Value-based optimisation of replacement intervals for critical spare components

Abstract

For competitive industries, such as mining, value-adding demands enriched methods to efficiently manage critical equipment and spare components. These components are related to lengthy shutdowns with significant financial impact. In this context, cost optimisation is a widely used principle to schedule component replacements. However, this practice traditionally does not consider external factors of interest, such as business-market conditions, which can radically change decisions. To overcome this limitation, we have proposed a criterion based on the estimation of revenues–under several commodity price scenarios–at both the component intervention period and major shutdown time-windows. The paper presents a model to guide the decision about the best epoch to replace critical components, considering the maximisation of value-adding rather than simply minimisation of costs. Such optimal interval is optimised by comparing net benefits with reliability constraints from a condition-based maintenance strategy. As result, the decision-making process is enriched by quantifying the real value of postponing or accelerating the most favourable epoch to perform a replacement. The proposed value-based approach increases business competitiveness when included as a systemic part of an asset management perspective, thus obtaining higher profitability.