Green Engineering
Environmentally Conscious Designof Chemical Processes
Prentice Hall PTR
Upper Saddle River, NJ 07458
www.phptr.com
Library of Congress Cataloging-in-Publication Data
Allen, David T.
Green engineering : environmentally conscious design of chemical processes / by David Allen and David Shonnard.
p. cm.
Includes bibliographical references and index.
ISBN 0-13-061908-6
1. Environmental chemistry—Industrial applications. 2. Environmental management.
I. Shonnard, David. II. Title.
TP155.2.E58 A54 2002
660—dc21
2001034380
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Contents
Part I A Chemical Engineer’s Guide to Environmental Issues and Regulations
1 An Introduction to Environmental Issues
1.2 The Role of Chemical Processes and Chemical Products
1.3 An Overview of Major Environmental Issues
1.4 Global Environmental Issues
1.4.3 Ozone Depletion in the Stratosphere
1.5.1.1 NOx, Hydrocarbons, and VOC’s—Ground-Level Ozone
1.5.1.5 SO2, NOx, and Acid Deposition
1.9 Waste Flows in the United States
2.3 Value of Risk Assessment in the Engineering Profession
2.4 Risk-Based Environmental Law
2.5 General Overview of Risk Assessment Concepts
2.6.1 Cancer and Other Toxic Effects
2.6.2 Hazard Assessment for Cancer
2.6.3 Hazard Assessment for Non-Cancer Endpoints
2.6.4 Structure Activity Relationshis (SAR)
2.6.5 Readily Available Hazard References
2.9.1 Risk Characterization of Cancer Endpoints
2.9.2 Risk Characterization of Non-Cancer Endpoints
3 Environmental Law and Regulations: from End-of-Pipe to Pollution Prevention
3.2 Nine Prominent Federal Environmental Statutes
3.3 Evolution of Regulatory and Voluntary Programs: From End-of-Pie to Pollution Prevention
3.4 Pollution Prevention Concepts and Terminology
4 The Roles and Responsibilities of Chemical Engineers
4.2 Resonsibilities for Chemical Process Safety
4.3 Resonsibilities for Environmental Protection
4.4 Further Reading in Engineering Ethics
Part II Evaluating and Improving Environmental Performance of Chemical Processes
5 Evaluating Environmental Fate: Approaches Based on Chemical Structure
5.2 Chemical and Physical Property Estimation
5.2.1 Boiling point and Melting point
5.2.3 Octanol-Water Partition Coefficient
5.2.7 Soil Sorption Coefficients
5.3 Estimating Environmental Persistence
5.3.1 Estimating Atmospheric Lifetimes
5.3.2 Estimating Lifetimes in Aqueous Environments
5.3.3 Estimating Overall Biodegradability
5.4 Estimating Ecosystem Risks
5.5 Using Property Estimates to Estimate Environmental Fate and Exposure
5.6 Classifying Environmental Risks Based on Chemical Structure
6.2 Occupational Exposures: Recognition, Evaluation, and Control
6.2.1 Characterization of the Workplace
6.2.3 Monitoring Worker Exposure
6.2.4 Modeling Inhalation Exposures
6.2.4.1 The Mass Balance Model
6.2.5 Assessing Dermal Exposures
6.3 Exposure Assessment for Chemicals in the Ambient Environment
6.3.1 Exosure to Toxic Air Pollutants
6.3.2 Dermal Exposure to Chemicals in the Ambient Environment
6.3.3 Effect of Chemical Releases to Surface Waters on Aquatic Biota
6.3.4 Ground Water Contamination
7.2 Green Chemistry Methodologies
7.2.4 Functional Group Approaches to Green Chemistry
7.3 Quantitative/Optimization-Based Frameworks for the Design of Green Chemical Synthesis Pathways
7.4 Green Chemistry Expert System Case Studies
8 Evaluating Environmental Performance During Process Synthesis
8.2 Tier 1 Environmental Performance Tools
8.2.5 Evaluating Alternative Synthetic Pathways
8.3 Tier 2 Environmental Performance Tools
8.3.1 Environmental Release Assessment
8.3.1.2 Release Assessment Components
8.3.2 Release Quantification Methods
8.3.2.1 Measured Release Data for the Chemical
8.3.2.2 Release Data for a Surrogate Chemical
8.3.2.4 Emissions from Process Units and Fugitive Sources
8.3.2.5 Losses of Residuals from Cleaning of Drums and Tanks
8.3.2.6 Secondary Emissions from Utility Sources
8.3.3 Modeled Release Estimates
8.3.3.1 Loading Transport Containers
8.3.3.2 Evaporative Losses from Static Liquid Pools
8.3.3.3 Storage Tank Working and Breathing Losses
8.3.4 Release Characterization and Documentation
8.3.5 Assessing Environmental Performance
8.4 Tier 3 Environmental Performance Tools
9 Unit Operations and Pollution Prevention
9.2 Pollution Prevention in Material Selection for Unit Operations
9.3 Pollution Prevention for Chemical Reactors
9.3.1 Material Use and Selection for Reactors
9.3.2 Reaction Type and Reactor Choice
9.4 Pollution Prevention for Separation Devices
9.4.1 Choice of Mass Separating Agent
9.4.2 Process Design and Operation Heuristics for Separation Technologies
9.4.3 Pollution Prevention Examples for Separations
9.4.4 Separators with Reactors for Pollution Prevention
9.5 Pollution Prevention Applications for Separative Reactors
9.6 Pollution Prevention in Storage Tanks and Fugitive Sources
