Process to manufacture low sulfur fuels

Abstract

The instant invention relates to a process for producing high octane, low sulfur naphtha products through skeletal isomerization of feed olefins and hydrotreating.

1 . A process for producing low sulfur naphtha products from an olefin and sulfur containing naphtha boiling range feedstream comprising: 
 a) contacting a naphtha boiling range feedstream containing organically bound sulfur and olefins in a first reaction zone operated under effective isomerization conditions and in the presence of hydrogen-containing treat gas with a first catalyst selected from medium pore zeolites to produce a first reaction zone effluent; and    b) hydrotreating at least a portion of the first reaction zone effluent of step a) above in a second reaction zone operated under effective hydrotreating conditions and in the presence of hydrogen-containing treat gas and a second catalyst selected from hydrotreating catalysts comprising about 2 to 20 wt. % of at least one Group VIII metal oxide and about 1 to 50 wt. % of at least one Group VI metal oxide to produce a desulfurized product.    
     
     
         2 . The process according to  claim 1  wherein said first and second reaction zones comprise one or more catalyst beds selected from the group consisting of fluidized beds, ebullating beds, slurry beds, fixed beds, and moving beds wherein each of said one or more catalyst beds contains a catalyst suitable for the reaction zone in which the catalyst bed is located.  
     
     
         3 . The process according to  claim 2  wherein said first and second reaction zones are located in the same reaction vessel.  
     
     
         4 . The process according to  claim 3  wherein said first and second reaction zones comprise one or more fixed catalyst beds.  
     
     
         5 . The process according to  claim 2  wherein said process further comprises interstage cooling between said first and second reaction zone, or between catalyst beds in said first and second reaction zone.  
     
     
         6 . The process according to  claim 2  wherein said first catalyst is selected from ZSM-23 and ZSM-48.  
     
     
         7 . The process according to  claim 2  wherein said first catalyst is ZSM-48.  
     
     
         8 . The process according to  claim 6  wherein said second catalyst is a hydrotreating catalyst comprising about 4 to about 12% of a Group VIII metal oxide and about 10 to about 40 wt. % of a Group VI metal oxide.  
     
     
         9 . The process according to  claim 6  wherein said second catalyst is a hydrotreating catalyst comprising about 1 to 25 wt. % MoO 3 , about 0.1 to 6 wt. % CoO wherein said CoO and MoO 3  are present in an atomic ratio of about 0.1 to about 1.0 Co/Mo, and said catalyst has a median pore diameter of about 75 Å to about 175 Å, wherein said second catalyst has a MoO 3  surface concentration of about 0.5×10 −4  to about 3×10 −4  g and an average particle size diameter of less than 2.0 mm.  
     
     
         10 . The process according to  claim 1  wherein said effective isomerization conditions are selected to cause skeletal isomerization of at least about 20 wt. % of the n-olefins present in said naphtha boiling range feedstream.  
     
     
         11 . The process according to  claim 10  wherein said first reaction zone effluent has a higher ratio of iso-olefins to n-olefins than the naphtha boiling range feedstream.  
     
     
         12 . The process according to  claim 9  wherein said second catalyst further comprises a suitable binder or matrix material selected from zeolites, alumina, silica, titania, calcium oxide, strontium oxide, barium oxide, carbons, zirconia, diatomaceous earth, lanthanide oxides including cerium oxide, lanthanum oxide, neodymium oxide, yttrium oxide, and praseodymium oxide; chromia, thorium oxide, urania, niobia, tantala, tin oxide, zinc oxide, and aluminum phosphate.  
     
     
         13 . The process according to  claim 12  wherein said suitable binder or matrix support of said second catalyst also contains less than about 1 wt. % of contaminants, such as Fe, sulfates, silica, and various metal oxides that can be introduced during the preparation of the support.  
     
     
         14 . The process according to  claim 13  wherein said suitable binder or matrix support of said second catalyst also contains about 0 to 5 wt. % of an additive selected from the group consisting of phosphorus and metals or metal oxides from Group IA (alkali metals) of the Periodic Table of the Elements.  
     
     
         15 . The process according to  claim 12  wherein said suitable binder or matrix material is selected from alumina, silica, and silica-alumina.  
     
     
         16 . The process according to  claim 12  wherein said suitable binder or matrix material is alumina.  
     
     
         17 . The process according to  claim 10  wherein said first catalyst further comprises a suitable porous binder or matrix material selected from clays, silica, and/or metal oxides such as alumina.  
     
     
         18 . The process according to  claim 17  wherein said suitable porous binder or matrix material is selected from silica, alumina, or a kaolin clay.  
     
     
         19 . The process according to  claim 16  wherein said suitable porous binder or matrix material is alumina present in a ratio of less than about 15 parts zeolite to one part binder.  
     
     
         20 . The process according to  claim 19  wherein said effective hydrotreating conditions are selected in such a manner that said desulfurized naphtha product has a sulfur level less than 100 wppm sulfur.  
     
     
         21 . The process according to  claim 20  wherein said effective hydrotreating conditions are selective hydrotreating conditions.  
     
     
         22 . The process according to  claim 20  wherein said desulfurized naphtha product has a higher concentration of iso-paraffins than n-paraffins.  
     
