Kinetic and Modeling Study of the Ethylene Oxychlorination to 1,2-Dichloroethane in Fluidized-Bed Reactors

We present the development and the validation of a new kinetic model for the ethylene oxychlorination reaction, relying on 9 chemical reactions to describe the evolution of 12 species (including 6 major byproducts). A set of 28 kinetic runs was performed over a commercial CuCl2/γ-Al2O3 catalyst in a dedicated tubular flow reactor setup operating in a chemical regime. The design of the experiments, covering the effects of temperature, pressure, C2H4 feed molar fraction, and C2H4/HCl and C2H4/O2 feed molar ratios, was planned according to a composite fractional factorial design. Nineteen adaptive rate constants were successfully estimated by multiresponse nonlinear regression of the experimental data. The resulting kinetic model was able to reproduce the experimental 1,2-dichloroethane yields with relative errors below 10% for most of the kinetic runs. We also report the development of two mathematical models of oxychlorination fluidized-bed reactors, namely the simple two-phase (STP) and the axially dispersed plug-flow (ADPF) model, as well as their comparative validation against industrial data. Being characterized by gas superficial velocities typically higher than the transition velocity and being therefore operated in the turbulent fluidization regime, the performances of commercial reactor units are better predicted by the ADPF rather than by the STP model.