» Products & Technologies » Refining » Physical Refining
Our physical refining chiefly consists of pre treatment & bleaching, de acidification & deodorisation and fractionation. All these are advanced technologies undertaken by highly proficient workforce of our company. These are offered to our esteemed clients at reasonable price range.
Pre Treatment & Bleaching
The feed oil (acid conditioned, degummed / neutralized & washed) enters the Bleacher via a Bleaching heater where the oil is heated up to Bleaching temperature and discharged into the slurry mixer. A valve dosing system proportions bleaching earth. The earth is introduced under the oil spray in the mixing chamber for improved mixing so that earth does not enter the Bleaching Vacuum System. The earth adsorbs any residual gums and soap as well as trace metals, color bodies and other polar impurities. The Bleacher has multiple agitated compartments and operates under vacuum to ensure complete moisture and air removal. The dried oil and earth mixture is discharged by the Bleacher Discharge Pump to one of the Filters where the spent earth is removed. The filtered oil is collected in the Filtrate Receiver. The Bleached Oil Pump sends the oil to Deodorizing via one of the alternating Polish Filters.
Filter Management :
The standard bleaching system is based on the use of two filters of which one is on line while the other is being cleaned and prepared for the next cycle. When a filter has reached its maximum capacity, as indicated by high feed pressure, it is taken off line for cleaning and replaced by the other filter..
The cleaning procedure begins by first pressurizing the filter with steam to expel residual oil into the Recovered Oil Tank and dry the spent filter cake. The oil recovered from the filter cake is collected in the tank and can usually be recycled to the Bleacher. After drying, a bottom discharge valve on the filter is opened and the leaves pneumatically vibrated so that the spent cake is dislodged and discharged via a hopper. The filter is then closed and readied for the next batch. Before going on line again it can be pre-coated with filter aid and/or bleaching earth in order to seal the filter leaves and minimize clogging. The adsorbents are mixed with bleached oil in the Precoat/Heel Tank and applied to the leaves by circulation with the Precoat Pump. When not using filter aid or “off-line” pre-coat, the empty clean filter is filled and put on line while the other filter is still in operation. The filtrate from the clean filter is recycled back to the Bleacher until the filter is pre-coated with bleaching earth and the oil is clear. After this the full flow is switched to the new filter.
De Acidification / Deodorisation
Bleached oil is continuously pumped from the Feed
Tank by the Deareator Feed Pump. The oil is pre-heated in the Deaerating
Economizer by outgoing deodorized oil followed by the Deaerating Heater (if
necessary) before entering the Deaerator. The vessel is under full vacuum,
so that residual air is reduced to an absolute minimum. The Deaerator
Discharge Pump sends the oil through a Heat Economizer where the temperature
is increased by hot deodorized oil. The oil is heated to full processing
temperature in the Vacuum Heater by thermal fluid from the Thermal Oil
Heater. A portion of the free fatty acids in the oil will be flashed off in
The hot oil enters the Packed Column, which is filled with special
structured packing so that the oil is distributed into a thin film and is
evenly agitated by stripping steam flowing counter currently from the bottom
of the column. As a result, free fatty acids and other remaining volatile
impurities in the oil are evaporated and removed with the steam. The
residence time in the column is only a few minutes. The bulk of the free
fatty acids along with aldehydes, ketones etc. in the oil are quickly
stripped off before any heat induced permanent damage has been done.
The stripped oil from the column flows into the
Deodorizer where it flows through the channels of a series of vertically
stacked compartments (trays) while agitated by stripping steam. The
prolonged thermal action breaks down carotene and other color bodies,
resulting in a lighter oil color. Also, the amount of remaining free fatty
acids in the oil is reduced to an absolute minimum. The stripping steam
passes through the packed column and no separate steam is required in the
stripping column. The maximum retention time in the Deodorizer is 70
The deodorized oil is discharged by the Product Pump and
further cooled to storage temperature in the Deodorizing Economizer ,
Deaerating Economizer, Bleaching Economiser and Product Cooler. The
anti-oxidant is mixed with oil in the Deodorizer. The finished oil is
finally sent to storage via one of the alternating Product Filters.
Distillate Recovery :
Fatty acids and other materials, evaporated
from the oil, are condensed by contact with recycled and cooled distillate
in the Vapor Scrubber. The distillate is circulated by the Distillate Pump
via the Distillate Cooler where it is cooled by cooling water. Accumulated
distillate is discharged from the Scrubber to storage.
