Kinetic model for calcium sulfate decomposition at high temperature  

硫酸钙高温分解的动力学模型（英文）

作　　者：闫志强[1] 王泽安[1] 王小锋[1] 刘豪[1] 邱建荣[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第10期3490-3497,共8页中国有色金属学报（英文版）

基　　金：Project(51276074)supported by the National Natural Science Foundation of China;Project(2014NY008)supported by Innovation Research Foundation of Huazhong University of Science and Technology,China

摘　　要：A modified shrinking unreacted-core model,based on thermogravimetric analysis,was developed to investigate CaSO4 decomposition in oxy-fuel combustion,especially under isothermal condition which is difficult to achieve in actual experiments due to high-temperature corrosion.A method was proposed to calculate the reaction rate constant for CaSO4 decomposition.Meanwhile,the diffusion of SO2 and O2,and the sintering of CaO were fully considered during the development of model.The results indicate that the model can precisely predict the decomposition of CaSO4 under high SO2 concentration（1100×10-6）.Concentrations of SO2 and O2 on the unreacted-core surface were found to increase first and then decrease with increasing temperature,and the average specific surface area and porosity of each CaO sintering layer decreased with increasing time.The increase of SO2 and/or O2 concentration inhibited CaSO4 decomposition.Moreover,the kinetics of CaSO4 decomposition had obvious dependence on temperature and the decomposition rate can be dramatically accelerated with increasing temperature.基于硫酸钙程序升温实验计算并得到其煅烧反应速率常数,综合考虑SO2与O2的表面扩散以及煅烧分解产物氧化钙的烧结过程,建立修正的硫酸钙分解未反应缩核模型。结果表明,硫酸钙的高温分解对温度非常敏感,提高SO2和O2的分压/抑制硫酸钙的高温分解。随着分解反应的进行,氧化钙烧结产物层的平均比表面积和平均孔隙率逐渐降低,同时未反应核表面SO2和O2浓度先增大后减小,在高SO2浓度(>1100×10-6)条件下模拟计算结果与实验值吻合良好。

关 键 词：oxy-fuel combustion shrinking unreacted-core model CASO4 DECOMPOSITION CaO sintering 

分 类 号：O614.231[理学—无机化学]