一种新型喷氨嘴布置优化设计方法

Optimal Design of the Ammonia Nozzle Distribution for SCR-deNOx Facilities

我国SCR脱硝技术仅有25年应用历史,在对原有火电机组进行SCR脱硝工程改造时,存在因空间受限导致的还原剂混合距离过短,有时没有空间安装用于保证催化剂入口氨浓度分布一致性的混合格栅,导致氨逃逸浓度和脱硝效率难以达到设计指标。针对这些问题,提出了一种适用于空间受限烟气脱硝装置的新型喷氨嘴布置优化设计方法。具体地,采用计算流体力学仿真软件ANSYS 17.1,对某150 MW机组半π式脱硝装置的氨浓度分布场进行数值模拟,寻优喷氨嘴位置与喷氨方向,使催化剂入口氨浓度的相对标准差满足预设标准。

Flue gas SCR denitrification has been applied for only 25 years in China.Therefore,while applying SCR denitrification facility for old plants,the flue gas-ammonia mixing distance is usually too short to install hybrid grid,which is used to guarantee the uniformity of the ammonia concentration distribution at the entrance of the catalyst layer.As a result,denitrification efficiency and ammonia escape concentration are hard to reach the design criterion.To solve this problem,this paper proposes an optimal design method of ammonia nozzle distribution for SCR-deNOx facilities under space limitation.Concretely,CFD software ANSYS17.1 was applied to do numerical simulation of ammonia concentration field for a half-πtype SCR-deNOx facility.With this method,the installing location and direction of ammonia nozzles are optimized and the RSD(relative standard deviation)of the ammonia concentration distribution meet the prespecified criterion.