Demulsification of phosphoric acid/ tri-n‑butyl phosphate (W/O) emulsion by a novel rotor-stator spinning disc device

Abstract

The demulsification process of phosphoric acid/tri-n‑butyl phosphate (W/O) emulsion is investigated by a novel rotor-stator spinning disc device (RSSDD). Emulsion properties varied with emulsification rotor speed and phase ratio, and operating parameters such as flow rate and disc speed have been studied for their effects on demulsification efficiency D, relative volume of separated oil phase λ, dispersed phase fraction of creamed emulsion ɸc and change in the average droplet size of emulsion Δdc. The results show that D is primarily due to emulsion stability. Low emulsification rotor speed and phase ratio reduce the emulsion stability, resulting in an increase in D. The shear and centrifugal forces from rotation and the residence time, influenced by operating parameters, play a major role in D and Δdc. Operating at higher disc speed and lower flow rate is not supposed. D decreases with increasing flow rate and decreasing disc speed, while Δdc behaves in the opposite way. λ disperses within 1.52%-2.94%, resulting in a linear relationship between D and ɸc. The optimal operating parameters are determined with D of 41.12% for one cycle in RSSDD. A model is proposed for the prediction of D and ɸc, showing an acceptable agreement with the experimental results.