JP2011226911A - Composition analysis method of hydrocarbon composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition analysis method of a new hydrocarbon composition.SOLUTION: A gas chromatography analysis is performed for a saturated hydrocarbon composition containing at least a linear saturated hydrocarbon and a cyclic saturated hydrocarbon, and in the resulting gas chromatogram, one or two or more local minimal points are selected from a plurality of local minimal points that exist in the region between a peak assigned to the linear saturated hydrocarbon having carbon atoms of n and a peak assigned to the cyclic saturated hydrocarbon carbon atoms of n-1 for each carbon number of the linear saturated hydrocarbon. And, the content ratio of the cyclic saturated hydrocarbon to the saturated hydrocarbon composition is calculated based on the formula (1). C=S/S×100 (1) [Crepresents the content ratio of the cyclic saturated hydrocarbon, Srepresents the total peak area in the gas chromatogram, Srepresents the area of the closed region formed by a line segment which connects all of the chosen local minimal points and a baseline of the gas chromatogram.]

Description

  The present invention relates to a composition analysis method for a hydrocarbon composition.

  Conventionally, mineral base materials have been widely used as base materials for petroleum products such as fuel oils such as gasoline, kerosene and light oil, and lubricating oils. A mineral oil-based base material is a hydrocarbon composition obtained by distilling crude oil and further subjecting it to purification treatment such as hydrogenation treatment, if necessary, usually a mixture of saturated, olefinic, aromatics, etc. It is. Further, the saturated component can be further classified into a linear saturated hydrocarbon, a branched saturated hydrocarbon and a cyclic saturated hydrocarbon. The content ratio of the above-described components in the hydrocarbon composition is an important factor that determines the characteristics of the mineral oil base material in various applications.

  As a method of composition analysis of saturated components in hydrocarbon compositions heavier than gasoline, linear saturated carbonization is performed by performing gas chromatography analysis on the saturated components separated from the hydrocarbon composition by silica gel chromatography or the like. It is common among those skilled in the art to quantitate cyclic saturated hydrocarbons by carrying out mass spectrometry of hydrogen and to calculate the content of branched saturated hydrocarbons from the results. In addition, as a method for quantifying cyclic saturated hydrocarbons, a method for obtaining by mass spectrometry is known (see, for example, Non-Patent Document 1), but linear saturated hydrocarbons, cyclic saturated hydrocarbons, and branched chains. There is no known method for quantifying gaseous saturated hydrocarbons using the same analytical means.

ASTM D 425 “Standard Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry”

  An object of the present invention is to provide a novel composition analysis method for a hydrocarbon composition, which can easily and accurately quantify a cyclic saturated hydrocarbon contained in a hydrocarbon composition.

The present invention includes a first step of performing a gas chromatography analysis on a saturated hydrocarbon composition containing at least a linear saturated hydrocarbon and a cyclic saturated hydrocarbon to obtain a gas chromatogram;
In the gas chromatogram obtained in the first step, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a linear carbon atom having n-1 carbon atoms. One or two or more minimum points are selected from a plurality of minimum points existing in the region between the peaks attributed to hydrogen, and cyclic saturated hydrocarbons occupying the saturated hydrocarbon composition based on the following formula (1) A second step of calculating the content ratio of
A composition analysis method for a hydrocarbon composition comprising:
C _N = S _N / S _A × 100 (1)
[Wherein C _N represents the content (unit: mass%) of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _N represents the second step. The area of the closed region formed by the line segment connecting all the selected minimum points and the baseline of the gas chromatogram is shown. ]

  In addition, since the cyclic saturated hydrocarbon contained in the hydrocarbon composition can be quantified more accurately, the minimum point selected in the second step is a peak attributed to the linear saturated hydrocarbon having n carbon atoms. Among a plurality of minimum points existing between the peaks attributed to the linear hydrocarbon having n-1 carbon atoms, the minimum point giving the minimum value and the minimum point giving the second smallest value in the region It is preferable that it is two or more minimum points containing.

