Fast Analysis of Natural Gas Using the Agilent 990 Micro GC Natural Gas Analyzer

Significance of the Topic

Accurate and rapid determination of natural gas composition is essential for energy trading, process safety and regulatory compliance. Fast and reliable analysis supports correct calorific value calculation and helps detect contaminants such as carbon dioxide, hydrogen sulfide and moisture, ensuring safe transport and efficient use of this critical energy resource.

Objectives and Overview

This work evaluates four natural gas analyzer configurations based on the Agilent 990 Micro GC platform. Each configuration is tailored to a specific set of target compounds, from light permanent gases and methane to heavier hydrocarbons up to C12 and trace hydrogen sulfide. The study aims to demonstrate high‐speed separation without sacrificing resolution and to validate method performance under factory‐optimized conditions.

Methodology and Instrumentation

The multi‐channel Micro GC approach splits the sample into separate flow paths, each using a dedicated column chemistry and backflush option when needed. Key components include HayeSep A and CP‐Sil 5CB columns for hydrocarbons, CP‐PoraPLOT U for hydrogen sulfide and light hydrocarbons, and CP‐Molesieve 5Å for permanent gases. Carrier gas is helium or argon. Backflush modules protect columns by ejecting heavy or active compounds to the vent, enabling fast run times. Calibration employed simulated natural gas standards with known concentrations of C1 to C12 hydrocarbons, CO2, air and permanent gases. Chromatograms are captured by a thermal conductivity detector with precise pneumatic and thermal control.

Main Results and Discussion

• Analyzer A resolved air, methane, CO2 and C2 to C6 hydrocarbons within two minutes and extended to C9 in approximately five minutes.
• Analyzer A Extended added a third channel for rapid analysis of C6 to C12 hydrocarbons under high temperature at 150 °C, maintaining high resolution and total run time under five minutes.
• Analyzer B combined CP‐PoraPLOT U and CP‐Sil 5CB channels to quantify air, methane, CO2, H2S and C1 to C9 hydrocarbons in less than two minutes.
• Analyzer B Extended incorporated a CP‐Molesieve 5Å channel with retention time stability option, achieving baseline separation of helium, neon, hydrogen, oxygen, nitrogen and methane at ambient temperature.
• Retention time repeatability was better than 0.1% RSD and area repeatability fell below 2% RSD across ten injections, confirming robust quantitation.

Benefits and Practical Applications

The Agilent 990 Micro GC analyzers deliver high throughput, low carrier gas consumption and minimal footprint. They support in‐lab, at‐line and field deployment and can generate real‐time quality data for gas trading, pipeline monitoring and process control. The modular design allows selection of channels to match sample composition and analytical requirements.

Future Trends and Opportunities

Emerging digital integration and advanced data analytics will further enhance method automation and remote monitoring. Future developments may include miniaturized detectors, expanded volatile organic compound detection and machine learning algorithms for anomaly detection. Broader application fields include biogas analysis, hydrogen blending and carbon capture monitoring.

Conclusion

This study demonstrates that the Agilent 990 Micro GC platform offers fast, accurate and reproducible analysis of natural gas mixtures across a wide range of compounds. The multi‐channel design and backflush options enable customizable configurations that meet diverse analytical challenges in energy, industrial and environmental settings.

Reference

• Fast Analysis of Natural Gas using the Agilent 490 Micro GC Natural Gas Analyzer, Agilent Technologies Application Note 5991-0275EN, 2011.