【摘要】 针对存在汽温偏差的某660 MW四角切圆锅炉,采用数值模拟与试验方法研究了墙式燃尽风水平摆角以及风量偏置对烟温偏差及燃烧特性的影响。模拟结果与现场实际情况吻合较好。模拟结果表明,左右墙燃尽风均等垂直送入炉内时,左侧烟气温度高于右侧,存在明显烟温偏差,现场实际运行中也表明存在明显汽温偏差。燃尽风顺时针与主气流反切送入炉内减弱了烟气残余旋转,有利于减少左右侧烟温及汽温偏差、提高燃烧效率。增加左墙燃尽风风量、减少右墙燃尽风风量后,左右侧区域烟气流量均匀性得到改善,烟温及汽温偏差减小;下炉膛未燃尽碳、CO与燃尽风混合强度增强,其燃烧剧烈程度增加,提高了燃烧效率。在实际运行中,建议燃尽风与主气流反切送入炉内,或者适当增加左墙燃尽风开度,既可以降低烟温/汽温偏差,又可以提高燃烧经济性。更多还原

【Abstract】 For a 660 MW tangential fired boiler with steam temperature deviation,this paper uses the method ofnumerical simulation and test to make studies on the influence of wall-type over fire air(OFA)horizontal angle andair volume offset on fume gas temperature deviation and combustion characteristics.The simulated results are in goodagreement with the actual situation. The simulated results are shown as follows:When the left and right OFA areevenly and vertically fed into the furnace,the fume gas temperature on the left side is higher than that on the rightside,and the actual operation on site also shows that there is an obvious deviation of the steam temperature.The OFAis fed into the furnace clockwise and tangentially with the main flow,which weakens the residual rotation of the fumegas,conducive to reducing the deviation of the fume gas temperature and steam temperature on the left and rightsides,and improving the combustion efficiency.By increasing the OFA volume on the left wall and reducing the OFAvolume on the right wall,the uniformity of the fume gas flow on the left and right sides is improved,and the deviation of the fume gas temperature and steam temperature isreduced.The mixing intensity of unburned carbon,COand OFA in the lower furnace increases,and theintensity of combustion also increases,which improvesthe combustion efficiency. Finally,the paper putsforward suggestions that in actual operation,the OFAshould be fed into the furnace in reverse tangent with the main air flow,or the opening of the OFA on the left wall should be appropriately increased,which can not onlyreduce the deviation of fume gas temperature/steam temperature,but also improve the combustion economy.更多还原