Abstract: This paper introduces the tube burst of 0Cr18Ni10Ti tube bundle of a hydrocracking unit reaction effluent / low separation heat exchanger (E106A) in a refinery. Combined with the working conditions of the tube and shell side of the heat exchanger and the anti-corrosion measures, the tube burst samples are analyzed comprehensively by means of endoscopy, spectral material analysis, hardness performance analysis, metallography and scanning electron microscope analysis. The crystal was analyzed by adopting XRD and energy spectrum. The results show that there is NH₄Cl crystal in the inner wall of E106A heat exchanger tube bundle. When the amount of water injection is insufficient, the acid environment formed by hydrolysis of ammonium chloride improves the sensitivity of Cl^- stress corrosion cracking of austenitic stainless steel, which leads to transgranular stress corrosion cracking of the tube bundle of E106A heat exchanger. When the crack extends to a certain extent, the tube bursts. In view of the above corrosion cracking reasons, the corresponding anti-corrosion suggestions and measures are put forward from the aspects of process control and equipment material selection.

Key words: hydrogenation heat exchanger, stress cracking of austenitic stainless steel, salt scaling of hydrocracking unit, water injection for hydrocracking unit