Unit 25. Reaction Engineering of PFRs

This website provides learning and teaching tools for a first course on kinetics and reaction engineering. Here, in Part III of the course, the focus is on the modeling of chemical reactors. In particular, it describes reaction engineering using the three ideal reactor types: perfectly mixed batch reactors, continuous flow stirred tank reactors and plug flow reactors. After considering each of the ideal reactor types in isolation, the focus shifts to ideal reactors that are combined with other reactors or equipment to better match the characteristics of the reactor to the reactions running within it.

Reaction engineering of the third of the three ideal reactor types, the plug flow reactor (PFR), is the subject of Section D of Part III. The discussion parallels that of the previous two sections: typical reaction engineering tasks are defined, qualitative performance is examined and full mathematical analysis is described and illustrated. Similar to CSTRs, plug flow reactors are typically designed to operate at steady state, but their start-up and shut-down involves transient operation, so both modes of operation are considered in this section.

Unit 25 begins the analysis of the third and final ideal reactor type, namely the plug flow reactor. This unit describes the kinds of tasks one may need to accomplish during the reaction engineering of PFRs. The information is very similar to that for CSTRs, since both are flow reactors. It also includes a discussion of the qualitative analysis of PFRs, showing that their performance is often the same as a batch reactor if one substitutes the PFR residence time in place of the duration of a batch reaction process.

Learning Resources

• Archive (.zip) - Contains all learning resources listed below for this unit
• Documents to Read:
  • Unit 25 Informational Reading (.pdf)
  • Example 25.1 (.pdf)
• Videos to Watch (please right-click and save, then play back locally on your computer):
  • Unit 25 Informational Video (.mov)
  • Example 25.1 Video (.mov)
• Simulators
  • Isothermal PFR Simulator (zipped .jar file)
  • Adiabatic PFR Simulator (zipped .jar file)
   
  Please note that these simulators are intended for educational purposes only. They should not be used for any other purpose, and if they are, the author does not bear any responsibility or liability for the consequences.
   
  The “zipped .jar file,” when unzipped, will produce a folder that contains a .jar file and a folder named "lib". Not surprisingly the latter folder contains additional libraries and files that the simulator uses. To run the simulator, launch the .jar file either from the command line using java -jar [name of .jar file], or by double clicking it if your operating system supports it. The simulators require JAVA 1.6 or later in order to run. There is a User's Guide under the Help menu that describes how to use the simulators.
   
  

Teaching Resources

• Archive (.zip) - Contains all teaching resources listed below for this unit
• Sample Class
  • Online Pre-class Quiz (.pdf file)
  • Redacted slides to make available to students before class
    • Keynote 09
    • PowerPoint
  • Class Lesson Plan (.pdf)
  • Complete slides to make available to students after class
    • Keynote 09
    • PowerPoint
• Simulator Source files
  • Isothermal PFR Simulator (zipped Netbeans project folder)
  • Adiabatic PFR Simulator (zipped Netbeans project folder)
   
  Please note that these simulators are intended for educational purposes only. They should not be used for any other purpose, and if they are, the author does not bear any responsibility or liability for the consequences.
   
  The “Netbeans Project folders” contain the Netbeans java project used to create them. Providing them in this way will allow instructors or students familiar with java and the Netbeans development environment to modify them. They were developed using version 6.7 of Netbeans. They use the Swing Application Framework, which is not supported in version 7.1 or higher of the Netbeans IDE. They are no longer in development, and I am not available to consult on any issues encountered when using them.

Practice Problems

1. Suppose reaction (1a) occurs adiabatically in a steady state PFR, with the temperature and concentration profiles shown in Figures 1 and 2 in this .pdf file. How would the temperature and concentration profiles change if the reaction was run adiabatically using the same feed temperature and composition in the same steady state reactor, but with the volumetric flow rate doubled?

(Problem Statement as .pdf file)