Demulsification of Water in Crude Oil via Biodegradable Cellulosic Polymer

Water in crude oil emulsions in the upstream oil industry causes serious problems such as corrosion and precipitation. Therefore, it is of crucial importance to demulsify and separate water at the production site. Demulsifiers’ performance is evaluated by its demulsification efficiency, cost, and biocompatibility. Restrictive environmental regulations have resulted in an ongoing effort to identify and characterize new demulsifiers which offer biodegradability while maintaining demulsification efficiency. In this study, biocompatible and biodegradable cellulosic polymers with trade names Walocel, Cellulose Acetate, Methocel-K3, and Methocel-E5 were used as demulsifiers. Demulsifiers’ performance was evaluated by bottle test using crude oil from the Sarvestan oil field. The initial tests revealed that Walocel and Methocel-E5 have better performance as compared with Cellulose acetate and Methocel-K3. It was found that increasing temperature up to 80 ⁰C and increasing demulsifier concentration up to 3000 ppm results in faster and more efficient demulsification. 90% separation of water at 80 ⁰C and a demulsifier concentration of 3000 ppm was achieved within 2 hours by Methocel-E5 while the same separation took 4 hours for Walocel. After 12 hours of demulsification at 80 ⁰C and a demulsifier concentration of 3000 ppm, Walocel and MEthocel-E5 could demulsify and separate 99% and 98% of the initial water respectively