Modelling of gas-liquid reactors - stability and dynamic behaviour of a hydroformylation reactor, influence of mass transfer in the kinetics controlled regime

On behalf of the development of new hydroformylation reactors, a research p roject was initiated to examine the dynamics of hydroformylation processes. The current paper presents the results of applying the rigorous reactor mo del (van Elk et al., Chem. Engng. Sci. 45 (1999) 4869-4879; Chem. Engng. J. 76 (2000) 223-237) and the approximate reactor model (van Elk et al., 1999 ) on a new, to be developed, hydroformylation reactor with complex kinetics . The reaction considered is of the first order in the olefin and the catal yst concentration, while the apparent reaction order in hydrogen varies bet ween 0 and 1 and in CO between - 1 and 1, depending on the hydrogen and car bonmonoxide concentrations, respectively. The influence of the cooler desig n and the mass transfer on the dynamic behaviour is investigated in the kin etic controlled regime. It is shown that this reactor will show oscillatory behaviour under certain realistic operating conditions. From stability ana lysis, it was found that the desired steady state (temperature, conversion) exists for a wide range of mass transfer parameters. However, the cases ar e only statically similar, but dynamically show an important difference: fo r some conditions, the steady state is found to be dynamically stable, whil e for others the same steady state is found to be dynamically unstable (lim it cycle). This unusual phenomenon is possible due to the negative reaction order in CO. (C) 2001 Elsevier Science Ltd. All rights reserved.