9.6.1 Storage Tank Pollution Prevention
9.6.2 Reducing Emissions from Fugitive Sources
9.7 Pollution Prevention Assessment Integrated with HAZ-OP Analysis
9.8 Integrating Risk Assessment with Process Design—A Case Study
10 Flowsheet Analysis for Pollution Prevention
10.2 Process Energy Integration
10.3.2 Optimizing Strategies for Segregation, Mixing, and Recycle of Streams
10.3.3 Mass Exchange Network Synthesis
10.4 Case Study of a Process Flowsheet
11 Evaluating the Environmental Performance of a Flowsheet
11.2 Estimation of Environmental Fates of Emissions and Wastes
11.2.1 Fugacity and Fugacity Capacity
11.2.3 Reaction Loss processes
11.3 Tier 3 Metrics for Environmental Risk Evaluation of Process Designs
12 Environmental Cost Accounting
12.3 Magnitudes of Environmental Costs
12.4 A Framework for Evaluating Environmental Costs
12.5 Hidden Environmental Costs
12.7 Internal Intangible Costs
12.8 External Intangible Costs
Part III Moving Beyond the Plant Boundary
13 Life-Cycle Concepts, Product Stewardship, and Green Engineering
13.1 Introduction to Product Life Cycle Concepts
13.2.1 Definitions and Methodology
13.3 Life-Cycle Imact Assessments
13.3.4 Interpretation of Life-Cycle Data and Practical Limits to Life-Cycle Assessments
13.4 Streamlined Life-Cycle Assessments
13.4.1 Streamlined Data Gathering for Inventories and Characterization
13.4.2 Qualitative Techniques for Inventories and Characterization
13.4.3 Pitfalls, Advantages, and Guidance
13.5 Uses of Life-Cycle Studies
13.5.4 Product Design and Improvement
14.2 Material Flows in Chemical Manufacturing
14.4 Assessing Opportunities for Waste Exchanges and Byroduct Synergies
A Details of the Nine Prominent Federal Environmental Statutes
C Estimating Emissions from Storage Tanks
D Tables of Environmental Impact Potentials—Tables D-1 to D-4
E Procedures for Estimating Hidden (Tier II) Costs—Tables E-1 TO E-5
F Additional Resources—Web Resources/Online Databases/Software
Preface
Green Engineering is the design, commercialization and use of processes and products that are feasible and economical while minimizing generation of pollution at the source and risk to human health and the environment.
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 University, Houghton
Nhan T. Nguyen, U.S. Environmental Protection Agency, Washington D.C.
About the Authors
David T. Allen is the Reese Professor of Chemical Engineering and the Director of the Center for Energy and Environmental Resources at the University of Texas at Austin. His research and teaching interests lie in environmental reaction engineering, particularly issues related to air quality and pollution prevention. He is the author of three books and over 100 papers in these areas. The quality of his research has been recognized by the National Science Foundation (through the Presidential Young Investigator Award), the AT&T Foundation (through an Industrial Ecology Fellowship), and the American Institute of Chemical Engineers (through the Cecil Award for contributions to environmental engineering). Dr. Allen’s teaching has been recognized through awards given by both UCLA and the University of Texas. He received his B.S. degree in Chemical Engineering, with distinction, from Cornell University in 1979. His M.S. and Ph.D. degrees in Chemical Engineering were awarded by the California Institute of Technology in 1981 and 1983. He has held visiting faculty appointments at the California Institute of Technology, the Department of Energy, and the University of California, Santa Barbara.
David R. Shonnard is Associate Professor of Chemical Engineering at Michigan Technological University. He has a B.S. in Chemical Engineering from the University of Nevada-Reno, M.S. and PhD. Degrees in Chemical Engineering from the University of California at Davis, postdoctoral experience at Lawrence Livermore National Laboratory, and has been the visiting lecturer at the University of California at Berkley. His research and teaching interests are in the areas of environmental impact and risk assessment, process design and optimization, and environmental biotechnology. Dr. Shonnard is author of over 30 research publications and one edited book titled Emerging Separation and Separative-Reactor Technologies for Process Waste Reduction: Adsorption and Membrane System, published by the American Institute of Chemical Engineers. He has published in engineering education journals on the topic of environmental aspects of Chemical Engineering. Environmental impact assessment software under development in his laboratory has been disseminated widely to faculty at other universities for use in the process design curriculum, and he is a 1998 recipient of a NSF/Lucent Technologies Foundation Industrial Ecology Research Fellowship.
