Sustainability Assessment and Root Cause Analysis of Poly-Generation Systems

In sustainability assessment, the performance of the related processes is compared, considering the economic, environmental and social factors. In complicated poly-generation systems that involve energy and chemical conversion through several pathways, sustainability assessment becomes even more difficult due to the existence of multiple products and multiple feed.

The root-cause analysis framework is built on the combination of Pareto chart and the Fish-bone diagram, in conjunction with the sustainability metrics. The results of the RCA illustrate the major factors that adversely affect sustainability of each dimension. A good root-cause analysis method depends on an appropriate sustainability assessment system because of the multi-dimensional nature of sustainability.

In this paper, three poly-generation schemes involving coal and natural gas as feed are compared using a comprehensive sustainability assessment method, incorporating exergy analysis and a novel safety assessment approach to complement the economic and environmental assessment. Further, the selected case is examined in a root cause analysis, to identify the major causes that affect the sustainability performance, in order to eliminate or minimize the effect with appropriate corrective action.