Synthesis of a low-temperature demulsifier with dual-hydrophobic chains through a simple low-temperature process

Abstract

The extraction of crude oil generates a significant volume of stable emulsions that can lead to various adverse effects in industrial extraction processes. Therefore, emulsion demulsification is a crucial step. In this paper, PGDA, a low-temperature W/O demulsifier with double hydrophobic chains, was synthesized from poly(ethylene glycol) diacrylate by a simple low-temperature process. The structure of PGDA was analyzed by FTIR and 1H NMR, and the demulsification performance was evaluated by a bottle-testing method. The results demonstrated that PGDA, at a concentration of 500 mg/L, achieved a demulsification efficiency of 100 % under low-temperature conditions (45 °C) over a 5-hour period. Furthermore, it also showed good demulsifying performance in wide pH range (6–10) and high salinity (100,000 mg/L). In addition, the possible mechanism of demulsification of PGDA was investigated by zeta potential, interfacial tension, and three-phase contact angle, etc. PGDA showed strong competitive adsorption ability with asphaltenes at the interface. PGDA has the ability to navigate rapidly to the oil–water boundary and displace the native surfactants there, thus destabilizing the emulsion and thus promoting the separation of oil and water. PGDA by virtue of the simple synthesis process, low demulsification temperature and high efficiency are of practical application.