JP2003270103A - Method of sampling fluid in fluid supply facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out sampling without depending on manual work, even when a sampling device is not provided, in a piping or the like of low using frequency. <P>SOLUTION: The sampling devices 14, 24 are provided in lines 13, 23 for feeding LNG stored in LNG tanks 11, 21 as city gas and fuel for power generation, in an LNG supply facility 10, so as to allow component analysis by automatic sampling. A sampling device 7 is not provided in lines 16, 26 used for delivery shipment to a domestic vessel or the like, but delivery pumps 12, 22 are operated to conduct sampling by the sampling devices 14, 24. The sampling is carried out in advance, posteriorly, or in both, and a change in a midway thereof is allowed to be simulated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid sampling method in a fluid supply facility in which a fluid is stored in a storage tank and supplied according to demand.

[0002]

2. Description of the Related Art Conventionally, liquefied natural gas (hereinafter referred to as "LN
It is abbreviated as "G". ) Is an LN that is transported from the production area to an LNG base by an LNG tanker for oceangoing and installed in the seaside area.
It is stored in a storage tank at G base and supplied to customers. LNG
Large-scale uses of LNG stored at the base include city gas as a raw material and a thermal power plant as a fuel. For these large customers, L
Supply NG. Although LNG is stored in the storage tank at atmospheric pressure, the pressure is increased up to several MPa with a pump and sent to large customers. From the LNG terminal, there is also a demand destination for LNG tankers for domestic shipping and tank trucks for land transportation. LNG is sent from the storage tank to these domestic LNG tankers and tank trucks through a pipe different from the large-demand customer. The delivery pressure at this time is
It is about 1 MPa.

[0003] LNG is a mixture containing methane as a main component, and the amount of heat varies depending on the composition. Therefore, it is necessary to determine the composition when trading LNG. The composition of LNG can be examined by sampling, vaporizing and analyzing by gas chromatography. A sampling device is used to perform automatically from sampling to analysis.

[0004]

In a fluid supply system such as an LNG base, sampling devices are installed in all pipes having different pressures. However, there is a drawback in that the installation cost increases if it is installed even in a pipe that requires less frequent sampling.

In order to simplify the equipment and reduce the investment cost, there is a method in which the gas vaporized in the sampling equipment is manually collected in a collection bottle and brought back to the analysis room. Since it is done manually, there are many mistakes when collecting and setting the collection bottle for gas chromatography, and it is necessary to increase the number of samples. In addition, it takes time and effort to rely on manpower, and in the end, it will be reflected in the driving proportional cost.

An object of the present invention is to solve the above-mentioned conventional problems. Sampling can be performed without human labor even if a sampling device is not provided for a pipe or the like which is less frequently needed. A fluid sampling method is provided in a fluid supply facility.

[0007]

According to the present invention, there are provided a storage tank capable of delivering a fluid through a plurality of pipes, and a sampling device provided in a part of the plurality of pipes for automatically sampling the fluid. A method of sampling fluid in a fluid supply facility including: when the fluid is delivered to a pipe not provided with a sampling device, the fluid is also delivered from the pipe provided with the sampling device to perform sampling. And a fluid sampling method in a fluid supply facility.

According to the present invention, a fluid is delivered from a storage tank to a plurality of pipes, and in a piping system of a fluid supply facility in which a sampling device does not exist in all of the plurality of pipes, the fluid is delivered to a pipe that does not have a sampling device. In that case, the fluid is sent out from the pipe in which the sampling device is present and sampling is performed. The fluid in the storage tank is expected to be uniform, and the fluid sent from the same storage tank to the pipe with the sampling device can be regarded as the same as the fluid sent to the pipe without the sampling device. By using, it is possible to perform sampling of piping without a sampling device without human labor. It is not necessary to provide the sampling device in all the pipes, and it is possible to provide the sampling device only in the pipes that are frequently used, so that it is possible to provide a compact and convenient supply system as a whole at low cost.

