FEATURES OF AUTOIGNITION OF METHANE-HYDROGEN MIXTURES

A.V. Arutyunov^1*, A.A. Belyaev¹, K.Ya. Troshin¹, A.V. Nikitin^1,2, V.S. Arutyunov^1,2

¹N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Scinces

²Institute of Problems of Chemical Physics, Russian Academy of Scinces

^*aarutyunovv@gmail.com

Due to the growing interest in the use of hydrogen and mixtures containing it as a motor fuel, including for internal combustion engines, an analysis of the motor characteristics of such fuels is necessary. This work presents the results of experimental studies and kinetic modeling of autoignition of methane-hydrogen-air mixtures in the temperature range of 700-1000 K and pressures of 1-15 atm, relevant to the possibility of undesirable autoignition (detonation) in ICE with spark ignition. A number of interesting phenomena have been discovered related to the autoignition of such mixtures. A significant difference in the temperature dependence of the autoignition delays of methane and hydrogen is shown, associated with fundamental differences in the mechanisms of their oxidation. The causes and mechanism of these differences are discussed, as well as the nature of changes in the mechanisms of methane and hydrogen oxidation that occur near a temperature of 900 K and significantly affect the process of their ignition. The possibility of both promotion and inhibition of methane autoignition by hydrogen additives has been shown. It has been found that the addition of less than 50% hydrogen to methane has little effect on the burning velocity and flame propagation limits, which raises the question of the practical feasibility of realizing the widely discussed possibility of partial conversion of natural gas to hydrogen directly on board the vehicle.

This work was performed within the framework of the Programs of Fundamental Research of the Russian Academy of Sciences of FRCCP RAS on the topic “Chemical aspects of energy; modeling of oxidation and combustion processes” and IPCP RAS on the topic number 0089-2019-0018.