MULTI-STAGE COUNTER-CURRENT FROTH SETTLER AND METHOD OF USE

摘要

A method for recovery of bitumen from a bitumen-containing froth utilizes solvent and a single, froth settling vessel having a plurality of internals therein. The froth is first diluted with enough solvent to reduce the viscosity of the froth and the diluted froth is added to the vessel above the internals. Additional of the solvent is added to the vessel, either below the internals, intermediate the internals or both and is flowed counter-current to the diluted froth which is flowing downwardly over the plurality of internals. A gradient of solvent concentration relative to hydrocarbon concentration is formed through the internals which act as multiple stages of separation. The product, being bitumen and other light components, are carried with the solvent to the top of the vessel. The heavier components such as water, solids and asphaltene aggregates fall to the bottom of the vessel by gravity. Where paraffinic solvents are used, the solvent to bitumen ratio for the initial dilution of the froth is kept below a ratio at which the asphaltenes are rejected. Substantially all of the asphaltene rejection occurs in the settling vessel as the solvent to bitumen ratio increases therein.