Reactor Design

Question 1

which ingredient can be used to increase the yield of penicillin by 10 fold?

Answer 1

corn steep liquor

Question 2

which ingredient is used to produce more antibiotic

Answer 2

lactose

Question 3

corn steep liquor key points

Answer 3

waste product of corn wet milling process
rich in AA
clean corn is soaked in water containing lactic acid & S02
for 40 hours approx. liquor Is then filtered, then concentrated using evaporators
used in fermentation media & animal feels

Question 4

materials used for reactor design

Answer 4

wood, plastic, glass, metal, stainless steel

Question 5

considerations when designing a reactor

Answer 5

cost, ease of construction, durability, cleanable, sterilisable, ease of use

Question 6

reactor shapes

Answer 6

square, cylindrical with flat ends, cylindrical with domed ends, spherical

Question 7

problem with square reactors

Answer 7

harder to clean since there are corners

Question 8

spargers?

Answer 8

used for O2 transfer. sparers can be open tubes, perforated tubes and single point or ring design with multiple outlets

Question 9

bubble size vs mass transfer

Answer 9

smaller bubbles, larger SA, better mass transfer

Question 10

air in fermenters

Answer 10

air supplied into a fermenter has to be sterile . air filters used to be metal cylinders packed with glass wool. now made from polymers like PTFE and have a defined pore size

Question 11

impellers?

Answer 11

cut through water. if hits a bubble, there will be shear. when there is shear we have the capacity to reduce bubble size, increase mass transfer

Question 12

baffles?

Answer 12

for a stirred tank system, if baffles aren’t present, water will just vortex around tank. poor mixing, no shear. therefore add baffles to tank to prevent vortex.

Question 13

types of impellers?

Answer 13

flat blade disc turbine (RUSHTON TURBINE), propeller, pitched blade turbine, anchor, gate anchor, helical screw.
first 3 are used for active flow. high shear from flat blades.
last 3 are used for viscous flow

Question 14

viscosity in liquid fermenters?

Answer 14

low viscosity so impellers used are flat bladed turbines & propellers

Question 15

impeller design

Answer 15

operated at high rates. as rotational velocity increases, there is a lot of shear on the edges of flat blades.

Question 16

if sparger is present below rushton turbine…?

Answer 16

bubble size will be dependent on rotational velocity of turbine. if speed of turbine increases, better mixing of bubbles but bubble size decreases due to shear force

Question 17

impeller designed for mixing?

Answer 17

axial flow impeller

Question 18

reactor design scale up?

Answer 18

increase the number of turbines

Question 19

stagnant zones?

Answer 19

depending on viscosity of solution, we can get stagnant zones. if stagnant zones are present, biomass will use up 02, will go anaerobic.need to consider whether fluid in reactor is Newtonian or non- newtonian.