In the present invention, the sampling performed by sending the fluid to the pipe provided with the sampling device is performed at least one of before and after sending the fluid to the pipe not provided with the sampling device. It is characterized in that the data obtained by performing and sampling is corrected by simulation.

According to the present invention, when a fluid is sent from a storage tank to a plurality of pipes and a sampling device is not present in all of the pipes, the fluid is sent to the pipes without the sampling device in advance. Sampling is performed by sending out the fluid from the pipe where the sampling device exists.
In addition, the data obtained by sampling is corrected by simulation. Alternatively, a simulation is used to correct data obtained by performing post-sampling instead of pre-sampling. Alternatively, instead of pre-sampling, the data is sampled both before and after, and corrected by simulation. Since the correction is performed by the simulation, it is possible to improve the sampling accuracy of the pipe without the sampling device.

Further, according to the present invention, the pipes provided with the sampling device and the pipes not provided with the sampling device have different pressures for delivering the fluid.

According to the present invention, a fluid is sent from a storage tank to a plurality of pipes at different pressures by a pump or the like, and in a pipe system in which no sampling device is present in all of the pipes, the fluid is supplied to a pipe having a pressure in which no sampling device is present. In the case of delivering the liquid, the fluid can be delivered from the pipe having the pressure in which the sampling device exists, and the sampling can be performed. Therefore, a compact and convenient supply system as a whole can be provided at low cost.

In the present invention, the fluid is liquefied natural gas, and the sampling device vaporizes the liquefied natural gas to analyze the composition.

According to the present invention, a sampling device for sampling liquefied natural gas and analyzing the composition is installed in a pipe having a high frequency of necessity, and a pipe having a high frequency of necessity is installed to a pipe having a low frequency of necessity. Sampling can be performed using the sampling device installed in. The liquefied natural gas sampling device is expensive because it is necessary to vaporize the liquefied natural gas and analyze it by gas chromatography, etc., and it is not installed in a pipe that is infrequently needed, so the supply system should be inexpensive. You can

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described based on. For example, an LNG supply facility 10 is provided in a large-scale LNG receiving terminal that receives LNG imported from abroad in an ocean tanker that is an LNG tanker for ocean voyage having a tank of 125,000 kL. In the LNG supply facility 10, L of -160 ° C
NG has a plurality of storage tanks such as LNG tank 11 and LNG
It is stored in the tank 12. Each LNG tank 11, 12
LNG stored in the tank is boosted to 5.5 MPa by the delivery pump 12 and the delivery pump 22,
Each of them passes through a line 22 and a line 23, is gasified by a vaporizer (not shown), and is used as a raw material for city gas or a fuel for power generation. A relatively high pressure of 5.5 MPa is required in order to send it to a remote place for city gas or to use it as a combined cycle fuel for power generation.

[0016] LNG is a mixture of methane, ethane, propane, butane, etc., and it is necessary to sample and grasp its properties for trading and quality control. Therefore, the sampling device 1 is provided on the downstream side of the dispensing pump 12.
4. Sampling device 24 on the downstream side of the dispensing pump 22
Are provided respectively. In the sampling devices 14 and 24, vapor is used as a heat source to vaporize a small amount of LNG. The vaporized natural gas is continuously sent to the analysis room through tubing piping for instrumentation. In the analysis room, analysis is performed by gas chromatography. Table 1 below shows examples of the compositions obtained by sampling.

[0017]

[Table 1]

Although two LNG tanks 11 and 21 are shown in FIG. 1, one LNG tank or three or more LNG tanks may be used. Further, the payout pumps 12 and 22 may be operated by, for example, only one payout pump 12 or a plurality of payout pumps 12 may be simultaneously operated.

From a large LNG base to a relatively small L
When shipping to an NG base by, for example, a 2,000-kilometer coastal ship, the transfer pump 15 and the transfer pump 25 set L
The pressure of NG is increased to 1.0 MPa, and it is sent through line 16 and line 26 so as to be loaded on the coastal vessel via a loading arm (not shown). At this time, any number of transfer pumps 15 and 25 may be operating.

