control method using the pump performance curve C described above, the miniflow valve 24 is automatically closed.
＜送出ポンプを追起動するときの制御方法＞
　同一の液化ガスタンク１０に設けられた２以上の送出ポンプ１２のいずれかを起動する際、制御システム３０は、追起動しようとする送出ポンプ１２とは異なる送出ポンプ１２が運転されていることを確認したときは、最初の送出ポンプ１２の起動と異なる制御を用いてもよい。 <Control method when additionally starting the delivery pump>
When starting one of the two or more delivery pumps 12 provided in the same liquefied gas tank 10, the control system 30 confirms that the delivery pump 12 different from the delivery pump 12 to be additionally started is being operated. When it does, a different control than the initial delivery pump 12 activation may be used.
　２台目以降の送出ポンプ１２を追起動する際、運転中の送出ポンプ１２の流量の合計値が多い場合は、その一部の流量を追起動される送出ポンプ１２に分担させることで、ミニマムフローを容易に確保できる場合がある。このため、制御システムは、払出しライン２０の下流における流量の合計値を算出し、この合計値が、新たに追起動する送出ポンプ１２および運転中の送出ポンプ１２のミニマムフローの維持に十分か否かを判別することが好ましい。 When the second and subsequent delivery pumps 12 are additionally started, if the total value of the flow rate of the delivery pumps 12 in operation is large, a part of the flow rate is shared by the delivery pumps 12 to be additionally started, thereby minimizing the Flow may be easily secured. Therefore, the control system calculates the total flow rate downstream of the payout line 20, and determines whether or not this total value is sufficient to maintain the minimum flow of the newly started delivery pump 12 and the delivery pump 12 in operation. It is preferable to determine whether
　図１には、払出しライン２０の下流において、液化ガス１１から気化器４５で気化した状態のガスをガス供給部４６に供給する払出し配管４１、保冷循環５４のために液化ガス１１を供給する払出し配管５１を示す。また、図２には、内航船出荷６４のために液化ガス１１を供給する払出し配管６１、ローリー出荷７４のために液化ガス１１を供給する払出し配管７１を示す。プライマリーポンプとなる送出ポンプ１２による圧力が液化ガス１１の移送に不足する場合は、払出し配管４１にセカンダリーポンプ４２を設けてもよい。ガス供給部４６は、例えばＬＮＧの場合、発電所、都市ガス製造所等にＬＮＧを供給する。 In FIG. 1, downstream of the payout line 20, a payout pipe 41 for supplying the gas in a state of being vaporized by the vaporizer 45 from the liquefied gas 11 to the gas supply unit 46, and a payout pipe 41 for supplying the liquefied gas 11 for the cold insulation circulation 54 A pipe 51 is shown. FIG. 2 also shows a payout pipe 61 for supplying the liquefied gas 11 for domestic ship shipment 64 and a payout pipe 71 for supplying the liquefied gas 11 for lorry shipment 74 . A secondary pump 42 may be provided in the delivery pipe 41 when the pressure of the delivery pump 12 serving as the primary pump is insufficient to transfer the liquefied gas 11 . For example, in the case of LNG, the gas supply unit 46 supplies LNG to power plants, city gas production plants, and the like.
　それぞれの払出し配管４１，５１，６１，７１には、流量計４３，５２，６２，７２とバルブ４４，５３，６３，７３が設置されている。これらの流量計４３，５２，６２，７２は、信号経路３６を介して制御システム３０に送信される。信号経路３６は、ケーブル等の有線でもよく、電波等の無線でもよい。図１および図２に示す払出し配管４１，５１，６１，７１の供給先は模式的な例示であり、数や組み合わせ等は適宜変更可能である。鉄道輸送等、例示した以外の供給先にも適用可能である。 Flowmeters 43, 52, 62, 72 and valves 44, 53, 63, 73 are installed in the respective payout pipes 41, 51, 61, 71. These flow meters 43 , 52 , 62 , 72 are transmitted to control system 30 via signal path 36 . The signal path 36 may be wired such as a cable or wireless such as radio waves. The supply destinations of the delivery pipes 41, 51, 61, and 71 shown in FIGS. 1 and 2 are schematic examples, and the number, combination, and the like can be changed as appropriate. It can also be applied to supply destinations other than those exemplified, such as railway transportation.
