EXPERIMENT No.
2
DRY FRACTIONATION of RBD OIL
1.0 INTRODUCTION
The dry fractionation plant in Appendix l is used to separate the palm olein and palm stearin
from the RBDPO produced by physical treatment. The RBDPO is passed through the further
fractionation process to get various grade of palm olein and palm stearin. Usually, there are
three types of olein are produced:
(1) normal grade olein,
(2) super grade olein and
(3) olein with cloud point 7 - 8°e.
2.0 PROCESS DESCRIPTION
2.1 Crystallization Process
Firstly, the RBDPO feed must pass the quality specification, color <2.6R and FFA< 0.075 is
fed into the heat exchanger. The RBDPO feed is heated up by hot waters around 75°C. After
that the oil is kept homogenized at about 70°C in homogenizes before the start of
crystallization. The idea is to destroy any crystals present and to induce crystallization in a
controlled manner in the crystallizer.
After that, the oil is pumped to the crystallizer (Appendix 2). The crystallization
system is a batch type and is equipped with special crystallizers operating alternatively. These
crystallizers are made up of vertical cylindrical vessel full of thermo-regulated water which
submerged barrels containing the oil to be fractionated: each of these barrels is fitted with a
mechanical agitator. An automatic station controls the temperature in the various
crystallizers.
The crystallization process is carried out to remove the higher melting glycerides
which cause liquid oils to become cloudy and more viscous at low temperature. There are 3
factors (temperature, time and agitation), have a fundamental importance on the formation
and character of the crystal:
1. The lowering of temperature causes, because of supersaturating the higher melting
component to separate from a solution.
2. Agitation facilitates the formation of small crystals.
3. Time with a gradual decrease in temperature and stillness, promotes the formation of
longer crystals.
2.2 Filtration Process
After the crystallization process, the slurry from buffer tank passes through the filtration
process for the physical separation (Appendix 3) between RBD palm stearin and RBD palm
olein. Presently, the membrane filter is used for this filtration. Another alternative for this
purpose is by employing drum filter for separation. The membrane filter is pressure filter
1
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
where the filter pack comprising alternatively plates and frames, or a series of chamber is
compressed between one fixed and one movable cover or bulkhead. The filter media are
located between each individual element. Cake will build up in the hollow space between the
elements and fall out of the press when the filter pack is opened. Composition of the filter
pack is by means of electrically driven hydraulic system (75 bar), which controls the entire
mechanical parts of units, head plates, filter plates, plate shifting device with the built in
panel board.
3.0 METHODOLOGY
3.1 Plant Description
The dry fractionation pilot plant is used to produce a liquid fraction (olein) and a solid
fraction (stearin) from palm oil through crystallization and filtration. The pilot plant is
designed for batch processing at a capacity of 12 kg/batch and comprises the following main
components (refer to flow sheet R225P022 for tag number and description):
1. Crystallizer with agitator and cooling coil.
2. Filtration system with filtration pump and membrane filter press.
3. Olein discharge pump and stearin melting tank.
4. Chilled water system and hot water system.
3.2 Plant Operation
1. The following raw material, preheated to 45°C, is required:
a) RBD palm oil with( IV value range of 50-55) in storage tank T704
2. The following utilities are required:
a) Tap water for chilled water system and hot water system.
b) Steam at 2 barg for stearin melting.
c) Compressed air at 5 barg for control valve and cake squeezing.
3. Fill the chilled water tank with tap water and switch on the packaged chiller unit to
produce chilled water at about 10°C.
4. Fill hot water tank TIl3 with tap water and switch on electrical heating element
HTIl3 to produce hot water at about 90°C. Set the water temperature at
temperature controller TIC 113.
5. Set the cooling program for crystallizer TIll at temperature controller TIC 111.
6. Start pump P704 (located at the storage tank area) and feed oil from the storage tank
to crystallizer TIll. At high level HLAIIl, stop pump P704 and start mixer AG 111.
Use the frequency inverter to adjust the mixer speed.
7. Starts pump PlIO and circulate water in the cooling coil of crystallizer TIll. Set the
water temperature (80-85°C) at temperature controller TIC Ill.
8. Start pump P113 and feed hot water from hot water tank TIl3 to the cooling coil of
2
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
crystallizer TIll to heat the oil to about 70°C. Maintain the oil at this temperature
and under agitation for at least 10 min to melt and homogenize the oil.
