CONTENTSFront MatterCourse UnitsI. Chemical Reactions
II. Chemical Reaction Kinetics
A. Rate Expressions
B. Kinetics Experiments
C. Analysis of Kinetics Data
III. Chemical Reaction Engineering
A. Ideal Reactors
B. Perfectly Mixed Batch Reactors
C. Continuous Flow Stirred Tank Reactors
D. Plug Flow Reactors
E. Matching Reactors to Reactions
IV. Non-Ideal Reactions and Reactors
A. Alternatives to the Ideal Reactor Models
B. Coupled Chemical and Physical Kinetics
Supplemental Units |
Unit 34. 2-D and 3-D Tubular Reactor ModelsThis website provides learning and teaching tools for a first course on kinetics and reaction engineering. In the preceding parts of the course, the reacting fluid was always treated as if it was homogeneous, and only ideal reactor types were considered. The knowledge gained to this point is sufficient for reaction engineering for many commercial processes. Nonetheless, there are situations where the reactor does not conform to one of the ideal types and/or the rates are affected by the kinetics of physical processes in addition to the chemical reaction rate. Part IV of the course surveys a few such situations. It does not provide an in-depth analysis of any of them, but the information provided should serve as a good foundation for further study. The first section of Part IV considers reactors that do not satisfy the assumptions of any of the ideal reactor types. It touches upon three approaches to modeling such reactors. One approach is to increase the rigor of the ideal reactor models by changing one of more of the assumptions that define the ideal reactor, but retaining most of the original model. A second approach is to effectively abandon rigor in favor of a quantitatively accurate description of the reactor behavior. The last approach uses statistical methods to describe the performance of a reactor. Section A then concludes by considering changes that are necessary when modeling reactors wherein two phases are involved in the reaction(s) taking place, and presenting with an overview of reactors that are used when the reaction involves two or more phases. Unit 34 describes two- and three-dimensional models for tubular reactors. One limitation of the PFR model is that the temperature and composition cannot vary in the radial direction. This can be a serious shortcoming in some situations, such as those involving heat transfer through the reactor walls. There are also situations where variations in the angular direction are important, such as radiant heating configurations where the radiation only “sees” one side of the tube. In cases like these, a more rigorous model that allows for three dimensional variation may be necessary. Learning Resources
Teaching Resources
Practice Problemsto be added. |