Enhanced temperature control of bitumen froth treatment process

Abstract

A method for pre-treating bitumen froth for mixing with solvent for froth treatment includes heating the froth to a froth-solvent mixing temperature below the solvent flash temperature and suitably high to provide reduced bitumen viscosity sufficiently low for complete mixing of the solvent and the froth prior to introduction into a separation apparatus. A method of improving energy use in froth treatment includes reducing heat provided to the solvent, increasing heat provided to the froth prior to adding the solvent to reduce bitumen viscosity and adding the temperature-reduced solvent to the heated froth. A froth treatment separation process includes trim heating first and second solvent streams to adjust the first and second stage separation temperatures.

1 . A method for pre-treating bitumen containing froth for mixing with a paraffinic solvent containing stream to produce a diluted froth for introduction into a separation apparatus for separation into a diluted bitumen component and a solvent diluted tailings component, the method comprising heating the bitumen froth to produce a heated froth with a reduced viscosity and a froth-solvent mixing temperature that is below a flash temperature of the solvent and ranging from about 75° C. to about 95° C., the heated bitumen froth viscosity being at most about 700 cP higher than a solvent stream viscosity. 
     
     
         2 . The method of  claim 1 , wherein the bitumen froth has a bitumen content between about 40 wt % and about 75 wt %. 
     
     
         3 . The method of  claim 2 , comprising adapting the heating of the bitumen froth in accordance with the bitumen content thereof. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the heating is conducted by direct steam injection. 
     
     
         6 .- 9 . (canceled) 
     
     
         10 . The method of  claim 1 , wherein the heating is conducted to cause formation of bitumen droplets having a maximum droplet size d max  of about 100 μm. 
     
     
         11 . The method of  claim 1 , wherein the heating is conducted to cause formation of bitumen droplets having a maximum droplet size d max  between about 100 μm and about 25 μm. 
     
     
         12 . The method of  claim 1 , wherein the heating is conducted to control the reduced bitumen viscosity of at most about 650 cP. 
     
     
         13 . The method of  claim 1 , wherein the heating is conducted to control the reduced bitumen viscosity between about 100 cP and about 650 cP. 
     
     
         14 . The method of  claim 1 , wherein the heating is conducted to provide the reduced bitumen viscosity between about 1.5 times and about 100 times lower than the viscosity of the bitumen in the froth. 
     
     
         15 . The method of  claim 1 , wherein the heating is conducted to control the froth-solvent mixing temperature at least about 10° C. below the flash temperature of the solvent. 
     
     
         16 . The method of  claim 1 , wherein the heating is conducted to reduce a bitumen/solvent viscosity ratio by at least about an order of magnitude. 
     
     
         17 . The method of  claim 1 , wherein the heating is conducted to control the froth-solvent mixing temperature above a temperature of the solvent. 
     
     
         18 . The method of  claim 17 , wherein the froth-solvent mixing temperature is at least about 10° C. above the temperature of the solvent. 
     
     
         19 . The method of  claim 1 , wherein the separation apparatus comprises a first stage separation vessel and a second stage separation vessel in counter-current configuration. 
     
     
         20 . The method of  claim 19 , comprising:
 supplying the diluted froth to the first stage separation vessel and producing the diluted bitumen component and a first stage underflow component;   adding a make-up solvent stream to the first stage underflow component to produce a diluted first stage underflow;   supplying the diluted first stage underflow to the second stage separation vessel and producing the a second stage overflow component and a second stage underflow component as the solvent diluted tailings component; and   supplying the second stage overflow component as the solvent containing stream added to the heated froth.   
     
     
         21 . The method of  claim 20 , comprising trim heating the solvent containing stream to control temperatures of the diluted froth and the first stage separation vessel. 
     
     
         22 . The method of  claim 20 , comprising trim heating the make-up solvent stream to control temperatures of the diluted first stage underflow to the second stage separation vessel. 
     
     
         23 . The method of  claim 20 , comprising maintaining a first operating temperature of the first stage separation vessel above a second operating temperature of the second stage separation vessel. 
     
     
         24 . The method of  claim 20 , comprising providing the make-up solvent stream cooler than the solvent containing stream added to the heated froth. 
     
     
         25 . The method of  claim 1 , comprising subjecting the solvent diluted tailings component to solvent recovery flashing and operating the second stage separation vessel such that the solvent diluted tailings component has a temperature suitable for the solvent recovery flashing. 
     
     
         26 . A method of improving energy use in a froth treatment operation, the froth treatment operation comprising adding a paraffinic solvent containing stream to bitumen froth to produce a diluted froth, introducing the diluted froth into a separation apparatus and producing from the separation apparatus a diluted bitumen component and a solvent diluted tailings component, the method comprising:
 reducing heat provided to the solvent containing stream thereby producing a temperature-reduced solvent stream;   increasing heat provided to the bitumen froth prior to adding the solvent containing stream thereto to produce a heated froth with a froth-solvent mixing temperature that is below a flash temperature of the solvent and suitably high to provide a reduced bitumen viscosity;   adding the temperature-reduced solvent to the heated froth and thereby producing the diluted froth for separation.   
     
