화학공학소재연구정보센터
Filtration & Separation, Vol.32, No.8, 789-793, 1995
EXPERIMENTAL INVESTIGATIONS INTO THE COMPRESSION OF DUST CAKES DEPOSITED ON FILTER MEDIA
Periodically regenerable cake-forming surface filters, and in particular bag filters incorporating reinforced nonwoven filter media, are widely used in particulate control technology. The particles collected on the filter medium's surface build up a so-called 'dust cake'. The operational characteristics of such filter apparatus are strongly influenced by the structure of the dust cake thus formed. The structure itself depends - among other factors - on particle size distribution, particle charge, adhesive and cohesive properties, and pressure drop. The dust cake mass and therefore its flow resistance and pressure drop increase with filtration time. This rise in pressure drop is in many cases not linear, but is characterised by sudden sharp increases. These jumps in the pressure drop result in a higher cleaning frequency, which is in most cases disadvantageous for filtration performance. Local compressions of the dust cake are believed to be responsible for the progressive increase of pressure loss with time. This theory was confirmed by quantitative analyses of dust cake structures. Locally determined porosities, particle and pore size distributions, and fractal dimensions of different - i.e. more or less compacted - dust cakes are presented and discussed in the paper.