Comparison of the effect of Н₂О and СО₂ additives on the conversion of methane into synthesis gas

For the first time, detailed kinetic modeling of the behavior of undiluted mixtures of methane with oxygen with СО₂  and Н₂О additives was carried out taking into account the formation of microheterogeneous soot particles in the temperature range 1500–1800 K at a pressure of $P_{50}=1$ bar. The appearance of soot particles was observed for rich mixtures, starting with the equivalence ratio $\varphi =\mathrm{3,33}$. At the lower limit of the studied temperature range $T_{50}=1500$ K, a small amount of soot particles (less than 1 %(mass) of C atoms) is formed, and they do not have a significant effect on the other parameters of the reacting system. A noticeable effect of soot particles at $T_{50}=1500$ K is observed for $\varphi =8.0$. This is most clearly manifested in the fact that the temperature profile of the process changes markedly. When water is added, two maxima are observed on it at times of the order of 0.01 and 0.1 s. In the case of CO₂  additives, the second maximum is almost not pronounced. A complex temperature profile leads to the appearance of a second maximum concentration of hydroxyl OH radicals at $~\mathrm{0,1}$ s.