Paper ID #34909

Integrating a Laboratory into a First-semester Introduction to ChemicalEngineering Course

Dr. Susan M. Stagg-Williams, The University of Kansas

Dr. Susan M Stagg-Williams is the Charles E. & Mary Jane Spahr Professor and Chair of Chemicaland Petroleum Engineering at the University of Kansas (KU), with a specialty in biomass conversion.She has worked closely with the KU Center for Teaching Excellence and been a champion for courseredesign across campus. Her primary focus has been on large freshman and sophomore classes. She is thefounder of the KU Biodiesel Initiative which provides opportunities for undergraduate students to applytheir engineering skills in practical applications while earning their degree. Dr. Stagg-Williams earnedher B.S. in Chemical Engineering from the University of Michigan in 1994 and her Ph.D. in ChemicalEngineering from the University of Oklahoma in 1999.

Dr. Molly McVey, The University of Kansas

Dr. Molly A. McVey is a post-doctoral teaching fellow at the University of Kansas School of Engineeringwhere she works with faculty to incorporate evidence-based and student-centered teaching methods, andto research the impacts of changes made to teaching on student learning and success. Dr. McVey earnedher Ph.D in Mechanical Engineering from the University of Kansas in 2012.

Mr. Andrew David Yancey, The University of Kansas

Andrew earned a B.S. in Chemistry from Baylor University in May 2019. Currently, he attends theUniversity of Kansas where he is pursuing a PhD in Chemical Engineering. His research focuses onselective separation of azeotropic refrigerant mixtures using porous materials.

Mr. Akash Anand, The University of KansasMr. Arthur A. Lee, The University of Kansas

PhD Candidate, Bioengineering Graduate Program

c©American Society for Engineering Education, 2021

Integrating a Laboratory into a First-Semester Introduction to Chemical Engineering Course

Abstract

The Introduction to Chemical Engineering course at the University of Kansas has traditionally been taught as a 2-credit hour, 1-semester course in the fall of the freshman year. In 2019, the course was redesigned to span both the fall and spring semesters and incorporate a hands-on laboratory experience each semester. The lab was structured to accommodate enrollments of up to 144 students, with each student attending four two-hour laboratory sessions during each semester. This paper is focused on the laboratory component of the fall semester course.

The primary goal of the fall semester laboratory was to expose students to chemical engineering concepts while providing opportunities to see chemical engineering processes from feedstock selection to products utilization. The focus of the laboratory was the production of biodiesel from vegetable oil with each laboratory period highlighting a different aspect of the process involved. The four laboratory sessions covered concepts including batch reaction, separation of products, purification of biodiesel using an ion exchange mechanism, and glycerin purification using distillation with emphasis on methanol recycling. Aspen modeling of the distillation process, and fuel property testing along with product utilization in a diesel generator was demonstrated. The students were able to see the integration of each experiment with respect to the overall engineering process and complete mass balances on individual processes and the complete process over the course of the semester. Additionally, fundamental chemical engineering topics including transport phenomena, thermodynamics, and reaction engineering were introduced when appropriate during experiments. Finally, for each laboratory session, the students saw a demonstration of larger-scale equipment for each process unit being studied.

Retention analysis of first-year students to the university and the major along with evaluations from the students in the sophomore year will be presented.

Introduction

The University of Kansas (KU) Chemical and Petroleum Engineering (C&PE) department has historically introduced students to the chemical engineering profession using a one semester, two credit hour “Introduction to the Profession” course. The course provided students information in three main areas: 1) an introduction to work done by professional chemical engineers, the resources available to help them be successful at KU, the curricular requirements and expectations of chemical engineering students, and possible career opportunities; 2) an introduction to engineering ethics, basic safety considerations, teamwork, and technical writing; and 3) an introduction to basic material and energy balances and fluid flow. This course was the only chemical engineering course the students took during the freshman year.

