Detailed Hydrocarbon Analysis of Refinery Naphtha Streams for Determination of Compound Group-types

Significance of the Topic

The detailed characterization of refinery naphtha streams supports compliance with environmental regulations and enables optimization of gasoline blending and production processes. Detailed Hydrocarbon Analysis (DHA), often called PIONA or PIANO analysis, categorizes complex mixtures into paraffins, isoparaffins, olefins, naphthenes, and aromatics. Reliable separation of these groups is crucial for fuel performance, regulatory testing, and quality control in the petrochemical industry.

Objectives and Overview

This application note evaluates the performance of the Zebron™ ZB-DHA-PONA GC column for comprehensive PIONA analysis of refinery naphtha streams. The primary goals are to demonstrate high-resolution separation of hydrocarbon group-types, assess peak symmetry and column stability, and present alternative column dimensions for various regulatory test methods (ASTM and equivalents).

Methodology and Instrumentation

The DHA method employs capillary gas chromatography with flame ionization detection (GC-FID). Key parameters:

• Column: Zebron ZB-DHA-PONA (100 % dimethylpolysiloxane)
• Dimensions: 100 m × 0.25 mm ID × 0.50 μm film thickness
• Injection: Split ratio 40:1, inlet 300 °C, injection volume 0.2 µL
• Carrier gas: Helium at constant flow of 1.55 mL/min
• Oven program: 35 °C hold 14 min, ramp to 60 °C at 1.1 °C/min (19 min), ramp to 280 °C at 2 °C/min (5 min)
• Detector: FID at 320 °C

Additional column options (50 m, 150 m, 5 m tuning column) adapt to shorter run times, higher efficiency, or enhanced phenyl selectivity.

Main Results and Discussion

Chromatograms for paraffins, isoparaffins, olefins, naphthenes, and aromatics exhibit baseline resolution and symmetric peaks across the boiling range. The Engineered Self Cross-linking™ phase provides low bleed and exceptional column life. The combination of a deactivated fused-silica surface, robust polyimide outer layer, and 100 % dimethylpolysiloxane stationary phase ensures consistent performance, even for polar and nonpolar analytes.

Benefits and Practical Applications

• Regulatory compliance: meets EPA and international DHA/PONA method requirements
• Process optimization: detailed compositional data aids refining and blending decisions
• Quality control: robust, reproducible separations support routine laboratory workflows

Future Trends and Applications

Advancements may include coupling DHA methods with mass spectrometry for structural identification, accelerating analysis through fast-GC protocols, and integrating automated data processing with machine learning for enhanced hydrocarbon profiling. Development of eco-friendly carrier gas alternatives and micro-column formats could further reduce analysis time and resource consumption.

Conclusion

The Zebron ZB-DHA-PONA GC column offers an optimized platform for detailed hydrocarbon analysis in refinery naphtha, delivering high resolution, low bleed, and long column life. Its flexible dimension options and robust phase chemistry make it well suited for regulatory testing, process control, and research applications in the fuel industry.