Optical in-situ measurement of filter cake height during bag filter plant operation

A pilot scale jet pulsed bag filter test facility is operated at conditions similar to those of the industrial bag filters. The facility is equipped with a stereo vision based optical system for in-situ cake height distribution measurements on the bag filter surface. Experimental data are presented and data evaluation procedures are discussed to elaborate the features of the measuring system.The results show that the cake height distribution becomes narrower towards the end of filtration cycles. A steep pressure drop rise is observed at the start of a filtration cycle in the absence of re-attachment and a non-uniform bag cleaning, which may be attributed to different cake properties. The specific cake resistance remains constant over the linear part of the pressure drop curve indicating a non-compressible cake formation.The analysis of residual cake patches shows a large number of small sized cake patches and a few large sized cake patches on the filter surface. The cake patch size increases with the cake formation. The fractal analysis of patches boundary indicates preferential cake formation at the boundary of the residual cake patches shortly after regeneration.