催化烟气轮机叶片断裂失效分析及预防措施

发布时间：2018-09-03 07:16

【摘要】：烟气轮机是石化企业催化装置回收再生烟气能量的重要设施,其运行正常与否对催化装置的安全和效益有着十分重要的影响,本论文对催化装置烟气轮机叶片断裂失效的原因进行分析,并提出改进措施,防止断裂事故重复发生,对保障装置的安稳长满优运行具有十分重要意义。高桥石化公司3#催化装置烟气轮机于1998年7月投用,2013年4月烟机的主风机组突然停机,机组解体检查发现烟机的一片动叶断裂,导致烟机由于严重动不平衡而振动超标联锁停机。本文选取断裂叶片进行宏观检查、理化检验、力学性能测试、断口分析、腐蚀产物分析等,并对动叶片进行应力计算及疲劳寿命分析,从而得出叶片断裂的原因。从改善烟机运行环境和提高叶片自身性能方面提出了相应的改进措施,在实际应用中取得了良好使用效果。主要得到结论如下：烟机叶片断裂模式属于疲劳断裂,叶片高应力区表面的凹坑正是疲劳裂纹萌生的起源。高温硫腐蚀和催化剂颗粒的冲蚀共同造成了点蚀坑应力集中源的出现,加上长期高温运行引起的晶界弱化对叶片断裂起了促进作用。断裂的国产叶片与进口叶片相比,硬度较低、材料化学成分控制相对不严格、高温力学性能较差,所有这些因素使国产叶片更容易发生断裂事故。再生器内催化剂烧焦产生的SOx有时浓度较高,对烟机叶片的GH864合金造成了低温热腐蚀；高温烟气中大于5μ m催化剂微粒产生的冲蚀作用,这是烟机叶片产生疲劳裂纹源的的外在因素。在防止动叶片突然断裂的改进措施研究中,通过设置预提升段和采用新型高效雾化喷嘴等措施以降低生焦率；改进蜡油加氢装置精制效果以提高催化原料脱硫脱氮率,最终降低烟气中SOx含量。在运行管理上控制原料杂质含量,加强催化剂使用管理等措施减轻催化剂颗粒的冲蚀。最后采用喷涂Cr3C2/NiCr金属陶瓷的方法来构筑叶片防护的最后一道屏障。改进措施应用后的实际效果表明,烟机叶片断裂产生的原因分析是正确的,采取的改进措施是有效的,取得了预期的效果。
[Abstract]:Flue gas turbine is an important facility for recovering regenerated flue gas energy from catalytic units in petrochemical enterprises, and its normal operation has a very important effect on the safety and efficiency of the catalytic units. In this paper, the causes of fracture failure of flue gas turbine blades in catalytic unit are analyzed, and the improvement measures are put forward to prevent the recurrence of fracture accidents, which is of great significance to ensure the stable and stable operation of the equipment. The flue gas turbine of Gaoqiao Petrochemical Co., Ltd. was put into use in July 1998. In April 2013, the main wind turbine of the cigarette machine stopped suddenly, and the unit disintegrated and checked that a moving blade of the cigarette machine was broken. Lead to the smoke machine due to serious dynamic imbalance and vibration over the standard interlocking stop. In this paper, the fracture blade is selected for macroscopic inspection, physical and chemical examination, mechanical property test, fracture analysis, corrosion product analysis, and the stress calculation and fatigue life analysis of the moving blade are carried out to obtain the cause of the blade fracture. From the aspects of improving the running environment of the tobacco machine and improving the performance of the blade, the corresponding improvement measures are put forward, and good results are obtained in the practical application. The main conclusions are as follows: the fracture mode of tobacco blade belongs to fatigue fracture and the crater on the surface of the blade in high stress zone is the origin of fatigue crack initiation. The high temperature sulfur corrosion and the erosion of catalyst particles caused the occurrence of stress concentration source in the pitting pit, and the grain boundary weakening caused by the long-term high temperature operation promoted the blade fracture. Compared with the imported leaves, the broken domestic leaves have lower hardness, less strict control of the chemical composition of the materials, and poor mechanical properties at high temperature. All these factors make the domestic leaves more prone to fracture accidents. The concentration of SOx produced by catalyst burning in regenerator is sometimes high, which results in low temperature hot corrosion of GH864 alloy of tobacco blade, erosion effect of catalyst particles larger than 5 渭 m in high temperature flue gas. This is the external factor of fatigue crack source of tobacco blade. In the study of improving measures to prevent sudden breakage of moving blade, by setting pre-lifting section and adopting new high-efficiency atomizing nozzle to reduce coking rate, improving the refining effect of waxy oil hydrotreating unit to increase desulfurization and denitrification rate of catalytic feedstock, Finally, the content of SOx in flue gas was reduced. In operation management, the impurity content of raw material is controlled, and the operation management of catalyst is strengthened to reduce the erosion of catalyst particles. Finally, the last barrier of blade protection was constructed by spraying Cr3C2/NiCr cermet. The actual effect of the application of the improved measures shows that the analysis of the causes of the blade breakage is correct and the improvement measures taken are effective and the expected results have been obtained.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96

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