Analysis of Fischer-Tropsch Syngas and Tail Gas with the Agilent 990 Micro GC

Importance of the Topic

Fischer–Tropsch synthesis converts syngas derived from natural gas, coal or biomass into valuable hydrocarbon liquids and solids. Real-time analysis of syngas and tail gas composition is crucial for process control, catalyst health monitoring and minimizing environmental impact.

Goals and Study Overview

This study evaluates the Agilent 990 Micro GC for rapid qualification and quantitation of permanent gases (H2, N2, CO, CO2) and light hydrocarbons (C1–C8) in Fischer–Tropsch syngas and tail gas. Two configurations, a four-channel and a more economical three-channel setup, were tested to match different compositional requirements.

Methodology and Instrumentation

The four-channel configuration used:

• 10 m CP-Molesieve 5Å with 3 m precolumn (backflush) for permanent gases
• 10 m CP-PoraPLOT U (backflush) for CO2, ethane and ethylene
• 10 m CP-Al2O3/KCl (backflush) for C3–C5 isomer separation
• 8 m CP-Sil 5CB (straight) for C6–C8 hydrocarbons

The three-channel variant replaced CP-PoraPLOT U with CP-PoraPLOT Q and removed the Al2O3 column. Each channel featured independent temperature and pressure control, argon or helium carrier gas and sub-second injection times to simplify optimization compared to conventional GC.

Main Results and Discussion

Analysis was completed in under 4 minutes. In the four-channel mode, retention time repeatability was better than 0.25 %RSD and peak area RSD below 1 % for all target analytes. The Al2O3 channel resolved C3–C5 alkene and alkane isomers, while the CP-Sil 5CB channel separated α-alkenes and n-alkanes up to C8. The three-channel approach maintained similar precision for permanent gases and C1–C8 hydrocarbons at reduced cost and complexity.

Benefits and Practical Applications

• Rapid process gas monitoring to optimize catalyst performance
• Enhanced tail gas treatment and recycling strategies
• Reduced analysis time compared to benchtop GC
• Simplified method setup suitable for QA/QC in petrochemical plants

Future Trends and Opportunities

• Integration of micro GC data with advanced process analytics and machine learning
• Extension to heavier hydrocarbon fractions and oxygenates
• Further miniaturization and field-deployable versions for on-site monitoring
• Real-time feedback loops for adaptive process control

Conclusion

The Agilent 990 Micro GC delivers fast, precise and reproducible analysis of Fischer–Tropsch syngas and tail gas components in under 4 minutes. Its modular channel design and ease of operation make it a valuable tool for industrial process monitoring and research applications.

References

1. Bu LK, Xin DW, Chang SP, Lian YC Rapid Determination of Permanent Gas, C1 ~ C9 Olefins and Alkanes in Fischer Tropsch Synthesis Gas by GC. Chemical Industry Management 2021.