TDLAS & QF Analyzers

TDLAS & QF Analyzers

TDLAS and QF analyzers are optical gas analyzers used for high-selectivity, online measurement of key species in process gas streams. TDLAS (tunable diode laser absorption spectroscopy) measures analytes such as H₂O, H₂S, and CO₂ by laser absorption, while quenched fluorescence (QF) analyzers measure oxygen from trace to percent levels. These techniques have significantly advanced online gas analysis for both quality control and process control, with an emphasis on lower operating cost and higher uptime.

TDLAS implementations are commonly in-situ (across a duct or probe-mounted) or extractive depending on pressure, temperature, and particulate/moisture conditions. The technique’s narrow spectral targeting supports strong selectivity and fast response, making it well suited to dynamic processes and safety-critical measurements. QF oxygen measurement provides sensitivity across a wide range and is often chosen where oxygen must be tightly controlled for safety, quality, or equipment protection.

Benefits include reduced cross-sensitivity, minimal consumables, and stable long-term operation compared to some traditional wet-chemistry or paramagnetic approaches in difficult services. H₂S measurement supports personnel and asset protection by enabling faster detection of hazardous conditions, while H₂O and CO₂ measurements support dehydration performance, gas quality specification, and carbon-management processes. Reduced maintenance burden and higher availability directly translate into lower lifecycle cost.

Applications include natural gas processing and transmission, refining and petrochemical units, sulfur recovery interfaces, carbon capture-related streams, combustion and flue-gas conditioning, and inerting or blanketing systems where oxygen control is essential. They are also deployed where rapid composition changes occur and where analyzer response time materially affects control stability or product quality.

Design and selection considerations include installation style (in-situ vs extractive), optical path length, pressure/temperature compensation needs, and the calibration/verification philosophy required by internal quality systems. Materials compatibility, purge concepts for optical windows, and hazardous-area requirements should be evaluated early. Interface and diagnostics capabilities are key to sustaining performance under real process conditions and minimizing unplanned interventions.

Engineered Equipment Company, a leading supplier of specialized industrial equipment.