Multi-stage countercurrent hydrotreating process

Abstract

A multi-stage process for removing heteroatoms particularly organic sulfur and nitrogen components, from liquid petroleum and chemical streams. The feedstream flows countercurrent to the flow of a hydrogen-containing treat gas and is reacted with a first catalyst which is relatively tolerant to sulfur and nitrogen, such as a CoMo supported catalyst. When the level of organic sulfur in the feedstream is less than about 3,000 wppm and the level of organic nitrogen is less than about 1,000 wppm, the feedstream is reacted with said counter flowing hydrogen-containing treat gas in the presence of a catalyst comprised of Ni and a Group VIA metal selected from Mo, W, or both, on a refractory support. The reaction vessel preferably contains vapor and optionally liquid by-pass means in one or more of the catalyst beds.

What is claimed is:  
     
         1 . A multi-stage process for removing sulfur and nitrogen components from distillate boiling range petroleum feedstreams containing at least one of said components, in the presence of a hydrogen-containing treat gas, the process which comprises: 
 reacting said feedstock in a first reaction stage with said hydrogen-containing treat gas in the presence of a bed catalyst comprised of Co and Mo on a refractory support until the reacted feedstock contains less than about 3,000 wppm sulfur and less than about 1,000 wppm nitrogen; and    reacting said reacted feedstock from said first reaction stage in a second stage with counterflowing hydrogen-containing treat gas in the presence of a bed of catalyst comprised of Ni and one or both of a metal selected from Mo and W, on a refractory support.    
     
     
         2 . The process of  claim 1  wherein the process conditions for the first reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         3 . The process of  claim 1  wherein the process conditions for the second reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         4 . The process of  claim 2  wherein the process conditions for the second reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         5 . The process of  claim 1  wherein the first reaction stage is also operated in countercurrent mode wherein the feedstream and treat gas flow countercurrent to each other.  
     
     
         6 . The process of  claim 1  wherein the amount of Co in the first reaction stage catalyst is from about 2 wt. % to 20 wt. %, based on the total weight of the catalyst.  
     
     
         7 . The process of  claim 1  wherein the amount of Mo in the first stage catalyst is from about 5 to about 50 wt. %, based on the total weight of the catalyst.  
     
     
         8 . The process of  claim 6  wherein the amount of Mo in the first stage catalyst is from about 5 to about 50 wt. %, based on the total weight of the catalyst.  
     
     
         9 . The process of  claim 1  wherein the catalyst of the second reaction stage is comprised of Ni, Mo, and W.  
     
     
         10 . The process of  claim 1  wherein there is provided at least one additional reaction stage following said second reaction stage, which at least one additional reaction stage is selected from the group consisting of an aromatics hydrogenation stage and a hydrocracking stage.  
     
     
         11 . The process of  claim 1  wherein one or more of said reaction stages contains at least one vapor passageway extending through or around at least a portion of the catalyst bed of the stage containing said passageway so that a portion of upflowng hydrogen-containing treat gas bypasses a vertical portion of said catalyst bed.  
     
     
         12 . A multi-stage process for removing sulfur and nitrogen components from distillate boiling range petroleum feedstreams containing at least one of said components, in the presence of a hydrogen-containing treat gas flowing countercurrent to the flow of said feedstream in at least one of the reaction stages, the process which comprises: 
 reacting said feedstock in a first reaction stage with said hydrogen-containing treat gas in the presence of a catalyst comprised of Co and Mo on a refractory support until the reacted feedstock contains less than about 1,500 wppm sulfur and less than about 750 wppm nitrogen; and    reacting said treated feedstock from said first reaction stage in a second stage with counterflowing hydrogen-containing treat gas in the presence of a catalyst comprised of Ni, Mo and W, on a refractory support.    
     
     
         13 . The process of  claim 12  wherein the process conditions for the first reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         14 . The process of  claim 12  wherein the process conditions for the second reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         15 . The process of  claim 13  wherein the process conditions for the second reaction stage include temperatures ranging from about 100° C. to about 400° C. and pressures from about 50 psig to about 2,000 psig.  
     
     
         16 . The process of  claim 12  wherein the first reaction stage is also operated in countercurrent mode wherein the feedstream and treat gas flow countercurrent to each other.  
     
     
         17 . The process of  claim 12  wherein the amount of Co in the first reaction stage catalyst is from about 2 wt. % to 20 wt. %, based on the total weight of the catalyst.  
     
     
         18 . The process of  claim 12  wherein the amount of Mo in the first stage catalyst is from about 5 to about 50 wt. %, based on the total weight of the catalyst.  
     
     
         19 . The process of  claim 17  wherein the amount of Mo in the first stage catalyst is from about 5 to about 50 wt. %, based on the total weight of the catalyst.  
     
     
         20 . The process of  claim 12  wherein there is provided at least one additional reaction stage following said second reaction stage, which at least one additional reaction stages is selected from the group consisting of an aromatics hydrogenation stage and a hydrocracking stage.  
     
     
         22 . The process of  claim 12  wherein one or more of said reaction stages contains at least one vapor passageway extending through or around at least a portion of the catalyst bed of the stage containing said passageway so that a portion of upflowng hydrogen-containing treat gas bypasses a vertical portion of said catalyst bed.