While teaching the first semester sophomore Material and Energy Balance course between 2009 and 2012, students often remarked that the freshman class was boring and that they still did not understand what chemical engineers did. Based on this feedback, a proposal was submitted in 2013 to the Kansas Soybean Commission called “Beyond the Book: Active Learning through Biodiesel (#ALT-B)” to develop a freshman course which would include a laboratory component centered around the production of biodiesel. Students would be exposed to all of the processes

and chemical engineering concepts related to biodiesel production including reactions, separations, fluid flow, heat and mass transfer, process control, thermodynamics, and material and energy balances. The goal was to introduce students to the fundamental concepts at a high level while providing an opportunity to see how the concepts are integrated while exploring in a hands-on laboratory. The production of biodiesel was selected because the University of Kansas has a Biodiesel Initiative which has a pilot scale process that converts used cooking oil into biodiesel and provides it to campus for various applications.

While the original grant proposed a laboratory related to biodiesel production, the department ultimately decided to have two courses each with a laboratory component to maintain a connection with students throughout the first year. The department’s Curriculum Committee discussed that students in the chemical engineering program did not have any chemical engineering specific courses in the spring semester of their freshman year. The perception from the faculty was that the loss in contact between the chemical engineering students and the department between the fall of freshman year and the fall of sophomore year negatively impacted retention. Literature has shown the multitude of factors affecting student retention in engineering include classroom and academic climate, grades and conceptual understanding, self-efficacy and self-confidence, high school preparation, interests and career goals, race and gender, poor teaching and advising, curriculum difficulty, and a lack of belonging [1, 2]. In a multi-year study at a single institution, the lack of belonging was the most significant factor reported by students that left [2]. At the course level, active and cooperative learning have repeatedly shown to be important factors in student success and retention. For example, increasing course structure, increased transparency, and active/cooperative learning have been shown to increase success for all students [3], but particularly for students from under-represented groups [4, 5]. Additionally, hands-on projects in a first year engineering program have been shown to improve retention [6, 7]. Therefore, this redesign focused on two factors known to be important for student retention: improving a feeling of belonging [2] by providing continuity of contact with the department and content and by including hands-on, active learning in a first year course [6, 7].

While the content development of the biodiesel-based laboratory was completed in 2015, several other factors influenced the timing of the first offering of the course. The School of Engineering opened a new building in fall of 2015 and the senior chemical engineering laboratory courses for the C&PE Department moved to the new building. While this opened up some space, the laboratory was still being used by the petroleum engineering courses. In the fall of 2018, these courses moved into new laboratory space in the Earth, Energy & Environment Center (EEEC) which allowed for the freshman laboratory to have a home. The department and School of Engineering Senate approved the proposal for the change in structure and the addition of the spring semester course. Also, during that time, Frank and Stephanie Tsuru made a generous donation to the department to support the renovation of the laboratory space and the purchase of equipment and supplies for the course.

The new introductory courses were taught for the first time in the 2019-2020 academic year. The fall 2019 course was taught as originally envisioned; however, the spring 2020 course was interrupted due to COVID-19. This paper will focus on the first semester course as taught in fall 2019, providing an overview of the course structure and the experiments involved in the laboratory component. The end of the article will discuss changes that were made in the fall of 2020 because of COVID-19 restrictions.

Structure of the New Courses

The structure of the fall and spring courses is similar. All students attend one 50-minute lecture once per week. The fall lectures focus on an introduction to work done by professional engineers, the resources available to help them be successful at KU, the curricular requirements and expectations of chemical engineering students, and possible career opportunities with some technical content related to the laboratory experiments and an introduction to engineering ethics. Guest speakers from the School of Engineering Career Center and Academic Student Services were eager to help present some of this content. Table 1 shows the calendar for the fall 2019 offering of the course. Items marked in red indicate lectures that focused on technical content.

The spring semester lectures provide an additional discussion of ethics and introduce process safety and basic material and energy balance calculations. In-class problems and quizzes, homework assignments, and reflections on the guest speakers account for approximately 30% of the grade.

Reviews of the lectures from the fall 2019 course suggested that students wanted to see more of the “day in the life of a chemical engineer.” In the fall of 2020, alumni presentations from a variety of industries were added to the lecture schedule. Alumni talked about their job and industry, the career path, provided advice on life during college and after the degree. This change was easy to implement because the lectures were operating in a virtual format due to COVID-19 restrictions on the number of in-person students allowed. While the students really responded positively to the addition of alumni speakers, even in a virtual format, reviews asked for a balance between alumni speakers, resource information, and technical content.