  Furthermore, since the simplicity and accuracy in quantifying the cyclic saturated hydrocarbon contained in the hydrocarbon composition can be achieved at a high level, the minimum point selected in the second step is linear saturation with n carbon atoms. Among a plurality of minimum points existing in a region between a peak attributed to a hydrocarbon and a peak attributed to a linear hydrocarbon having a carbon number of n-1, a minimum point giving a minimum value in the region and 2 The minimum point giving the second smallest value is preferable.

Moreover, the composition analysis method of the hydrocarbon composition of the present invention provides a peak attributed to the linear saturated hydrocarbon for each carbon number of the linear saturated hydrocarbon in the chromatogram obtained in the first step. Further, a third step of selecting the two minimum points existing at the closest positions on both sides and calculating the content of the linear saturated hydrocarbon in the saturated hydrocarbon composition based on the following formula (2) It is preferable to provide.
C _L = S _L / S _A × 100 (2)
[Wherein, C _L represents the content (unit: mass%) of linear saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _L represents the third The area of the closed region formed by the line segment connecting the two minimum points selected in the above step and the peak curve attributed to the linear saturated hydrocarbon having n carbon atoms is defined as the linear saturated hydrocarbon The total value for the total carbon number is shown. ]

Furthermore, the composition analysis method of the hydrocarbon composition of the present invention further includes a fourth step of calculating the content of the branched saturated hydrocarbon in the saturated hydrocarbon product based on the following formula (3). It is preferable to provide.
C _B = 100− (C _N + C _L ) (3)
Wherein, C _B is the content of the branched-chain saturated hydrocarbon among the saturated hydrocarbon composition: shows the (unit weight%), C _N is the proportion of cyclic saturated hydrocarbon among the saturated hydrocarbon composition ( unit: wt%) indicates, C _L is the content of linear saturated hydrocarbons among the saturated hydrocarbon composition (unit: shows the mass%). ]

  In the conventional composition analysis method, linear saturated hydrocarbons are obtained by performing gas chromatography analysis on the saturated fractions separated from the hydrocarbon composition by silica gel chromatography or the like, and cyclic by mass analysis. The operation was complicated and the analysis took a long time, such as quantifying each saturated hydrocarbon and calculating the content of the branched saturated hydrocarbon from the results. On the other hand, in the present invention, all of linear saturated hydrocarbons, branched saturated hydrocarbons and cyclic saturated hydrocarbons are obtained by using only gas chromatography analysis through the first to fourth steps. Since the content ratio can be calculated with high accuracy, it is very useful in terms of easy operation and shortening of analysis time.

  As described above, according to the present invention, there is provided a novel hydrocarbon composition composition analysis method capable of easily and accurately quantifying a cyclic saturated hydrocarbon contained in a hydrocarbon composition.

It is a figure which shows an example of the gas chromatogram obtained when a gas chromatographic analysis is performed on said analysis conditions about the saturated part fractionated from the mineral oil type | system | group light oil base material. In the gas chromatogram shown in FIG. 1, a plurality of peaks existing in a region between a peak attributed to a linear saturated hydrocarbon having n carbon atoms and a peak attributed to a linear hydrocarbon having n−1 carbon atoms are present. It is a figure which shows the state when selecting the minimum point which gives the minimum value in the said area | region from the minimum point, and the minimum point which gives the 2nd smallest value, and connecting all the selected minimum points. It is the figure which expanded partially the area | region containing the peak attributed to a C14-C19 linear saturated hydrocarbon of the gas chromatogram shown in FIG. It is a graph which shows the result of the composition analysis in Example 1 and Comparative Example 1.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  In the composition analysis method for a hydrocarbon composition according to the present embodiment, first, gas chromatographic analysis is performed on a saturated hydrocarbon composition containing at least a linear saturated hydrocarbon and a cyclic saturated hydrocarbon to obtain a gas chromatogram. (First step).

