Trade-Off Economics for Refinery and Plant Turnarounds

Plant turnaround economics are highly complex. There are many variables which impact the overall business performance of a turnaround and multiple trade-offs need to be considered. Decision-making in this very dynamic environment however has often been based on assumptions. This paper explores the fundamental relationships between the major cost-contributing factors such as shift-patterns, labor productivity, and turnaround duration, fixed costs, quality and lost opportunity costs. Once basic relationships between these variables are established the paper then proposes a generic turnaround trade-off model and a case study is then presented to illustrate –through the use of sensitivity analysis- the impact of specific trade-off decisions upon overall economic viability of the turnaround. This research study is based on more than five hundred turnaround events with detailed performance data.