Efficiency of a Claus furnace in the coke-oven gas desulphurization circuit of MMK

Resumo

The poor efficiency of the Claus furnace in sulfur removal at the coke plant of OAO Magnitogorskii Metallurgicheskii Kombinat (MMK) is analyzed on the basis of monitoring data for the sulfur recovery unit and thermodynamic calculations. The low level of sulfur removal from coke-oven gas (~60%) at OAO MMK is mainly due to thermodynamic limitations on the thermal stage of hydrogen-sulfide oxidation with the specific composition of the sour gas at coke plants: low hydrogen-sulfide concentration and combustion of the additional fuel (natural gas). With the kinetic constraints in the Claus furnace, the high CO₂ content in the sour gas (up to 37 vol %) results in increased yield of carbonyl sulfide (~14%). That calls for particular care in optimizing the temperature during the catalytic stages and selecting the best catalysts.