Effect of N2/CO2 Dilution Ratios on Explosion Characteristics of Hydrogen/Propane Mixtures

Abstract

With the advancement of hydrogen energy, hydrogen-blended fuels have gained widespread application in industrial and energy sectors, drawing significant attention to the explosion characteristics and safety risks associated with hydrogen/propane (H₂/C₃H₈) gas mixtures. To effectively mitigate these explosion risks, this study investigates the inerting effects of various nitrogen (N₂) and carbon dioxide (CO₂) dilution ratios on H₂/C₃H₈ gas mixtures. The CHEMKIN-Pro software was employed to simulate the explosion and inerting properties of these mixtures, analyzing parameters such as adiabatic explosion pressure, flame temperature, concentrations of key radicals, heat release rate, and sensitivity of elementary reactions. The results indicate that an increase in the CO₂ dilution ratio corresponds to a linear decrease in both the adiabatic explosion pressure and the flame temperature. Furthermore, a higher CO₂ dilution ratio leads to a decline in the heat release rate and the generation rates of H, O, and OH radicals, with the generation rate of H radicals experiencing the most notable reduction. Sensitivity analysis of elementary reactions reveals that reaction R1: H + O₂ = O + OH has the most significant promoting effect, while R410: C₃H₈ + H = H₂ + iC₃H₇ exhibits a pronounced inhibitory effect. CO₂ effectively suppresses and transforms key intermediates through specific reaction pathways (such as R52: CH + CO₂ = HCO + CO and R79: CH₂ + CO₂ = CH₂O + CO), thus reducing the overall heat release rate of the reactions. This study offers important theoretical insights into the inhibitory role of inert gases in H₂/C₃H₈ gas mixtures, providing a foundation for safety management and the advancement of clean energy technologies.