  The saturated hydrocarbon composition as a sample is not particularly limited as long as it contains at least a linear saturated hydrocarbon and a cyclic saturated hydrocarbon. For example, a saturated component fractionated from a mineral oil base material used in petroleum products such as fuel oil such as gasoline, kerosene and light oil, and lubricating oil can be used as a sample. Examples of means for separating a saturated component from a mineral oil base material include silica gel chromatography and high performance liquid chromatography (HPLC). The carbon number range of the saturated hydrocarbon composition used as the sample is preferably 7 to 32, more preferably 8 to 31, and still more preferably 9 to 30.

Analysis conditions in the gas chromatography analysis are appropriately selected according to the type of measurement sample, carbon number distribution, and the like. An example of analysis conditions in the case where the sample is a saturated fraction fractionated from a mineral oil-based light oil base material is shown below.
Device: GC2010 (manufactured by Shimadzu Corporation) (gas chromatograph with FID (Frame Ionization Detector))
Column: Ultra Alloy-HT (30 m × 0.25 mmφ × 0.15 μm) or nonpolar columns HP-1, CBP-1, etc. Carrier gas: Helium Carrier gas pressure: 120 kPa
Inlet temperature: 300 ° C
Detector temperature: 300 ° C
Oven temperature: 50 ° C (5 minutes) to 300 ° C (5 minutes)
Injection volume: 2 μL (a hexane solution with a purity of 99% by volume or more obtained by HPLC)
Split ratio: 1/10.

  Needless to say, the gas chromatographic analysis is preferably carried out after confirming that the baseline is stable after FID ignition.

The gas chromatogram can be obtained as a graph (GC chart) in which the horizontal axis represents retention time (retention time) and the vertical axis represents peak intensity. FIG. 1 shows an example of a gas chromatogram obtained when a gas chromatographic analysis is performed under the above-described analysis conditions for a saturated fraction collected from a mineral oil-based light oil base material. Area of closed area formed with the baseline peak curve (curve giving the peak) in FIG. 1 corresponds to a total peak area S _A in later-described formula (1) and (2).

Next, in the obtained gas chromatogram, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a linear hydrocarbon having n-1 carbon atoms are obtained. The inclusion of cyclic saturated hydrocarbons in the saturated hydrocarbon composition based on the following formula (1) by selecting one or more minimum points from a plurality of minimum points existing in the region between the assigned peaks The ratio is calculated (second step).
C _N = S _N / S _A × 100 (1)
[Wherein C _N represents the content (unit: mass%) of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _N represents the second step. The area of the closed region formed by the line segment connecting all the selected minimum points and the baseline of the gas chromatogram is shown. ]

  Here, since the cyclic saturated hydrocarbon contained in the hydrocarbon composition can be quantified more accurately, the minimum point selected in the second step is a peak attributed to the linear saturated hydrocarbon having n carbon atoms. Among a plurality of minimum points existing in a region between the peak and the peak attributed to the straight-chain hydrocarbon having n-1 carbon atoms, a minimum point giving the minimum value and a minimum giving the second smallest value in the region Two or more local minimum points including the point are preferable.

  Furthermore, since the simplicity and accuracy in quantifying the cyclic saturated hydrocarbon contained in the hydrocarbon composition can be achieved at a high level, the minimum point selected in the second step is linear saturation with n carbon atoms. Among a plurality of minimum points existing in a region between a peak attributed to a hydrocarbon and a peak attributed to a linear hydrocarbon having a carbon number of n-1, a minimum point giving a minimum value in the region and 2 The minimum point giving the second smallest value is preferable.

