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The Pennwalt
Continuous Bleaching Process
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The neutral, washed and dried Vegetable Oil still contains some
colour bodies and small traces of soap (<50 ppm) which have to
be removed.
The Pennwalt Continuous Bleaching Plant equipped with hermetic
leaf filters, operates under vacuum to prevent oil oxidation.
The oil is cold mixed with metered quantities of bleaching earth
and/or other bleaching agents and thereafter heated to the correct
temperature and pumped to the Continuous Bleacher operating under
vaccum where an adequate retention time is provided to ensure
effective bleaching. The oil earth slurry is further pumped to
two hermetic leaf filters operating sequentially resulting in
continuous bleached oil (filterate) discharge.
Advantages:
Cuts costs on labour, maintenance, spares and bleaching earth.
Proportions bleaching earth to oil or fat, continuously and
accurately.
Optimum conditions of vaccum temperature and dryness of both
components facilitates efficient deaeration and degassification
of the oil-earth mixture.
Minimises operator attendance by fully automating the process.
Capacity
Pennwalt continuous Bleaching plants are available for plant
capacities of 50 TPD and above. For capacities below 50 TPD,
batch bleaching process is recommended.
Deodorisation
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The deodorisation process is highly specialised type of steam
distillation under high vacuum based upon the principle of
falling film to remove objectionable volatile components such
a ketone, aldehydes, alcohols. The bleached oil is pumped
by the feed pump to the deaerator where the pretreated oil
is degassed. This deaerated oil is passed through a heat exchanger
where the oil is heated by exchanging the heat of the deodorised
oil. The oil is further heated to the stripping temperature
in the preheater wherein thermic fluid is circulated. The
above oil is fed to a flash chamber and flows thereafter to
an oil distributor inside falling film deodoriser. The oil
descends counter current to the stripping steam in the form
of very thin film and gets completely deodorised. The fatty
acids distilled are condensed, cooled and stored.
The oil from the bottom flows to an intermediate vessel having
an arrangement for dosing citric acid. This deodorised oil
is then pumped through a heat exchanger to the polishing filter.
The filtered oil is thereafter passed through a cooler and
discharged for collection.
Advantages of Falling Film Technology are as follows:
Short hold up time during deodorisation compared to any conventional
deodorising plant. The hold up time is approximately 30 secs.
compared to 90-130 minutes.
Deodorisation takes place inside the tubes from a thin film
of less than 0.3mm thick. Thus there is a good heat as well
as mass transfer, without any significant pressure drop.
This plant can process heat sensitive oils without ester interchange
effects.
Due to short hold up time at high temperature and under high
vacuum, there is no colour fixation of oils.
Due to low pressure drop the stripping steam consumption is
approximately 110 kgs/ton of oil which is much lower than
that of conventional plants giving approx. saving on steam of
30 to 40%.
The energy consumption of the vacuum plant is essentially
reduced because a lower amount of stripping vapour has
to be sucked off.
The counter flow configuration of the falling film deodoriser
results in lower entraining loss of oil.
There is a lower water demand in the vacuum equipment due
to size reduction.
Fuel oil consumption is less as compared to conventional Continuous
Deodoriser.
Fat Splitting
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In fat splitting or hydrolysis, vegetable or animal fats are
split into fatty acid and glycerine, merely by addition of
water. The Pennwalt one-tower fat splitting process employs
highly innovative and advanced technology for continuous fat
splitting without a catalyst. The splitting takes place at
a high (55 Bar) pressure in presence of water. The fat and
water flow in opposite directions, resulting in high glycerine-water
concentration and low-steam consumption. The Pennwalt One-tower
splitting plant is totally continuous, designed so that the
fat is pumped in and the fatty acid and glycerine water pumped
out-continuously. The plant is totally automated and its operation
switch-button simple. All control instrumentation is connected
to the switchboard making it possible for just one operator
to supervise the splitting plant.
Advantages:
Minimum steam consumption (approx. 200 kg/ton of fat) achieved
by heat exchange in the splitting tower.
