Measuring H2S in Natural

Hydrogen sulfide (H₂S) is a toxic and corrosive contaminant found in Natural Gas.Even at low parts per million (ppm) levels, H₂S corrodes pipelines, processing equipment and storage infrastructure, leading to severe operational challenges and noncompliance with regulations. Precise concentration monitoring is therefore essential to safeguard personnel, prevent equipment degradation, and uphold product quality standards. As regulatory frameworks tighten and the push for cleaner energy intensifies, monitoring H₂S levels has become critical to mitigating environmental risks, maintaining operational integrity, and strictly adhering to evolving safety protocols. However, the broad variability and compositional complexity of these gas matrices present a substantial challenge to reliably and selectively measuring H₂S.

Advantages of TDLAS with a Multipass Cell

Pipeline tariffs in North America typically cap H₂S at 4 ppm, and European grid specifications are similarly strict. Verifying compliance requires reliably measuring single-digit ppm of a gas whose composition changes from one delivery to the next. TunableDiode Laser Absorption Spectroscopy (TDLAS) is capable of measuring H₂S with the
required sensitivity.

There are two things that make that difficult. First, H₂S absorption is relatively weak. Second, hydrocarbons absorb in the same spectral region, which creates interference with the H₂S absorption lines.