V_2O_5-TiO_2 type catalysts are widely used for the catalytic decomposition of DXNs in the exhaust gas from waste incinerators. When a bag filter is used as a dust collector, exhaust gas (～160°C) from the bag filter is usually re-heated to more than 200C before the catalyst for higher catalyst activity and durability (Fig.1). It is, however, desirable to operate the catalyst at lower temperatures or without re-heating to save energy. Catalyst activity decreases mainly by the accumulation of sulfur compounds due to sulfur oxides in the exhaust gas during low-temperature operation (～ 2001). The catalyst deactivation by the sulfur oxides occurs in two ways, sulfation of such active catalyst components as vanadium and ammonium bisulfate formation plugging catalyst pores. The deactivation by the ammonium bisulfate is apparent especially when ammonia is injected into the gas for simultaneous DXN and NOx removal. In this paper we describe the development of a low-temperature DXN decomposition catalyst at Nippon Shokubai Co., Ltd.
展开▼
