Patent attributes
An improved method for desulfurizing a fuel stream such as a diesel stream is disclosed which includes generation of a sulfone oil, the desulfurization of the sulfone oil and the recycling of the resulting biphenyl-rich stream and ultra-low sulfur diesel streams. The method includes combining a thiophene-rich diesel stream with an oxidant to oxidize the thiophenes to sulfones to provide a sulfone-rich diesel stream. Sulfone oil is extracted from the sulfone-rich diesel stream to provide sulfone oil and a first low-sulfur diesel stream The low-sulfur diesel stream is recycled. The sulfone-rich oil stream is combined with an aqueous oxidant-containing stream, such as caustic stream, which oxidizes the sulfones to biphenyls and forms sulfite to provide a second low-sulfur diesel stream.
