Catalysts for Low-Temperature Decomposition of VOCs

摘要

Eltron Research, Inc., is currently developing multicomponent metal- oxide and supported noble-metal catalysts for the destruction of volatile organic compounds (VOCs) in air at low temperatures. The goal for this work is to produce a simple, cost-effective technology for reducing the concentration of VOCs in air to acceptable levels before the air is released into the atmosphere or recirculated. Specific application areas include ventilated work spaces for spray painting and engine maintenance (degreasing and fuel line repair), indoor air decontamination, dry cleaning, food processing (grills and deep fat fryers), fume hoods, residential use, and solvent-intensive industrial processes. The components of the catalysts were chosen based on their anticipated oxygen surface mobility, resistance to poisoning, multiple oxidations states, and documented activity for oxidation reactions. Catalysts were screened with and without dispersed platinum for conversion of 1-butanol, toluene, and methyl ethyl ketone (MEK) into carbon dioxide and water. The concentrations of VOCs in the feedstream were maintained at (caret)100 ppm, and the space velocity was between (caret)1,000 and 26,000/hr. Catalysts with the best overall performance in the absence of noble metals generated complete conversion of 1-butanol into CO2 at 150 deg. C, 47% conversion at 100 deg. C, and 15% conversion at 80 deg. C. For toluene these catalysts generated complete conversion at 200 deg. C, and conversions as high as 75% at 150 deg. C. Adding Platinum to these materials further improved low-temperature activity and routinely allowed greater than 50% conversion of VOCs to CO2 at temperatures of 100 deg. C and lower. Although it was generally found that catalyst destruction decreased in the order 1 -butanol MEK toluene, some of the most-active materials demonstrated different trends, as well as large disparities in activity for these VOCs.