Conjugated Heterogeneous-Homogeneous Oxidations of Hydrogen in High-Density H_2/O_2/H_2O, H_2/O_2/CO_2, and H_2/O_2/N_2 Mixtures

摘要

The combustion of hydrogen in its stoichiometric mixtures with oxygen diluted with water vapor, carbon dioxide, and nitrogen at 2.6 MPa was studied. The experiments were performed in a slowly and uniformly heated (1 K/min) tubular stainless steel reactor. The process occurred via conjugate heterogeneous (on the reactor wall) and homogeneous (in the reaction mixture) oxidations. The heterogeneous oxidation of H_2 prevailed in N_2 and CO_2, while the homogeneous oxidation was predominant in H_2O. Based on the time dependences of temperature rise caused by the exothermic oxidation of hydrogen, it was found that the self-ignition temperature of the Н_2/О_2/N_2 and Н_2/О_2/H_2O mixtures was ~30 K lower than that of the Н_2/О_2/СО_2 mixture. A small water addition to the H_2/O_2/N_2 and H_2/O_2/CO_2 mixtures led to a decrease in the self-ignition temperature.