Naptha HDS
Most catalytic reforming catalysts contain platinum as the active material. Sulfur and nitrogen compounds will deactivate the catalyst and must be removed prior to catalytic reforming. The Naphtha HDS unit uses a cobalt-molybdenum catalyst to remove sulfur by converting it to hydrogen sulfide that is removed with unreacted hydrogen.
Reactor conditions are relatively mild for Naphtha HDS at 400-500˚F (205-260˚C) and relatively moderate pressure 350-650 psi (25-45 bar). As coke deposits on the catalyst, reactor temperature must be raised. Once the reactor temperature reaches ~750˚F (400˚C), the unit is scheduled for shutdown and catalyst replacement.
If required, the boiling range of the Catalytic Reforming charge stock can be changed by redistilling in the Naphtha HDS. Often pentanes, hexanes and light naphtha are removed and sent directly to gasoline blending or pretreated in an Isomerization Unit prior to gasoline blending.
