The major challenge towards industrial gas filtration process is collection of finest particles by filter media with least energy and also achieving longest possible life of filter media. This leads to quite significant technological intervention for designing appropriate filter media as well as filtration system. For enhancing filter media performance, understanding filter material behaviour under different operating parameters (e.g., level of filtration velocity, cleaning intensity and mode of cleaning, temperature and humidity) is very important. In the development of industrial filter media, a common approach is enhancing surface filtration. Filter media are mostly nonwoven with membrane/coating, or it could be woven structure in case of glass with membrane for high temperature filtration. Understanding filter media behaviour in real situation is very complex and cannot be accomplished using present system of characterization techniques. The filter media (differing in composition) possessing same initial physical, mechanical and filtration properties can behave differently during industrial filtration situation. Selection of suitable operating parameters should also be governed by filter media characteristics besides the application requirement. Study reflects that pulse pressure parameters in a pulse jet fabric filtration system should be set in accordance with fibre fineness in the media, maintaining a balance between emissions and operational pressure drop across the media. Further higher pulse pressure is better in the case of higher media dust loading.
Every attempt must to be made to minimize aerodynamic and mechanical damage, chemical degradation, temperature degradation, thermal shrinkage, particle clogging and blinding, condensation and sublimation during filtration. Since even small membrane damages will allow dust penetration through the fabric, one of the major challenges is the development of strong membrane without affecting permeability characteristics. Needless to say media performance at high heat is most critical and challenging. In case of hot gas filtration, quite significant decrease in breaking strength with time is quite common thus affecting life of the filter bag. The decrease in the breaking strength of the filter fabric is a result of fiber degradation at high temperature and flexing of filter media during pulse cleaning. The filter materials differing in composition possessing same initial strength can have different level of strength after exposing to hot gas filtration. Stiffer material structure besides the right choice of raw material is therefore important for high temperature filtration. The same will be highlighted following a case study...
Session: K2 - Keynote Lecture II
Day: 22 October 2019
Time: 14:45 - 16:00 h