A semifluidized bed was proposed to alla ' 1, bed plugging during the filtration of fines-hydrocarbon suspensions. Mitigation of plugging was allowed by alternating semifluidization during capture with unconstrainedfluidi7ation for removal of' deposits. Solids holdup conditions were established to prevent deposition in thefluidi7ation section. The cyclic parameters were varied to allow efficient removal of deposits during filti washino. Analysis with a -ation model accounting.for solids detachment in thefixed bed section revealed that the fluidization section favored growth of aggregate size entering the fixed bed. Analysis oj' the split ratios between fixed and fluidized bed heights revealed that the shallovvestfluidi7ation sections delayed deposition in thefixed bed. In cyclic operation, reversibilit y of the senuflUidi7ed bed was best recovered via gas i. n]. ecti. on during the washing stages. However, the filtratiOn times in successive cycles shortened with increasing washing times but lengthened with increasing the washing supeificial suspension velocity. (c) 2008 American Institute of Chemical Engineers.