Unit Operations, published by a team of Michigan Chemical Engineering faculty led by Professor George Granger (G.G.) Brown (photo on left) in 1950, revolutionized chemical engineering curricula from the previous emphasis on specific industries. Our senior laboratory course was revamped to this new approach. In the 1980s our ChE 460 lab received a major upgrade. Alumnus Pablo LaValle, with the assistance of lab technician Don Trombley, built five new experimental stations and added computer based data acquisition and control to all the equipment. (Photo below)
Under Professor Rane Curl the ChE 460 curriculum evolved in the mid-1980s, into a simulated industrial environment, known as “G.G. Brown Industries, Inc.” with Professor Curl as CEO and graduate student instructors (GSIs) as plant supervisors. Students took on the role of engineers, characterizing and optimizing unit operations in each of the three divisions, separations, reaction engineering and controls.
LaValle worked under the direction of Professor Curl, to increase the safety and reliability of the equipment and to modify it to accommodate new projects. The large distillation column was replaced with a laboratory-size packed-bed distillation column to characterize mass-transfer coefficients in random packing and to optimize distillation operations using a methanol/water system. The long-tube vertical evaporator was replaced with a double-effect evaporator designed and constructed by chemical engineering staff and used today to evaluate multiple-effect evaporation with water/glycerol system. A reaction cell was also added.
More recently, Professor Henry Wang has revamped the lab to simulate the unit operations required to generate an ASTM grade biodiesel product, with an emphasis on process integration with product recovery and reprocessing. This approach integrates most of the previously isolated unit operations in the laboratory into a “virtual” process where the inputs and outputs of each unit operation are intimately related. Students are encouraged to understand the entire process and grasp the interconnectedness of all the processing streams. Students address the need to meet the product quality and specifications, and minimize waste generation. They also identify technical problems, generate possible solutions, and evaluate the economic consequences of these solutions.
A memo introduces students to a proposed biodiesel production scheme developed by the United States Department of Agriculture (USDA) (Haas et al)1, and charges them with improving this process to minimize waste by proposing ways to recover, reuse, or recycle the byproduct streams. Students use information obtained through experimentation and data analysis to evaluate each of the proposed improved unit operations and scale them up to meet the desired output.
Students (like those shown using the photobioreactor at left) must keep an eye on the “big picture” so they know what to achieve in each task and how this fits in with the overall improvement of the biodiesel process. During the first rotation, teams of three students use the laboratory to characterize the process or equipment for the assignment. For example, establishing reaction rates as function of catalyst concentration and reactor operating parameters; or measuring mass transfer characteristics of a proposed packing to be used in the plant distillation operation. In some cases, simple Design of Experiment (DOE) concepts are encouraged in the experimental plan. For the second rotation new teams of students develop models of their assigned operation using simulation packages or spreadsheets to simulate various operation conditions encountered in the proposed plant. Concepts of “sustainability” through recycling and waste minimization are encouraged throughout the semester as the students evaluate the use of the process equipment and test various operating conditions. During the final rotation, student teams are encouraged to interact with each other as they pull all the unit operations together to produce an overall process flow sheet for the entire process. Students must not only focus on their particular unit operation but also need to consider how the output of their processing step may affect the process downstream, and how the processing conditions of the upstream process step would affect their performance.
This approach has enhanced the academic experience for our students and better prepares them for the experiences they will encounter as practicing engineers. Wang, LaValle, and Trombley continue the tradition of teaching excellence established by Curl and Brown before them.
Article from the 2011 Chemical Engineering Newsletter
1 A process model to estimate biodiesel production costs; Michael J. Haas *, Andrew J. McAloon, Winnie C. Yee, Thomas A. Foglia; US Department of Agriculture, Agricultural Research Service, (ERRC,1).
