Trace metal composition of Green River retorted shale oil

Abstract

Crude shale oils from an aboveground and two in-situ retorting processes were characterized for 26 trace element constituents. The shale oils were pyrolysed from Green River Formation oil shale by pilot plant or semiworks-sized facilities. Trace elements were resolved into those predominantly associated with suspended shale fines or emulsified water, and those more intimately associated with the shale oil matrix. The abundance of the metals As, Co, Fe, Hg, Mo, Ni, Sb, Se, V and Zn were quantified in whole and fractionated shale oil samples; the possible chemical nature of several metals is discussed. Based on the shale oils examined, the following observations were noted: the shale oils contained moderately high levels of Fe (33–63 ppm) and As (9.3–29 ppm), and lower quantities of Co, Mo, Ni, Se and Zn (≈1–10 ppm); most trace metals were associated with asphaltene or resin components; relative to reported mean values for petroleum, the As, Co, Fe, Mo and Se were more prevalent in Green River shale oil; in-situ retorting processes appeared to introduce Mo into the product shale oil.