Process and apparatus for treating mercaptans in a naphtha boiling range feed

Abstract

Processes and apparatuses are disclosed for treating a naphtha boiling range stream containing mercaptan compounds. The process includes oxidizing mercaptan compounds in the naphtha boiling range stream to provide a mercaptan-depleted naphtha stream rich in disulfide compounds; passing the mercaptan-depleted naphtha stream rich in disulfide compounds to a naphtha splitter column; and fractionating at least a portion of the mercaptan-depleted naphtha stream rich in disulfide compounds into at least two streams, a light naphtha stream lean in disulfide compounds and a heavy naphtha stream rich in disulfide compounds. The heavy naphtha stream rich in disulfide compounds may be passed to a hydroprocessing unit to convert organic disulfides in the stream to hydrocarbons and hydrogen sulfide. A heavy naphtha stream lean in disulfide compounds can be recovered and routed as desired by the refiner.

1 . A process for treating a naphtha boiling range stream containing mercaptan compounds, the process comprising:
 (a) oxidizing mercaptan compounds in the naphtha boiling range stream to provide a mercaptan-depleted naphtha stream rich in disulfide compounds;   (b) passing the mercaptan-depleted naphtha stream rich in disulfide compounds to a naphtha splitter column; and   (c) fractionating at least a portion of the mercaptan-depleted naphtha stream rich in disulfide compounds into at least two streams, a light naphtha stream lean in disulfide compounds and a heavy naphtha stream rich in disulfide compounds.   
     
     
         2 . The process of  claim 1 , wherein the naphtha boiling range stream comprises straight-run naphtha. 
     
     
         3 . The process of  claim 1 , wherein oxidizing mercaptan compounds comprises contacting the mercaptan compounds in the naphtha boiling range stream with an oxidizing catalyst and oxygen. 
     
     
         4 . The process of  claim 3 , wherein the oxidizing catalyst comprises a metal component retained on an inorganic oxide support, wherein the metal component is selected from one or more of vanadium, chromium, manganese, cobalt, nickel, copper, and zinc. 
     
     
         5 . The process of  claim 4 , wherein the metal component comprises copper. 
     
     
         6 . The process of  claim 5 , wherein the copper is present as copper metal, copper oxide, copper sulfide, or a combination thereof. 
     
     
         7 . The process of  claim 4 , wherein the metal component is present in an amount of from 10 to 40 wt. %, based on a total weight of the catalyst. 
     
     
         8 . The process of  claim 4 , wherein the inorganic oxide support is selected from alumina, silica, zirconia, titania, thoria, boria, magnesia, chromia, stannic oxide, and combinations thereof. 
     
     
         9 . The process  claim 1 , wherein conditions for oxidizing mercaptan compounds include a pressure of from 101 to 2068 kPa; a temperature of from 35° C. to 200° C.; and a liquid hourly space velocity of from 1 to 10 h −1  (e.g., 1 to 5 h −1 ). 
     
     
         10 . The process of  claim 1 , wherein mercaptan compounds in the naphtha boiling range stream are depleted in the substantial absence of any caustic solvent. 
     
     
         11 . The process of  claim 1 , wherein the straight-run naphtha is derived from crude oil or natural gas condensate resources. 
     
     
         12 . An apparatus for treating a naphtha boiling range stream containing mercaptan compounds, the apparatus comprising:
 (a) an oxidation unit to provide a mercaptan-depleted naphtha stream rich in disulfide compounds; and   (b) a naphtha splitter column in downstream communication with the oxidation unit to provide a light naphtha stream lean in disulfide compounds in a naphtha splitter overhead line and a heavy naphtha stream rich in disulfide compounds in a naphtha splitter bottoms line.   
     
     
         13 . The apparatus of  claim 12 , further comprising a hydroprocessing unit in downstream communication with the naphtha splitter bottoms line to provide a heavy naphtha stream lean in disulfide compounds. 
     
     
         14 . The apparatus of  claim 12 , further comprising a distillation unit in upstream communication with the oxidation unit to provide a naphtha boiling range stream. 
     
     
         15 . The apparatus of  claim 14 , wherein the distillation unit is a crude oil atmospheric distillation unit or a natural gas condensate splitter column.