基于流场诊断的燃煤电站SCR系统喷氨优化及试验验证

Optimization and experimental verification of AIG tuning for SCR system of coal-fired power station based on diagnose of flow field

为实现SCR系统的安全高效运行,采用CFD数值模拟技术开展660 MW燃煤电站SCR系统流场优化.根据喷氨格栅前烟气流动特性解析喷氨支管阀门权重,基于权重阀开展喷氨优化研究.分析了优化前后首层催化剂入口截面烟气速度/浓度分布特性,搭建冷态模化试验装置对数值模拟研究结果进行验证.研究结果表明:导流板合理优化布置可有效改善流场分布的均匀性,速度标准偏差可相对减少约71.30%;基于权重阀优化喷氨使喷氨特性与烟气流动特性匹配良好,改善了浓度分布的均匀性,浓度标准偏差相对减少约24.95%;冷态模化试验值与数值模拟值吻合良好,两者偏差仅为3.08%;流场/权重阀喷氨优化协同作用能够最大限度提升燃煤电站SCR系统的工作性能.

To realize the operation of SCR(selective catalytic reduction)system safely and efficiently,CFD(computational fluid dynamics)numerical simulation technique is adopted to carry out flow field optimization of SCR system process aimed at the coal-fired power station of660MW.The weight of spraying-ammonium branch pipe valve was analyzed based on the flue gas flow characteristics in front of ammonium grid,and the optimization research of AIG(ammonia injection grid)tuningwas launched based on the weight-valve.The velocity/concentration distribution characteristicsof the flue gas in the first-layer catalyst inlet cross section were analyzed before and after optimization.Meanwhile,the cold mold experiment device was built to verify the conclusion of the simulation research.Experimental results indicate that reasonable optimization of the guide plate improves the uniformity of the flow field distribution,and the relative decrease of velocity is about71.30%.AIG tuning based on weight-valve realizes the good match of spraying ammonium and flue gas flow characteristic and improves the uniformity of the concentration distribution,and the relative decrease of concentration amounts is about24.95%.Cold model experimental values are in agreement with that of numerical simulation and the deviation is only about3.08%.And the cooperation of flow field and weight-valve AIG tuning optimization contributes to a maximum advancement of the SCR system operating performance in the coal-fired power station.