Process safety in oil refineries: Semi-quantitative HAZOP in vacuum distillation column case

The holes in the process safety cause major accidents. Possible errors that can occur in the identification studies for hazards and risks which is one of the elements of process safety management cause resulting major accident having undesirable long - term effects on human and environment. For preventing major accidents, identification and analysis of process hazards due to equipment failures, manufacturing design or montage defects, improper maintenance, misuse, material defects, metal fatigue, corrosion, welding defects, human failure etc. are the main principles of process safety management. The aim of present study is to investigate possible accidental risks occurring in Vacuum Distillation Column of oil refining within contributing to the process safety frame. In this cross - sectional study, semi quantitative HAZOP analysis was used for identifying accidental risks. By means of HAZOP studies 66 possible deviations, 238 deviation reasons, 287 results, 651 barriers and 113 proposals were identified. In the determination of accidental risk in the vacuum distillation column by applying semi quantitative HAZOP analysis method, effective results were obtained. The most common causes of deviations in the column have been found as control loop failure, leakage and mechanical failure. It is stated that the most common accidental risks are as a portion of 66.9 % operational deterioration, fire, explosion, release known as major accident risk. It is identified that the accidental risks mostly cause existence damage and the highest accidental risk occurs in the "vacuum column over head system" and "bottom of the vacuum column system" 87.7 % of 113 the proposed recommendations are changes in the plant design, 5.3% is about changes in the process safety management system."