JP2018179059A - Liquefied gas receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly cool receiving piping in a receiving facility.SOLUTION: A liquefied gas receiving facility with receiving piping that is connected to a tank for storing a liquefied gas includes: liquid level calculation means for calculating a liquid level height of the liquefied gas inside the receiving piping; density acquisition means for acquiring a density of a liquid phase of the liquefied gas that is stored in the receiving piping; and liquid level correction means for correcting the liquid level height based on the density of the liquefied gas that is acquired by the density acquisition means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquefied gas receiving apparatus.

  A receiving facility including a tank for storing liquefied gas is regularly supplied with liquefied gas from a tanker. For this reason, the receiving facility has a receiving pipe connected to the tanker and the tank. The receiving pipe is cooled by filling the inside with liquefied gas even while the liquefied gas is not supplied from the tanker. In such a receiving pipe, the cooling performance is maintained by monitoring the liquid level of the liquefied gas inside and adjusting the liquid level.

  For example, Patent Document 1 discloses a configuration in which a liquid level detector for detecting the liquid level (liquid level height) at the rising portion is provided at the rising portion of the receiving pipe connected to the storage tank (tank). . The liquid level controller adjusts the liquid level at the rising portion on the basis of the detection result of the liquid level detector.

JP 7-119893 A

  A detector for detecting the liquid level height of the receiving pipe generally comprises a gas phase pressure gauge for detecting a gas phase pressure above the liquid level, and a liquid phase pressure gauge for detecting a liquid phase pressure below the liquid level. The liquid level is calculated from the density of the liquefied gas, and the gas phase pressure and the liquid phase pressure, which are predetermined. However, as time passes, as for liquefied gas, one having a light specific gravity among the components floats up to the liquid surface and is first vaporized to condense the liquid phase. Under the present circumstances, although the change in liquid level height does not appear in the detector which detects liquid level height because the vaporized material of liquefied gas stays near liquid level, the liquid level is actually concentrated by liquefied gas. May have fallen. If the liquid level of the liquefied gas in the receiving pipe can not be accurately maintained, the receiving pipe can not be properly cooled.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to appropriately cool a receiving pipe in a receiving facility.

  The present invention is, in order to solve the above problems, a first means according to the present invention is a liquefied gas receiving facility comprising a receiving pipe connected to a tank for storing liquefied gas, the above-mentioned inside of the receiving pipe being characterized by Liquid level calculation means for calculating the liquid level height of the liquefied gas, Density acquisition means for acquiring the density of the liquid phase of the liquefied gas stored in the receiving pipe, and the liquefied gas acquired by the density acquisition means And a liquid level correction unit configured to correct the liquid level height based on the density.

  As a second means, in the first means, the density acquisition means calculates the density based on the differential pressure of the liquid phase of the liquefied gas.

  As a third means, in the second means, the density acquiring means is provided at a position different from the first pressure gauge which measures the pressure of the liquid phase of the liquefied gas in the vertical direction from the first pressure gauge. And a second pressure gauge for measuring the pressure of the liquid phase of the liquefied gas, and a density calculation unit for calculating the density of the liquefied gas based on the pressure of the liquid phase obtained from the first pressure gauge and the second pressure gauge And a configuration of

  As a fourth means, in the third means, the liquid level calculating means is a gas phase pressure gauge for measuring the pressure of the gas phase inside the receiving pipe, and a liquid for measuring the pressure of the liquid phase of the liquefied gas A phase pressure gauge is provided, and the liquid phase pressure gauge is configured to be used also as the first pressure gauge or the second pressure gauge.

  As a fifth means, any one of the first to fourth means is provided with a liquid level adjusting means for adjusting the liquid level based on the liquid level corrected by the liquid level correcting means. The liquid level adjusting means is connected to the receiving pipe to obtain a valve for adjusting the inflow of the liquefied gas to the receiving pipe, and the liquid level height corrected by the liquid level correcting means. A control unit is provided to adjust the liquid level of the receiving pipe by opening and closing the valve.

  According to the present invention, the density acquisition means acquires the density of the liquefied gas stored in the receiving pipe. Thereby, the accurate density of the liquefied gas in the liquid phase can be obtained. Furthermore, the liquid level correction means can correct the calculated liquid level height with the density acquired by the density acquisition means, so that the liquid level height can be corrected accurately. Therefore, the correct liquid level in the receiving pipe can be obtained, and the receiving pipe can be properly cooled.

