Treatment of Cutting Oil Emulsion by Electro-Oxidation Process

Abstract

Wastewaters comprising oil-in-water (O/W) emulsions are generated in many industrial processes such as food processing, petroleum refining, petrochemical and metal finishing industries. A large amount of waste oil water emulsion is thus generated in this fashion worldwide every year by various industries. In the present study, demulsification of soluble oil-emulsion was done by electro-oxidation (EO) using a Ti/RuO2 in batch and continuous mode. The effect of pH, current, flow-rate and electrolysis time on the removal efficiencies of demulsification process was examined. Box behnken design (BBD) under response surface methodology (RSM) was used to optimize the selected process parameters. The BBD model fits very well with the experimental data. The R2 value for percentages removal efficiencies of oil, turbidity, COD and energy consumption were 0.9833, 0.9894, 0.9976, and 0.9913 in batch mode respectively, 0.9535, 0.9858, 0.9819, 0.9849 and 0.9781 for oil, turbidity, COD, energy consumption and mass transfer coefficient in continuous mode respectively. The optimum pH, current and electrolysis time were found to be 7.23, 0.50 A, and 99 min and elapsed time, flow-rate and current was 170 min, 2.2 cc/min and 1.11 A for batch and continuous modes, respectively. The experimental values oil, turbidity and COD removal at optimized conditions are found to be 98.83 %, 99.90% and 94.93% for batch process and 92.90%, 98.99% and 91.36% for continuous process, respectively. Mass transfer coefficient for continuous process found to be 0.658 (m/hr). Minimum energy consumption for batch and continuous process are 2.833 (KWh/m3) and 19.57 (KWh/m3).