This document discusses calculating the sterilizing temperature required for a continuous sterilizer pipe. It provides the flow rate and bacterial spore concentration of the medium, as well as the activation energy and Arrhenius constant for thermal destruction of the contaminants. It also gives the pipe's inner diameter, holding section length, medium density and viscosity. The goal is to determine the sterilizing temperature that provides an acceptable contamination risk of one surviving organism every 60 days of operation.

1. Hint: so, need to find out X (i.e. how long) and radius (r),
The cross sectional area of the filter (πr2) = volumetric air flow rate/linear air velocity

3. Problem
Medium at a flow rate of 2 m3 h-1 is to be sterilised by heat exchange with steam in a continuous steriliser. The liquid
contains bacterial spores at a concentration of 5*1012 m-3; the activation energy and Arrhenius constant for thermal
destruction of these contaminants are 283 kJ g mol-1 and 5.7 x 1039 h-1, respectively. A contamination risk of one
organism surviving every 60 days' operation is considered acceptable. The steriliser pipe has an inner diameter of 0.1 m;
the length of the holding section is 24 m. The density of the medium is 1000 kg m-3 and the viscosity is 3.6 kg m-1 h-1. What
sterilising temperature is required?

4. Re – Reynold’s number
D – pipe diameter
u – fluid velocity
µ - viscosity
ρ - density
πr2
For Re= 7.07 x 103 we can determine Dz from Figure 13.40 using the experimental curve (this
data/graph is generally given or obtained from experiments)
0.1

5. Da = 42
The sterilisation temperature can be evaluated after rearranging Eq.

6. Hope you all understand it