900MW超临界塔式锅炉的技术特点

介绍了外高桥电厂二期900MW超临界塔式锅炉的基本情况。锅炉采用水平布置的对流受热面及螺旋水冷壁，能减少水冷壁的面积且受热均匀，可进行过热器及再热器的酸洗甚至取消冲管，有利于解决固体颗粒侵蚀（SPE）问题，对流受热面传热均匀且具有较高的传热利用系数和材料安全裕度，具有相当低的对流受热面磨损率和较低的烟风系统阻力，尤其是辐射（蒸发）和对流受热面比例的任意性，特别有利于高效超临界技术的发展。锅炉采用燃烧器分组，双一次风喷嘴和设置偏置风和燃尽风等技术，降低了燃烧中心温度峰值和NOX的生成，在降低燃烧区域热负荷的同时却提高了整个辐射受热面的平均热负荷，降低了水冷壁及炉膛出口的结焦风险。

A 900 MW Supercritical Tower Boiler's Technical Characteristics

The main notable points of the Waigaoqiao Power Plant's second construction stage's 900 MW supercritical boiler is being described.The horizontal layout of the boiler's convection heating surface and the spirally shaped water wall reduces the required water wall area and helps to promote the latter's heat transfer,makes acid cleaning of the super heater and reheater possible,and steam flushing may even be dispensed with,is advantageous for solving the solid particlke erosion problem,evens the heat transfer distribution over the convection heat delivery surface,with a higher heat utilization coefficient and a larger margin of safety of the material.The erosion rate of the convection heat delivery surface is lower,as well as the flow resistance of the air feeding and flue gas system.Especially no limit is set to the ratio of radiation to convection heat delivery surface,whsich is advantageous to the further development of high efficient supercritical technology.The boiler's group arranged burners,the dual primary air nozzles,the segregated dense and sparse zone,the apportionment of offset air and burn out air,all help to lower the temperature at the center of combustion and the formation of NO_X,as well as,simultaneously with lowering the thermal load in the combustison zone,raises the mean termal load of the radiation heat delivery surface and lower,the risk of coking of the water wall and the furnace's outlet.Figs 6 and refs 14.