Supra-Molecular Asphaltene Relaxation Technology

Abstract

The asphaltene components of heavy oil can become serious problems during fractionation, particularly the toluene-soluble and pentane-insoluble fractions. Asphaltenes are composed of mixtures of thousands of different molecules with complicated chemical structures that form three-dimensionally entangled macromolecular structures. In general, a “supra-molecule” refers to a molecular assembly in which each molecule cooperatively interacts with the others through different types of noncovalent bonds. The resulting supramolecule can express several complicated and specific properties. Asphaltene may form such a supramolecular structure, because asphaltene molecules interact cooperatively with each other through interactions related to poly-aromatic rings such as aromaticaromatic and charge-transfer ones. Every asphaltene supra-molecule exhibits distinct, characteristic properties and different reactivities. The chemical reactions of each individual molecule determine the reactivity of the entire assembly. Therefore, an understanding of these molecular and supra-molecular structures is essential for developing strategies to control their reactivity. Although structural analyses have been performed on asphaltenes, the true molecular weight of asphaltenes has not yet been determined. Vapor pressure osmometry (VPO) and size exclusion chromatography (SEC) 61 Journal of the Japan Petroleum Institute, 56, (2), 61-68 (2013)