JPS61196161A - Gas chromatograph anlysis apparatus and method - Google Patents

Abstract

PURPOSE:To achieve a higher separability and a shorter analysis, by dividing a first column into upstream and downstream columns while a six-way passage change-over cock is provided to connect the inlet sides of upstream and downstream columns to the output sides thereof respectively. CONSTITUTION:A mixed sample introduced 5 reaches a six-way passage change- over cock 17 by a carrier gas and enters a column 61 via passages 17-1 and 17-2 to undergo a separation. In this process, after a certain time passes, the component groups quicker to elute with a less holding time passes through passages 17-3 and 17-6 and reaches a column 62. But in this period, the component groups slow to elute with a larger holding time remains in the column 61. When the passage is turned as indicated by the broken line by the operation of the cock 17 at the optimum timing, the components in the column 62 pass through passages 17-5 and 17-2 to be introduced to the column 61 again, where is separated completely. Thus, the components elute with columns 9 and 10 sequentially from those quicker to elute with the smallest holding time at the final passage 17-4 through a rear changeover cock 8 after the changeover of the subsequent cock 17 to be detected 13 with a convergence section 11 and a resistance column 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, an LNG carrier cargo tank or an LNG carrier cargo tank.
The present invention relates to a gas chromatograph analyzer and method for analyzing mixed gases and general samples (including liquid samples and gas samples) containing a plurality of components in a process of replacing inerting gas with natural gas in NG onshore storage tanks, etc. That is, the present invention can be applied to, for example, LNG tankers or LN tankers.
After the construction of the underground tank is completed, the air inside the tank is replaced with an inert gas (inert gas, 85% of which is inert gas).

Following the inerting work performed to replace the inert gas with gaseous natural gas (Co, 15%), composition and concentration analysis of the gaseous natural gas was conducted to monitor the replacement process in the tank. The present invention relates to a gas chromatograph analyzer and an analysis method that can improve separation and shorten analysis time when using a gas chromatograph.

[Conventional technology]

FIG. 2 shows a diagram of a conventional gas flow chart.

For example, after inerting work is completed on a tank of an LNG carrier, etc., the tank is replaced with natural gas, and after the inside of the tank is almost completely replaced with natural gas, the tank is cooled and replaced with r, NG (liquefied natural gas). ] is required.

In the above process, when filling the tank with natural gas after the inerting operation and replacing it with inert gas, it is necessary to constantly monitor the inert gas in the tank and the replacement ratio of natural gas at short intervals. In this case, inert gas components (Nh about 85%, Co and about 15%) and natural gas components (CF14Fe2O290%, O, H
, 5-10 Chi, 0sHs 5-5 To, nC4T11
The concentration of each component was determined by gas chromatography analysis of a mixed gas with α, 5 to 196). However, in this case, it is impossible to completely separate the above components using a single separation column, and separation and analysis are generally performed by configuring a column flow path as shown in Figure 2, which combines two to three columns. Is going. To explain the conventional column flow path configuration and analysis method with reference to FIG. 2, in the tJIE2 diagram, 1 is the inlet of the carrier gas, where the carrier gas is divided into an analysis side flow path and a target lI flow path. 2,1
4 is a pressure reducer for flow rate adjustment on the analysis side and the target side, respectively.
3.15 is the pressure gauge of each carrier gas flow path. 4 is a carrier gas branch provided on the analysis side, 5 is a gas sample introduction device, 6 is a first separation column, and 7 is a resistance column having the same length and the same flow path resistance as 6 (usually the same product as 6). ] 18 is a four-way flow path switching cock, 9 is a $2 separation column, 10 is a second separation column with the same flow path resistance as 9 and has no separation adsorption properties, 11 is a second separation column. The confluence of the flow path of the separation column 9 and the flow path from the resistance column 10, 12 is the column 9 when the four-way flow path switching hook 8 is operated.
A resistance column 13 is a dual type detector having two flow paths, one on the analysis side and the other on the object side. 16 is a resistance column on the target flow path side.

