Detecting filter-cake pathologies in solid-liquid filtration: semi-tech scale demonstrations using electrical resistance tomography (ERT)

Solid-liquid filtration monitoring by means of a single inexpensive 16-elem ent ring sensor array for electrical resistance tomography (ERT) is describ ed. The high sensitivity of the UMIST Mark 1b-E data acquisition system led to the unexpected finding that this tomography array can detect movement o f the liquid level during filtration. This degree of sensitivity was also c apable of detecting any tilt of the filter assembly, so that pathological b ehaviour due to malfunction or accidental displacement of the filter suppor t plate could also be identified. Moreover, illustrative distortions of a f ilter cake formed by artificial surface depressions were readily observed i n tomograms reconstructed by linear back projection. It is concluded that E RT has great potential for instrumenting and detecting 'pathological' behav iour of filtration processes in the pharmaceutical and fine chemicals indus tries. (C)2000 Elsevier Science S.A. All rights reserved.