Biodegradable Polymer for Demulsification of Water-in-Bitumen Emulsions

Removal of residual water from a solvent-diluted bitumen is a challenging task because the water drops, in the emulsified form of a few micrometers, are extremely stable. A nontoxic and biodegradable polymer, ethylcellulose, was used to break up emulsified water from naphtha-diluted bitumen. It was found that the ethylcellulose polymer at 130 ppm dosage removed up to 90% of the emulsified water in the diluted bitumen by gravity settling after 1 h at 80 degrees C. The tests, extended to bitumen froth containing about 10% solids by weight, showed a 90% removal of the water in the diluted bitumen froth. The addition of ethylcellulose also assisted the removal of fine solids with the water. However, for bitumen froths containing 30% or more solids, the efficiency of water removal by ethylcellulose addition was found to be less effective. Micrographic images revealed that ethylcellulose broke up the water-in-bitumen emulsions by flocculation and coalescence.