For deodorization and physical refining of fats and oils0 pages

For deodorization and physical refining of fats and oils
Stripping Column
Application
This high-performance packed stripping column is specially
designed for deacidification and deodorization of fats and oils
in refining plants. The stripping column is a part of the
Alfa Laval SoftColumn™ deodorizing concept, but can also
be offered as a retrofit component for other deodorizers –
irrespective of make.
Working principle
The pre-treated and heated oil flows either by gravity or under
pressure from the final heater to the distributor on the top of
the column. The distributor spreads the oil evenly over the
cross-section of the column. This oil then trickles down the
structured packing, flowing as a thin layer on this extended
surface until it reaches the bottom of the column. It then continues
to the next process step. The counter current flow of
the steam is achieved via a steam distributor installed in the
bottom of the column or from another source. The oil in the
column meets the stripping steam in a counter current flow.
The column is under vacuum, so exposing the oil to the vacuum
at a high temperature removes volatile substances and
the steam carries them out to the vacuum outlet at the top of
the column. The height of the column is a function of the
number of desired distillation steps.
Design features
Volatile compounds, such as fatty acids and various odor
causing compounds, are distilled off by the joint action of the
vacuum and the stripping steam. The extensive surface area
created by the structured packing and the counter current flow
regime in the column significantly reduces the amount of stripping
steam needed, compared with the traditional tray system.
The short retention time inside the column and the reduced
amount of steam means the oil is treated gently. Due to low
retention time at high temperature, low amount of steam and
fast distillation effect, unwanted or side reactions are reduced
to a minimum. The packing is specially designed with a low
static hold-up and rapid draining properties. This keeps the
level of contamination during stock changes within the
desired limits.
Due to the special design of the packing, which creates turbulence
between the plates, and the fact that there are no
stagnant zones, a self-cleaning effect ensures continuous
operation.
The flexibility of the system keeps the formation of trans-isomers
within acceptable limits, and allows for the removal or
retention, of natural antioxidants, while maintaining high quality
of the oil.
The stripping section allows for the independent operation of
distillation, so that process conditions can be modified for different
oil stocks and quality requirements without compromising
other important factors.
In order to simplify service and maintenance, if the column is
supplied with the sparge steam tubes, they can be removed
from outside for manual cleaning. The inside of the column is
accessible for assembling the packing and for maintenance.
The column can be supplied with two manholes, one at the
top and one at the bottom, with illuminated sight glasses with
double O-rings on the flanges.
Installed stripping column