c 411sm3 form trilobe extrudate nominal size 1 2 mm 1 2 mm metal wt cobalt 2 5 u2014 molybdenum 5 20 21 5 nickel u2014 3 5 support alumina alumina the conditions suitable for the hydrogenation of substantially all of the unsaturated compounds in a distillation column reactor are considerably more severe than for selective hydrogenation of acetylenes and diolefins which has been practiced in the past hydrogen partial pressures in the range of 100 200 psia are anticipated these hydrogen partial pressures are still considerably less than would be expected in standard downflow trickle bed reactors the reaction temperature is that temperature where the material is boiling within the catalyst bed at the appropriate total pressure that yields the desired hydrogen partial pressure the conditions suitable for the desulfurization of naphtha in a distillation column reactor are very different than those in a standard trickle bed reactor especially with regard to total pressure and hydrogen partial pressure typical conditions in a reaction distillation zone of a naphtha hydrodesulfurization distillation column reactor are temperature 450 700 u00b0 f total pressure 75 300 psig h 2 partial pressure 6 75 psia lhsv of naphtha about 1 5 h 2 rate 0 1000 scfb the operation of the distillation column reactor results in both a liquid and vapor phase within the distillation.