SCR进口烟道飞灰拦截与均匀布置技术应用研究

Research and Application of Interception and Uniform Distribution Technology of Fly Ash in SCR Inlet Flue Gas Duct

针对燃煤电厂选择性催化还原(SCR)烟气脱硝装置普遍出现的靠近前墙几排催化剂严重积灰堵塞问题,以某350 MW燃煤机组为例,采用计算流体力学(CFD)数值模拟和现场测试进行了分析诊断,并采用飞灰拦截与均匀布置进行了催化剂防堵改造。研究表明:粗颗粒灰偏流是造成顶层催化剂上游靠近前墙区域的飞灰浓度偏高,催化剂积灰堵塞严重的根本原因。采用省煤器出口大颗粒拦截与上升烟道飞灰扩散均匀布置方案改造后,顶层催化剂严重积灰问题得到了有效解决。

The serious fouling and blocking problems of several rows at first layer catalysts near the front wall were investigated in this paper,which are common in the selective catalytic reduction(SCR)de-NO_(x) device of coal-fired boilers.Taking a 350 MW coal-fired unit as an example,CFD numerical simulation and field test were used to carry out diagnostic analysis,and the catalyst anti blocking modification was carried out using fly ash interception and uniform layout.Studies have shown that bias flow of coarse ash leads to a significantly higher fly ash concentration in the area near the front wall upstream of the top catalyst,and the accumulation of coarse fly ash in this area aggravates the wear of the catalyst.After adopting the plan of intercepting large particles at the economizer outlet and evenly distributing fly ash in the ascending flue gas duct,the serious fouling and blocking problems at several rows of top layer catalysts has been solved effectively.