Fast and Accurate Analysis of Refinery Gas using Multi Channel Micro Gas Chromatography

Importance of the Topic

The composition of refinery gas streams varies with feedstock and process conditions, making rapid and precise analysis essential. Accurate quantification of hydrocarbons, permanent gases and contaminants supports process optimization, product quality control and compliance with safety and environmental regulations.

Objectives and Study Overview

This work assesses the Agilent 490 Multi-Channel Micro Gas Chromatograph for fast, reliable refinery gas analysis. Key aims include:

• Achieving total analysis times below three minutes for C1–C10 components
• Simultaneous separation of permanent gases, light hydrocarbons and heavier fractions
• Demonstrating column protection and speed improvements using backflush technology

Methodology

The Agilent 490 Micro GC was configured with four independent channels, each featuring micro-machined injectors and μTCD detectors. Stationary phases and conditions:

• Molecular Sieve 5A for permanent gases (H2, O2, N2, CO, CH4)
• PoraPLOT U for C2 hydrocarbons, CO2 and H2S
• Alumina oxide for C3–C5 saturated and unsaturated hydrocarbons
• Non-polar CP-Sil 5 for C6+ hydrocarbons

Isothermal operation (70–150 °C) and controlled carrier gas pressures (helium or argon) were maintained. Backflush routines on selected channels prevented late-eluting compounds from contaminating analytical columns. Agilent OpenLAB CDS EZChrom managed data acquisition and reporting.

Instrumentation

• Agilent 490 Micro GC with up to four independently controlled channels
• Electronic carrier gas control and micro thermal conductivity detectors
• Backflush configuration to extend column life and reduce analysis time

Key Results and Discussion

• Baseline separation and identification of 34 components within approximately 150 seconds
• Effective resolution of permanent gases, C2–C5 fractions and C6–C10 hydrocarbons
• Backflush functionality shortened cycle times and protected stationary phases from moisture and heavy hydrocarbons
• Integrated reporting yielded normalized mole percentages and BTU values in accordance with ASTM, GPA and ISO standards

Benefits and Practical Applications

Rapid multi-channel micro GC offers:

• High-throughput QA/QC for refinery operations
• On-site and real-time monitoring for gas processing, biogas and fuel cell research
• Automated compliance with official analytical methods and integrated reporting

Future Trends and Opportunities

• Further miniaturization and portable systems for remote or field applications
• Integration with mass spectrometry or advanced detectors for enhanced selectivity
• Automation with real-time data analytics for predictive process control
• Expansion into renewable gas and complex biofuel analysis

Conclusion

The Agilent 490 Micro GC demonstrates rapid, accurate and comprehensive refinery gas analysis. Its multi-channel design, coupled with backflush technology and integrated software, delivers reliable quantification in under three minutes, supporting routine QA/QC and real-time process monitoring.

References

1. SI-02233; Application Note – Fast Refinery Gas Analysis Using the 490 Micro GC QUAD; Agilent Technologies; 2010
2. 5990-6664EN; Brochure – Agilent 490 Micro GC; Agilent Technologies; 2010