Process, Product and Sustainable Chemical Engineering Challenges (1)

e d u c a t i o n f o r c h e m i c a l e n g i n e e r s 3 ( 2 0 0 8 ) e22–e27

available at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/ece

Trends in chemical engineering education: Process, product and sustainable chemical engineering challenges Eric Favre ∗ , Véronique Falk, Christine Roizard, Eric Schaer ENSIC, Nancy Université, 1 rue Grandville, 54001 Nancy, France

a r t i c l e

i n f o

a b s t r a c t

Article history:

Teaching chemical engineering has always been faced with a dilemma: either keep in touch

Received 25 October 2007

with industry needs or incorporate new scientific concepts into the curriculum. In this paper,

Accepted 17 December 2007

a short historical analysis of the evolution of chemical engineering teaching is presented and the recent trends of the two previous facets (industry and science) are briefly reviewed. The process vs product engineering concept is proposed as one of the means to achieve

Keywords:

a better alignment between the curriculum and industry needs. A chemical engineering

Product

teaching framework, based in part on a product and a process oriented component, which

Process

has been in place in our department 5 years ago, is described and discussed. The concept of

Engineering

sustainable chemistry, including process and product considerations, which can be seen as

Sustainable chemistry

the next frontier in chemical engineering education, is finally analysed from the education

Education

point of view.

History

© 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

1.

Introduction

Chemical engineering can be broadly defined as the branch of engineering that deals with the application of sciences (e.g., mathematics, chemistry and physics) to the process of converting raw materials or chemicals into more useful or valuable products in an economical and sustainable manner (i.e., simultaneously managing resources, protecting the environment and controlling health and safety procedures). This somehow dual character of the discipline, which combines a scientific facet together with a more pragmatic one (i.e., solving the problems of industry), is represented in Fig. 1. Similarly to a tree that grows thanks to two nutrient inlets (e.g., roots and leaves), a schematic plant pattern has been used in order to show the scientific roots, which, together with the industry needs and challenges, contribute to the enlargement of the trunk (i.e., the core of our discipline). The dual character, which can be proposed as a generic one for every engineering domain, was highlighted by Danckwerts (1966). When one goes back to the historical evolution of chemical engineering, it can be seen that the discipline and the core curriculum have reacted to stimuli both from science

∗

and industry. Table 1 tentatively summarizes what could be considered as the landmarks of the discipline. It can be seen that industry or society needs, such as energy, environment, or nanotechnology, participate together with evolution of the scientific tools, to drive the changes. Paradigms in chemical engineering education have been proposed in order to attest to the major changes in the discipline. Unit operations are often considered as the first unifying paradigm of chemical engineering, (Colton, 1991; Wei, 1996; Hougen, 1977). The second paradigm appeared in 1960 with the book of Bird, Stewart and Lightfoot entitled “Transport phenomena” (Bird et al., 1960). Today, the second paradigm is as old as the first one was when this book was published and the chemical engineering community is still searching for the elusive third paradigm (Wei, 1996; Mashelkar, 1995; Landau, 1997). The needs of modern society, getting closer to the practices in industry, multiscale approach, biology, nanotechnology and manufacturing efficiency are all held out as promising challenges from which novel concepts could emerge (Astarita, 1990; Brown and Mashelkar, 1995; Krieger, 1996; Landau, 1997; Kwauk, 2004). Nevertheless, the implications of these promising tracks to the curriculum content can hardly be identified at this stage.

Corresponding author. Tel.: +33 3 83 17 53 90; fax: +33 3 83 32 29 75. E-mail address: [email protected] (E. Favre). 1749-7728/$ – see front matter © 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.ece.2007.12.002


e23

Fig. 2 – Sketch of the evolution of chemical engineering curriculum, according to Aris (1977).

Fig. 1 – Chemical engineering vision: a bridge between science and chemical process industries.

