Catayst activation method for selective cat naphtha hydrodesulfurization (GJH-0038)

Abstract

An improved catalyst activation process for olefinic naphtha hydrodesulfurization. This process maintains the sulfur removal activity of the catalyst while reducing the olefin saturation activity.

What is claimed is:  
     
         1 . A process for the activation of a CoMo supported catalyst for the selective hydrodesulfurization of naphtha feedstock containing significant amounts of sulfur and olefins, without saturating a significant amount of the olefins, which process comprises: 
 a) heating the catalyst to a temperature of about 350° F. to about 450° F. in an effective amount of time, in the presence of hydrogen and hydrogen sulfide, and in the presence of virgin naphtha at an effective pressure such that the environment is not a reducing environment;    b) holding the catalyst at 350° F. to about 450° F. for an effective amount of time so that at least 20% of the metals that will sulfide will sulfide; and    c) further heating said catalyst to a temperature from about 550° F. to 700° F. in the presence of hydrogen and hydrogen sulfide and in the presence of virgin naphtha and at an effective pressure such that the environment is non-reducing, so that substantially all of the metals are sulfided.    
     
     
         2 . The process of    claim 1    wherein the naphtha feedstock is a cracked naphtha feedstock and contains about 5 wt. % to about 50 wt. % olefins.  
     
     
         3 . The process of    claim 2    wherein the naphtha feedstock has a diene concentration of about 0.02 to 15 wt. %.  
     
     
         4 . The process of    claim 1    wherein the temperature of step a) is reached by heating at a rate of about 10° F. to about 80° F. per hour.  
     
     
         5 . The process of    claim 1    wherein the total pressure if from about 200 to 400 psig.  
     
     
         6 . The process of    claim 1    wherein the temperature of step a) is reached by heating at a rate of about 30 to 60° F. per hour at a total pressure of about 250 to 350 psig.  
     
     
         7 . The process of    claim 2    wherein the naphtha feedstock is a cat naphtha and contains a sulfur concentration of about 0.05 to 0.7 wt. %, based on the total weight of the naphtha.  
     
     
         8 . The process of    claim 7    wherein the naphtha is selected from the group consisting of cat naphtha, coker naphtha, hydrocracker naphtha, resid, and hydrotreater naphtha.  
     
     
         9 . The process of    claim 1    wherein the virgin naphtha used in step (a) contains about 100 wppm to about 1,000 wppm sulfur and substantially no olefins.