Page 284 - Elements of Chemical Reaction Engineering 3rd Edition

256 Collection and Analysis of Rate Data Chap. 5

TABLE E5-6.1, DIFFERENTIAL REACTOR DATA
Run Reaction Rate PE PEA PH
Number (mol/kg cat. .s) (atm) (atm) (atm)
1 1.04 1 1 1
2 3.13 1 1 3
3 5.21 1 1 5
4 3.82 3 1 3
5 4.19 5 1 3
6 2.391 0.5 I 3
I 3.867 0.5 0.5 5
8 2.199 0.5 3 3
9 0.75 0.5 5 1
-

Determine which of the following rate laws best describes the data.

(d) - rA = kPiPL

Solution
POLYMATH was chosen as the software package to solve this problem. The data in
Table E5-6.1 were typed into the system. The following copies of the computer
screens illustrate the procedure.
Procedure 1. First we enter the data in Table E5-6.1 into the POLYMATH table shown
Enter data in Table E5-6.2. After entering the data and pressing shift F7, the following solu-
Enter model tion options appear on the screen:
Make initial
estimates of
parameters
Run regression
Examine
parameters and p. Fir a polynomial. P. Polynornlal passing through oriqin.
variance s. Fir a cubic spline. R. 00 nonlinear regression.
Observe error 'j? or F8 for problen options
dimbution
Choose model
Next we type R and choose a model to fit the data.
2. Specify the model and determine the model parameters and a2. The first
model we choose is model (a).

(E5-6.1)

Next we enter the model Equation (E5-6.1) and initial estimates of the parameter
values.