Abstract:

The condenser in propylene rectification tower of ethylene plant is used to condense the gas-phase propylene from the top of propylene rectification tower. Corrosion leakage of tube bundle occurred during its operation. During an overhaul in 2019，the causes of the tube bundle leakage of condenser in propylene rectification tower were found out by macroscopic examination of heat exchanger, cooling water analysis and chemical analysis of corrosion fouling. The analysis results showed that the under-deposit corrosion due to the slime biological fouling at tube side circulating water end is the main cause of the tube bundle leakage of condenser, the shell side process medium is less corrosive, the microbial corrosion and oxygen corrosion in circulating water, the stress relaxation at expansion of tube bundle and tube plate at high temperature and the crevice corrosion at the weld between tube bundle and tube plate also play a certain role in promoting the tube bundle leakage, so corrosion leakage occurred in the tube bundle of condenser under the combined action of these five corrosion forms. Some protection measures such as regular backwashing of condenser, key indicator monitoring of circulating water and anticorrosive coating for condenser tube side were put forward to guarantee the long period, safe and stable operation of the plant.

Key words: propylene condenser, leakage, corrosion