基于流场不均匀度对SCR效率影响的探究

发布时间：2018-05-09 12:08

本文选题：SCR + 相对标准偏差系数　；参考：《热能动力工程》2016年10期

【摘要】：利用Fluent数值模拟软件对某600 MW燃煤电站锅炉的SCR(选择性催化还原法)脱硝系统进行数值模拟,研究了不同工况下SCR管道内部的流场和浓度场变化情况。引入相对标准偏差系数来衡量第一层催化剂入口处烟气浓度、速度以及温度的不均匀度,并重点分析了不均匀度随工况的变化趋势。研究表明:低负荷下烟气中的NO、NH_3浓度的不均匀度以及烟气温度的不均匀度高于其他工况,在50THA、75THA、THA、BRL、BMCR负荷下NO浓度、NH_3浓度和烟气温度的不均匀度逐渐降低。在50THA和BMCR负荷下,NO浓度不均匀度分别为0.399 131 436%、0.271 308 784%;NH_3浓度的不均匀度分别为11.431 272 594%、11.294 855 634%;烟气温度的不均匀度分别为0.081 935 553%、0.079 103 890%,NO和NH_3浓度变化趋势的吻合程度会下降。其原因是:低负荷下流场不均匀度升高导致SCR脱硝效率降低,可以通过有针对性地优化锅炉运行、SCR脱硝系统的设计等来减缓催化剂的失活速率。
[Abstract]:The Fluent numerical simulation software was used to simulate the denitrification system of a 600MW coal-fired utility boiler. The flow field and concentration field in the SCR pipeline under different working conditions were studied. The relative standard deviation coefficient is introduced to measure the unevenness of flue gas concentration, velocity and temperature at the entrance of the first layer catalyst. The results show that the inhomogeneity of NON-NH3 concentration and flue gas temperature in the flue gas under low load is higher than that in other working conditions, and the concentration of no NH3 and the unevenness of flue gas temperature decrease gradually under the load of 50THA75 THAA and BRL BMCR. Under the loading of 50THA and BMCR, the inhomogeneity of no concentration was 0.399 131 436 6 and 0.308 78 4 4, respectively. The inhomogeneity of NH 3 concentration was 11.431 272 594 and 11.294 855 634, respectively, and the uniformity of flue gas temperature was 0.081 935 553 3 0 079 103 890 0 0 0. The degree of consistency between no and NH_3 concentration would decrease. The reason is that the SCR denitrification efficiency is decreased due to the increase of flow field unevenness under low load, and the deactivation rate of the catalyst can be slowed down by optimizing the design of the boiler running SCR denitrification system and so on.
【作者单位】：中北大学机械与动力工程学院;山西平朔煤矸石发电有限责任公司;
【基金】：国家基金委介观尺度下热对流对颗粒两相流动影响的eDPD研究(51476150)
【分类号】：X773

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