大型火电机组SCR烟气脱硝全流场数值模拟分析与优化  

Numerical simulation and optimization for SCR flue gas denitration full flow field of large thermal power units

作　　者：刘一帆 董建宁 田煜昆 潘佩媛 陈衡[1] 徐钢[1] 欧阳朔 刘文毅[1] LIU Yifan;DONG Jianning;TIAN Yukun;PAN Peiyuan;CHEN Heng;XU Gang;OUYANG Shuo;LIU Wenyi(Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学热电生产过程污染物监测与控制北京市重点实验室,北京102206

出　　处：《热力发电》2022年第9期103-110,共8页Thermal Power Generation

基　　金：国家自然科学基金项目(52106008);国家自然科学基金创新研究群体项目(51821004)。

摘　　要：针对某1 000 MW机组选择性催化还原烟气脱硝系统内流场分布不均与氨逃逸值过大的现象,采用ANSYS Fluent软件对该系统进行数值模拟研究。通过分析原模型的流场、浓度场、氨逃逸与脱硝效率等特性,分别提出针对流场分布的三角区域扰流板布置方案和针对反应物浓度场分布的氨气入口角调整与平衡喷氨策略。研究结果表明:在三角烟道区域顶部增设5块平行扰流板可缓解烟气在壁面处速度过大的现象,催化剂入口流速相对标准偏差由16.31%下降至8.10%,有效地提高了系统的流场分布均匀性;在采用氨气入口角优化结合平衡喷氨策略后,催化剂入口氨气浓度相对标准偏差下降至20.62%,反应器出口的氨逃逸量平均值由0.120 03×10^(–3) mol/m~3下降至0.058 23×10^(–3) mol/m~3,降低了氨逃逸对后续系统的影响。The uneven flow field distribution and large ammonia escape value in selective catalytic reduction(SCR) system of a 1 000 MW unit is numerically investigated by ANSYS Fluent software.By analyzing the flow field,concentration field,ammonia escape and denitrification efficiency of the original model,a triangular area spoiler arrangement scheme for the flow field distribution,ammonia inlet angle adjustment and balanced ammonia injection strategy for the reactant concentration field distribution are proposed respectively.The results show that,the addition of five parallel spoilers at the top of the triangular flue area can reduce the excessive velocity of flue gas at the wall,and the relative standard deviation of the catalyst inlet velocity decreases from 16.31% to 8.10%,which effectively improves the uniformity of the flow field distribution of the system.After the ammonia inlet angle optimization combined with the balanced ammonia injection strategy,the relative standard deviation of the ammonia at the catalyst inlet decreases to 20.62%,the average ammonia escape at the reactor outlet reduces from 0.120 03×10^(–3) mol/m~3 to 0.058 23×10^(–3) mol/m~3,which decreases the effect of ammonia escape on the subsequent system.

关 键 词：数值模拟 氨逃逸 SCR烟气脱硝 流场优化 浓度场优化 

分 类 号：X701[环境科学与工程—环境工程]