Reaction Kinetics of Ammonia Production by Urea Thermal Decomposition by SCR Denitration
Due to the lack of accurate reaction kinetics model,it is difficult to use CFD to optimize the structure and predict the ammonia conversion rate in the design of the urea pyrolysis furnace,which leads to frequent crystal blockage and other problems in operation,seriously restricting the safe and stable operation of the denitrification system.We ex-perimentally studied the conversion rate of CO(NH2)2 to NH3 and HNCO in a tubular reactor at 300～500℃and found that the thermal decomposition rate of CO(NH2)2 and the hydrolysis rate of HNCO were significantly dependent on the reaction temperature and residence time.Then,we calculated the reaction rate of the main two-step reactions,and determined the reaction activation energy and Pre-exponential factor by linear fitting of lnk and 1/T.Taking the pi-lot-scale experimental equipment as the object,we calculated the NH3 conversion rates of different models by CFD sim-ulation,and compared with the experimental data.The model proposed in this paper had the best fit with the experi-mental values.On the basis of our kinetic model,we designed a chamber of urea thermal decomposition for an industri-al kiln furnace combined with CFD optimization.By comparing with the test of industrial installations,the correctness of the kinetic model obtained in this paper is verified to provide theoretical guidance for the development and design of urea pyrolysis equipment.
万方数据
维普