High glycerine-water-concentration (with a ffa-content of
5% in the crude fat, the glycerine-water-concentration
is approx. 20%) made possible by the specially designed water
distribution system inside the tower top.
Discharge of fatty acids from the plant at approx. 80OC.
Switch-button simple and continuous operation.
The Pennwalt Fatty Acid Distillation Process
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here to view the process
Distillation of heat sensitive fatty acids is a highly complex
and difficult operation requiring specialised process and
equipment. Developed after years of research and experimentation,
the Pennwalt / Schmidding Werke fatty acid distillation process
is the most efficient, state-of-the-art process available
in the world today, for the distillation of fatty acids obtained
from high pressure splitting. It is specially designed to
obtain premium quality fatty acids, free from odours and low
molecular weight components and minimum colour contaminants,
with the help of a pre-run column. The process involves stripping
the maximum amount of unwanted volatiles from the fatty acids.
EQUIPMENT
The Plant consists of a de-gassing and de-watering stage,
complete with a condensor/gas cooler and a condensate receiver,
two pumps, a pre-run column with falling film evaporator,
a product pre-heater, one reflux condensor, two other condensors,
the main distillation column with a falling film evaporator
and a residue stage falling film evaporator, a condensor serving
as a product pre-heater for the de-gassing and de-watering
stage, a final condensor, a gas cooler, a residue cooler,
a distillate receiver and three pumps.
PROCESS DESCRIPTION
The colour and odour carriers of split crude fatty acids-secondary
components, mainly created by oxidation and decompositon with
a much lower boiling point - are drawn off together with the
fatty acids in the de-gassing / de-watering stage, mainly
with the stripping steam added to the bottom. The fatty acids
are then continuously fed to the pre-run column, where most
of the remaining secondary components, the odour and colour,
are removed by steam distillation. The deodorisation of fatty
acids, and the separation of odour and colour components is
effected by the addition of steam to the bottom.
The fatty acids from the bottom are pumped back partially
to the column through a falling film evaporator, where the
temperature is raised to above 200OC by heating
with thermic fluid. The reflux is brought about by the reflux
condensor. The control is effected via circulation water.
The odour and colour material moves to the next condensor
due to initial cooling by the reflux condensor. The vapours
entering the next two condensors help obtain maximum recovery
from the first running separated in the liquid phase separation
tank.
The fatty acids from the pre-run column are fed into the distiller
column. The acids from the bottom of this column are then
pushed back partially through the column via the falling film
evaporator, where the appropriate temperature to achieve the
maximum rate of evaporation inside the distiller column is
maintained. The distilled fatty acid vapours leaving the column
transfer heat partially to the crude fatty acid in a condensor
and then enter the next condensor, where the maxinum recovery
of the distilled fatty acids is effected. These are then collected
in the distillate receiver. The necesary reduction in the
temperature of the distilled fatty acids is achieved with
the help of the distillate cooler.
As the level inside the distiller column increases the fatty
acids from the bottom of the column are pumped into the residue
falling film evaporator, which are then fed back to the distiller
column. With an increase in the falling film evaporator level,
the accumulated residue is then discharged and after proper
cooling in the residue cooler, conveyed to residue storage.
ADVANTAGES:
OF FALLING FILM TECHNOLOGY FOR PRE-RUN AND DISTILLATION
OF FATTY ACIDS
The pre-run improves the quality of the distilled fatty acids
by getting rid of low molecular weight fatty acids, odorous
material and colouring compounds.
The evaporation takes place inside the tubes from a thin liquid
film, usually less than 1 mm in thickness, resulting in good
mass transfer with minimum pressure drop.
The device requires only small effective volumes, as the tube
wall is heated immediately.
The formation of the film takes place under the influence
of gravitational force.
Heating is achieved by a falling film evaporator, where highly
effective heat transfer is obtained with very short liquid hold-up
times in the tube.
Falling film evaporators need minimum maintenance.
Best for heat sensitive fatty acids.
The unique design of the plant makes the process totally reliable.
