Study on the lower flammability limit of H₂/C₂H₅OH mixture based on chemical kinetics

Research on the lower explosion limit (LFL) of H₂/C₂H₅OH mixture at elevated pressures and temperatures is essential for the safe production of ethanol to hydrogen process. However, the research on the LFL of mixture at high pressures and temperatures is not sufficient, and no effective model has been established. In this work, the influences of pressure, concentrations and temperature on the LFL of H₂/C₂H₅OH mixture had been investigated experimentally and numerically. The experimental results show that, the content of H₂ in the H₂/C₂H₅OH mixture system is positively correlated with LFL, and initial pressure is more sensitive parameter than initial temperature under this mixture conditions. Computational simulation demonstrates that the difference in sensitivity coefficients is closely related to reaction pathway, representing the sensitivity of elementary reactions. The change in hydrogen concentration will alter the reaction pathway, leading to the sensitivity coefficient transforms in the opposite direction. Moreover, the applicability of Le Chatelier's rule and Bartknecht's prediction model to the LFL of H₂/C₂H₅OH mixture was discussed. And the crucial radical groups affecting the LFL of H₂/C₂H₅OH mixture at elevated pressures and temperatures conditions have also been deeply studied. Finally, an LFL prediction model is established based on the crucial radical by machine learning, enabling a useful experimental and theoretical reference for safety production under related conditions.