Feature pubs.acs.org/journal/ascecg
Green Engineering Education in Chemical Engineering Curricula: A Quarter Century of Progress and Prospects for Future Transformations David T. Allen,*,† David R. Shonnard,‡ Yinlun Huang,§ and Darlene Schuster∥ †
Department Department § Department ∥ Institute for ‡
of Chemical Engineering, University of Texas, Austin, Texas 78712, United States of Chemical Engineering, Michigan Technological University, Houghton, Michigan 49931, United States of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan 48202, United States Sustainability, American Institute of Chemical Engineers, New York, New York 10005, United States
ABSTRACT: Over the past 25 years, the inclusion of sustainability and green engineering content in chemical engineering curricula has increased significantly. Currently, most chemical engineering students have the opportunity to learn green engineering tools and principles through elective courses; the evolution to this current state of practice is described, along with the challenges associated with fully integrating Green Engineering and sustainability concepts and tools into the courses required of all chemical engineering students.
KEYWORDS: Sustainability education, Chemical engineering curricula, Courses, Course modules, Sustainability certificate
T
evolution toward a broader focus on all dimensions of sustainability.
he inclusion of Green Engineering tools and principles in chemical engineering education has grown and evolved over the past 25 years, and that growth and evolution is poised to continue. Part of this evolution has been to move from the primarily environmental focus of Green Engineering to the broader concept of sustainability, where sustainability can be defined as “a path forward that allows humanity to meet current environmental and human health, economic, and societal needs without compromising the progress and success of future generations”.1 In engineering, incorporating a concern about sustainability into products, processes, technology systems, and services means integrating environmental, economic, and social factors in the evaluation of products and designs. Quantitative tools available to engineers seeking to design for sustainability are continually evolving, but currently focus primarily on natural resource conservation and emission reduction. Few quantitative tools are currently available for incorporating social dimensions of sustainability into engineering design, and consequently, the societal dimensions of sustainability receive less emphasis than the environmental and economic dimensions, in engineering education. In reviewing the historical evolution of sustainable engineering education, this Feature will focus on the incorporation, into chemical engineering curricula, of tools for characterizing and minimizing the environmental impacts and natural resource consumption associated with chemical processes and chemical products, referred to here as Green Engineering. This Feature will then chart a tentative roadmap for the next decade, including the © 2016 American Chemical Society
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EVOLUTION OF GREEN ENGINEERING CONTENT IN CHEMICAL ENGINEERING CURRICULA A quarter of a century ago, in the early 1990s, Green Engineering (at the time, referred to as pollution prevention) had a limited presence in chemical engineering education. Engineering practice was changing, however, driven by legislation, such as the Pollution Prevention Act of 1990, and escalating costs of waste management. A growing community of university-based researchers was also emerging, developing green chemistry and Green Engineering innovations;2,3 these researchers were often receptive to the incorporation of Green Engineering principles and tools into the courses that they were teaching. This situation created a receptive environment for Green Engineering course modules, often in the form of homework and design problems, which could be assigned in traditional engineering courses. In the United States, in 1992, the American Institute of Chemical Engineers distributed a Special Issue: Building on 25 Years of Green Chemistry and Engineering for a Sustainable Future Received: June 24, 2016 Revised: October 3, 2016 Published: October 4, 2016 5850
DOI: 10.1021/acssuschemeng.6b01443 ACS Sustainable Chem. Eng. 2016, 4, 5850−5854
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operation and flowsheet levels. Assessment tools often quantify energy use, water use, material use and emissions associated with designs. The assessments can also include tools that partially monetize the sustainability measures. The design tools include both general principles, such as the 12 principles of Green Engineering,3 as well as more quantitative analyses of materials, unit operations, and flowsheets. Often, this involves use of groups of computer-aided design tools, such as those shown in Figure 1. Systems Perspectives. Engineering designs are embedded within systems, and system analysis skills are a critical component of Green Engineering education. Figure 2 illustrates the multiple types of systems that engineering designs can simultaneously influence, using the production of biofuels as a case study. At one level of these embedded systems are the environmental impacts of the fuels, which can be assessed based on their molecular structure. At a larger scale, design of raw material supply and biofuel processing systems can be considered. At even larger scales, the impact of the use of food crops for manufacturing fuels, and the interaction of the fuel design with vehicle design can be considered. Finally, the overall performance of systems should consider the impacts on land and water use and the communities that are home to agricultural production. These systems perspectives introduce students to the life cycle consequences and societal dimensions of their designs. Although all of these levels of systems