Calculation of effectiveness factor for multiple claus reactions with single‐step rate‐controlling

Abstract

Most of the bountiful literature on the calculation of effectiveness factors for catalyst particles deals with relatively simple reactions and kinetics. The performance of catalyst particles in the industrially important, modified Claus reaction introduces multiple reactions, sulphur vapour equilibria, non‐linear kinetics and limiting thermodynamic conversions into the calculation of local effectiveness factors. This analysis demonstrates a means for generating local effectiveness factors, during reactor design calculations by the use of a single calculated curve of versus a modified Thiele parameter for spherical particles.

Effect of Catalyst Shape on the Hydrolysis of COS and CS2 in a Simulated Claus Converter

“…The reversible catalytic reaction (2) is the main reaction carried out in the presence of alumina catalyst. Its intrinsic rate function is defined in the thermodynamically consistent form where K ) K E , as originally developed by Dalla Lana et al (1976) and subsequently extended by Razzaghi and Dalla Lana (1984). The thermodynamic equilibrium constant, K E , and the adsorption constant for water vapor, K H2O , are always evaluated at the local temperature during the integration of the equations.…”

“…The value for the Thiele modulus influences the effectiveness factor somewhat inversely, as shown in For the Claus reaction (2), the rate constant, k s , in rate equation ( 16) is not defined for a first-order function. The Thiele modulus is calculated from the following differential equation for an isothermal spherical Claus catalyst pellet (Razzaghi and Dalla Lana, 1984):…”