Bitumen froth treating process

Abstract

A process for treating a bitumen froth containing bitumen, solid mineral material and water, including subjecting a first mixture containing the bitumen froth and a first amount of a paraffinic solvent to first gravity separation, thereby producing a first overflow stream and a first underflow stream, wherein the first gravity separation is performed so that the first underflow stream contains between about 5 percent and about 40 percent by weight of the asphaltenes contained in the first mixture. A second mixture containing the first underflow stream and a second amount of the paraffinic solvent is subjected to second gravity separation in order to recover bitumen from the first underflow stream.

1 . A process for treating a bitumen froth comprising bitumen, solid mineral material and water, the process comprising:
 (a) subjecting a first mixture comprising the bitumen froth and a first amount of a paraffinic solvent to first gravity separation in a first gravity separation apparatus, thereby producing a first overflow stream and a first underflow stream, wherein the first mixture has a first solvent to bitumen ratio, wherein the first mixture is comprised of first mixture asphaltenes, and wherein the first gravity separation is performed so that the first underflow stream is comprised of between 5 percent and 40 percent of the first mixture asphaltenes by weight; and   (b) subjecting a second mixture comprising the first underflow stream and a second amount of the paraffinic solvent to second gravity separation in a second gravity separation apparatus, wherein the second mixture has a second solvent to bitumen ratio and wherein the second solvent to bitumen ratio is greater than the first solvent to bitumen ratio, thereby producing a second overflow stream and a second underflow stream.   
   
   
       2 . The process as claimed in  claim 1  wherein the first overflow stream is comprised of less than or equal to 0.5 percent solid mineral material and water by weight. 
   
   
       3 . The process as claimed in  claim 1  wherein the first gravity separation is performed so that the first underflow stream is comprised of between 5 percent and 25 percent of the first mixture asphaltenes by weight. 
   
   
       4 . The process as claimed in  claim 1 , further comprising adding the second overflow stream to the first mixture so that the first mixture is comprised of the bitumen froth, the first amount of the paraffinic solvent, and the second overflow stream. 
   
   
       5 . The process as claimed in  claim 4  wherein the second overflow stream is comprised of the paraffinic solvent so that the first amount of the paraffinic solvent is provided by the second overflow stream. 
   
   
       6 . The process as claimed in  claim 4  wherein the first overflow stream is comprised of less than or equal to 0.5 percent by weight solid mineral material and water. 
   
   
       7 . The process as claimed in  claim 4  wherein the first underflow stream is comprised of between 5 percent and 25 percent of the first mixture asphaltenes by weight. 
   
   
       8 . The process as claimed in  claim 1  wherein the first gravity separation apparatus is comprised of an inclined plate settler. 
   
   
       9 . The process as claimed in  claim 8  wherein the second gravity separation apparatus is comprised of a gravity settling vessel. 
   
   
       10 . The process as claimed in  claim 8  wherein the first overflow stream is comprised of less than or equal to 0.5 percent by weight solid mineral material and water. 
   
   
       11 . The process as claimed in  claim 8  wherein the first gravity separation is performed so that the first underflow stream is comprised of between 5 percent and 25 percent of the first mixture asphaltenes by weight. 
   
   
       12 . The process as claimed in  claim 1 , further comprising subjecting a third mixture comprising the second underflow stream and a third amount of the paraffinic solvent to third gravity separation in a third gravity separation apparatus, wherein the third mixture has a third solvent to bitumen ratio and wherein the third solvent to bitumen ratio is greater than the first solvent to bitumen ratio, thereby producing a third overflow stream and a third underflow stream. 
   
   
       13 . The process as claimed in  claim 12 , further comprising adding the third overflow stream to the second mixture so that the second mixture is comprised of the first underflow stream, the second amount of the paraffinic solvent, and the third overflow stream. 
   
   
       14 . The process as claimed in  claim 13  wherein the third overflow stream is comprised of the paraffinic solvent so that the second amount of the paraffinic solvent is provided by the third overflow stream. 
   
   
       15 . The process as claimed in  claim 13  wherein the first overflow stream is comprised of less than or equal to 0.5 percent solid mineral material and water by weight. 
   
   
       16 . The process as claimed in  claim 13  wherein the first gravity separation is performed so that the first underflow stream is comprised of between 5 percent and 25 percent of the first mixture asphaltenes by weight. 
   
   
       17 . The process as claimed in  claim 13  wherein the first gravity separation apparatus is comprised of an inclined plate settler. 
   
   
       18 . The process as claimed in  claim 17  wherein the second gravity separation apparatus is comprised of a gravity settling vessel. 
   
   
       19 . The process as claimed in  claim 17  wherein the third gravity separation apparatus is comprised of a gravity settling vessel. 
   
   
       20 . The process as claimed in  claim 17  wherein the first overflow stream is comprised of less than or equal to 0.5 percent solid mineral material and water by weight. 
   
   
       21 . The process as claimed in  claim 17  wherein the first gravity separation is performed so that the first underflow stream is comprised of between 5 percent and 25 percent of the first mixture asphaltenes by weight. 
   
   
       22 . The process as claimed in  claim 1  wherein the paraffinic solvent is comprised of a paraffinic compound selected from the group of paraffinic compounds consisting of butane, pentane, hexane, heptane, octane and mixtures thereof. 
   
   
       23 . The process as claimed in  claim 1  wherein the paraffinic solvent is comprised of a mixture of pentane and hexane. 
   
   
       24 . The process as claimed in  claim 1  wherein the paraffinic solvent is comprised of one or more natural gas liquids.