O2/CO2循环燃烧方式下矿物元素蒸发特性的热力学研究

The facility for analysis of chemical thermodynamics (F*A*C*T) based on the Gibbs energy minimization principle was used to characterize the evaporation of mineral elements of coal in O2/CO2 recycle combustion. The effects of atmosphere and temperature on the speciation of mineral species were discussed. The results show that Na(K)Cl(g), FeO(g) and SiO(g) are dominant gaseous species of mineral elements. The dominant species of mineral elements in flue gases depend on both the combustion conditions (reducing or oxidizing) and the atmosphere. In O2/CO2 mixture combustion, the evaporation rate of mineral elements is much lower than that in air combustion, especially in reducing atmosphere. The total evaporation of mineral elements in O2/CO2 atmosphere and air combustion under reducing conditions is 4.46% and 9.65%, respectively,up to temperature of 2400 K. The calculation values are consistent with the experiment values. The decrease of mineral elements evaporation is helpful to suppress the formation of fine particle matter and the tendency of initial ash deposition.