Understanding Bitumen Recovery from Oil Sands through Colloidal and Interfacial Phenomena

Canadian oil sands are unconsolidated sand deposits that are impregnated with heavy, viscous petroleum, normally referred to as bitumen. The total bitumen in place in Alberta is estimated at 1.7 to 2.5 trillion barrels and is clearly massive by world standards. Presently, 25% of the Canadian energy needs are derived from upgraded bitumen from mined oil sands. The oil sands are a complex mixture containing bitumen, mineral solids, clays, connate water and salts. The bitumen recovery from the oil sands using water extraction processes involves bitumen separation from the sand grains and airbitumen attachment for subsequent flotation. Colloidal, interfacial and electrokinetic phenomena play a major role in bitumen recovery from oil sands using water based extraction processes. Through the use of basic scientific tools at the micro and molecular scales, we were able to understand the working of what is considered to be a mega scale industrial process. Electrophoretic and atomic force balance measurements were used to establish the reasons for the observed low bitumen recovery in the presence of fine solids and divalent ions. As well, impinging jet deposition experiments were utilized to ascertain the ability of air-bitumen attachment under different physicochemical environment. The behavior of the bitumen-water interface was studied to better understand the formation of stable water-in-bitumen emulsions. Langmuir trough and micro-pipette techniques were employed to elucidate the fundamental role of deemulsifiers. The presentation will illustrate how one can within a University environment study a complex industrial process that is of great importance to the Canadian Energy Sector. Proceedings of the International Conference on MEMS, NANO and Smart Systems (ICMENS’03) 0-7695-1947-4/03 $17.00 © 2003 IEEE