Page 82 - Modeling of Chemical Kinetics and Reactor Design

52 Modeling of Chemical Kinetics and Reactor Design

Figure 1-7. Lineweaver-Burk plot of (1/C urea ) versus (1/V ).
o

The overall reaction is:

CH = CH + H
2 6 2 4 2
The reaction is first order in the temperature range of 550–640°C
and at pressure in excess of 50 mm Hg. The rate law is given by

dC
2
− ( r ) =− CH 6 = kC
CH 6 dt CH 6
2
2
(1) Develop a mechanism to account for the first-order rate law for
the case where only methane is formed as a byproduct. Assume that
the chain length is large.

Mechanism

Initiation

1. C H → CH + CH * 3 (1-222)
*
k 1
3
2
6

2. CH + C H  → CH + C H * 5 (1-223)
*
k 2
2
4
6
2
3