甲烷和氢气混合气体金属尘化腐蚀的热力学分析  

Thermodynamic Analysis of Metal Dusting in CH_4-H_2 Atmosphere

作　　者：雷娜[1] 周昌玉[1] 胡桂明[1] 陈成[1] 

机构地区：[1]南京工业大学机械与动力工程学院

出　　处：《石油与天然气化工》2009年第5期456-458,462,共4页Chemical engineering of oil & gas

基　　金：国家自然科学基金(50675096)资助

摘　　要：石油化工、天然气工业、煤气转化及热处理等具有饱和碳气氛的加热转化设备时常发生金属尘化腐蚀,造成重大的经济损失。本文运用化学热力学理论与方法对CH4-H2气氛下发生金属尘化时的吉布斯函数ΔG0T进行计算,从而得到气氛碳活度(αc)gas与温度T的关系式。通过气氛碳活度(αc)gas与材料碳活度(αc)Fe3C/Fe的比较,得到两种金属尘化类型。CH4-H2气氛碳的化学势受温度、气氛组成、总压的影响,减少CH4的含量,降低总压,会使发生金属尘化的温度范围扩大。通过这些分析结果,从理论上解释了金属尘化的发生,并进而推断出尘化发生的条件。Metal-dusting has been reported widely in petrochemical, natural gas, heat-treating and coal-gasification components, etc., which causes heavy economic loss. The relationship between (αc)gas (carbon activity) and T (thermodynamics temperature) was deduced by calculating ΔG0T(standard Gibbs free energy of formation) of CH4-H2 reaction with theory and methodology of chemical thermodynamics. Two types of metal dusting can be found by comparing (αc)gas with (αc)Fe3C/Fe. A theoretical analysis has been conducted into the thermodynamic role of iron and the dependence of possible metal-dusting occurrence on temperature, volumetric ratios of carburizing species CH4, and total pressure. Reducing the volumetric ratio of CH4 and total pressure expands the temperature regime for metal dusting. From the results of analysis, the process of metal dusting on iron in CH4-H2 can be explained in theory and the condition of metal dusting can be deduced further.

关 键 词：金属尘化 热力学 碳活度 化学势 

分 类 号：TG179[金属学及工艺—金属表面处理]