Patent ID: 7906013

Claim:
A process to produce low sulfur diesel comprising: (a) converting a hydrocarbonaceous feedstock in a hydrodesulfurization zone containing at least a hydrodesulfurization catalyst operating at conditions effective to produce a hydrodesulfurization zone effluent having a reduced concentration of sulfur; (b) separating the hydrodesulfurization zone effluent in a fractionating zone into at least a diesel boiling range distillate having a reduced concentration of sulfur; (c) dissolving hydrogen in the diesel boiling range distillate, the hydrogen in a form that is available for consumption in a liquid-phase continuous reaction zone; and (d) feeding the diesel boiling range distillate once-through to a liquid-phase continuous reaction zone having a hydrodesulfurization catalyst using the hydrogen dissolved in the distillate at conditions effective to produce a liquid-phase reaction effluent having the low sulfur diesel with an improved cetane number over the diesel boiling range distillate, wherein the diesel boiling range distillate is fed to the liquid-phase continuous reaction zone with an absence of liquid-phase reaction zone diesel effluent recycled from the same liquid-phase continuous reaction zone or any other hydrocarbon stream.