PROCESS FOR EXTRACTING BITUMEN AND DRYING THE TAILINGS
A process for separating bitumen from bitumen ore material includes extracting bitumen with a hydrocarbon solvent to produce a bitumen-enriched solvent phase and tailings. The tailings are dried or stripped in a dryer to remove any remaining hydrocarbon solvent. The amount of solvent discharged in the tailings may be less than 4 bbl per 1000 bbl of recovered bitumen.
1 . A method comprising:
forming a first mixture by mixing bitumen ore material with a first hydrocarbon solvent;
separating the first mixture and producing first tailings;
forming a second mixture by mixing the first tailings with a second hydrocarbon solvent:
separating the second mixture and producing second tailings; and
separating the second hydrocarbon solvent from the second tailings with a heated gas that includes the second hydrocarbon solvent.
2 . The method of claim 1 wherein the heated gas includes steam.
3 . The method of claim 1 wherein the second hydrocarbon solvent is separated from the second tailings in a dryer that includes a plurality of separate drying trays.
4 . The method of claim 1 wherein separating the second hydrocarbon solvent from the second tailings includes moving the heated gas and the second tailings in a countercurrent fashion.
5 . The method of claim 1 wherein the second hydrocarbon solvent is separated from the second tailings in a fluidized bed.
6 . The method of claim 1 wherein the bitumen ore material includes tar sands.
7 . The method of claim 1 wherein the first hydrocarbon solvent includes a light aromatic solvent.
8 . The method of claim 1 wherein the second hydrocarbon solvent includes butane, pentane, and/or hexane.
9 . The method of claim 1 wherein the second hydrocarbon solvent includes pentane.
10 . A method comprising:
forming a mixture by mixing bitumen ore material with a hydrocarbon solvent;
separating the mixture and producing a solvent phase and tailings; and
separating the hydrocarbon solvent from the tailings by moving the tailings through a dryer that includes a plurality of drying trays.
11 . The method of claim 10 wherein the dryer includes sweep arms positioned adjacent to each of the plurality of drying trays to move the tailings across the plurality of drying trays.
12 . The method of claim 10 wherein separating the hydrocarbon solvent from the tailings includes moving heated gas through the tailings in the dryer.
13 . The method of claim 12 wherein the heated gas includes steam.
14 . The method of claim 12 wherein the heated gas input into the dryer includes the hydrocarbon solvent.
15 . The method of claim 12 wherein the heated gas and the second tailings move through the dryer in a countercurrent fashion.
16 . The method of claim 12 wherein at least one tray from the plurality of trays only heats the tailings indirectly from heat supplied by the heated gas and at least one other tray from the plurality of trays heats the tailings through direct contact with the heated gas.
17 . The method of claim 10 wherein the mixture is a second mixture, the bitumen ore material is first tailings, the hydrocarbon solvent is a second hydrocarbon solvent, the solvent phase is a second solvent phase, and the tailings are second tailings, wherein the method comprises:
forming a first mixture by mixing bitumen ore material with a first hydrocarbon solvent; and
separating the first mixture and producing a first solvent phase and the first tailings.
18 . The method of claim 10 wherein the bitumen ore material includes tar sands.
19 . The method of claim 10 wherein the hydrocarbon solvent includes butane, pentane, and/or hexane.
20 . A method comprising:
forming a first mixture by mixing bitumen ore material with a first hydrocarbon solvent;
separating the first mixture and producing a first solvent phase and first tailings;
forming a second mixture by mixing the first tailings with a second hydrocarbon solvent;
separating the second mixture and producing a second solvent phase and second tailings; and
separating the second hydrocarbon solvent from the second tailings in a fluidized bed.
21 . The method of claim 20 wherein a heated gas is used to fluidize the fluidized bed and the heated gas includes steam.
22 . The method of claim 20 wherein the bitumen ore material includes tar sands.
23 . The method of claim 20 wherein the first hydrocarbon solvent includes a light aromatic solvent.
24 . The method of claim 20 wherein the second hydrocarbon solvent includes butane, pentane, and/or hexane.