Phillip C. Wankat

Rate-controlled separations

Preface. 1. Introduction. Part I: Crystallization. 2. Crystallization and Precipitation from Solution - Equilibrium Analysis. 3. Nucleation and Crystal Growth. 4. Population Balances and Crystal Size Distributions. 5. Crystallization from the Melt. Part II: Sorption and Chromatography. 6. Basics of Sorption in Packed Columns. 7. Linear Theories of Sorption and Chromatography. 8. Non-Linear Theories and Packed Bed Adsorption Systems. 9. Ion Exchange. 10. Moving Bed and Simulated Moving Bed Sorption Separations. 11. Electrophoretic Separation Methods. Part III: Membranes. 12. Introduction to Membrane Separations. 13. Detailed Theories for Membrane Separations. Part IV: Selection and Sequencing. 14. Selection and Sequencing of Separations. Appendix: Answers to Selected Problems. Index.

Five Major Shifts in 100 Years of Engineering Education

In this paper, five major shifts in engineering education are identified. During the engineering science revolution, curricula moved from hands-on practice to mathematical modeling and scientific analyses. The first shift was initiated by engineering faculty members from Europe; accelerated during World War II, when physicists contributed multiple engineering breakthroughs; codified in the Grinter report; and kick-started by Sputnik. Did accreditation hinder curricular innovations? Were engineering graduates ready for practice? Spurred by these questions, the Accreditation Board for Engineering and Technology (ABET) required engineering programs to formulate outcomes, systematically assess achievement, and continuously improve student learning. The last three shifts are in progress. Since the engineering science revolution may have marginalized design, a distinctive feature of engineering, faculty members refocused attention on capstone and first-year engineering design courses. However, this third shift has not affected the two years in between. Fourth, research on learning and education continues to influence engineering education. Examples include learning outcomes and teaching approaches, such as cooperative learning and inquiry that increase student engagement. In shift five, technologies (e.g., the Internet, intelligent tutors, personal computers, and simulations) have been predicted to transform education for over 50 years; however, broad transformation has not yet been observed. Together, these five shifts characterize changes in engineering education over the past 100 years.

Kinetic study of the conversion of different substrates to lactic acid using Lactobacillus bulgaricus

Lactic acid fermentation includes several reactions in association with the microorganism growth. A kinetic study was performed of the conversion of multiple substrates to lactic acid using Lactobacillus bulgaricus. Batch experiments were performed to study the effect of different substrates (lactose, glucose, and galactose) on the overall bioreaction rate. During the first hours of fermentation, glucose and galactose accumulated in the medium and the rate of hydrolysis of lactose to glucose and galactose was faster than the convesion of these substrates. Once the microorganism built the necessary enzymes for the substrate conversion to lactic acid, the conversion rate was higher for glucose than for galactose. The inoculum preparation was performed in such a way that healthy young cells were obtained. By using this inoculum, shorter fermentation times with very little lag phase were observed. The consumption patterns of the different substrates converted to lactic acid were studied to determine which substrate controls the overall reaction for lactic acid production. A mathematical model (unstructured Monod type) was developed to describe microorganism growth and lactic acid production. A good fit with a simple equation was obtained. It was found experimentally that the approximate ratio of cell to substrate was 1 to 10, the growth yield coefficient (YXS) was 0.10 g cell/g substrate, the product yield (YPS) was 0.90 g lactic acid/g substrate, and the α parameter in the Luedeking‐Piret equation was 9. The Monod kinetic parameters were obtained. The saturation constant (KS) was 3.36 g/L, and the specific growth rate (μm ) was 1.14 l/h.

Pressure drop effects in the pressurization and blowdown steps of pressure swing adsorption

Abstract Linearization of Darcys law for flow through packed beds allows the incorporation of pressure drop into existing models for the non-constant pressure steps of PSA. Bed length and particle size appear as explicit variables whose effect can be studied. With rapid cycles pressure gradients do not have time to decay; therefore, pressure drop is obviously important. Shock wave behavior is observed for pressurization and an analysis based on material balances around the shock is given. Blowdown exhibits diffuse wave behavior. All solutions at the closed end reduce to limiting forms available in the literature. Further, blowdown solutions at large times indicate a non-uniform composition in the column, which means that pressure drop effects are significant during blowdown even when conventional cycling time schemes are used.