Other Authors and Contributors
Dr. Paul Anastas serves in the National Security and International Activities Division in the White House Office of Science and Technology Policy (OSTP). In addition to bilateral international activities, Dr. Anastas is responsible for furthering international public-private cooperation in areas of Science for Sustainability such as green chemistry. Prior to coming to OSTP in October of 1999, Dr. Anastas had served, since 1989, as the Chief of the Industrial Chemistry Branch of the US Environmental Protection Agency. In 1991, he established the industry-government-university partnership Green Chemistry Program which was expanded to include basic research and the Presidential Green Chemistry Challenge Awards. Dr. Anastas coauthored Chapter 7 on Green Chemistry. Prior to joining the U.S. EPA, he worked as an industrial consultant to the chemical industry in the development of analytical and synthetic chemical methodologies. Dr. Anastas is the author/editor of nine scientific and technical books including Green Chemistry: Theory and Practice which has been translated into five languages. Dr. Anastas received his M.A. and Ph.D in Organic Chemistry from Brandeis University and his B.S. in chemistry from the University of Massachusetts at Boston.
Dr. Fred Arnold, PhD., joined EPA in 1994. Previously, he was an engineer at Westinghouse and an Assistant Professor of Engineering at the University of Oklahoma. Dr. Arnold has developed several exposure models during his tenure with CEB. Dr. Arnold coauthored Chapter 2, “Risk Concepts,” and authored Chapter 6, “Evaluating Exposures,” and contributed to several portions of the book, especially homework problem development. Dr. Arnold is a licensed P.E. in two states, received his PhD in Chemical Engineering from the University of Minnesota, his MBA from College of St. Thomas, and his J.D. from George Mason University.
Mr. John Blouin joined EPA in 1997 after 29 years of experience in the chemical process industry. He is experienced in the design, construction, and operation of pilot plants and new manufacturing processes for production of catalysts, organic, inorganic biochemical and biomedical products. Mr. Blouin holds 10 US patents as a result of his development work. Mr. Blouin contributed to several portions of the book, especially Chapter 2. John received a B.S. in Chemical Engineering from the University of Massachusetts, Lowell.
Ms. Gail Froiman joined EPA in 1989 and recently moved from the Chemical Engineering branch to the TRI program in the Office of Environmental Information (OEI). She started her career as a Research Engineer with Amoco Oil Process Development. Ms. Froiman also worked on advanced control systems in Amoco’s Texas City Refinery, and as a process engineer at Vista Chemical. Ms. Froiman primarily authored Chapter 2 on Risk Concepts. Gail holds a B.S. in Chemical Engineering from Princeton University.
Mr. Scott Prothero joined EPA’s Chemical Engineering Branch in 1990. He worked for four years as a process engineer in Monsanto Chemical Company’s chlorobenzenes and nitroanalines departments before joining EPA. Mr. Prothero coauthored Chapter 8, “Evaluating Environmental Performance During Process Synthesis,” providing most of the release data in the text. Mr. Prothero received a B.S. in Chemical Engineering from Washington University in 1985.
Ms. Kirsten Sinclair Rosselot is owner of Process Profiles, a consulting firm that specializes in environmental planning and management tools. She co-authored Chapter 10, “Flowsheet Analysis for Pollution Prevention”; Chapter 12, “Evaluating Environmental Costs and Benefits”; and Chapter 13, “Life-Cycle Concepts, Product Stewardship, and Green Engineering.” Ms. Rosselot obtained her B.S. in chemical engineering with honors from the University of California, Los Angeles and is a licensed professional chemical engineer in the state of California.
Acknowledgments
The authors are grateful for the time and effort provided by US EPA staff in the development of this text. The authors especially thank Nhan Nguyen, Chief of the Chemical Engineering Branch, for conceiving the creation of this textbook and for his valuable guidance and comments, and Sharon W. Austin, the Green Engineering Coordinator, for her guidance and support. While the individuals who contributed to the writing of the text are recognized as chapter authors, many more individuals, both within and outside the EPA, were involved in editing and reviewing the text. To these reviewers, too numerous to mention individually, we extend our thanks. And finally, thanks to the many faculties who participated in workshops, in which the material in the text was presented and critiqued. Your input was enormously helpful.
In addition to the five branches and Immediate Office of the Economics, Exposure, and Technology Division (EETD), we want to give special thanks to many staff members from various divisions in the Office of Pollution Prevention and Toxics (OPPT), including the Risk Assessment Division (RAD), the Chemical Control Division (CCD), and the Pollution Prevention Division (PPD) for their valuable contributions. We would also like to thank staff members from other offices within EPA including Office of Research and Development (ORD), Office of Air Quality Planning and Standards (OAQPS), and the Office of General Counsel (OGC) for their input and advice.