High temperature filtration in the process industry

Abstract

High temperature filtration from industrial processes offers various advantages in terms of increasing process efficiency, heat recovery and protection of plant installations. Extremely interesting and demanding applications are found in the process industry. This paper describes experimental investigations with a ceramic and two types of metal high temperature filter elements (sintered fleece and woven bags). All three element types have been tested on a laboratory pilot filter with different filtration velocities up to 2.5 m/min and temperatures ranging between ambient and 600°C. Operational differences between ceramic and metal filter media are derived from measurements of the pressure drop behaviour as well as the residual pressure drop of the filter elements. In case of metal filter elements, an additional parameter has to be considered, i.e. the change of media structure in dependence of temperature. For long-term stable operation of high temperature candle filters, a well designed pulse jet regeneration system is essential. Gravimetrically and optically conducted clean gas measurements show for the fleece structures extremely low clean gas concentrations in the range of a few μg/m 3. Higher values in the range of 10 mg/m 3 were obtained with woven metal bags. Woven metal bags are reasonable cheaper sintered metal fleece elements.