The batch reactor is the generic term for a type of vessel widely used in the process industries. Its name is something of a misnomer since vessels of this type are used for a variety of process operations such as solids dissolution, product mixing, chemical reactions, batch distillation, crystallization, liquid/liquid extraction and polymerization. In some cases, they are not referred to as reactors but have a name which reflects the role they perform (such as crystallizer, or bioreactor)
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 toxic or highly potent compounds.
A Reactor is essentially an industrial "pressure cooker", where the contents (such as pharmaceutical powders and API's) are sealed and transformed, under pressure and/or temperature, to a new desired substance.
Reactors are a critical and very important element in production lines in modern process plants and are widely used in the fields of petrochemicals, light industry, pharmaceuticals, pesticide, food, dyes and scientific research.