PRODUCTION OF SULFURIC ACID FROM COKE OVEN GAS DESULFURISATION PRODUCT

The present invention relates to a process and a process plant for the production of sulfuric acid (30) from a gas comprising H2S (1) and HCN characterized by the following steps; directing said gas to an alkaline absorber (2) containing a liquid ammonia absorbent solution and a dissolved material catalytically active in oxidation of H2S to elemental sulfur providing a liquid slurry (5) comprising sulfur and coke oven gas absorber liquid, separating at least a portion of said elemental sulfur from coke oven gas absorber liquid by mechanical means of separation as a sulfur sludge(10), combining said sulfur sludge (10) with a support fuel (22) and a first gas comprising oxygen in or upstream an incinerator, incinerating said mixture, providing an incinerated gas comprising SO2 and NOX (19), optionally adding a second gas comprising oxygen to said incinerated gas, selectively removing the formed NOX by chemical reduction with NH3, contacting said process gas (46) with a material (25) active in oxidation of SO2 to SO3 providing an oxidized process gas (28), optionally adding water to said oxidized process gas and condensing concentrated sulfuric acid formed in said oxidized process gas.