Ethane partial oxidation has surfaced as a potential alternative considering lower reaction temperature requirement, high conversion, and decrease in coke formation compared to ethane. Several catalysts have been reported in the literature; however, little work has been presented in the past incorporating homogenous chemistry. The influence plays a pivotal role even with a catalytic system when a high temperature operation is anticipated and may stand out under certain process conditions; therefore, it is necessary to corroborate such behavior independently.
The present work focuses on presenting detailed bifurcation analysis of homogeneous axial dispersion model that includes thermal/specie back-mixing and a global kinetic model comprising of seven-reactions/eight-species for homogeneous oxidative dehydrogenation of ethane. Model predictions are compared with literature and obtained experimental data to validate the approach as well as the kinetic constants to determine ethane and oxygen conversion, product distribution profile in terms of selectivity and ethylene yield under various feed ratios, space time and feed temperature. The presence of hysteresis depends on the ethane/oxygen ratio as well as feed temperature and residence time. At high ethane/oxygen ratio or feed temperature, hysteresis might not exist so careful estimation of parameters respecting flammability limits is indispensable. Utilizing exothermic energy from dominating oxidative chemistry to operate reactor auto-thermally (except during start-up) under lumped thermal configuration leveraging thermal back-mixing and considering industrial perspective in mind, space times of milli-second order is desired to comply with reactor volume constraint and ethylene yield between 45~48% is predicted.