Stability analysis of homogeneous and catalytic reactors

his work focuses on the topic of reactor stability. In Part I, runaway criteria are presented for various types of cooled homogeneous and catalytic reactors. It is shown that runaway in all homogeneous reactor models can be described by a universal criterion, and heat and mass dispersion have a minor impact on the runaway boundary. The runaway limits for catalytic reactors are also determined, and it is found that interphase heat and mass transfer have a profound impact on the shape of the stability boundary. Interphase heat transfer increases the runaway region while intraparticle diffusional resistance decreases it. The effect of side reactions on the runaway boundary is determined by considering the cases of consecutive, simultaneous and consecutive-simultaneous reaction networks. A simple criterion is presented to determine when side reactions can have a significant impact on the runaway boundary.;Part II focuses on the problem of reaction-induced flow instabilities in down-flow packed bed reactors. To determine when and how flow maldistributions and hot spots occur in packed beds, a three-dimensional heterogeneous model for an adiabatic packed bed reactor is developed. The model is analyzed first for the pseudohomogeneous case when the particle Damkohler numbers approach zero. The stability boundary of the uniform flow is determined with respect to two- and three-dimensional perturbations. Bifurcation theory, orthogonal collocation and continuation techniques are combined to determine the nonuniform solutions along with their stabilities. For the heterogeneous case with finite particle Damkohler numbers, analysis of the one-dimensional model shows that isolated high temperature branches exist for the adiabatic reactor when the particle Lewis number (Le) is less than unity. The maximum temperature on the isolated branch is determined to be not greater than...