SCR烟气脱硝系统的数值模拟与优化设计

Numerical Simulation and Optimization Design of SCR Flue Gas Denitrification System

针对SCR烟气脱硝系统,采用数值模拟的方法研究了初始设计方案和优化设计方案的流场特性。模拟结果表明:初始设计方案中喷氨上游截面和首层催化剂入口截面的速度分布相对偏差较大,催化剂层的氨氮比分布不均匀;通过加装合适的烟气导流装置可以明显改善喷氨上游截面和首层催化剂入口截面的速度分布,同时也能降低氨氮比的不均匀程度;优化设计方案中各截面的速度相对偏差和氨氮比的均匀性都已满足工程实际的要求,有利于烟气中NOx的脱除。

Numerical simulation was carried out to investigate the filed flow characteristics of the SCR flue gas denitrification. In the initial design scheme,the velocity distribution had a large deviation in the upstream of ammonia injection grid（ AIG）,and the inlet of first catalyst layer and the ratio of ammonia to nitrogen in the catalyst layer was not uniform. By installing a suitable flue gas diversion device,the velocity distribution in the upstream of AIG and in the inlet of first catalyst layer can be obviously improved,and the unevenness of the ammonia nitrogen ratio can also be reduced. For the optimization design scheme,the relative velocity deviation and the ammonia nitrogen ratio in each design section has met the requirements of engineering practice,and it is beneficial to remove NOxin flue gas.