Ignition delay times of n-butane and i-butane under O2/CO2 atmospheres: Shock tube experiments and kinetic model

Pressurized oxy-fuel combustion is deemed an advanced oxy-fuel combustion technique due to the lower cost and little decrease in the generating efficiency compared to conventional PC system without CO2 capture. Butane is an important composition of petroleum and natural gas. In this work, the ignition delay times (IDTs) for n-butane and i-butane under O2/CO2 atmospheres were measured in a shock tube at different equivalence ratios (Φ) and pressures. Based on our previous C1 C3 model Oxymech2.0 and the C4 sub-model of Aramco3.0, a chemical kinetic model Oxymech2.0 Plus was updated. Oxymech2.0 Plus was validated by the newly measured IDTs of butane under O2/CO2 atmospheres. The model was also validated by the literature experimental data for IDTs of n-butane and i-butane at O2/Ar and O2/N2 atmospheres, laminar flame speeds of n-butane and i-butane in air, and species profiles of n-butane and i-butane pyrolysis. The comparison between Oxymech2.0 Plus and Aramco 3.0 models was also conducted in detailed. The results show that the updated reactions in the study significantly improve the prediction of IDTs, laminar flame speeds and species profiles of butane in O2/CO2 atmospheres. The effects of equivalence ratios and CO2 on the IDTs of n-butane and i-butane were analyzed.