Keco Model 100 and 200 H2S Gas Analyzers

Models 100 and 200 use a ratiometric-colorimetric detector that measures the rate of color change of lead acetate tape. As gas passes over the tape, an LED and photodiode optical system reads the color change; the microprocessor processes the signal and produces a linear 4-20 mA output. The method is specific to H2S and refers to ASTM D4084, D4468 and D4045.

Used in gas processing, natural gas pipelines, refineries, sales gas, biogas, landfills, LPG and LNG plants.

• Automatic zero and automatic calibration; can run with as few as four tape changes per year.
• Model 200 is offered with ATEX and IECEx options for Division 1/2 and Zone 1/2 hazardous areas.
• The sample is regulated to 10 PSI, flow is set with a flow meter and the sample is humidified before reaching the tape.
• Can be installed outdoors; internal heaters prevent freezing.
• Options include alarm relays, Modbus, SmartTalk software and wireless modem.

The choice between Model 100 and 200 depends largely on the installation site: Model 200 is preferred on sites requiring a hazardous area rating, and Model 100 in standard areas. Remote monitoring and web-based control can reduce the need for site visits.

Tetra selects the model suited to the hazardous area class, prepares the sample line and liquid separator, and sets alarm points together with operations during commissioning. Regular supply of tape and filter consumables is part of field service.