Effect of Organic Chloride Contamination of Crude Oil on Refinery Corrosion

Abstract A series of sudden tube leaks in four first-stage overhead exchangers of a crude tower of a major Gulf Coast refinery was attributed to repeated contamination of the crude charge with organic chlorides. Corrosion in these exchangers increased to the point where the remaining life of the exchangers was used up in a matter of weeks. The contaminated crude oils were traced back to a single supplier that had dumped organic-chloride containing hydrocarbon waste streams into one of the refinery's pipelines over a period of 10 months, and possibly longer. The organic chloride content of the contaminated crude oils was found to have ranged from approximately 3 to 3,000 ppm (mg/L). Organic chlorides in crude oil are known to cause severe corrosion in crude tower overhead systems. Therefore, most refineries allow no more than 1 ppm (mg/L) organic chlorides in the crude charge. In this particular case, the actual crude charge contained at least 50 ppm (mg/L) at the time when most leaks occurred, and possibly as much as 255 ppm (mg/L).