could, in principle, be covered in engineering curricula, in practice, only the two innermost system levels in Figure 2 have been addressed in most university level Green Engineering courses.5 Table 1 and Figures 1 and 2 provide an academic perspective on a Green Engineering Body of Knowledge for chemical engineers. In parallel, beginning at approximately the same time that the academic Body of Knowledge was developed, a Sustainable Engineering Body of Knowledge for practicing engineers emerged through the efforts of the American Institute of Chemical Engineers’ (AIChE) Institute for Sustainability, and other organizations. This Body of Knowledge for practicing engineers includes, in addition to the academic Body of Knowledge, elements associated with implementing new ideas in large and diverse organizations as well as societal impacts, which address issues such as workforce development, social responsibility (including ethics), along with stakeholder engagement. More information is provided by the AIChE’s Institute for Sustainability.8 The Body of Knowledge for sustainability professionals also aligns with the AIChE Sustainability Index, which enables companies to benchmark their sustainability practices with averages and best in class performance of similar organizations.9,10 Again, the Sustainability Index incorporates societal impacts, which in this case involve stakeholder partnerships, social investment, and image in the community.9 The Body of Knowledge for chemical engineers in industrial and academic settings are compared and contrasted in Table 2.
collection of homework and design problems related to Green Engineering that became widely used.4 Some of the problems introduced principles of life cycle assessment (LCA) within the framework of courses that covered material and energy balances for chemical processes. In this case, the general practices of Green Engineering (performing life cycle inventories), mirrored the topics covered in traditional chemical engineering instruction (material and energy balances for chemical processes), albeit applied at different spatial scales. In other courses, such as process design, new types of Green Engineering tools emerged, such as mass exchange networks (tools for improving material efficiency) and computer-aided tools for flowsheet emissions estimation, environmental fate of emitted pollutants, and impact assessment for chemical processes and products. These tools expanded the tool-box for chemical engineers. Over the course of the decade of the 1990s a sufficiently wide and coherent body of knowledge in Green Engineering emerged so that entire courses could be offered. By the early 2000s, the overwhelming majority of engineering programs in the United States had some content related to green engineering or sustainability. Murphy et al.5 documented the Body of Knowledge covered in over 150 of these courses on Green Engineering or sustainability. Based on this inventory, three general elements of a Body of Knowledge for chemical engineers in academic curricula emerged, as summarized in Table 1. The three elements can be labeled as (i) framing the challenge, (ii) assessment and design, and (iii) systems perspectives. Table 1. Green Engineering in Chemical Product and Process Design: A Body of Knowledge6 Framing the challenge
Assessment and design
System Perspectives
Introduction to environmental and natural resource challenges Overview of energy, water and material supplies and uses Overview of emissions and wastes of concern Earth systems and global material cycles Risk and life cycle frameworks for analyzing issues Legislation to protect human and ecosystem health General principles of Green Engineering Applying Green Engineering principles at a molecular scale Applying general principles at unit operation scales Applying general principles at flowsheet scale Monetizing Green Engineering metrics Applying general principles for products and materials Life cycle assessments along supply chains: tools and case studies Interindustry flows of materials and energy (an Industrial Ecology)
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Framing the Challenge. To understand the assessments and metrics that are used to characterize the Green Engineering features or sustainability of chemical processes and products, most chemical engineering students need a basic introduction to national and global patterns of energy use, water use, materials use, and emissions. Most engineering students also need introductions to the risk and life cycle frameworks used to organize and synthesize assessment data. Assessment and Design. Chemical engineers use Green Engineering tools to assess and improve the environmental and natural resource footprints of designs at the molecular, unit
RELATIONSHIP OF GREEN ENGINEERING CONTENT TO THE CORE CURRICULUM Over the past 2 decades, most of the students who have taken formal coursework in Green Engineering have been upper division undergraduate students and graduate students enrolled in elective courses.5 A small number of universities require courses that include substantial Green Engineering content,11,12 but at the undergraduate level, these programs with required Green Engineering courses are unusual. In contrast, at the 5851
DOI: 10.1021/acssuschemeng.6b01443 ACS Sustainable Chem. Eng. 2016, 4, 5850−5854
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Figure 1. Computer-aided tools for Green Engineering of chemical processes.6
Figure 2. Technological−social system of biofuel production in multiple layers; design decisions made in any of the layers shown influence decisions in all other layers (ref 6; adapted from Graedel and Allenby7).
graduate level, Green Engineering content is required in multiple interdisciplinary MS and doctoral programs (see examples in Murphy et al.5). These programs typically link chemical engineering with graduate programs in business, environmental science, and/or public policy.
