600MW超临界循环流化床锅炉水冷壁热应力分析

Thermal Stress Analysis of Water Wall in a 600MW Supercritical CFB Boiler

为研究超临界循环流化床锅炉水冷壁的变形问题,在实炉测量某600 MW超临界循环流化床锅炉炉膛水冷壁壁温分布的基础上,采用数值模拟方法对距离布风板30m高度处4.6m×2m区域的水冷壁管进行了热应力分析。结果表明:80%负荷工况下,距离布风板30m高度处区域的水冷壁管沿炉膛高度方向的温度变化率较大,热应力分布极不均匀;计算区域的水冷壁管整体向下膨胀,由于存在膨胀偏差,水冷壁向火侧向炉内凸起变形,最大变形量约1.14mm;对于整个水冷壁管屏而言,存在的变形量叠加会加剧水冷壁磨损,甚至造成爆管事故。

To investigate the deformation of water wall in a supercritical circulating fluidized bed（CFB）boiler,based on the experimental data of water wall temperature distribution in a 600 MW supercritical CFB boiler,numerical simulation was carried out on the thermal stress of water wall with an area of4.6 m×2 mat the height of 30 mabove the air distributor.Results show that at 80%load,the temperature of water wall in the calculated area changes greatly along the height direction,and the distribution of thermal stress is extremely uneven.The water wall tube in the calculated area expands to the bottom of the boiler.Due to the deviation of expansion,the maximum protuberant deformation of the water wall to the center of the boiler is about 1.14 mm.For the whole water wall,the deformation may be superimposed,which can aggravate the abrasion of water wall and even cause the break of water wall tubes.