　下流における払出し流量の合計値が、新たに追起動する送出ポンプ１２および運転中の送出ポンプ１２のミニマムフローの維持に十分である場合、制御システム３０は、ミニフロー弁２４が閉状態のままでも、追起動に支障がないと判断することができる。また、上述した送出ポンプ１２を起動した直後の制御方法に従い、送出ポンプ１２の追起動から所定の時間において、ミニフロー弁２４を通じてミニマムフローライン２３に液化ガス１１を流すように制御してもよい。 If the total downstream dispensed flow rate is sufficient to maintain the minimum flow of the newly restarted delivery pump 12 and the running delivery pump 12, the control system 30 will continue to operate the miniflow valve 24 even if the miniflow valve 24 remains closed. , it can be determined that there is no problem with additional start-up. Further, according to the control method immediately after starting the delivery pump 12 described above, the liquefied gas 11 may be controlled to flow through the minimum flow line 23 through the mini flow valve 24 at a predetermined time after the additional start of the delivery pump 12. .
　下流における払出し流量の合計値を用いた制御方法によれば、２台目以降となる送出ポンプ１２の起動に際して、運転中の送出ポンプ１２の流量が、運転中の送出ポンプ１２のミニマムフローと２台目以降に起動する送出ポンプ１２のミニマムフローの合計値より多いことを下流の流量計４３，５２，６２，７２で確認することにより、２台目以降に起動する送出ポンプ１２のミニマムフローをより確実に維持することができる。 According to the control method using the total value of the delivery flow rate in the downstream, when starting the second and subsequent delivery pumps 12, the flow rate of the delivery pump 12 in operation is equal to the minimum flow of the delivery pump 12 in operation. By confirming with the downstream flow meters 43, 52, 62, 72 that the total value of the minimum flow of the delivery pumps 12 to be started after the first unit is larger than the total value, the minimum flow of the delivery pumps 12 to be started after the second unit is determined. can be maintained more reliably.
　以上、本発明を好適な実施形態に基づいて説明してきたが、本発明は上述の実施形態に限定されず、本発明の要旨を逸脱しない範囲で種々の改変が可能である。改変としては、各実施形態における構成要素の追加、置換、省略、その他の変更が挙げられる。また、２以上の実施形態に用いられた構成要素を適宜組み合わせることも可能である。 Although the present invention has been described above based on the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. Modifications include additions, substitutions, omissions, and other changes of components in each embodiment. Moreover, it is also possible to appropriately combine components used in two or more embodiments.
　本発明の液化ガス受入設備および制御方法は、特に限定されないが、ＬＮＧ受入基地、ＬＰＧ受入基地、貯蔵所等に利用することができる。 The liquefied gas receiving facility and control method of the present invention are not particularly limited, but can be used for LNG receiving bases, LPG receiving bases, storage facilities, and the like.
