Feed delivery system for a froth settling unit

Abstract

Embodiments of a feedwell discharge a solvent treated bitumen-containing froth feed to a froth settling vessel at a Richardson number less than 1.0. Feed is discharged from feedwell inlets to the vessel, either located at a center of the vessel or at a perimeter wall of the vessel along a substantially horizontal path across the vessel. The high velocity maximizes the horizontal path. As the velocity is reduced along the path and as a result of collision in the vessel with the perimeter wall or with feed entering the vessel from an opposing inlet, the feed separates into diluted bitumen and solvent which rises in the vessel for discharge as an overflow product and a waste stream, comprising water, solids and asphaltenes, which settles to the bottom of the vessel to be discharged as an underflow. A relatively uniform clarification zone forms above the inlets submerged in the vessel.

The embodiments in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A method for treating a bitumen-containing, paraffinic froth feed containing a solvent-diluted bitumen, water, solids and asphaltenes in a froth settling vessel comprising:
 delivering the feed to a separation zone within the vessel;   discharging the feed into the separation zone, through one or more inlets, each inlet discharging the feed at a high velocity for forming a coherent stream along a flow path generally horizontally toward a boundary and having a Richardson number less than about unity for maximizing the flow path in the separation zone, the flow velocity of the flow path dissipating adjacent the boundary for separating the feed into a diluted bitumen and solvent product which rises to a top of the vessel and a waste stream comprising water, solids and asphaltenes which settles by gravity to a bottom of the vessel.   
     
     
         2 . The method of  claim 1  wherein un-coalesced water droplets are carried above the separation zone, the method further comprising:
 coalescing of the un-coalesced water droplets in a coalescing zone above the separation zone, wherein the coalesced water droplets fall by gravity through the separation zone, to settle at the bottom of the vessel, carrying suspended solids associated therewith. 
 
     
     
         3 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises discharging the feed at a Richardson number between about 0.001 to about 0.8. 
     
     
         4 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises discharging the feed at a Richardson number between about 0.001 to about 0.5. 
     
     
         5 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises discharging the feed at a Richardson number between about 0.001 to about 0.125. 
     
     
         6 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises:
 discharging the feed through one or more inlets in, at or adjacent a perimeter wall of the vessel and normal thereto for directing the coherent stream of feed on the horizontal path toward the boundary adjacent a center of the vessel. 
 
     
     
         7 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises:
 discharging the feed through one or more inlets in, at or adjacent a perimeter wall of the vessel and angled relative thereto for directing the coherent stream of feed on the horizontal path and in a circular flow pattern within the vessel toward the boundary. 
 
     
     
         8 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises:
 discharging the feed through one or more inlets fluidly connected to an inlet pipe extending into the vessel along an axis of the vessel for directing the coherent stream of feed horizontally outwardly therefrom on the horizontal path, wherein the boundary is a perimeter wall of the vessel. 
 
     
     
         9 . The method of  claim 1  wherein the discharging the feed into the separation zone further comprises:
 discharging the feed through one or more inlets fluidly connected to an inlet pipe extending into the vessel along an axis of the vessel, the one or more inlets being angled relative to the inlet pipe for directing the feed on the horizontal path and in a circular flow pattern within the vessel toward the boundary. 
 
     
     
         10 . The method of  claim 1  further comprising:
 positioning the one or more inlets at a height in the vessel wherein a height of a cylindrical portion thereabove is about equivalent to a diameter of the vessel. 
 
     
     
         11 . The method of  claim 1  further comprising:
 positioning the one or more inlets in the vessel wherein the inlets are immersed in fluid contained within the vessel wherein the fluid contains about 60% of an aqueous phase and about 40% of a hydrocarbon phase. 
 