FIG. 2 is a diagram illustrating an example of a gas chromatogram after the second step. FIG. 2 shows a peak attributed to a linear saturated hydrocarbon having n carbon atoms and a linear chain having a carbon number of n−1 for each carbon number of the linear saturated hydrocarbon in the gas chromatogram shown in FIG. From the multiple minimum points existing in the region between the peaks attributed to hydrocarbons, select the minimum point giving the minimum value and the minimum point giving the second smallest value in the region, and all the selected minimum points It shows the state when linking. The shaded portion in FIG. 2 is a closed region formed by the line segment connecting the selected minimum points and the baseline of the gas chromatogram, and this area corresponds to S _N in equation (1).

  Moreover, FIG. 3 is the figure which expanded partially the area | region containing the peak attributed to a C14-C19 linear saturated hydrocarbon of the gas chromatogram shown in FIG. FIG. 3 shows, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a peak attributed to the linear hydrocarbon having n−1 carbon atoms. 2 shows two local minimum points selected from a plurality of local minimum points existing in a region between and a line segment connecting the selected local minimum points.

Moreover, in the chromatogram obtained in the first step, the hydrocarbon composition analysis method according to the present embodiment is attributed to the linear saturated hydrocarbon for each carbon number of the linear saturated hydrocarbon. Third step of selecting the two minimum points existing at the closest positions on both sides of the peak and calculating the content of the linear saturated hydrocarbon in the saturated hydrocarbon composition based on the following formula (2) Alternatively, it is preferable that the method further includes a fourth step of calculating the content ratio of the branched chain saturated hydrocarbon in the saturated hydrocarbon product based on the following formula (3). By passing through the first to fourth steps, only the gas chromatographic analysis is used to accurately calculate all the content ratios of the linear saturated hydrocarbon, the branched saturated hydrocarbon and the cyclic saturated hydrocarbon. Therefore, it is very useful in terms of easy operation and shortening of analysis time.
C _L = S _L / S _A × 100 (2)
[Wherein, C _L represents the content (unit: mass%) of linear saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _L represents the third The area of the closed region formed by the line segment connecting the two minimum points selected in the above step and the peak curve attributed to the linear saturated hydrocarbon having n carbon atoms is defined as the linear saturated hydrocarbon The total value for the total carbon number is shown. ]
C _B = 100− (C _N + C _L ) (3)
Wherein, C _B is the content of the branched-chain saturated hydrocarbon among the saturated hydrocarbon composition: shows the (unit weight%), C _N is the proportion of cyclic saturated hydrocarbon among the saturated hydrocarbon composition ( unit: wt%) indicates, C _L is the content of linear saturated hydrocarbons among the saturated hydrocarbon composition (unit: shows the mass%). ]

In addition, this invention is not restrict | limited to said embodiment at all. For example, advance to obtain the correlation between C _N and S _N by the content of pre-cyclic saturated hydrocarbon perform first and second steps for a plurality of saturated hydrocarbon composition is known (calibration curve), it may be calculated C _N from the measured values S _N based on the correlation. Similarly, a correlation (calibration curve) between C _L and S _L is obtained by performing the third step on a plurality of saturated hydrocarbon compositions in which the content ratio of the linear saturated hydrocarbon is known in advance, As may be calculated C _L from measured values S _L based on the correlation. Furthermore, to obtain data on density of cyclic saturated hydrocarbons and linear saturated hydrocarbons contained in the saturated hydrocarbon composition, C _N and C _L, or be further converted into mass percentage of C _B from percentages by volume it can.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Example 1]
Three types of saturated components (samples A, B, and C) separated from fuel oils A, B, and C having different compositions by HPLC were used as samples, and composition analysis of the saturated components was performed according to the following procedure.
First, each sample was subjected to gas chromatography analysis to obtain a gas chromatogram. The analysis conditions in the gas chromatography analysis are shown below.
Device: GC2010 (manufactured by Shimadzu Corporation) (gas chromatograph with FID (Frame Ionization Detector))
Column: Ultra Alloy-HT (30 m × 0.25 mmφ × 0.15 μm) Carrier gas: Helium carrier gas pressure: 120 kPa
Inlet temperature: 300 ° C
Detector temperature: 300 ° C
Oven temperature: 50 ° C (5 minutes) to 300 ° C (5 minutes)
Injection volume: 2 μL (a hexane solution with a purity of 99% by volume or more obtained by HPLC)
Split ratio: 1/10.

