Gas cleaning at high temperatures using rigid ceramic filters

Rigid ceramic filters have emerged in the last two decades as the most promising technology for particulate removal from process gases at temperatures up to 1000°C. Granular and fibrous forms of media have been developed and both are commonly employed in the form of cylindrical ‘candles’ which are periodically cleaned by application of a reverse gas pulse. Research has focused on this cleaning process, which governs the long-term performance of the filter. The problem is 2-fold: to determine the dust cake ‘detachment stress’, which depends on the dust particle properties and cake structure, and to understand the propagation of the cleaning pulse which is applied to remove it. The results of research in these areas are summarized and experimental methods for the investigation of filter cleaning briefly described. The implications for design and further development of ceramic filters are discussed.