High Purity Heavy Normal Paraffins Utilizing Integrated Systems

Abstract

A process is presented for producing a purified normal paraffin product stream. The process includes passing a hydrocarbon stream having the desired normal paraffins to an adsorption separation system. A process stream generated from the separation system and having the normal paraffins is passed to an adsorption unit for the selective adsorption of aromatic compounds from the process stream, thereby producing a purified product.

1 . A process for producing a purified heavy normal paraffin, comprising:
 passing a hydrocarbon feedstream to a prefractionation unit, thereby generating a first stream comprising light ends, a second stream comprising heavy ends, and a third stream comprising the selected hydrocarbons;   passing the third stream to a hydroprocessing unit, thereby creating a effluent stream having reduced contaminants;   passing the effluent stream to an adsorption separation unit, thereby creating an extract stream comprising normal paraffins, and a raffinate stream comprising non-normal hydrocarbons and desorbent; and   passing the extract stream to an aromatics adsorbent unit for selective adsorption of aromatics, thereby creating a process extract stream having heavy aromatic content of less than 0.5 wt %.   
     
     
         2 . The process of  claim 1  wherein the heavy aromatic content comprises aromatics in the C14 to C17 range. 
     
     
         3 . The process of  claim 1  further comprising the process extract stream to a separation unit, thereby creating the purified heavy normal paraffin stream, and a light aromatics stream. 
     
     
         4 . The process of  claim 3  wherein the light aromatics stream comprises C6 to C8 aromatics. 
     
     
         5 . The process of  claim 4  wherein the light aromatics stream comprises para-xylene. 
     
     
         6 . The process of  claim 1  further comprising regeneration of the aromatics adsorbent unit. 
     
     
         7 . The process of  claim 6  wherein the regeneration comprises:
 purging the adsorbent unit, thereby creating a purge stream; and 
 passing a desorbent through the adsorbent unit, thereby creating a desorption stream. 
 
     
     
         8 . The process of  claim 7  wherein the adsorbent unit is purged with a purge stream comprising light hydrocarbons in the C5 to C10 range. 
     
     
         9 . The process of  claim 8  wherein the purge stream comprises mixture of pentane and isooctane. 
     
     
         10 . The process of  claim 7  wherein the adsorbent unit is treated with paraxylene desorbent. 
     
     
         11 . The process of  claim 7  wherein the purge stream and the desorption stream are passed to a separation unit, thereby creating a first stream comprising the purge stream, a second stream comprising the desorbent, and a third stream comprising aromatics in the C14 to C17 range. 
     
     
         12 . The process of  claim 1  wherein the hydroprocessing unit also performs partial hydrogenation of aromatics. 
     
     
         13 . The process of  claim 1  wherein the heavy aromatic content in the process extract stream is less than 100 ppmw. 
     
     
         14 . The process of  claim 1  wherein the selected hydrocarbons are C14 to C17 hydrocarbons. 
     
     
         15 . A process for producing a purified heavy normal paraffin, comprising:
 passing a hydrocarbon feedstream to a prefractionation unit, thereby generating a first stream comprising light ends comprising hydrocarbons having 13 or less carbon atoms, a second stream comprising heavy ends comprising hydrocarbons having 18 or more carbon atoms, and a third stream comprising the selected hydrocarbons having from 14 to 17 carbon atoms;   passing the third stream to a hydroprocessing unit, thereby creating a effluent stream having reduced contaminants, and partially hydrogenating aromatics;   passing the effluent stream to an adsorption separation unit, thereby creating an extract stream comprising normal paraffins, and a raffinate stream comprising non-normal hydrocarbons;   passing the extract stream to an on-line aromatics adsorbent unit for selective adsorption of aromatics in the C14 to C17 range, thereby creating a process extract stream having an aromatic content in the C14 to C17 range of less than 0.5 wt %; and   passing the extract stream to an extract separation unit, thereby creating a purified heavy normal paraffin stream, and an overhead stream.   
     
     
         16 . The process of  claim 15  wherein the overhead stream from the extract separation unit comprises a desorption hydrocarbon used to remove adsorbed aromatics from the adsorption unit. 
     
     
         17 . The process of  claim 16  wherein the desorption hydrocarbon comprises para-xylene. 
     
     
         18 . The process of  claim 15  wherein the regeneration comprises:
 taking the aromatics adsorbent unit off-line; 
 purging the off-line adsorbent unit, thereby creating a purge stream; and 
 passing a desorbent through the adsorbent unit, thereby creating a desorption stream. 
 
     
     
         19 . The process of  claim 18  wherein the purge stream and the desorption stream are passed to a separation unit, thereby creating a first stream comprising the purge material, a second stream comprising the desorbent, and a third stream comprising aromatics in the C14 to C17 range. 
     
     
         20 . The process of  claim 15  wherein the process utilizes at least two aromatics adsorbent units, and at least one adsorbent unit is off-line, further comprising:
 taking the on-line aromatics adsorbent unit off-line for regeneration; and 
 putting the off-line aromatics adsorbent unit on-line.