INTRODUCTION

SCION Instruments offers the solution for a simulated distillation of middle distillates and lubricating base oils.

EN15199-1 specifies a standardized method for the determination of boiling range distribution of middle distillates and lubricating base oils by gas chromatography, with initial boiling points (IBP) of at least 100°C and final boiling points (FBP) of below 750°C (C₁₂₀).

Simulated gas chromatography distillations can be used as a reference method for  conventional distillation methods which can provide a quantitively percent mass yield as a function of the boiling point for hydrocarbon components in the sample. The boiling point distribution is a routinely used parameter to monitor and improve the production process and quality of refinery products. Simulated distillations are a safer and faster way than conventional distillations to perform a similar boiling range distribution of distillates.

This SIMDIST application is applicable on the SCION Instruments 8X00 GC-platform, shown in figure 1, with the 8400PRO autosampler.

Figure 1. SCION Instruments 8X00 GC platform equipped with the 8400PRO autosampler.

RESULTS AND DISCUSSION

The SCION SIMDIST analyzer used for this application, is equipped with a SCION Instruments 8X00-GC who’s configured with a temperature programmable cold on column (COC) injector with air cooling, a SCION-Simdist column and a high temperature Flame Ionization Detector (FID) with ceramic HT flame tip. The analyzer uses a 8400PRO autosampler for excellent repeatability results, used in Standard On-Column mode.

Note that method EN15199-1 is not applicable  for the analysis of petroleum or petroleum products containing low molecular weight components, such as naphtha’s, reformates, gasolines and diesels. For the determination of heavy distillates and residuals fuels method EN15199-part 2 is recommended. For the analysis of crude oils method EN15199-part 3 is recommended.

Table 1 is showing the analytical conditions of the SCION Instruments GC system.Reference oil 5010 1%

A reference oil with known initial boiling point and final boiling point is injected to validate the method and system. See figure 2 and table 2 for the results and specifications of the reference oil. In figure 2, point 1 is the start of elution time, point 2 the initial boiling point (IBP) and point 3 is the final boiling point (FBP). Point 4 is the end of elution of the sample and where the septum purge is opened for cleaning the system. The results in table 2 show that all the targets of the critical points are easily achieved.

Table 2. Results Reference oil 5010 1%

Figure 2. Chromatogram Reference Oil 5010 1%

Repeatability (R) is determined by measuring the reference oil 5010 1% in duplicate. The difference (Δ) between the 2 generated boiling point distributions is calculated and compared with the set specification mentioned in EN15199-1. According to table 3 the system can easily achieve good repeatability results within specifications.

Table 3. Repeatability (R) results

A calibration mixture of normal paraffins covering the range from C₅ up to C₁₂₀ dissolved in CS₂ was used to determine the relationship of boiling point (BP) versus retention times (RT).

See figure 3 for the chromatogram of the calibration standard and figure 4 for the retention time vs. boiling point of the calibration standard.   

A gravimetric blend is analysed for checking the relative response of the two distillates and to check the baselines at the start, middle and end of the chromatogram.  Figure 5 shows the chromatogram of analysis of the gravimetric blend, where a baseline separation is shown between the two fractions. Figure 6 is showing the boiling point curve vs. mass % of the gravimetric blend.

Figure 3. Chromatogram Calibration mix

Figure 4. Retention time (RT) vs. boiling point

Figure 5. Chromatogram Gravimetric Blend

Figure 6. Boiling point curve of the Gravimetric Blend 

According to the results shown in table 4 the system and method are performing brilliantly within the specifications mentioned in EN15199-1.

Table 4. System performance results 

Figure 7 is showing a chromatogram using the Compass Eclipse software plug in, with combined Retention time vs boiling point curve. The software makes it possible to easily obtain the boiling range distribution with different standardized methods, shown in the right handed column of the figure.

Figure 7. Chromatogram calibration mix using the Compass Eclipse software plug in, and other optional methods.

CONCLUSION

The SCION Instruments  8X00 GC-platform provides a robust and complete solution for the simulated distillation of distillates and lubricating base oils, following standardized method EN15199-1. The obtained results demonstrate that this method and the SCION Instruments GC system configuration performs excellent and meets all the specifications mentioned in EN15199-1.

The equipment of the 8X00-GC analyzer is pre determined, for ordering information or customisation please contact your local sales representative.

Although the 4X6-GC series is not shown in this application note, it is also possible to perform this method on the SCION instruments 4X6 GC series.

Download the Application Note

Download our full Application Note: EN15199-1 Determination of Boiling Range Distribution by Gas Chromatography Method Part 1: Middle Distillates and Lubricating Base Oils

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