省煤器烟气旁路在SCR烟气脱硝系统中的应用  

Application of economizer bypass on selective catalytic reduction system

作　　者：董陈[1] 王晓冰[1] 牛国平[1] 

机构地区：[1]西安热工研究院有限公司,陕西西安710032

出　　处：《热力发电》2014年第3期96-100,共5页Thermal Power Generation

摘　　要：由于机组低负荷运行时,选择性催化还原(SCR)烟气脱硝系统的入口烟气温度低于最低喷氨温度,会导致SCR系统无法喷氨运行。为此,需设置省煤器烟气旁路。以某火电厂600MW机组SCR系统为例,通过数值模拟的方法得到最佳省煤器烟气旁路方案,即将省煤器旁路入口设于喷氨格栅前,将部分接口伸入进口烟道内,加深高温烟气进入SCR系统水平烟道的射入距离,有利于高温烟气和低温烟气迅速混合。该方案实施后,第1层催化剂入口截面上烟气平均温度为319℃,烟气温度分布的最大偏差为2.4%,满足最低喷氨温度要求。To protect catalyst from ammonium sulfate/bisulfate deposition and subsequent poisoning, the minimum operation temperature at low load should not be violated. Therefore, the selective catalytic reduction （SCR） system should be down at low load. However,the exit NOx concentration may not meet the emission standards. The application of economizer bypass is an effective way to solve this problem. Taking the SCR system of a 600 MW coal-fired power plant as the example, the numerical simulation method was employed to obtain the optimum economizer bypass scheme. By using the optimum economizer bypass, the average flue gas temperature at inlet cross section of the first catalytic layer increases to 319 ℃ ,which is above the minimum operation temperature, and the maximum deviation of the flue gas temperature distribution in this cross section is 2.4%, which satisfies the minimum ammonia spraying temperature.

关 键 词：SCR系统 催化剂 喷氨温度 省煤器 烟气旁路 

分 类 号：X773[环境科学与工程—环境工程]