Trans and Tocopherol :
The high efficiency (low amount of stripping
steam) and short retention time of the stripping column, combined with the
possibility to reduce the heat bleaching time or temperature, ensure optimum
conditions for controlling the process. The oil can thereby be properly
deodorized without the creation of trans fatty acids while also controlling
the amount of tocopherol removed from the oil
Protection Against Air Contamination :
For optimum quality,
especially when processing unsaturated oils, the oil should be protected
from air contamination during the entire deodorizing process. The packed
column type Deareator ensures maximum removal of dissolved air before high
temperature heating. This also helps minimize polymerization of the oil on
the inside of the heat exchange coils of the heat Economizer.
Process Control :
The control, operation and supervision of the
plant can be handled by one operator per shift. All main process parameters,
if required, e.g. flow rates, temperatures, liquid levels etc. are
automatically maintained from a control panel or, as an option, with the
help of PID/PC based controls.
The homogeneous batch of RBD palm oil is
transferred from storage by the Crystallizers Feed Pump and heated to 75-80C
in the Oil Heater while loading one of the Crystallizers. This procedure
assures an oil free of crystals, which would affect the selective
crystallization of the different triglycerides in the oil.
When the oil transfer has been completed in a Crystallizer, the cooling
process is started. A slow rate of chilling is essential in palm oil
fractionation and so the entire cooling process is programmed through the
microprocessor programmable controller, to accomplish this critical mode of
operation. The controlled cooling permits the adequate nuclei formation,
further crystal growing, and final crystal maturation for a satisfactory
separation of olein and stearin. During the complete cycle, a slow agitation
by means of a variable speed, multi-stage, flat blade turbine Agitator keeps
the crystallized mass suspended and in constant movement, achieving a
uniform crystallization and an efficient heat transfer through the series of
In the fractionation system, the coolant is supplied to the Crystallizer at
a temperature always within a few degrees of the oil temperature to insure
slow and controlled crystallization inducing large and even crystal growth.
To minimize energy cost, fractionation cooling is done in two steps: In the
first stage Cooling Tower water is circulated in the Crystallizer coils,
thereby saving energy. In the second cooling stage chilled water from the
Chilled Water Tank is pumped with the Chilled Water Pump at the required
controlled rate to the Crystallizer, thus required amount of chilled water
is added to a stream of warmer water in constant circulation by the
Crystallizer Water Circulation Pump through the cooling coils.
After completion of the oil crystallization and subsequent maturation of
the crystals, it is very important that the proper final fractionation
temperature (16 to 24 C) is achieved before filtration of the crystallized
mass in order to assure the required cloud point in the filtered olein. A
Diaphragm (membrane) Filter Press is used for the separation of high quality
olein and stearin.
The Diaphragm Filter Press operates on a semi-continuous basis. The filters
successive operation during its cycle is the following: cake formation, cake
squeezing and cake discharge. Twice a day the filter clothes are washed by
hot olein circulation. The filter is also cooled with cold olein before
starting a new filtration cycle after the washing step. The crystallized
slurry to be filtered is fed continuously by the Filter Feed Pump into the
filter. A frequency inverter in the pump is used to control the filter
pressure. Filtrate liquid (olein) is discharged to the Olein Receiver, and
then pumped out to the storage tank by the Olein Pump. When a filtration
cycle is completed the Filter Feed Pump stops and the stearin cake is
squeezed by the pressurized diaphragms, thus separating the remaining olein.
The filter plates are then opened and the cake falls by gravity to the
Stearin Tank where it melts and the Stearin Pump pumps the liquid stearin
out to the related storage tank.
Two refrigerant based Water Chilling Packages are supplied to maintain the
chilled water temperature in the 5 to 10 C range. The Chiller Pump is used
to keep the water closed loop from the Chilled Water Tank and the Chiller
evaporator. The refrigerant gas compression and latent heat is removed in
the Chiller condenser by the cooling water from the Cooling Tower, which is
circulated by the Cooling Water Pump. The Cooling Tower is also used to
pre-cool the palm oil in each Crystallizer cooling cycle.
Process Control :
The control, operation and supervision of the plant can be handled by one
operator per shift. All main process parameters, if required, e.g. flow
rates, temperatures, liquid levels etc. are automatically maintained from a
control panel or, as an option, with the help of PID/PC based controls.