Ｃ…ポンプ性能曲線、Ｆ０…最小流量、Ｆ１…払出しラインにおける流量（推定流量）、Ｈ０…最小流量に対応する揚程、Ｈ１…流量Ｆ１に対応する揚程、１０…液化ガスタンク、１０ａ…頂部、１０ｂ…底部、１１…液化ガス、１１ａ…気相部、１１ｂ…液面、１２…送出ポンプ、１２ａ…吐出部、１２ｂ…吸込部、１３…圧力計、１４…密度計、１５…レベル計、１６…測定部、２０…払出しライン、２１…支線部、２２…幹線部、２３…ミニマムフローライン、２４…ミニフロー弁、２５…圧力指示調節計、３０…制御システム、３１，３２，３３，３４，３５，３６…信号経路、４１，５１，６１，７１…払出し配管、４２…セカンダリーポンプ、４３，５２，６２，７２…流量計、４４，５３，６３，７３…バルブ、４５…気化器、４６…ガス供給部、５４…保冷循環、６４…内航船出荷、７４…ローリー出荷、１００…液化ガス受入設備。 C ... pump performance curve, F 0 ... minimum flow rate, F 1 ... flow rate (estimated flow rate) in delivery line, H 0 ... lift corresponding to minimum flow rate, H 1 ... lift corresponding to flow rate F 1 , 10 ... liquefied gas tank, DESCRIPTION OF SYMBOLS 10a... Top part 10b... Bottom part 11... Liquefied gas 11a... Gas phase part 11b... Liquid surface 12... Sending pump 12a... Discharge part 12b... Suction part 13... Pressure gauge 14... Density meter 15 ... Level meter, 16 ... Measurement part, 20 ... Delivery line, 21 ... Branch line part, 22 ... Main line part, 23 ... Minimum flow line, 24 ... Mini flow valve, 25 ... Pressure indicator controller, 30 ... Control system, 31 32, 33, 34, 35, 36... signal path, 41, 51, 61, 71... discharge pipe, 42... secondary pump, 43, 52, 62, 72... flow meter, 44, 53, 63, 73... valve, 45...Vaporizer, 46...Gas supply unit, 54...Refrigerant circulation, 64...Domestic ship shipment, 74...Lorry shipment, 100...Liquefied gas receiving facility.

Claims (9)

  1. 　液化ガスを貯蔵する液化ガスタンクと、
    　前記液化ガスタンクから液化ガスを液体の状態で払い出す払出しラインと、
    　前記液化ガスタンクから液化ガスを前記払出しラインに送出する送出ポンプと、
    　前記払出しラインから分岐して、液化ガスを前記液化ガスタンクに戻すことが可能なミニマムフローラインと、
    　制御システムと、を備える液化ガス受入設備であって、
    　前記制御システムは、前記液化ガスタンクに貯蔵されている液化ガスの密度および液面レベルと、前記液化ガスタンク内における前記液化ガスの液面上の気相圧力とから、前記液化ガスの液面下における前記送出ポンプのポンプ吸込圧力を算出すると共に、前記ポンプ吸込圧力と、前記送出ポンプのポンプ性能曲線とを用いて、前記送出ポンプのミニマムフローを制御することを特徴とする液化ガス受入設備。     a liquefied gas tank for storing liquefied gas;
    a dispensing line for dispensing the liquefied gas from the liquefied gas tank in a liquid state;
    a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line;
    a minimum flow line branching from the payout line and capable of returning the liquefied gas to the liquefied gas tank;
    A liquefied gas receiving facility comprising a control system,
    From the density and liquid level of the liquefied gas stored in the liquefied gas tank and the gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank, the control system determines A liquefied gas receiving facility, wherein a pump suction pressure of said delivery pump is calculated, and a minimum flow of said delivery pump is controlled using said pump suction pressure and a pump performance curve of said delivery pump.
  2. 　前記制御システムは、前記ポンプ性能曲線における、前記送出ポンプの維持に必要な最小流量に対応する揚程を換算した圧力と、前記ポンプ吸込圧力から、前記最小流量におけるポンプ吐出圧力を推定し、前記ポンプ吐出圧力の推定値を、前記払出しラインにおいて測定したポンプ吐出圧力の実測値と比較して、
    　前記ポンプ吐出圧力の実測値が、前記ポンプ吐出圧力の推定値より高い場合は、前記ミニマムフローラインの流量を増加させ、
    　前記ポンプ吐出圧力の実測値が、前記ポンプ吐出圧力の推定値より低い場合は、前記ミニマムフローラインの流量を減少させることを特徴とする請求項１に記載の液化ガス受入設備。     The control system estimates the pump discharge pressure at the minimum flow rate from the pump suction pressure and the pressure converted to the head corresponding to the minimum flow rate required to maintain the delivery pump in the pump performance curve, Comparing the estimated discharge pressure to the measured pump discharge pressure measured in the dispensing line,
    when the measured value of the pump discharge pressure is higher than the estimated value of the pump discharge pressure, increasing the flow rate of the minimum flow line;
    2. The liquefied gas receiving facility according to claim 1, wherein the flow rate of said minimum flow line is reduced when the measured value of said pump discharge pressure is lower than said estimated value of said pump discharge pressure.
