Demulsification and Ultrafiltration of Water-Oil Emulsions

To increase the specific productivity and efficiency of membrane processes for the separation of stable emulsions of the “oil-in-water” type, the efficiency of commercial demulsifiers (surfactant-based) and inorganic reagents has been investigated. Changes in particle size of the dispersed phase of an emulsion and changes in the value of the ζ-potential of emulsions, depending on the concentration of the added demulsifier, have been determined. When using commercial demulsifiers for the aggregation of particles of the dispersed phase of the emulsion, the most effective reagent is SNPKh 4315; at 50 mg/dm3 concentration of this reagent in the emulsion, a 1.8-fold increase in the particle size of the dispersed phase of the emulsion is observed (without external changes in the emulsion). The addition of sulfuric acid with a concentration of 3260 mg/dm3 to the emulsion leads to a 35-fold increase in the particle size of the dispersed phase of the emulsion, and the emulsion decomposes into an aqueous and oil phase within 4 hours. Thus, sulfuric acid was used to demulsify the emulsion. The decomposition of the emulsion made it possible to increase the productivity of the ultrafiltration membranes (more than 2 times), and the retention capacity of the membranes for oil products increased to 99.9 %.