Method for production of elemental sulfur by part or fully catalytic oxidation of Claus tail gas

A process for production of elemental sulfur from a feedstock gas comprising from 15 vol %, to 100 vol % H2S and a stream of sulfuric acid, the process comprising

• a. providing a Claus reaction furnace feed stream comprising an amount of said feedstock gas, an amount of sulfuric acid, an amount of oxygen and optionally an amount of fuel, wherein the amount of oxygen is substoichiometric with respect to the Claus reaction,
• b. directing said Claus reaction furnace feed stream to a reaction furnace operating at elevated temperature, providing a Claus converter feed gas,
• c. cooling said Claus converter feed gas to provide a cooled Claus converter feed gas and optionally withdrawing elemental sulfur from the gas,
• d. directing said cooled Claus converter feed gas to contact a material catalytically active in the Claus reaction,
• e. withdrawing a Claus tail gas and elemental sulfur, optionally by cooling the effluent from said material catalytically active in the Claus reaction,
• f. directing a stream comprising said Claus tail gas, oxygen and optionally a fuel as a feedstock gas to a means for sulfur oxidation, providing a SO2 converter feed gas, wherein an amount of combustibles, in the Claus tail gas, is oxidized in the presence of a material catalytically active in sulfur oxidation at an inlet temperature below 400° C.,
• g. directing said SO2 converter feed gas to contact a material catalytically active in SO2 oxidation to SO3, providing an SO3 rich gas,
• h. converting said SO3 rich gas to concentrated sulfuric acid, either by absorption of SO3 in sulfuric acid or by hydration of SO3, cooling and condensation of sulfuric acid,
• i. recycling at least a part of the produced sulfuric acid to the Claus reaction furnace, wherein an amount of the Claus tail gas is directed to an incinerator, providing a combusted Claus tail gas, which is combined with a further amount of Claus tail gas.