The separation column 6 is a cycolumn containing a packing material that can separate the hydrocarbons, which are the components of the natural gas, in the order of i''LL boiling points, and also separate CO!.
Length 2m filled with filler manufactured by Co., Ltd., trade name: VZ-TOY
For example, when the above-mentioned mixed gas is analyzed using a column with an inner diameter of 5 rv'mφ, the eluted components are N2 + 01
14, O,H・・CO,・0MHm * 1'4”
Separation column 9 is usually filled with silica gel, etc., and is equivalent to the above.Filling material from Gascro Kogyo Co., Ltd.Product name: Unib
I am using eads 8. The flow path [6→(8-4)→(
8-5) → 9], the component group of N and +OH4, which cannot be completely separated in column 6, becomes N! and 0111. Completely separate. Of course, the subsequent CIH-~n04H1• has no problem in separation, but since the retention time in column 9 is long, the elution time becomes longer and the peak shape of the chromatogram becomes broader.

To explain the flow path only on the analysis side in the gas chromatograph analysis means configured as shown in FIG. Road (8-4),
[81) and reaches column 9. The carrier gas divided through the branch section 4 passes through the column 7 and is then transferred to the flow path switching cock 8.
It reaches the column 10 through the channels (8-2) and (8-1), merges with the channel from the analysis-side separation column 9 at the confluence section 11, passes through the entire resistance column 12, and reaches the column 10 for analysis in the precipitator 15. reach the side. Note that if no shock occurs in the baseline of the chromatogram by operating the column switching cock 8, a good chromatogram can be obtained without installing the column 12.

When the gas sample introducing device 5 is operated to introduce a mixed gas sample into the analysis side of the prepared gas chromatograph analyzer shown in FIG. 6, and while passing through this column 6, it is separated into component groups, and at the outlet of column 6, in the elution order, (a) Nl + CH4, (b) C, H, (
C) Co, ,) O, H, (e) jC, Hl., (f) n○4H10 components are eluted from the column in this order. The chromatogram at this time is shown in FIG. Carrier gas flow path t - If the solid line in FIG.

(8-5) After Th, it enters column 9, but H2+ of (a)
(!When the H4 group is delayed to column 9 and the retention time is long and the elution is slow (b) and the subsequent groups are on the upstream side of the switch cock 8, operate the switch cock 8 and make the change as shown by the broken line. (b) Subsequent components and carrier gas pass through the flow paths (8-4) and (8-1) of cock 8 to the column 1.
Also, in the group (A) in column 9, the carrier gas from column 7 flows through the broken line flow path (8-2) of switching cock 8.
, (8-1) to column 9. Separation continues, (
b) Complete separation of groups occurs. On the other hand, the groups after (b) pass through the column 10 in the same order without being subjected to the same effect in the column 10, and reach the confluence section 11.
It merges with the flow path from the column 9, passes through the resistance column 12, and reaches the detector 15, where the separated components are detected. The detection unit records the electrical signal on chart paper or connects it to an integrator to calculate the concentration. column 9, column 1
By appropriately selecting the length of 0, the flow rate, and the switching timing of the column switching cock 8, the mixed gas mentioned in the example can be changed to N2 e ClI4 e C24e CO2e C3T
ll * 1-'4H1°.

It can be completely separated and analyzed in the order n-C4H10.

[Problem that the invention seeks to solve]

Even with the conventional gas chromatography analysis method using the above-mentioned narrow column flow path, analysis can be performed within about 18 minutes, as shown in Figure 4. requires a gas chromatograph analyzer and analysis method that can analyze most of the composition components in a shorter time.

An object of the present invention is to provide a gas chromatograph analyzer and an analysis method that can analyze the composition and concentration in as short a time as possible when monitoring the entire tank gas replacement process described above.

In addition, the present invention can be used as a general-purpose type rather than a special structure, and is small and lightweight so that it can be easily installed in a ship, inside a ship, or in a field management room, and furthermore, it is capable of automated analysis. It is also an object of the present invention to provide a gas chromatograph analyzer.

[Means for solving problems]

That is, the present invention includes a Wc1 separation column in the sample flow path,
In a gas chromatograph analyzer in which a flow path switching cock and a second separation column are arranged in order, the first separation column is separated into an upstream column and a downstream column, and a flow path is provided, and the upstream column is This gas chromatograph analyzer is characterized in that it is provided with hexagonal channel switching hooks that connect the inlet and outlet sides of the downstream column and the inlet and outlet sides of the downstream column, respectively.

