Vasavan Aromal, de Goey Philip, van Oijen Jeroen
Multiphase and Reactive Flows Group, Mechanical Engineering Department, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
Energy Fuels. 2018 Aug 16;32(8):8768-8780. doi: 10.1021/acs.energyfuels.8b01388. Epub 2018 Jul 21.
The ignition delay of biogas in mixing layers is investigated using a one-dimensional combustion model, with its application in Moderate or Intense Low oxygen Dilution (MILD) combustion being the focus. The current study reveals the key aspects of the ignition of biogas in a nonpremixed, igniting mixing layer with a hot oxidizer of low oxygen content. The observed characteristics are contrasted against the existing studies on ignition in homogeneous mixtures under similar conditions. Biogas is considered here as a mixture of CH with variable amounts CO. The influence of reactive, thermal, and transport properties of CO on the ignition is evaluated using artificial species to mimic the respective characteristics of CO. While the ignition delay in homogeneous mixtures shows a strong dependence on CO content in the fuel, the ignition delay predictions from one-dimensional mixing layers show no significant influence of CO levels in biogas. In addition, the influence of oxidizer composition and temperature on ignition delay is determined for CO levels ranging from 0% to 90%. A sensitivity analysis of chemical reactions on the ignition delay shows a negligible effect of CO concentration in biogas. The current study emphasizes the role of oxidizer composition and temperature on the ignition characteristics of a MILD biogas flame.
利用一维燃烧模型研究了混合层中沼气的着火延迟，重点关注其在中低氧稀释（MILD）燃烧中的应用。当前研究揭示了在具有低氧含量热氧化剂的非预混着火混合层中沼气着火的关键方面。将观察到的特性与在类似条件下关于均匀混合物着火的现有研究进行了对比。这里将沼气视为含有不同量CO的CH混合物。使用人工物种来模拟CO的各自特性，评估了CO的反应性、热性质和传输性质对着火的影响。虽然均匀混合物中的着火延迟强烈依赖于燃料中的CO含量，但一维混合层的着火延迟预测显示沼气中CO水平没有显著影响。此外，针对0%至90%的CO水平，确定了氧化剂组成和温度对着火延迟的影响。化学反应对着火延迟的敏感性分析表明，沼气中CO浓度的影响可忽略不计。当前研究强调了氧化剂组成和温度对MILD沼气火焰着火特性的作用。
