Oxygen analyzer and sensor solutions for air separation units, PSA/VPSA nitrogen and oxygen generators, cryogenic air separation plants, industrial gas cylinder filling, and gas purity verification applications.
Air separation and industrial gas production are among the most measurement-intensive processes in modern industry. Whether you are operating a large cryogenic air separation unit (ASU), a pressure swing adsorption (PSA) nitrogen generator, a vacuum pressure swing adsorption (VPSA) oxygen plant, or a cylinder filling station, specialty gases, accurate oxygen measurement is essential at every stage of production, purification, and distribution.
Oxygen analyzers serve two distinct and equally critical roles in these applications. In nitrogen and inert gas production, oxygen measurement verifies that the product meets purity specifications and is free from residual oxygen contamination. In oxygen production and enrichment applications, analyzers confirm that product concentration meets the required grade — whether for industrial, medical, or specialty gas use.
This application note covers the major oxygen monitoring requirements across cryogenic air separation, PSA/VPSA gas generation, cylinder filling, and industrial gas distribution operations, and identifies which Southland Sensing analyzers and sensors are best suited for each stage of the process.
Southland Sensing analyzers monitor oxygen concentrations from parts-per-billion impurity levels to 100% oxygen purity, providing a complete measurement solution for virtually every stage of industrial gas production.
Why Gas Analysis Matters in Air Separation Units:
Air separation plants produce high-purity oxygen, nitrogen, argon, and specialty gases used in industries where even trace contaminants can impact product quality, process efficiency, and equipment reliability.
Continuous oxygen monitoring helps operators: Verify product purity, Protect cryogenic equipment, Monitor purification systems, Optimize ASU performance, Meet customer specifications.
Carbon dioxide must be removed before cryogenic separation to prevent freezing within heat exchangers and distillation columns. Continuous CO₂ monitoring helps verify purification system performance and protects critical cryogenic equipment.
The OMD-675 is Southland Sensing’s ultra-trace oxygen analyzer for air separation units, PSA nitrogen generators, cryogenic product streams, and specialty gas production. With measurement capability down to parts-per-billion oxygen concentrations (0–1 ppm full scale), it is ideal for verifying gas purity, monitoring purification systems, and protecting critical production processes. Standard analog and Modbus RTU communications provide seamless integration with SCADA and DCS control systems for continuous 24/7 operation.
Designed for high-purity oxygen verification, the OMD-740 provides accurate measurement of oxygen-enriched gas streams using suppressed measurement ranges optimized for oxygen production. Ideal for VPSA oxygen plants, cryogenic ASUs, medical oxygen manufacturing, and cylinder filling operations, it helps verify product purity and maintain stringent customer and regulatory specifications.
✓ Suppressed Measurement Ranges for Purity
The OMD-640 combines laboratory-grade parts-per-billion oxygen measurement with the convenience of a portable analyzer. Ideal for spot-checking high-purity nitrogen and specialty gas systems, commissioning new gas generation equipment, troubleshooting oxygen contamination, and verifying gas purity across multiple sampling points, it delivers reliable ultra-trace oxygen analysis wherever it’s needed.
✓ Portable Parts-Per-Billion Oxygen Analysis
Designed specifically for OEM integration, the OMD-507 combines reliable online oxygen measurement with a compact footprint ideal for PSA nitrogen generators, VPSA oxygen plants, and skid-mounted gas generation systems. Its space-efficient design allows manufacturers to deliver continuous oxygen monitoring without sacrificing performance or valuable panel space.
✓ Configurable · OEM-Ready Design
Accurate oxygen analysis in air separation and industrial gas applications depends not only on the analyzer selected, but also on a properly designed sample conditioning system. Gas streams in these applications may contain moisture, trace hydrocarbons, particulates from molecular sieve beds, and pressure differentials that must be managed before the sample reaches the analyzer cell.
For trace oxygen measurement in nitrogen and inert gas streams, sample system cleanliness is especially critical — even small leaks in the sample tubing or fittings can introduce ambient air contamination and produce falsely elevated readings. All sample system connections should be leak-tested and wetted materials selected for compatibility with the process gas and expected trace contaminants.
For high-concentration oxygen streams (VPSA/ASU oxygen production), sample systems must be constructed from materials compatible with oxygen service to prevent combustion hazards. Cleanliness of all wetted components is mandatory in oxygen-rich service.
Southland Sensing provides application engineering support to help customers specify appropriate sample handling systems for both trace and percent-range oxygen measurement in air separation and gas generation applications. Contact the factory to discuss your process pressure, flow conditions, moisture content, and installation requirements.
Oxygen-deficient and oxygen-enriched atmospheres both present serious and potentially fatal hazards in industrial gas production facilities. Liquid nitrogen, liquid argon, and other cryogenic inert gases can rapidly displace oxygen in enclosed spaces, creating life-threatening hypoxic conditions with no visible warning. Conversely, liquid oxygen storage and distribution areas present a fire and explosion risk from oxygen enrichment.
Fixed ambient monitors should be installed at appropriate elevations throughout all enclosed production buildings, cylinder storage areas, liquid gas storage rooms, and filling stations. Our OMD-351 series monitors provide continuous room-air O₂ measurement with audible and visual alarms at user-configurable setpoints (typically 20.0% for high oxygen warning and 19.5% for low oxygen alarm), supporting compliance with OSHA and local facility safety 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.
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