9. At the end of the homogenizing time, start the cooling program at temperature
controller TIC 111. Switch over pump P1l3 to the chilled water tank and feed chilled
water to the cooling coil of crystallizer TIll to cool the oil according to the cooling
program.
10. At the end of the cooling program as indicated by the end-of-cycle alarm, the oil
in crystallizer TIll is ready for filtration.
11. Close filter FIll, start pump PIll and filter the oil through filter FIll. The liquid
fraction (olein) flows into olein tank TI14 while the solid fraction (stearin) forms a
cake in the filter chambers. The filter chambers are full when the feeding
pressure reaches 2 barg.
12. Stops pump PIll and start squeezing the stearin cakes by feeding compressed air
to filter FIll and inflating the rubber membranes. Olein trapped in the stearin
cakes is squeezed out and flows into olein tank T 114 thus drying the stearin
cakes.
13. After squeezing, release compressed air in the squeezing lines into the feed
channel (core) of filter Fill to blow the feed channel (core) clear of oil. Open the
pressure release valve of filter Fill to further reduce the internal pressure to zero
(atmospheric).
14. When it is confirmed that there is zero pressure in the feed and squeezing lines,
release the hydraulic closing pressure and open filter F5ll. Remove the stearin
cakes from the filter chambers and drop them into stearin tank T1l5. Start steam flow
to the internal heating coil of stearin tank TIl5 to melt the stearin cakes.
15. Repeat filtration (Steps 11 to 14) if there is still oil in crystallizer TIll.
16. When crystallizer TIll is empty, stop mixer AGlll, pump PlIO and pump P113.
Switch off the packaged chiller unit and electrical heating element HTI13. Stop
the temperature controllers.
17. Starts pump P114 and transfer the oil in olein tank TIl4 to the next processing
stage. When olein tank TIl4 is empty, stop pump P114.
18. Open the drain valve of stearin tank TIl5 and transfer the oil to the next processing
stage. Stop steam flow.
19. Empty the pipelines by opening the drain valve at the pump.
3
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
Set your recipes based on diagram below:
Table of data:
Segment 1 Segment 2 Segment 3
Starting set point
(SSP1) in oC
Target set point
(TSP1) in oC
Time in minutes
3.3 Description
The quality parameters normally monitored for fractionation is Iodine Value (IV). By
definition, iodine value is the number of centigrams of iodine absorbed per gram of sample.
While the method provides good accuracy and precision when applied to normal fatty acids,
analysts must be careful to follow procedures exactly, as small deviations in sample size,
reagents and time of reaction will definitely affect the accuracy and precision of the method.
IV represents the degree of saturation of an oil or fat. Lower IV means the oil is of high
saturation and vice versa. Normally the IV for RBD paIm oil is 52 and IV for palm olein is
56. The efficiency of the plant is measured by the production yield.
The yield is calculated as:
Production Yield = Weight of olein produced x 100%
Weight of RBDPO feed
4
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
The yields for fractionation plant producing RBD palm olein from RBD palm oil normally
between 78% to 80%. Many times in continuous running plant, the yield cannot be measured
by weight basis.
4.0 ANALYSIS
4.1 Iodine Value
Theory:
The iodine value, IV expressed in grams per 100g of fats by the equation:
Iodine Value, IV =
Where,
C is the concentration of the sodium thiosulphate solution (mol/L)
V1 is the volume of sodium thiosulphate solution used for blank sample (ml)
V2 is the volume of sodium thiosulphate solution used for the determination (ml)
M is the mass of the test sample (g)
Apparatus:
Glass weighing scoops
Conical flasks, 500 ml capacity fitted with ground glass stoppers and
completely dry.
Analytical balance
Reagents:
1. Potassium iodide (KI), 100 g/L not containing iodate.
2. Starch solution
Mix 5g of soluble starch in 30 ml of water and add to 1000 ml of
boiling water.
Boil for 3 min and allow to cool.
3. Sodium thiosulphate (Na2S2O3.5H2O), standard volumetric solution, c = 0.1M
4. Solvent, prepared by mixing equal volumes of cyclohexane and glacial acetic
acid.
5. Wijs reagent, containing iodine monochloride in acetic acid.
Experimental procedures:
1. Melt the sample, if not already liquid and filter through two pieces of filter paper
to remove any solid impurities and the last trace of moisture.
