Collect. Czech. Chem. Commun. 1998, 63, 252-270

Effectiveness Factor for a Non-Isothermal Simple Catalytic Reaction with Combined Transport Processes: Maxwell-Stefan Approach

Petr Schneider

Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, 165 02 Prague 6-Suchdol, Czech Republic


A two-step procedure is developed and tested for the prediction of effectiveness factors for stoichiometrically simple catalytic reactions. In the first step the dependences of state variables (concentrations, temperature, pressure) on the concentration of the key reaction component is obtained. The knowledge of these dependences allows then all the dependent variables in the catalyst pellet mass and heat balances to be expressed by this concentration. In the second step, a single balance differential equation is solved and the effectiveness factor is obtained. In addition, a deeper insight into the concentration and temperature conditions inside the pores is gained. Information of this kind can cast light on some features of the catalytic reactor behaviour. The analysis of ammonia synthesis illustrates this point.

Keywords: Pore diffusion; Effectiveness factor; Maxwell-Stefan diffusion; Ammonia synthesis.