June 26, 2011
June 26, 2011
June 29, 2011
22.1578.1 - 22.1578.44
Unit Operations Lab BazaarThe Unit Operations Lab Bazaar is a special topics session that will be part of the poster sessionsponsored by the Chemical Engineering Division of ASEE. It is envisioned that the UnitOperations Lab Bazaar will be a sharing of information regarding novel chemical engineeringlaboratory experiments and/or experiences as well as innovations related to more traditional unitoperations laboratory and chemical engineering laboratory topics. Innovations and experiencesin terms of overall chemical engineering laboratory course design and course assessment wouldalso be legitimate topics for a poster presentation. Ideally, all participants and attendees will beable to go home with a number of ideas that might be applied to the improvement of the unitoperations and other chemical engineering laboratories at their home institutions.Abstracts describing the proposed poster submissions are included below.• Integration of Statistics into Lab Practice and Analysis A few years ago, our faculty responded to contradictory student and industrial feedback on the utility of a required statistics course in our program. Students who had taken the course, “Probability and Statistics for Engineering,” found it to be irrelevant to what they were learning in the chemical engineering curriculum. Our industrial advisory board, however, was emphatic about the need for statistics in the curriculum. Faculty response to both perspectives was to re-invent our undergraduate unit operations course to include both statistics content and its direct application in the planning of laboratory experiments and analysis of data. Originally, a three-credit course with two hours of lab and one hour of lecture, our junior- level unit operations course was expanded to four credits - a two-hour lecture and a two- hour lab. Initially, the coordination between lecture material and laboratory experiments was weak due to the sequence by which student teams advanced through the rotation of lab experiments. However, a few years of experience, input from students, and repeated adjustment of course syllabi led to good integration of just-in-time statistics with the cycle of laboratory work. Statistical concepts are reinforced in the lab, and some level of statistical analysis, often using Minitab, is included in every lab report. The statistical applications culminate in a “stats report” that is given as a team poster presentation at the end of the semester. This poster will discuss the strategy used to integrate statistics theory and lab experiments, choice of an appropriate textbook and the positive feedback of our alumni.• A Senior-Level Biological Engineering Laboratory at XXXXXXXXXX The Chemical and Biological Engineering degree at XXXXXXXXXX was initiated in the fall of 2005. The required senior-level Biological Engineering Lab course was taught for the first time in the fall of 2008. As the popularity of the degree has skyrocketed over the last three years, the size of the class has gone from nine students in the first year to two sections of 20student each in the fall of 2010. Lab modules that have been used with varying degrees of success throughout the last three years include yeast and E. coli growth in sophisticated bioreactors, E. coli bacterial growth and transfection, lysozyme enzyme stability assays, protein gel electrophoresis and Western blotting, computer modeling of biological engineering processes, “virtual” on-line simulations of bioreactors, and ion-exchange chromatography. This poster will present and discuss the experiences that the lab instructor has had in developing this lab course “from scratch”, lab modules that have worked and those that have not worked so well, as well as course assessment measures.• New Experiments on a Limited Budget for ChE Unit Operations Laboratories Four new experiments have been introduced into the second course of our two-course ChE Unit Operations capstone laboratory. Increasing class sizes provided the need, while limited funding dictated a heavy dependence on available components assembled in new ways. The experiments can all be classified as bench scale. Three emphasize chemical reaction, while one is based in process dynamics and control. The reaction experiments use inexpensive reagents available in commercial or consumer form. The first experiment uses a semi-batch reactor. The reaction is H2O2(aq) + NaOCl(aq) H2O(l) + NaCl(aq) + O2(g). The reagents used are consumer hydrogen peroxide (3% strength) and laundry bleach (6% strength). The reaction is fairly rapid, exothermic, and evolves oxygen gas. A surplus agitated bench fermentation vessel is used. The peroxide, cold from a refrigerator, is charged to the vessel. Bleach is pumped in at a fixed rate. Solution conductivity, temperature, and evolved oxygen rate are all monitored as functions of time for three different bleach feed rates. A transient model incorporating species and energy balances, together with conductivity, simulates the runs. The model is run on a math solver. All measured quantities are directly compared to the predictions. A CSTR is featured in the second experiment. A solution of erioglaucine (blue food color) is combined with water and household bleach, all at known rates, as the feed to a surplus agitated bench fermentation vessel. The feed can be introduced either above the liquid level in the vessel, or below the surface near the bottom. The effluent can be withdrawn from either the top or bottom. A typical experiment involves observation of dye conversion as a function of space-time, feed/effluent configuration, or even agitation rate. Dye conversion is determined by passing the reactor effluent through an on-line optical flow cell interrogated by a red laser beam. Transmitted intensities yield absorbances. The dye is purchased in dry form from a chemical supplier. While