Furthermore, the second invention of the present invention is to separate the Wj, 1 separation column Gold R @ column and the downstream column, and provide a flow path, and to connect the inlet and outlet sides of the upstream column and the downstream column. In a gas chromatograph analysis method that analyzes mixed components using a gas chromatograph analyzer equipped with a hexagonal flow path switching cock that connects the inlet side and the outlet side respectively, some of the mixed components elute due to a short retention time. Components that take a long time and have poor separability are passed through the hexagonal flow path switching cock in the order of upstream column, downstream column, and upstream column, and then passed through the hexagonal flow path switching cock to the second separation column. On the other hand, among the mixed components, components with long retention times, slow elution times, and good separation are passed through only the upstream column via the six-way flow switching cock, and then the six-way flow switching is performed. This is a gas chromatography analysis method that aims to improve separation performance and shorten analysis time by allowing the flow through a different kind of column on the downstream side through a cock.

The present invention is carried out in the middle of column 6 in FIG. 2 (column 6).
A general-purpose gas chromatograph apparatus can be used as is by simply providing a hexagonal flow path switching cock between the two sections (divided into appropriate proportions). In addition, components that elute from the column and elute slowly with long retention times generally have good separation, but tend to have broad peak shapes. Because it is connected to a column or detector, the peaks are sharp. On the other hand, components that elute from the column and elute quickly due to their short retention time are determined by the length of the column when no channel switching cock is provided midway, and by the cock switching operation (column length according to the present invention). If a flow path switching cock is provided at position 172, analysis can be performed using a column length that is 1A added to the initial column length.To summarize the above, in the present invention, a constant length In the separation column, a flow path switching cock can be provided in the middle of the separation column to change the flow path order of the divided columns.

Therefore, in the present invention, the length of the separation column can be increased or decreased to the length required for complete separation of the components to be separated, thereby achieving complete separation and shortening of analysis time. .

〔Example〕

tlIi1 Figure is a flow path configuration diagram showing an embodiment of the present invention.
2 is a diagram showing an improvement in the flow path configuration from the gas sample/introducing device 5 to the four-way flow path switching cock 8 shown in FIG. 2. FIG. In FIG. 1, 17 is a hexagonal passage switching cock provided for the present invention, (17-1), (17-2]... (17-6) are each flow of the hexagonal passage switching cock 17. 61.62 is the same type as column 6 in Figure 2, and is a column with a length of 1/2 (in the following explanation of the function), and 61 → (17-5) → (1
7-6) When I62 and the flow path are configured, column 6 in Figure 2
It has the same length and the same ability of separation action. The hexagonal flow path switching cock 17 and subsequent steps reach the flow path switching cock 8 in Fig. 2, but this Fig. 1 is not limited to improvements only around the column 6 in Fig. The cock part can also be regarded as a detection part and interpreted as an improvement to the column flow path configuration of a normal gas chromatograph.

Next, the entire analysis means according to the present invention will be explained based on FIG. For ease of explanation, a case will be described in which a hexagonal flow path switching cock 17 is provided at a position 1/2 the length of the column 6 in FIG. 2.

In FIG. 1, the mixed sample introduced from the gas sample introduction device
leading to the flow path (17-1).

