Continuous flow separation and aqueous solution treatment for recovery of crude oil from tar sands

Abstract

Process and apparatus for the continuous separation of crude oil from tar sands include using a hydrocarbon diluent and an aqueous solution in one or more settling vessels. The light components from the oil are collected and recycled to be used as the hydrocarbon diluent, and the aqueous solution is collected and recycled. A second aqueous solution is introduced in the second and subsequent vessels to prevent the formation of an oil film on the equipment.

1 . A method for recovering oil from a material containing oil, comprising:
 treating the material with an aqueous solution comprising a wetting agent and a specific gravity enhancing agent to achieve a pH in the range of about 11.2 to about 12.0 and a specific gravity in the range of about 1.07 to about 1.01; and   collecting oil that separates from the material.   
     
     
         2 . The method of  claim 1 , wherein the temperature is in the range of about 40° F. to about 100° F. 
     
     
         3 . The method of  claim 1 , wherein the wetting agent comprises sodium metasilicate pentahydrate. 
     
     
         4 . The method of  claim 1 , wherein the specific gravity enhancing agent comprises soda ash. 
     
     
         5 . The method of  claim 1 , comprising treating the tar sands in a first treating step with a first aqueous solution of sodium metasilicate pentahydrate, soda ash, and sodium bicarbonate, collecting the treated sand after the oil has been separated, then treating the sand in a second treating step with a second aqueous solution of sodium metasilicate pentahydrate and sodium carbonate. 
     
     
         6 . The method of  claim 5 , wherein the first aqueous solution comprises about 9×10 −6  to 3×10 −5  weight fraction of sodium metasilicate pentahydrate, about 9×10 −7  to 3×10 −6  weight fraction of soda ash, less than 3×10 −6  weight fraction of sodium bicarbonate, and water. 
     
     
         7 . The method of  claim 5 , wherein the second aqueous solution comprises 1.8×10 −7  to 8×10 −6  weight fraction of sodium metasilicate pentahydrate, about 1.8×10 −6  to 3.6×10 −6  weight fraction soda ash, and water. 
     
     
         8 . The method of  claim 1 , comprising treating tar sands with a hydrocarbon diluent before treating with the aqueous solution. 
     
     
         9 . The method of  claim 1 , comprising separating a hydrocarbon diluent from the tar sands and treating tar sands with the diluent. 
     
     
         10 . A method for recovering oil from a material containing oil, comprising:
 treating the material with an aqueous solution, wherein said treatment is at a pH in the range of about 11.2 to about 12.0 and at a specific gravity in the range of about 1.07 to about 1.01; and   collecting oil that separates from the material.   
     
     
         11 . A method for separating oil from material containing oil, comprising:
 adding a hydrocarbon diluent and a first aqueous solution to material containing oil;   separating light components of the oil from the material;   recycling the light components to use as the diluent; and   separating oil from the material in one or more settling vessels that allow the oil to rise above the aqueous solution in the vessel and the material to settle to the bottom of the vessel.   
     
     
         12 . The method of  claim 11 , further comprising applying a mist of the hydrocarbon diluent on the material in a pressurized hopper to reduce the internal fluid friction or viscosity to soften the oil layers surrounding each particle of material containing the oil. 
     
     
         13 . The method of  claim 11 , wherein the material is transferred in the hopper via one or more inclined screw conveyors. 
     
     
         14 . The method of  claim 11 , wherein the first aqueous solution is recovered and reused in treating the material. 
     
     
         15 . The method of  claim 11 , further comprising treating the material with the first aqueous solution within a line leading to a first settling vessel. 
     
     
         16 . The method of  claim 15 , further comprising collecting the light components of the oil from the settling vessel and reusing as the hydrocarbon diluent. 
     
     
         17 . The method of  claim 15 , further comprising collecting more than one fraction of oil components from the settling vessel based on the specific gravity of the components. 
     
     
         18 . The method of  claim 15 , further comprising collecting the material that settles to the bottom of the settling vessel and adding a second aqueous solution to the material and transferring the material and second aqueous solution to a second settling vessel to separate more than one fraction of oil components based on the specific gravity of the components. 
     
     
         19 . The method of  claim 18 , further comprising collecting the second aqueous solution and reusing the second aqueous solution in treating the material. 
     
     
         20 . The method of  claim 18 , wherein the second aqueous solution comprises 1.8×10 −7  to 8×10 −6  weight fraction of sodium metasilicate pentahydrate, about 1.8×10 −6  to 3.6×10 −6  weight fraction soda ash, and water. 
     
     
         21 . The method of  claim 11 , wherein the first aqueous solution comprises about 9×10 −6  to 3×10 −5  weight fraction of sodium metasilicate pentahydrate, about 9×10 −7  to 3×10 −6  weight fraction of soda ash, less than 3×10 −6  weight fraction of sodium bicarbonate, and water. 
     
     
         22 . The method of  claim 11 , comprising treating material in a first and second settling vessel, wherein the first aqueous solution is used to treat the material in the first settling vessel and a second and different aqueous solution is used to treat the material in the second settling vessel. 
     
     
         23 . The method of  claim 22 , further comprising collecting the lightest fraction from the first settling vessel and separating the hydrocarbon diluent and the first aqueous solution from said lightest fraction. 
     
     
         24 . The method of  claim 22 , further comprising collecting the second lightest fraction from the first and second settling vessels and separating the hydrocarbon diluent, crude oil, the first aqueous solution, and the material from said second lightest fraction. 
     
     
         25 . The method of  claim 11 , wherein the material is sand or crushed shale. 
     
     
         26 . The method of  claim 11 , wherein the conditions in the one or more settling vessels include a pH in the range of about 11.2 to about 12.0 and a specific gravity in the range of about 1.07 to about 1.01. 
     
     
         27 . The method of  claim 26 , wherein the temperature in the one or more settling vessels is in the range of about 40° F. to about 100° F. 
     
     
         28 . A method for the separation of crude oil from tar sands, comprising:
 treating tar sands with a first aqueous solution of sodium metasilicate and soda ash, and optionally sodium bicarbonate to separate the crude oil from the tar sands; and   treating the tar sands with a second aqueous solution of sodium metasilicate and soda ash, wherein the second aqueous solution has a lower concentration of sodium metasilicate and soda ash than the first aqueous solution.