Synthesis of Additives Based on Polyethylenimine Modified with Non-ionic Surfactants for Application in Phase Separation of Water-in-Oil Emulsions

Abstract

Water-in-oil emulsions are formed during petroleum production. These emulsions are stabilized by natural emulsifiers present in the oil, such as asphaltenes, resins and paraffins, making their separation difficult. Various treatments can promote the breakdown of these emulsions, among them demulsification, which involves the addition of demulsifiers to promote separation of the water and oil phases. This work proposes the synthesis of demulsifiers by modification of branched polyethylenimine (PEI) with the introduction of different nonionic surfactants along the chain. Specifically, we used ethoxylated surfactants based on lauryl acid and nonylphenol, with different numbers of ethylene oxide units in their chains. The modified polymers were characterized by hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and solubility tests. Demulsifier systems were prepared by dissolving the additives in two solvent mixtures: xylene:ethanol and xylene:butylglycol. These systems were applied in demulsification ...