The measurement principle is based on a variation of HENRY's law: the weight of any gas dissolved in a definite volume of liquid is directly proportional to the partial pressure the gas exerts above the liquid at a constant temperature.

The Analyser consists of a stripping system coupled with an H2S Analyser NOVASULFTM HG SERIES.


The liquid sample enters an insulated, heated sample handling cabinet and then passes through a pressure regulator to maintain a constant pressure for the liquid sample sweep. The sample feeds through a final filter which protects the metering pump. A metering pump continuously injects measured quantities of sample and is mixed with flowing nitrogen, at a constant and measured flow-rate,. The blend then enters a vaporiser with an adjustable nozzle which sprays the blend into a glass chamber. This phenomenon causes the stripping of H2S into the nitrogen. The degassed liquid falls into a reservoir and then to the drain. At the same time, the nitrogen containing H2S in proportion to that in the original liquid, is piped directly to the NOVASULFTM HG SERIES H2S Analyser.

The benefits of this technology can be summarised as follows:

  • Measurement specific to H₂S
    No interference from other components
  • Wide range capability
    Measures between 0-2ppm H₂S to 0-100%  H₂S
  • Low volume humidifier
    Response times as low as 30 seconds
  • Single Optical Sensor
    Eliminates temperature drift
  • Fibre optic link between housings
    Reduces affects caused by ambient
    temperature swings
  • Up to 2 detection modules per controller
    Minimises capital investment

With its wide-ranging ability to measure Total Sulphur and/or H₂S from % levels down to ppb levels, the TG400 range of Total Sulphur process analysers can be utilised in many process industries, including:

Ethylene / Propylene Plants
Reformer recycle gas
Offshore gas production
Fuel gas monitoring
Catalyst protection
Sour gas treatment plants