Recombination of hydrogen bonds clipping interfacial film effectively for dehydrated tight oil

Abstract

Tight oil is an important unconventional oil resource. However, during the extraction process of tight oil, a large amount of tight oil emulsion is generated, combined with offshore oil releases, have caused serious environmental problems. Owing to the high content of resin molecules, which adsorbed the interfacial water molecules in the form of hydrogen bonds, as well as tightly bound resin molecules via π–π stacking, the interface structure is stable; hence, it is difficult to separate oil and water. In this study, the hydrogen-bond energy of O atoms in common groups and water molecules was analyzed, and the efficient separation of oil and water was realized by the regulation of hydrogen-bond energies of the demulsifier molecules and interfacial water molecules. The O atoms in EO, PO, ester group and hydroxyl group were named as Type 1–6 O atoms. The compatibility of the demulsifier and tight oil was improved by the introduction of an aromatic structure, which combined with the tight oil molecules via π–π stacking. At the same time, by the introduction of Types 1–6 O atoms, the electronegativity (Hydrogen bond acceptor ability) of the demulsifier molecules was optimized to improve the hydrogen-bond energy formed between the demulsifier and water molecules effectively; then, the interfacial resin molecules were replaced to form stronger hydrogen bonds with water molecules, weakening the π-π stacking interaction between resin molecules for clipping the interfacial film; thus, the mass-transfer efficiency of water molecules at the oil–water interfacial is enhanced.