CBE 30356 - Lecture Notes - March 28, 2023
Announcements
Class notes
Read through pages 253-263 of the notes and view the online narration below. Don't forget to complete the quiz in Canvas!
The main points of the lecture were
- Gas phase mass transfer with reaction
- The Thiele Modulus and Effectiveness Factor
Goals:
After this class you should be able to:
- Know the difference between heterogeneous and homogeneous reactions are (and how to treat them in mass transfer problems!).
- Know who Ernest Thiele was (a famous ChE who taught at ND for a decade).
- Determine how mass transfer affects reaction rates in a catalyst pellet.
Reading
- The class notes.
- BS&L, 18.3, 18.7
Problem of the Day:
In this problem we derive Thiele's Effectiveness Factor for a flat catalyst particle and demonstrate its similarity to the result for a sphere. Since these are probably the most dissimilar shapes, it shows that the simple expression using a Thiele modulus based on the volume/surface ratio is a pretty good approximation for general shapes (e.g., cylindrical pellets, etc.). The notes for this are provided here.
Demonstration:
David.T.Leighton.1@nd.edu