Producing low sulfur naphtha products through improved olefin isomerization

A process for producing low sulfur naphtha products comprising;

• a) contacting a naphtha boiling range feedstream containing organically bound sulfur, nitrogen-containing compounds, and olefins in a first reaction zone operated under conditions effective to remove at least a portion of said nitrogen-containing compounds with an acidic material selected from amberlyst and alumina to produce a first reaction zone effluent having less than 50 wppm total nitrogen;
• b) contacting at least a portion of said first reaction zone effluent in a second reaction zone operated under effective hydroisomerization conditions and in the presence of hydrogen-containing treat gas with a second catalyst comprising at least one zeolite selected from ZSM-23 and ZSM-48 and having an alpha value in the range of about 2 to about 80 to produce a second reaction zone effluent;
• and
• c) hydrotreating at least a portion of the second reaction zone effluent of step b) above in a third reaction zone operated under effective hydrotreating conditions and in the presence of hydrogen-containing treat gas and a third catalyst selected from hydrotreating catalysts comprising about 1 to 25 wt. % MoO3, about 0.1 to 6 wt. % CoO wherein said CoO and MoO3 are present in an atomic ratio of about 0.1 to about 1.0 Co/Mo, and said third catalyst has a median pore diameter of about 75 Å to about 175 Å, wherein said third catalyst has a MoO3 surface concentration of about 0.75×10−4 to about 2.5×10−4 g/m2 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.

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, nitrogen-containing compounds, and olefins in a first reaction zone operated under conditions effective to remove at least a portion of said nitrogen-containing compounds with a first catalyst selected from Amberlyst and alumina to produce a first reaction zone effluent having less than 10 wppm total nitrogen;
• b) contacting said first reaction zone effluent in a second reaction zone operated under effective hydroisomerization conditions selected to cause skeletal isomerization of said olefins contained in said feedstream and in the presence of hydrogen-containing treat gas with a second 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 second reaction zone effluent having a higher ratio of iso-olefins to n-olefins than the naphtha boiling range feedstream;
• and
• c) hydrotreating the second reaction zone effluent of step b) above in a third reaction zone operated under selective hydrotreating conditions and in the presence of hydrogen-containing treat gas and a third catalyst selected from supported hydrotreating catalysts comprising about 3 to 6 wt. % MoO3, about 1 to 3 wt. % CoO wherein said CoO and MoO3 are present in an atomic ratio of about 0.25 to about 0.72 Co/Mo, and said third catalyst has a median pore diameter of about 80 Å to about 150 Å, wherein said second catalyst has a MoO3 surface concentration of about 1×10−4 to 2×10−4 g/m2 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.