QUANTITATIVE RISK ASSESSMENT OF A DELAYED COKER UNIT

Abstract

Risk assessment is a step in a risk management process. Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat (also called hazard). Quantitative risk assessment requires calculations of two components of risk R, the magnitude of the potential loss L, and the probability p, that the loss will occur. Here provide the general guidelines and steps on how to develop a quantitative risk assessment for a delayed coker unit in refinery, and how to use it and interpret the results. The main inputs and key elements of the quantitative risk assessment are plant maintenance history, component failure data, human errors, operation and engineering experience, and plant design documentation such as operating manuals, process flow diagrams (PFD) and piping and instrumentation diagrams (P&ID). In the present study has the Quantitative Risk assessment of delayed coker unit, for that firstly made the HAZOP study of Coker fractionators which give the idea about the exposure which will take place in plant. Secondly for calculating the frequency of hazard here discussed the fault tree analysis of coker fractionator. Which give the approximate value of top event probability (TEP). From that value calculate the risk for a unit by putting the TEP value in the various risk acceptance criteria of various countries. For calculating the consequence of the incident here used ALOHA (Areal Locations of Hazardous Atmospheres) software. Which give the thermal (heat), and dispersion effect of the incident.