A study of organic/inorganic interactions in syncrude fines by x-ray photoelectron spectroscopy and core electron energy-loss spectroscopy

Abstract

Surface analysis including x-ray photoelectron spectroscopy (XPS), core electron energy-loss (CEEL), and temperature programmed oxidation–XPS have been used to characterize the fines from a tar sand oil obtained by extraction of a western tar sand, a shale oil obtained by retort of a western shale, and a coal liquid produced by direct liquefaction of a sub-bituminous coal. Our results identify the modes of interaction involved between different organic and mineral types. In tar sand fines, the major mineral component is clay. The dominant organic interaction with the clay phase is with N-rich asphaltenes. In shale, the major mineral component is Ca and Ca/Mg carbonates while clay represents a minor component. The major bonding between the organic and mineral phases is a cation–carboxylate interaction. However, the clay continues to bind up a substantial fraction of the N-rich organics although it represents a minor phase. In coal liquid, the fines consist of a heterogeneous mix of organic and mineral phases. The mineral particles, in particular Fe, are strongly associated with organics. CEEL analysis of the organics shows highly aromatic structure. Comparing organics on fines with coal feed indicates hydrogen incorporation during coal liquefaction.