Fast Analysis of Natural Gas Using the Agilent 490 Micro GC Natural Gas Analyzer

Importance of the Topic

Natural gas composition and energy content determine its commercial value, safety, and regulatory compliance. Rapid, accurate quantification of hydrocarbons, permanent gases, and trace contaminants is essential across the natural gas value chain.

Objectives and Study Overview

This application note demonstrates the capabilities of the Agilent 490 Micro GC Natural Gas Analyzer family for fast analysis of natural gas composition and heating value. Four configurations (Analyzer A, A Extended, B, B Extended) address different analysis ranges and sample matrices, suitable for laboratory, online, and field deployment.

Used Instrumentation

• Agilent 490 Micro GC Natural Gas Analyzer A – dual‐channel: HaySep A (C1–C3, CO₂) and 6 m CP-Sil 5 CB (C3–C9).
• Natural Gas Analyzer A Extended – quad‐channel adding backflush‐equipped 4 m and 8 m CP-Sil 5 CB for C3–C12 analysis.
• Natural Gas Analyzer B – dual‐channel: PoraPLOT U (C1–C3, CO₂, H₂S) and 6 m CP-Sil 5 CB (C3–C9).
• Natural Gas Analyzer B Extended – includes CP-Molsieve 5A channel for permanent gases (He, Ne, H₂, O₂, N₂) with helium or argon carrier gas option.

Methodology

Samples are introduced via pressurized injection, internal pump with Tedlar bag, or continuous flow. All injector and sample lines are heated (≈110 °C) to prevent moisture condensation. Strategic backflush cycles remove CO₂, water, and heavy hydrocarbons to protect stationary phases and maintain retention time stability. A Micro-Gasifier accessory vaporizes LPG/LNG samples without cold spots for reproducible analysis.

Main Results and Discussion

Analyzer A achieves separation of C1–C3 (<90 s) and C4–C9 (<400 s).
Analyzer A Extended resolves C1–C12 within ≈240 s using three optimized columns and timed backflush.
Analyzer B quantifies H₂S alongside air, CO₂, CH₄ in ≈60 s, with C3–C9 separated on a secondary column.
Analyzer B Extended adds a molecular sieve channel for O₂/N₂/He/Ne/H₂ profiling; switching to argon carrier enables H₂ and Ne detection.
Retention time stability is enhanced by in-line filters (RTS option) and regular backflush, extending column life and reproducibility.

Benefits and Practical Applications

• Factory-tuned, plug-and-play systems reduce installation time.
• Portable design supports lab, on-line, at-line, and field measurements.
• EZReporter software automates calculations of calorific value, density, compressibility, and Wobbe index compliant with ASTM D3588, ISO 6976, GPA 2172.
• Flexible sample modes and stream selection enable multi‐stream or automated calibration workflows.

Future Trends and Potential Applications

Integration with SCADA/LIMS for real‐time online monitoring and data management.
Development of advanced column chemistries for heavier hydrocarbons and additional trace contaminants.
Enhanced automation and remote diagnostics via IoT and cloud connectivity.
Application of machine-learning algorithms for predictive maintenance and anomaly detection in gas composition data.

Conclusion

The Agilent 490 Micro GC Natural Gas Analyzer series provides a comprehensive, fast, and reliable solution for natural gas composition and calorific value analysis. Four configurable systems cover C1–C12 hydrocarbons, H₂S detection, and permanent gas profiling with minimal maintenance and compliance to industry standards.

References

1. Agilent 490 Micro GC Natural Gas Analyzers Data Sheet; April 2012.