Enhanced separation for paraffin wax using CO2-responsive emulsions based on switchable hydrophilicity solvents

Abstract

Wax precipitation leads to destructive harms in the exploitation and transportation of petroleum. Solvent treatments can remove paraffin wax easily but the separation of solvent relying on distillation is admitted inefficient. Aiming at enhancing the separation and recovery performance of paraffin wax, CO2-responsive emulsion (SHS/W emulsion) based on switchable hydrophilicity solvents (SHS) is adopted. Since the paraffin wax is dissolved, emulsified, and dispersed by SHS/W emulsion, SHS/W emulsion exhibits better removal performance than SHS. The paraffin wax is recovered effectively upon introducing CO2, which attributes to the transformation of SHS from hydrophobic to hydrophilic state. Compared with the SHS system, the recovery of paraffin wax is improved obviously by introducing surfactant Span80. Owing to the deprotonation of SHS by bubbling N2 and heating, 77.6% SHS is recycled after recovering paraffin wax. Here, the recycled SHS can be used to realize the removal of paraffin wax again. Thus, it is a promising and alternative strategy for realizing the sustainable and rapid removal of paraffin wax in the petroleum industry.