Heat and water integration process for an oil sand operation with direct steam injection of warm thickener overlfow

Abstract

A heat and water integration process for an oil sands operation includes subjecting warm oil sands tailings to thickening to produce thickened tailings and warm water overflow; subjecting the warm water overflow to direct steam injection (DSI) to produce steam heated thickener water; providing the steam heated thickener water to a unit of the oil sand operation; and producing the warm oil sands tailings from the oil sands operation. The oil sand operation unit may be an oil sand ore preparation unit and/or a primary separation unit, for example. The heated thickener water can replace water taken from pond inventories. The DSI may use excess, low quality, wet, low pressure and/or blow-down steam. The process enables improved heat and water usage in oil sands processing.

1 . A heat and water integration process for an oil sands operation, comprising:
 subjecting a warm oil sands tailings stream to thickening to produce a thickened tailings component and a warm water overflow component;   subjecting at least a portion of the warm water overflow component to direct steam injection to produce a steam heated thickener water;   providing the steam heated thickener water to a unit of the oil sand operation; and   producing the warm oil sands tailings from the oil sands operation.   
     
     
         2 . The heat and water integration process of  claim 1 , wherein the unit of the oil sand operation is selected from (i) an oil sand ore preparation unit and (ii) a primary separation unit. 
     
     
         3 . The heat and water integration process of  claim 2 , wherein the primary separation unit receives an oil sand slurry and froth for separation and at least a portion of the steam heated thickener water is used as froth under-wash in the primary separation unit. 
     
     
         4 . The heat and water integration process of  claim 2 , wherein the oil sand ore preparation unit receives oil sand ore and at least a portion of the steam heated thickener water is used as hot slurrying medium in the oil sand ore preparation unit. 
     
     
         5 . The heat and water integration process of  claim 1 , comprising supplying ambient recycle water from a pond to the unit of the oil sands operation. 
     
     
         6 . The heat and water integration process of  claim 5 , comprising combining a portion of the ambient recycle water with a portion of the warm water overflow component to produce a warm process water stream and supplying the warm process water stream to an oil sand ore preparation unit. 
     
     
         7 . The heat and water integration process of  claim 5 , comprising heating a portion of the ambient recycle water in a heat exchanger to produce a heated recycle water and supplying the heated process water to an oil sand ore preparation unit. 
     
     
         8 . The heat and water integration process of  claim 5 , comprising heating a portion of the ambient recycle water in a heat exchanger to produce a heated recycle water and supplying the heated process water to a primary separation unit. 
     
     
         9 . The heat and water integration process of  claim 8 , wherein the wherein the primary separation unit receives an oil sand slurry and froth for separation and at least a portion of the steam heated thickener water and the heated recycle water are combined and used as froth under-wash in the primary separation unit. 
     
     
         10 . The heat and water integration process of  claim 7 , comprising:
 providing steam from a central steam source;   using a first portion of the steam in the direct steam injection; and   using a second portion of the steam for heating the ambient recycle water in the heat exchanger.   
     
     
         11 . The heat and water integration process of  claim 5 , wherein the warm water overflow component has a temperature between about 20° C. and about 45° C. higher than the recycle pond water. 
     
     
         12 . The heat and water integration process of  claim 1 , wherein the direct steam injection heats the warm water overflow component from an initial temperature between about 20° C. and about 50° C. to a temperature of the steam heated thickener overflow between about 70° C. and about 90° C. 
     
     
         13 . The heat and water integration process of  claim 12 , wherein the temperature of the steam heated thickener overflow is between about 75° C. and about 85° C. 
     
     
         14 . The heat and water integration process of any one of  claims 1  to  13 , wherein the direct steam injection has a steam input between about 20 to 90 kG/t of oilsand. 
     
     
         15 . The heat and water integration process of  claim 14 , wherein the steam input is between about 150 tonnes/hr and about 300 tonnes/hr. 
     
     
         16 . The heat and water integration process of  claim 1 , wherein the direction steam injection comprises maintaining sufficient backpressure on the steam heated thickener water downstream of the direction steam injection so as to sub-cool the warm water overflow component. 
     
     
         17 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses steam selected from the group consisting of excess steam, low quality steam, wet steam, low pressure steam and blow-down steam. 
     
     
         18 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses steam having a pressure at least 45 psia. 
     
     
         19 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses steam containing non-condensable gases. 
     
     
         20 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses saturated steam. 
     
     
         21 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses steam generated by a low pressure boiler. 
     
     
         22 . The heat and water integration process of  claim 1 , wherein the direction steam injection uses steam generated from condensate blowdown. 
     
     
         23 . The heat and water integration process of  claim 1 , comprising providing a knock-out or steam trap system upstream of the direction steam injection. 
     
     
         24 . The heat and water integration process of  claim 1 , wherein the process is conducted at least in wintertime. 
     
     
         25 . A process for producing bitumen, comprising:
 subjecting oil sands ore to extraction operations using hot extraction water, in order to produce bitumen and a warm oil sands tailings stream;   subjecting the warm oil sands tailings stream to thickening to produce a thickened tailings component and a warm water overflow component;   subjecting at least a portion of the warm water overflow component to direct steam injection to produce a steam heated thickener water; and   providing the steam heated thickener water to the extraction operations as part of the hot extraction water.