Apart from the historical evolution of the discipline, an historical review of the content of the curriculum can also be worth for comparison purposes. Fig. 2 shows such an analysis as a pictorial view for the 7 decades 1900–1970 (Hougen, 1977; Aris, 1977). The decrease of descriptive courses, the increasing ratio of hard scientific topics, the emergence of new tools (simulation, computer science) and new industry needs (biology) can be identified. At the same time, it is interesting to note that what could be termed the “size of the box” (i.e., the total time dedicated to teaching chemical engineering concepts), has significantly increased over this period. This matter of fact, which can be seen as the change from a specialty course to a full undergraduate and graduate program, remains a key concern of what will be discussed in this paper. In other words,

Table 1 – The evolution of chemical engineering 1880: Society of Chemical Engineers (G. Davis, UK) 1888: First course in Chem. Eng. at MIT (USA) 1906: American Institution of Chemical Engineers 1915: Concept of unit operations (A.D. Little) 1923: “Principles of Chemical Engineering” by Lewis et al. 1950: Chemical thermodynamics 1955: Chemical kinetics 1960: “Transport Phenomena” by Bird, Stewart & Lightfoot 1963: Chemical reaction engineering 1965: System dynamics, process control 1968: Environmental engineering 1970: Safety & risk assessment 1973: Energy 1980: Biotechnology 1985: Computing & simulation (PSE, CFD, MD) 1990: Complex systems 2000: Nanotechnology, bio (life sciences) A tentative inventory of the historical landmarks of the discipline.

should we (or could we) once more increase the box, in order to leave time for new teaching units? Or do we consider that the size of the box can by no means be changed, so that some teaching units should decrease (or disappear) if new ones are needed? Apart from the size of the box, the content obviously plays a key role and also addresses difficult questions. A subtle balance between rigorous scientific concepts and useful (but, sometimes, too empirical) tools has to be proposed. A problem solving orientation linked with industry can be attractive to student and finds increased attention in research programs as public funding decreases (leading, among others, to a money driven situation). This choice can lead to a teaching approach based on purely empirical knowledge and to a lack of concepts which are of crucial importance for any scientific domain identity (Bird, 1996). An engineer must indeed remain a problem solver. Such a subtle equilibrium between applied and fundamental aspects is very delicate to maintain, both for teaching and research purposes; as a consequence, controversial debates periodically alert to dangerous deviations of our discipline either towards too practical oriented or too fundamental activities. More precisely, the eventual decision to change the curriculum of chemical engineering should be taken according to the recent evolution of science and industry (i.e., CPI for Chemical Process Industries). A (probably oversimplified) summary of the recent trends can be described as follows: (i) In terms of objects, the number of molecules which are known and potentially handled by chemical engineers, is continuously increasing (Fig. 3a). Even though a modest ratio of those will be marketed, typically less than 1% (Agam, 1994), one could wonder on the need to make evolve the content of the curriculum with respect to this continuing trend. (ii) More interestingly, the objects which are sold by chemical industries have undergone a profound evolution. CPI products are no more sold for what they are (i.e., a molecule), but for what they do (i.e., a property or function). In other words, a chemical product is nowadays frequently a complex mixture, which has to fulfil the targets of end-use functions. This significant evolution from so-called commodity to specialty has been abundantly commented and can be considered as a major change of the chemical industry (Amundson, 1988; Charpentier, 1997; Cussler, 1999; Cussler et al., 2002; Favre et al., 2002; Hegedus, 2005). (iii) Given the interest of the CPI with products, the number of scientific papers dedicated to this topic has increased

e24


Fig. 3 – (a) Evolution (unit = thousands) of the number of molecules since 1900. (b) Number of scientific papers (in thousands) including the keywords “formulation and technology” (䊉) and “chemical engineering and product” () (Source: Chemical Abstract Services).

