JPH01277756A - Analyzing method of fuel of petroleum system and apparatus therefor - Google Patents

Abstract

PURPOSE:To simplify an operation for analysis of a fuel of a petroleum system, by separating and detecting aromatics in a sample by using a reversed-phase column and a gel filtrating column for a stationary phase and by using a mixed solution containing an ethyl alcohol etc. for a mobile phase. CONSTITUTION:A first column 1 for analysis separates paraffin, aromatics, naphthene and olefin in a sample by using a silica gel column for a stationary phase, and a mixed solution of n-hexane and an isopropyl alcohol for a mobile phase. The separated aromatics is detected by an ultraviolet absorption detector 5, while a part of it is accumulated in a trap tube 16. Then, the aromatics accumulated in this trap is separated by using a reversed-phase column 9 and a gel filtrating column 10 for a stationary phase and an ethyl alcohol, a methyl alcohol and chloroform accommodated in a tank 2, for a mobile phase. The separated aromatics is detected by the aforesaid ultraviolet detector 6.

Description

[Detailed Description of the Invention] (Technical Field) The present invention analyzes paraffins, olefins, naphthenes, aromatic tylaus, and aromatic nucus cyclic bodies contained in petroleum fuels such as gasoline and kerosene. Focus on technology.

(Prior art) When evaluating the quality of petroleum-based fuels, such as their combustibility, it is important to check the content ratios of paraffins, olefins, naphthenes, and aromatics that make up these components, as well as the cyclic structure that makes up the aromatics. It is carried out based on the ratio of the body's components. For such analysis, a gas chromatograph or a high-performance liquid chromatograph is usually used. In the former, the target components of analysis, such as paraffins, olefins, aromatics, etc., are separated into discrete components and detected. Therefore, there is a problem that it is time-consuming because it requires the work of integrating the analysis results and converting them into the ratio of the target component.
Also, according to the criminals, paraffins, olefins, naphthenes,
While it is possible to detect aromatic laurel as a single peak, it is not possible to detect the cyclic bodies contained in aromatics as a component, so it is necessary to analyze aromatic bamboo separately under different analysis conditions. However, the problem was that analysis work required time and effort.

(Purpose) The present invention was made in view of these problems, and its purpose is to be able to detect each component necessary for quality evaluation as a single peak through one sample injection. An object of the present invention is to provide a petroleum fuel analysis device using a high-performance liquid chromatograph.

Another object of the present invention is to propose a method for separating and detecting aromatex rings.

(Summary of the Invention) V That is, the present invention is characterized by using a silica gel column as a stationary phase and a mixture of n-hexane and isoprobil alcohol as a mobile phase to analyze paraffin, aromatics, A process of separating naphrene and olefin, a process of detecting the aromatics by ultraviolet absorption and accumulating a part of them, and transferring the aromatics accumulated in this process to a stationary phase using a reverse phase column and a gel filtration column. , and also realizes a separation and detection process using ethyl alcohol, methyl alcohol, and chloroform as mobile phases.

(Example) The details of the present invention will be described below based on illustrated examples.

FIG. 1 shows an example of an apparatus used in the present invention, in which reference numeral 1 is a first analytical column for high-performance liquid chromatography using silica gel as a stationary phase, and one end is connected through a sample injection port 2. to the mobile phase tank 3, and the other end or the first
The flow path switching valve 4 is also connected. 4 is the aforementioned first flow path switching valve, which connects the first column to the detection flow path 7 consisting of the ultraviolet absorbance detector 5 and the refractometer 6, and the second analysis column 8 to be described later to the detection flow path 7. The pipes are connected as shown. 8 is the aforementioned second analysis column for high performance liquid chromatography, and on the inflow side, that is, on the side of the second flow path switching valve 11 (described later), an octadecyl group is chemically bonded to the polymer base to form a hydrophobic interaction. A gel filtration column 10 is connected in series on the outflow side, that is, on the side of the first flow path switching valve 4. A pipe connection is made to selectively connect to the second mobile phase tank 12 and the trap pipe 13.

11 is the aforementioned second flow path switching valve, which when set to the first position connects the flow path to the second mobile phase tank 12, the second analysis column 8, and the ultraviolet absorption detector in the detection flow path. 5 and the refractometer 6, through the branch pipe 14, the flow coefficient is adjusted by the resistance pipe 15, and flows into the trap pipe] 6. When set to the second position, the second Mobile phase liquid tank 12, trap tube 16, second analytical column 8
The pipes are connected to form a flow path leading to the pipe. In addition,
In the figure, reference numerals 17 and 18 indicate pumps for feeding the mobile phase, and 19 indicates an outlet.

Next, the operation of the apparatus configured as described above will be explained.

A first mobile phase consisting of a mixture of n-hexadi and Improv alcohol was placed in the first mobile phase tank 3, and a second mobile phase was placed in the first mobile phase tank 3.
A mobile phase tank] 2 contains a second mobile phase consisting of a mixture of chloroform, ethanol, methanol, and water, and a first flow path switching valve 4 is connected to the flow path shown by the solid line in the figure. When the flow path switching valve 11 of No. 2 is set to the state shown by the solid line in the figure and each pump 17, 18 is operated, the first mobile phase consisting of a mixture of n-hexane and isopropyl alcohol flows through the sample injection mechanism 2. , the first analytical column 1 , and the ultraviolet absorption detector 5 . The first mobile phase that has flowed into the branching section 14 is divided depending on the flow path resistance ratio between the resistance tube 15 and the flow path leading to the refraction detector 6.
A portion flows into the trap pipe 16, and the rest flows into the refractometer 6.
The second mobile phase flows from the reversed phase column 9 into the gel filtration column] and is discharged from the outlet 19.

