Сверхкритические флюиды. Теория и практика
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2019, N2, pp. 23-30

A.A. Vostrikov, O.N. Fedyaeva, A.V. Shishkin, M.Ya. Sokol

Conjugated Processes of Heterogeneous-Homogeneous Oxidation of Hydrogen in High-Density H2/O2/H2O, H2/O2/CO2 and H2/O2/N2 Mixtures

The peculiarities of hydrogen combustion in its stoichiometric mixtures with oxygen diluted with water vapor, carbon dioxide, and nitrogen at ∼2.6 MPa is investigated for the first time. The experiments were carried out at slow uniform heating (1 K/min) in a tubular stainless steel reactor in which the process occurs via the conjugate heterogeneous (over the reactor wall) and homogeneous (in the volume of the reaction mixture) oxidation reactions. Heterogeneous oxidation of H2 prevailed in the N2 and CO2 media, while homogeneous oxidation was predominant in the H2O medium. Based on time dependencies of temperature rise caused by the exothermic oxidation of hydrogen, it is found that the self-ignition temperature of H2/O2/N2 and H2/O2/H2O mixtures is by about 30 K lower than that of the H2/O2/CO2 mixture. It is shown that a small addition of water to the H2/O2/N2 and H2/O2/CO2 mixtures leads to a decrease in the self-ignition temperature.

Key words: hydrogen, self-ignition, saturated water vapor, carbon dioxide

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