Unit 18. Reaction Engineering of Batch Reactors

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.

Section B of Part III examines reaction engineering for perfectly mixed batch reactors. Typical reaction engineering tasks involving batch reactors are identified and described. In order to become a proficient reaction engineer, one must develop an intuitive appreciation of how a reactor responds to changes in operational procedures. For this reason a detailed discussion of the qualitative analysis of batch reactors is presented in this section along with the full mathematical analysis of their behavior.

Unit 18 describes some of the more common reaction engineering tasks that involve batch reactors. It also describes how to qualitatively analyze a batch reactor. This is an important skill for a good reaction engineer to master. An intuitive, physical understanding of why the temperature, pressure, composition, etc. change in the way they do for a given combination of reaction, reactor and reactor operating procedure can prove invaluable when troubleshooting a problematic reactor or when setting out to design a new one. Unit 18 shows that it is possible to predict, at least qualitatively, many things about reactor performance without ever solving the design equations.

Learning Resources

• Archive (.zip) - Contains all learning resources listed below for this unit
• Documents to Read:
  • Unit 18 Informational Reading (.pdf)
  • Example 18.1 (.pdf)
  • Example 18.2 (.pdf)
  • Example 18.3 (.pdf)
• Videos to Watch (please right-click and save, then play back locally on your computer):
  • Unit 18 Informational Video (.mov)
  • Example 18.1 Video (.mov)
  • Example 18.2 Video (.mov)
  • Example 18.2 Video (.mov)
• Reference Files:
  • Unit 18 Definitions, Nomenclature and Equations (.pdf)
• Simulators
  • Batch Reactor 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
• Alternative Questions (.pdf) that could be used in a pre-class quiz
• Simulator Source files
  • Batch Reactor 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. Consider a typical reaction that is reversible and exothermic. Suppose that reaction is run two separate times using a batch reactor. The reactor volume, initial composition and initial temperature are the same in both of the runs. One run is conducted isothermally and the other is conducted adiabatically. Sketch the conversion versus time for the two runs on the same set of axes. Your sketch should be sufficiently detailed to show initial and final slopes, curvature, inflection points, etc. If your artistic skills are weak, you should provide a brief written description of the two curves that describes these aspects.

2. Consider the exothermic, reversible reaction A → B. The reaction is first order in both directions. Suppose the reaction was run isothermally at each of two different temperatures. The initial concentration of A was the same in both runs and there was no B present initially in either run. (a) Sketch the concentration of A as a function of time for both runs on the same set of axes. (b) Sketch the fractional conversion of A as a function of time for both runs on the same set of axes.

(Problem Statement as .pdf file)