Liquefied dimethyl ether based multi-stage extraction for high efficient oil recovery from spent bleaching clay. (December 2021)

• Record Type: Journal Article
• Authors: Zhang, Dong; Huang, Ying; Oshita, Kazuyuki; Takaoka, Masaki; Wang, Quan; Sheng, Changdong; Lin, Zizeng
• Is Part Of: Waste management. Volume 136(2021)
• Page Start: 204
• Page End: 212
• Publication Date: 2021-12
• Subjects: Oil recovery -- Spent bleaching clay -- Liquefied dimethyl ether -- Adsorption equilibrium -- Multi-stage batch extraction; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2021.09.033
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: DME can quick and effectively recover oil from spent bleaching clay (SBC). Over 80 wt% oil can be recovered through 5-stage DME extraction. Equilibrium model of oil extraction from SBC by DME was approached. Light petroleum hydrocarbon and SFA were preferentially extracted from SBC. Abstract: With the increasing production of spent bleaching clay (SBC), the recovery of the waste oil in SBC is becoming an important and urgent needs for our environment and economy. In this research, we have developed a new effective recovery technique to recover oil from SBC by use of liquefied dimethyl ether (DME). Over 65 wt% oil and 81% wt.% oil are efficiently recovered from SBC under equilibrium single-stage extraction conditions and multi-stage extraction conditions, respectively based on the systematically investigation to the effects of the DME/SBC ratio, extraction time, stirring speed and extraction stage number on oil recovery via a batch extractor. Compared with using other extraction solvents, the extraction solvent DME can be reused without heating and therefore significantly reduce the energy consumption during the oil recovery process. In addition, the quantitative oil extraction relationship is derived from the adsorption equilibrium model and is well verified by experimental results. The results show a great potential for using this oil recovery technique in SBC as well as in the large amount of oily sludge and oil sands.