The development of Corrosion Control Document (CCD) in refinery: Crude Distillation Unit (CDU) process

This study focuses on techniques of improving refinery reliability, profitability and availability. We studied corrosion control document (CCD) in the crude distillation unit (CDU) process. Recent studies show the Loss due to corrosion in the U.S.A. is 276 billion dollars per year. Therefore, both managers and engineers of refinery industry are always concerned about reliability of equipments related to corrosion. The CCD consists of numerous parts namely damage mechanisms (DM), design data, critical reliability variables (CRV), guidelines, etc. The first step in development of CCD is to draw material selection diagrams (MSD). It is needed to choose the DM of each process effecting equipments that are based on API (American Petroleum Institute) 571. The selected nine DM from API 571 (nineteen DM are exist) are (1) creep/stress rupture, (2) Fuel Ash Corrosion, (3) Oxidation, (4) High Temperature Sulfidation, (5) Naphthenic Acid Corrosion, (6) Hydrochloric Acid (HCL) Corrosion, (7) Ammonium Chloride (Salt) Corrosion, (8) Wet H2S Corrosion and (9) Ammonia Stress Corrosion Cracking. Each of DM related to corrosion of CDU process was selected by design data, P&ID, PFD, corrosion loop, flow of process, equipment's history and experience. Operating variables affecting severity of DM are selected in initial stage of CRV. After the CRV were set, we suggested the guidelines for reliability of equipments. The CCD we have been developed is the basis of the corrosion control in refinery industry. It also improves the safety of refinery process and reduces the cost of corrosion greatly.