Effects of ethylene addition and dilution on the explosion characteristics of ethane-ethylene mixtures

Abstract

The properties of an ethane-ethylene mixture were analyzed under varying equivalence ratios (ranging from 0.58 to 1.4) and ethylene volume fractions (ranging from 0% to 100%) with varying dilution ratios, using a 20-liter apparatus. The study aimed to understand the explosion characteristics of the mixture and to identify the elementary reactions that have the most significant impact on the rise in pressure and ethylene consumption during the explosion process. The results showed that adding ethylene increases the maximum explosion pressure and broadens the flammability limit range. In addition, the work investigated the effects of diluting the mixture with either nitrogen or carbon dioxide. It was found that carbon dioxide has a higher specific heat capacity compared to nitrogen, which enhances the heat absorption capacity of the mixture. The collision of carbon dioxide molecules with the activated radicals in the reaction transfers energy from the radicals to carbon dioxide, reducing the radicals' activity and causing a more significant dilution effect than nitrogen. Finally, a chemical kinetics analysis of the premixed gas using the UC San Diego mechanism revealed that the production rate of key free radicals gradually increases with the addition of ethylene, enhancing the explosion reaction intensity.