Up - Upscale

Question 1

[Upscale] What is the #1 parameter to keep constant?

Answer 1

1: Geometry (height, stirrer - mixing and OT)

Question 2

[Upscale] What is specific power input (P/V)?

Answer 2

How much power transferred to the liquid by the action of the mixer. Dependent on rate of stirring, size and shape of stirrers, and the viscosity.

Question 3

[Upscale] Which parameters are related to mixing?

Answer 3

Mixing time: Longer time to distribute

Power input per volume: Power from the mixer (also increase OTR)

Agitator tip speed: Shear rate produced from the impellers (constant? lower P/V)

Viscosity: Distribution of the shear rate (average low, maximum high)

Question 4

[Upscale] Which parameters are related to gas transfer?

Answer 4

kLa: OTR, depends on geometry, mixing and gassing

Aeration rate: Volume of gas flow per bioreactor per minute (vessel volume per minute (VVM))

Superficial gas velocity (vs): Volume of gas per cross-sectional area of the reactor (how fast go through)
- Increase? More foam, less P/V (viscosity), more OT

Question 5

[Upscale] How is the temperature regulated at large scale?

Answer 5

Distribution of heat - need internal coils for temperature regulation (area per volume decrease). Also cool down.