平圩发电厂2号锅炉再热器的超温原因及改进措施

安微淮南平圩发电有限责任公司的2号锅炉是引进美国CE公司技术,由哈锅厂制造的我国首批600MW亚临界燃煤锅炉,自投运以来,再热器多次发生因过热而超温爆管的现象。经过试验和计算分析,发现该型锅炉有因四角切圆残余旋转造成的沿宽度方向上的各片屏的热偏差,同屏之间有因吸热不均匀造成同屏各管之间的热偏差,有因结构原因造成的各管热偏差的叠加。经过分析计算,对该炉通过中上层二次风反切,过燃风水平摆动以减弱残余旋转,屏式再热器采取短路以调整各管吸热量为基本方法,制定了攻关方案,目前正在实施中。该方案在同类型锅炉上已经得到应用,取得了良好的效果。图11表3

Causes of Reheater Overheating of Pingwei Power Plant's Boiler No .2 and Remedial Measures

No.2 boiler of Pingwei Power Co. Ltd., located in Huainan, Anhui Province, is one of the first batch of 600MW subcritical coal fired boilers in China, manufactured by Harbine Boiler Works with technology licensed from CE Inc. U.S.A. After having been put into operation, it happened a couple of times that reheater tubes exploded due to overheating. It was found by tests and calculation analysis that in this type of boiler, thermal deviations exist among panels along boiler width, caused by residual whirling of tangential firing, and also among different tubes of the same panel,due to the uneven heat absorption, while some more thermal deviations are caused by structural factors. Guided by analysis and calculation, a scheme to tackle key problems was worked out with the following basic countermeasures: changing the rotational direction of secondary air in upper and middle layers, horizontally swaying the overfire air to weaken residual whirling and adjustment of heat absorption among the tubes by short-circuiting some of the platen reheater tubes. This scheme, which is now being executed, has already been applied with good results to some boilers of the same type. Figs 11and tables 3.