Venting purifier volatile

In purifying mixtures of gas-forming substances, activated carbon is utilized in cigarette filters (mainly in Japan), in gas-mask filters, in venting filters for car petrol tanks (mainly in the USA and Japan) and in air conditioning units for the purification of ambient air. Industry also utilizes activated carbon for the recovery of a multiplicity of volatile solvents from the ambient air, for adsorption of poisonous or noxious gases (e.g. hydrogen sulfide) and as catalysts or catalyst supports. 

The emission streams from purified terephthalic acid (PTA) plants commonly contain carbon monoxide, methyl bromide, and various volatile organic compounds (VOC s). Before the vent gas (offgas) is exhausted to the atmosphere, these contaminants (often regulated) must be destroyed, normally by the catalytic oxidation process. Currently, most commercially available catalysts are used at an inlet terrperature higher dian 350 C. The improvement of the catalyst activity is desired to increase the catalyst life-time and to reduce the operational cost. Additionally, the catalyst selectivity needs to be improved to minimize or eliminate the formation of polybromobenzenes (PBB s) which can cause plugging or blockage in process lines. 

The objective of this chapter is to illustrate the point of view of industry with some applications in volatile organic compound (VOC) abatement (i) vent gases from purified terephthalic acid (PTA) plants, (ii) nitrogen-containing VOC (acrylonitrile), (iii) regenerative oxidation catalyst technology. 

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