In addition to the lecture component, each student attends a laboratory session four times over the course of each semester. The laboratory sessions are 1 hour and 50 minutes, and three laboratory sessions are offered on Thursday (8 AM – 9:50 AM, 11 AM – 12:50 PM, and 2 PM – 3:50 PM). Each laboratory session has four groups with up to four people in a group for a maximum of 16 students participating in each laboratory time. Table 2 shows how a cohort schedule was established to be able to accommodate up to 144 students in the laboratory. Higher enrollments could be handled by offering the lab on more than one day a week. For each laboratory session, the students are expected to complete a pre-lab assignment, participate in laboratory activities, and then complete a post-lab assignment with their respective group members. The laboratory component of the class comprises approximately 35% of the grade in the course.

Table 1 – Lecture schedule for the fall 2019 Introduction to Chemical Engineering I course. Items in red indicate technical content.

1 Introduction/Syllabus/What is Chemical Engineering

2 School Resources, Career Services

3 Chemical Engineering Basics / PFD

4 Introduction to Biodiesel Reaction and Calculations

5 C&PE Curriculum - Study Abroad

6 Introduction to Mass Transfer - Separations - Diffusion

7 C&PE Faculty Panel

8 no class fall break

9 Ethics - Safety

10 Introduction to Distillation

11 Introduction to Aspen

12 Introduction to VLE - Ethics Scenario Discussion

13 C&PE Student Panel

14 No class Work on Project

15 Design Exercise

16 Evaluations/Class Wrap-up

Final Project - Poster Presentations

Class Lecture Topic

The final exam for the fall semester course is replaced with a semester project. The goal of the project is to allow students to explore and apply their own passion for chemical engineering. Students pick a product/process that they are passionate about and create a poster exploring the details of the product/process. Students are required to include the discussion detailed below in their poster:

1) Description of the product/process with a process flow diagram (PFD) showing the major units involved in the product/process.

2) History of the product/process discussing the major advances or milestones achieved. 3) Economic information about the product/process including units produced per year and

the value of the industry. Discuss the major companies that work in this industry.

Table 2 – Laboratory cohort schedule for the fall 2019 Introduction to Chemical Engineering I course. Each laboratory session could accommodate up to 16 students for a total enrollment capacity of 144 students.

29-Aug

5-Sep

12-Sep

19-Sep A A A

26-Sep B B B

3-Oct C C C

10-Oct A A A

17-Oct B B B

24-Oct C C C

31-Oct A A A

7-Nov B B B

14-Nov C C C

21-Nov A A A

28-Nov

5-Dec B B B

12-Dec C C C

Safety

1

2

3

4

Separation/Purification

Distillation/ Methanol recovery recycle

Product analysis and utilizationNo Lab

Lab Topic

No Lab Safety Quizzes due Sept 12th

Biodiesel Reaction

Afternoon CohortLab Week Date Morning

CohortMidday Cohort

4) Discuss the chemical engineering concepts that have been introduced in class that are present in the product/process and those concepts that are new.

5) Discuss the role of a chemical engineer in this industry, the other professions they would collaborate with, and the skills required to be successful.

6) Discuss what is appealing about the product/process. Students are required to present their poster at the end of the semester in a poster session that is held in the main atrium of the KU School of Engineering complex. Groups of 25 – 30 students present their posters for 30 minutes and each student is required to evaluate 6 posters of their peers. The poster session is advertised and open for anyone to attend. The semester project accounts for approximately 35% of the course grade. Details of the Fall Semester Laboratory Component

The design of the fall semester laboratory course started with a grant from the Kansas Soybean Commission titled Beyond the Book: Active Learning through Biodiesel (#ALT-B). The specific goals of adding the laboratory were to:

1) Expose each student to the integrated nature of chemical engineering concepts by having them work on laboratories that were integrated from feedstock to product.

2) Increase material and concept retention so that students would remember the laboratory experience when presented with theoretical material and concepts in future courses.

3) Increase retention to the sophomore year. 4) Increase opportunities for peer mentoring.

