Gasoline desulfurization process
AssigneeChemical Research & Licensing Company
InventorsDennis Hearn, Thomas P. Hickey
Life of this patent
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Abstract
A catalytic cracked naphtha is desulfurized with minimum loss of olefins and octane. The naphtha is fed to a first distillation column reactor which acts as a depentanizer or dehexanizer with the lighter material containing most of the olefins and mercaptans being boiled up into a first distillation reaction zone where the mercaptans are reacted with diolefins to form sulfides which are removed in the bottoms along with any higher boiling sulfur compounds. The bottoms are subjected to hydrodesulfurization in a second distillation column reactor where the sulfur compounds are converted to H.sub.2 S and removed. The lighter fraction containing most of the olefins is thus not subjected to the more harsh hydrogenation conditions of the second reactor.
Claims13
A process for removing sulfur from a naphtha boiling range hydrocarbon stream, comprising the steps of:
- (a) feeding a naphtha boiling range hydrocarbon stream containing olefins, diolefins, mercaptans and thiophenes and an effectuating amount of hydrogen to a first distillation column reactor into a feed zone;
- (b) boiling a fraction of said naphtha boiling range hydrocarbon stream containing mercaptans, diolefins and a substantial portion of said olefins upward into a first distillation reaction zone containing a Group VIII metal hydrogenation catalyst suitably supported and spaced in said first distillation column to act as a catalytic distillation structure under conditions to react a portion of said mercaptans with a portion of the diolefins to form sulfides and an overhead distillate product having a reduced mercaptan content;
- (c) removing said sulfides, thiophenes and heavier mercaptans with a higher boiling fraction as bottoms from said first distillation column reactor;
- (d) feeding said bottoms and hydrogen to a second distillation column reactor having a second distillation reaction zone containing a hydrodesulfurization catalyst suitably supported and spaced in said second distillation column to act as a catalytic distillation structure under conditions to react a portion of said sulfides, thiophenes and heavier mercaptans with said hydrogen to form H.sub.2 S;
- (e) removing said H.sub.2 S as a gas from the overheads from said second distillation column reactor;
- and
- (f) recovering a naphtha product from said second distillation column reactor.
Dependencies are inferred from the claim text.