Permanent Gas Analyser CO - CO2 Analyser

Significance of the Topic

The analysis of permanent gases, light hydrocarbons, and sulfur components is essential in the oil and gas industry and in environmental monitoring. Reliable gas analysis methods support process control, safety, and regulatory compliance.

Objectives and Overview

This document presents a customized Permanent Gas Analyser (PGA) based on gas chromatography, optimized for rapid, accurate quantification of H2, O2, N2, CH4, CO, CO2, light hydrocarbons, and sulfur compounds. It supports industry-standard methods such as ASTM D1946, D2504, D2505 and UOP 603.

Methodology and Instrumentation

The PGA uses a Thermo Trace 1300/1310 GC platform with InstantConnect injector and detector modules. A single-channel TCD system provides baseline detection of permanent gases with options to add:

• FID detector or methaniser-FID for sub-ppm hydrocarbon and CO/CO2 analysis
• Second TCD channel with Ar or N2 carrier for optimized H2 detection
• Extended hydrocarbon channel up to C20 with capillary columns and FID
• Additional channel with FPD or PFPD for low-level sulfur detection
• Multi-stream selector or stop-flow valve for unattended and precise sampling

The column configuration typically includes a Molsieve column for H2–CO separation and a Hayesep column for CO2, hydrocarbons, and H2S, mounted in a valve oven (40–250°C). Sulfinert® tubing ensures inert sample paths for corrosive gases.

Main Results and Discussion

The PGA achieves analysis times under 10 minutes, detection limits down to 50 ppm (TCD), a dynamic range spanning four orders of magnitude, and accuracy better than 1 % RSD. Optional methaniser-FID extends sensitivity for low-ppm CO/CO2, and FID channels allow hydrocarbon speciation up to C20. Robust diaphragm valves and modular detectors ensure high uptime and reduced maintenance.

Benefits and Practical Applications

Key advantages include rapid turnaround, compliance with recognized standards, flexibility to tailor channel configurations for specific gas matrices, and minimal downtime. The PGA is suited for applications in natural gas quality control, LPG analysis, petrochemical feedstock monitoring, and environmental emissions testing.

Future Trends and Possibilities

Advancements may include integration of compact GC systems for sub-60-second analyses, expanded detector arrays for trace-level impurity profiling, enhanced automation and remote diagnostics, and broader adoption of digital data management platforms for real-time monitoring.

Conclusion

The customized Permanent Gas Analyser offers a versatile, reliable solution for comprehensive gas and hydrocarbon analysis. Its modular design, compliance with ASTM and UOP methods, and robust performance deliver high analytical throughput and accurate results for industrial and environmental laboratories.

References

• ASTM D1946 Standard Test Method for Analysis of LPG by Gas Chromatography
• ASTM D2504 Standard Test Method for Analysis of Gaseous Hydrocarbons
• ASTM D2505 Standard Test Method for Analysis of Natural Gas by Gas Chromatography
• UOP Method 603 Carbon Monoxide/Carbon Dioxide Analyser
• Interscience Application Note 203WA1301A Permanent Gas Analyser