It is a schematic diagram including the whole of receiving facility in one embodiment of the present invention. It is an expansion schematic diagram including the perpendicular piping part with which receiving facilities in one embodiment of the present invention are provided.

  Hereinafter, an embodiment of a liquefied gas receiving facility according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

FIG. 1 is a schematic view including the entire receiving facility 1 in the present embodiment. Moreover, FIG. 2 is an expansion schematic diagram containing the vertical piping part 2c with which the reception facility 1 in this embodiment is equipped.
The receiving facility 1 is a facility connected to a delivery pipe 120 connected via a joint 110 to an LNG tanker 100 loaded and transported with liquefied natural gas X. Such a receiving facility 1 includes a receiving pipe 2, a storage tank 3, a liquid level calculating unit 4 (liquid level calculating unit), and a density acquiring unit 5 (density acquiring unit) as shown in FIGS. And a liquid level correction unit 6 (liquid level correction means) and a liquid level adjustment unit 7 (liquid level adjustment means).

  The receiving pipe 2 is a pipe connected to the delivery pipe 120 and connected to the storage tank 3. Receiving pipe 2 is divided into a receiving main pipe 2a into which liquid phase X1 flows in and an receiving branch pipe 2b into which gas phase X2 flows in, and each of receiving main pipe 2a and receiving branch pipe 2b is It is connected to the upper surface of the storage tank 3. Further, in the receiving pipe 2, the vertical pipe portion 2 c on the upstream side of the receiving main pipe 2 a and the receiving branch pipe 2 b is disposed along the vertical direction up to the upper surface of the storage tank 3. Note that the vertical direction in the present invention is not limited to the case of being perpendicular to the ground, but also includes the case of being obliquely inclined to the ground. In the vertical piping portion 2c, the liquid phase X1 is stored to the vicinity of the upper end, and the piping member is cooled by the liquid phase X1. Furthermore, the receiving pipe 2 has a valve 2d on the upstream side of the vertical pipe portion 2c, and the flow rate of the liquefied natural gas X on the downstream side of the valve 2d is adjusted.

  The storage tank 3 is a tank for receiving the liquefied natural gas X from the tanker 100 via the receiving pipe 2. Such a storage tank 3 is, for example, a double shell structure cylindrical type in which a cold insulating material is filled between an inner tank and an outer tank, and has a tank portion 3b whose outer peripheral surface is covered with concrete 3a. ing.

  As shown in FIG. 2, the liquid level calculation unit 4 includes a vapor pressure gauge 4 a, a liquid pressure gauge 4 b, and a calculation unit 4 c. The gas phase pressure gauge 4a is provided at the upper end of the vertical piping 2c, and measures the pressure of the gas staying at the upper end of the vertical piping 2c. The liquid phase pressure gauge 4b is provided at the lower end of the vertical piping portion 2c, and measures the pressure of the liquid phase X1 stored in the vertical piping portion 2c. The calculation unit 4c stores the density of the liquefied natural gas X in advance, obtains pressure values from the gas phase pressure gauge 4a and the liquid phase pressure gauge 4b, respectively, and uses the pressure value of the gas phase and the pressure value of the liquid phase. The liquid level height of the liquid phase X1 in the vertical piping portion 2c is calculated.

  The density acquisition unit 5 includes a first pressure gauge 5a, a second pressure gauge 5b, and a density calculation unit 5c. The first pressure gauge 5a and the second pressure gauge 5b are disposed between the gas pressure gauge 4a and the liquid pressure gauge 4b, and measure the pressure of the liquid phase X1. The second pressure gauge 5b is disposed below the first pressure gauge 5a in the vertical direction. Further, the distance in the vertical direction between the first pressure gauge 5a and the second pressure gauge 5b is known. The density calculation unit 5c acquires pressure values of the first pressure gauge 5a and the second pressure gauge 5b, and calculates the density of the liquid phase X1 from the pressure difference.