The concept of the grant was to use the processes involved in the production of biodiesel as a

vehicle to expose students to all the facets and concepts of chemical engineering throughout a single semester course. Each laboratory session is designed to build upon previous sessions and discuss the processes involved from feedstock to final products. During each laboratory session, chemical engineering concepts are discussed, and students have the opportunity to visualize these concepts.

The lab is staffed with Graduate Teaching Assistants (GTAs) and Undergraduate Teaching Fellows (UGTFs). The UGTF role is unique from a GTA role in that they are only responsible for in-class support of active and/or hands-on learning, and not any grading or course development. UGTFs are students who have recently been successful in the course (or a similar course), so are near-peers to the students in the class. The use of UGTFs has been shown to lead to improved student outcomes [8] and they are specifically utilized in this class to provide peer mentoring to the freshmen. In addition, having the UGTFs in the class and laboratory sessions explaining chemical engineering concepts helps with material retention for the UGTFs. Each laboratory group is assigned either a GTA or a UGTF to work closely with them during the laboratory session providing a small student to instructor ratio. The groups assigned to a given GTA or UGTF are rotated so that each group works with four different GTAs/UGTFs over the semester.

The details of each laboratory session and the integrated concepts are discussed below.

Week 1 – Biodiesel Production

The first laboratory session is focused on the transesterification reaction to produce biodiesel (a mixture of fatty acid methyl esters (FAMEs)) from soybean oil. The mechanism of triglyceride transesterification with methanol is shown below.

Figure 1 – Mechanism of triglyceride transesterification with methanol producing glycerol

and fatty acid methyl esters (FAMEs). Transesterification reactions can be carried out in two pathways, either catalytic (using acid

or base catalyst) or non-catalytic (high temperature and pressure). For this laboratory session, the transesterification reaction is carried out in the presence of sodium methoxide (base) and the products are glycerol and a mixture of FAMEs (biodiesel). During this laboratory session, students are presented with the concepts of batch and continuous reactions, reaction stoichiometry, use of excess reactants, equilibrium, unsteady state and steady state processes, material balances, process control variables with respect to the reaction temperature, mixing, mass transfer, heat transfer, and condensers.

A picture of the reactor set-up is shown in Figure 2. The reactor consists of a one-liter glass reactor (Ace Glass approximately $6,000) with an external heater and overhead stirrer. The reaction temperature is monitored using a thermocouple immersed in the reactor and is controlled using a temperature controller. Mixing is provided from an overhead stirrer equipped with a controller for students to set the desired speed. The reactor is also equipped with a condenser, an addition funnel for adding materials during the experiment, and a bottom drain to collect the products without disassembling the reactor. Each group had their own hood which housed the reactor setup.

The transesterification reaction is conducted at 65°C for 40 minutes with 350g of soybean oil

(purchased from a local store), 1 wt% sodium methoxide catalyst, and a 6:1 molar ratio of methanol to oil. The oil is preheated in the reactor to the reaction temperature and then the methanol and catalyst are added using the addition funnel. When the reaction time is complete, the reaction contents can be drained from the bottom of the reactor into a beaker and poured into a 500-1000mL separatory funnel which is labeled with the cohort and group information. Separation of the biodiesel and glycerin products begins immediately, with the glycerin product at the bottom of the separatory funnel with the biodiesel on top. Figure 3 shows an example of the products after separation. The products remain in the separatory funnel until the students come in for the next laboratory session.

Figure 2 – Reactor apparatus (Ace Glass) including a 1L glass reactor with external heater, temperature controller with thermocouple, overhead stirrer, condenser and addition funnel.

The concepts that are discussed during this laboratory session include:

• Counter-current and co-current flow and heat exchangers while the students are connecting the lines to the condenser.

• Stoichiometry, unit conversions, equilibrium, and excess reactants while the students calculate the amount of catalyst to add to the reactor. Since the catalyst is in a methanol solution, they must account for this methanol when determining the additional amount of pure methanol to add to the reactor to make a 6:1 molar ratio. Table 3 shows the table of the calculations the students work with for the lab.

• Exothermic versus endothermic reactions, runaway reactions, and the importance of process control, especially since the temperature may overshoot the set point when heating

• Mass transfer in the reactor and the impact of stirring on the process. • Fundamental driving forces in chemical engineering as students learn that: 1) pressure

makes fluid flow, 2) temperature makes heat flow, and 3) concentration makes mass flow.

