The seminar by Urmila N. Pai discusses different bioreactor configurations, including stirred tank, bubble column, airlift, packed-bed, trickle-bed, and fluidized bed reactors. Each type has unique mixing methods, designs, and applications, with advantages and disadvantages related to operation, efficiency, and suitability for specific processes. The presentation emphasizes the importance of reactor design in optimizing chemical reactions in various industrial contexts.

1. Different configurations of
bioreactor
Seminar by,
Urmila .N.Pai
6th sem
SCET

2. - 1. Stirred tank

3. The continuous stirred-tank reactor, also
known as vat- or backmix reactor, is a common ideal
reactor type in chemical engineering.
A CSTR oftenrefers to a model used to estimate
the key unit operation variables when using a
continuous agitated-tank reactor to reach a specified
output.

4. Mixing method: Mechanical agitation
•Baffles are usually used to reduce vortexing
• Applications: free and immobilized enzyme
reactions
•High shear forces may damage cells
•Require high energy input

5. - 2. Bubble column

6. • Mixing method: Gas sparging
• Simple design
• Good heat and mass transfer
• Low energy input
• Gas-liquid mass transfer coefficients depend largely
on bubble diameter and gas hold-up.

8. - 3. Airlift reactor

9. Air-lift bioreactors are similar to bubble column
reactors, but differ by the fact that they contain a draft
tube.
The draft tube is always an inner tube (this kind of
air-lift bioreactor is called "air-lift bioreactor with an
internal loop) or an external tube (this kind of air-lift
bioreactor is called "air-lift bioreactor with an external
loop) which improves circulation and oxygen transfer and
equalizes shear forces in the reactor

10. • Mixing method: airlift
• Compared to bubble column reactors, in an airlift
reactors, there are two liquid steams: up-flowing and
down-flowing steams. Liquid circulates in an airlift
reactor as a result of density difference between riser
and downcomer.

11. 4. Packed-bed reactor

12. • Packed-bed reactors are used with immobilized or
particulate biocatalysts.
• Medium can be fed either at the top or bottom and
forms a continuous liquid phase.

13. • In packed bed reactors, cells are immobilized on large
particles. These particles do not move with the liquid.
Packed bed reactors are simple to construct and
operate but can suffer from blockages and from poor
oxygen transfer.
• Continuous packed bed reactors are the most widely
used reactors for immobilized enzymes and
immobilized microbial cells. In these systems, it is
necessary to consider the pressure drop across the
packed bed or column, and the effect of the column
dimensions on the reaction rate.

14. • There are three substrate flow possibilities in a
packed bed and they are illustrated below:
• 1. Downward flow method
• 2. Upward flow method
• 3. Recycling method
• The recycling method is advantageous when the
linear velocity of the substrate solution affects the
reaction flow rate. This is because the recycling
method allows the substrate solution to be passed
through the column at a desired velocity.

15. • For industrial applications, upward flow is generally
preferred over downward flow because it does not
compress the beds in enzyme columns as downward
flow does. When gas is produced during an enzyme
reaction, upward flow is preferred.
• A continuous packed bed reactor has the following
advantages over a batch packed bed reactor:
• 1. Easy, automatic control and operation
• 2. Reduction of labor costs
• 3. Stabilization of operating conditions
• 4. Easy quality control of products

16. -5. Trickle-bed reactor

17. • The trickle-bed reactor is another variation of the
packed bed reactors.
• Liquid is sprayed onto the top of the packing and
trickles down through the bed in small rivulets.

18. A trickle-bed reactor (TBR) is a chemical
reactor that uses the downward movement of a liquid
and gas over a packed bed of catalyst particles. It is
considered to be the simplest reactor type for
performing catalytic reactions where a gas and liquid
(normally both reagents) are present in the reactor and
accordingly it is extensively used in processing plants.
Typical examples are liquid phase hydrogenation
in refineries (three phase hydrotreater) and oxidation of
harmful chemical compounds in wastewater streams.

19. - 6. Fluidized bed reactor

20. • When the packed beds are operated in upflow mode,
the bed expands at high liquid flow rates due to
upward motion of the particles.

21. Fluidized bed reactor (FBR) is a type of reactor device
that can be used to carry out a variety
of multiphase chemical reactions.
In this type of reactor, a fluid (gas or liquid) is passed
through a granular solid material (usually a catalyst possibly
shaped as tiny spheres) at high enough velocities to suspend
the solid and cause it to behave as though it were a fluid.
This process, known as fluidization, imparts many
important advantages to the FBR. As a result, the
fluidized bed reactor is now used in many industrial
applications.