Advances in the Use of Ceramic Candle Filters for Hot Gas Clean-up. Removing Dust Particles with Sticking Properties
Publications of 1999 - Abstract
Advances in the Use of Ceramic Candle Filters for Hot Gas Clean-up. Removing Dust Particles with Sticking Properties.
K. Hübner, R. Schulz, W. Eberhard, K. Görner
Lehrstuhl für Umweltverfahrenstechnik und Anlagentechnik, Universität Duisburg-Essen
Various ceramic media for the cleaning of gases at high temperatures up to more than 1000°C are already commercially available and semi-technical scale investigations as well as some pilot scale facilities have shown that in principle the separation of particles at high temperatures from gas streams may take place without major problems which, however, occur often in connection with the cleaning cycle of the dust loaded filter medium. Especially, low melting eutectic components in the dust particles may cause strong adhesion forces between the sampled particles in the filter cake and the filter medium resulting in a dust load that cannot be easily removed from the filter, at least not by means of pulse jet cleaning. The pressure drop will strongly increase and in many cases the filter cake is even irreversibly fixed to the filter elements. The separation of comparably low melting dust particles has been studied at ambient and at higher temperatures including those at which sticking and melting of the particles occurred. The filter media were made of aluminium silicate fibres. To overcome problems with the removal of the dust load from the filter elements solid additives were used increasing the melting point of the particles and thus declining the adhesion forces between particles and the surface area of the filter elements. The additives applied offer besides the enhancement of the high temperature particulate separation process the advantage of removing simultaneously gaseous components like hydrogen chlorides from the stack gases of municipal incinerator flue gases. Another method to decrease adherence forces between filter and dust may be a coating of the filter medium.