MODELING THE MODIFIED CLAUS PROCESS REACTION FURNACE AND THE IMPLICATIONS ON PLANT-DESIGN AND RECOVERY

The calculation of product composition, flow rate and temperature of the modified Claus process reaction furnace is typically done by assuming either thermodynamic equilibrium or by empirical methods fitted to plant data. This paper extensively reviews the literature on the Claus reaction furnace and compares equilibrium and empirical results of the predicted concentrations of the key components: hydrogen (H-2), carbon monoxide (CO), carbonyl sulphide (COS) and carbon disulphide (CS2). The implication of the reaction furnace model on the overall plant design and sulphur recovery is subsequently presented. It is well known that results of equilibrium calculations do not match plant data taken both before and after the waste heat boiler (WHB). Moreover, even though results of empirical methods do not match plant data taken before the WHB, one empirical method provides the best fit of highly scattered data taken after the WHB and provides a conservative plant design and estimates of sulphur recovery and emissions.