An analysis of chemical reactor stability and control-XV The multicomponent spray reactor

Abstract

The objective of this paper is to present a continuous stirred-tank model for processes in which a liquid is sprayed into a gas. In this model a uniform spray of droplets enters the reactor along with one or more gaseous reactants. Both the droplets and the gas are taken to be well-mixed in the reactor. The droplets evaporate and the resulting vapors combine homogeneously with the gaseous reactants. In the multicomponent case the droplets contain a mixture of two or more miscible components. Steady state and transient equations are derived, and the numerical methods of solution are discussed. Steady states are calculated for two-component systems of heptane-octane and hydrazine-water and for a three-component system of heptane-octane-nonane, with oxygen as the gaseous reactant in each case. In addition, a study is made of several parameters of the heptane-octane system. Stability is determined by calculating transients for selected perturbations from the steady states. Incorporated in the reactor model is an analytic model for the fluxes of vapors from a multicomponent droplet which exhibits the augmentation of transfer of one vapor due to the net flux of the remaining vapors. Also presented is an approximate model for the multicomponent spray reactor which gives good results for small droplets and requires only a fraction of the effort needed to solve the complete set of equations.