title: Optimized liquid-liquid extractive rerefining of spent lubricants.
abstract: Central composite design methodology has been employed to model the sludge yield data obtained during liquid-liquid extractive rerefining of spent lubricants using an alcohol (1-butanol) and a ketone (methyl ethyl ketone) as prospective solvents. The study has resulted in two reasonably accurate multivariate process models that relate the sludge yield (R (2) = 0.9065 and 0.9072 for alcohol and ketone, resp.) to process variables (settling time t, operating temperature T, and oil to solvent ratio r). Construction of such models has allowed the maximization of the sludge yield (more than 8% and 3% in case of alcohol and ketone, resp.) so that the extraction of useable oil components from spent lubricants can economically be performed under extremely mild conditions (t = 16.7 h, T = 10°C, and r = 2) and fairly moderate conditions (t = 26.6 h, T = 10°C, and r = 5) established for the alcohol and ketone correspondingly. Based on these performance parameters alcohol appears to be superior over ketone for this extraction process. Additionally extractive treatment results in oil stocks with lesser quantity of environmentally hazardous polyaromatic hydrocarbons that are largely left in the separated sludge.
authors.affiliation: Department of Applied Chemistry and Chemical Technology, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Muhammad Ashraf
authors.initials: MA
authors.lastname: Kamal
authors.affiliation: Department of Applied Chemistry and Chemical Technology, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Syed Mumtaz Danish
authors.identifier: 0000-0003-0354-3994
authors.initials: SM
authors.lastname: Naqvi
authors.affiliation: Department of Chemical Engineering, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Fasihullah
authors.initials: F
authors.lastname: Khan
mesh_terms: D020001:1-Butanol; D002074:Butanones / Q000737:chemistry; D059625:Liquid-Liquid Extraction / Q000379:methods*; D054327:Lubricants / Q000737:chemistry*; D008956:Models, Chemical; D015999:Multivariate Analysis; D012044:Regression Analysis; D012722:Sewage; D012997:Solvents; D013696:Temperature
chemical_list: D002074:Butanones; D054327:Lubricants; D012722:Sewage; D012997:Solvents; C005222:methylethyl ketone; D020001:1-Butanol