Green Engineering Environmentally Conscious Design of Chemical Processes

A chemical engineer's guide to managing and minimizing environmental impact. Chemical processes are invaluable to modern society, yet they generate substantial quantities of wastes and emissions, and safely managing these wastes costs tens of millions of dollars annually. Green Engineeringis a complete professional's guide to the cost-effective design, commercialization, and use of chemical processes in ways that minimize pollution at the source, and reduce impact on health and the environment. This book also offers powerful new insights into environmental risk-based considerations in design of processes and products. First conceived by the staff of the U.S. Environmental Protection Agency, Green Engineeringdraws on contributions from many leaders in the field and introduces advanced risk-based techniques including some currently in use at the EPA. Coverage includes: Engineering chemical processes, products, and systems to reduce environmental impacts Approaches for evaluating emissions and hazards of chemicals and processes Defining effective environmental performance targets Advanced approaches and tools for evaluating environmental fate Early-stage design and development techniques that minimize costs and environmental impacts In-depth coverage of unit operation and flowsheet analysis The economics of environmental improvement projects Integration of chemical processes with other material processing operations Lifecycle assessments: beyond the boundaries of the plant Increasingly, chemical engineers are faced with the challenge of integrating environmental objectives into design decisions. Green Engineeringgives them the technical tools they need to do so.

DAVID T. ALLEN, Reese Professor of Chemical Engineering and the Director of the Center for Energy and Environmental Resources at the University of Texas at Austin, was the 2000 recipient of the American Institute of Chemical Engineers Lawrence K. Cecil Award in Environmental Chemical Engineering for his contributions to air quality and pollution prevention engineering and environmental engineering education.

DAVID R. SHONNARD, Associate Professor of Chemical Engineering at Michigan Technological University, is a 1998 recipient of the NSF/Lucent Technologies Foundation Industrial Ecology Research Fellowship for research that integrates environmental impact assessment with process design. Other related awards include an NSF-funded repository for pollution prevention curriculum development materials.

With contributions by authors from US EPA and Industry.

Preface Chemical processes provide a diverse array of valuable products and materials used in applications ranging from health care to transportation and food processing. Yet these same chemical processes that provide products and materials essential to modern economies also generate substantial quantities of wastes and emissions. Managing these wastes costs tens of billions of dollars each year, and as emission and treatment standards continue to become more stringent, these costs will continue to escalate. In the face of rising costs and increasingly stringent performance standards, traditional end-of-pipe approaches to waste management have become less attractive and a strategy variously known as environmentally conscious manufacturing, eco-efficient production, or pollution prevention has been gaining prominence. The basic premise of this strategy is that avoiding the generation of wastes or pollutants can often be more cost effective and better for the environment than controlling or disposing of pollutants once they are formed. The intent of this textbook is to describe environmentally preferable or "green" approaches to the design and development of processes and products. The idea of writing this textbook was conceived in 1997 by the staff of the Chemical Engineering Branch (CEB), Economics, Exposure and Technology Division (EETD), Office of Pollution Prevention and Toxics (OPPT) of the US EPA. In 1997, OPPT staff found that, although there was a growing technical literature describing "green" approaches to chemical product and process design, and a growing number of university courses on the subject, there was no standard textbook on the subject area of green engineering. So, in early 1998, OPPT initiated the Green Engineering Project with the initial goal of producing a text describing "green" design methods suitable for inclusion in the chemical engineering curriculum. Years of work, involving extensive interaction between chemical engineering educators and EPA staff, have resulted in this text. The text presents the "green" engineering tools that have been developed for chemical processes and is intended for senior-level chemical engineering students. The text begins (Chapters 1-4) with a basic introduction to environmental issues, risk concepts, and environmental regulations. This background material identifies the types of wastes, emissions, material use, and energy use to determine the environmental performance of chemical processes and products. Once the environmental performance targets have been defined, the design of processes with superior environmental performance can begin. Chapters 5-12 describe tools for assessing and improving the environmental performance of chemical processes. The structure of the chapters revolves around a hierarchy of design, beginning with tools for evaluating environmental hazards of chemicals, continuing through unit operation and flowsheet analysis, and concluding with the economics of environmental improvement projects. The final section of the text (Chapters 13 and 14) describes tools for improving product stewardship and improving the level of integration between chemical processes and other material processing operations. It is our hope that this text will contribute to the evolving process of environmentally conscious design. Draft manuscripts of this text have been used in senior-level engineering elective and required courses at the University of Texas at Austin, Michigan Technological University, the University of South Carolina, and West Virginia University. It is suggested, in a typical semester, all of the material in the text is presented. Portions of the textbook have been and can be used in a number of other chemical engineering courses as well as other engineering or environmental policy courses. Dr. David T. Allen, University of Texas, Austin Dr. David R. Shonnard, Michigan Technological Unive