Increasing the Energy Efficiency of Extractive Distillation

Abstract New flow sheets are developed for extractive distillation when it is used to break azeotropes. Detailed simulations of the model system, ethanol–water–ethylene glycol, are used to determine the energy use and column sizes. Replacing the total condenser used for the concentration column of the classical extractive distillation design with a partial condenser and thus connecting to the second column with a vapor instead of a liquid stream can result in reductions of both heating and cooling requirements of over 20%. An additional 9% reduction in heating and cooling requirements can be obtained with a new recycle design for extractive distillation.

Cyclic Separation Processes

Abstract This review covers cyclic separation methods used for adsorption, ion exchange, and chromatographic separation processes where the cyclic parameter is a thermodynamic variable which changes the equilibrium distribution coefficients of the solutes. The cyclic methods reviewed include heatless or pressure-swing adsorption, parametric pumping, and cycling zone adsorption. These cyclic techniques have been studied as a possible preparative chromatographic separation method or for continuous production from adsorption or ion exchange columns.

Distillation-Adsorption Hybrid Processes to Separate Binary Liquid Mixtures with Homogeneous Azeotrope

Isopropanol (IPA) is a major solvent in the semiconductor industry. During production, IPA is often obtained as an aqueous mixture that forms an azeotrope. Azeotropic distillation, commonly used to separate the azeotrope, has high energy requirements. The current work explores hybrid processes pairing distillation with temperature swing adsorption (TSA) (with activated carbon) or with pressure vacuum swing adsorption (PVSA) (with 3A zeolite). The feed was 10 mol% IPA and target purity was 99.9999 mole%. Optimized distillation/adsorption hybrid schemes were compared to optimized azeotropic distillation. On the basis of total yearly costs, distillation-PVSA was found to be the most economical scheme followed by azeotropic distillation and then distillation-TSA.

Engineering Education Research in "European Journal of Engineering Education" and "Journal of Engineering Education": Citation and Reference Discipline Analysis.

The authors, citations and content of European Journal of Engineering Education (EJEE) and Journal of Engineering Education (JEE) in 1973 (JEE, 1975 EJEE), 1983, 1993, 2003, and available 2013 issues were analysed. Both journals transitioned from house organs to become engineering education research (EER) journals, although JEE transitioned first. In this process the number of citations rose, particularly of education and psychology sources; the percentage of research articles increased markedly as did the number of reference disciplines. The number of papers per issue, the number of single author papers, and the citations of science and engineering sources decreased. EJEE has a very broad geographic spread of authors while JEE authors are mainly US based. A ‘silo’ mentality where general engineering education researchers do not communicate with EER researchers in different engineering disciplines is evident. There is some danger that EER may develop into a silo that does not communicate with technically oriented engineering professors.

Guest Editorial: Cross-Fertilization of Engineering Education Research and Development

T HERE is considerable concern over the slow rate of dissemination of proven engineering education innovations [1]. One possible cause of the slow rate of dissemination is that engineering educators in different engineering disciplines seldom communicate with each other. To study this issue, the author analyzed the citations in all of the 2009 papers in the nine US engineering education journals and proceedings listed in Table I. This guest editorial presents data for the IEEE TRANSACTIONS ON EDUCATION (IEEE TRANS. EDUC.) and recommendations for all engineering educators. Since none of the engineering or science education journals can unilaterally solve the problems caused by lack of cross-fertilization and low rates of dissemination, results for other journals are being published in the following companion guest editorials and forum: the Journal of STEM Education (J. STEM Educ.), the Proceedings of the ASEE Annual Meeting, and the Proceedings of the Frontiers in Education (FIE) Conference [2]; Chemical Engineering Education (Chem. Eng. Educ.) [3]; and the Journal of Professional Issues in Engineering Education and Practice (J. Prof. Issues Eng. Educ. Practice) [4].

Use of two feeds in simulated moving beds for binary separations

Simulated moving bed (SMB) and Analog systems with two-feeds are proposed to increase the separation performance. Operation with both total and partial feeds is studied. When the two feeds have different compositions, the proposed SMB system often showed better performance than conventional SMB and Varicol systems and the Analog system with two-feeds typically achieved higher purities compared to the Analog for conventional SMB and Varicol when the number of tanks was increased. Partial-feed operation strategy for SMB and Analog systems with two-feeds often showed significant performance improvement compared to conventional SMB plus partial feed and Varicol plus partial feed. When the two feeds are identical, partial feed operation of the two-feed SMB becomes identical to partial feed operation of Varicol.