The growing energy demand worldwide is currently supplied by the direct use of fossil fuels, which are limited in nature and represent an environmental concern. Syngas/oxy-combustion technologies have become popular due to recent advances in carbon capture and storage and the possibility to avoid NO_X formation by replacing N₂ with supercritical CO₂. However, the successful implementation of these systems faces several drawbacks: variability in syngas composition and lack of understanding of the chemical kinetics at elevated temperature and pressures in the presence of CO₂. In this work, we carried out a molecular dynamics study of syngas oxy-combustion using ReaxFF force field. Three main initiation reactions were identified: H₂ + O₂ → HO₂ + H, H₂ → H + H, and CO₂ → CO + O, with the last being dominant at high temperatures and high concentrations of CO₂. We also found that increasing the initial CO₂ concentration and decreasing that of O₂ delays ignition. However, for enriched CO₂ mixtures, this substrate exerts a catalytic effect in the reactions H₂ → H + H and H₂O → OH + H by forming the intermediate HCO₂. In the absence of initial CO₂, formyl radical (HCO) chemistry is lacking due to the prominent consumption of H species by molecular oxygen via O₂ + H → OH + O and H + O₂ (+M) → HO₂ (+M). However, we observed the association between HCO and OH radicals to form stable formic acid, a reaction not implemented in syngas mechanisms.

目前，全球范围内不断增长的能源需求是通过直接使用化石燃料来满足的，而化石燃料的性质有限并且代表着对环境的关注。合成气/氧气燃烧技术由于碳捕获和储存的最新进展以及通过用超临界CO ₂代替N ₂避免形成NO _X的可能性而变得流行。然而，这些系统的成功实施面临几个缺点：合成气组成的可变性以及缺乏对在存在CO ₂的情况下在升高的温度和压力下的化学动力学的理解。在这项工作中，我们使用ReaxFF力场进行了合成气氧燃烧的分子动力学研究。确定了三个主要的引发反应：H₂ + O ₂ →HO ₂ + H，H ₂ →H + H和CO ₂ →CO + O，最后一种在高温和高浓度CO _2中占主导地位。我们还发现增加初始CO ₂浓度和降低O ₂浓度会延迟点火。但是，对于富集的CO ₂混合物，该底物通过形成中间体HCO ₂在反应H ₂ →H + H和H ₂ O→OH + H中发挥催化作用。在没有初始CO ₂的情况下，由于分子氧通过O ₂ + H→OH + O和H + O ₂（+ M）→HO ₂（+ M）显着消耗H物种，因此缺乏甲酰基自由基（HCO）化学。但是，我们观察到HCO和OH自由基之间的缔合形成稳定的甲酸，该反应未在合成气机理中实施。