• Different methods of heating the reactor. During the reaction the students are presented with a 20L jacketed glass reactor and discuss the difference between using a jacketed reactor versus a reactor with a heating mantle.

• Batch versus continuous processes. The reaction in the lab is a batch reaction, and the students are challenged to design a steady state process. Students are asked to consider that every move they make in the lab represents pipes and pumps in a chemical plant.

Figure 3 – Separatory funnels containing products from the transesterification of vegetable oil using methanol and sodium methoxide. The top layer is biodiesel and the bottom layer is glycerin. The color of the glycerin product changes with the age of the soybean oil.

Finally, students are asked to anticipate the next steps that would be required in the process

to be able to produce and sell a pure biodiesel product. While the focus of this lab is on reactions and the chemical industry, it is important that the students see how these concepts can also be related to the human body. During the discussion students are reminded that many of the concepts that they will see are related to medical or bio focused careers and that while scale may be different, the principles are the same.

For the post lab, students are required to calculate the material balances for each part of the process and discuss any differences or lack of material balance closure. Week 2 – Separation and Purification of Biodiesel

The focus of the second laboratory session is the separation and purification of the biodiesel product. The main concepts discussed in this laboratory session are ion exchange, purity, recovery, density, and immiscible fluids. Two ion exchange experiments are performed. The first experiment provides visual and analytical proof of ion exchange. The second experiment purifies the biodiesel product.

The experiments using the biodiesel and glycerin products in the separatory funnel from the first laboratory session. Students are tasked with recovering as much glycerin and biodiesel as possible from the separatory funnel. The glycerin is drained into a jar and kept for later use. The interface layer containing both glycerin and biodiesel was then drained into a beaker. The goal is to remove only a small amount of biodiesel but to make sure that no glycerin is visible in the separatory funnel. The biodiesel product is left to sit in the funnel while the visual ion exchange experiment is conducted.

Table 3 – Calculation table that students create to determine the amount of methanol and catalyst solution to add to the reactor based on the amount of oil, weight % of catalyst and the molar ratio of methanol : oil. Highlighted areas are user inputs, bold values represent material added to the reactor. Calculations for Determining Methanol and Catalyst RequirementsMass of oil added 350Catalyst loading relative to oil 1.00Mass of catalyst required 3.50

Mass of 25 wt% catalyst solution required 14.00Mass of methanol in catalyst solution 10.50

Molecular weight of oil 872.3 grams/molMoles of oil added 0.401Methanol required (6:1 methanol:oil molar ratio) 2.407Total mass of methanol required 77.13

66.63

**You need to subtract the amount of methanol contained in the catalyst solution from this value

moles Methanolgrams of methanol required**

Total pure methanol to be added

grams of oil

grams of methanol added in addition to catalyst solution

wt% relative to oil

grams of methanol in catalyst solutiongrams of catalyst solution required

grams of sodium methoxide

moles of oil

The ion exchange columns used in this experiment are shown in Figure 4. The students check the calibration of the pH meter using 10.0, 7.0, and 4.0 buffer solutions and recalibrate if necessary. For the color experiment, Amberlite® IR-120(H) ion exchange resin is used. The pH of DI water is measured before and after washing the resin in the tower. After washing the resin, the pH of 200 mL of 0.1 N KCl is measured. Students are asked to predict what color the solution will turn if methyl purple indicator is added to the solution and then they test their hypothesis using 3000 µL of methyl purple indicator added to the 0.1 N KCl. The KCl solution

Figure 4 – Glass column used for ion- exchange experiment. Column was fabricated by James Hodgson at Kansas State University.

with indicator is then poured into the ion exchange column and the color change is immediately observed. Measuring the pH of the effluent from the column also shows a significant drop in pH.

