HHT offers continuous stirred reactor designs depending on the reaction chemistry. When low conversions of reactants are needed , a single stirred reactor may be operated continuously by feeding the raw materials and catalyzed solution while removing a constant product stream. Additional mass transfer may be achieved within the single stirred reactor by dividing the reactor into compartments while minimizing back-mixing and short-circuiting.
When high conversions of reactants are needed, several stirred reactors in series can be used (cascade stirred reactors). The larger the number of stirred reactor, the closer the performance approaches that of a tubular plug-flow reactor.
The continuous stirred reactor designs offer:
- simpler and easier to design for isothermal operation than tubular reactors.
- Reactions with narrow operating temperature ranges or those requiring close control of reactant concentrations benefit from cascade arrangements.
- For very reactive systems heating or cooling zones inside or outside (external loop heat exchanger) can be incorporated to the stirred reactor. Inside design with centrally mounted draft tubes that circulate liquid upward, then downward through vertical heat-exchanger tubes.
- In a similar fashion, reactor contents can be recycled through external heat exchangers.
- Easier process control compared to batch process
- Construction simplicity
- Low labor operating cost