Investigation of the ignition temperature of ethane-air mixtures at elevated pressure

Abstract

Determining the ignition temperature of combustible substances is crucial in enhancing energy utilization efficiency and preventing fire and explosion accidents. This study investigates the ignition temperature of ethane-air mixtures with concentrations of 29.6%, 31.8%, and 34.4% at pressures up to 1 MPa in a 20 L spherical closed vessel, using a “heating” method. The high-pressure gas mixture was heated until spontaneous rapid reaction occurred in the reaction vessel. The study found that the ignition temperature of ethane in air decreases with an increase in initial pressure and ethane concentration. For example, at an ethane concentration of 31.8%, the ignition temperature decreased from 374℃ to 296℃ when the pressure increased from 0.3 MPa to 1 MPa. Additionally, larger container sizes resulted in lower ignition temperatures for ethane. Furthermore, the study simulated the self-oxidation reaction of ethane using the San Diego Mechanism kinetic reaction mechanism. The results revealed that the initial pressure's effect on important free radical reaction rates was the fundamental cause of autoignition. Under high-pressure conditions, the reaction between C2H5 and oxygen, C2H5 + O2<=>C2H4 + HO2, was the most critical reaction pathway. Overall, this study provides valuable insights into the ignition temperature of ethane-air mixtures and identifies key factors that influence autoignition. The findings can be utilized in improving safety measures and optimizing energy utilization in various industrial processes.