Liquid-liquid extraction and adsorption on solid surfaces applied to used lubricant oils recovery

Abstract

-In this work, the recovery of base oils from waste lubricants following the steps of solvent extraction, adsorption on solids and solvent removal by evaporation was evaluated. In the step of solvent extraction, the most efficient was 1-butanol, followed by tert-butanol, 2-propanol and ethanol; for the step of adsorption, activated carbon was the most effective solid for PAH removal, confirming the similarity of these compounds with petroleum aromatic fractions. Thus, the optimum solvent-adsorbent pair for the recovery of used lubricant oils through the proposed methodology was 1-butanol/activated carbon. At the end of the process, it was possible to establish a set of steps that permit the recovery of lubricant base oils with lower content of contaminants.

Recent advances in waste lube oils processing technologies

“…Several selective solvents were used in solvent‐extraction process, such as methyl ethyl ketone (MEK) , butanol followed by MEA , butanol‐propane and butanone , 1‐butanol and toluene , alcohol‐ketone‐HC , 1‐butanol followed by tert‐butanol, 2‐propanol, and ethanol , ethanol, 1‐butanol, and mixture of 1‐butanol/ethanol , acetic acid glacial , N‐methyl‐2‐pyrrolidone , also the acid treatments (sulfuric acid, phosphoric acid, acetic acid and formic acid) followed by clay earth treatment . The most critical parameters for the selection of a solvent are the types, the ratio of solvent to oil, and temperature of extraction .…”

“…The degradation of TBN value indicates regular oil changes . Generally, the acidity in waste lube oils is removed by adsorbents, that is, activated clay, egg shale, almond shale, date palm kernel powder, acid activated date palm kernel powder, and walnut shale powders , alumina and silica gel , activated carbon, silica‐gel, rice husk, silica‐NH2, residues from acetylene synthesis, babaçu epicarp, and benzoin gum , chitosan powder, activated carbon and silica powder .…”

“…It only requires <10%‐volume of waste lube oils as raw materials compared to crude oil and only one‐third of energy consumption . A number of techniques have been used in waste lube oils purification and reprocessing, such as coagulation, oxidization of sulfuric acid, vacuum distillation , extraction , hydro‐treating , and adsorption . However, the common technologies for re‐refining waste lube oils still involve several processes which are relatively expensive because of the high energy consumption and the secondary pollution .…”

Model Prediction and Optimization of Waste Lube Oil Treated with Natural Clay

“…In addition to the high expense due to the amount of clay needed, the recovered oils obtained through this process still have relatively high metal percentages [15]. The use of activated carbon has also been reported in the literature and the results showed a highly effective waste engine oil treatment by polycyclic aromatic hydrocarbon (PAH) removal [16]. Process optimization and oil property improvement achieved through acid modification of clays is now generating a renewed interest by researchers in recycling waste engine oil [17,18].…”

Catalytic Deacidification of Vacuum Gas Oil by ZnO/Al2O3 and Its Modification with Fe2O3

“…Neutralization or caustic washing might cause emulsion problems and product loss. Solvent extraction requires a large amount of solvent, which is complex and needs lots of energy for solvent recovery [3][4][5][6]. So, it is important to adopt a simple, high efficiency, environmentally-friendly, and economical deacidification technology to remove NAs from the crude oil and fractions.…”