Rev January.2012
0
Cleaning the product path
The product path of the heat exchanger system shall always be cleaned with lye
and/or acid
immediately
after a production cycle. The product path should be
sterilized immediately before the next production cycle commences.
Cleaning flow rate
The flow rate for cleaning the product path should always be at least (1.5 to 2) m/s.
Under normal conditions the CIP velocity should never be lower than the product
velocity. An increased cleaning flow rate may be necessary under certain
circumstances; for example in heat exchanger systems used for products that have a
tendency to burn on - such as milk, protein and sugar products.
Refer to the table presenting different velocities for different multitubes and
monotubes.
Cleaning agents
The following cleaning agents are recommended by Alfa Laval:
NaOH
A solution of (1-2)% by weight of NaOH at a maximum temperature of 70°C. Dissolve
1 kg of caustic soda in 100 lit. of water or mix 2.2 lit. of 33% NaOH solution in 100 lit.
of water.
HNO3
A solution of 0.5% by weight of HNO3 at a maximum temperature of 70°C. Mix 0.7
litres of 53% (36° Be) nitric acid in 100 litres of water.
I
n exceptionally severe cases such as milk sterilization plant, it is permissible to
exceed the concentrations specified above. However the cleaning recommendations
offered by Alfa Laval should always be observed.
Other detergents
In addition to caustic soda and nitric acid, detergents containing wetting and
complex-forming agents may be used also. However the maximum concentrations of
caustic soda and nitric acid stipulated above must be observed.
Detergents should be dosed gradually in order to avoid excessive local and
temporary concentrations; Hazardous agents must be handled according to local
demands.
Cleaning water
Clean water that is free of chlorides must be used for all cleaning solutions.
CIP cycles
Recommended cleaning intervals and the timing of the CIP cycles are shown in
Table below, where all times are given in minutes. Before commencing a CIP cycle,
ensure that no service media remain in the heat exchanger system. If necessary
drain the heat exchangers or, if the medium is steam, open a pressure relief valve.
