Bioprocess Bioreactor designs

TEKNOLOGI BIOPROSES

Bioreactor Design Properties

1

• Mass Transfer

2

• Heat Transfer

3

• Dimension

4

• Power consumption

5

• Hold Up

1

• Mass Transfer

Determine K_La

α is proportionality factor, 2x10^-3

2

• Heat Transfer

The reaction in bioreactor, especially fermentation:

generate HEAT

 Need cooling (coils or jacket in vessel)

Conduction

single layer

multi layer

Convection

Natural Forced

x kA T

q

_x ^{ }_

T

q

_x ^ hA^

3

• Dimension

1. Reactor volume 2. Reactor diameter

3. Ratio of reactor diameter to impeller diameter D_t/D_i

4. Ratio of the height of the liquid level to impeller diameter, H /D

4

• Power consumption

Power consumption per unit volume of liquid

Power consumption:

5 3

i c

p N D

N Pg

 

c i p

g

D N P N

5

 3



N_P is a function of Re and type of impeller Use graph

N = rpm/60 = ... rps

Correction factors are used to define actual power

P_act = P. F_c. number of impeller

There is a further discussion for aeration power

(next subject)

5

• Hold Up

 Assume air in water

Ykcal

C V

q 1







 



Heat production rate:

q : heat production rate, kcal/ls

V: reactor liquid volume, l

: specific growth rate, s^-1

C: biomass concentration (g/l) Y_kcal: a yield coefficient given as

grams of cells formed per kcal energy

Heat load: Heat load is determined by energy balances Practical Issues for Bioreactors

- Temperature Control (Heat Load)

Popular method

-Temperature control (heat transfer)

Heat transfer surface area:

1. Low in (a) external jacket and (b) external coil for small reactors

2. High in (c) internal helical coil and (d) internal baffle coil for large reactors 3. Easily adjustable in (e) a separate external heat exchange unit

Difficult to clean Easily fouled by cell

growth on the surface

No cleaning problem

• Sterility

1. Biological reactions almost invariably are three-phase

reactions (gas-liquid-solid). Effective mass transfer between phases is often crucial. For example, for aerobic

fermentation, the supply of oxygen is critical.

H P

CA^*  Ag



A A_g



l

A

K C C

J 

^*



The equation governing the oxygen transfer rate is:

Agitation:

•Mechanical stirring (for small reactors, and/or viscous liquids, low reaction heat)

•Air-driven agitation (for large reactors and/or high reaction -Agitation (gas transfer)

1. Mechanical foam breaker (a

supplementary impeller) 2. Chemical antifoam

agents (may reduce the rate of oxygen transfer) - Foaming removal

2

1. Aseptic operation (3-5% of fermentations in an

industrial plant are lost due to failure of sterilization.

2. Construction materials (glass for small bioreactors, e.g., < 30 liters and corrosion-resistant stainless steel for large reactors)

3. Sparage design (three designs: porous, orifice and nozzle)

4. Evaporation control due to dry air input - Other issues

Nur Istianah-THP-FTP-UB-2017

THANKS FOR YOUR ATTENTION

The best person is one give something useful always