摘要
This paper provides a calculation method for carbon activity in CO-H2-H2O atmosphere. The thermodynamic parameters （aC）gas （carbon activity in environment） of different compositions at any temperature can be obtained by △G^oT. A theoretical analysis has been conducted into the thermodynamic role of iron and the dependence of possible metal-dusting occurrence on temperature, gas composition and total pressure. In CO-H2-H2O gas mixtures, decreasing the molar fraction of H2O and increasing total pressure expands the temperature region for metal dusting. In CO-H2-H2O gas mixture of different compositions at any temperature and pressure for Fe, depending on relative values of （aC）gas, （aC）Fe3C/Fe and aC= 1, three zones were found to exist.
This paper provides a calculation method for carbon activity in CO-H2-H2O atmosphere. The thermodynamic parameters （aC）gas （carbon activity in environment） of different compositions at any temperature can be obtained by △G^oT. A theoretical analysis has been conducted into the thermodynamic role of iron and the dependence of possible metal-dusting occurrence on temperature, gas composition and total pressure. In CO-H2-H2O gas mixtures, decreasing the molar fraction of H2O and increasing total pressure expands the temperature region for metal dusting. In CO-H2-H2O gas mixture of different compositions at any temperature and pressure for Fe, depending on relative values of （aC）gas, （aC）Fe3C/Fe and aC= 1, three zones were found to exist.
基金
supported by National Natural Science Foundation of China (NO.50675096)
