Flow control to meet e70 gasoline specifications

Abstract

A process is presented for recovering the components for a gasoline blending pool to meet the E70 specifications. The process includes the separation of the naphtha feedstock into a light naphtha stream and a heavy naphtha stream. The process further includes separating the light naphtha stream to recovery high quality non-normal hydrocarbons having normal boiling points above 70° C., and to separate for adding to the feed to the reforming unit, hydrocarbons that have lower boiling points.

1 . A process for improving stream cracker feed and processing gasoline blending components, comprising:
 passing a naphtha feedstream to a fractionation column to generate an overhead stream comprising hydrocarbons with normal boiling points below 90° C., and a bottoms stream comprising heavies;   passing the overhead stream to a separation unit to generate an extract stream comprising normal hydrocarbons and a raffinate stream comprising non-normal hydrocarbons;   passing the extract stream to a cracking unit; and   passing the bottoms stream to a reforming unit.   
     
     
         2 . The process of  claim 1  wherein the fractionation column is operated to generate an overhead stream comprising hydrocarbons having normal boiling points below 72° C. 
     
     
         3 . The process of  claim 1  wherein the fractionation column is operated to generate an overhead stream comprising hydrocarbons having normal boiling points below 81° C. 
     
     
         4 . The process of  claim 1  wherein the fractionation column is operated to generate an overhead stream comprising hydrocarbons having normal boiling points below 98° C. 
     
     
         5 . The process of  claim 1  wherein the separation unit is an adsorption separation unit. 
     
     
         6 . The process of  claim 1  wherein the light desorbent is a normal paraffin with a boiling point lower than the lightest feed component, or higher than the boiling point of the heavies components. 
     
     
         7 . The process of  claim 1  further comprising passing the raffinate stream to the reforming unit. 
     
     
         8 . The process of  claim 1  further comprising passing the raffinate stream to a second fractionation column to generate a second overhead stream and a second bottoms stream. 
     
     
         9 . The process of  claim 8  wherein the overhead stream comprises isobutane and isopentane. 
     
     
         10 . The process of  claim 8  wherein the fractionation column has a side draw, and further comprising generating a side draw stream comprising high octane light naphtha product, wherein the high octane light naphtha product comprises isopentane, cyclopentane, methylcyclopentane and isohexane. 
     
     
         11 . The process of  claim 10  further comprising passing the high octane light naphtha product to a gasoline blending stock. 
     
     
         12 . The process of  claim 8  wherein the fractionation column has a side draw, and further comprising generating a side draw stream comprising high octane light naphtha product, wherein the high octane light naphtha product comprises isopentane, cyclopentane, methylcyclopentane, isohexanes, cyclohexane, benzene, and dimethylpentanes. 
     
     
         13 . The process of  claim 12  further comprising passing the high octane light naphtha product to a gasoline blending stock. 
     
     
         14 . The process of  claim 8  further comprising passing the second bottoms stream to the reforming unit. 
     
     
         15 . The process of  claim 8  further comprising passing the second overhead stream to the reforming unit. 
     
     
         16 . The process of  claim 1  wherein the reforming unit generates a reformate stream, and further comprising passing the reformate stream to an aromatics recovery unit to generate an aromatics stream and an aromatics raffinate stream comprising normal alkanes. 
     
     
         17 . The process of  claim 16  further comprising passing the aromatics raffinate stream to the cracking unit. 
     
     
         18 . The process of  claim 1  wherein the feed to the catalytic reforming unit has a feed that is depleted in normal hexane and rich in iso-hexane isomers such that the ratio of iso-hexanes to normal hexane is greater than 3. 
     
     
         19 . The process of  claim 1  wherein the feed to the catalytic reforming unit has a feed that is depleted in normal pentane and rich in iso-pentane such that the ratio of iso-pentane to normal pentane is greater than 3. 
     
     
         20 . The process of  claim 1  wherein the feed to the catalytic reforming unit has a feed that is depleted in normal butane and rich in iso-butane such that the ratio of iso-butane to normal butane is greater than 3. 
     
     
         21 . A process for improving naphtha stream cracker feedstock and processing gasoline blending components, comprising:
 passing a naphtha feedstream to a fractionation column to generate an overhead stream comprising hydrocarbons with normal boiling points below 75° C., and a bottoms stream;   passing the overhead stream to an adsorption separation unit to generate an extract stream comprising normal hydrocarbons and a raffinate stream comprising non-normal hydrocarbons;   passing the raffinate stream to a second fractionation column to generate an overhead stream, a side stream and a second bottoms stream;   passing the extract stream to a cracking unit; and   passing the bottoms stream to a reforming unit to generate a reformate.   
     
     
         22 . The process of  claim 21  further comprising operating the second fractionation column with a second bottom product cut point of 70° C. (at atmospheric pressure) and sending the second bottoms product to the reforming unit. 
     
     
         23 . The process of  claim 21  further comprising operating the second fractionation column with a second top product cut point of about 30° C. (at atmospheric pressure) and sending the second overhead product to the reforming unit. 
     
     
         24 . The process of  claim 21  further comprising using the side product from the second fractionation column for gasoline blending. 
     
     
         25 . The process of  claim 21  wherein the adsorption separation column uses a light desorbent. 
     
     
         26 . The process of  claim 25  wherein the light desorbent is n-butane. 
     
     
         27 . The process of  claim 21  further comprising passing the reformate to an aromatics recovery unit to generate an aromatics stream, and an aromatics raffinate stream comprising non-aromatic compounds. 
     
     
         28 . The process of  claim 27  further comprising passing the aromatics raffinate stream to the adsorption separation unit.