Chapter 18: Models for Nonideal Reactors
Self Test 14.1: Sketch of F curves
The F curves for two different tubular reactors is shown below, for a closed–closed system
(a) Which curve has the higher Peclet number? Explain.
(a) Curve 1
(b) Curve 2
(c) Curve 3
(b) Which curve has the higher dispersion coefficient? Explain.
(a) Curve 1
(b) Curve 2
(c) Curve 3
(c) If this F-curve is for the tanks-in-series model applied to two different reactors which curve uses the largest number of tanks to model the real reactor, (1) or (2)?
(a) Curve 1
(b) Curve 2
(c) Curve 3
Solution
For plug flow (Da = 0 and Pe = ¥) we have
For small deviation from plug flow
For a CSTR Da = ¥ ‚
(a) For small Da large Pe.
(b) For large Da small Pe
(c) For Plug flow represented by tanks-in-series n ® ¥. Therefore curve (1) is close to plug flow, therefore n is greater for modeling curve than for curve ‚.