Fouling and related corrosion problems in crude distillation and naphtha hydrotreating units are often the symptoms of more fundamental problems. Some of these underlying problems are: the varying quality of the incoming crude, operating upsets in the desalters, inadequate procedures for draining the storage tanks, and the inappropriate use of process chemicals. The consequences of these problems can be higher corrosion rates, heat exchanger fouling, effluent water problems, increased energy consumption, and deactivation of catalysts in residue processing units. This paper describes a systematic approach to
identifying the root causes and the solutions of corrosion and fouling in the crude distillation unit overhead and hydrotreater reactor effluent systems. This method has proven its effectiveness and efficiency to resolve complex and often puzzling problems, by combining multiple resources and skills needed to identify the cause of the problem and implement the solutions. Examples of recent case histories from several refineries illustrate the method.
Keywords: CDU, hydrotreater, corrosion, fouling, desalting, pH, chloride, neutralization, amines, ammonia, ammonium chloride, amine
hydrochloride, process additives, sour water