This study focuses on the techniques of improving refinery reliability, profitability, and availability. In this study, a corrosion control document (CCD) knowledge base system in crude oil distillation unit process is developed. CCD consists of numerous parts namely damage mechanisms (DM), design data, critical reliability variables (CRV), guidelines, etc. To develop CCD, first off, a material selection diagrams (MSD) is drawn. The DM of each process effecting equipments that are based on American Petroleum Institute 571 should be chosen. Operating variables affecting severity of DM are selected in the beginning stage of CRV. Finally, guidelines are provided for the reliability of equipments.