  The liquid level correction unit 6 acquires the liquid level height from the liquid level calculation unit 4 and further corrects the liquid level based on the density of the liquid phase X1 acquired from the density acquisition unit 5. The liquid level adjustment unit 7 includes a pump 7a, an adjustment valve 7b, and a control unit 7c. The pump 7a is accommodated in the tank portion 3b of the storage tank 3 as shown in FIG. 1, and pumps the liquid phase X1 stored in the tank portion 3b to the vertical piping portion 2c through piping. The adjustment valve 7 b is provided between the vertical piping 2 c and the pump 7 a. The control unit 7 c controls the pump 7 a and the adjustment valve 7 b based on the corrected liquid level height acquired from the liquid level correction unit 6 to adjust the liquid level height of the vertical piping unit 2 c.

  When the LNG tanker 100 is connected to the joint 110 and the liquefied natural gas X is supplied from the LNG tanker 100 to the receiving facility 1 through the discharge pipe 120, the valve 2d is opened, and the storage tank 3 is connected through the receiving pipe 2 Liquefied natural gas X is stored. When a predetermined amount of liquefied natural gas X is stored in the storage tank 3, the valve 2d is closed. As a result, the liquefied natural gas X on the downstream side of the vertical piping portion 2c in the receiving piping 2 flows into the storage tank 3, and the liquefied natural gas X remains in the vertical piping portion 2c.

  It is contained in liquefied natural gas X when liquefied natural gas X is stored in vertical piping part 2c for a long period (about several days to several months) in the state where liquefied natural gas X remains in vertical piping part 2c. The component with a low specific gravity is vaporized and separated into a liquid phase X1 and a gas phase X2. For this reason, the liquid phase X1 becomes smaller than the volume of the original liquefied natural gas X, and the liquid level height of the liquid phase X1 in the vertical piping portion 2c decreases. In addition, the gas phase X2 stays in the upper part of the vertical piping portion 2c.

  In the receiving facility 1 as described above, the liquid level calculation unit 4 measures the pressure of the gas phase of the vertical piping portion 2c by the gas phase pressure gauge 4a of the vertical piping portion 2c, and the pressure of the liquid phase X1 by the liquid phase pressure gauge 4b. Measure The liquid level calculation unit 4 calculates the liquid level based on the pressure value of the gas phase X2, the pressure value of the liquid phase X1, and the density of the liquefied natural gas X supplied from the LNG tanker 100 given in advance by the calculation unit 4c. Calculate the

  The density acquisition unit 5 also measures the pressure of the liquid phase X1 between the first pressure gauge 5a and the second pressure gauge 5b. And the density acquisition part 5 is the distance in the perpendicular direction of the pressure value which the density calculation part 5c was measured by the 1st pressure gauge 5a and the 2nd pressure gauge 5b, and the 1st pressure gauge 5a and the 2nd pressure gauge 5b. And the density of liquid phase X1 is calculated. Further, the liquid level correction unit 6 corrects the liquid level height acquired from the liquid level calculation unit 4 based on the density calculated by the density acquisition unit 5.

  Subsequently, the liquid level adjustment unit 7 obtains the liquid level height corrected by the control unit 7c from the liquid level correction unit 6, and if the liquid level height is lower than a predetermined value, the pump 7a Is driven to open the adjusting valve 7b. Thereby, the liquid phase X1 stored in the storage tank 3 flows into the vertical piping portion 2c, and the liquid level of the vertical piping portion 2c rises. The liquid level adjustment unit 7 stops the pump 7a and closes the adjustment valve 7b when the control unit 7c sets the liquid level of the liquid phase X1 in the vertical piping unit 2c to a predetermined height.

  In the receiving facility 1 of the present embodiment, the density acquisition unit 5 acquires the density of the liquid phase X1, and the liquid level correction unit 6 corrects the liquid level based on the acquired density. Thereby, the error based on the density distribution included in the liquid level height calculated by the liquid level calculation unit 4 can be eliminated, and the correct liquid level height in the vertical piping portion 2c can be acquired. Therefore, the liquid level in the vertical piping portion 2c can be appropriately adjusted, and the receiving piping 2 can be properly cooled.

