Flexible process for enhancing steam cracker and platforming feedstocks

Abstract

A process for increasing the yields of light olefins or shifting to increase the hydrocarbon components to gasoline blending pools from a hydrocarbon feedstock is presented. The process includes separating a naphtha feedstock to components to a first stream that are more readily processed in a cracking unit and to components in a second stream that are more readily processed in a reforming unit. The process includes the ability to convert components from the cracking stream to the reforming stream, and to convert components from the reforming stream to the cracking stream.

1 . A process to increase light olefin and reformate yields, comprising:
 passing a first portion of a hydrocarbon feedstream to a fractionation column to generate an overhead stream comprising C6 compounds and lighter components, and a bottoms stream comprising heavier hydrocarbons;   passing the overhead stream to a cracking unit.   passing the bottoms stream to a separation unit to generate an extract stream comprising normal hydrocarbons, and a raffinate stream comprising non-normal hydrocarbons; and   passing the extract stream to the cracking unit to generate light olefins.   
     
     
         2 . The process of  claim 1  wherein the hydrocarbon feedstream is a naphtha. 
     
     
         3 . The process of  claim 1  further comprising:
 passing the bottoms stream to a hydrotreating unit to generate a treated bottoms stream; and 
 passing the treated bottoms stream to the separation unit. 
 
     
     
         4 . The process of  claim 1  wherein the separation unit is an adsorption separation unit. 
     
     
         5 . The process of  claim 1  further comprising passing the raffinate stream to a reforming unit to generate a reformate stream comprising aromatics. 
     
     
         6 . The process of  claim 1  further comprising passing a second portion of the hydrocarbon feedstream to the cracking unit. 
     
     
         7 . The process of  claim 1  wherein the cracking unit is a naphtha steam cracking unit. 
     
     
         8 . A process for increasing light olefin yields comprising:
 passing a hydrocarbon stream to a fractionation column to generate a first overhead stream comprising nC4 and lighter hydrocarbons, and a first bottoms stream comprising C5 and heavier hydrocarbons;   passing the first bottoms stream to a hydrotreating unit to generate a treated bottoms stream;   passing the treated bottoms stream to a separation unit to generate an extract stream comprising normal hydrocarbons, and a raffinate stream comprising non-normal hydrocarbons;   passing the raffinate stream to a reforming unit to generate a reformate stream; and   passing the extract stream to a cracking unit to generate light olefins.   
     
     
         9 . The process of  claim 8  wherein the hydrotreating unit generates a treated first bottoms stream having a reduced acetylenes, diolefins, sulfur and nitrogen content. 
     
     
         10 . The process of  claim 9  wherein the hydrotreating unit is a naphtha hydrotreating unit. 
     
     
         11 . The process of  claim 8  wherein the hydrocarbon stream comprises a naphtha. 
     
     
         12 . The process of  claim 8  further comprising passing raffinate stream to a raffinate separation system to generate a second overhead stream comprising C5 and C6 hydrocarbons, an intermediate stream comprising C7 and heavier alkanes, C6 and heavier aromatics and naphthenes, and a second bottoms stream comprising desorbent. 
     
     
         13 . The process of  claim 12  further comprising passing the intermediate stream to the reforming unit. 
     
     
         14 . The process of  claim 12  further comprising passing the second overhead stream to an isomerization unit to generate an isomerization process stream comprising isoparaffins and normal paraffins. 
     
     
         15 . The process of  claim 14  further comprising passing the isomerization process stream to the separation unit. 
     
     
         16 . A process for providing flexibility in gasoline production:
 passing a hydrocarbon stream to a fractionation column to generate a first overhead stream comprising nC4 and lighter hydrocarbons, and a first bottoms stream comprising C5 and heavier hydrocarbons;   passing the first bottoms stream to a hydrogenation unit to generate a treated bottoms stream having a reduced acetylene and diolefins content;   passing the treated bottoms stream to a separation unit to generate an extract stream comprising normal hydrocarbons, and a raffinate stream comprising non-normal hydrocarbons;   passing the raffinate stream to a reforming unit to generate a reformate stream; and   passing a portion of the extract stream to a cracking unit to generate light olefins.   
     
     
         17 . The process of  claim 16  further comprising passing the extract stream to an extract separation system to generate a second overhead stream comprising C5 and C6 normal alkanes, an intermediate stream comprising C7 and heavier normal alkanes, and a second bottoms stream comprising desorbent. 
     
     
         18 . The process of  claim 17  further comprising passing the second overhead stream to an isomerization unit to generate an isomerization process stream. 
     
     
         19 . The process of  claim 18  further comprising passing the isomerization process stream to the separation unit. 
     
     
         20 . The process of  claim 17  further comprising passing the intermediate stream to the cracking unit.