Targeted desulfurization process and apparatus integrating gas phase oxidative desulfurization and hydrodesulfurization to produce diesel fuel having an ultra-low level of organosulfur compounds

Abstract

Desulfurization of hydrocarbon feeds is achieved by flashing the feed at a target cut point temperature to obtain two fractions. A first fraction contains refractory organosulfur compounds, which boils at or above the target cut point temperature. A second fraction boiling below the target cut point temperature is substantially free of refractory sulfur-containing compounds. The second fraction is contacted with a hydrodesulfurization catalyst in a hydrodesulfurization reaction zone operating under mild conditions to reduce the quantity of organosulfur compounds to an ultra-low level. The first fraction is contacted with gaseous oxidizing agent over an oxidation catalyst having a formula CuZnAlOin a gas phase catalytic oxidation reaction zone to convert the refractory organosulfur compounds to SOand low sulfur hydrocarbons. The by-product SOis subsequently removed, producing a stream containing a reduced level of organo sulfur compounds.