Table 2. Bodies of Knowledge in Sustainability for Chemical Engineering Undergraduate Students and Practicing Chemical Engineers Body of Knowledge for Undergraduate Chemical Engineering Education
Body of Knowledge for Practicing Chemical Engineers
Framing the Sustainability Challenges Sustainability assessment and analysis tools •Molecular scale •Process scale Sustainable design and manufacturing tools Systems tools and perspectives
Strategic Commitment/Ethics Innovation Environmental Performance Safety Performance Product Stewardship Social Responsibility Value Chain Management
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PROSPECTS FOR FUTURE CURRICULAR TRANSFORMATIONS
A challenge moving forward will be fully integrating Green Engineering and sustainability concepts and tools into the courses required of all chemical engineering students. A model for this starting this transformation is the adoption of curricular 5852
DOI: 10.1021/acssuschemeng.6b01443 ACS Sustainable Chem. Eng. 2016, 4, 5850−5854
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Green chemistry, maximizing reactor yield, waste minimization, greenhouse gas reduction, natural reactants and products, catalysis, side reaction, energy minimization, bioreactors, safety and health. Modeling for sustainability; steady-state and dynamic analysis of system sustainability; energy and material management and control systems Design for Sustainability (DfS) concepts and methods; sustainability assessment; energy and material efficiency; recycle and reuse; source waste reduction; plant safety; life cycle analysis; eco-efficiency; social aspects
Energy quality, available energy (exergy), entropy minimization, cogeneration, effect of energy usage and source on the environment, prediction of environmental fate of toxic materials. Effects of a chemical’s environmental properties on pollutant transport and fate, exposure, health risk assessment, minimization of energy and water usage in unit operations
Energy efficiency and waste minimization via recycle, environmental life cycle assessment. Material balances, stoichiometry and simultaneous mass energy balances
Thermodynamic laws, entropy; heat engines; refrigeration; phase and chemical equilibria; reaction rates, reaction energy barriers, gas, liquid and solid properties Transport Microscopic momentum and heat transfer; macroscopic transport equations; unit Phenomena operations including absorption, distillation, extraction, adsorption, membrane separation Kinetics and Quantitative treatment of complex homogeneous and heterogeneous chemical reactions Reactor Design and batch, stirred and flow reactor system design Process Dynamics System modeling, dynamics; process simulation; control system design, control and Control performance analysis of industrial manufacturing systems Product and Process Design of chemical products and processes; heat and mass integration; engineering Design economics; environmentally benign design
Introduction to sustainability issues and metrics, across molecular, process and system scales; supply chains
Freshman Engineering Introduction to Chemical Engineering Thermo-dynamics
CONCLUDING THOUGHTS In the 21st century, engineering design and problem solving will continue to evolve to address not only technical feasibility and economic viability, but also environmental protection, and societal issues. A challenge for undergraduate chemical engineering education is to maintain thorough technical instruction while also incorporating global perspectives, leadership, environmental literacy, sustainability, and many other attributes. Although the inclusion of these new educational elements is limited by an already overcrowded curriculum, modular instruction as supplements to existing core courses offers opportunities for including Green Engineering education in existing curricula as well as in life-long learning programs. An additional and immediate challenge for Chemical Engineering education will be to add a consideration of the societal dimensions of engineering designs to the Green
Main Course Content
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Course
Table 3. Core Course Description and Integration of Sustainability and Green Engineering
Representative Sustainability Content To Be Included
materials on chemical process and product safety, developed and disseminated through the AIChE Center for Chemical Process Safety.13 Over the past decade, the incorporation of chemical safety into chemical engineering curricula has received increasing attention from organizations that accredit chemical engineering curricula. In response, the AIChE Center for Chemical Process Safety has developed a series of online educational modules that students and practicing engineers can complete. If a core group of modules is successfully completed, a certificate is awarded.13 Increasing numbers of chemical engineering academic departments are now requiring that students complete these modules as part of required courses. This approach exposes students to ongoing professional education (in this case through the AIChE) that can build life-long learning habits. It also allows academic departments that either cannot find lecture time in a crowded curriculum for process safety content, or that do not have faculty with expertise in chemical process safety, to offer safety content as part of their curricula. The disadvantage of this approach is that it can create the impression that safety is disjoint from the rest of the chemical engineering curriculum. Moving forward, an approach for integrating Green Engineering content in chemical engineering curricula would be to preserve the advantages of the online education offered through a professional society, with other elements that provide more integration with classroom instruction. One way to accomplish this would be to continue to use online modules that can be completed with limited instructor involvement. Students would earn certificates for completing modules, issued by the AIChE, analogous to safety modules. In addition to the online modules, materials could be created that allow instructors to supplement the online material with in-class activities. These Green Engineering or sustainability modules could provide a method to meet and assess required student accreditation outcomes, which include (i) “an ability to design a system, component, or process to meet desired needs with realistic constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability”, and (ii) “the broad education necessary to understand the impact of engineering solutions in a global, economic, environmental, and social context”.14 Table 3 provides descriptions of educational modules that could be developed within this framework, ranging from freshman engineering, through core courses on thermodynamics and transport phenomena, to capstone design courses.
