Accurate, low-maintenance hydrogen sulphide and total mercury monitoring in industrial applications

It can be of great importance to monitor concentrations of hydrogen sulphide, H2S, both for process control purposes, for safety reasons, and to demonstrate compliance with emission limits. However, H2S concentrations have been difficult to measure. Until now, most system solutions have been based on SO2 scrubbers followed by H2S-to-SO2 converters and detection of the resulting SO2 concentration. Such systems are often maintenance intensive and prone to problems related to the scrubber and other system components.

OPSIS is now introducing a new measurement approach. The OPSIS “Hot Wet Extractive” system design is used in combination with a long-life, proprietary converter. The resulting components in the output from the converter are reliably detected with a low-maintenance OPSIS UV-DOAS gas analyser. There is no need for any maintenance-intensive scrubber and no risk for SO2 interferences.

A similar converter-based approach is also available from OPSIS to monitor concentrations of total mercury (Hg, THg). It gives the same reliable and low-maintenance benefits as the OPSIS H2S system.

Whether monitoring H2S or THg or both, the same, single UV-DOAS gas analyser can also be configured to measure concentrations of other process-related gases such as NO, NO2, SO2, and NH3. This gives a very cost-effective gas monitoring system.