After the completion of the color exchange experiment, the biodiesel purification can be completed using a second column and 5.0 g of DudaLite DW-R10 ion exchange resin. The biodiesel that has been sitting in the separatory funnel should be free of glycerin and ready for the experiment. It is important to make sure that the biodiesel in the separatory funnel is free from residual glycerin before draining into the beaker. The presence of sodium in the biodiesel before purification can be observed using a small sample of the biodiesel and a phenolphthalein indicator solution. The biodiesel can then be poured into the ion exchange column and drains using gravity. A small amount of resin is used to intentionally reduce but not eliminate the amount of sodium in the biodiesel with a single pass. The presence of sodium in the effluent can again be tested with the indicator solution. Students are asked to design a system to remove the sodium in the biodiesel to acceptable levels and allowed to explore different options. Finally, the biodiesel is purified by pumping it through a two-column set-up. Figure 5 shows a sample of biodiesel samples at various stages of purification.

The concepts that are discussed during this laboratory session include:

• Mass transfer at the interface between the immiscible fluids and the concept of boundary

layers. The students are asked to think about the tradeoff between purity and recovery and what happens if you recover 100% of the biodiesel but it does not meet the ASTM standards.

• Ion exchange resins and the difference between cation and anion exchange resins. • Diffusion and mass transfer when the indicator is added to water and how stirring is

necessary to speed up the process of making the solution homogeneous.

Figure 5 – Samples of biodiesel and phenolphthalein indicator solution after various stages of purification.

• Resin function and how impurities may impact the performance. During the experiment, some indicator adsorbs on the resin. The color gradient in the bed shows the concept of a concentration profile or wave front in the bed and how the top of the bed will be spent before the bottom of the bed.

• Micropipettes. The indicator is added using a micropipette and students are taught the proper technique to use a micropipette.

• Continuous process monitoring. Students are asked why, unlike the color experiment, the indicator cannot be added to the biodiesel and discuss how sampling can be used to monitor a process.

• Process design with columns. Using multiple columns or multiple passes through the column, lead and lag columns, column regeneration and the factors that would go into making design decisions are discussed.

For the post lab the students complete the material balance calculations and are asked to

discuss the advantages and disadvantages of a dry wash (ion exchange) versus a water wash system for biodiesel purification. Week 3 – Methanol Recovery via Distillation

In the third laboratory session, the goal is to use distillation to recover the excess methanol from the reaction that is in the glycerin product. During this lab the concepts of distillation, vapor liquid equilibrium, reflux, and the different parts of a distillation column are discussed. In addition, students are also exposed to the concept of heat integration in a plant and revisit the balance between purity and recovery.

Figure 6 shows the distillation apparatus that is used in this experiment. A mineral bath on a hot plate is used to heat the round bottom flask. A thermocouple in the mineral oil is connected to the hot plate which controls the temperature. The mineral oil bath is set prior to the students coming into the laboratory to reduce the time necessary for the distillation to begin. After adding the glycerin and boiling chips to the round bottom flask, the temperature is increased so that the contents in the flask are close to 100°C. The temperature at the top of the column is monitored during the process and the distillation is complete when the temperature decreases.

The concepts that are discussed during this laboratory session include:

• Different methods of heating and process control. Students have now used a heating

mantle and mineral bath to heat different processes and the difference in the control can be discussed.

• Reflux, vapor liquid equilibrium, and the basic theory of distillation. While the distillation is occurring students can monitor the temperature at the top of the column and discuss how the temperature is related to what is happening in the column.

• Packed towers versus trayed towers. The students are shown different examples of packing and packed towers including structure and unstructured packing.

• The importance of the methanol purity for recycling. Students can use a hydrometer to measure the specific gravity of methanol/water mixtures and discuss the concept of recycle and purity.

Finally, students are presented with the equipment to assemble a distillation apparatus with a

reboiler, column and trays, reflux condenser, temperature monitor, and condenser. The distillation apparatus is a moonshine still (Mile High Distilling) and the students have the freedom to choose how many trays to install while seeing how to use gaskets and clamps during the assembly. An example of the final assembled apparatus is shown in Figure 7.

Figure 6 – Distillation apparatus used for recovering methanol from the glycerin product.

