摘要
以某660 MW燃煤锅炉SCR脱硝系统为对象,建立了电站实际烟气环境下的催化剂磨损评估模型.首先,利用计算流体力学软件(CFD)搭建SCR反应器模型,计算反应器内气流分布及飞灰颗粒轨迹.在此基础上,采用MATLAB软件构建催化剂床层内部详细结构,并以CFD模型计算的流场及灰场为边界条件,计算空间不同区域催化剂的磨损速率.模拟结果与冷态试验及磨损抽检试验结果吻合良好.结果表明,催化剂的磨损与入口流场均呈现双峰分布,割除整流器上方三角筋能使催化剂入口速度标准偏差从23. 2%下降至10. 2%,使磨损双峰大幅降低;改造转角烟道导流板能降低贴墙气流的速度,提高颗粒分散度,使催化剂入口飞灰浓度的标准偏差从63. 4%降至55. 6%,消除了前墙附近催化剂磨损过重的现象.
A selective catalytic reduction (SCR) system in 660 MW coal-fired boiler was taken as an example, and a erosion model was developed for the SCR catalysts in actual gas environment of the power plant. First, a three-dimensional computational fluid dynamics (CFD) model for the SCR reactor was established to obtain the distribution of flue gas and ash particles. Then, the detailed structures of the inner catalyst layer were simulated by MATLAB program. According to the boundary conditions obtained from CFD models, the erosion rates in the different regions were calculated. The simulation results were in good agreements with that of the cold state test and erosion measurements. The result indicates that the erosion rate and the velocity in front of the catalyst layer are both bimodal distribution, the removal of the the triangular beams can reduce the deviation of gas velocity from 23.2% to 10.2% and play a major role in decreasing the erosion degree in the bimodal region. Furthermore, after retrofitting the turning vanes, the gas velocity closed to the wall decreases, and the ash particles disperse well, reducing the deviation of ash concentration from 63.4% to 55.6% and eliminating the heavy erosion near the front wall.
作者
喻聪
司风琪
董云山
江晓明
Yu Cong;Si Fengqi;Dong Yunshan;Jiang Xiaoming(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, China;Datang Nanjing Environmental Protection Technology Co., Ltd., Nanjing 211100, China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第1期133-140,共8页
Journal of Southeast University：Natural Science Edition
关键词
燃煤锅炉
SCR系统
气固两相流
催化剂磨损
混合数值模拟
coal-fired boiler
selective catalytic reduction (SCR) system
gas-solid flow
catalyst erosion
hybrid simulation
