Passivation of ethylene cracker transfer line heat exchangers

摘要

Diethylhydroxylamine (DEHA) has proven to be an effective oxygen scavenger for transfer line heat exchangers (TLEs) in the production of super high-pressure steam. After four years' experience using DEHA in the TLE systems of Egyptian Petrochemicals' ethylene crackers, the replacement of hydrazine with DEHA has led to both outstanding protection from oxygen corrosion and excellent feed water passivation in the TLE systems. DEHA contributes no dissolved solids or ammonia to the system, and has been shown to be a strong metal passivator in both laboratory works and plant applications. Measurements of the polarisation characteristics of mild steel in the presence of these compounds reveal enhanced passive film formation between pH ranges of 8-9.