NUMERICAL STRATEGIES IN SOLVING GAS-LIQUID REACTOR MODELS .3. STEADY-STATE BUBBLE-COLUMNS

Various numerical solution strategies based on finite difference and o rthogonal collocation discretization were tested in context with a ste ady-state bubble column reactor model. Furthermore the numerical aspec ts of the outlet boundary conditions for the axial dispersion model we re studied. The collocation based algorithms were found to be the most accurate, but also numerically the most sensitive to the reaction kin etics and boundary conditions. The more robust finite difference metho ds are not as sensitive, but considerably more discretization points a re required for an accurate solution. A simple semi-empirical outlet b oundary condition was proposed for the axial dispersion model to overc ome known numerical problems with the Danckwerts' outlet boundary cond ition. The proposed semi-empirical boundary condition was superior to the Danckwerts' boundary condition with all tested kinetics.