(an air-lift bioreactor with an internal loop, taken from a BASIC program written by Gregory Fieldson for a term project in 1988.)
Air-lift Bioreactors
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. The figure below illustrates the basic structure of an air-lift bioreactor with an internal loop.
(an air-lift bioreactor with an internal loop, taken from a BASIC program written by Gregory Fieldson for a term project in 1988.)
Please answer this question:
Which type of reactor is the world's largest industrial fermenter?
You answer must be: stirred tank reactor! But, you are wrong. A STR can never be very large because of the heat-exchanger, mixing and aeration problems. The world's largest fermenter is Air-life Bioreactor! These photos taken from Chemical and Engineering News show the largest bioreactor in the world. The fermenter is 200' high and 25 ft diam. The first photo (Chem. Eng. News, 10-Apr-78) shows the fermenter being transported on vehicles with tank treads.
The next photo shows the fermenter being raised into position at the ICI, Ltd. factory, Billingham, UK, (Chem. Eng. News, 18-Sep-78) :
Roca et. al. (Ref. 1) investigated a gas lift bioreactor
during a continuous alcoholic fermentation by using a strongly flocculating
yeast. The biomass concentrations got were between 85 and 110 g dry
weight/l. The bioreactor behaviour is completely homogeneous, except for
high substrate and biomass concentrations. Mixing times are very low, in
the order of 10 seconds.
Reference:
Last modify: 05/01/2000, by Xuezhen Kang