Fouling and subsequent disruption of filter coalescers due to deposition of coke particles is a crucial concern for petrochemical and oil-refinery plants. Our previous study confirmed that the γ-alumina ceramic microfiltration membranes could successfully remove coke particles from petrochemical oily wastewater. The aim of the current study is preliminary design and economic evaluation for implementation of ceramic membrane unit (CMU), as a pretreatment for coalescer filtration unit, to elucidate the applicability of the process in petrochemical wastewater treatment. Using CMU not only increases the lifetime of the filter coalescers but also introduces a supplementary source for the production of dilution-steam-water (DSW). Two types of ceramic membranes, including 7- and 19-channel modules, were analyzed with the latter providing better performance for the full-scale application. Total number of the required membrane modules was calculated considering the fact that one flow pass through the tubular membrane is adequate for the reasonable elimination of coke particles from the feed. Accordingly, a continuous cross-flow filtration procedure provided with a system of concentrate recycle was suggested. Total capital investment elements were calculated for the CMU implementation. Economic studies showed that the break-even point (BEP) and payback period (PBP) are near 3% and 2 yr, respectively. The results indicated that the CMU is a potential pretreatment for coke removal from petrochemical effluents.
