Method for producing sulfur

The invention relates to a process device: comprising a Claus reaction furnace, a Claus waste heat boiler and SO ₃ A decomposition section and a claus conversion section, wherein the claus reaction furnace has an inlet and an outlet, the claus waste heat boiler has a gas inlet, a gas outlet and optionally an elemental sulfur outlet, SO ₃ The decomposition section has a gas inlet and a gas outlet, the claus conversion section has a gas inlet, a gas outlet, and an elemental sulfur outlet, and wherein the inlet of the claus reaction furnace is configured to receive a feed gas, sulfuric acid, fuel, oxidant, and optionally a sulfuric acid atomization medium, and the outlet of the claus reaction furnace is configured to be in fluid communication with the inlet of a claus waste heat boiler, wherein the outlet of the claus waste heat boiler is configured to be in fluid communication with the SO ₃ The inlet of the decomposing field is in fluid communication with SO ₃ The outlet of the decomposition section is in fluid communication with the inlet of the claus conversion section. The process has the associated benefit that it avoids undesirable poisoning of the claus catalyst (sulfation) and contamination of the elemental sulphur product with sulfuric acid in the claus conversion stage.