PROPYLENE-OXIDE ETHYLENE-OXIDE BLOCK-COPOLYMERS AS DEMULSIFIERS FOR WATER-IN-OIL EMULSIONS .2. EFFECTS OF TEMPERATURE, SALINITY, PH-VALUE, AND SOLVENTS ON THE DEMULSIFICATION EFFICIENCY

The effects of temperature, NaCl concentration (salinity), pH value, a nd solvents on the demulsification efficiency of propylene oxide (PO)- ethylene oxide (EO) block copolymers in the breaking of synthetic wate r-in-benzene emulsions stabilized by petroleum asphaltenes have been t horoughly investigated. The demulsification efficiency of the studied polymeric surfactants was found to increase with increasing temperatur e and decreasing salinity of the aqueous phase. A neutral pH value of the aqueous phase of the emulsion was found to be optimal for efficien t demulsification. Water and water compatible solvents were found to b e the best solvents for the prepared demulsifiers with respect to demu lsification properties.