MTBE - A CARRIER FOR HEAVY OIL TRANSPORTATION AND VISCOSITY MIXING RULE APPLICABILITY

The pipeline transportation of bitumens is made difficult by the exces sive viscosities of the heavy oil. The current solution to this proble m has been the addition of C4+ paraffinic liquid hydrocarbons. There a re a number of drawbacks, however, to the use of this diluent. To over come these difficulties the alternate use of MTBE (methyl tert-butyl e ther), a gasoline additive, as a liquid solvent has been investigated. With the potential for Alberta to become a substantial exporter of bo th bitumen and MTBE, the prospect of transporting the two constituents simultaneously is promising. A liquid viscosity model has been utiliz ed to calculate the component viscosities as a function of temperature , and then use a mixing rule to determine blend viscosity as a functio n of composition. It was found that the addition of 25-30% MTBE (mass basis) was sufficient to reduce the viscosity of the Cold Lake bitumen to meet pipeline specifications. The viscosity model was found to be accurate over the entire range of compositions and temperatures examin ed. A simple distillation was performed on a 35% MTBE (mass basis) ble nd to study the ease of separation of the liquid diluent from the heav y oil phase at atmospheric conditions.