CO2和N2惰化条件下合成气可燃下限实验研究

利用自主搭建的可燃极限实验系统，对含有CO₂和N₂的合成气可燃下限进行实验研究，并对Le Chatelier公式进行校核.结果表明，合成气可燃下限随含氢量的增加而降低，由于反应控制机理的影响效应，少量氢气的加入对混合物可燃下限具有显著影响;合成气可燃下限随N₂和CO₂比例的增加近似线性升高，而CO₂较强的热效应及化学效应使其对混合物可燃下限的影响更显著;由于Le Chatelier在推导过程中对化学反应作用的简化及忽视，使其对含氢量较低及惰化比例较高的合成气可燃下限的预测准确性较差，且计算结果不能区分不同惰性气体对合成气可燃下限的影响差异.

Experimental Study on Lower Flammability Limits of CO2/N2 Diluted Syngas

The lower flammability limits of syngas/air mixtures with CO₂ and N₂ inert dilution were experimentally studied under atmospheric conditions via a self-developed closed cylindrical stainless steel vessel. The experimental data were used to validate the performance of the Le Chatelier’s Rule. The experimental results showed that， the lower flammability limit of fuels mixtures decreases with the increase of H₂ fraction. A small amount of H₂ in the fuels presents the significant effect on the lower flammability limit of mixtures due to the variation of the controlled mechanism of the reaction. The lower flammability limits of mixtures almost linearly increases with an increase in inert dilution ratio. CO₂ has a stronger inert effect than N₂ due to CO₂’s stronger thermal and chemical kinetic effect in reducing the flame temperature and radical concentrations. The prediction by Le Chatelier’s Rule has great discrepancy against the experimental results when H₂ fraction is small or with the high presence of inert species in the mixture. Moreover， the different inter effect between CO₂ and N₂ on the lower flammability limit cannot be calculated using Le Chatelier’s Rule.