Apparatus and method for bitumen froth storage

Abstract

An apparatus and methodology for storing bitumen froth comprising a fluidized bottom, froth first feed holding tank for maintaining effective tank capacity while reducing overall solid bed build up at side walls and minimizing sloughing of solids to the froth discharge outlet. Froth is fed to the tank through one or more feed inlets located between the froth outlet and side walls for fluidizing settling solids. The feed inlets urge solids to settle in sub-beds about the feed inlets, the height of which that manifests adjacent the side walls being less that some design threshold height; if not, then successive feed inlets are located between the side walls and the precious feed inlets to build further sub-beds that have a height at the wall that is less than the threshold height.

The embodiments for which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A tank for holding froth from extracted oil sands, the froth containing at least bitumen and solids, the tank comprising:
 a side wall and a bottom wall forming an inner storage chamber having side walls,   one or more feed inlets located adjacent the bottom wall for introducing the froth upwardly into to the chamber,   an outlet located adjacent the bottom wall for removing froth from the chamber,   wherein the one or more feed inlets are located intermediate the outlet and the side walls, each feed inlet for fluidizing solids settling thereabout and forming a bed of solids about the feed inlet, each bed that reaches the side walls having a maximum height of less than a threshold height.   
     
     
         2 . The tank of  claim 1 , wherein the threshold height is that less than that capable of imposing a threshold loading on the side walls. 
     
     
         3 . The tank of  claim 1  wherein, when a height of a bed about a first feed inlet of the one or more feed inlets would reach the side wall at a height that exceeds the threshold height, one or more successive feed inlets are located intermediate the first feed inlet and the side walls. 
     
     
         4 . The tank of  claim 1 , wherein the bottom wall is generally horizontal. 
     
     
         5 . The tank of  claim 1 , wherein some of the one or more inlets may be positioned substantially at or near the bottom wall. 
     
     
         6 . The tank of  claim 5 , wherein some of the one or more inlets may be positioned through the bottom wall, through the side wall, or through an elevated inlet. 
     
     
         7 . The tank of  claim 1 , wherein the one or more feed inlets may comprise a plurality of inlets arranged in an array for fluidizing solids settling thereat and forming a plurality of sub-beds thereabout each one or more feed inlet. 
     
     
         8 . The tank of  claim 7 , wherein each sub-bed formed thereabout has a maximum height of less than a threshold height. 
     
     
         9 . The tank of  claim 7 , wherein the one or more inlets may be positioned to form one or more arrays of feed inlets spaced about and circumferentially about the outlet. 
     
     
         10 . The tank of  claim 9 , wherein the spacing of the one or more inlets minimizes sloughing of solids and prevents outlet blockage. 
     
     
         11 . The tank of  claim 1 , wherein the tank further comprises sloped directing elements for guiding settling solids in the chamber towards one or more of the feed inlets. 
     
     
         12 . The tank of  claim 11 , wherein one or more directing elements comprises at least one internal annular element projecting from the side walls for directing the solids away from the side walls. 
     
     
         13 . The tank of  claim 12 , wherein the at least one internal annular elements are vertically stacked within the chamber. 
     
     
         14 . The tank of  claim 11 , wherein the one or more directing elements comprise at least one transverse member extending across the chamber. 
     
     
         15 . The tank of  claim 14 , wherein the at least one transverse members are offset. 
     
     
         16 . The tank of  claim 11 , wherein the directing elements comprise at least one conical skirt encircling at least one of the one or more feed inlets for directing settling solids to the encircled feed inlet. 
     
     
         17 . The tank of  claim 11 , wherein the directing elements may comprise at least one internal annular element, at least one transverse member, at least one conical skirt or a combination thereof. 
     
     
         18 . A method for holding froth from extracted oil sands between froth processing stages is provided, the froth containing at least bitumen and solids, the method comprising:
 introducing the froth into a holding tank having side walls;   fluidizing the settling solids in the froth about one or more froth feed inlets located intermediate a discharge and the side walls such that the solids remain suspended in the froth about each feed inlet; and   settling solids about each of the one or more feed inlets to form one or more bed of solids, each bed reaching the side walls having a maximum height less than a threshold height.   
     
     
         19 . The method of  claim 18  wherein the one or more feed inlets are first feed inlets, and where beds about the first feed inlets reach the side walls having a maximum height greater than the threshold height, further comprising:
 locating one or more successive feed inlets between the first feed inlets and the side walls for fluidizing the settling solids in the froth about one or more successive feed inlets such that settling solids about each of the one or more successive feed inlets form one or more successive beds of solids, each successive bed reaching the side walls having a maximum height less than the threshold height.