US Patent 8043597 Process and apparatus for the combustion of sulfur

A process for a combustion of sulfur with an oxygen-containing gas to produce sulfur dioxide. The process includes introducing the sulfur and the oxygen-containing gas to a furnace. The sulfur is evaporated and subsequently a portion of the sulfur is oxidized to sulfur dioxide under sub-stoichiometric conditions in a first portion of the furnace. The sulfur dioxide formed in the first furnace portion is introduced together with any unoxidized sulfur to a second portion of the furnace which is disposed adjacent to the first furnace portion. The sulfur dioxide and unoxidized sulfur are subjected to post-combustion with the oxygen-containing gas in an inlet of a downstream waste heat boiler.