Minimum ignition energy of hydrogen-air and methane-air mixtures at temperatures as low as 200 K

The primary objective of this study is to measure the minimum ignition energy (MIE) of methane-air and hydrogen-air mixtures at low temperatures and atmospheric pressure. Initial fuel-air mixture temperatures as low as 200 K were considered, for a constant equivalence ratio of 1.0 for methane-air and 0.16 for hydrogen-air. The ignition source was a spark, generated by a high-voltage pulse of 100 ms duration, applied on two pin electrodes of 0.1-mm diameter, separated by a gap distance of 1 mm. The experimental methodology was validated by comparing the results obtained with those from previous studies avail-able in the literature. First, for methane-air mixtures, the MIE as a function of the equiv-alence ratio followed the same trend at 295 K and 255 K, i.e., its lowest value was obtained for a stoichiometric mixture. Second, when the temperature of the mixture was decreased, the MIE increased linearly for both fuels. The rate at which the MIE changed was higher for hydrogen-air (-7.9 mJ/K) than for methane-air (-3.4 mJ/K). Overall, this study provides valuable information on the MIE of methane-air and hydrogen-air mixtures at low tem-peratures, which can be useful for the design of cryogenic fuel storage systems.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The primary objective of this study is to measure the minimum ignition energy (MIE) of methane-air and hydrogen-air mixtures at low temperatures and atmospheric pressure. The results show that the MIE increases linearly with decreasing mixture temperature, and the rate of change is higher for hydrogen-air mixtures compared to methane-air mixtures. These findings are important for the design of cryogenic fuel storage systems.