关键词: 乙烯装置, 稀释蒸汽发生器, 腐蚀泄漏, 腐蚀产物, 腐蚀介质, 工艺防腐, 汽蚀, 结焦

Abstract:

The frequent leakage of the tube bundle of dilution steam generator of ethylene plant in a petrochemical company has seriously affected the long-term and stable operation of the plant. The on-site macroscopic inspection results show that the leakage of the tube bundle is mainly concentrated in the gas-liquid phase change zone of the process water on the upper part of the shell side tube bundle, and its morphology has both corrosion grooves and “horseshoe” corrosion pits. Alkali corrosion and cavitation are the main reasons for the corrosion leakage of the dilution steam generator tube bundle, while the development of the tube bundle corrosion is promoted by such influencing factors as coking and medium design of the tube shell side. In view of the causes and influencing factors of corrosion leakage of tube bundle of dilution steam generator, the anti-corrosion control measures such as fine management of injection process, strict control of pH value of process water, introduction of toluene extraction process to control coking, and process water blowdown have been taken, and good protective effects have been achieved.

Key words: ethylene plant, dilution steam generator, corrosion leakage, corrosion products, corrosive medium, process anti-corrosion, cavitation, coking