Considerations of process flexibility in design of chemical processes for satisfaction of economic and environmental objectives

This paper explores a method by which considerations of process flexibility can be examined along with economic and environmental objectives during process design. A new index of process flexibility is developed, which relies on the assertion that only those design conditions leading to simultaneous enhancement of economic and environmental performance over a base case design are desirable. The approach is demonstrated for an ammonia-nitric acid plant combination, with energy integration. Some suggestions are offered on how this approach might be extended to a fuller consideration of operability issues.