Course: CBE250
Instructor: Link
F 2015

Description of Course Goals and Curriculum

The goal of this course is to teach the theory and role of separation techniques in modern chemical and biological engineering. Main topics will include equilibrium vs. rate-driven processes, distillation processes and the McCabe Thiele Diagram, and the effects of thermodynamic non-idealities when describing separation processes; the final portion of the course concentrates on biological separation processes and some introductory biochemistry. This course is very sequentially organized: it goes through five types of separation processes – e.g. membranes or heat-driven separation – followed by a shorter unit on biological separations. There is a heavy emphasis on distillation and distillation-like processes, given its importance in chemical engineering. There is one midterm (closed book, closed notes), and one final exam (open book, but no notes). There are ten problem sets, with one problem set issued over the winter break. The challenge of this course comes from the breadth of topics covered, and problem sets and lectures become key to a student’s learning. While thermodynamics is also useful to CBE 250, Prof. Link thankfully covers most necessary thermodynamics concepts in lecture rather than assuming students’ knowledge. A helpful strategy is to take notes on the problem sets themselves – for example, which unknowns are commonly targeted for this type of question – as the midterm and final exam are very much within the boundaries of knowledge given to the student. In fact, the challenge with the midterm, above all, is TIME pressure, while the difficulty with the final exam is the sheer breadth of material. A final point about this class revolves around its use of Piazza. Professor Link prefers Piazza to blackboard, and all necessary materials will be posted there: homeworks, lecture notes, syllabus, homework solutions, previous exams, etc. On the question board, where students can post questions about the problem sets or exam solutions, both the TAs and Professor Link will answer questions. It is important to note that they do so quickly and thoroughly, which demonstrates the staff’s – particularly Professor Link’s – dedication to the course.

Learning From Classroom Instruction

There are 5 main aspects to the course: lectures, problem sets, office hours, reading, and exams. Regarding lectures, it is critical to attend to learn the material: yes, even the Friday lectures at 9AM. It is worth mention that Professor Link is genuinely devoted to teaching his students. He expects everyone to show up for his lectures – yes, even the 9AM on Fridays – and also expects students to show for his office hours. Remember that he appreciates those who are truly dedicated to learning and grasping the material, so if you ask questions in class, show improvement on the problem sets, and come to office hours (for both TAs and the professor’s), then it will translate in the final exam. The lectures, in addition to teaching you the concepts, will provide the proper equations to solve the homework. For our year, he tried writing lecture notes via a tablet and posting them online; it is unclear whether Link will do something similar in the future, or simply write notes on the chalkboard as in previous years. Though one can rely on Link’s posted notes, taking your own notes will help. The problem sets lie at the heart of the course. They essentially teach you how the equations you’ve been taught are used, and why the concepts presented are relevant. The problem sets directly line up with the concepts learned in class; for example, if you’ve been taught about adsorption and stripping in lecture, the homework will focus on that. While the problem sets start off slightly basic, the student should know that they become increasingly difficult – particularly the mass transfer and membrane problem sets – while the biology-based homeworks are particularly long as well. The office hours become very useful to solve the problem sets. It is best to attempt the problems by yourself, and then head to office hours where the TAs will help. Professor Link also holds office hours, and even tries to hold them at a time that is helpful to students. As mentioned, he expects students to show to office hours, and is dedicated to teaching the material. Finally, this is one of the rare engineering classes where the textbook will be helpful, particularly the biology portion of the class. Though the Seader textbook itself can be a bit dense, skimming the textbook “critical readings” portion will be helpful to solve the homeworks. An effective strategy is to skim the readings while concentrating on the equations and the examples.

Learning For and From Assignments

As mentioned, the midterm and final exam are very much in line with the homework problems given in class. The main function of the problem sets of the course is to introduce the application of the equations and concepts learned in lecture; the main point of the assessments is to test whether these basic concepts have been grasped. Very often, the examples shown in lecture can be used as a template to help solve some of the homework problems, which is another great reason to attend lecture. Furthermore, the homework problems –particularly for topics 5, 6, and 7 in Seader and 8, 9, and 10 in Harrison – require you to look for the relevant equations in the textbook. Note that many of these equations will contain either constants that depend on certain conditions of the phenomena (like, say, a coefficient of sorts), or contain variables that will require you to look up other equations. Furthermore, the student must know that having a ruler becomes particularly handy in CBE 250, as straight lines are critical for correct McCabe Thiele diagrams. Piazza also becomes very helpful to the student in preparation for assessments. Often Link and the TAs will clarify a common mistake or misunderstanding from the homeworks, and the ensuing discussion can provide some insight. For example, past answers have been about the difference between pore length and pore diameter in membranes, the assumption regarding to area of a benzene molecule (to calculate a monolayer), etc. As a reminder, questions are usually answered within 24 hours on weekdays, and often much quicker. The problems on the midterm and final exam should look very familiar to those on the problem sets. The biggest factor on the midterm seems to be time management, rather than the sheer difficulty of the problems themselves. Like other classes, past midterm and final exams prove helpful to the student, and all should be completed before each of the assessments (usually 3-4 past copies are provided on Piazza). Finally, since the final exam is open textbook, it is wise for the student to purchase (even if used) a copy of the Seader textbook. This is not the typical engineering course in which one can get by without the textbook. It should also be mentioned that regrades on the midterm are sometimes given, but points are given back only if there is truly an argument to be made in favor of the student: be sure to look at the midterm solutions if that applies to you, because points will not be given back arbitrarily

External Resources

With this class, there are enough resources provided such that external ones should not be necessary. The homeworks, solutions, lecture notes, textbook, and finally piazza discussions should provide ample study material. See III for use of Piazza.

What Students Should Know About This Course For Purposes Of Course Selection

CBE 250 is required for CBE concentrators, and is rarely taken by anyone outside the department. While this course is challenging, CBE 250 is one of the more manageable CBE courses given the proper preparation and work. Though students may not initially expect so, the concepts in CBE 250 – particularly distillation columns – become very key in later CBE courses (such as Core Lab and even Design). The problem sets do take some time, particularly towards the latter third of the course, but this course will help appreciate some of the complexities of chemical engineering in industry, instead of learning about ChemE on a abstract spectrum as some other classes tend to veer. Finally, it cannot be stressed enough that the student should go to lecture. Professor Link genuinely cares about teaching his students, and takes care to prepare these lectures and the material as well.
Separations in Chemical Engineering and Biotechnology

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