DETERMINING SYSTEM RELIABILITY OF ATMOSPHERIC DISTILLATION UNIT BY USING MONTE CARLO SIMULATION METHOD

Abstract

With the increasing complexity of equipments and process as well as cost effectiveness of an operation have brought into focus a new branch of engineering known as 'Reliability Engineering'. Reliability is the probability of a device performing its purpose adequately for the period intended under the given operating conditions. Reliability of equipment is closely related with its maintainability and its availability. When we say that particular equipment is available, we mean that the component is functioning and is available for use. On the other hand, it might not be available due to breakdown or other malfunctions. When repair is undertaken, the ease with which it is brought back into operation reflects, in some measure, the maintainability character of equipment. If reliability of of the system is high, then obviously the breakdowns will be high. Similarly, if the system is capable of being repair easily (i.e., if it has high maintainability factor), then also the availability factor will be high. Present work is a systematic approach to estimate the reliability of a process plant. The study includes a live problem at a Atmospheric Distillation Unit (ADU) of a refinery requiring high level of reliability for cost effective operation. The system is modeled as a fault tree which is often used in the analysis of chemical process industries. A numerical evaluation of the fault tree assesses the characteristic safety parameter like reliability of the system. However for large and complex systems, such analysis will normally require enormous computational effort, involving the breakdown of the fault tree into minimal cut sets. An alternative approach is simulate the system using Monte Carlo Simulation Method. This present work presents Reliability analysis of a Atmospheric Distillation Unit (ADU) by using Monte Carlo Simulation Method.