the first two reaction experiments are fairly well defined, the third is quite exploratory. The oxidation of a protein is carried out in a tubular flow vessel. An aqueous solution of powdered egg whites – consisting almost entirely of proteins, and available from a food ingredients supplier – is fed with household bleach at known rates through a long glass tube equipped with thermocouples at each end. The oxidation is exothermic, but little other information is available. The students are challenged to make gross, yet reasonable, assumptions about the reactor and the reaction. Simultaneous species and energy balances are solved with parameter values chosen to yield the observed temperatures. The final new experiment is a simulated CSTR with feedback temperature control. A surplus agitated fermentation vessel contains an immersed coil for flowing coolant water controlled by a proportional solenoid valve. An electrical immersion heater provides simulated reaction exothermicity. After open-loop dynamic characterization of the key components of the system, feedback control experiments are performed with a relatively inexpensive digital temperature controller. Proportional and proportional-integral control are tested with servo and regulator problems, respectively. Schematics, photographs, and sample data will be presented for each experiment.• Experiences at the Unit Operations Laboratory at XXXXXXXXXX This poster discusses the advantages and disadvantages of manual operation versus fully automated operation of the Unit Operations laboratory experiments. Ten out of the twelve experiments in our laboratory involve typical chemical engineering units such as distillation and liquid-liquid extraction columns that are pilot plant size. The construction material of these pieces of equipment is glass so the students can see the inner workings of the experiment. While there are some digital transducers in these units, most of the measurements are done manually. Most flow rates are measured with rotameters. Pressure drops are measured with glass manometers. Compositions are measured indirectly by measuring other properties such as density or electrical conductivity. It has been recommended that these laboratory experiments should be updated to allow computer data acquisition of all pertinent parameters. This will involve replacing all the old measuring devices with digital ones that can be connected to a computer. While there are advantages to this approach, we believe that some learning experiences may be lost in the process of automating everything. The advantages and disadvantages of these two approaches are discussed in this poster using specific examples related to our Unit Operations Laboratory experiments.• Simulating Heat Exchanger Fouling for Unit Operations Laboratory Experiments The shell and tube heat exchanger is a common unit operations laboratory experiment. It introduces the students to industrial heat transfer equipment operation as well as providing them a means to apply transport phenomena theory to a real apparatus. A downside of the heat exchanger is the limited number of experiments that can be performed. Typical experiments involve calculating an experimental overall heat transfer coefficient and comparing to a correlated value. Comparative studies of the overall heat transfer coefficient for countercurrent versus concurrent operation can also be performed if the apparatus is appropriately piped. Comparing the effectiveness of different fluids is another possibility but water is usually used as both the hot and cold fluid due to cost and safety considerations. Another potential experiment is to evaluate the fouling in the heat exchanger. This experiment can be difficult because the level of fouling in laboratory heat exchangers is very low due to the fluids used and the short time period the heat exchangers are in use. The University of Dayton has designed and assembled a 1-2 pass shell and tube heat exchanger for the unit operations laboratory. This exchanger consists of 32 copper tubes inside a glass shell. Water is heated in a hot water tank and pumped through the tubes while cold city water flows through the shell. Both flows are measured and adjusted with rotameters. The inlet and outlet temperatures of both the shell and tube flows are measured with thermocouples. During the course of the semester, the heat exchanger is modified to simulate fouling. The students operating the heat exchanger for the first experimental session are tasked with finding the overall heat transfer coefficient both experimentally and by correlation at a range of different shell and tube flows. Once the report is complete, the data for experimental heat transfer coefficient is saved for the next session. Between sessions, the heat exchanger is opened and one to two tubes are plugged which simulates fouling by reducing the available heat transfer area. Students operating the heat exchanger for the second experimental session are tasked with calculating the resistance due to fouling. They are provided with the experimental data from the previous session and told that this data was obtained when the heat exchanger was clean. These students then calculate an experimental overall heat transfer coefficient, which is less than the coefficients given in the clean data. Fouling resistance can be calculated by employing correlations from transport phenomena or creating Wilson plots. A subsequent experiment will also have a number of tubes blocked, but the students will be informed of this fact and they will attempt to determine the number of tubes that are blocked and the implications of these blockages in the heat transfer characteristics.