  3. 　前記制御システムは、前記払出しラインにおいて測定したポンプ吐出圧力の実測値と、前記ポンプ吸込圧力と、前記ポンプ性能曲線とを用いて、前記払出しラインにおける推定流量を求め、
    　前記推定流量が、前記送出ポンプの維持に必要な最小流量より少ない場合は、前記ミニマムフローラインの流量を増加させ、
    　前記推定流量が、前記送出ポンプの維持に必要な最小流量より多い場合は、前記ミニマムフローラインの流量を減少させることを特徴とする請求項１に記載の液化ガス受入設備。     The control system obtains an estimated flow rate in the payout line using the measured value of the pump discharge pressure measured in the payout line, the pump suction pressure, and the pump performance curve,
    if the estimated flow rate is less than the minimum flow rate required to maintain the delivery pump, increasing the flow rate in the minimum flow line;
    2. The liquefied gas receiving facility of claim 1, wherein the flow rate of the minimum flow line is reduced if the estimated flow rate is greater than the minimum flow rate required to maintain the delivery pump.
  4. 　前記液化ガス受入設備は、同一の液化ガスタンクに対し、２以上の送出ポンプと、前記２以上の送出ポンプに共用される払出しラインと、を備え、
    　前記ミニマムフローラインには、ミニフロー弁が配置され、
    　前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていないことを確認したときは、最初の送出ポンプの起動から所定の時間において、前記ミニフロー弁を通じて前記ミニマムフローラインに液化ガスを流すことを特徴とする請求項１～３のいずれか１項に記載の液化ガス受入設備。     The liquefied gas receiving facility comprises two or more delivery pumps for the same liquefied gas tank, and a delivery line shared by the two or more delivery pumps,
    A miniflow valve is arranged in the minimum flow line,
    When activating any of the two or more delivery pumps, the control system confirms that no other delivery pump is operating in the same liquefied gas tank, a predetermined time from the start of the first delivery pump 4. The liquefied gas receiving facility according to any one of claims 1 to 3, characterized in that the liquefied gas is passed through the minimum flow line through the mini-flow valve.
  5. 　前記払出しラインには、前記液化ガスの圧力指示調節計が配置され、
    　前記制御システムは、前記圧力指示調節計の圧力値と、前記ミニフロー弁の容量係数とから、前記ミニフロー弁における流量を計算し、前記ミニマムフローが維持されているか否かを判別することを特徴とする請求項４に記載の液化ガス受入設備。     A pressure indicator controller for the liquefied gas is arranged in the delivery line,
    The control system calculates the flow rate in the miniflow valve from the pressure value of the pressure indicating controller and the capacity coefficient of the miniflow valve, and determines whether the minimum flow is maintained. The liquefied gas receiving facility according to claim 4.
  6. 　前記制御システムは、前記ミニフロー弁における流量の計算値が前記ミニマムフローの維持に不足するとき、前記ミニフロー弁における流量を増加させることを特徴とする請求項５に記載の液化ガス受入設備。 The liquefied gas receiving facility according to claim 5, wherein the control system increases the flow rate at the mini-flow valve when the calculated value of the flow rate at the mini-flow valve is insufficient to maintain the minimum flow.
