The overall sulphur recovery achieved in conventional Claus units is primarily dictated by the thermodynamic equilibrium of the Claus reaction at the outlet of the final catalytic converter. This thermodynamic equilibrium allows increased sulphur conversions when the temperature is lowered. Conventional Claus reactors are operated at temperatures above the dewpoint of liquid sulphur which limits the achievable conversion to 95-98% (depending on the number of catalytic stages) for typical refinery acid gases.
