Combined naphtha refining and butane upgrading process

Abstract

A process for refining naphtha and upgrading butanes is described. The process involves separating a hydrotreated heavy naphtha feed into a C 7 -rich fraction and a C 8 +-rich fraction in a separation zone and then reacting the C 7 -rich fraction with C 4 paraffins to form to a low aromatic gasoline blendstock. The C 8+ -rich fraction is sent to a reforming zone to form a reformed product with higher octane and lower RVP than a reformed product derived from heavy naphtha.

what is claimed is: 
     
         1 . A process for refining naphtha and upgrading butanes comprising:
 separating a hydrotreated heavy naphtha feed into a C 7 -rich fraction and a C 8 +-rich fraction in a separation zone;   introducing the C 7 -rich fraction into a reaction zone;   introducing a stream comprising C 4  paraffins into the reaction zone;   disproportionating a first portion of the C 7 -rich fraction by contacting the first portion of the C 7 -rich fraction with a catalyst in the reaction zone and reverse disproportionating a second portion of the C 7 -rich fraction and the C 4  paraffins by contacting the second portion of the C 7 -rich fraction and the C 4  paraffins with the catalyst in the reaction zone under reaction conditions suitable for disproportionation and reverse disproportionation to form a reaction product mixture;   separating the reaction product mixture in a second separation zone into at least a C 3− -rich stream, an iso-C 4  -rich stream, and a C 6+ -rich stream; and   introducing the C 6+ -rich stream into a hydrocarbon pool.   
     
     
         2 . The process of  claim 1  further comprising reforming the C 8+ -rich fraction in a reforming zone to form a higher octane reformed product and introducing the reformed product into the hydrocarbon pool. 
     
     
         3 . The process of  claim 1  wherein separating the reaction product mixture comprises separating the reaction product mixture into at least the C 3− -rich stream, the iso-C 4 -rich stream, a C 5 -rich stream, and the C 6+ -rich stream. 
     
     
         4 . The process of  claim 3  further comprising controlling a vapor pressure of the C 6+ -rich stream by recovering at least a portion of the C 5 -rich stream. 
     
     
         5 . The process of  claim 3  further comprising maximizing a gasoline product yield by mixing at least a portion of the C 5 -rich stream with the C 6+ -rich stream. 
     
     
         6 . The process of  claim 3  further comprising recycling at least a portion of the C 5 -rich stream to the reaction zone. 
     
     
         7 . The process of  claim 1  wherein the reaction conditions include a temperature of less than about 200° C. 
     
     
         8 . The process of  claim 1  further comprising introducing the iso-C 4 -rich stream and at least one olefin containing stream into an alkylation reaction zone to produce low vapor pressure, high octane gasoline blendstock. 
     
     
         9 . The process of  claim 1  wherein a molar ratio of C 4  to C 7  is at least about 0.055. 
     
     
         10 . The process of  claim 1  further comprising recycling at least a portion of the iso-C 4  -rich stream to the reaction zone. 
     
     
         11 . The process of  claim 1  wherein at least one of the first or second catalyst comprises HF, sulfated zirconias, AlCl 2 /SiO 2 , zeolites, ionic solids, platinum on chlorided Al 2 O 3 /Ga 2 O 3  supports, supported ionic liquids, Pt/W/Al 2 O 3 , HF/TiF 4 , an ionic liquid, or combinations thereof. 
     
     
         12 . The process of  claim 1 , wherein the catalyst is a liquid catalyst comprising an ionic liquid and a carbocation promoter. 
     
     
         13 . The process of  claim 12  wherein the ionic liquid comprises an organic cation and an anion, and wherein the organic cation is selected from the group consisting of: 
       
         
           
           
               
               
           
         
       
       where R 1 -R 21  are independently selected from C 1 -C 20  hydrocarbons, C 1 -C 20  hydrocarbon derivatives, halogens, and H. 
     
     
         14 . The process of  claim 12  wherein the ionic liquid comprises an organic cation and an anion, and wherein the anion is derived from halides, sulfates, bisulfates, nitrates, sulfonates, fluoroalkanesulfonates, or combinations thereof. 
     
     
         15 . The process of  claim 12  wherein the carbocation promoter comprises halo-alkanes, mineral acids, alkenes, or combinations thereof. 
     
     
         16 . The process of  claim 12  further comprising mechanically mixing while contacting the C 7 -rich fraction with the catalyst and while contacting the C 7 -rich and the C 4  paraffins with the catalyst. 
     
     
         17 . The process of  claim 1  further comprising:
 separating the catalyst from the reaction product mixture before separating the reaction product mixture; 
 regenerating the separated catalysts; 
 optionally, adding a carbocation promoter to the regenerated catalyst; and 
 recycling at least a portion of the regenerated catalyst to the reaction zone. 
 
     
     
         18 . The process of  claim 1  wherein a mass ratio of the catalyst to the C 7  fraction and the butanes is less than 0.75:1. 
     
     
         19 . The process of  claim 1  wherein the hydrotreated heavy naphtha feed is formed by separating a full range hydrotreated naphtha feed into a hydrotreated light naphtha stream and the hydrotreated heavy naphtha feed. 
     
     
         20 . A process for refining naphtha and upgrading butanes comprising:
 separating a hydrotreated heavy naphtha feed into a C 7 -rich fraction and a C 8 +-rich fraction in a separation zone;   introducing the C 7 -rich fraction into a reaction zone;   introducing a stream comprising C 4  paraffins into the reaction zone;   disproportionating a first portion of the C 7 -rich fraction by contacting the first portion of the C 7 -rich fraction with a liquid catalyst in the reaction zone and reverse disproportionating a second portion of the C 7 -rich fraction and the C 4  paraffins by contacting the second portion of the C 7 -rich fraction and the C 4  paraffins with the liquid catalyst in the reaction zone under reaction conditions suitable for disproportionation and reverse disproportionation to form a reaction product mixture, wherein the liquid catalyst comprises an ionic liquid and a carbocation promoter;   separating the liquid catalyst from the reaction product mixture;   separating the reaction mixture in a second separation zone into at least a C 3− -rich stream, an iso-C 4 -rich stream, and a C 6+ -rich stream;   introducing the C 6+ -rich stream into a hydrocarbon pool; and   reforming the C 8+ -rich fraction in a reforming zone to form a reformed product and introducing the reformed product into the hydrocarbon pool.