Page 18 - Modeling of Chemical Kinetics and Reactor Design

Table 1
Some branches of science to which kinetics is relevant [1]
Branch Applications of kinetics

Biology Physiological processes (e.g., digestion and metabolism),
bacterial growth
Chemical engineering Reactor design
Electrochemistry Electrode processes
Geology Flow processes
Inorganic chemistry Reaction mechanisms

Mechanical engineering Physical metallurgy, crystal dislocation mobility
Organic chemistry Reaction mechanisms
Pharmacology Drug action
Physics Viscosity, diffusion, nuclear processes
Psychology Subjective time, memory

CASE STUDY

As an introduction to the modeling of chemical kinetics and reactor
design, consider the manufacture of ammonia. The synthesis of ammonia
is performed on a large scale with over 100 million tons produced each
year. Computer simulation of the plant is increasingly employed as
the first stage in identifying which parameters control the conversion
rate, the product purity, the energy expended, and the production rate.
The economic considerations that affect the reduction of costs with
increased efficiency and profitability are high. The principal licensors
of ammonia synthesis are ICI, Braun, and M.W. Kellogg. Figure 1
shows a typical ammonia plant.
Ammonia is one of the largest volume inorganic chemicals in the
chemical process industries. Its major applications are in the pro-
duction of fertilizers, nitrates, sulfates, phosphates, explosives, plastics,
resins, amines, amides, and textiles. The fertilizer industry is the
largest user of ammonia, and large quantities must be stored to meet
the demand and maintain constant production levels. Ammonia may
be stored in very large insulated tanks at pressure near ambient; in
large spheres at a moderate pressure, refrigerated to reduce the
pressure; and at ambient temperature but higher pressure, corresponding
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