Oxygen, hydrogen sulfide, and carbon dioxide analyzer and sensor solutions for upstream extraction, midstream processing, downstream refining, and chemical & petrochemical manufacturing operations.
The oil, gas, chemical, and petrochemical industries operate some of the most demanding and hazardous process environments in the world. Accurate measurement of oxygen (O₂), hydrogen sulfide (H₂S), and carbon dioxide (CO₂) is essential throughout the value chain—from upstream production and gas gathering systems to midstream pipeline operations, refining, petrochemical processing, and specialty chemical manufacturing.
Whether monitoring oxygen ingress in natural gas pipelines, measuring H₂S in sour gas streams, verifying inert atmosphere integrity in storage tanks, protecting catalysts from contamination, or optimizing combustion efficiency at fired heaters and flare systems, reliable gas analysis plays a critical role in personnel safety, process reliability, regulatory compliance, and asset protection.
This application note reviews the major gas monitoring requirements across upstream, midstream, downstream, chemical, and petrochemical operations and highlights the Southland Sensing analyzers, sensors, and gas monitoring solutions best suited for each application.
Why gas monitoring matters: Continuous or intermittent measurement of O₂, H₂S, and CO₂ helps protect workers from toxic and explosive atmospheres, verifies process gas purity, prevents equipment corrosion from oxygen or acid gas contamination, and supports regulatory reporting requirements across API, OSHA, and EPA standards.
OMD-625
Full-featured rack-mount O₂ transmitter with 4–20 mA output and Modbus RTU for SCADA / DCS integration. Ideal for continuous online oxygen monitoring in gas processing plants, pipeline control rooms, and refinery operations requiring sub-ppm sensitivity.
H2S-740
Engineered for explosive and hazardous process environments. ATEX & IECEx certified for Ex db ib IIB T4 Gb zones — required for installations in classified areas around natural gas compression stations, hydrocarbon processing units, and chemical plants.
⚠ ATEX · IECEx · IIB T4 Gb
OMD-640
Compact portable analyzer for spot-checking oxygen levels during pipeline commissioning, tank purging verification, and maintenance inspection rounds. Ideal where permanent installation is not practical or where mobile analysis is required across multiple sampling points.
CO2-625
Space-saving in-line transmitter suited for skid-mounted process units, chemical injection skids, and compact gas processing systems where panel space is limited but continuous online measurement is still required.
✓ Configurable Design
Accurate gas analysis in oil, gas, and petrochemical applications depends not only on the analyzer itself, but also on a correctly designed sample conditioning and handling system. Process streams in these industries frequently contain liquid hydrocarbons, particulates, water vapor, and other contaminants that must be properly managed before the sample reaches the analyzer.
Key sample system design factors include proper pressure letdown, moisture and liquid separation, filtration, flow control, and material compatibility with the process gas composition. In sour gas and corrosive service applications, wetted materials must be carefully selected to avoid accelerated sensor or component degradation.
For hazardous area installations, sample system design must also conform to area classification requirements and applicable electrical codes (NEC, IEC, ATEX).
Southland Sensing provides application engineering support to help customers specify appropriate sample handling systems for demanding oil, gas, and petrochemical service. Contact the factory to discuss your process conditions, gas composition, pressure, temperature, and site classification requirements.
Refer to our O₂ Sensor Compatibility Guide to confirm the correct sensor for your analyzer model and process application.
Our application engineers assist with sensor selection, installation, and hazardous area questions.
Our application engineers are available to assist with sensor selection, installation guidance, and hazardous area classification questions for your hydrogen production system.
English English 
German
Chinese
Spanish
Japanese
Russian
Portuguese
French
Vietnamese
Korean
Turkish
Italian
Arabic
Ukrainian
