Ignition delay times of C2H4, C2H4/n-C4H10, and n-C4H10/i-C4H10 under O-2/CO2 atmospheres: Shock tube experiments and kinetic model

Oxy-fuel combustion of fossil fuels based on the Allam cycle has garnered increasing attention owing to its high-power cycle efficiency in carbon capture. The submechanism of ethylene, an important intermediate product in the oxidation of long-chain alkanes, is vital for establishing chemical kinetic models of alkanes for oxy-fuel combustion. In this study, the ignition delay times of C 2 H 4 diluted in CO 2 are measured at pressures of 1 and 10 atm under O 2 /CO 2 atmospheres at three equivalence ratios (0.5, 1.0, and 2.0) in a shock tube. Meanwhile, the ignition delay times of C 2 H 4 / n -C 4 H 10 mixtures and n -C 4 H 10 / i -C 4 H 10 mixtures diluted in CO 2 are measured at pressures of 1 and 10 atm, equivalence ratios of 1.0, and three mixing ratios (1:2, 1:1, and 2:1). The C 2 H 4 submechanism in the Oxymech2.0 Plus model proposed in our previous study is modified by updating some C 2 H 4 -related reactions. The modified Oxymech model, NUIGMECH1.1, and Wang2021 are evaluated based on the present experimental ignition delay times and other experimental results from the literature, including the ignition delay times of C 2 H 4 diluted in both CO 2 and conventional atmospheres, as well as the laminar flame speeds of C 2 H 4 and C 2 H 4 profiles in pyrolysis. The results show that the modified Oxymech model accurately predicts the experimental results. The modified Oxymech model is compared with NUIGMECH1.1 to predict the ignition delay times in CO 2 atmospheres and laminar flame speeds more accurately. The effects of CO 2 on the ignition delay of C 2 H 4 are discussed comprehensively. (c) 2023 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

In this study, the ignition delay times of C2H4 diluted in CO2 were measured to investigate its submechanism in oxy-fuel combustion and the effects of CO2. The modified Oxymech model accurately predicted the experimental results and showed better performance than the NUIGMECH1.1 model. The comprehensive effects of CO2 on the ignition delay of C2H4 were discussed.