Combustible measurement

15 June 2005

Emerson Process Management’s new Rosemount Analytical OCX 8800 can analyse flue gases at temperatures up to 1427 degrees C.

Accurate measurements of flue gases are essential to optimise combustion fuel-to-air ratios and to ensure safety during the combustion process, in hot water and steam boilers, refinery process heaters and reactor furnaces.

Incorporating the zirconium oxide sensor used for oxygen measurement in the Rosemount Analytical Oxymitter 4400, the OCX8800 also introduces a patented catalytic bead combustibles sensor. Typically installed near the process, an eductor draws a flue gas sample through the filter to the sensors, and then returns it to the process.

Optional in-situ filters and sample tube blow-back are available for processes carrying particulates. Dilution air is added to the sample to ensure accurate combustibles measurement even in the absence of oxygen in the flue gas stream: this enables the OCX8800 to continue both measurements through process upsets, such as burner fouling, process tube leaks or loss of flame.

The OCX8800 unit features integral or remote mounted electronics, in weatherproof and ATEX approved housings, with a vacuum fluorescent local display for improved visibility. The unit is completely field-repairable with easy access to the internal sensor components and the plug-in electronics module.

Two separate 4-20mA output signals offer field-scaleable outputs of oxygen and combustibles levels, with HART digital communications providing diagnostic data, available to an engineering department asset management PC system running AMS Suite: Intelligent Device Manager software.