MODELING CATALYTIC COMBUSTION IN A MONOLITH REACTOR - A NUMERICAL ALGORITHM FOR VARYING SOLID-PHASE PECLET NUMBERS

The modelling of catalytic combustion in a monolith reactor results in a boundary value problem involving both differential and algebraic eq uations. In the case studied here there is an initial value system of differential algebraic equations coupled to a standard two-point bound ary value problem. The latter equation has the solid phase Peclet numb er (Pe) as a parameter which in the application of interest here can v ary from 10(-1) to 10(4). The aim of the paper is to introduce and ana lyze an iterative solution technique which will treat all Pe values. T he technique is illustrated with the aid of a simplified 1-D single ch annel model but is not restricted to this case and may readily be exte nded to the modelling of multichannel monolith reactors. The solution algorithm is a natural iteration which makes use of the coupling betwe en the differential algebraic initial value problem and the two-point boundary value problem. A convergence theory is given for this iterati on. Example problems are solved and the numerical results are shown to be in agreement with the theory.