In this state, when a sample diluted with n-hexane is injected into the injection mechanism 2, paraffins, aromatics, naphthenes, and olefins in the sample are separated by the first column 1, and paraffin is first is eluted and discharged into the detection channel 7. Part of the paraffin discharged together with the mobile phase flows into the trap tube 16 via the branch section 4, while the remainder flows into the refractometer 6. Then, the aromatics are separated from the first column and flow into the detection channel 7.The aromatics that have flowed in with the mobile phase are transferred to the branch section.
4 flows into the trap pipe 15 and is detected by the ultraviolet OK photodetector 5. When the aromatic peak disappears in this way, when the second flow path switching valve 1'1 is set to the second second position, the second mobile phase liquid is trapped from the mobile phase tank]2. Flowing into the tube 16, the aromatics contained in the trap tube 16 are discharged into the second analytical column 8.

On the other hand, naphthenes and olefins are continuously discharged from the first analytical column 1, flow into the ultraviolet absorption detector 5, and are detected. At the same time, in the second analytical column 8, the aromatic substances flowing from the trap tube 16 begin to be separated one by one based on the hydrophobic interaction of the column 9 and the molecular sieve action of the column 10.

When the last component, olefin, has been detected by the ultraviolet absorption detector 5, the first flow path switching valve 4 is set to the second position to establish a flow path as shown by the dotted line in the figure. and wait.

After a predetermined period of time has elapsed in this manner, the aromatic annular bodies are sequentially eluted from the second analysis column 8, flow into the detection channel 7, and are detected by the same ultraviolet absorption detector 5.

By the way, since the sample flowing here was contained in the trap tube 16, which has a very small volume, the sample expands or becomes smaller, and is detected as a sharp peak.

In this example, the inlet side of the trap pipe is
It is clear that the same effect can be achieved if the detection means 5.6 is connected between two detection means 5.6 or on the discharge side of the first column.

In addition, in this example, the same effect can be obtained by connecting a reverse phase column to the upstream side and a gel filtration column to the downstream side, or conversely, by arranging the gel filtration column to the upstream side. was confirmed.

[Example] As the first analytical column 1,
c k-CLC-3IL (K) (manufactured by Shimadzu Corporation),
In addition, the second analytical column 8 is
M-+000 (DuPont Fj), St”11m1)
aCk-PSG (both manufactured by Shimadzu Corporation), 400 mρ of n-hexane and 100 Uρ of isopropyl alcohol as the first mobile phase, and ethyl alcohol and meso as the second mobile phase. A mixture of equal amounts of teal alcohol, 10% chloroform, and 2% water was used, and the first mobile phase was mixed at a flow rate of 0.3 mρ, and the second mobile phase was mixed at a flow rate of 0.3 mρ. When the mobile phase was supplied at a flow rate of 0.7 mβ/min and the sample diluted 5 times with n-hexane was analyzed, as shown in Figure 2, paraffin P and aromatic A were analyzed. , naphrene N, and olefin O are each detected as one independent peak, and
The cyclic body constituting Aromatic A could also be detected as peaks P1, R2, and R3, which had independent volumes and weights.

By the way, when 1 of the Improv alcohol mixed in the first mobile phase is reduced to 50 uβ, the retention time of aromatics changes greatly to 2 to 3 minutes/day.
On the other hand, when the concentration was increased to 200uρ, the retention times of each component became close and the separation ability decreased.

As described above, according to the present invention, a silica gel column is used as a stationary phase and a mixture of n-hexane and isoprobil alcohol is used as a mobile phase to A step of separating naphrene and olefin;
This minute! The process of detecting the allotics and accumulating a part of them, and using a reverse phase column and a gel filtration column as the stationary phase, and using ethyl alcohol, methyl alcohol, chloroform and water as the stationary phase. Since a mixture is used as the mobile phase for detection, paraffins, aromatic compounds, naphthenes, and olefins, which are necessary for quality evaluation of petroleum fuels, can be detected as individual peaks as components. At the same time, it is possible to detect each of the cyclic substances contained in the aromatics of the same sample as individual peaks in a single sample injection process, which not only simplifies the analysis process but also allows for the detection of each component. It is possible to use the detection channel system in common by actively utilizing the difference in elution time between the two, and it is possible to simplify the channel and reduce the number of detection means.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an apparatus showing an embodiment of the present invention, and Fig. 2 is a chromatogram showing an example of analysis results using the same apparatus. 1...First analysis column 3...Mobile phase tank 4...Flow path switching valve 5...Ultraviolet absorption detector 6...Refractometer 8...Second analytical column

Claims (2)

[Claims] (1) Aromatics separated from petroleum fuels are separated using a reverse phase column and a gel filtration column as the stationary phase, and a mixture of ethyl alcohol, methyl alcohol, chloroform and water as the mobile phase. A method for analyzing petroleum-based fuels, which is characterized by detecting. (2) a first analytical column consisting of a silica gel column connected at one end to a first mobile phase supply pump via a sample injection port and at the other end to a detection channel via a first channel switching means; A second analytical column in which a reverse phase column and a gel filtration column are connected in series, the inflow side of the second analytical column is switched to a second mobile phase supply pump and the trap pipe discharge side, and the inflow side of the second analytical column is switched to the trap pipe discharge side, and the trap pipe inflow a second flow path switching means for switching sides between the discharge side of the first column and the second mobile phase supply pump, and the discharge side of the trap pipe between the inlet side and the outlet side of the second analysis column; A petroleum fuel analysis device.