Introduction to the engineering design process
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DOI: 10.1021/acssuschemeng.6b01443 ACS Sustainable Chem. Eng. 2016, 4, 5850−5854
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AUTHOR INFORMATION
Corresponding Author
*D. T. Allen. E-mail:
[email protected]. Notes
The authors declare the following competing financial interest(s): Two of the authors (D.R.S., D.T.A.) are the authors of a widely used text on Green Engineering. These authors receive no royalties on the sales of that book.
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REFERENCES
(1) National Research Council. Sustainability in the Chemical Industry; National Academy Press: Washington, DC, 2006. (2) Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press, New York, 1998. (3) Anastas, P. T.; Zimmerman, J. B. Design through the 12 principles of green engineering. Environ. Sci. Technol. 2003, 37 (5), 94A−l01A. (4) Allen, D. T., Bakshani, N.; Rosselot, K. S. Pollution Prevention: Homework and Design Problems for Engineering Curricula; American Institute of Chemical Engineers: New York, 1992. (5) Murphy, C.; Allen, D. T.; Allenby, B.; Crittenden, J.; Davidson, C.; Hendrickson, C.; Matthews, S. Sustainability in Engineering Education and Research at U.S. Universities. Environ. Sci. Technol. 2009, 43, 5558−5564. (6) Allen, D. T.; Shonnard, D. R. Sustainability in Chemical Engineering Education: Identifying a core body of knowledge. AIChE J. 2012, 58 (8), 2296−2302. (7) Graedel, T. E., Allenby, B. R. Industrial Ecology and the Automobile; Prentice Hall: Englewood Cliffs, 1997. (8) AIChE Institute for Sustainability (IfS) (2016) available at: http://www.aiche.org/ifs/resources/sustainability-credentials. (9) Cobb, C.; Schuster, D.; Beloff, B.; Tanzil, D. The AIChE Sustainability Index: The Factors in Detail. Chem. Eng. Prog. 2009, 105 (1), 60−63. (10) Chin, K.; Schuster, D.; Tanzil, D.; Beloff, B.; Cobb, C. Sustainability Trends in the Chemical Industry. Chem. Eng. Prog. 2015, 111 (1), 36−40. (11) Slater, C. S.; Hesketh, R. P.; Fichana, D.; Henry, J.; Flynn, A. M.; Abraham, M. Expanding the Frontiers for Chemical Engineers in Green Engineering Education. Int. J. Eng. Educ. 2007, 23 (2), 309− 324. (12) Zheng, K.; Bean, D. P.; Lou, H. H.; Ho, T. C.; Huang, Y. Education Modules for Teaching Sustainability in a Mass and Energy Balance Course. Chem. Eng. Educ. 2011, 45 (4), 265−275. (13) AIChE Center for Chemical Process Safety (CCPS) (2016). Available at: http://www.aiche.org/ccps/resources/ccpsp-certifiedprocess-safety-professional. (14) Accreditation Board for Engineering and Technology (ABET) (2016). Available at: http://www.abet.org/accreditation/accreditationcriteria/criteria-for-accrediting-engineering-programs-2016-2017/. (15) Byrne, E. P.; Desha, C. J.; Fitzpatrick, J. J.; Hargroves, K. Exploring sustainability themes in engineering accreditation and curricula. International Journal of Sustainability in Higher Education 2013, 14 (4), 384−403. 5854
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