For the post lab the students think about the concept of recycle and are asked to calculate the economic impact of recycling the methanol. The students were also required to do a simple ASPEN model of the distillation process and show that the recovery and temperatures predicted by ASPEN were very close to the values measured in the laboratory. One class lecture was

Figure 7 – Distillation apparatus with trays that can be assembled by students.

devoted to showing the students how to use ASPEN and video tutorials were provided to the students [9]. Week 4 – Soap Production and Product Utilization

The focus of the final week of laboratory sessions is to analyze and utilize the products. The biodiesel product can be tested and used as a fuel and the purified glycerin can be used in the saponification reaction to make soap. During this lab the concepts of cold weather properties, biodiesel blends, and sustainability are discussed.

Using a beaker, magnetic stirrer and hotplate, the purified glycerin can be saponified to produce soap. Sodium hydroxide, sodium lactate, water, and stearic acid are used in the reaction. The amount of each component depends on the glycerin and the amount of residual sodium from the biodiesel reaction. The reaction is usually complete in less than 10 minutes and can be determined when the mixture starts to become viscous. The mixture can be poured into silicone ice cube molds and allowed to cure. The pH will likely be too basic to use initially, but over time the soap will cure, and the pH will decrease to less than 10 allowing the students to use their soap.

A biodiesel blend analyzer (InfraCal 2 – Spectro Scientific) is used to test the percentage of biodiesel in a biodiesel blending with diesel. The pure biodiesel (B100) can be blended with diesel to make a blend of 20% biodiesel and 80% diesel (B20) and the accuracy of the biodiesel blends can be monitored using the analyzer. In addition to testing the blend percentage, the cloud point of the pure biodiesel (B100) and biodiesel blends is observed using a chiller and small samples of the fuel in GC vials. Depending on the oil feedstock, the chiller temperature can be adjusted (usually less than 0°C), to ensure that small samples of biodiesel solidify. The physical transformation of the biodiesel back to liquid can be easily observed by holding the GC vial at room temperature.

In the final part of the laboratory session, students tour the KU Biodiesel Initiative production facility which uses 40-gallon reactors to convert used cooking oil collected from campus into biodiesel. Students see all the processes from the semester at larger scale. The biodiesel produced over the course of the semester is used in a diesel generator. The generator can be used to power many devices. One example is a microwave that can be used to pop popcorn which can be given to the students as a snack. Using the diesel generator allows students to see their product being used in a real application. At the end of the semester, each student can take home a small bar of soap.

The concepts that are discussed during this laboratory session include:

• Cold weather properties and ASTM property testing of fuels. The impact of cold weather properties on the utilization of the biodiesel, ways to improve cold weather properties, and the importance of ASTM testing of fuel properties is discussed.

• Biodiesel blends. How the blend analyzer works using infrared spectroscopy, the limitations of the instrument in detecting the quality of the biodiesel, how blending impacts fuel properties, and the current limits on fuel blends in engines.

• The saponification reaction and the impact of additives on the properties of soap. Additives and the chemistry that results in properties such as lather, hardness, and clarity can be discussed.

• Generators and how generators produce power.

For the post lab, the students discussed the role of stearic acid and sodium lactate in the

saponification reaction and provided a reflection on the labs for the semester. Evaluation

To determine the impact of the course on student retention, both retention to the spring semester and retention to the sophomore year were evaluated. The retention to the spring semester was calculated based on enrollment in the “Introduction to Chemical Engineering II” course. The freshman courses are not required for the degree, thus enrollment in both introduction courses is recommended but considered optional. For this reason, retention numbers calculated using enrollment in the freshman courses might underpredict retention in the event that a student opted out of the course but remained in the chemical engineering program. Retention to the sophomore year was based on enrollment in the required fall semester sophomore “Material and Energy Balances” course.

The initial evaluation of the retention data shows that 80% of the students who took the redesigned first semester course in fall 2019 continued to the second semester freshman course in spring 2020. The retention of students to the sophomore year (fall 2020) that were enrolled in the first semester introductory course in the fall of 2019 was 65%. This retention to the sophomore year is slightly higher than the retention (ranged from 51.7% - 63.1%) in the previous 3 years.

One challenging factor in evaluating the impact of the new course on retention is the inability to decouple the impact of the redesigned class and the impact of COVID-19. It is likely that changes implemented by KU in response to COVID-19 negatively impacted the retention of students to the sophomore year. Several of the students that did not retain to the sophomore year did not switch majors but are not enrolled at the University of Kansas. It is difficult to determine if those students did not retain because of the major or because of the pandemic. Thus, while we can conclude that the retention increased, we cannot state the degree to which the redesigned course independently impacted retention.

