Biomedical Engineering Reference
In-Depth Information
CHAPTER
4
Batch Reactor
OUTLINE
4.1. Isothermal Batch Reactors
142
4.4. Numerical Solutions of Batch
Reactor Problems
165
4.2. Batch Reactor Sizing
155
4.5. Summary
172
4.3. Non-Isothermal Batch Reactors
159
Problems
173
The batch reactor is the generic term for a type of vessel widely used in the process indus-
tries. Batch reactors are used for a variety of process operations such as solid dissolution,
product mixing, chemical reactions, crystallization, liquid/liquid extraction, and polymeri-
zation. In some cases, they are not referred to as reactors but have a name that reflects the
role they perform (such as crystallizer or bioreactor).
A typical batch reactor consists of a tank with an agitator and integral heating/cooling
system. These vessels may vary in size from less than 1 L to more than 15,000 L. They are
usually fabricated in steel, stainless steel, alloys, glass lined steel, glass, Plexiglas, china,
brick, cement, plastics, and even wood. Liquids and solids are usually charged via connec-
tions on the top cover of the reactor. Vapors and gases also discharge through connections
on the top. Liquids and solids are usually discharged out of the bottom.
The advantages of the batch reactor lie with its versatility. A single vessel can carry out
a sequence of different operations without the need to break containment. This is particularly
useful when processing multiple feedstocks, toxic, or highly potent compounds or producing
different unrelated products.
Commonly seen batch reactors are pots (in the kitchen
e
cooking), frying pans, pickling
jars, beakers and test tubes (in chemistry laboratories), anaerobic digestion pits, to name
a few. Batch reactor is an idealized reactor such that there are no inlets to or outlets from
the reactor. Furthermore, in this text, we assume that the reaction mixture is well mixed all
the time inside a batch reactor. Therefore, the temperature and concentrations are uniform
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