Universal Natural Gas Analyzer for Natural Gas and Natural Gas Liquids by Capillary Gas Chromatography, Available as a Preconfigured Agilent Technologies Analyzer

Significance of the Topic

Natural gas composition analysis is critical for accurate energy content assessment, pipeline quality control, and environmental compliance. Capillary gas chromatography delivers improved resolution, speed, and sensitivity compared to traditional packed columns, enabling comprehensive multi-component analysis in a single run.

Objectives and Overview of the Study

This application note presents a preconfigured Agilent Technologies Universal Natural Gas Analyzer for simultaneous quantification of permanent gases and extended hydrocarbons in natural gas, natural gas liquids, and liquefied petroleum gas. The method employs dual chromatographic channels to provide detailed component separation alongside an optional composite C6+ screening mode.

Methodology and Instrumentation

The analytical configuration comprises two parallel channels:

• TCD channel: series liquid and gas sample valves, split inlet, microfluidics Capillary Flow Technology Deans Switch, HP-PLOT Q and Molsieve PLOT capillary columns, and a thermal conductivity detector.
• FID channel: series liquid and gas sample valves, split inlet, DB-1 capillary column, flame ionization detector, and a six-port backflush valve for optional hexanes plus composite analysis.

Instrumentation Used

• Agilent 7890B GC with G3440B options for sample valves, electronic pressure control modules, Deans Switch, and backflush valves.
• HP-PLOT Q, Molsieve PLOT, and DB-1 capillary columns.
• Thermal conductivity detector (TCD) and flame ionization detector (FID).

Main Results and Discussion

The dual-channel system achieved baseline separation of permanent gases (O2, N2, CO2, CH4, C2) and light hydrocarbons up to C6 on the TCD channel, while the FID channel resolved extended C3–C5 isomers. Incorporating backflush enabled an early hexanes plus composite response, reducing cycle time when detailed C6+ speciation is unnecessary. The method aligns with GPA standards 2186, 2286, 2261, and 2177, demonstrating enhanced performance over packed column approaches.

Benefits and Practical Applications of the Method

• Comprehensive analysis of permanent gases and hydrocarbons in a single run.
• Improved resolution, sensitivity, and speed with capillary chromatography.
• Flexible sample introduction (gas, liquid, or combined phases).
• Optional composite C6+ backflush for rapid screening.
• Compliance with multiple industry standards.

Future Trends and Applications

Integration with automated sampling systems, real-time data processing, and coupling to mass spectrometry is anticipated. Advances in microfluidic GC may enable portable field analyzers, while machine learning algorithms could streamline data interpretation for process monitoring and environmental reporting.

Conclusion

The Universal Natural Gas Analyzer, equipped with capillary flow technology, dual detectors, and backflush capability, offers a versatile and efficient solution for natural gas and NGL analysis. It delivers superior sensitivity, resolution, and throughput on a single platform, meeting industry standards and providing flexibility for diverse laboratory and field applications.

References

1. Coleman S. Analysis of Permanent Gases and Extended Hydrocarbons in Natural Gas and Natural Gas Liquids by Capillary Gas Chromatography. Agilent Technologies Application Note 5991-2886EN; 2013.
2. Gas Processors Association. GPA Standard 2186: Method for the Extended Analysis of Hydrocarbon Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Temperature Programmed Gas Chromatography; Tulsa, OK.
3. Gas Processors Association. GPA Standard 2286: Method for the Extended Analysis of Natural Gas and Similar Gaseous Mixtures by Temperature Program Gas Chromatography; Tulsa, OK.
4. Gas Processors Association. GPA Standard 2261: Analysis for Natural Gas and Similar Gaseous Mixtures by Gas Chromatography; Tulsa, OK.
5. Gas Processors Association. GPA Standard 2177: Analysis for Natural Gas Liquid Mixtures Containing Nitrogen and Carbon Dioxide by Gas Chromatography; Tulsa, OK.