Abstract: The composite evaporative air cooler in the 2.2 Mt/a deep catalytic cracking unit of a petrochemical companyhas experienced many tube bundle leaks since the first start-up of the unit. Based on the analysis of the composition of the scale on the outer wall of the air cooler tube bundles, the causes of the leakage of the air cooler tube bundles were analyzed in detail, which could be concluded asthe corrosionunder scale, crevice corrosion, and chloride ion corrosion. In response to the above reasons, measures such as strengthening water quality control, upgrading tube bundle materials, periodic corrosion detection and optimizing operating conditions could slow down the corrosion rate of air cooler tube bundles and prolong the air cooling operation cycle. In addition, formulating a reasonable monitoring operation measures and emergency response plans can effectively reduce the degree of tube bundle leakage to ensuresafe production.

Key words: deep catalytic cracking, stability tower, compound evaporative air cooler, tube bundle leakage, corrosion