Page 30 - Elements of Chemical Reaction Engineering Ebook

Mole Balances 1

The first step to knowledge
is to know that we are ignorant.
Socrates (470-399 B.c.)

Chemical kinetics and reactor design are at the heart of producing almost id1
industrial chemicals. It is primarily a knowledge of chemical kinetics and reac-
tor design that distinguishes the chemical engineer from other engineers. %he
selection of a reaction system that operates in the safest and most efficient
manner can be the key to the economic success or failure of a chemical plant.
For example, if a reaction system produced a large amount of undesirable
product, subsequent purification and separation of the desired product could
make the entire process economically unfeasible. The chemical kinetic princi-
ples leanied here, in addition to the production of chemicals, can be applied in
areas such as living systems, waste treatment, and air and water pollutioln.
Some of the examples and problems used to illustrate the principles of chemi-
cal reaction engineering are: the use of wetlands to remove toxic chemicals
from rivers, increasing the octane number of gasoline, the production of anti-
freeze starting from ethane, the manufacture of computer chips, and the appli-
cation of enzyme kinetics to improve an artificiaI kidney.
This book fcicuses on a variety of chemical reaction engineering topics.
It is concerned with the rate at which chemical reactions take place, together
with the mechanism and rate-limiting steps that control the reaction process.
The sizing of chemical reactors to achieve production goals is an important
segment. How materials behave within reactors, both chemically and physi-
cally, is significant to the designer of a chemical process, as is how the data
from chemical reactors should be recorded, processed, and interpreted.
Before entering into discussions of the conditions that affect chemical
reaction rates and reactor design, it is necessary to account for the varioius
chemical species entering and leaving a reaction system. This accounting pno-
cess is achieved through overall mole balances on individual species in the
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