System and method of separating bitumen from tar sands
View Patent ↗Various methods and systems for obtaining bitumen from tar sands are disclosed. The disclosed methods and/or systems can be used to economically achieve a high degree of bitumen recovery from tar sands. The method may include a primary leaching or extraction process that separates most of the bitumen from the tar sands and results in a bitumen-enriched component and a bitumen-depleted component. The bitumen-enriched component includes mainly solvent and bitumen. The bitumen-depleted component includes mainly water and mineral solids with some residual bitumen and solvent. The bitumen-depleted component may be mixed with liquefied petroleum gas, e.g., propane and/or butane, to further separate the residual solvent and bitumen. The disclosed system can include separators configured to separate the various components at the various stages in the process.
1. A method for obtaining bitumen comprising:
mixing tar sands with a first hydrocarbon solvent, forming a first mixture;
separating the first mixture into a bitumen-enriched component and a bitumen-depleted component;
mixing the bitumen-depleted component with liquid LPG, forming a second mixture; and
separating the second mixture into a second bitumen-enriched component and a tailings component.
2. The method of claim 1 wherein separating the first mixture into the bitumen-enriched component and the bitumen-depleted component includes filtering the first mixture.
3. The method of claim 2 wherein the first mixture is filtered under a vacuum or under pressure.
4. The method of claim 1 comprising screening the tailings component to separate additional bitumen from the tailings component, and adding the additional bitumen to the first mixture.
5. The method of claim 1 comprising blowing a gas through the first mixture to separate the bitumen-depleted component from the first mixture.
6. The method of claim 1 wherein the bitumen-depleted component is mixed with the liquid LPG at a pressure that is greater than approximately 1.1 atmospheres.
7. The method of claim 1 wherein the first hydrocarbon solvent is a light aromatic solvent.
8. The method of claim 7 wherein the light aromatic solvent comprises toluene, xylene, biodiesel, light distillate, and/or naphtha.
9. The method of claim 1 wherein the first hydrocarbon solvent has a boiling temperature of approximately 50° C. to 375° C.
10. The method of claim 1 wherein the liquid LPG includes propane and/or butane.
11. The method of claim 1 wherein the liquid LPG has a boiling temperature of approximately −80° C. to 10° C.
12. The method of claim 1 wherein the tar sands include approximately 3 wt % to 20 wt % of bitumen.
13. The method of claim 1 wherein at least approximately 90 wt % of the bitumen from the tar sands is extracted.