CONTENTS

Front Matter

Title Page, Preface and Acknowledgements
About the Author
Status, History, Issues and Updates
Complementary Textbooks
Teaching Notes and Resources
A Note about Numerical Solutions

Course Units

I. Chemical Reactions
1. Stoichiometry and Reaction Progress
2. Reaction Thermochemistry
3. Reaction Equilibrium
II. Chemical Reaction Kinetics
A. Rate Expressions
4. Reaction Rates and Temperature Effects
5. Empirical and Theoretical Rate Expressions
6. Reaction Mechanisms
7. The Steady State Approximation
8. Rate-Determining Step
9. Homogeneous and Enzymatic Catalysis
10. Heterogeneous Catalysis
B. Kinetics Experiments
11. Laboratory Reactors
12. Performing Kinetics Experiments
C. Analysis of Kinetics Data
13. CSTR Data Analysis
14. Differential Data Analysis
15. Integral Data Analysis
16. Numerical Data Analysis
III. Chemical Reaction Engineering
A. Ideal Reactors
17. Reactor Models and Reaction Types
B. Perfectly Mixed Batch Reactors
18. Reaction Engineering of Batch Reactors
19. Analysis of Batch Reactors
20. Optimization of Batch Reactor Processes
C. Continuous Flow Stirred Tank Reactors
21. Reaction Engineering of CSTRs
22. Analysis of Steady State CSTRs
23. Analysis of Transient CSTRs
24. Multiple Steady States in CSTRs
D. Plug Flow Reactors
25. Reaction Engineering of PFRs
26. Analysis of Steady State PFRs
27. Analysis of Transient PFRs
E. Matching Reactors to Reactions
28. Choosing a Reactor Type
29. Multiple Reactor Networks
30. Thermal Back-Mixing in a PFR
31. Back-Mixing in a PFR via Recycle
32. Ideal Semi-Batch Reactors
IV. Non-Ideal Reactions and Reactors
A. Alternatives to the Ideal Reactor Models
33. Axial Dispersion Model
34. 2-D and 3-D Tubular Reactor Models
35. Zoned Reactor Models
36. Segregated Flow Models
37. Overview of Multi-Phase Reactors
B. Coupled Chemical and Physical Kinetics
38. Heterogeneous Catalytic Reactions
39. Gas-Liquid Reactions
40. Gas-Solid Reactions

Supplemental Units

S1. Identifying Independent Reactions
S2. Solving Non-differential Equations
S3. Fitting Linear Models to Data
S4. Numerically Fitting Models to Data
S5. Solving Initial Value Differential Equations
S6. Solving Boundary Value Differential Equations

Unit 1. Stoichiometry and Reaction Progress

This website provides learning and teaching tools for a first course on kinetics and reaction engineering. The course is divided into four parts (I through IV). Here, in Part I of the course, a brief review of some basic concepts related to chemical reactions is presented. Students taking their first kinetics and reaction engineering course should already be familiar with most of the material that is presented in this part of the course. The concepts that are reviewed here will be utilized repeatedly throughout the remainder of the course, and therefore it is critically important to master them before proceeding to the main body of the course, Parts II, III and IV.

Unit 1 reviews some basic concepts related to chemical reactions. The first topic is reaction stoichiometry, and it includes the sign convention for stoichiometric coefficients that will be used throughout this course. The remainder of the unit reviews how stoichiometry can be used when calculating the composition of a reacting system as the reaction or reactions proceed. In doing so, some common reaction progress variables are introduced and defined.

Learning Resources

Teaching Resources

  • Archive (.zip) - Contains all teaching resources listed below for this unit
  • Sample Class
  • Alternative Questions (.pdf) that could be used in a pre-class quiz
  • Alternative In-Class Learning Activities
    • Alternative Activity 1.1 (.zip) - an activity where the students will draw upon their own life experiences to illustrate, by analogy, the primary focus of kinetics, thermodynamics and reaction engineering and the inter-relationships between them.
    • Alternative Activity 1.2 (.zip) - an activity where the students will use physical models of molecules to explore the origins of reaction stoichiometry.
    • Alternative Activity 1.3 (.zip) - an activity where the students will work in groups to prepare a three slide presentation describing how to find a complete mathematically independent sub-set of a group of reactions.
    • Alternative Activity 1.4 (.zip) - an activity where the students will “explore and learn” about reaction progress variables individually or in a group.

Practice Problems

1. Cellulosic biomass is a renewable resource that could be used for the production of fuels and chemicals. Suppose that the nominal chemical formula for cellulose is C6H10O5 and write a balanced chemical reaction for the steam gasification of cellulose to produce carbon monoxide and hydrogen (H2). List the values of the four stoichiometric coefficients that appear in the reaction. (Problem Statement as .pdf file)

2. Several words and phrases from Unit 1 are hidden in this puzzle (.pdf). The words may appear right to left, left to right, top to bottom, bottom to top or in either direction along a diagonal. Find as many terms as you can and write a brief definition for each one you find. There are at least 19 items, along with a few bonuses, hidden in the puzzle. (Problem Statement as .pdf file)

3. In the gasification of cellulosic biomass (here represented using its nominal formula, C6H10O5), the carbon from the cellulose could be released either as CO (see Practice Problem 1), or as CO2, reaction (3a). In addition, the water-gas shift, reaction (3b), can lead to a mixture of CO and CO2. Suppose a reaction began with 10 moles of H2O for every one mole of C6H10O5, and no other species present. If half of the cellulose is consumed and the products contain 3 moles of CO2 for every mole of CO, what will the ratio of CO to H2 equal?

  C6H10O5 + 7 H2O → 6 CO2 + 12 H2 (3a)  
  CO + H2O → CO2 + H2 (3b)  

(Problem Statement as .pdf file)

4. The gas phase reaction 2 NO + 5 H2 → 2 NH3 + 2 H2O takes place in a system that initially contained 2 moles of H2 and 1 mole of NO. If 50% of the limiting reagent is converted, what will the mole fraction of ammonia equal? (Problem Statement as .pdf file)

5*. A graduate student was studying the gas phase decomposition of N2O according to reaction (5a). The student ran several experiments involving this reaction using a steady-state flow reactor. The feed to the reactor always contained a mixture of helium and nitrous oxide (neither oxygen nor nitrogen was ever used in the feed), and the total pressure was 1 atm in each experiment. The inlet flow rates and the reactor temperature were held constant in each individual experiment. A gas chromatograph was used to measure the composition of the gas leaving the reactor. Using the data from the gas chromatograph, the student was easily able to calculate the mole fraction of oxygen leaving the reactor. Use the experimental data provided in the table below (or as an Excel file here) to calculate the outlet concentrations of N2O, N2 and O2 for each of the student's experiments.

  2 N2O → 2 N2 + O2 (5a)  
 
Temperature Inlet molar flow rate (μmol/s) Outlet O2 mole
(K) N2O He fraction
---------- ---------- ---------- ----------
785 0.473 21.7 0.00755
785 1.15 20.8 0.01824
785 1.13 20.8 0.01772
786 1.54 20.2 0.02426
787 1.98 19.6 0.03241
790 3.2 17.8 0.05686
760 0.861 21.3 0.00723
761 1.26 20.8 0.01088
761 2.19 19.7 0.02043
762 3.19 18.3 0.03574
736 1.97 20.2 0.00541
736 2.46 19.7 0.00670
736 4.08 18.0 0.01208
736 4.31 17.7 0.01406
737 5.35 16.5 0.01957

(Problem Statement as .pdf file)

6. Steam reforming of methane, reaction (6a) is used commercially to manufacture hydrogen. Suppose a 10 L reactor initially contains a gas mixture with 70% steam and 30% methane at 2 atm and 375 °C. Assuming reaction (6a) is the only reaction that takes place and that the temperature is constant, (a) calculate the final concentration of hydrogen if 95% of the methane is converted. (b) Derive an expression (valid at any conversion) for the concentration of steam in terms of the reactor volume, the initial moles of steam, the initial moles of methane and the final moles of methane.

  CH4 + H2O → CO + 3 H2 (6a)  

(Problem Statement as .pdf file)

7. Suppose that a flow reactor operates isothermally at 800 K and 3 atm where ideal gas behavior can be assumed. A gas mixture at 800 K and 3 atm containing 90% N2, 8% O2 and 2% NH3 by volume flows into the reactor at a rate of 4 L min-1 and reacts according to reaction (7a).

(a) If this reactor was being used to generate kinetics data, it might be necessary to write an expression for the outlet partial pressure of ammonia in terms of known constants and the outlet molar flow rate of ammonia in order to analyze the data. In doing so, it is important to recognize that the total outlet molar flow rate will change when the outlet molar flow rate of ammonia changes. Write the expression for the outlet partial pressure of ammonia in terms of known constants and the outlet molar flow rate of ammonia.

(b) Further suppose that in one kinetics experiment using this reactor, the outlet flow was found to contain 1.6% NO. During the analysis of the data, it might also be necessary to calculate the outlet molar flow rate of NH3 in this experiment. What is the outlet molar flow rate of ammonia in this experiment and what ammonia conversion does this correspond to?

  4 NH3 + 5 O2 → 4 NO + 6 H2O (7a)  

(Problem Statement as .pdf file)

* This problem introduces something new that wasn't encountered in the informational or illustrational readings and videos.