Corrosion of copper metal in distillation process

Corrosion in atmospheric distillation is caused by hydrochloric acid produced by the hydrolysis of water soluble magnesium and calcium chlorides found in the crude oil. Corrosion of copper metal during distillation of Geisum crude oil (vapour phase ) at 100, 150, 200, 250, and 300°C in absence and presence of 5 per cent H₂O was studied. The corrosion of copper metal in the vapour phase is higher than in the liquid phase. Hydrogen sulphide is not the only corrodant present; hydrogen chloride and volatile acids are other important corrodants. The effect of adding different inhibitors with various concentrations on the corrosion of copper metal was also studied. The rate of inhibition increases with addition of chlorinated hexadecylamine as compared with that obtained by addition of ammonia alone. The inhibitive efficiency of copper increased rapidly as the copper benzotriazole film grows rapidly.