On novel processes for removing sulphur from refinery streams

This review discusses some of the processes that have been, or are being, developed as an alternative/addition to present-day hydrodesulphurization processes that are based on (selective) heterogeneous catalysis. The technologies applied in these alternatives range from reactive adsorption, oxidative routes (especially for diesel) and other chemical conversion methods, to “simple” physical separation methods (non-destructive adsorption, extraction, etc.). It is concluded that it appears that for the time being, as long as sulphur levels of 10 ppmw or slightly below are aimed at, the classical hydrotreating options and their off shoots still hold the field of transportation-fuel desulphurization, although a few of the possible alternatives do have achieved commercial status in the gasoline area. If, on the other hand, S in product levels should be as low as <1 ppmw, then polishing processes will come into their own.