加氢裂化装置脱丁烷塔顶换热器失效原因分析及预防措施

Failure Analysis and Preventive Measures of Top Heat Exchanger of Debutanizer in Hydrocracking Unit

脱丁烷塔顶换热器是加氢裂化装置中关键设备之一,一旦发生失效,会导致装置的非计划停车。本文通过宏观检验、介质成分分析、表面缺陷检测和埋藏缺陷检测等方法,对脱丁烷塔顶换热器失效原因进行了分析。在含有水、硫化氢和氨等腐蚀性介质环境中,碱式酸性水腐蚀、冲刷以及湿硫化氢环境下的氢致开裂(HIC)是导致换热器腐蚀和开裂的主要原因。针对失效原因,从防腐、设计、制造、选材等方面给出了预防措施及建议,对预防加氢裂化装置脱丁烷塔顶换热器失效具有一定的指导意义。

Debutanizer top heat exchanger is one of the key equipment in hydrocracking unit.Once it fails,it will lead to unplanned shutdown of the unit.In this paper,the failure reasons of the top heat exchanger of debutanizer are analyzed by means of macroscopic inspection,medium composition analysis,surface defect detection and buried defect detection.In the corrosive medium environment including water,hydrogen sulfide and ammonia,the main causes of corrosion and cracking of heat exchanger are corrosion of basic acid water,erosion and hydrogen induced cracking in wet H2S environment.In view of the failure reasons,the preventive measures and suggestions are given from the aspects of corrosion prevention,design,manufacture and material selection,which have certain guiding significance for preventing the failure of the top heat exchanger of the debutanizer in the hydrocracking unit.