In this research, a risk-based shutdown inspection and maintenance interval optimization for a processing facility is proposed. Often inspection and maintenance activities can’t be performed until the processing unit or plant is taken into a non-operational state, generally known as “shutdown”. Extensive work on inspection and maintenance interval estimation modeling is available in the concerned literature however, no to very limited application on shutdown inspection and maintenance modeling is observed for a continuous operating facility. Majority of the published literature deals to optimize individual equipment inspection and maintenance interval without considering the overall impact of plant unavailability due to shutdown. They all deal to optimize individual equipment inspection and maintenance interval considering cost, risk, availability and reliability. The efforts towards finding an optimal inspection and maintenance interval is not considered in these studies especially when it requires unit or plant to be in shutdown state from an operational state for performing inspection and maintenance. This topic is selected to bridge the existing gap in the available literature and to provide a means to develop a methodology to estimate the shutdown inspection and maintenance interval for a continuous processing unit or plant, rather an inspection and maintenance interval for each piece of equipment considering the overall asset availability, reliability and risk.
A component failure due to wear or degradation is a major threat to asset failure in a processing facility. A carefully planned inspection and maintenance strategy not only mitigate the effects of age-based degradation and reduce the threat of failure but also minimize the risk exposure. Generally failure caused by wear or degradation is modeled as a stochastic process. For an effective inspection and maintenance strategy, the stochastic nature of failure has to be taken into consideration. The proposed methodology aims to minimize the risk of exposure considering effect of failure on human life, financial investment and environment by optimizing the interval of process unit shutdown. Risk-based shutdown inspection and maintenance optimization quantifies the risk to which individual equipment are subjected and uses this as a basis for the optimization of a shutdown inspection and maintenance strategy
