Highly Characterized Reference Standard: Pyrolysis Gasoline

Importance of the Topic

Pyrolysis gasoline is a valuable byproduct of ethylene production, serving as a feedstock for olefins, aromatics, and benzene. Reliable characterization of this complex hydrocarbon mixture is critical for process optimization, quality control, and ensuring consistent performance in downstream applications.

Objectives and Study Overview

This study aimed to develop a highly characterized, real-world reference standard for pyrolysis gasoline. Detailed qualitative and quantitative analyses were conducted using combined GC/FID and GC/MS methods to create chromatographic maps and establish accurate component profiles.

Methodology and Instrumentation

The reference standard was prepared by collecting bulk pyrolysis gasoline samples, stabilizing with 75 ppm 1,3-phenylenediamine, and packaging under nitrogen in amber ampuls. Homogeneity was verified across packaging batches before detailed analysis.

• Gas Chromatography/Flame Ionization Detection: Hewlett-Packard 5890 Series II GC; Petrocol™ DH capillary column (100 m × 0.25 mm ID, 0.5 µm film); temperature program 35 °C (10 min) to 150 °C at 1.5 °C/min, then to 280 °C at 5 °C/min; helium carrier at 48 psig; FID at 275 °C; split injection (0.1 mL) at 200 °C.
• Gas Chromatography/Mass Spectrometry: 70 eV EI; open-split interface; scan range m/z 39–200 at 1 s/scan.

Key Results and Discussion

The analysis identified key components including light olefins (butadienes, butenes), saturates (butanes, pentanes), aromatics (benzene 30–50%), and over 1% dicyclopentadiene (DCPD). Using area-percent quantitation ensured consistent comparison without reliance on pure standards. Elevated injector temperature (200 °C) minimized DCPD decomposition and improved volatilization of heavier compounds. Class separation enhanced MS identification accuracy, and coelution issues were addressed by fractionated analysis.

Benefits and Practical Applications

This reference standard supports:

• Refinery process performance evaluation
• Contamination source identification
• Development and validation of analytical methods
• PIANO analyses and operator training

Future Trends and Opportunities

Advances may include dynamic pressure programming to optimize separation, novel stationary phases for improved resolution, coupling with high-resolution MS for structural elucidation, and machine-learning algorithms for automated spectral interpretation.

Conclusion

The developed pyrolysis gasoline reference standard offers a robust tool for both qualitative and quantitative hydrocarbon analysis, enhancing reliability and comparability across laboratories.

Reference

Application Note 51, Supelco (Sigma-Aldrich Co.), 2004.