Method for extracting bitumen from an oil sand stream
View Patent ↗The present invention provides a method for extracting bitumen from an oil sand stream, the method including at least the steps of: (a) providing an oil sand stream; (b) contacting the oil sand stream with a liquid comprising a non-aqueous solvent thereby obtaining a solvent-diluted oil sand slurry; (c) screening the solvent-diluted oil sand slurry thereby obtaining a screened oil sand slurry and a rejects stream; (d) introducing the rejects stream into a liquid bath; (e) transporting the rejects stream through the liquid bath to a space above the surface of the liquid bath; and (f) extracting bitumen from the screened oil sand slurry obtained in step (c).
1. A method for extracting bitumen from an oil sand stream, the method comprising at least the steps of:
(a) providing an oil sand stream;
(b) contacting the oil sand stream with a liquid comprising a non-aqueous solvent thereby obtaining a solvent-diluted oil sand slurry;
(c) screening the solvent-diluted oil sand slurry thereby obtaining a screened oil sand slurry and a rejects stream;
(d) introducing the rejects stream into a water bath from a confined space;
(e) transporting the rejects stream through the water bath to a space above the surface of the water bath, wherein the space above the water bath is the atmosphere and the rejects stream is transported through the water bath under a weir, the weir separating the confined space from the atmosphere; and
(f) extracting bitumen from the screened oil sand slurry obtained in step (c).
2. The method according to claim 1 , wherein the non-aqueous solvent comprises an aliphatic hydrocarbon.
3. The method of claim 2 wherein the aliphatic hydrocarbon has from 3 to 9 carbon atoms per molecule.
4. The method of claim 3 wherein the aliphatic hydrocarbon has from 4 to 7 carbons per molecule.
5. The method according to claim 1 , wherein the rejects stream as obtained in step (c) has a particle size of above 5 mm.
6. The method according to claim 1 , wherein the rejects stream as obtained in step (c) has a particle size of above 10 mm.
7. The method according to claim 1 , wherein the water bath has a temperature of above the atmospheric boiling point of the non-aqueous solvent.
8. The method according to claim 1 , wherein the non-aqueous solvent is at least partially removed from the rejects stream, before entering the rejects stream into the liquid bath in step (d).
9. The method according to claim 1 , wherein in step (e) the rejects stream is transported in an upwards direction.
10. The method according to claim 1 , wherein the pressure in the confined space is from 0.001 to 0.35 barg.
11. The method according to claim 1 , wherein the temperature in the confined space is from −20° C. to 100° C.