     
         23 . The process according to  claim 22  wherein the naphtha boiling range feedstream containing organically bound sulfur and olefins is preheated prior to entering said first reaction zone.  
     
     
         24 . A process for producing low sulfur naphtha products from an olefin and sulfur containing naphtha boiling range feedstream comprising: 
 a) contacting a naphtha boiling range feedstream containing organically bound sulfur and olefins in a first reaction zone operated under effective isomerization conditions and in the presence of hydrogen-containing treat gas with a first catalyst selected from ZSM-23 and ZSM-48 to produce a first reaction zone effluent having a higher ratio of iso-olefins to n-olefins than the naphtha boiling range feedstream; and    b) hydrotreating at least a portion of the first reaction zone effluent of step a) above in a second reaction zone operated under effective hydrotreating conditions and in the presence of hydrogen-containing treat gas and a second catalyst selected from hydrotreating catalysts comprising about 1 to 25 wt. % MoO 3  about 0.1 to 6 wt. % CoO wherein said CoO and MoO 3  are present in an atomic ratio of about 0.1 to about 1.0 Co/Mo, and said catalyst has a median pore diameter of about 75 Å to about 175 Å, wherein said second catalyst has a MoO 3  surface concentration of about 0.75×10 −4  to about 2.5×10 −4  g and an average particle size diameter of less than 2.0 mm to produce a desulfurized product having a sulfur level less than 100 wppm sulfur and a higher concentration of iso-paraffins than n-paraffins.    
     
     
         25 . The process according to  claim 24  wherein said first catalyst is ZSM-48.  
     
     
         26 . The process according to  claim 25  wherein said second catalyst is a hydrotreating catalyst comprising about 4 to 19 wt. % MoO 3 , about 0.5 to 5.5 wt. % CoO wherein said CoO and MoO 3  are present in an atomic ratio of about 0.20 to about 0.80 Co/Mo, and said catalyst has a median pore diameter of about 75 Å to about 175 Å, wherein said second catalyst has a MoO 3  surface concentration of about 0.5×10 4  to about 3×10 4  g and an average particle size diameter of less than 1.6 mm.  
     
     
         27 . The process according to  claim 26  wherein said effective isomerization conditions are selected to cause skeletal isomerization of at least about 20 wt. % of the n-olefins present in said naphtha boiling range feedstream.  
     
     
         28 . The process according to  claim 26  wherein said second catalyst further comprises a suitable binder or matrix material selected from zeolites, alumina, silica, titania, calcium oxide, strontium oxide, barium oxide, carbons, zirconia, diatomaceous earth, lanthanide oxides including cerium oxide, lanthanum oxide, neodymium oxide, yttrium oxide, and praseodymium oxide; chromia, thorium oxide, urania, niobia, tantala, tin oxide, zinc oxide, and aluminum phosphate.  
     
     
         29 . The process according to  claim 28  wherein said suitable binder or matrix material is selected from alumina, silica, and silica-alumina.  
     
     
         30 . The process according to  claim 24  wherein said first catalyst further comprises a suitable porous binder or matrix material selected from clays, silica, and/or metal oxides such as alumina.  
     
     
         31 . The process according to  claim 30  wherein said first reaction zone catalyst further comprises suitable porous binder or matrix material selected from silica, alumina, or a kaolin clay.  
     
     
         32 . The process according to  claim 31  wherein said effective hydrotreating conditions are selected in such a manner that said desulfurized naphtha product has a sulfur level less than 100 wppm sulfur.  
     
     
         33 . The process according to  claim 32  wherein said second effective hydrotreating conditions are selective hydrotreating conditions.  
     
     
         34 . A process for producing low sulfur naphtha products from an olefin and sulfur containing naphtha boiling range feedstream comprising: 
 a) contacting a naphtha boiling range feedstream containing organically bound sulfur and olefins in a first reaction zone operated under effective isomerization conditions selected to cause skeletal isomerization of at least about 20 wt. % of the n-olefins contained in said feedstream, and in the presence of hydrogen-containing treat gas, with a first catalyst comprising ZSM-48 and an alumina binder, wherein said binder and ZSM-48 are present in a ratio of less than about 15 parts zeolite to one part binder, to produce a first reaction zone effluent having a higher ratio of iso-olefins to n-olefins than the naphtha boiling range feedstream; and    b) hydrotreating the first reaction zone effluent of step a) above in a second reaction zone operated under selective hydrotreating conditions and in the presence of hydrogen-containing treat gas and a second catalyst selected from hydrotreating catalysts comprising about 5 to 16 wt. % MoO 3 , about 1 to 5 wt. % CoO wherein said CoO and MoO 3  are present in an atomic ratio of about 0.25 to about 0.72 Co/Mo, and said catalyst has a median pore diameter of about 80 Å to about 150 Å, wherein said second catalyst has a MoO 3  surface concentration of about 1×10 −4  to 2×10 −4  g and an average particle size diameter of less than 1.4 mm to produce a desulfurized product having a sulfur level less than 50 wppm sulfur and a higher concentration of iso-paraffins than n-paraffins.