EFFECTIVENESS FACTOR FOR A NONISOTHERMAL SIMPLE CATALYTIC REACTION WITH COMBINED TRANSPORT PROCESSES - MAXWELL-STEFAN APPROACH

A two-step procedure is developed and tested for the prediction of eff ectiveness 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 compon ent is obtained. The knowledge of these dependences allows then all th e dependent variables in the catalyst pellet mass and heat balances to be expressed by this concentration. In the second step, a single bala nce differential equation is solved and the effectiveness factor is ob tained. In addition, a deeper insight into the concentration and tempe rature conditions inside the pores is gained. Information of this kind can cast light on some features of the catalytic reactor behaviour. T he analysis of ammonia synthesis illustrates this point.