Analysis and Optimization on Fracture Causes of Pre-riser in Catalytic Cracking
The frequent failure of the prelift pipe in a heavy oil catalytic cracking unit was deeply studied,and refined detection and analysis were carried out.The results show that the main reasons for the failure of the pre-lift pipe are corrosive cracking of high tem-perature hydrogen sulfide gas,continuous erosion under high temperature environment and fatigue stress under alternating load.In ad-dition,it was found that carbonization occurred in the pipe under high temperature conditions.In view of the above problems,an opti-mization and improvement scheme is proposed to fundamentally eliminate the corrosion effect of high temperature hydrogen sulfide and effectively avoid fatigue damage caused by alternating load.The operation results show that the normal service life of the pre-lift tube is significantly extended.At the same time,the radial distribution of the catalyst in the lifting tube has been optimized,achieving more uniform and sufficient contact between the catalyst and the raw material.
pre-lift tubecorrosion crackingfatigue failureerosion wearhigh temperature carbonization
万方数据
维普
