QUANTITATIVE RISK ASSESSMENT (QRA) OF A PETROLEUM REFINERY

Abstract

The growing importance in the area of environment protection is forcing Chemical Process Industry (CPI) to use the state-of-the-art technology. This in turn increased the complexity of the process. The diversity in the products manufactured by CPI has made it more and more common for these industries to use reactors, conduits and storage vessels in which hazardous substances are handled at extreme conditions. The accidental release of the inventory results in toxic release, fires and explosions. The increased public awareness towards this issue has prompted the authorities to develop tools and techniques for carrying out risk analysis and assessment of CPIs. This Quantitative Risk Assessment (QRA) does not end with the identification and analysis of hazards but it also provides valuable inputs for the formulation of the Emergency Procedures and the Risk Management Plans. In this report, a comprehensive literature review along with a general QRA methodology is presented. Risks associated with Hindustan Petroleum Corporation Limited refinery facilities were assessed as a case study. This was the first oil refinery on the East Coast and the first major industry in the city of Visakhapatnam, Andhra Pradesh. Initially major hazards in the plant were identified. Based on this, consequence analysis and frequency analysis were performed for all the events which include the selection of methodology to describe the consequence and attaching probability to estimate the frequency. For some events fault trees were also drawn to find the frequency. Finally, the results from the consequence analysis were presented in terms of damage distance from the release point. Individual risk contours were plotted for LPG storage, which was the worst case scenario. The F-N curve was drawn to present the societal risk. Various changes were recommended to ensure that the risk posed to the society comes into the acceptable region.