提高SCR反应效率的烟气温度优化调整技术研究

发布时间：2018-05-29 00:46

  本文选题：SCR催化剂 + 反应效率　； 参考：《浙江大学》2014年硕士论文

【摘要】：国内燃煤电站实际应用SCR(选择性催化还原)烟气脱硝技术过程中,经常出现中、低负荷下SCR反应器入口烟温低于SCR催化剂的最佳反应温度窗口,严重时甚至低于正常反应温度等问题,导致SCR反应器运行效率明显偏低,严重影响锅炉的脱硝效率、NOx排放浓度和氨逃逸率,同时氨逃逸率增加还会引起空预器的堵灰问题。因此,需要在不影响锅炉整体运行下,有效提高SCR反应效率,维持SCR催化剂的较高活性,保证原SCR反应器系统高效稳定运行的同时,解决空预器堵灰隐患。 本文以某重点地区燃煤电站300MW机组作为研究对象,从工程应用角度出发,寻求开发提高SCR反应效率的烟温优化调整技术。 本文首先提出了四种不同烟温调整方案,并最终优化选择了高温烟气旁路方案作为烟温控制方案,其旁路烟气份额最大为20%；同时,创新性地提出了SCR省煤器,用于解决高温烟气旁路带来的排烟温度升高的不利影响,并通过热力计算确定了SCR省煤器面积(原省煤器面积的40%)。 对高温烟气旁路与SCR省煤器联合布置方案进行了详细的模拟计算,结果表明,在最低烟温工况下,SCR入口烟温可调节达到接近340℃,排烟温度略有增加；在最高烟温工况下,SCR入口烟温不需调节,排烟温度可降低6.1℃。 高温烟气旁路与SCR省煤器联合布置烟温协调优化方案基本实现了全运行工况下SCR入口烟温在340℃以上的催化剂高效运行需求,排烟温度在更小、更优化的范围内变化。总体上排烟温度呈下降趋势,锅炉负荷越高排烟温度下降幅度越大,假设全年平均负荷为75%,则近似平均排烟温度下降5.2℃,发电煤耗降低接近1g/kWh。
[Abstract]:In the practical application of SCR (selective Catalytic reduction) flue gas denitrification in coal-fired power plants in China, the inlet smoke temperature of SCR reactor under low load is often lower than the optimal reaction temperature window of SCR catalyst. The operation efficiency of SCR reactor is obviously low when it is serious or even lower than normal reaction temperature, which seriously affects the NOx emission concentration and ammonia escape rate of boiler. At the same time, the increase of ammonia escape rate will also cause the ash plugging problem of air preheater. Therefore, it is necessary to effectively improve the efficiency of SCR reaction, maintain the higher activity of SCR catalyst, and ensure the efficient and stable operation of the original SCR reactor system without affecting the overall operation of the boiler, and at the same time solve the hidden danger of ash plugging in the air preheater. In this paper, the 300MW unit of a coal-fired power station in a key area is taken as the research object. From the point of view of engineering application, this paper seeks to develop the optimization adjustment technology of gas temperature to improve the efficiency of SCR reaction. In this paper, four different kinds of smoke temperature adjustment schemes are put forward, and the high temperature flue gas bypass scheme is selected as the smoke temperature control scheme, and the maximum bypass flue gas share is 20. At the same time, the SCR economizer is innovatively proposed. It is used to solve the adverse effect of high temperature flue gas bypass on the rise of exhaust gas temperature, and the area of SCR economizer (40% of the original economizer area) is determined by thermodynamic calculation. The detailed simulation calculation of the arrangement scheme of high temperature flue gas bypass and SCR economizer is carried out. The results show that under the lowest smoke temperature condition, the inlet smoke temperature can be adjusted to nearly 340 鈩，

本文编号：1948841