Page 263 - Elements of Chemical Reaction Engineering 3rd Edition

Sec. !5.1 Batch Reactor Data 235
5. Deternline the specific reaction rate. The specific reaction rate can be: deter-
mined using Equation (E5-1.7) with a = 1 and then evaluating the numerator and
denominator at any point, p.

At (3P,- P) = 5.0 mmHg,
dp -_ - 0.4 minHg/min
dt
From Equation (E5-1.3,

-
- 0.4 mmHg/min = 0.08 min-l
5.0 mmHg
The rate law is

(E5- 1.13)

5.1.2 Integral Method

To determine the reaction order by the integral method, we guess the
reaction order and integrate the differential equation used to model the batch
system. If the order we assume is correct, the appropriate plot (determined
The integral from this integration) of the concentration-time data should be linear. The inte-
method uses a trial- gral method is used most often when the reaction order is known and it is
and-emr procedure
to find reactiori desired to evaluate the specific reaction rate constants at different temperatures
order to determine the activation energy.
I[n the integral method of analysis of rate data we are looking for the
appropriate function of concentration corresponding to a particular rate law
that is linear with time. You should be thoroughly familiar with the methods of
obtaining these linear plots for reactions of zero, first, and second order.
For the reaction

A +products
It is important to carried out in a constant-volume batch reactor, the mole balance is
know how to
generate linear
plots of functions of
versus t
for zero-, first-, and
second-order For a zero-order reaction, rA = - k, and the combined rate law and mole bal-
reactions ance is;

(5-13)