tremendously (Fig. 3b). It could be expected that this large research effort has provided new tools for engineers working in a product area, which could be of interest for chemical engineering education. (iv) Finally and logically, statistical analyses performed in the US and in Europe (including in our own department) confirm that an increasing number of chemical engineers are hired in industry in order to work within a product (and not strictly process) framework (Cussler, 1999; Cussler et al., 2002). Taking into account the evolution detailed through the different items above, three types of answers can be proposed: (i) First, a “business as usual” approach, which claims that the existing curriculum already fits the needs of industry. The fact that no significant change of the curriculum has been occurred over the last 40 years, while industry changed significantly, can be proposed in order to convince decision makers that the best strategy is to keep the situation unchanged in chemical engineering education. (ii) Another possibility consists of a more revolutionary approach, which calls for an in-depth overhaul of the curriculum. The so-called “curriculum of the future”, recently proposed by a group of experts in the US, with a strong emphasis on biology and nanosciences (Armstrong, 2006), can be considered to belong to this category. (iii) Finally, an adaptative approach which aims to preserve the fundamentals of the existing curriculum, with an emphasis on new teaching units dedicated to current and emerging needs, can be proposed.

In our department, we decided to apply the last approach 5 years ago. A product-centered or a process-centered elective path have been developed, in order to take into account the needs of industry. We give hereafter a brief description of this new curriculum.

2.

Product vs process engineering

2.1.

Rationale

Starting from the context of a classical chemical engineering curriculum, a series of principles were first decided in common, before the development of the new curriculum was undertaken: (i) Two distinct electives are proposed: a process-centered one and a product-centered one. This choice seems to be more relevant to the types of positions occupied by engineers in industry (Wintermantel, 1999; Hegedus, 2005). Furthermore, it offers a better distinction between the two types of teaching features than a classical commodity vs specialty analysis. Table 2 summarizes the major differences between the product and the process teaching units. It can be seen that the product engineering challenges correspond essentially to the domain where chemistry (molecular scale) and chemical engineering (continuum scale) overlap. This is typical of the so-called coarse grain challenge, which is occasionally presented as the major frontier for chemical engineering methodology in terms of complexity (Kwauk, 2004). (ii) The students get the same degree after having completed one or the other of the electives. In other words, they

Table 2 – Process vs product engineering: conceptual framework

Objects Equilibrium properties Rate processes Production Methodology Example

Process engineering

Product engineering

Gas, liquid or solid phases Efficient tools (EOS, GE) Type 1 phase transitions CFD, CRE, mass and heat transfer Classical, most often continuous unit operations Proven: simulation (Aspen), optimization Vinyl chloride

Complex (multicomponent, heterogeneous) Metastable, distributed, non-equilibrium systems Highly non-ideal systems Unconventional, most often batch operations To be built Aspirin tablet


e25

Fig. 4 – Overall framework of the product and process engineering teaching organisation developed in our department (Ensic, Nancy) since 2000.

become chemical engineers and should be able to discuss with chemists, process engineers and tackle the problems of a chemical industry. (iii) The choice of the product or process elective is free. (iv) The elective specific teaching units are limited to the last three semesters of the graduate studies. The rest of the curriculum is the same for the students. (v) No supplementary time is allocated to teaching. In other words, the size of the box (number of hours of teaching), which has been discussed before, remains unchanged.

2.2.

Curriculum and syllabus

A sketch of the content of the 5 years curriculum is shown in Fig. 4. A more detailed presentation has been published earlier (Favre et al., 2005). After 2 years of undergraduate studies, usually performed in France in special classes with a strong emphasis on mathematics, physics and chemistry, the students have a classical set of teaching units in common: chemistry (mineral, organic, analytical, physical), thermodynamics, fluid mechanics, transport phenomena, numerical methods, process control, chemical reaction engineering, separation processes, process systems engineering and unit operations. At the end of this three semester period, they are expected to be able to tackle a design project, for which the production of a given molecule of target tonnage and purity is demanded. This capstone (or design) project takes place after the three semester period and it closes the core chemical engineering teaching syllabus. At this stage, the students are asked to choose between the process or the product elective. A brief overview of the teaching blocks for each of this elective is given in Table 3. For the process elective, basically, a large amount of modelling, simulation (CFD, PSE. . .) and optimization is given. The methodology corresponds to the most advanced methods that can lead to a rigorous plant or process design. Complementary teaching units such as safety, energy uses, polymer production or biotechnology are also provided. For the product-centered elective, a completely different situation prevails. The students are first taught the properties of mostly colloidal systems (e.g., polymers, surfactants, powders, gels, finely dispersed suspensions), which correspond to a large majority to formulated products. In a second step, the largely unconventional processes which are used for product production are described with a chemical engineering approach: granulation, compaction, spray drying, emulsification, extrusion, coating. . .. It is obvious at this stage that, given the complexity of the products, the methodology which is provided is not as rigorous and as predictive as the one taught for the process part. Nevertheless, it is hoped that the con-

