Plasma catalysis of diesel exhaust using industrial wastes a study on NOX and THC removal

Abstract

Air pollution, caused by large scale consumption of fossil fuels such as diesel, has been the leading cause of several adverse environmental effects such as global warming, higher acidity in rainwater, lower yield of agriculture production and several health issues. Diesel has been the primary and inevitable fuel source of energy worldwide, in both stationary power supplies and automobile applications. Several developing countries like India continue to rely heavily on usage of diesel fueled machinery and automobiles, which has resulted in high soot, particulate and hazardous gas emissions. The prominent gaseous pollutants of concern are the oxides of nitrogen (NOX) and total hydrocarbon content (THC) present in the diesel exhaust. Though efficient systems have been discovered for reducing soot and particulate emissions, treatment techniques for removal of gaseous pollutants are yet to reach a similar level of progress. Therefore, research efforts aimed at identifying treatment techniques for curbing hazardous gaseous pollutants are a welcoming step towards addressing the pertinent issue of air pollution. The gaseous pollutants emitted from the diesel engine can be reduced by applying control strategies at the level of engine design (pre-combustion) or as an aftertreatment technique of the exhaust stream (post-combustion). Although the pre-combustion control strategies are limited by the possible engine design modifications, the postcombustion approach allows for greater flexibility and scope by utilizing a variety of plasma discharges, catalysts and adsorbents. One such post-combustion strategy which involves treatment of NOX/THC using non-thermal plasma (NTP) generated from dielectric barrier discharge (DBD), has yielded promising results at the laboratory level. Non-thermal plasma produces an oxidative environment containing several charged species, which include energetic electrons, excited species, ions, and radicals, at atmospheric pressure and ambient temperature conditions...