Physicochemical basics of corrosion at refineriesʼ units

Abstract

Physicochemical mechanisms of metal corrosion at refineriesʼ units are described. Low- (T < 100 °C) and high- (T > 200 °C) temperature corrosion problems are analyzed. Corrosion by hydrochloric acid and its prevention, electrochemical mechanism of corrosion in acid, neutral and alkali aqueous solutions of electrolytes are explained. Main factors affecting corrosion rate and its intensity are temperature, pressure, flow regime, and media. The following chemical compounds and mixtures are analyzed from corrosiveness: water, air, hydrogen sulfide, substances containing nitrogen, phenols, polythionic acids, organochlorine and organic chloride compounds, aluminum chloride, sulfuric acid, and alkaline solutions (sodium hydroxide, sodium carbonate, ammonium hydroxide, amines, sour water, and spent caustic).