Effect of hydrogen additives on the self-ignition of rich oxygen methane-propane mixtures

The effect of small hydrogen additives on the ignition of rich oxygen methane-propane mixtures, which imitated associated petroleum gas, was studied at elevated pressures in a static reactor. The experiments showed that the additions of hydrogen increased the ignition temperature of the mixtures by approximately 140 K; that is, they inhibited the ignition of hydrocarbon mixtures at low temperatures. However, on the contrary, the small additions of hydrogen at higher temperatures promoted their ignition. The additions of hydrogen significantly increased the manifestation of a negative temperature coefficient of reaction rate in the ignition of hydrocarbons. A comparison of the experimental data with the results of calculations performed using kinetic programs showed the need for the considerable expansion of a detailed mechanism in the domain of existence of the negative temperature coefficient of the reaction rate of hydrocarbon oxidation.