Odour control in wastewater treatment plants and sewage collection systems often requires the use of scrubber systems. Many of these scrubbers employ a wet process using a hypochlorite solution to remove hydrogen sulphide (H2S) from air streams prior to discharge. Monitoring the hydrogen sulphide in both inlet and discharge air has presented problems for standard sulphide gas sensors. ATI’s Q45S Wet H2S Gas Detector is a new type of gas sensor technology that allows continuous monitoring in this type of application, where condensing humidity conditions are normal.
The Q45S model is an odour monitoring system that uses our standard Q45 electronics package in conjunction with a special Wet H2S sensor. Measurements may be either at the inlet to scrubber systems where gas concentrations can run as high as 200ppm or at the outlet, where gas concentrations are ideally down below 0.5ppm. Special gas sensor configurations are available for either duct insertion or flowcell use.
Because Q45S Wet H2S Gas Detector systems are often monitoring gas streams with condensing levels of water vapor, provision has been made for eliminating water droplets from the gas sensor that could present a barrier to the diffusion of hydrogen sulphide into the sensor. An optional air-purge system controlled by the gas transmitter will periodically deliver a blast of air across the critical sensor surfaces to remove water droplets. This system insures a clear gas diffusion path to the sensor and reliable measurements on a continuous basis.
Q45S hydrogen sulphide transmitters provide a large, easy to read LCD display of H2S concentration with a second display line to indicate other status information. An alarm contact is available for external alarming functions, and a second contact may be used for alarm purposes if the air purge system is not implemented in a given application. An isolated 4-20 mA output is provided for remote data transmission, and output spans are user programmable for ranges of 0-2.000ppm up to 0-200.0ppm.
Hydrogen sulphide detector for wet gas applications