     
     
         12 . A system for separating a feed into a diluted bitumen and solvent product stream and a waste stream comprising:
 a settling vessel having an upper cylindrical portion and a conical bottom portion, the product stream being discharged as an overflow therefrom and the waste steam being discharged as an underflow therefrom; and   a feedwell, having one or more inlets to the vessel, delivering the feed to a separation zone within the vessel for discharging the feed into the separation zone through one or more inlets, each inlet discharging the feed at a high velocity, having a Richardson number less than about unity, for forming a coherent stream along a flow path generally horizontally toward a boundary for maximizing the flow path in the separation zone, the velocity dissipating at about the boundary for separating the feed into the product stream which rises to a top of the vessel and the waste stream comprising water, solids and asphaltenes which settles by gravity to a bottom of the vessel.   
     
     
         13 . The system of  claim 12  wherein the coherent stream further comprises un-coalesced water droplets which are carried above the separation zone; the system further comprising:
 a coalescing zone formed above the separation zone wherein the un-coalesced water droplet coalesce, the coalesced water droplets thereafter falling by gravity through the separation zone as a result of increased diameter and terminal downward velocity, to settle at the bottom of the vessel, carrying suspended solids associated therewith. 
 
     
     
         14 . The system of  claim 12  wherein the feed is discharged into the separation zone at a Richardson number between about 0.001 to about 0.8. 
     
     
         15 . The system of  claim 12  further wherein the feed is discharged into the separation zone at a Richardson number between about 0.001 to about 0.5. 
     
     
         16 . The system of  claim 12  wherein the feed is discharged into the separation zone a Richardson number between about 0.001 to about 0.125. 
     
     
         17 . The system of  claim 12  wherein the one or more inlets are submerged within the separation zone, a height of the cylindrical portion thereabove being about equivalent to a diameter of the vessel. 
     
     
         18 . The system of  claim 12  wherein the one or more inlets are immersed in fluid contained within the vessel wherein the fluid contains about 60% of an aqueous phase and about 40% of a hydrocarbon phase. 
     
     
         19 . The system of  claim 12  wherein the feedwell further comprises:
 an inlet pipe extending within the vessel along an axis of the vessel, the inlet pipe being fluidly connected to the one or more inlets to the vessel. 
 
     
     
         20 . The system of  claim 19  wherein the one or more inlets are fluidly connected to a distal end of the inlet pipe and extend radially outwardly therefrom for discharging the feed along the generally horizontal path toward a perimeter wall of the vessel. 
     
     
         21 . The system of  claim 19  wherein the one or more inlets extend normal to the inlet pipe. 
     
     
         22 . The system of  claim 19  wherein the one or more inlets are angled or tangential to the inlet pipe for discharging the feed along the generally horizontal path in a circular flow pattern. 
     
     
         23 . The system of  claim 19  wherein the one or more inlets are in, at or spaced from a perimeter wall of the vessel and extend radially inwardly therefrom for discharging the feed toward a center of the vessel. 
     
     
         24 . The system of  claim 23  wherein the one or more inlets extend normal to the perimeter wall. 
     
     
         25 . The system of  claim 23  wherein the one or more inlets are angled or tangential to the perimeter wall for discharging the feed along the generally horizontal path in a circular flow pattern. 
     
     
         26 . The system of  claim 23  further comprising:
 an inlet pipe extending into the vessel along an axis of the vessel; 
 one or more radially outwardly extending pipes connected to a distal end of the inlet pipe; 
 one or more downwardly extending pipes fluidly connected to the one or more radially outwardly extending pipes and extending at or adjacent the perimeter wall of the vessel, 
 wherein the one or more downwardly extending pipes are fluidly connected at a distal end to the one or more inlets and the one or more inlets extend radially inwardly therefrom for discharging the feed therefrom toward a center of the vessel. 
 
     
     
         27 . The system of  claim 26  wherein the one or more inlets extend normal to the inlet pipe. 
     
     
         28 . The system of  claim 26  wherein the one or more inlets are angled or tangential to the inlet pipe for discharging the feed along the generally horizontal path in a circular flow pattern.