Student evaluations of the course were overwhelmingly positive and included comments such as:

• “Thank you so much for allowing us to engage in real content!” • “I thought this course was very helpful in introducing me to the profession of Chemical

Engineering. I especially liked the lab portion of the class. It gave me a hands–on experience with chemical engineering and made me more certain about my choice of studying chemical engineering.”

• “The labs were hands–on and made me think about solutions and problems; I liked that a lot. It was interesting to have a lab that was dependent on the previous lab, making it continuously. Having it formatted like this helped sparked my curiosity. Overall, the class made me want to be a chemical engineer even more!”

• “I like how we learned about different things in each class (separation, distillation, etc.) that were all connected to each other in the end on the PFDs. I definitely came to understand how a PFD works! I also liked how labs were only four times a semester and they all built upon each other.”

Another goal of the course was to increase material retention so that students would remember the lab experience when presented with theoretical material in future courses. To determine if this goal had been achieved, students that had completed the course in the fall of 2019 were surveyed in the fall 2020 sophomore course. Students that had taken the redesigned course were asked if there were times during the sophomore year that they heard something or learned something that made them think of an experience in the redesigned introduction course. Of the students that responded to the survey, 45 stated that they had taken the redesigned course. Of those 45, 43 (93.2%) said that they had thought about the redesigned course at some time during the sophomore year class. Some students responded as to what they remembered and those are included below:

• Distillation • Txy Pxy diagrams (mentioned twice) • material balances; and the in and outs of long wordy equations • General material balances, types of systems, conversions, and many of the first steps of

our 211( sophomore) problems involve the basics we learned in 111 (the introduction class)

• How to put data given into an equation and conversions mostly • we did some MB tables last year • A lot of the word problems have similar setups to CPE 111 (the introduction class). The

drawing diagrams part was very helpful for that. Changes in Fall 2020 due to COVID-19

When the course was offered for the second time in the fall of 2020, several major changes were necessary because of restrictions in place due to COVID-19.

1) All lectures were held synchronously online. Enrollment in the course exceeded the COVID-19 room capacity and so the lectures were moved to an online format. The technical lectures for each lab were also moved to an online format and the open lecture days were filled with alumni speakers. Students appreciated the alumni guest speakers but asked to have fewer speakers and more technical content. The alumni speakers will be balanced with technical content and school resources in future offerings.

2) The laboratory capacity was reduced to 9 students which increased the number of cohorts from 3 to 4. To accommodate all the students in the laboratory, each student only attended 3 laboratory sessions. In addition to safety goggles, gloves, and lab coats, students were required to wear face masks and face shields. All the experiments described above were completed except for the saponification reaction. Also, it was not possible to do ASPEN modeling because of access to the software. The reduced laboratory sessions will not be maintained in future offerings as it is desired to give the students as many opportunities to be in the laboratory as possible. While students missed the extra day in the laboratory, they appreciated attending an in-person laboratory.

3) Due to the restrictions with large in-person gatherings, the final exam poster session could not be held. Thus, instead of posters, students produced videos about their product/process and posted the videos for the class to watch. Students were still required to comment on the videos for 6 peers, and the final exam time was used for group

discussion of the video topics. While the videos were outstanding and creative, the poster session will be used in future offerings due to the public nature of the poster session and the energy created around the event.

Conclusions

A first semester introduction to chemical engineering course was successfully redesigned to incorporate a laboratory component. The laboratory sessions followed the production of biodiesel from the feedstock through the utilization of the products and each experiment was integrated with the previous experiments. Students were exposed to the integrated concepts in chemical engineering and various scales of processes and equipment. Retention to the second semester of the freshmen year and to the sophomore year were positively impacted. Material retention in the subsequent year was also high with 93.2% of students recalling experiences from the redesigned course in a subsequent course. The Introduction to Chemical Engineering course with the integrated laboratory was successfully modified to handle restrictions due to COVID-19 and still allow for an in-person laboratory component.

Acknowledgments

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