NGA Analysis with ISO6974-3 Nexis Nexis GC-2030ISO6974-3 GC-2014ISO6974-3

Significance of the Topic

Accurate determination of natural gas composition is essential for calculation of physical properties such as heating value and specific gravity, ensuring compliance in procurement, custody transfer, and process control.

Aims and Overview of the Study

This application note describes a method based on gas chromatography (ISO6974-3) for simultaneous analysis of permanent gases and hydrocarbons C1–C8 in natural gas samples.

Methodology and Instrumentation

• Two‐valve two‐channel system equipped with three packed columns.
• MS‐13X column with thermal conductivity detector (TCD‐2) separating He, H2, O2, N2, CH4, CO; Porapak‐N pre‐column for back‐flushing C2+.
• Porapak‐T column in series with TCD‐1 and flame ionization detector (FID) for C2–C8 hydrocarbons and CO2.
• LabSolution workstation software with BTU and specific gravity calculation modules.

Key Results and Discussion

Typical chromatograms demonstrate baseline resolution of light gases and hydrocarbon isomers within analysis time under 10 minutes. Detection ranges cover trace levels (0.0001%) to major component concentrations, ensuring repeatability and sensitivity.

Benefits and Practical Applications of the Method

• Comprehensive analysis of both permanent gases and a broad hydrocarbon range.
• Rapid throughput suitable for QA/QC and process gas monitoring.
• Integrated software streamlines calculation of heating value and relative density.
• High sensitivity and reproducibility across a wide concentration span.

Future Trends and Potential Applications

Emerging developments include coupling with mass spectrometric detection for enhanced speciation, miniaturized GC systems for field deployment, and expanded automation for real-time monitoring in pipeline networks.

Conclusion

The described GC configuration offers a robust and versatile solution for natural gas composition analysis in compliance with ISO6974-3, delivering reliable data for physical property calculations and quality assurance.

Instrumentation Used

• GC-2030/GC-2014 with dual TCD channels and FID.
• MS-13X, Porapak-N, Porapak-T packed columns.
• LabSolution workstation software.