Oxidative dehydrogenation of ethane in an electrochemical packed-bed membrane reactor: Model and experimental validation

A model was developed for the electrochemical oxidative dehydrogenation of ethane to ethylene in a solid electrolyte membrane reactor. Experimental data from the process with oxygen being supplied either electrochemically or gaseously were used in the model validation. In the model description, the converse axial distribution of the oxygen concentration in the reactor operated in the co-feed modus as well as in the electrochemical membrane modus was taken into account. The conversion of ethane and the selectivity to the desired product ethylene were well predicted with the model that included the kinetic equations based upon the Mars-van-Krevelen or the Langmuir-Hinshelwood mechanisms for investigations in the co-feed modus with gaseous dioxygen. This model was not directly applicable for the conditions of an electrochemical membrane reactor. The kinetics of the oxygen reduction on the cathode, the transfer of oxygen ions from the cathode to the anode, as well as the formation of the gaseous dioxygen on the anode, were therefore included in the model. Furthermore, the model for the electrochemical operation was extended by two additional side reactions that describe the electrochemically induced oxidation of the intermediate ethylene. After this, the experimental data measured in the temperature range of 540-620 degrees C agreed well with the predictions of the extended model. (c) 2008 Elsevier B.V. All rights reserved.