Extended Refinery Gas Analyzer Nexis GC-2030ERGA2 GC-2014ERGA2

Importance of the topic

The detailed analysis of natural gas and refinery gas mixtures is essential for determining key physical properties such as heating value and relative density. Accurate compositional data ensure safe handling, process optimization, and compliance with regulatory standards in the energy and petrochemical industries.

Objectives and study overview

This method describes the comprehensive determination of gaseous components ranging from permanent gases (O₂, N₂, CO, CO₂, H₂S) to hydrocarbons (C₁–C₁₃) in refinery gas streams. The goal is to provide reliable analytical data for property calculations and continuous process monitoring.

Methodology

The analysis employs a gas chromatograph configured with four switching valves and nine columns. Key steps include:

• Sample introduction via four fixed-volume loops.
• Pre‐column backflushing of C₆⁺ as a single peak to the second oven.
• Separation of C₃–C₅ hydrocarbons on an alumina capillary column with FID detection.
• Permanent gas separation (O₂, N₂, CH₄, CO) on a molecular sieve (MS‐5A) with FID, while CO₂, C₂ species and H₂S are resolved on an Rtx-Q PLOT column and detected by TCD.
• Transfer of backflushed C₆–C₁₃ to an Rtx-1 capillary column in a second oven, with FID detection.
• Total run time of approximately 30 minutes.

Used Instrumentation

• Shimadzu Nexis GC-2030ERGA2 or GC-2014ERGA2 gas chromatograph
• Four switching valves and nine columns (Alumina capillary, MS-5A, Rtx-Q PLOT, Porapak-N, Rtx-1)
• Detectors: one thermal conductivity detector (TCD) and two flame ionization detectors (FID)
• Split/splitless injector for potential liquid hydrocarbon analysis
• Dual oven configuration with LabSolution workstation software including BTU and specific gravity calculations

Main results and discussion

The method achieves baseline separation of all target analytes with detection limits dependent on concentration ranges. Typical calibration ranges include:

• Permanent gases: O₂ and N₂ from 0.01 % to 20–50 %, CH₄ 0.01–10 %, CO/CO₂ 0.01–5–20 %, H₂S 0.05–30 %.
• C₂ hydrocarbons (C₂H₂, C₂H₄, C₂H₆): 0.01–10 %.
• C₃–C₅ hydrocarbons: 0.001–5 % for propanes and propene; 0.001–1 % for butanes, butenes, pentanes.
• C₆–C₁₃ hydrocarbons: 0.001–1 %.

Representative chromatograms demonstrate sharp, well‐resolved peaks for each compound class across three detector channels, confirming robust performance for both light and heavy hydrocarbons.

Benefits and practical applications

The described GC configuration offers:

• Comprehensive quantitation of permanent gases and C₁–C₁₃ hydrocarbons in a single run.
• Rapid, reproducible results to support process control, quality assurance, and billing applications in refineries and gas processing plants.
• Capability to extend analysis to heavier fractions (up to C₁₈) via a second oven.

Future trends and potential uses

Advancements may include higher‐throughput valve systems, integration of advanced detectors (e.g., micro-electro-mechanical sensors), enhanced automation with AI‐based peak identification, and further miniaturization for field‐deployable analyzers. Expansion into real‐time monitoring and process analytics will drive next‐generation refinery gas analysis.

Conclusion

This extended refinery gas analyzer method provides a reliable, efficient solution for detailed compositional analysis, enabling accurate property calculations and improved operational control in gas processing and petrochemical industries.

Reference

ASTM D1945, ASTM D1946, ASTM D3588, GPA-2261