O2/CO2气氛下气体燃料可燃极限的基础研究

Flammability limits are usually used for characterizing the combustion stability and fire safety of gas mixtures. The high CO2 concentration changes the flammability limits of gas at O2/CO2 atmosphere. Thus, it is necessary to study the effect of CO2 on the flammability limits. The flammability limits of pure and multi-component gas fuels at O2/CO2 atmosphere were studied in our project. Firstly, the measurements of the flammability limits were performed to present the changes of the flammability limits of oxy-fuels versus carbon dioxide concentrations, oxygen concentrations, gas components, initial temperature and pressure. Then, kinetic simulations were performed to investigate the physical, chemical and thermal radiative effects of CO2 on the flammability limits of gas mixtures. Finally, CFD simulations of ignition were performed to analyze the effects of CO2 on the heat absorption during heating, heat release from combustion and heat loss through radiation. Simple models were developed to predict the flammability limits of oxy-fuels. The present research provide the theoretic guidance of combustion stability and fire safety of oxy-fuels.

燃料的可燃极限是判定燃烧稳定性和安全性的重要依据。O2/CO2气氛下由于高浓度CO2的存在，气体燃料的可燃极限发生改变。因此，有必要开展高浓度CO2对气体燃料可燃极限影响机理的研究。本项目以工业中常见的单组份和复杂组分气体燃料为研究对象，实验研究CO2浓度、O2浓度、燃料的组分、初始温度和压力对气体燃料在O2/CO2气氛下可燃极限的影响规律；建立可燃极限处一维预混火焰的化学反应动力学模型，研究O2/CO2气氛下高浓度CO2的热物理性质、化学反应性和热辐射特性对可燃极限的影响机理；建立可燃极限处真实点火过程数学模型，分析高浓度CO2对混合气物理升温吸热、化学反应放热和热辐射散热特性的影响机理，并基于热理论方法，建立O2/CO2气氛下气体燃料可燃极限的简明预测模型。本项目为提高O2/CO2燃烧的稳定性和安全性提供了理论指导和依据。

O2/CO2气氛下的可燃极限是评估O2/CO2燃烧安全性的重要指标。本项目首先对常见碳氢燃料（C2H6、C2H4、C2H2、C3H8、C3H6、C4H10、C4H8，H2、CO和H2/CO）在O2/CO2气氛下的可燃极限进行了实验研究。然后，理论分析了高浓度CO2的化学反应性、热物性和辐射特性对可燃极限的影响。最后，基于热理论和理查德公式，推导了碳氢燃料在O2/CO2气氛下可燃极限的计算模型。所得结果一方面有利于加强对燃料在O2/CO2气氛下点火过程的认识，另一方面对O2/CO2燃烧器的设计和提高O2/CO2燃烧的安全性具有指导意义。