Treatment of Heavy Oils to Reduce Olefin Content

Abstract

A process for treating heavy oil to provide a treated heavy oil having a reduced density and viscosity, as well as an olefin content that does not exceed 1.0 wt. %. The process comprises separating the initial heavy oil into a first fraction, which in general contains lower-boiling components, and a second fraction. The second fraction comprises a heavy oil having a p-value of at least 5% greater than the p-value of the initial heavy oil prior to separating the initial heavy oil into the first fraction and the second fraction, and the second fraction has an aromaticity that is no more than 5% less than the aromaticity of the initial heavy oil prior to separating the initial heavy oil into the first fraction and the second fraction. The second fraction then is upgraded to reduce the density and viscosity of the heavy oil. After the second fraction is upgraded, it is recombined with at least a portion of the first fraction to provide a treated heavy oil having an olefin content that does not exceed 1.0 wt. %. The separation of the initial heavy oil into first and second fractions enables one to achieve improved reduction of the density and viscosity of the treated heavy oil while maintaining the olefin content at an acceptable level.

What is claimed is: 
     
         1 . A process for treating a heavy oil to provide a treated heavy oil having a reduced density and viscosity, and an olefin content that does not exceed 1.0 wt. %, comprising:
 (a) separating an initial heavy oil into a first fraction and a second fraction, wherein said second fraction comprises a heavy oil having a p-value of at least 5% greater than the p-value of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction, and said second fraction has an aromaticity that is no more than 5% less than the aromaticity of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction;   (b) reducing the density and viscosity of said second fraction; and   (c) combining said second fraction with at least a portion of said first fraction to provide a treated heavy oil having an olefin content that does not exceed 1.0 wt. %.   
     
     
         2 . The process of  claim 1  wherein said first fraction has a boiling range that does not exceed 450° C. 
     
     
         3 . The process of  claim 2  wherein said first fraction has a boiling range that does not exceed 325° C. 
     
     
         4 . The process of  claim 3  wherein said first fraction has a boiling range that does not exceed 250° C. 
     
     
         5 . The process of  claim 4  wherein said first fraction has a boiling range that does not exceed 180° C. 
     
     
         6 . The process of  claim 5  wherein said first fraction has a boiling range that does not exceed 150° C. 
     
     
         7 . The process of  claim 1  wherein said second fraction has a p-value which is at least 10% greater than the p-value of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction. 
     
     
         8 . The process of  claim 7  wherein said second fraction has a p-value which is at least 15% greater than the p-value of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction. 
     
     
         9 . The process of  claim 8  wherein said second fraction has a p-value which is at least 25% greater than the p-value of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction. 
     
     
         10 . The process of  claim 1  wherein said second fraction has an aromaticity that is no more than 3% less of the aromaticity of said initial heavy oil prior to separating said initial heavy oil into said first fraction and said second fraction. 
     
     
         11 . The process of  claim 10  wherein said second fraction has an aromaticity that is at least 3% greater than the aromaticity of said initial heavy oil prior to separation of initial said heavy oil into said first fraction and said second fraction. 
     
     
         12 . The process of  claim 11  wherein said second fraction has an aromaticity that is at least 5% greater than the aromaticity of said initial heavy oil prior to separation of said initial heavy oil into said first fraction and said second fraction. 
     
     
         13 . The method of  claim 1  wherein the density and viscosity of said second fraction are reduced by heating said second fraction to a temperature of from about 200° C. to about 600° C. 
     
     
         14 . The method of  claim 13  wherein the density and viscosity of said second fraction are reduced by heating said second fraction to a temperature of from about 350° C. to about 450° C. 
     
     
         15 . The method of  claim 14  wherein the density and viscosity of said second fraction are reduced by heating said second fraction to a temperature of from about 380° C. to about 420° C. 
     
     
         16 . The method of  claim 13  where said second fraction is heated for a period of time of from about 1 minute to about 20 minutes. 
     
     
         17 . The method of  claim 16  wherein said second fraction is heated for a period of time of from about 3 minutes to about 8 minutes. 
     
     
         18 . The method of  claim 1  wherein the density and viscosity of said second fraction are reduced by subjecting said second fraction to cavitation. 
     
     
         19 . The method of  claim 18  wherein said second fraction is subjected to hydrodynamic cavitation. 
     
     
         20 . The method of  claim 19  wherein said second fraction is subjected to hydrodynamic cavitation by passing said second fraction from a conduit through a cavitation zone, wherein the ratio of the width of said cavitation zone to the width of said conduit is from about 1/230 to 1/75. 
     
     
         21 . The method of  claim 20  wherein the ratio of the length of the cavitation zone to the width of the cavitation zone is from about 10 to about 125. 
     
     
         22 . The method of  claim 21  wherein the ratio of the length of the cavitation zone to the width of the cavitation zone is from about 50 to about 125. 
     
     
         23 . The method of  claim 1  wherein the density and viscosity of said second fraction are reduced by heating said second fraction to a temperature of from about 200° C. to about 600° C., and then subjecting said second fraction to cavitation. 
     
     
         24 . The method of  claim 23  wherein said second fraction is heated to a temperature of from about 350° C. to about 450° C. 
     
     
         25 . The method of  claim 24  wherein said second fraction is heated to a temperature of from about 380° C. to about 420° C. 
     
     
         26 . The method of  claim 23  wherein said second fraction is subjected to hydrodynamic cavitation. 
     
     
         27 . The method of  claim 26  wherein said second fraction is subjected to hydrodynamic cavitation by passing said second fraction from a conduit through a cavitation zone, wherein the ratio of the width of said cavitation zone to the width of said conduit is from about 1/230 to 1/75. 
     
     
         28 . The method of  claim 27  wherein the ratio of the length of the cavitation zone to the width of the cavitation zone is from about 10 to about 125. 
     
     
         29 . The method of  claim 28  wherein the ratio of the length of the cavitation zone to the width of the cavitation zone is from about 50 to about 125. 
     
     
         30 . The method of  claim 1  wherein the density and viscosity of said second fraction are reduced by subjecting said second fraction to a hydrogen addition process.