320MW机组宽负荷SCR脱硝技术的研究与应用

Research and application of wide load SCR denitration technology in a 320MW unit

为了提高锅炉机组低负荷工况脱硝反应器入口的烟气温度及改善SCR脱硝性能,提出在省煤器出口两侧加装烟气调节挡板以及增设省煤器烟气旁路的解决方案,对2种方案进行详细的技术比较分析,并在一台320 MW燃煤锅炉机组省煤器出口两侧实施了加装烟气调节挡板的改造。现场试验测试表明,锅炉省煤器出口烟气调节挡板可有效地调节低负荷时通过省煤器的烟气流量,可在35%~100%BMCR负荷区间使脱硝反应器入口烟温控制在305~410℃,有效解决了锅炉低负荷工况下因烟气温度较低引起的脱硝效率下降的技术难题。

In order to increase the flue gas temperature at the inlet of denitrification reactor and improve SCR denitration performance,two methods are proposed.In one case,a regulating damper is installed at both sides of the economizer.In the other case,a flue gas bypass is installed of the economizer.The technic comparison and analysis is included for those two schemes.Further,a regulating damper is installed in a 320 MW coal-fired boiler unit economizer to adjust the flue gas under low loads.It is observed that the flue gas temperature is 305～410℃ at the inlet of denitrification reactor when the load interval is 35%~100% BMCR.In the circumstance,the denitrification efficiency-decreasing problem caused by low flue gas temperature is technically and effectively solved on the condition of the low load.