OF PENNWALT VEGETABLE OIL PLANTS
Pennwalt plants are easy to operate and require very little
space.
The Pennwalt Glycerine Distillation Process
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Over the years, the demand for Glycerine in India, has continued
to grow, far outstripping the supply. It's a highly strategic
chemical, used in the manufacture of explosives, pharmaceuticals,
foods, paints, chemicals and dyes. All-out efforts are therefore
being made to bridge this gap between supply and demand by
increasing the present fatty acid industry capacity, and also
to step up the production of glycerine in India. Considering
the vital role of glycerine in the Indian Industrial sector
it is of utmost importance that the very latest, state-of-the-art
technology should be used in it's manufacture.
The Pennwalt / Schmidding Werke Glycerine distillation process
and plant is just that - the most modern technology available
in the world today.
THE PENNWALT / SCHMIDDING WERKE GLYCERINE DISTILLATION
PROCESS
Glycerine distillation is a highly complex problem requiring
specialized equipment and processes. Developed after years
of research and development work. The Pennwalt / Schmidding
Werke Glycerine distillation process is one of the most efficient
and economical processes available in the world today, offering
significant advantages to glycerine distillers. It is designed
for the distillation of the Glycerine / Water mixtures (with
a glycerine concentration of 85-95%) obtained from multi-stage
evaporation.
During the continuous glycerine distillation shown in the
flow sheet, the lower boiling components are removed from
the glycerine in a first runnings column, which also improves
colour and odour. In a second stage, the glycerine distillate
is obtained in its desired concentration, and the residue
is separated.
This operation ensures the extraction of glycerine distillates
of the highest purity. Depending on the quality of the new
material, a chemical treatment is provided when the material
enters the distillation kettle. This permits a precipitation
of additives which would otherwise have had a negative influence
on the quality of the glycerine. The extreme sensitivity of
glycerine to thermal loads is moderated both by the use of
falling film evaporators covering the entire heating area
with a product film and by applying a low operating pressure
and correspondingly low evaporation temperatures. Besides,
flanged joints are used providing the possibility of additional
seal welding. With reduced vacuum, the glycerine first runnings
are then separated and collected in separate receivers, as
is done with the glycerine tails received later on, and fed
back to the charge tank to increase the yield of glycerine.
The extraction of pure glycerine at careful thermal treatments
is also assured by the use of column packings of low pressure
drop, enabling a very low pressure drop between the vacuum
pump and the distillation kettle.
PROCESS DESCRIPTION
The feed concentration of crude glycerine is normally 85%
to 90%.
The feed picks up heat from outgoing vapours from the main
distillation column and enters the pre-run stage, where the
first runnings are separated by steam distillation. The glycerine
from the bottom of this column is then pumped back to the
column via the falling film evaporator where the appropriate
temperature is maintained. The distilled glycerine vapours
leaving the column transfers heat partially to the feed, and
then enters the condensor where maximum glycerine recovery
is obtained. With an increase in the glycerine level, the
residue is discharged from the distiller bottom.
The process includes de-watering and distillation stages.
If a residue stage is provided at the end of the process,
the glycerine is pumped from the bottom of the main distillation
column into the falling film evaporator of the residue stage.
It is then distilled, condensed and taken back to the pre-run
stage. The arrangement of the process equipment as shown in
the flow diagram, represents a specific case only, and will
vary depending on individual requirements.
ADVANTAGES:
OF THE PENNWALT / SCHMIDDING WERKE GLYCERINE DISTILLATION
PROCESS
The Pennwalt / Schmidding - Werke process offers glycerine
manufacturers and distillers the following significant advantages
A totally continuous and economical process; thus there is
no money lost due to plant shut-off and
the resultant downtime.
The extraction of glycerine distillates of the highest quality
and purity.
Ready marketability.
Higher profitability.
Switch button simple operation.
Simple and easy maintenance.
Batch distillation (semi-continuous distillation) is available
where continuous operation is uneconomical.
OF PENNWALT VEGETABLE OIL PLANTS
Pennwalt plants
are easy to operate and require very little space.
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