Question

A continuous sterilizer with a steam injector and a flash cooler will
be employed to sterilize medium continuously. The time for heating
and cooling is negligible with this type of sterilizer. The typical
bacterial count of the medium is about 5×1012 m−3, which needs to
be reduced to such an extent that only one organism can survive
during the three months of continuous operation. The heat resistant
bacterial spores in the medium can be characterized by an Arrhenius
coefficient (kd0) of 5.7×1039 hr1 and an activation energy (Ed) of
2.834×105 kJ/kmol (Deindoerfer and Humphrey, 1959). The
holding section of the sterilizer will be constructed with 20 m-long
pipe with an inner diameter of 0.078 m. Steam at 600 kPa (gage
pressure) is available to bring the sterilizer to an operating
temperature of 125°C. The physical properties of this medium at
125°C are c =4.187 kJ/kgK and ρ =1,000 kg/m3, and µ = 4 kg/m hr.
a. How much medium can be sterilized per hour if you assume
ideal plug flow?
b. How much medium can be sterilized per hour if the effect of
axial dispersion is considered?

Answer 1

Answer:

Continuous sterilization is the rapid transfer of heat to medium through steam condensate without the use of a heat exchanger. ... So instead of having a cold-water stream cool the sterile media, the lower temperature unsterile media stream absorbs heat from the warm stream, cooling the sterile media.

•There are two types of continuous sterilizers- Indirect heat exchanger and Direct Heat exchanger or steam injectors. The inertial impaction, electrostatic attraction, interception are the types of Filter sterilization

•Steam is used to sterilize fermentation media. The medium can be sterilized in situ within the bioreactor. However, if the medium is sterilized in a separate vessel, the bioreactor needs to be sterilized before the sterile medium is added to it. Bioreactors are sterilized by passing steam through spargers.