cepts and tools which are developed can help the students to find their way in the complex product design and engineering framework. A series of characterization techniques, dedicated to product structure analysis, is also provided. Last but not least, the students are asked to perform a product design project based on a team work, according to the four steps proposed by Cussler and Moggridge (2001): identification of consumer needs, ideas, selection and design. As examples, a single dosage gel bead for syrup preparation at home, a fluorescent hair gel or a dry sprayable paint for car tuning have been proposed in the last years. It is expected that, based on this teaching package, an efficient approach could possibly be achieved and lead to the selection and the in-depth knowledge of critical manufacturing steps. It is interesting to note that the latter was considered as the definition of chemical engineering by Astarita (1990).

2.3.

A 5 year experience feedback

After 5 years of the product vs process experience in our department, it might be wise to achieve some kind of feedback in order to evaluate the pros and cons of the new curriculum. These can be summarized as follows: (i) First, we notice the difficulty in communicating on the product engineering concept. It is obvious that this term is rather new (Cussler and Wei, 2003) and that the number of educational initiatives in this field remains limited (Costa et al., 2006). This difficulty applies both to people in industry and students. There is a frequent confusion with a strict chemistry teaching framework (often called formulation), or with materials science (especially for polymer based products). We have to continuously recall that what is taught is neither chemistry nor material science, but a chemical engineering package dedicated to product production. (ii) In terms of student choice, quite large fluctuations between the two electives have been observed from year to year. We observe that students that choose the product elective are usually more open to research and development positions. A large proportion of them continue their studies to a PhD and a significant proportion seek to go abroad after graduating. (iii) From the teaching philosophy point of view, we still have questions which remain essentially unsolved. For example: how and what to teach on biological sciences? Students have indeed a very limited knowledge in biol´ ogy after their 2 years in so-called “classes preparatoires” (Fig. 4). It is difficult to identify how to provide to them the essential concepts in biology within a mini-

e26


Table 3 – An overview of the teaching units and targets for the product engineering and the process engineering electives Teaching units Basic Chem. Eng. Curriculum

Targets

Chemistry (mineral, organic, physical, industrial, analytical) Thermodynamics Fluid mechanics Transport processes Chemical reaction engineering Separation processes Numerical techniques

Design a process or plant dedicated to the production of a molecule of given tonnage and purity.

Take into account the environment and safety aspects.

Process control Safety Process systems engineering Design project Process engineering elective

Advanced modelling and simulation techniques

Model, simulate and optimize a chemical engineering problem from the process point of view.

Computational Fluid Dynamics Advanced mass transfer and reacting systems Optimization techniques Process Intensification Polymer processing Biotechnology Applied energetics Product engineering elective

Advances in colloids and interfaces Polymer science Powders, granules, tablets

Design product through a chemical engineering approach.

Rheology Characterization techniques Product production processes (mixing, drying, emulsification, granulation, extrusion. . .) Selected end-use properties (e.g., controlled release, biodegradability. . .) Product design project

mal teaching volume (typically a 20 h teaching block). Important issues such as the structure and properties of biomolecules, enzyme and microbial kinetics, genetic engineering and biotechnology. . . have to be included somewhere in the syllabus. However, we still wonder on the best strategy to achieve this purpose. Similarly, molecular modelling seems extremely promising for understanding structure/property relationships or to understand how complex molecules or mixtures behave; but, how far should we go with molecular modelling teaching? At the moment, we restrict the teaching effort to a limited series of lectures. Should we increase this topic? Finally, we have difficulties teaching the multiscale approach, which is often at the heart of the product design rigorous understanding. How could we teach this? Which simulation tools should we use for this purpose? (iv) We have identified, through evaluation forms, the key role of the product design project. Students usually say that this exercise is extremely positive since it forces them to use different concepts and teaching units. At the same time, they can test their ability in terms of innovation, which is and more and more asked by industry (Trainham et al., 2007). Nevertheless, we, teachers, still are completely lost when student address what we call an inverse problem to us: they identified a consumer need and the corresponding product properties (step one of the product design project). But how can we translate the properties needed into a tentative formula for the product? In our lectures, an opposite approach is most often used: start-

