Detonation of H2–Air–Steam Mixtures: A Potential Hazard in Large-Scale Electrolyzer and Fuel Cell Installations

Abstract

System failure in large-scale electrolyzer and fuel cell installations may cause the formation of explosive H2–air–steam mixtures. Detonation properties (e.g., detonation cell size) and flame dynamics features (e.g., flame acceleration, runup distance, and deflagration-to-detonation transition “DDT”) of these mixtures were investigated experimentally and numerically to gain a more in-depth understanding of the hazards of H2–air–steam under conditions pertinent to PEM-based electrolyzers and fuel cells (temperatures between 50 °C and 80 °C and pressures between 20 and 40 bar). While our results confirm the findings of previous studies in terms of the cooling effects of steam on detonation, we found that operating pressures between 20 and 40 bar counteract the effect of steam, making the H2–air–steam mixture more detonable. This is particularly evident from the experimental data on detonation cell size and runup distance at pressures greater than 20 bar.