Process for treating a hydrocarbon-based heavy residue

Abstract

The process for treating a hydrocarbon-based heavy residue ( 1 ), in particular bituminous residues with a high asphaltene content, comprises the following operations: A) bringing the heavy residue to be treated to a temperature within the range of 325-500° C.; B) subjecting the heavy residue to be treated to a substantially adiabatic expansion in an environment at a pressure equal to or lower than about 0.1 bara, and at a temperature equal to or lower than 450° C., so as to separate, from the heavy residue to be treated, a first less volatile fraction ( 17 ) having a boiling point at atmospheric pressure equal to or higher than 540° C. and whose solid and/or anhydrous residue prevalently contains asphaltenes insoluble in pentane and/or other residues insoluble in tetrahydrofuran. It allows a more effective flushing, and also to actuate the process in an extremely simple plant and without centrifugations.

1 . A process for treating a heavy hydrocarbon-based residue, comprising:
 bringing the heavy hydrocarbon-based residue to a temperature of 325-500° C.;   subjecting the heavy hydrocarbon-based residue to a substantially adiabatic expansion in an environment having a pressure equal to or lower than about 0.1 bara and at a temperature equal to or lower than 450° C. to separate a first less volatile fraction and a second more volatile fraction from the heavy hydrocarbon-based residue;   wherein:   the first less volatile fraction has a boiling point of equal to or higher than 540° C. at atmospheric pressure and comprises a solid and/or an anhydrous residue comprising asphaltenes insoluble in pentane; and optionally other residues insoluble in tetrahydrofuran; and   the second more volatile fraction comprising maltenes and other hydrocarbons having a boiling point equal to or lower than 540° C. at atmospheric pressure.   
     
     
         2 . The process according to  claim 1 , wherein the heavy hydrocarbon-based residue is a bituminous residue comprising 20% to 45% by weight of C5-asphaltenes and 10% to 20% by weight of tetrahydrofurans. 
     
     
         3 . The process according to  claim 1 , further comprising:
 expanding the heavy hydrocarbon-based residue starting from a pressure of higher than 1 bara.   
     
     
         4 . The process according to  claim 3 , wherein the heavy hydrocarbon-based residue is expanded starting from a pressure of 1-2 bara. 
     
     
         5 . The process according to  claim 1 , wherein the adiabatic expansion is substantially instantaneous. 
     
     
         6 . The process according to  claim 1 , further comprising:
 effecting the adiabatic expansion by passing the hydrocarbon-based residue through a lamination valve.   
     
     
         7 . The process according to  claim 1 , wherein the heavy hydrocarbon-based residue comprises at least 30% by weight of asphaltenes insoluble in pentane and optionally other residues insoluble in pentane and/or tetrahydrofuran. 
     
     
         8 . The process according to  claim 7 , wherein the heavy hydrocarbon-based residue comprises 20% to 45% by weight of C5-asphaltenes and 10% to 20% by weight of tetrahydrofurans. 
     
     
         9 . The process according to  claim 1 , wherein the first less volatile fraction has a total content of asphaltenes of 75% to 94% by weight and a total content of maltenes and other lighter hydrocarbons of 6% to 25% by weight. 
     
     
         10 . The process according to  claim 1 , further comprising:
 obtaining the heavy hydrocarbon-based residue to be treated by converting heavy oils into lower-molecular-weight substances, subjecting the heavy oils to hydrocracking optionally in the presence of catalysts.   
     
     
         11 . The process according to  claim 10 , wherein the hydrocracking is effected by bubbling hydrogen into the heavy oils or other hydrocarbon-based substances. 
     
     
         12 . The process according to  claim 1 , further comprising:
 fluidifying the heavy hydrocarbon-based residue by introducing a stream of water vapor or other gaseous substance into the heavy hydrocarbon-based residue.   
     
     
         13 . The process according to  claim 12 , wherein the ratio between the water vapor or the other gaseous substance and the flow-rate of the heavy hydrocarbon-based residue is 0.03 to 0.75 by volume. 
     
     
         14 . The process according to  claim 1 , further comprising:
 effecting the substantially adiabatic expansion in a separator comprising a container, and   collecting, on the bottom of said container, the first less volatile fraction.   
     
     
         15 . The process according to  claim 1 , further comprising:
 depositing the first less volatile fraction on a cooled conveyor belt having a surface temperature of equal to or lower than 100° C.   
     
     
         16 . The process according to  claim 15 , further comprising:
 solidifying and optionally reducing the first less volatile fraction to granules through cooling by contact with the cooled conveyor belt.   
     
     
         17 . The process according to  claim 1 , being a continuous process.