  Further, in the receiving facility 1 of the present embodiment, the density acquisition unit 5 calculates the differential pressure in the vertical direction in the vertical piping portion 2c, thereby calculating the density of the liquid phase X1 in the vertical piping portion 2c. Therefore, the density of the liquid phase in the vertical piping portion 2c can be acquired by attaching a pressure gauge to the existing vertical piping portion 2c, so it is easy to acquire the density of the liquid phase.

  Further, in the receiving facility 1 of the present embodiment, the liquid level adjustment unit 7 adjusts the liquid level height of the liquid phase X1 in the vertical piping unit 2 c based on the liquid level height corrected by the liquid level correction unit 6. Can. Thus, the receiving pipe 2 can be properly cooled based on the correct liquid level.

  As mentioned above, although the suitable embodiment of the present invention was described referring to drawings, the present invention is not limited to the above-mentioned embodiment. The shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

  In the above embodiment, the liquid level calculation unit 4 has a gas pressure gauge 4a and a liquid pressure gauge 4b, and the density acquisition unit 5 has a first pressure gauge 5a and a second pressure gauge 5b. The present invention is not limited to this. It is good also as what is provided with the combined pressure gauge which combines the liquid phase pressure gauge 4b and the 2nd pressure gauge 5b. In this case, in this case, the calculation unit 4c acquires a pressure value from the dual-use pressure gauge. Similarly, the density calculation unit 5c acquires a pressure value from the dual-use pressure gauge. Since the number of pressure gauges installed in the vertical piping portion 2c can be reduced, mounting becomes easier.

  Moreover, in the said embodiment, although the density acquisition part 5 employ | adopted the structure which calculates a density by calculating the difference of the pressure of a different position in a perpendicular direction, this invention is not limited to this. The density acquisition unit 5 can also be a Coriolis-type densitometer.

  The density acquisition unit 5 can also use a differential pressure gauge. In this case, similarly to the density acquisition unit 5 of the above embodiment, the density calculation unit 5c that calculates the density from the differential pressure is included.

1 receiving facility 2 receiving piping 2a receiving main pipe 2b receiving branch pipe 2c vertical piping section 2d valve 3 storage tank 3a concrete 3b tank section 4 liquid level calculation section 4a gas phase pressure gauge 4b liquid phase pressure gauge 4c calculation section 5 density acquisition section 5a First pressure gauge 5b Second pressure gauge 5c Density calculation unit 6 Liquid level correction unit 7 Liquid level adjustment unit 7a Pump 7b Adjustment valve 7c Control unit 100 Tanker

Claims (5)

A liquefied gas receiving facility comprising receiving piping connected to a tank for storing liquefied gas, comprising:
Liquid level calculation means for calculating the liquid level of the liquefied gas inside the receiving pipe;
Density acquisition means for acquiring the density of the liquid phase of the liquefied gas stored in the receiving pipe;
And a liquid level correction unit that corrects the liquid level based on the density of the liquefied gas acquired by the density acquisition unit.   The liquefied gas receiving facility according to claim 1, wherein the density acquisition unit calculates the density based on a differential pressure of a liquid phase of the liquefied gas. The density acquisition unit
A first pressure gauge for measuring the pressure of the liquid phase of the liquefied gas;
A second pressure gauge provided at a position different from the first pressure gauge in the vertical direction and measuring the pressure of the liquid phase of the liquefied gas;
The liquefied gas receiving facility according to claim 2, further comprising: a density calculation unit that calculates the density of the liquefied gas based on the pressure of the liquid phase acquired from the first pressure gauge and the second pressure gauge. The liquid level calculation means includes a gas phase pressure gauge that measures the pressure of the gas phase inside the receiving pipe, and a liquid phase pressure gauge that measures the pressure of the liquid phase of the liquefied gas,
The liquefied gas receiving facility according to claim 3, wherein the liquid pressure gauge is also used as the first pressure gauge or the second pressure gauge. The liquid level adjusting means is provided to adjust the liquid level based on the liquid level corrected by the liquid level correcting means.
The liquid level adjusting means is connected to the receiving pipe to adjust a flow amount of the liquefied gas into the receiving pipe, and the liquid level height corrected by the liquid level correcting means is acquired. The liquefied gas receiving facility according to any one of claims 1 to 4, further comprising: a control unit that adjusts a liquid level of the receiving pipe by opening and closing a valve.

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