2. After filtration, allow the sample to achieve a temperature of 68oC – 71oC before
weighing the sample.
3. Once the sample has achieved the temperature, immediately weight the sample
5
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
into a 500 mL flask.
4. According to the iodine value expected for the sample, weigh to the nearest
0.001g in a weighing scoop. The mass of test sample indicated in Table 1.
Table 1: Mass of test sample
Expected iodine value Mass of test sample Volume of solvent
(g/100g) (g) (ml)
< 1.5 15.00 25
1.5 – 2.5 10.00 25
2.5 – 5 3.00 20
5 – 20 1.00 20
20 – 50 0.40 20
50 – 100 0.20 20
100 – 150 0.13 20
150 - 200 0.10 20
5. Add the volume of solvent indicated in Table 1 on top of the sample and swirl to
ensure the sample is completely dissolved.
6. Add 25 mL of Wijs reagent using the pipette into the flask containing the
sample stopper the flask and swirl to ensure an intimate mixture.
7. Prepare a blank with solvent and reagent but omitting the test sample.
8. Immediately store the flasks in the dark room for the 1 hour at a
temperature of 25oC.
9. Remove the flask from the storage and add 20 mL of potassium iodide (KI),
followed and 150 ml of distilled water.
10. Titrate with standard sodium thiosulphate solution, adding it gradually and with
constant and vigorous shaking. Continue the titration until the yellow color due to
iodine has almost disappeared.
11. Add a few drops of starch indicator solution and continue the titration until the
blue color just disappears after very vigorous shaking.
12. Prepare and conduct at least one blank determination with each group of samples
simultaneously and similar in all aspect to the sample.
13. Take and analyze the sample of each 30 min running hours of fractionation plant.
6
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
Table of Data:
Set your recipe based on diagram below:
Figure 1
Table 1: Data of experiment
Segment 1 Segment 2 Segment 3
Starting set point
(SSP1) in oC
Target set point
(TSP1) in oC
Time in minutes
Weight of RBD Palm Oil feed : ____________________ g
Weight of RBD Palm Olein : ____________________ g
Weight of RBD Palm Stearin : ____________________ g
Production Yield : ____________________ %
7
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
Iodine value analysis
Table 2: Result of iodine value for RBD Palm Oil feed
RBD Palm Volume of sodium Volume of sodium Mass of test Iodine value
Oil Feed thiosulphate thiosulphate sample, M (g)
solution used for solution used for the
blank sample, V1 determination, V2
(ml) (ml)
Sample 1
Sample 2
Sample 3
Average
Table 3: Result of iodine value for RBD Palm Olein
RBD Palm Volume of sodium Volume of sodium Mass of test Iodine value
Olein thiosulphate thiosulphate sample, M (g)
solution used for solution used for the
blank sample, V1 determination, V2
(ml) (ml)
Sample 1
Sample 2
Sample 3
Average
Table 4: Result of iodine value for RBD Palm Stearin
RBD Palm Volume of sodium Volume of sodium Mass of test Iodine value
Stearin thiosulphate thiosulphate sample, M (g)
solution used for solution used for the
blank sample, V1 determination, V2
(ml) (ml)
Sample 1
Sample 2
Sample 3
Average
8
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
#Show sample of calculation for each analysis. Find the standard deviation of each data and
present in the table.
5.0 Discussion
1. Explain the principle of crystallization in fractionation process.
2. Sketch your diagram based on Figure 1 and data in Table 1 and explain the overall
process of fractionation.
3. Explain how temperature, agitation and time affect the yield of production for RBD
Palm Olein and RBD Palm Stearin.
4. Compare and explain the result of the iodine value of RBD Palm Oil feed with RBD
Palm Olein and RBD Palm Stearin. Justify your answer.
5. Compare and explain the result of iodine value of RPB Palm Olein and RBD Palm
Stearin with the standard value of refinery quality (refer Appendix 1).
6. Comment on the production yield obtained in this experiment.
7. Discuss any possible errors and state any recommendation to improve the process.
9
Bachelor in Chemical Engineering Technology (Process)
EXPERIMENT No.2
DRY FRACTIONATION of RBD OIL
APPENDIX 1
10
Bachelor in Chemical Engineering Technology (Process) .. ,-,»
\. -' j
