Biotechnology: Stirred Tank Reactors

What is the primary function of a sparger in a stirred tank bioreactor?

If the height of liquid in a stirred tank bioreactor is twice the tank diameter, what is the recommended configuration of agitators?

What happens when the mass flow rate in a continuous stirred tank reactor does not equal the flow rate out?

How is the residence time in a CSTR calculated?

What is a key characteristic of the exit stream of a CSTR?

What role do impellers play in a stirred tank bioreactor?

When installing multiple sets of impellers in a stirred tank, what is the recommended separation distance?

In a stirred tank bioreactor, what is the consequence of having a non-uniform gas distribution?

What must be true about the composition of the feed in a continuous stirred tank reactor?

Which of the following describes a steady state in a CSTR?

Stirred Tank Bioreactors (STRs)

Air is introduced into the culture medium under pressure via a sparger, which can be a ring with holes or a tube with a single orifice.
Spargers, in conjunction with impellers (agitators), facilitate effective gas distribution throughout the bioreactor.
Impellers break down air bubbles into smaller sizes, ensuring uniform dispersion of gas in the medium, thus creating a homogeneous environment.

Agitator Specifications

The number of agitators on the shaft correlates with the height of the liquid in the vessel.
For optimal mixing, the liquid height should align with the designated height; mixing occurs efficiently with a single set of agitators.
If liquid height exceeds two or three times the tank diameter (H = 2T or 3T), additional agitators are required on the same shaft.
Impellers should be spaced at a distance of 4T apart to enhance mixing and mass transfer performance.

Continuous Stirred-Tank Reactor (CSTR) Characteristics

CSTR operates at steady state, where the inlet flow rate must equal the outlet mass flow rate to prevent overflow or emptying.
The feed has a uniform composition; the exit stream mirrors the concentration found within the tank.
Reaction rates are dependent on the final output concentration.
An impeller is installed to ensure efficient mixing within the reactor.
The residence time is calculated by dividing the tank's volume by the average volumetric flow rate, representing how long a reagent spends in the tank.

This quiz explores the principles and mechanisms of stirred tank bioreactors (STRs). Learn about the role of spargers and impellers in enhancing gas distribution in culture mediums. Test your knowledge on the various types of spargers used and their impact on cell culture processes.