Part III
Moving Beyond the Plant Boundary

Overview

Part II presented tools for evaluating and improving the environmental performance of chemical processes, but the analysis ended at the boundary of the flowsheet. While it is appropriate for chemical engineers to focus on the process flowsheet, where the chemical process design engineer has the most control, it is also important to recognize that chemical manufacturing processes are linked to both suppliers and customers. Customers will be concerned about the environmental performance of chemical products that they use, and so process design engineers must increasingly become stewards for their products. In addition, chemical processes are linked to their suppliers, so engineers must be aware of the linkages between their processes and other chemical processes and other industrial sectors. The group of chapters listed below addresses these issues of product stewardship and industrial networks.

1. Chapter 13, covering life-cycle assessment, presents emerging product stewardship tools.

2. Chapter 14, covering industrial ecology, presents tools for analyzing mass and energy flows within networks of industrial processes.

More specifically, Chapter 13 presents a methodology for tracking the flows of energy, materials, and waste streams required in the manufacture, use, and disposal of products. This methodology, called life-cycle assessment, is used to identify opportunities for improving the environmental performance of products throughout their life cycle, from raw material extraction to waste disposal. Chapter 13 covers the basic principles of life-cycle assessment, and demonstrates the applications and limitations of the methodology through a series of case studies. Chapter 14 examines the flows of energy, materials, and wastes among industrial sectors. These studies attempt to identify potential exchanges of material and energy between industrial processes that create the type of symbiotic relationships often found in ecosystems—hence the name industrial ecology. Chapter 14 illustrates the principles of industrial ecology through a number of case studies.