摘要
催化燃烧作为一种高效清洁的燃烧技术,越来越引起各界的关注,世界各国对催化燃烧进行了大量的研究工作。本文就甲烷在低浓度条件下的催化燃烧进行了实验研究。
分析了气体燃料多孔介质中的催化燃烧的机理,多孔介质中燃烧反应分为催化剂表面反应和空隙中的均相反应,表面反应由于催化剂的参与,其反应速度大约是均相反应速度的26万倍。催化反应通过改变反应的路径,降低反应的活化能,加快了反应速度。多孔介质具有良好的热稳定性,比较高的机械强度和化学稳定性,在催化燃烧过程中既作为催化剂载体,又起到了预热进气和稳定燃烧温度作用。
设计了多孔介质催化燃烧实验装置。采用浸渍法制备了碳化硅蜂窝陶瓷载体稀土催化剂。
对多孔介质阻力进行了冷态实验研究。测量了不同风速和孔径条件下阻力的大小。结果表明:在多孔介质内气流速度较低时,流动阻力成线性增加;在气流速度较高的时,阻力迅速增加。
对低浓度甲烷进行了催化燃烧实验研究。实验测量了催化燃烧温度,催化燃烧尾气排放,并根据进气甲烷浓度和尾气排放浓度,计算了甲烷的催化燃烧的转化率。结果表明:从200℃到400℃催化活性明显上升,甲烷的燃烧转化率从92%上升到98%,500℃-800℃催化燃烧活性高且稳定,甲烷转化率达到99%以上。
As a clean and highly efficient combustion technology, catalytic combustion has be attracted more and more attention and was thorough research in the world. In the paper catalytic combustion of the lean methane was researched.
It was analyzed that catalytic combustion mechanism in porous media. Combustion reaction in porous media consists of catalytic surface reaction and homogeneous reaction. As a result of the participation of the catalyst, catalytic surface reaction rate is about 260,000 times homogeneous reaction rate. Catalytic reaction speeds up the reaction rate by changing the path of reaction and lowering reaction activation energy. Porous media which has a good thermal stability, relatively high mechanical strength and chemical stability,have the role of the catalyst carrier and the stability of combustion temperature.
Device as the fundamental equipment together with the gas system, catalytic combustion burner device and test system was established. Rare Earth catalysts with Silicon carbide honeycomb support were prepared.
The cold resistance test experiment was measured. In different conditions of wind speed and aperture size the resistance was carried out, the resistance loss of the porous media was calculated. The results show: flow resistance is linear increase when flow speed is low; flow resistance is rapid increase when flow speed is high in porous media.
Methane Rare Earth catalyst combustion experiment was carried out. Catalyst combustion temperature and composition of fuel exhausts were measured and methane conversion was calculated. The results show that methane conversion was above 92% from 200℃to 400℃,methane conversion is above 99% from 500℃to 800℃.
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