  Next, in the obtained gas chromatogram, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a linear hydrocarbon having n-1 carbon atoms are obtained. From a plurality of local minimum points existing in the region between the assigned peaks, a local minimum point that gives the minimum value and a local minimum point that gives the second smallest value in the region are selected, and based on the above formula (1), The content ratio of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition was calculated.

  Furthermore, in the obtained chromatogram, for each carbon number of the linear saturated hydrocarbon, select two local minimum points existing on both sides of the peak attributed to the linear saturated hydrocarbon, Based on Formula (2), the content rate of the linear saturated hydrocarbon which occupies for a saturated hydrocarbon composition was computed. Moreover, the content rate of the branched saturated hydrocarbon which occupies for a hydrocarbon saturated product was computed based on the said Formula (3). The time required for the analysis (the sum of the gas chromatography measurement time and the identification time) was 3 hours.

[Comparative Example 1]
Samples A, B, and C used in Example 1 were quantitatively analyzed for linear saturated hydrocarbons by performing gas chromatography analysis, and cyclic saturated hydrocarbons by performing mass spectrometry. The content ratio of the branched saturated hydrocarbon was calculated. The gas chromatography analysis is the same as that of Example 1 except that the injection amount is changed to 0.3 μL and the split ratio is changed to 1/70. On the other hand, the analysis conditions of mass spectrometry are as follows.
Ionization method: FI (Field Ionization)
Mass separation method: Double focusing magnetic field type vacuum degree: 10 ⁻⁶ Torr
Resolution: 500 or more Ion detection: Positive scanning mass range: 40 to 400 m / z
Accelerating voltage: 3.0 kV
Emitter current: 5 mA
Sample introduction method: DI (Direct Probe)
DI temperature rise conditions:
Initial temperature: normal temperature (holding time 0 minutes)
Temperature rising rate: 32 ° C / min Final temperature: 400 ° C (holding time 20 minutes)
Injection volume: 1.0 μL (saturated fraction fractionated by silica gel chromatography)

  The results of the composition analysis obtained in Example 1 and Comparative Example 1 are shown in FIG.

  As shown in FIG. 4, in Example 1, all the proportions of linear saturated hydrocarbons, branched saturated hydrocarbons and cyclic saturated hydrocarbons are accurately calculated using only gas chromatography analysis. Confirmed that you can. Further, in Example 1, the analysis time is 3 hours, which is significantly shorter than that of the conventional method of Comparative Example 1, and linear saturated hydrocarbons, branched saturated hydrocarbons and cyclic saturated hydrocarbons are analyzed by the composition analysis method of the present invention. It turns out that everything can be analyzed quickly.

[Example 2]
First, a gas chromatographic analysis was performed on Sample A in the same manner as in Example 1. Next, in the obtained gas chromatogram, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a linear hydrocarbon having the carbon number n-1 are attributed. Only a minimum point that gives the minimum value in the region is selected from a plurality of minimum points existing in the region between the peak and the cyclic saturated carbonization occupied in the saturated hydrocarbon composition based on the above formula (1). The hydrogen content was calculated. The analysis time was 3 hours.

[Example 3]
First, a gas chromatographic analysis was performed on Sample A in the same manner as in Example 1. Next, in the obtained gas chromatogram, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a linear hydrocarbon having the carbon number n-1 are attributed. A plurality of local minimum points existing in the region between the peak to be selected, a local minimum point that gives the minimum value in the region, a local minimum point that gives the second smallest value, and a local minimum point that gives the third smallest value, Based on the above formula (1), the content ratio of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition was calculated. The analysis time was 3 hours.

  Table 1 shows the results of the composition analysis of Sample A obtained in Examples 1 to 3 and Comparative Example 1. The analysis time shown in Table 1 is the sum of measurement time and identification time.