• Integration of the Chemical Engineering Laboratory with a Focus on Bio-Fuel Production The production of renewable energy is one of the most important technological problems that we face today. This challenge also offers us an opportunity to motivate and shape the early careers of chemical engineering undergraduate students. With this goal in mind, we have designed an innovative pedagogical model for the Chemical Engineering Laboratory that is based on the central theme of producing fuels from biomass. The most innovative component of the new laboratory is the complete integration of new and existing experimental stations. The second part of the unit operations laboratory course at XXXXXXXXXX was integrated to model of bio-fuel production plant where student groups work on individual operations that make up a complete process. This full-plant view of the laboratory allows students, for the first time, to evaluate the effects of their decision on upstream and downstream plant operations. Furthermore, it also provides a common framework to promote active discussion and engagement amongst student groups. The transformation of the course included the development of completely new modules for fermentation of biomass and the modification of existing equipment and modules for the treatment, separation and extraction of product and waste streams. The new fermentation modules utilize internet-based remote monitoring technologies to track the development of fermentations while students are outside of the laboratory. Fully interconnected units now define a common goal of reducing costs and improving productivity and replace the original independent design concepts, such as cost analysis and environmental compliance, into the laboratory. The objective of the re-designed course is to provide a realistic structure that is congruent with what students will experience after graduation. The new laboratory structure is also designed to foster leadership, creative thinking, composure under uncertainty and the critical review of information. Furthermore, with the new structure, we also continue to meet the original learning objectives of instructing students on the basis of experimental planning and reporting.• Jimmy Crack Corn and I DO Care: Fluidized-Bed Drying of Cracked Corn Fluidized-bed fundamentals and technologies are often only briefly covered in undergraduate chemical engineering curricula. However, fluidized-bed reactors, fluidized-bed coating, and fluidized-bed drying play important parts in the chemical process industry. A unit operations laboratory experiment is described that consists of determining the fluidization characteristic and drying behavior of a bed of cracked corn. The concepts of minimum fluidization velocity and fluidized-bed expansion are introduced to the students, while application of Ergun’s equation to fixed-bed behavior is demonstrated. Statistical skills are reinforced as students are required to define the reproducibility of their data and to make statistically justified judgements as to whether or not the data that they generate is adequately described by models found in the literature. The drying portion of the experiment requires the application of an unsteady-state mass balance to the determination of the percentage of the water removed from the dry corn product. Details of the apparatus, experimental procedures, desired learning outcomes, and the mini-design project associated with this experiment will be described.• The Use of COMSOL Multiphysics Simulations to Enhance the Learning of Basic Concepts of Heat and Momentum Transfer In the chemical engineering curriculum, students are taught about the fundamentals of heat and momentum transfer. The teaching process involves classroom lectures and often corresponding undergraduate laboratory experiments. Another tool that can be used to reinforce the concepts introduced in the classroom and practiced in the lab is computer simulation. The benefits of using COMSOL are many: 1) it is designed to model heat, momentum, mass, etc. transfer; 2) ease of learning the software; 3) the ability to have either simple or complicated models; 4) quick simulation time; 5) and relative low cost. We have developed two systems that incorporate COMSOL simulations. In one lab, students perform a simple steady-state transient heat conduction experiment. This experimental data can used to estimate the thermal conductivity, k, and thermal diffusivity, a, of a material in the shape of slab. A COMSOL model can then be constructed with k and a as the inputs to model the transient heat transfer through the material. The students can make a direct comparison between their experimental findings and the COMSOL simulation. In another application, the students can use the Navier- Stokes equations to derive the parabolic velocity profile of liquid flowing through a narrow slit. Now the students can make a direct comparison between a theoretical prediction and a COMSOL simulation. We hope that introducing students to COMSOL will intrigue them to explore the power of the software, especially the built-in “Chemical Engineering” module.• Low Cost, Safe, Hands-On Reaction Experiments Denture cleaning tablets (Efferdent, Polident, drugstore generic) are both easily available and cheap. This simple chemical system can be used to illustrate several aspects of reactions and reaction engineering. Put a tablet in water and the citric acid and sodium bicarbonate react vigorously. Varying temperature demonstrates different reaction rates. Different ratios of tablet mass to water can be explored. A sensitive electronic scale (~$500) can be used to monitor mass changed as CO2 product is evolved and lost from the reaction container. This poster will illustrate the process and include example students work and anecdotal observations made by both the instructor and the students.