Tackle the process/product/properties interplay (i.e., for complex states of matter).

ing from a formula, such as a polymer in solution for instance, we try to predict the properties according to scientific tools. Maybe some computing approaches could be useful to tackle this inverse problem (Westerberg and Subrahmanian, 2000). (v) Another difficulty arises from the fact that students most often do not make connections between their subjects. Apart from the product design project, how might we stimulate their ability to develop a holistic approach? (vi) Finally, students are often frustrated that we cannot offer all of the experimental support that would be needed (or dreamed of. . .) when they achieve their design project. To the best, they can carry out some modest tests, but a rigorous lab scale production and the associated product characterization can hardly be proposed for all the types of products that they invented. We do not know how to provide a decent experimental support in order not to restrain innovation.

3. Sustainable chemistry: educational challenges We will close our paper with a more prospective analysis. According to industry and experts forecasts, it might be that the next frontier of chemical engineering education will be the biology or nanotechnology revolution (National Research Council Report, 2003). This statement applies particularly for the US industry and chemical engineering curricula will prob-


ably incorporate a large dose of these disciplines in the future (Armstrong, 2006). In Europe, the need to develop a sustainable chemical industry is often presented as the inevitable driver of the future. Thus, we started to explore to what extent the new curriculum exposed in the previous section would need to be rebuilt according to sustainable chemistry requirements. A major conclusion of our analysis is that, while sustainable chemistry calls for a sound change of the objects that the chemical engineer will have to be faced to, it does not imply an in-depth rebuilt of the curriculum. We think that the best answer is again an evolution of the existing curriculum through tools such as: lab work with molecules from renewable sources, design project where sustainable chemistry constraints are taken into account, and worked exercises where the future building blocks or molecules of a sustainable chemistry industry are studied. The application of the so-called twelve principles of green engineering (McDonough et al., 2003) within the context of a design project seems to be of particular relevance. A very limited number of new teaching units or simply an extension of already existing topics would be needed: for instance, energy integration and energy analysis, biotechnology, metrics like Life Cycle Analysis, environmental impact though greenhouse gases balance. This analysis is still embryonic and far to be conclusive. Some chemical engineering departments will probably propose a completely different diagnostic and start novel curricula for teaching sustainable chemical engineering. Again, we wait for feedback from industry and colleagues to refine our views in this challenging area.

4.

Conclusion

The rapid changes of chemical industry, together with the emergence of new scientific and teaching tools, pose a formidable challenge to chemical engineering teaching. The evolution of existing curricula demands the identification of a subtle balance among competing constraints: • take care of dispersive forces (i.e., going too far into domains such as physics, chemistry or biology), • maintain the roots of the discipline (unifying concepts, built around balances, equilibrium and transport phenomena), • keep in mind the core identity of a chemical engineer (such as the ability to effectively communicate and work with chemists, physicists, biologists, and find solutions to problems such as “from beaker to plant”). We would like to close our paper with a quotation from J. Prausnitz, which gives what we consider as a clear and relevant definition of a chemical engineer: “An effective chemical engineer is someone who relates his or her special expertise to other areas of concern, someone who may focus on one part of a practical problem but also retains an overall view of where the special area intersects with others” (Prausnitz, 1996).