(17-2) After passing through column 61, it is subjected to separation action, but as time passes and the retention time is small, it dissolves tB.
/'(I)N," CHa, (C') C*Ha,
(c) Co, O component glue 1 is hexagonal flow path switching cock 1
7, the solid line channels (17-5) and (17-6) lead to the sicolumn 62. At this time, the retention time is long and the elution is slow) CI"m s (e) i-04H1+>- (e)
n-04H1 (1 component group is still in column 61. At such an optimal time, the hexagonal flow channel cock 17t-
If you operate and trap the flow path as shown by the broken line in Figure 1, column 6
(a) N+OH4, (b) C! H-1(
c) The Co component is the channel (1) of the hexagonal channel switching cock 17.
7-5), (17,-2] and then led again to column 61) to be completely separated. Besides, (i)N! +CTi
Component 4 has a short retention time and elution is quick, so it is still subjected to the separation action in the column 61 before the hexagonal channel switching cock 17 is operated, and of course remains in the column 61 even after switching)
C*”ms(e)1-C4H1(1%(e)n-”4H
Elution is faster than each of the 10 components, and hexagonal flow path switching cock 17
The order of component elution from the final channel (17-4) is first (
b) N1 + OH4, then separated only by column 61)'1H1s, then (ff) N1+ C+) Same as I4] H1-04"l with long separation and slow elution with a long retention time
Os (he) overtakes and elutes n-C4H16 (mouth)
C2H@, and (c)CO, elute, and finally H1-
OaHlo and (to) n-C! 4H1(1) elutes. Also, (a) the N2 + CH4 peak is completely separated into N2 and OH4 in the latter column 9 as described above. This chromatogram is shown in Figure 5. component) CsHs s (e) 1-C4H10s (e)
For analysis of n-C4H10, 1/2 of the column length in Figure 2 is sufficient, and component (a) N1+ (:!H4, (o)
C2H@, G'l COx u, column 61 in Figure 1
yf! : It will pass twice and column 62t once,
With the same equipment length and sb, 11/ of column 6 in Figure 2
The ability to utilize twice the length allows for more complete separation. However, in this example, the peak,
(b) O 11h (c) CO, and at the peak) O, H
- It is necessary to appropriately select the operating time of the channel switching cock, the carrier gas flow rate, the dividing point of the column where the channel switching cock is installed, etc., keeping in mind that the elution order is reversed.

The above-mentioned mixed sample analysis takes about 18 minutes using the conventional analysis method that utilizes the column flow path configuration shown in FIG. (If the mixed sample is analyzed by connecting two columns of the same length, column 6 and column 9 in the 'IC2 diagram, in series without the configuration of a flow path switching cock, it will take about 40 minutes and (The peak shape becomes broad.) In the present invention, as shown in Fig. 3, analysis time is possible within 9 minutes of 172 in the case of Fig. 2. The analysis time can be further shortened by appropriately selecting the installation position] and operating conditions.Furthermore, in the present invention, the switching operation and timing of the sample introduction device 5 and the hexagonal flow path switching cock 17 are controlled by the detector. The analysis can be easily automated by inputting the signal output to a data processor and controlling it from the calculation results.

The present invention is mainly aimed at mixed gases in the process of replacing inerting gas with natural gas in, for example, LNG carrier cargo tanks and LNG land storage tanks. The present invention is not limited to compositional samples, and can be applied to all kinds of mixed, gas, and liquid samples that can be analyzed by gas chromatography.

〔Effect of the invention〕

As described in detail above, the present invention provides a gas chromatograph analyzer equipped with a hexagonal flow path switching cock, and an analysis device in which the flow path of a component to be analyzed is switched through the hexagonal flow path switching cock. Since it is a method, it has the effect of improving separation performance and shortening analysis time.

[Brief explanation of drawings]

Figure 1 is a flow path configuration diagram showing an embodiment of the present invention.
The figure is a diagram showing a conventional gas chromatograph flow path configuration. H3
The figure shows a gas chromatogram according to an embodiment of the present invention, and FIG. 4 shows a gas chromatogram according to a conventional means. Sub-agents 1) Meifuku agent Ryo Hagiwara -

Claims (1)

[Claims] 1. In a gas chromatograph analyzer in which a first separation column, a flow path switching cock, and a second separation column are arranged in order in a sample flow path, the first separation column is an upstream column. Separate flow paths are provided in the downstream column, and hexagonal flow path switching cocks are provided to connect the inlet and outlet sides of the upstream column and the inlet and outlet sides of the downstream column, respectively. A gas chromatograph analyzer characterized by: 2. Separating the first separation column into an upstream column and a downstream column and providing a flow path, and connecting the inlet and outlet sides of the upstream column and the inlet and outlet sides of the downstream column, respectively. In a gas chromatography analysis method in which mixed components are analyzed using a gas chromatography analyzer equipped with a hexagonal flow path switching cock, components with short retention times, fast elution times, and poor separability among mixed components are After flowing through the upstream column, downstream column, and upstream column in this order through the flow path switching cock, the mixture components are passed through the hexagonal flow path switching cock to the second separation column. Components with long retention times, slow elution times, and good separation are passed through only the upstream column via the hexagonal flow switching cock, and then flowed through the hexagonal flow switching cock to the downstream dissimilar column. A gas chromatography analysis method that uses flow to improve separation and shorten analysis time.