Abstract:

The traceability analysis of the cracking of quench pipeline in second-stage reactor of pyrolysis gasoline hydrogenation caused by chemical corrosion and stress corrosion was carried out. Through the macroscopic and low-magnification metallographic examination of the 1# outer tube, the chemical composition analysis of the sample tube, the microstructure analysis of the sample tube, the electron microscope observation and the energy spectrum analysis, the reasons for the cracking of quench pipeline were comprehensively analyzed. It was determined that chloride ion stress corrosion cracking played a leading role, and the sensitization of welds and heat-affected zone accelerated the cracking process. Corresponding countermeasures were taken to effectively prevent the cracking of pipelines, which provides a guarantee for the long-term, safe and stable operation of pyrolysis gasoline hydrogenation unit.

Key words:  , pyrolysis gasoline, second-stage reactor, quench pipeline, cracking analysis