Acknowledgements The authors thank the reviewers for their valuable comments and suggestions.

e27

references Agam, G., (1994). Industrial Chemicals. Their Characteristics and Development. (Elsevier, Amsterdam). Amundson, N.R., (1988). Frontiers in Chemical Engineering. Research Needs and Opportunities. (National Academy Press, Washington, DC). Aris, R., 1977, Academic chemical engineering in an historical perspective. Ind Eng Chem Fundam, 16(1): 1–4. Armstrong, R.C., 2006, A vision of the curriculum of the future. Chem Eng Educ, 1: 104–109. Astarita, G., 1990, Frontiers in chemical engineering and 1992. Chem Eng Prog, 86: 55–59. Bird, R.B., 1996, Rethinking academia: restore the right priorities. Chem Eng Prog, 92: 80–83. Bird, R.B., Stewart, W.E. and Lightfoot, E.N., (1960). Transport Phenomena. (Wiley, New York). Brown, R. and Mashelkar, R., 1995, Frontiers of chemical engineering science. Chem Eng Sci, 50: 3997–4141. Charpentier, J.C., 1997, Process engineering and product engineering. Chem Eng Sci, 52: iii–iv. Colton, C.K., 1991, Perspectives in chemical engineering research and education. Adv Chem Eng, 16: 253–264. Costa, R., Moggridge, G.D. and Saraiva, P.M., 2006, Chemical product engineering: an emerging paradigm within chemical engineering. AIChE J, 52(6): 1976–1986. Cussler, E. and Moggridge, G., (2001). Chemical Product Design. (Cambridge University Press, Cambridge). Cussler, E.L., 1999, Do changes in the chemical industry imply changes in curriculum? Chem Eng Educ, 4: 12–17. Cussler, E.L., Savage, D.W., Middelberg, A.P.J. and Kind, M., 2002, Refocusing chemical engineering. Chem Eng Prog, 1: 26S–31S. Cussler, E.L. and Wei, J., 2003, Chemical product engineering. AIChE J, 49(5): 1072–1075. Danckwerts, P.V., 1966, Science in chemical engineering. Chem Eng, 7: 155–159. Favre, E., Marchal-Heussler, L., Durand, A., Midoux, N. and Roizard, C., 2005, A curriculum in chemical product engineering. Chem Eng Educ, 39(4): 264–271. Favre, E., Marchal-Heussler, L. and Kind, M., 2002, Chemical product design: research and educational challenges. Trans IChemE: Chem Eng Res Des, 80 A: 65–74. Hegedus, L.L., 2005, Chemical engineering research of the future: an industrial perspective. AIChE J, 51(7): 1870–1871. Hougen, O.A., 1977, Seven decades of chemical engineering. Chem Eng Prog, 73: 89–104. Krieger, J.H., 1996, Chemical engineering redefines itself in era of global change. Chem Eng News, 74: 10–18. Kwauk, M., 2004, Beyond transport phenomena and reaction engineering. Chem Eng Sci, 59(8–9): 1613–1616. Landau, R., 1997, Education: moving from chemistry to chemical engineering and beyond. Chem Eng Prog, 93: 52–65. Mashelkar, R.A., 1995, Seamless chemical engineering science: the emerging paradigm. Chem Eng Sci, 50: 1–22. McDonough, W., Braungart, M., Anastas, P.T. and Zimmerman, J.B., 2003, Applying the principles of green engineering to cradle to cradle design. Environ Sci Technol, 435A–441A. December Issue National Research Council, Board on Chemical Sciences and Technology., (2003). Beyond the molecular frontier. In Challenges for Chemistry and Chemical Engineering. (National Academies Press). Prausnitz, J.M., 1996, Molecular thermodynamics: opportunities and responsibilities. Fluid Phase Equilib, 116: 12–26. Trainham, J.A., Fitzerald, L. and Fox, P., 2007, Third way innovators to the rescue. AIChE J, 53(6): 1394–1398. Wei, J., 1996, A century of changing paradigms in chemical engineering. ChemTech, 26(5): 16–18. Westerberg, A.W. and Subrahmanian, E., 2000, Product design. Comput Chem Eng, 24: 959–966. Wintermantel, K., 1999, Process and product engineering achievements. Present and future challenges. Chem Eng Sci, 54: 1597–1620.

Process, Product and Sustainable Chemical Engineering Challenges (1)

Recommend Documents