Process for producing fuel

Abstract

A fuel is produced from bitumen by precipitating a substantial portion of asphaltenes from bitumen by contacting the bitumen with a lower alkane solvent. Suitable burners include a fluidized bed boiler, a circulating fluidized bed boiler and a pitch boiler which utilize either pre-combustion sulfur sorbents or post-combustion flue gas desulfurization. The sulfur in emissions can be used to produce sulfuric acid. The process uses a low cost fuel, generates steam, power and sulfuric acid and meets all emission requirements for SO 2, NO x and PM.

1 . A process for producing and using fuel from bitumen comprising the steps of 
 (a) precipitating a substantial portion of asphaltenes from bitumen by contacting the bitumen with a lower alkane solvent;    (b) using precipitated asphaltenes as a fuel in a boiler to generate high pressure steam and power; and    (c) cleaning emissions from the boiler to remove sulfur, NO x  and PM therefrom.    
     
     
         2 . The process of  claim 1 , wherein a gas and oil fraction of the bitumen is flashed out prior to step (a).  
     
     
         3 . The process of  claim 1 , wherein the bitumen is dehydrated and desalted.  
     
     
         4 . The process of  claim 1 , wherein the asphaltenes are liquid.  
     
     
         5 . The process of  claim 4 , wherein the liquid asphaltenes are pumpable.  
     
     
         6 . The process of  claim 1 , wherein the lower alkane solvent is selected from the group consisting of n-butane, n-pentane, n-hexane, n-heptane and mixtures thereof.  
     
     
         7 . The process of  claim 6 , wherein the lower alkane solvent is n-butane.  
     
     
         8 . The process of  claim 6 , wherein the lower alkane solvent is n-pentane.  
     
     
         9 . The process of  claim 1 , wherein the precipitated portion of asphaltene is from 5 to 40% w/w of the bitumen.  
     
     
         10 . The process of  claim 8 , wherein the precipitated asphaltene is from 15 to 25% of w/w of the bitumen.  
     
     
         11 . The process of  claim 1 , wherein a portion of a resin in the bitumen is precipitated with the asphaltenes.  
     
     
         12 . The process of  claim 11 , wherein the resin is less than 10% w/w of the bitumen.  
     
     
         13 . The process of  claim 1 , wherein the high pressure steam is used to produce electricity and steam for use in an oil sands extraction process.  
     
     
         14 . The process of  claim 13 , wherein said oil sands extraction process is a steam assisted gravity drainage, or a cyclic steam stimulation process.  
     
     
         15 . The process of  claim 1 , wherein the boiler is a fluidized bed boiler.  
     
     
         16 . The process of  claim 15 , wherein the boiler is a circulating fluidized bed boiler.  
     
     
         17 . The process of  claim 16 , wherein sulfur is removed from the boiler emissions using limestone or lime as a sulfur absorbent during combustion, by flue gas desulfurization or by a scrubber during post-combustion sulfur removal.  
     
     
         18 . The process of  claim 15 , wherein the boiler uses a device to produce sulfuric acid to remove SO 2  emissions.  
     
     
         19 . The process of  claim 2 , wherein the flashed out gas and oil fraction is mixed with de-asphalted oil obtained in step (a) to yield an upgraded de-asphalted oil of a lower viscosity, and lower density.