Solvent Assisted Water Extraction of Oil Sands

Abstract

Described is a process for extracting bitumen from oil sands. Water is mixed with oil sands to form a slurry. The slurry and a hydrocarbon solvent are passed through a hydrotransport pipeline to form an extracted slurry. Dilution water is added to the extracted slurry to form a diluted extracted slurry to reduce the viscosity of the slurry to assist in subsequent bitumen separation. A flocculant may be added to assist subsequent separation or to reduce dilution water requirements.

1 . A process for extracting bitumen from oil sands comprising:
 adding water to the oil sands to form a slurry;   passing the slurry and a hydrocarbon solvent through a hydrotransport pipeline to form an extracted slurry; and   adding dilution water to the extracted slurry to form a diluted extracted slurry to reduce slurry viscosity to assist in subsequent separation.   
     
     
         2 . The process of  claim 1 , further comprising adding a flocculant to assist subsequent separation or to reduce dilution water requirements. 
     
     
         3 . The process of  claim 2 , wherein 1 to 50 ppmw of the flocculant is used based on oil sands weight. 
     
     
         4 . The process of  claim 3 , wherein 5 to 15 ppmw of the flocculant is used based on oil sands weight. 
     
     
         5 . The process of  claim 2 , wherein the flocculant is a polymer flocculant. 
     
     
         6 . The process of  claim 5 , wherein the flocculant is an anionic polymer flocculant with molecular weight above 500,000. 
     
     
         7 . The process of  claim 5 , wherein the flocculant is an anionic polymer flocculant with a molecular weight of above 1,000,000. 
     
     
         8 . The process of  claim 1 , wherein the solvent is added to the slurry in the hydrotransport pipeline. 
     
     
         9 . The process of  claim 1 , wherein the solvent is mixed with the slurry before the slurry is introduced into the hydrotransport pipeline. 
     
     
         10 . The process of  claim 1 , wherein the dilution water is added to the extracted slurry in the hydrotransport pipeline. 
     
     
         11 . The process of  claim 1 , wherein the dilution water is added to the extracted slurry after the extracted slurry exits the hydrotransport pipeline. 
     
     
         12 . The process of  claim 1 , further comprising separating the diluted extracted slurry into a bitumen extract and tailings. 
     
     
         13 . The process of  claim 12 , wherein the separation is effected by gravity separation. 
     
     
         14 . The process of  claim 12 , further comprising passing the bitumen extract to a product cleaning system to remove fines and water and to produce a cleaned bitumen extract. 
     
     
         15 . The process of  claim 14 , wherein the product cleaning system is an electric treater. 
     
     
         16 . The process of  claim 14 , wherein a portion of the cleaned bitumen extract is recycled back into the hydrotransport pipeline. 
     
     
         17 . The process of  claim 12 , further comprising recovering a portion of the solvent from the cleaned bitumen extract to form a diluted bitumen product. 
     
     
         18 . The process of  claim 17 , further comprising recycling the portion of the solvent recovered from the cleaned bitumen extract back into the hydrotransport pipeline. 
     
     
         19 . The process of  claim 12 , further comprising recovering a portion of the solvent from the tailings. 
     
     
         20 . The process of  claim 19 , wherein the recovering of the portion of the solvent comprises the use of steam or a hot gas stripping tower to raise the temperature of the tailings to assist solvent recovery. 
     
     
         21 . The process of  claim 12 , further comprising passing the tailings through tailings hydrotransport. 
     
     
         22 . The process of  claim 21 , further comprising adding a flocculant into the tailings hydrotransport to assist fines settling. 
     
     
         23 . The process of  claim 22 , wherein 50 to 500 ppmw of the flocculant is added into the tailings hydrotransport. 
     
     
         24 . The process of  claim 17 , wherein an amount of the solvent is retained in the diluted bitumen product to meet pipeline transportation specifications. 
     
     
         25 . The process of  claim 12 , further comprising withdrawing a middling stream from the diluted extracted slurry. 
     
     
         26 . The process of  claim 25 , further comprising adding a flocculant to the middling stream to separate fines and recycle water to form a concentrated fines slurry. 
     
     
         27 . The process of  claim 1 , wherein the solvent comprises one or more of the following: an n-paraffin, an iso-paraffin, a cyclic-paraffin, an olefin, and an aromatic hydrocarbon, wherein the solvent has a bromine number of less than 10. 
     
     
         28 . The process of  claim 1 , wherein the solvent comprises natural gas liquid, light naphtha, or a blend of natural gas liquid and light naphtha. 
     
     
         29 . The process of  claim 1 , wherein the solvent comprises a C 1 -C 6  hydrocarbon liquid. 
     
     
         30 . The process of  claim 1 , wherein the solvent is used in a weight fraction of 0.1 to 0.3 based on oil sands weight. 
     
     
         31 . The process of  claim 1 , wherein the solvent is used in a weight fraction of 0.15 to 0.25 based on oil sands weight. 
     
     
         32 . The process of  claim 1 , wherein the extraction is effected with less than 100 ppmw caustic based on oil sands weight. 
     
     
         33 . The process of  claim 1 , wherein the extraction is effected in the absence of caustic as a means to assist extraction. 
     
     
         34 . The process of  claim 1 , wherein the extraction is effected in the absence of air as a means to separate bitumen droplets from the slurry. 
     
     
         35 . The process of  claim 1 , wherein a weight ratio of water to oil sands in the diluted extracted slurry is less than 2:1. 
     
     
         36 . The process of  claim 1 , wherein a weight ratio of water to oil sands in the diluted extracted slurry is less than 1.5:1. 
     
     
         37 . The process of  claim 1 , wherein a weight ratio of water to oil sands in the diluted extracted slurry is less than 1:1. 
     
     
         38 . The process of  claim 1 , wherein a weight ratio of water to oil sands in the diluted extracted slurry is at least 0.5:1. 
     
     
         39 . The process of  claim 1 , wherein a weight ratio of water to oil sands in the diluted extracted slurry is at least 0.7:1. 
     
     
         40 . The process of  claim 1 , wherein extraction is effected at a temperature of 10 to 50° C. 
     
     
         41 . The process of  claim 1 , wherein extraction is effected at a temperature of 25 to 35° C. 
     
     
         42 . The process of  claim 1 , wherein a solvent extraction residence time is at least 5 minutes. 
     
     
         43 . The process of  claim 1 , wherein a solvent extraction residence time is at least 10 minutes. 
     
     
         44 . The process of  claim 1 , wherein a water dilution residence time is at least 10 minutes. 
     
     
         45 . The process of  claim 1 , wherein a water dilution residence time is between 1 and 10 minutes. 
     
     
         46 . The process of  claim 1 , wherein a water dilution residence time is between 1 and 5 minutes. 
     
     
         47 . The process of  claim 1 , wherein the solvent is a solvent that will not precipitate asphaltenes. 
     
     
         48 . The process of  claim 1 , wherein the oil sands are mined oil sands that have been crushed. 
     
     
         49 . The process of  claim 1 , wherein the diluted bitumen extract is a non-emulsion.