空冷风机U型螺栓断裂原因分析及解决

针对中国石油克拉玛依石化公司某柴油加氢改质装置空冷风机固定叶片的U型螺栓接连发生多起断裂失效事故开展研究分析,发现U型螺栓的断裂主要是由于叶片安装时U型螺栓预紧力不足使其长期在松弛状态下运行造成疲劳断裂。而U型螺栓内部也存在较高的应力区域、风机叶片共振等外部因素则加速了其断裂。通过采取将风机U型螺栓更换为夹板式固定螺栓、其余型号风机将叶片轴一阶定位改造为二阶双向定位、严格规范叶片安装角度及螺栓预紧力等一系列改造措施后,空冷风机U型螺栓断裂问题得到有效解决。改造后的空冷风机已安全平稳运行14 000 h,消除了空冷机组运行中的重大安全隐患,取得了较好的改造效果。

Cause analysis of U bolt fracture in air cooler and solution

The analysis of the fracture failures of U type bolt of the air blower's fixed blade in the diesel hydro-upgrading unit has found that that the fracture of U type bolt is mainly caused by the fatigue fracture due to the relaxation state because of insufficient pretightening force of U type boly.The internal of U type bolt has a high stress area,and the resonance of fan blade and other external factors have accelerated the fracture process.The taking of effective measures has effectively solved the problem of U type bolt fracture such as replacing U type bolt with the splint fixed bolt,revamping other types of blower into two order bidirectional positioning from one leaf shaft positioning order and strictly regulating the blade installation angle and pre-tightening force,etc.After revamping,the air blowers have been operating safely and smoothly for more than 14,000 hours without any safety problems.Good results have been achieved.