• Experiments in Heat Transfer and Energy Efficiency Heating and boiling water using various methodologies has been used to bring home to students the concepts of energy balance and the First Law of Thermodynamics. Transient heating of water using hot plates, coffee makers, microwaves, and immersion heaters can illustrate the different efficiencies of the heating devices. This has been done using glassware, plastic cups, and styrofoam cups to illustrate the amount of energy required to heat the container. Using boiling water with these containers, students can see the different efficiencies of the devices. The continue energy does not change significantly in these experiments. The poster will show the process and have example student work and anecdotal observations provided both by the instructor and by the students.• Integrating Sustainability into the Unit Operations Laboratory More than ever, we need global citizens with the ingenuity to solve complex problems. We are faced with many urgent challenges: climate change, pollution, and the shortage of energy, food, and water. These problems require technical, social, ecological, economical, and political solutions. Engineering education sits at the core of this, as many industries and various engineering professional bodies have identified the “sustainability” as the top priority (Hesketh et al. 2004). In the field of chemical engineering education, the evolution of green chemistry and pollution prevention have led to dedicated courses such as green engineering and industrial ecology in the senior levels. However, in order to bring the concepts of sustainability into the basis of all engineering design and practice, “full integration of the sustainability concept into engineering curricula” (Glavič 2006) is required. Integrated frame work of sustainability in chemical engineering connecting the pathway from individual to global level have been described as the hierarchy in sustainability (Batterham 2006). This paper presents a case study on how sustainability was incorporated into the 3rd year unit operations laboratory course. There are two unit operations laboratory courses taken by 3rd year students where ten lab stations are available, including fluidized beds, fuel cell, heat exchanger, sedimentation, rotary viscometer, rotary filtration, air cyclone, pumps and valves, and thermocouple data logging. In addition, the class was split into groups (4 groups, 8-9 students/group) to work on one of the group projects. This was set under SEEDS (Social, ecological, economic, development studies - http://www.sustain.ubc.ca/seeds) with projects pre-set to work on UBC aquatic centre, UBC steam plant, UBC farm, and UBC composting facility. The UBC SEEDS program is “Western Canada’s first academic program that combines the energy and enthusiasm of students, the intellectual capacity of faculty, and the commitment and expertise of staff to integrate sustainability on campus” (http://www.sustain.ubc.ca/campus- sustainability/getting-involved/faculty-staff). Each group was responsible for contacting the client on campus to define the scope of the project, conducting research, proposing solutions, and reporting. The output of the group project was a report and a presentation where they stated the problem (defined with the client) and proposed a solution. The clients were invited to the presentation to participate in questioning and providing feedback. A section on “Reflections on UBC and Sustainability” in the final report emphasized their learning and understanding of where the university stands, and how their project can contribute to sustainability on campus. Hesketh et al., Int. J. Engng Ed., 20, 113-123, 2004. Glavic, Clean Techn Environ Policy, 8, 24–30, 2006. Batterham, Chem Engng Sci, 61, 4188 – 4193, 2006.• Downsizing Space and Equipment, But Not the Experience: Reinvigorating the Unit Operations Laboratory at XXXXXXXXXX The Chemical and Biomolecular Engineering Department at XXXXXXXXXX has recently completed a major renovation of our teaching laboratory. As with many departments across the country, we are space-limited and therefore could no longer maintain the old high-bay teaching facility. The renovation allowed us to create a space that was flexible enough to support current as well as any future experiments. The renovation also required us to redesign experimental set-ups which would fit in the new space. I will present our designs for both the space and our current experiments and show the results of our efforts. The Fall 2010 Unit Operations course was the first to be offered in the space. I will share impressions from the faculty and students participating in that course.• Intended Outcomes of a Unit Operations Laboratory Experience Graduates from an accredited ChE undergraduate program should enter the workforce with the ability to identify, understand, and solve the problems they encounter. Science, mathematics, design, and social sciences can be taught in a traditional classroom setting, while chemical process problem solving skills are best developed in a laboratory setting. For chemical engineers, the Unit Operations Laboratory is the ideal opportunity to develop this special skill set. Due to resource limitations, Unit Operations Laboratory courses are typically designed around available equipment. Experimental objectives are formulated based on equipment capabilities; students run an experiment following an accepted procedure; data are collected and analyzed; and a report is submitted for grading. An alternative to this “equipment-defined assignment” is to develop experimental objectives based on the program’s ABET Outcomes. An “Outcomes-based Assignment” encourages the students to explore the equipment’s possible range of operation to a) determine applicable theory and appropriate empirical relationships, b) develop an experimental strategy bounded by safe work practices and the equipment’s operating range, and c) develop a plan to minimize the effects ofexperimental error. Materials provided to the students at the start of the planning stageshould provide only enough information for the students to make these determinations.For example: piping, instrumentation and equipment specifications are provided alongwith a cover memorandum stating the specific experiment objectives. If the unitoperation of interest is one not typically introduced in a prerequisite course, thensuggested references might also be included. Equipment diagrams, operating procedures,MSDS’s, and determination of parameter space are left to the teams of students todiscover or develop. The Unit Operations Laboratory at XXXXXXXXXX has beendesigned and built to facilitate development of the ABET Outcomes-defined skill set. Theyear-long course sequence is split into a traditional Unit Operations Laboratory coursewhere the students operate five different unit operations experiments during the 14 weeksemester. The second semester builds on the skill set from the first semester and requiresthe students to work in “teams of teams” to operate each of our two pilot plant processesin a course called Plant Operations Laboratory. The theme of the second semester courseis Continuous Improvement in Chemical Manufacturing.XXXXXXXXXX’s Unit Operations Laboratory (semester 1) includes (17) unit ops, mostof which were designed and fabricated in-house. These units are of large enough scalethat industrial instrumentation is used for measuring flow, level, temperature, andpressure, thus exposing the students to the types of instrumentation they will encounterprofessionally. The large-scale equipment also forces the students to work as a team toaccomplish their experimental objectives. The laboratory safety program develops anawareness of safety in all actions within the lab environment and encourages the studentsto take ownership of the safety of others. The pre-laboratory work requires the team todivide the work into manageable tasks to explore a range of possibilities for problemdefinition, examination of the parameter space and development of a strategy for success.The laboratory proposal and final report helps prepare our students to write succinct,accurate, engineering reports. Finally, a requirement for two oral presentations in thefirst-semester Unit Operations Laboratory course develops professional oral presentationskills.The laboratory facilities for the Plant Operations course (semester 2) are the two pilotplants included in the Process Simulation and Control Center. The Solvent Recovery Unit(SRU) is a continuous distillation pilot plant that is operated in shifts without shuttingdown between transfer of responsibility between teams of students. The PolymerizationReaction Unit (PRU) is a 30-gallon batch reactor, complete with all supportingequipment to batch process polydimethylsiloxane. The SRU is a continuous processwhile the PRU is a batch process, so control, operation, and analysis of these processes isvery different. In both cases, the students are assigned to improve an imperfect process.In a seven week project, they research historical data to determine assignable causes forvariation that produced off-specification product, then develop a total solution toeliminate this type of event from occurring in the future. These capstone laboratory courses prepare students for a career in chemical manufacturing and are unique to the XXXXXXXXXX Chemical Engineering experience. The outcomes-based approach allows students to practice ABET skills while functioning as a Chemical Engineering Professional team to solve real-world problems.• A Simulated Biodiesel Pilot Plant in the Senior Chemical Engineering Unit Operations Laboratory at XXXXXXXXXX ChE XXX is our senior laboratory course at XXXXXXXXXX and it is one of the core courses for our Chemical Engineering curriculum. During the past few years, we have modified several existing unit operation equipment in the laboratory and integrated them into a simulated biodiesel pilot production facility. The approach includes the following unit operations used in the biodiesel production process. These pilot scale process equipments include: · Transesterification Reactor to produce Biodiesel fuel (FAMEs) from a triglyceride source (such as crude or waste vegetable oil). · Liquid-Liquid (Podbielniak) Extraction to remove impurities such as methanol and trace glycerol contained in the biodiesel product. · Distillation column to recover waste methanol from diluted water mixtures · Evaporation to concentrate glycerol byproduct · Microalgae photobioreactor for the conversion of glycerol byproduct of the transesterification reaction for the production of new triglyceride material to use in the transesterification process. In addition to the advantages of providing the students a clear view of the interconnectedness of these units within an integrated production process, this approach also allows the laboratory to became an invaluable teaching tool for various skills fundamental to our profession such as team work, time management, the importance of producing valid information in a timely manner for other groups or teams, and the necessity of working in a interdependent group environment to develop the specification and design of a large industrial scale facility based on the information gathered from actual pilot plant or laboratory environment. Additionally, the students are encouraged to produce by the end of the semester a single group report on the viability of the process integration and improvement for the entire plant.
Prudich, M. E., & Briedis, D., & Ofoli, R. Y., & Barat, R. B., & Loney, N. W., & P.E., A. P., & Elsass, M. J., & Wilkens, R. J., & Pozzo, D., & Pfaendtner, J., & Baratuci, W. B., & Henry, J., & Rogers, B. R., & Sandell, J. F., & Minerick, A. R., & Keith, J. M., & Duarte, H. A., & Caspary, D. W., & Nuttelman, C., & LaValle, P., & Ellis, N., & Mendez, S., & Biermans, A. (2011, June), Unit Operations Lab Bazaar Paper presented at 2011 ASEE Annual Conference & Exposition, Vancouver, BC. https://peer.asee.org/18372
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