  As shown in Table 1, also in Examples 2 and 3, it was confirmed that all the content ratios of linear saturated hydrocarbon, branched saturated hydrocarbon and cyclic saturated hydrocarbon can be calculated with high accuracy. It was. Furthermore, in Example 1 in which the minimum points selected for each carbon number of the linear saturated hydrocarbon were 2 points and in Example 3 which was 3 points, quantification could be performed with higher accuracy.

Industrial application fields

The composition analysis method of the hydrocarbon composition of the present invention is, for example, in the field of petroleum products such as gasoline, kerosene and light oil, and petroleum products such as lubricating oil, cyclic saturated hydrocarbons contained in the hydrocarbon composition, or more linear. It is useful as a method for quantifying saturated hydrocarbons and branched chain saturated hydrocarbons.

Claims (5)

A first step of performing a gas chromatography analysis on a saturated hydrocarbon composition containing at least a linear saturated hydrocarbon and a cyclic saturated hydrocarbon to obtain a gas chromatogram;
In the gas chromatogram, for each carbon number of the linear saturated hydrocarbon, a peak attributed to the linear saturated hydrocarbon having n carbon atoms and a peak attributed to the linear hydrocarbon having n-1 carbon atoms. 1 or 2 or more minimum points are selected from a plurality of minimum points existing in the region between and based on the following formula (1), the content ratio of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition is A second step of calculating;
A composition analysis method for a hydrocarbon composition comprising:
C _N = S _N / S _A × 100 (1)
[Wherein C _N represents the content (unit: mass%) of the cyclic saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _N represents the second The area of the closed region formed by the line segment connecting all the minimum points selected in the step and the baseline of the gas chromatogram is shown. ]   The minimum point selected in the second step is in a region between a peak attributed to a linear saturated hydrocarbon having n carbon atoms and a peak attributed to a linear hydrocarbon having n-1 carbon atoms. The method according to claim 1, wherein among a plurality of existing local minimum points, there are two or more local minimum points including a local minimum point that gives a minimum value in the region and a local minimum point that gives a second smallest value.   The minimum point selected in the second step is in a region between a peak attributed to a linear saturated hydrocarbon having n carbon atoms and a peak attributed to a linear hydrocarbon having n-1 carbon atoms. The method according to claim 1, wherein among the plurality of existing local minimum points, the local minimum point that gives the minimum value in the region and the local minimum point that gives the second smallest value. In the chromatogram, for each carbon number of the linear saturated hydrocarbon, two local minimum points existing on both sides of the peak attributed to the linear saturated hydrocarbon are selected, and the following formula (2 ), The method according to any one of claims 1 to 3, further comprising a third step of calculating a content ratio of the linear saturated hydrocarbon in the saturated hydrocarbon composition.
C _L = S _L / S _A × 100 (2)
[Wherein C _L represents the content (unit: mass%) of the linear saturated hydrocarbon in the saturated hydrocarbon composition, S _A represents the total peak area in the gas chromatogram, and S _L represents The area of the closed region formed by the line segment connecting the two minimum points selected in the third step and the peak curve attributed to the straight chain saturated hydrocarbon having n carbon atoms is defined as the straight chain. The total value of the total number of carbon atoms of the saturated hydrocarbon is shown. ] 5. The method according to claim 1, further comprising a fourth step of calculating a content ratio of the branched chain saturated hydrocarbon in the saturated hydrocarbon product based on the following formula (3). Method.
C _B = 100− (C _N + C _L ) (3)
[Wherein, C _B is the branched saturated content of hydrocarbons accounts for the saturated hydrocarbon composition (unit: mass%) indicates, the cyclic saturated hydrocarbon C _N is occupied in the saturated hydrocarbon composition the proportion (unit: mass%) indicates, C _L is the proportion of the straight-chain saturated hydrocarbon occupied in the saturated hydrocarbon composition: shows the (unit weight%). ]

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