FIELD PERFORMANCE OF NEW TWO-POINT (PPB/PPM) HYDROGEN SULFIDE CONTINUOUS EMISSIONS MONITOR (CEM)

This paper presents field test results for a new two-point continuous hydrogen sulfide monitor (CEM) combining a versatile two-point sampling system with two independent H2S Gas Loggers: one for measuring 0 to 200 ppm; +/- 1 ppm, the other for measuring from 0 to 2 ppm; (+/- 5 ppb below 100 ppb, +/-5%% at or above 100 ppb). The CEM is designed for monitoring of scrubbers, carbon adsorbers, biofilters and biotrickling filters.The sample conditioning system pulls gas streams independently from each sampling point at a flow rate of 2 liters per minute in order to minimize time lag between sampling and measurement. The unused gas sample streams are returned to the scrubber inlet or alternatively can be passed through internal filtration within the sampling system and exhausted to the atmosphere. The CEM system is programmed such that a measurement for each sampling point is taken once every ten minutes. A 4-20 mA real time signal representing the most recent sample measurement is then output from each Gas Logger. The data is also stored internally in each Gas Logger for later downloading via an IR transmitter. The downloaded data can be analyzed using existing OdaLog software and/or exported to popular spreadsheet programs.The Gas Loggers themselves are based on the rugged, proven and reliable OdaLog technology. In addition to the stored and output electronic signals, each Gas Logger displays the most recent measurement result on an easy to read LCD display. The Gas Loggers and the sampling system are housed in a heated NEMA cabinet that maintains a constant 100 deg. F temperature. This helps to ensure Gas Logger stability and minimize moisture problems in the sample stream. An optional thermoelectric AC unit is available for installations in hot climates. The Gas Logger units are designed for minimal maintenance (twice a year) and easy field functionality testing using calibration gas. The sampling system requires only annual maintenance.