(387d) Root-Cause Analysis in the Design of Chemical Processes

Root-Cause Analysis techniques have found widespread application in quality control, management, failure analysis and process safety. A sustainability root-cause analysis is a powerful tool that will enable designers to identify and display the fundamental causes, related causes and root causes that impact the sustainability of a process. This facilitates the understanding of potential interrelationships between causes which lead to the sustainability issue. A base case in the design of chemical/energy systems generally has high potential for improvement. The challenge is to identify the bottleneck issues that can have a significant impact on overall sustainability.

The Pareto chart and the Fish-bone diagram, in conjunction with the sustainability metrics, form the framework of the sustainability root-cause analysis. The sustainability assessment incorporates economic, environmental, societal, and efficiency criteria. Because of the multi-dimensional feature of sustainability, accounting for the impacts of various design factors and the cause-and-effect relationships can be very difficult. After selecting a process from a group of alternative designs, it is further examined in a root-cause analysis, to identify the major causes that affect the parameters considered in the sustainability assessment, and then eliminate them with appropriate corrective action.

To illustrate the use of the sustainability root-cause analysis tools, several case studies including biodiesel production, polygeneration and natural gas reforming are employed. The Pareto analysis and Fish-bone diagram are invaluable aids to visualize complex relationships and screen out significant factors and correlations for sustainability improvement. This methodology can provide critical guidance to design for sustainability.