Ethylene-air mixtures under flowing conditions: a model-based approach to explosion conditions

Propylene oxide, ethylene oxide (EO), methanol, and phthalic anhydride are examples of versatile, widely applied chemical intermediates, produced at elevated temperature and pressure conditions, demanding rigorous safety considerations. Well-known industrial applications in which ethylene at the vapour phase is oxidized with oxygen are the manufactures of vinyl acetate and of EO. Partial oxidation of ethylene is usually performed at elevated temperature and pressure in multitubular cooled reactors where the application of explosive limits experimentally obtained under stagnant conditions could entail a not justified economical handicap. Bearing in mind these considerations, in this paper, we developed a novel physical-mathematical model to predict the ignition and flame-propagation phenomena in the presence of gaseous explosive mixtures. The explicit formulae for the ignition condition and the transition from local reaction to the fully developed explosion were obtained by exploring a broad range of operative conditions. A fairly good agreement was found between the predictions in this study of the oxygen critical concentration corresponding to the explosion point and the results of previous experimental studies performed by different researchers.