Availability assessment of a two-unit stand-by pumping system

The paper aims at assessing the availability of a critical pumping system of the Crude Distillation Unit of a refinery with recourse to the Markovian model. Actual field data on failure and the repair times have been collected and analyzed by fitting exponential distribution. Also a simulation model has been developed for assessing the system availability. The availabilities based on both the analytical and the simulation models have been compared. The simulation model has been used for predicting system availability for varying failure and the repair rates. The repair strategies for the increasing failure rate in order to attain the desired availability have also been discussed in the paper.