Higher-Temperature Simulated Distillation with DB-HT Sim Dis Columns

Significance of Topic

The accurate characterization of heavy petroleum fractions is essential for refining operations, quality control and detection of feedstock adulteration. High-temperature simulated distillation (HTSD) extends traditional simulated distillation methods to boiling points above 1000 °F, enabling comprehensive profiling of heavy crude oils and residua. By pushing gas chromatographic systems to 430 °C or higher, refiners obtain detailed boiling-point distributions from the lightest hydrocarbons through C110 and beyond, supporting yield optimization and process troubleshooting.

Objectives and Study Overview

This application report introduces a robust metal GC column, DB-HT Sim Dis, designed for HTSD analyses up to 430 °C. The study outlines method parameters, column construction and performance benchmarks versus competitor columns. Key goals include validating extended boiling-point range coverage, demonstrating column inertness and durability under rigorous temperature cycling, and illustrating typical chromatographic profiles for standard n-paraffin mixtures and reference crude oils.

Methodology and Instrumentation

Methodology

• Analyses follow ASTM D6352 guidelines for HTSD of petroleum distillates up to 700 °C.
• Thin-film capillary GC SimDist uses 5 m × 0.53 mm id columns with 0.15 µm film thickness of 100 % dimethylpolysiloxane.
• Programmable temperature vaporization (PTV) injection of 0.5 µL n-paraffin standards or crude oil dilutions (~2 % in CS2) minimizes discrimination.
• Helium carrier flow of 18 mL/min; oven ramp from –30 °C to 430 °C at 10 °C/min; final hold of 5 min.
• Detection by flame ionization (FID) at 450 °C with nitrogen makeup gas.

Instrumental Features

• DB-HT Sim Dis is constructed from deactivated stainless-steel tubing, enabling operation to 430 °C without brittleness.
• Proprietary polymer bonding and crosslinking yield low bleed and inert surfaces critical for quantitative accuracy at high temperatures.
• Column part number: J&W 145-1001.

Main Results and Discussion

Range and Resolution

• Effective simulated distillation from C5 through C110 (AEBP from approximately 70 °C to 735 °C) with a single column.
• Linear boiling-point versus retention-time calibration demonstrated by standard n-paraffin series up to C110.

Durability

• Users report over 400 temperature cycles (–30 °C to 430 °C) with negligible retention loss or peak deformation.
• Compared to a competitor metal column, DB-HT Sim Dis maintained sharp peak shapes and baseline resolution after 377 cycles, outlasting the competitor by 35 %.

Crude Oil Profiling

• SimDist chromatograms of midrange and full-range reference crudes exhibit clear baseline returns at final boiling points, confirming column efficacy for heavy fractions.

Benefits and Practical Applications

• Accurate boiling-point distribution data support refinery yield optimization and vacuum tower operation.
• High inertness and low bleed ensure reliability for QA/QC laboratories analyzing heavy feeds and finished products.
• Extended upper temperature tolerance enables detection of high-boiling adulterants and complete profiling of residua.

Future Trends and Application Possibilities

Advances in column deactivation and stationary phase chemistry will further improve inertness at extreme temperatures. Integration of HTSD with mass spectrometric detectors could enhance component identification within heavy fractions. Automation of HTSD workflows, including online sample dilution and PTV injection, promises increased throughput. Emerging catalysts and process monitoring needs will drive broader use of HTSD in bio-based fuels and polymer recycling applications.

Conclusion

The DB-HT Sim Dis metal column delivers superior performance for high-temperature simulated distillation up to 430 °C, offering extended boiling-point range coverage, excellent inertness and outstanding thermal durability. Its robustness under aggressive temperature cycling and low bleed profile make it an ideal choice for ASTM D6352 compliance and demanding petroleum analysis tasks.

Reference

1. D.C. Villalanti, D. Janson and P. Colle, Hydrocarbon Characterization by High Temperature Simulated Distillation (HTSD), AIChE Spring Meeting Distillation Session, March 1995.
2. ASTM D2887, D3710 and D6352, ASTM International, West Conshohocken, PA.
3. A.K. Vickers, M. Hastings, D. Rood and R. Lautamo, An Improved Deactivation Process for Metal Tubing Used in Capillary Gas Chromatographic Columns, Pittsburgh Conference and Exposition, March 1995.