The influence of experimental factors in solvent extraction for hydrocarbon recovery from oil sludge was investigated using an orthogonal experimental design. The results indicated that temperature, solvent type, solvent blend, solvent to sludge ratio, and treatment duration had significant effects on hydrocarbon recovery. In this investigation, a response surface methodology used to optimize the conditions required to recover hydrocarbons from oily sludge. In addition, the effectiveness of solvent extraction using solvent blends of methyl ethyl ketone (MEK) and xylene for recovery and upgrading of oily sludge has been determined. Oily sludge used here consisted of 63% of its weight petroleum hydrocarbons. Based on the experimental data, a full quadratic model was generated. Optimization of influential parameters was conducted through the fitted model. As determined by the fitted model, the factors such as temperature, mixing time, MEK, and xylene to sludge ratios for optimum oil sludge recovery with solvent extraction method must be fixed at 49.28 °C, 22 min, 6.04 to 1, and 6.4 to 1, respectively. Under the optimum conditions, 64.04% extraction yield achieved using solvent blends of MEK and xylene according to the model. Using the combination of MEK and xylene for recovery of oil sludge, a maximum extraction yield of 61.44% as petroleum hydrocarbons obtained during experiments. Based on the results, combination of MEK and xylene as solvent blend demonstrated significant effect on hydrocarbon recovery in 6 to 1 and higher ratios.
Keywords: MEK; Oil sludge; Petroleum hydrocarbon; Solvent extraction; Xylene.