Analysis of Boiling Point Distributions in Petroleum Fractions using Simulated Distillation (ASTM D2887A)

Importance of the Topic

Simulated distillation by gas chromatography provides rapid and precise boiling range distribution of petroleum fractions with boiling points up to 538 °C, offering a safer and more efficient alternative to traditional physical distillation methods.

Objectives and Study Overview

This application note demonstrates the use of ASTM D2887 procedure A using a SCION SimDist GC-FID system to determine boiling point distributions of petroleum feedstocks and fractions from 36 °C to 545 °C. The method aims to validate performance against consensus reference values and highlight advantages over conventional techniques.

Methodology and Instrumentation

A SCION 456-GC or 436-GC configured with a cool-on-column injector, SCION SimDist 10 m × 0.53 mm × 2.65 µm column, helium carrier gas (20 mL/min), and flame ionisation detector at 350 °C was used. The oven was programmed from –20 °C to 350 °C at 10 °C/min with a 2 min hold. Calibration employed a C5–C44 n-paraffin mixture (1 % wt each in CS2) to establish the retention time versus boiling point relationship. Samples were diluted in CS2 according to ASTM D2882-18 and analysed in quintuplicate for a reference gas oil.

Main Results and Discussion

Calibration yielded a linear correlation between retention time and boiling point across the entire C5–C44 range. Analysis of a reference gas oil over five injections produced boiling point cuts at 5 % increments with differences from consensus ASTM values generally below 2 °C. The initial boiling point and cuts at 5 %, 10 %, and up to 95 % weight recovery agreed closely with reference data. The final boiling point showed a larger deviation (7.5 °C) but remained within the allowable limit of the method.

Benefits and Practical Applications

• High precision and repeatability for boiling range distribution.
• Lower sample volume and reduced hands-on time compared to TBP distillation.
• Faster throughput and cost efficiency for QA/QC in refineries and laboratories.
• Enhanced safety due to smaller sample sizes and closed-column injection.

Future Trends and Potential Applications

Advances in high-temperature GC columns and detectors may extend the upper boiling point range beyond 545 °C. Integration with automated sample handling and machine learning for peak deconvolution could further improve speed and accuracy. Broader adoption in petrochemical process control and environmental monitoring is anticipated.

Conclusion

The SCION SimDist solution meets ASTM D2887 procedure A criteria, delivering boiling range distributions equivalent to true boiling point distillation and suitable for routine petroleum analysis. Observed deviations from reference values were minimal, confirming the reliability of simulated distillation for product specification and refining control.

References

ASTM D2887 18 Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography