Chemical Reaction Engineering Asynchronous Video Series Chapter 2: Conversion and Reactors in Series H. Scott Fogler, Ph.D.

Reactor Mole Balance Summary

Conversion

Batch Reactor Conversion For example, let’s examine a batch reactor with the following design equation:

Batch Reactor Conversion For example, let’s examine a batch reactor with the following design equation: Consider the reaction:

Batch Reactor Conversion For example, let’s examine a batch reactor with the following design equation: Consider the reaction:

Batch Reactor Conversion For example, let’s examine a batch reactor with the following design equation: Consider the reaction: Differential Form: Integral Form:

CSTR Conversion Algebraic Form: There is no differential or integral form for a CSTR.

PFR Conversion PFR

PFR Conversion PFR

PFR Conversion PFR Differential Form: Integral Form:

Design Equations

V

V

Example

0 0.01

Example

Example 0 X

Reactor Sizing Given -r A as a function of conversion, -r A =f(X), one can size any type of reactor.

Reactor Sizing Given -r A as a function of conversion, -r A =f(X), one can size any type of reactor. We do this by constructing a Levenspiel plot.

Reactor Sizing Given -r A as a function of conversion, -r A =f(X), one can size any type of reactor. We do this by constructing a Levenspiel plot. Here we plot either as a function of X

Reactor Sizing Given -r A as a function of conversion, -r A =f(X), one can size any type of reactor. We do this by constructing a Levenspiel plot. Here we plot either as a function of X. For vs. X, the volume of a CSTR is: Equivalent to area of rectangle on a Levenspiel Plot X EXIT

Reactor Sizing Given -r A as a function of conversion, -r A =f(X), one can size any type of reactor. We do this by constructing a Levenspiel plot. Here we plot either as a function of X. For vs. X, the volume of a CSTR is: For vs. X, the volume of a PFR is: Equivalent to area of rectangle on a Levenspiel Plot X EXIT = area under the curve =area

Numerical Evaluation of Integrals The integral to calculate the PFR volume can be evaluated using Simpson’s One-Third Rule:

Numerical Evaluation of Integrals The integral to calculate the PFR volume can be evaluated using Simpson’s One-Third Rule (see Appendix A.4 on p. 924):

Reactors In Series

Reactors in Series Also consider a number of CSTRs in series:

Reactors in Series Finally consider a number of CSTRs in series: We see that we approach the PFR reactor volume for a large number of CSTRs in series: X

Summary