Deasphalting and demetallising oil - by treatment with organic carbonate

摘要

Crude oil or its fractions are deasphalted and demetallised by (a) contacting the liq. feed with an organic carbonate (I) until a solid rich in asphaltenes and metals is pptd., and (b) sepg. the solid. (I) is of formula RO-CO-OR', where R and R' = 1-3C alkyl, or R+R' = CH2CH2 or CH2CHMe. (I) is dimethyl carbonate (Ia). The (I)/feed wt. ratio is 0.5-4 (esp. 2). Step (a) is effected at 20-150 deg.C, esp. 80 deg.C using (Ia), for 2-360 (esp. 2-60) mins. Step (b) is effected by settling, centrifuging, filtration or hydrocyclone sepn. at the same temp. as in step (a). The resulting liq. phase is cooled and/or treated with a solvent more polar than (I) to induce sepn. of an oil-rich raffinate and a (I)-rich extract.