LNG is held in the LNG tanks 11 and 21 at an extremely low temperature of -160 ° C. at atmospheric pressure. LNG
A heat insulating material is applied to the tanks 11 and 21, but there is some heat input. For this reason, if LNG is continuously stored, nitrogen or methane having a low boiling point vaporizes in the liquid, and the composition changes with the passage of time. In addition, the composition differs depending on the place of origin of LNG. Therefore, a plurality of LNG tanks 11 and 21
If LNG is stored in the LNG tank 11,
The composition of LNG is different for each 21.

In order to ship LNG to coastal vessels, it is necessary to understand the composition. The simplest method is to newly install the sampling device 7. However, since the sampling device for LNG is expensive, if the frequency of shipping by a coastal ship is low, the economical efficiency becomes poor.

Therefore, instead of installing the sampling device 7, LNG tanks 11 used for shipping to coastal vessels,
The delivery pumps 12 and 22 of 21 are LNG tanks 11 and
One or more units are operated for each 21 and sampling is performed by the sampling facilities 14, 24 downstream of the payout pumps 12, 22. If the composition is calculated from the compositions obtained by the sampling devices 14 and 24, no equipment cost is required.

From the sampling results of the sampling devices 14 and 24 downstream of the payout pumps 12 and 22, it is possible to calculate as shown in the following equation (1).

[0024]

[Equation 1]

Where a _i : LNG to be shipped to the coastal vessel
Component (mol%) (i = methane, ethane, ...) a _ji : LN sampled by j4 sampling facility
G component (mol%) (i = methane, ethane, ...) w _j : flow rate of LNG delivered from the j5 transfer pump (t /
h).

For example, 100 tons from the LNG tank 11
/ H, the LNG tank 21 is shipped to a coastal vessel at 200 t / h. From the components which are operated by the delivery pump 12 and sampled by the sampling device 14 and the components which are operated by the delivery pump 22 and sampled by the sampling facility 24, the components to be shipped to the coastal vessel can be obtained as shown in Table 2. In this way, LNG
When the product is shipped, the delivery pumps 12 and 22 are always operated, so that the components can be easily obtained without newly installing equipment.

[0027]

[Table 2]

In the above-mentioned example, when the LNG is shipped to the coastal ship, the payout pumps 12 and 22 are always operated at the same time. However, the payout pumps 12 and 22 are operated in advance and the sampling devices 14 and 24 are used. It is also possible to simulate from the sampled components.

As mentioned above, LNG is -16 at atmospheric pressure.
It is held in the LNG tanks 11 and 21 at 0 ° C.
A heat insulating material is applied to the LNG tanks 11 and 21, but there is some heat input. With the passage of time, nitrogen and methane, which have low boiling points in the liquid, are vaporized and the composition changes.

It has been known from the operation data so far that only nitrogen and methane having a low boiling point can be regarded as vaporized. The contents of nitrogen and methane change as shown in the following equation (2).

[0031]

[Equation 2]

Here, b _i : LNG amount after the lapse of sampling t time (mol) (i = nitrogen, methane) b _i0 : LNG amount at sampling (mol) (i = nitrogen,
Methane) c _i : coefficient determined by the type, shape, size, etc. of the LNG tank t: elapsed time (h) at the time of sampling.

Using the above formula, the dispensing pump 1
It is possible to simulate the change of the component with time from the component sampled by the sampling device 14 when the No. 2 is operated. Table 3 shows the results of simulating the compositions after 60 hours and 240 hours. Further, the graphs of FIGS. 2 and 3 show changes in the compositions of nitrogen and methane with time in the cases shown in Table 3, respectively. The solid line is obtained by simulation, and the square points are measured data. It can be seen that the simulation results accurately match the measured values.

