The effect of carbon dioxide on the reactivity of H2/CO oxy-fuel combustion

This work describes the ignition delay time mathematical model using the zero-dimensional reactor under adiabatic and isochoric assumptions. The model includes the contributions of inputs, outputs, and generation terms, excluding diffusion contributions that occur when syngas is used in oxy-combustion; when nitrogen is replaced by carbon dioxide. The role played by H and O radicals in the oxidation of Syngas in combustion and oxy-fuel conditions, as well as how the reactions associated with the consumption and production of intermediate radicals are modified by the presence of CO2, which not only modifies the thermal characteristics but also the chemical characteristics, and even the reaction pathway was evaluated and coupled with GRImech30, which was validated using laminar-burning velocity and resulted in a good fit (R2 = 0.94). This model fits well with the experimental data. The results of the simulations showed that the CO2 content in a pre-mixture increases the ignition delay time due to the combined effect of physical and chemical phenomena, such as heat and mass transport. Furthermore, there was an increase in the heat capacity and the inhibition of propagation and termination reactions with increasing CO2 content. The ignition delay time and thermal contribution index were used to analyze the importance of three general factors: H-2/CO ratio, air-fuel ratio, and CO2 content of the pre-mixture. The thermal contribution index was defined as the ratio of the heat released by a given reaction to the total heat released, which proved very useful for analyzing the kinetic mechanisms of oxidation.