     
         27 . The method of  claim 26 , wherein the bitumen froth has a bitumen content between about 40 wt % and about 75 wt %. 
     
     
         28 . The method of  claim 27 , comprising adapting the heating of the bitumen froth in accordance with the bitumen content thereof. 
     
     
         29 . (canceled) 
     
     
         30 . The method of  claim 26 , wherein the heating is conducted by direct steam injection. 
     
     
         31 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature above about 60° C. 
     
     
         32 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature above about 70° C. 
     
     
         33 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature above about 90° C. 
     
     
         34 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature in between about 90° C. and about 120° C. 
     
     
         35 . The method of  claim 26 , wherein the heating is conducted to cause formation of bitumen droplets having a maximum droplet size d max  of at most about 100 μm. 
     
     
         36 . The method of  claim 26 , wherein the heating is conducted to cause formation of bitumen droplets having a maximum droplet size d max  in between about 100 μm and about 25 μm. 
     
     
         37 . The method of  claim 26 , wherein the heating is conducted to control the reduced bitumen viscosity of at most about 650 cP. 
     
     
         38 . The method of  claim 26 , wherein the heating is conducted to control the reduced bitumen viscosity in between about 100 cP and about 650 cP. 
     
     
         39 . The method of  claim 26 , wherein the heating is conducted to provide the reduced bitumen viscosity between about 1.5 times and about 100 times lower than the viscosity of the bitumen in the froth. 
     
     
         40 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature at least about 10° C. below the flash temperature of the solvent. 
     
     
         41 . The method of  claim 26 , wherein the heating is conducted to reduce a bitumen/solvent viscosity ratio by at least about an order of magnitude. 
     
     
         42 . The method of  claim 26 , wherein the heating is conducted to control the froth-solvent mixing temperature above a temperature of the solvent. 
     
     
         43 . The method of  claim 42 , wherein the froth-solvent mixing temperature is at least about 10° C. above the temperature of the solvent. 
     
     
         44 . The method of  claim 26 , wherein the separation apparatus comprises a first stage separation vessel and a second stage separation vessel in counter-current configuration. 
     
     
         45 . The method of  claim 44 , comprising:
 supplying the diluted froth to the first stage separation vessel and producing the diluted bitumen component and a first stage underflow component;   adding a make-up solvent stream to the first stage underflow component to produce a diluted first stage underflow;   supplying the diluted first stage underflow to the second stage separation vessel and producing the a second stage overflow component and a second stage underflow component as the solvent diluted tailings component; and   supplying the second stage overflow component as the solvent containing stream added to the heated froth.   
     
     
         46 . The method of  claim 45 , comprising trim heating the solvent containing stream to control temperatures of the diluted froth and the first stage separation vessel. 
     
     
         47 . The method of  claim 45 , comprising trim heating the make-up solvent stream to control temperatures of the diluted first stage underflow to the second stage separation vessel. 
     
     
         48 . The method of  claim 45 , comprising maintaining a first operating temperature of the first stage separation vessel above a second operating temperature of the second stage separation vessel. 
     
     
         49 . The method of  claim 45 , comprising providing the make-up solvent stream cooler than the solvent containing stream added to the heated froth. 
     
     
         50 . The method of  claim 26 , comprising subjecting the solvent diluted tailings component to solvent recovery flashing and operating the second stage separation vessel such that the solvent diluted tailings component has a temperature suitable for the solvent recovery flashing. 
     
     
         51 . A process for separating a bitumen froth into a diluted bitumen component and a diluted tailings component, the process comprising:
 adding a first solvent containing stream to the bitumen froth to produce a diluted bitumen froth, the first solvent-containing stream having a first solvent temperature and the bitumen froth having a froth temperature;   separating the diluted bitumen froth into a first stage overflow component and a first stage underflow component having an underflow temperature, wherein the first stage overflow component comprises the diluted bitumen component;   adding a second solvent containing stream to the first stage underflow component to produce a diluted first stage underflow component, the second solvent containing stream having a second solvent temperature;   separating the diluted first stage underflow component into a second stage overflow component and a second stage underflow component, wherein the second stage underflow component comprises the diluted tailings component;   trim heating the first solvent containing stream to adjust the first solvent temperature to maintain consistent first stage separation temperature; and   trim heating the second solvent containing stream to adjust the second solvent temperature to maintain consistent second stage separation temperature.   
     
     
         52 . The process of  claim 51 , wherein the froth temperature is at least 65° C. 
     
     
         53 . The process of  claim 51 , wherein the froth temperature is controlled between about 70° C. and about 120° C. 
     
     
         54 . The process of  claim 51 , wherein the froth temperature is controlled at above 90° C. 
     
     
         55 . The process of  claim 51 , wherein the first stage separation temperature is maintained above the second stage separation temperature. 
     
     
         56 . The process of  claim 51 , wherein the bitumen froth is preheated before the adding of the first solvent containing stream to the bitumen froth. 
     
     
         57 . The process of  claim 51 , wherein the trim heating of the first and second solvent containing streams are performed with heat exchangers. 
     
     
         58 . The process of  claim 51 , wherein the solvent is a naphthenic solvent. 
     
     
         59 . The process of  claim 51 , wherein the solvent is a paraffinic solvent.