非平衡条件下甲烷部分氧化反应体系的温度特征

根据对ＣＨ４－Ｏ２在热力学上反应特征的分析，采用镍负载型催化剂Ｎｉ／ＲＭＡ，较详细地研究了甲烷部分氧化制合成气反应体系的非平衡态和温度特征。结果表明，在低温高空速时，产物合成气含量可以明显超过热力学理论值。其原因之一是，催化剂床层存在局部热点温度，使床层实际温度明显高于测定指示温度；第二，反应在低温高空速时处于非平衡态，反应达到平衡前更有利于生成合成气。在６５０～８５０℃高温之间时，通过准确控制反应体系的温度，甲烷转化率和合成气收率可以接近热力学理论平衡值。当温度较高时，在催化剂上方空间将发生甲烷燃烧反应

Temperature characteristic in partial oxidetion of methane under non equilibrium conditions

Based on analysis of the thermodynamic behaviors of CH 4-O 2reaction, the non equilibrium state and temperature characteristics of the reaction system have been investigated for partial oxidation of methane to syngas over a supported nickel catalyst in a fixed bed flow reactor. The results show that, at low temperature and high space velocity,the content of synthesis gas in the product is obviorsly higher than that predicted by thermodynamic calculation.This conflicting conclusion comes out of the facts that the effect of “hot spot”temperature existing in the catalyst bed makes the actual bed temperature significantly higher than the predicted, and that the reaction is carried out under non equilibrium conditions at low temperature and high space velocity, favourable for formation of synthesis gas before the equilibrium state is reached.If the reaction is carried out at higher temperatures of 650 850℃,CH 4 conversion and synthesis gas yield can reach the theoretical values by accurately controlling recation temperatures of the system.When the reaction temperature is much higher, methane burning reaction will occur in the region above the catalyst bed.