626f Chemical Process Design: An Enduring Philosophy for a Changing Profession

Richard Turton and Joseph A. Shaeiwitz. Chemical Engineering, West Virginia University, 453 Engineering Sc. Building, P.O. Box 6102, Morgantown, WV 26506

The purpose of the Chemical Process Industry (CPI) is, and has always been, to convert lower value raw materials to higher value products. As with all optimization problems, the optimal solution depends on the objective function and the constraints imposed on the problem. A century ago, these constraints were dominated by technology and economics, with few governmental restrictions. Over the years, the impact of the CPI on the environment has become clearly evident. These environmental concerns add additional constraints to the optimization problem, just as improvements in processing technology, materials of construction, catalysts and increasing raw material prices have imposed or relaxed other constraints. In addition, more efficient solution algorithms, faster computers, better simulators, more accurate design tools, and improved design algorithms have expanded the feasible region over which we search for solutions.

A significant change in the type and scale of chemical processes in the US over the last 20 years has led to greater emphasis on batch processing. With these changes, chemical engineers must reconsider some traditional design heuristics, such as those associated with specialty products that differ from those associated with commodity chemicals. These heuristics include packaging, plant layout, product scheduling, unit costing, prototyping (for medical devices and systems), scale-up, and economies of scale. There is no doubt that the number and complexity of issues surrounding the decision to invest in a new process or to optimize an existing process have increased. Nevertheless, the methodology to optimize a chemical process has remained essentially the same. The need to be able to focus on the “big picture” and not get bogged down in all the details is still of paramount importance. Our emphasis at WVU has been to focus on the process as a whole (process design) with less emphasis on equipment design (plant design). It is the presenters' philosophy that no matter how the technical and political landscape changes, the fundamental aspects of process evaluation, process design, and process optimization will remain the same, but the constraints and tools will change.