Modeling and simulation of urea-water-solution droplet evaporation and thermolysis processes for SCR systems

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• 作者：Xubo Gan ; Dongwei Yao ; ^{19880520@zju.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; ^{cyril1205@163.com" class="auth_mail" title="E-mail the corresponding author} ; Feng Wu ; Jiawei Dai ; Lai Wei ; Xingwen Li
• 关键词：SCR ; UWS evaporation ; Urea thermolysis ; Semi-detailed kinetic ; Simulation
• 刊名：Chinese Journal of Chemical Engineering
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：24
• 期：8
• 页码：1065-1073
• 全文大小：1213 K

文摘

A reliable mathematical model of urea-water-solution (UWS) droplet evaporation and thermolysis is developed. The well known Abramzon–Sirignano evaporation model is corrected by introducing an adjustment coefficient considering the different evaporation behaviors of UWS droplet at different ambient temperatures. A semi-detailed kinetic scheme of urea thermolysis is developed based on Ebrahimian's work. Sequentially, the evaporation characteristics, decomposition efficiency of a single UWS droplet and deposit formation are simulated. As a result, the relation of evaporation time, relative velocity, exhaust temperature and droplet initial diameter is presented. Synchronously, it indicates that temperature is the decisive factor for urea thermolysis. Different temperatures result in different deposit components, and deposit yield is significantly influenced by temperature and decomposition time. The current work can provide guidance for designing urea injection strategy of SCR systems.