VAPORIZATION-INDUCED EXTERNAL DEWETTING OF A CATALYST DURING AN EXOTHERMIC MULTIPHASE REACTION

A heterogeneous model is developed to elucidate the phenomena of dewet ting and hot-spot formation during an exothermic-reaction in a gas-liq uid fixed-bed reactor. The model focuses on processes external to the catalyst and accounts for the mass, energy, and momentum transport, va porization, and reaction on the gas- or liquid-covered catalytic solid surface. For a typical olefin hydrogenation reaction, model predictio ns indicate that the system is external heat- and mass-transfer limite d and that thermokinetic coupling causes steady-state multiplicity. In addition, the effects of the heat of reaction, catalytic activity, li quid-phase volatility, and solid-phase thermal conductivity on the loc ation of the dewetting point and conversion are assessed.