SCR脱硝尿素热解制氨反应动力学研究  

Reaction Kinetics of Ammonia Production by Urea Thermal Decomposition by SCR Denitration

作　　者：岳朴杰 孟磊 高攀[2] YUE Pujie;MENG Lei;GAO Pan(Datang Environment Industry Group Co.,Ltd.,Beijing 100097,China;School of New Energy,North China Electric Power University,Beijing 102206,China)

机构地区：[1]大唐环境产业集团股份有限公司,北京100097 [2]华北电力大学新能源学院,北京102206

出　　处：《华北电力大学学报（自然科学版）》2024年第6期130-138,共9页Journal of North China Electric Power University：Natural Science Edition

基　　金：中央高校基本科研业务费专项资金资助项目(2018MS033);大唐环境产业集团科技研发项目(CDTHT20200115282).

摘　　要：由于缺少准确的反应动力学模型,热解炉设计时难以采用CFD进行结构优化和氨转化率预测,导致运行中频发结晶堵塞等问题,严重制约了SCR脱硝系统的安全稳定运行。采用管式反应器在300~500℃温度范围内,实验研究了尿素热解制氨反应,发现尿素热解速率和异氰酸水解速率显著依赖于反应温度和停留时间,计算了两步反应的反应速率,通过ln k和1/T的线性拟合,确定了活化能和指前因子;以文献中试实验装置为对象,采用CFD计算了不同模型的NH 3转化率并与实验值对比,所提出模型的预测值与实验值吻合良好,拟合效果优于已有模型;以模型为基础并结合CFD优化,为某工业窑炉设计了尿素热解炉,通过与现场测试数据对比,验证了动力学模型的正确性,可为尿素热解制氨设备的开发、设计提供理论指导。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 experimentally studied the conversion rate of CO(NH 2)2 to NH 3 and HNCO in a tubular reactor at 300~500℃and found that the thermal decomposition rate of CO(NH 2)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 ln k and 1/T.Taking the pilot-scale experimental equipment as the object,we calculated the NH 3 conversion rates of different models by CFD simulation,and compared with the experimental data.The model proposed in this paper had the best fit with the experimental values.On the basis of our kinetic model,we designed a chamber of urea thermal decomposition for an industrial 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.

关 键 词：尿素热解 异氰酸水解 氨转化率 动力学 数值模拟 

分 类 号：X701[环境科学与工程—环境工程]