Rapid analysis of heavy oil catalytic cracking products using pyrolysis GC (1) Rapid evaluation of catalytic cracking of long-chain hydrocarbons (C16-C56)

Significance of the Topic

Heavy oil catalytic cracking is central to refining processes aiming to convert large hydrocarbon molecules into valuable lighter fractions. Rapid evaluation methods are essential to optimize catalyst efficiency and refine product yield in industrial settings.

Objectives and Study Overview

This study investigates the effect of varying catalyst-to-oil ratios on the cracking of long-chain hydrocarbons (C16–C56) using a pyrolysis GC/FID system. It aims to establish a fast analytical approach to assess conversion efficiency with minimal sample preparation.

Instrumentation Used

• Multi-Shot Pyrolyzer (EGA/PY-3030D, Frontier Labs) directly interfaced to GC injector
• Gas chromatograph with FID detector
• UA-SIMDIS(HT) capillary column (5 m × 0.53 mm, df = 0.1 µm)

Methodology

Sample cups containing calibrated amounts of equilibrium catalyst and heavy oil dissolved in toluene were prepared at mixing ratios from 3:1 to 23:1 (catalyst:oil). Toluene was evaporated, and cups were subjected to pyrolysis at 500 °C. Volatile products were transferred via helium carrier gas to the GC inlet held at 340 °C. The oven program ramped from 60 to 400 °C at 20 °C/min with a 3 min hold. Detector temperature was maintained at 400 °C.

Key Results and Discussion

Chromatograms showed that higher catalyst ratios promote breakdown of C16–C56 compounds into lower boiling fractions. Three carbon number zones (C16–20, C21–30, C31–56) were quantified. Cracking efficiency plateaus beyond an 18:1 ratio, indicating optimal catalyst loading for maximum conversion.

Benefits and Practical Applications

• Rapid screening of catalyst performance in refinery QA/QC
• Minimal sample preparation and solvent use
• High-throughput evaluation enabling process optimization

Future Trends and Potential Applications

Further integration with mass spectrometry could enhance molecular-level insights. Automation of sample handling and data analysis may support real-time process monitoring. Adaptation to bio-oil and alternative feedstocks presents opportunities for sustainable refining.

Conclusion

This pyrolysis GC/FID approach offers a robust fast method to evaluate heavy oil cracking performance. Optimal catalyst-to-oil ratios above 18:1 yield efficient conversion, supporting refined process controls in industrial applications.

References

No additional literature sources were listed.