Reliable Sulphur Impurity Measurement at ppb Levels in Pure CO2 Matrices

Carbon Dioxide (CO₂ ) is currently used in industrial applications such as energy, food, water treatment or for process cleaning. CO₂ must be provided with high quality levels of purity to define its grade. Contamination with hydrocarbons, sulphur compounds or other molecules can occur create a need for an analytical solution to quantify low level of concentration for such compounds.

In the case of sulphur applications, some key players in the energy sector need to separate and quantify at ppb levels and continuously for certain compounds such  as H₂S, SO₂, COS, CS₂, CH₃SH, C₂H₅SH and C₄H₃SH. Capabilities to quantify with high speciation in a pure CO2 matrix at ppb level is a great challenge!

Chromatotec (France) has adjusted its automatic gas chromatographs to provide continuous monitoring capable of tracking such compounds at levels of concentration close to 5 ppb with a high sensitivity level lower than 1 ppb.

A specific configuration offers a turnkey solution based on specific sulphur detectors (SSD) with combined detector solutions (wet cell detector) using autoGC, gas generators, calibration device using mass flow controllers for linearity tests and automatic data validation and multiplexing system for up to 6 streams of analysis (at different stages of the process).

This complete solution fulfills the criteria in terms of separation quality and requested sensitivity. It even allows having redundancy of results for a better control of the process. All the results provided are validated using internal calibration thus avoiding gas cylinder use for calibration and carrier gas.