Evaluation of different demulsifiers for Marpol oil waste recovery

Abstract

Marpol oil waste composed of wasted oil with seawater which is challenging for waste treatment. Therefore, emulsified seawater has to be broken down for recovering the oil content involving chemical destabilizer to disperse water droplets or destroy emulsifiers.This study aims to evaluate 37 products of demulsifiers (cationic, non-ionic and anionic) based on ability of water removal from Marpol oil waste. The results show that anionic and nonionic surfactants were found to be effective demulsifiers exhibiting good property for oil and water separation. The efficiency of the nonionic demulsifiers increases with the dosage up to a certain extent after which the efficiency falls. However, anionic demulsifiers do not show any decrease in efficiency at higher doses. Among all the tested anionic demulsifiers, sodium dioctyl sulfosuccinate (ALCOPOL O70PG), sodium dioctyl sulfosuccinate (ALCOPOL O CONC 60%) and Oligoguluronate (DP9-6661) were with most outstanding performance. Additionally there is a general improvement in the performance of screened demulsifiers with increased temperature (70°C). Sodium dioctyl sulfosuccinate (ALCOPOL O70PG), sodium dioctyl sulfosuccinate (ALCOPOL O CONC 60%) and sodium dodecyl benzene sulphonate (DP9-6661) reached water removal performance percentage as 75%, 66.3% and 56.7% respectively after 30h. When the water content of recovered oil was reduced to a certain level (below 10%), the heat valve was about 40MJ/kg. The recovered Marpol oil waste was suggested to apply for low-quality fuel usage such as cement kilns and waste incinerators with its property of high energy value, low sulphur content and Polychlorinated Biphenyls (PCBs).