[0034]

[Table 3]

Although the example shown in Table 3 is a simulation example of the composition after a certain time has elapsed, it is also possible to simulate the composition in advance, for example, 60 hours before, from the data after the fact. In addition, the accuracy will be further improved by calculating from both pre and post data and taking the average.

In this way, prior to shipping to coastal vessels,
Alternatively, when the delivery pump 12 is operated after the fact, by obtaining the LNG composition from the components sampled by the sampling device 14 by simulation, the components can be easily obtained without newly installing equipment.

In the above description, the LNG supply facility 1
Although a plurality of 0 piping systems are used for sampling LNG overall composition analysis, the present invention can be similarly applied to sampling for analysis of specific components such as sulfur. Further, not only LNG but also other fluid supply facilities such as crude oil can be similarly sampled.

[0038]

As described above, according to the present invention, when the fluid is delivered from the storage tank to the pipe in which the sampling device does not exist, the fluid is also delivered from the pipe in which the sampling device exists, and sampling is performed without human labor. It can be performed. It is not necessary to provide the sampling device in all the pipes, and it is possible to provide the sampling device only in the pipes that are frequently used, so that it is possible to provide a compact and convenient supply system as a whole at low cost.

Further, according to the present invention, when a fluid is sent from a storage tank to a plurality of pipes and a sampling device is not present in all of the pipes, the fluid is sent to a pipe without a sampling device in advance. After the fact, or after both, the fluid is sent from the pipe in which the sampling device is present to perform sampling, and the data obtained by the sampling is corrected by simulation. Since the correction is performed by the simulation, it is possible to improve the sampling accuracy of the pipe without the sampling device.

According to the present invention, when the fluid is delivered from the storage tank to the plurality of pipes at different pressures by a pump or the like, and the fluid is delivered to the pipe having a pressure at which the sampling device does not exist, the pressure at the sampling device Since the fluid can be sent out from the pipe to perform sampling, a compact and convenient supply system as a whole can be provided at low cost.

Further, according to the present invention, the liquefied natural gas sampling device is expensive because it is necessary to vaporize the liquefied natural gas and analyze it by gas chromatography or the like, and it is not installed in a pipe which is less frequently needed. Therefore, the supply system can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing a schematic configuration of an LNG supply facility 10 which is a target for executing a fluid sampling method according to an embodiment of the present invention.

FIG. 2 is a graph in which actual measurement results are plotted on a curve showing a simulation result of nitrogen concentration shown in Table 3.

FIG. 3 is a graph in which actual measurement results are plotted on a curve showing simulation results of methane concentration shown in Table 3.

[Explanation of symbols]

7,14,24 Sampling device 10 LNG supply equipment 11,21 LNG tank 12,22 Dispensing pump 13,16,23,26 line 15,25 Transfer pump

Continued front page    F term (reference) 2G052 AA10 AC23 AD06 AD42 CA04                       CA12 EB01 GA27 HB08 JA07                 3E073 AA01 BB00 DB03                 3J071 AA23 BB02 CC24 DD28 EE09                       EE19 EE28 FF03

Claims (4)

[Claims] 1. A fluid sampling in a fluid supply facility including a storage tank capable of delivering a fluid through a plurality of pipes, and a sampling device which is provided in a part of the plurality of pipes and automatically performs sampling of the fluid. A method for supplying fluid to a pipe not provided with a sampling device, wherein the fluid is also sent from the pipe provided with the sampling device to perform sampling. Sampling method. 2. Sampling performed by sending a fluid to a pipe provided with the sampling device is performed at least before or after sending a fluid to a pipe not provided with the sampling device, and The fluid sampling method for fluid supply equipment according to claim 1, wherein the data obtained by sampling is corrected by simulation. 3. The fluid supply equipment according to claim 1, wherein the pipe provided with the sampling device and the pipe not provided with the sampling device have different pressures for delivering a fluid. Fluid sampling method. 4. The fluid supply according to claim 1, wherein the fluid is liquefied natural gas, and the sampling device vaporizes the liquefied natural gas to analyze the composition. Fluid sampling method in equipment.