  7. 　前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていることを確認したときは、前記払出しラインの下流における流量の合計値を算出し、この合計値が、新たに起動する送出ポンプおよび運転中の送出ポンプのミニマムフローの維持に十分か否かを判別することを特徴とする請求項４～６のいずれか１項に記載の液化ガス受入設備。 When the control system confirms that another delivery pump is operating in the same liquefied gas tank when activating one of the two or more delivery pumps, the total value of the flow rate downstream of the delivery line is calculated, and it is determined whether or not this total value is sufficient to maintain the minimum flow of the newly started delivery pump and the delivery pump in operation. A liquefied gas receiving facility as described.
  8. 　前記制御システムは、前記２以上の送出ポンプのいずれかを起動する際、同一の液化ガスタンクにおいて他の送出ポンプが運転されていることを確認したときは、新たに起動する送出ポンプの起動から所定の時間において、前記ミニフロー弁を通じて前記ミニマムフローラインに液化ガスを流すことを特徴とする請求項４～７のいずれか１項に記載の液化ガス受入設備。 When activating one of the two or more delivery pumps, the control system confirms that another delivery pump is being operated in the same liquefied gas tank, the control system, from the activation of the newly activated delivery pump 8. The liquefied gas receiving facility according to any one of claims 4 to 7, characterized in that the liquefied gas is passed through the minimum flow line through the mini-flow valve at the time of .
  9. 　液化ガスを貯蔵する液化ガスタンクと、
    　前記液化ガスタンクから液化ガスを液体の状態で払い出す払出しラインと、
    　前記液化ガスタンクから液化ガスを前記払出しラインに送出する送出ポンプと、
    　前記払出しラインから分岐して、液化ガスを前記液化ガスタンクに戻すことが可能なミニマムフローラインと、を備える液化ガス受入設備の制御方法であって、
    　前記液化ガスタンクに貯蔵されている液化ガスの密度および液面レベルと、前記液化ガスタンク内における前記液化ガスの液面上の気相圧力とから、前記液化ガスの液面下における前記送出ポンプのポンプ吸込圧力を算出すると共に、前記ポンプ吸込圧力と、前記送出ポンプのポンプ性能曲線とを用いて、前記送出ポンプのミニマムフローを制御することを特徴とする液化ガス受入設備の制御方法。     a liquefied gas tank for storing liquefied gas;
    a dispensing line for dispensing the liquefied gas from the liquefied gas tank in a liquid state;
    a delivery pump for delivering the liquefied gas from the liquefied gas tank to the delivery line;
    A control method for a liquefied gas receiving facility comprising a minimum flow line branching from the payout line and capable of returning the liquefied gas to the liquefied gas tank,
    From the density and liquid level of the liquefied gas stored in the liquefied gas tank and the gas phase pressure above the liquid level of the liquefied gas in the liquefied gas tank, the pump of the delivery pump below the liquid level of the liquefied gas A control method for a liquefied gas receiving facility, comprising calculating a suction pressure and controlling a minimum flow of the delivery pump by using the pump suction pressure and a pump performance curve of the delivery pump.
PCT/JP2021/043817 2021-11-30 2021-11-30 Liquefied gas receiving facility and control method for same WO2023100231A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004204768A (en) * 2002-12-25 2004-07-22 Ishikawajima Plant Construction Co Ltd Method and device for delivering small quantity of low temperature liquid by pump
JP2005308149A (en) * 2004-04-23 2005-11-04 Iwatani Internatl Corp Demand equipment interlocking type cryogenic liquefied gas feeder
JP2007175594A (en) * 2005-12-27 2007-07-12 Ishikawajima Plant Construction Co Ltd Facility for recovering gas emitted to atmospheric air and removing malodorous component

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004204768A (en) * 2002-12-25 2004-07-22 Ishikawajima Plant Construction Co Ltd Method and device for delivering small quantity of low temperature liquid by pump
JP2005308149A (en) * 2004-04-23 2005-11-04 Iwatani Internatl Corp Demand equipment interlocking type cryogenic liquefied gas feeder
JP2007175594A (en) * 2005-12-27 2007-07-12 Ishikawajima Plant Construction Co Ltd Facility for recovering gas emitted to atmospheric air and removing malodorous component

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