Objective
- To carry out test
- To provide information to on the status of operation (process losses)
- To provide the information on on the status of product quality
- The data is used to control and monitor the process
- The data can assist engineer or mill manager to modify process or equipment to achieve greater efficiency
Instrument
Digital mass balance
Uv-vis spectrophotometer
Hot plate microwave
Moisture analyser
Thermostatic cabinet
Digital constant temperature tank (SOXHLET extraction apparatus)
Heating block nanocolor vario C2
Distillation apparatus
Air dry oven
Grinding machine
Losses
- Oil loss in EFB
- Oil loss in press fiber
- Oil loss in stork centrifuge
- Oil loss in sterilizer condensate
- Kernel losses in fiber cyclone, ripple mill, LTDS, hydrocyclone
Production oil
Test for moisture
1) Take approximately 10g sample.
2) Put in microwave for 4 minutes to heat it.
3) Weight the sample.
4) Get the difference of the weight after and before dried then divide by the sample weight to get the percentage of moisture of sample
Test for FFA
1) Take approximately 3g sample.
2) Add 50ml isopropanol, 5 drops of phenolphthaen into a flask.
3) Add in few drops of sodium hydroxide into the mixture until it turns purple.
4) Put the mixture on the hot plate and heat until bubbles appear.
5) Remove the mixture from the hot plate and add in sodium hydroxide until the mixture turn into red brown.
6) Record the amount of sodium hydroxide added.
7) Calculate the percentage of FFA by using the formula:
Amount of phenolpthaen added (ml) x normality (2.5600)/weight of the sample (g) = FFA
Crude oil tank, Gutther oil, VC underflow, crude oil tank
To test the oil content, moisture content and sludge content in the samples based on the visible layers.
1) Record the temperature for each of the equipment of which the sample are taken.
2) For VC underflow, the height of the crude oil in the clarifier need to be recorded.
3) Fill each sample in the test tube of 10ml.
4) Put the sample in the centrifuge machine for 10 minutes.
5) The spinning the liquidat high speed will separate the content in the liquid by density. Visible layers will form after the spinning process finished.
6) Remove the sample from the machine and observe the layers formed on the sample
7) The top layer is oil layer, second layeris mixture of sludge, third layer is the water content and the bottom layer is the sludge.
8) Record the volume of each layer and divide by the sample volume to get the percentage of the oil and moisture content.
Figure: centrifuge machine
Figure 4: layer formation
Condensate, Sludge pit, Before stork
The sample from the condensate, sludge pit and before the stork will be taken once a day for daily process control. This sampling method usually takes few hours to 12 hours, so it can only do once a day. And the result usually only can be known on the next day.
Moisture test:
1. Weight 48g of sample in a dish.
2. Heat the sample in the oven for 12 hours at103 degree Celsius.
3. Weight the sample.
4. Compare the weight to the initial weight of the sample, the difference is the moisture content.
Oil content test:
1. Use the dried sample from the moisture test and grind it into powder form.
2. Pure in 150ml of n-hexane and do the SOXHLET extraction for 4 hours.
3. Put the sample in the hour to dried for 2 hours under 103 degree Celsius.
4. Weight the sample and compare the difference in weight.
Storage tank oil and dispatched CPO
The sample of storage tank oil will be taken in the morning everyday. The sample will be tested for the dobi, moisture content, impurities and FFA. The method of testing the moisture and FFA content is the same for sampling method the production oil. For the dispatch CPO, 4 samples will be taken, 2 of them will be given to the driver and another 2 will be used for testing in the lab. Same test with storage tank oil will be carry out on the dispatch CPO.
To test the dobi, uv-vis spectrophotometer will be using.
It measures the intensity of light passing through a sample, and compares it to the intensity of light before it passes through the sample. The ratio is called the transmittance, and is usually expressed as a percentage. The absorbance, is based on the transmittance. The spectrophotometer using in the lab is single beam spectrophotometer.
To test impurities:
1. Put a filter paper in a grooch crucible with a 20-25mm internal diameter base.
2. Rinse it with 10ml of n-hexane.
3. Dry the grooch crucible in the oven for 30 minutes at 103 degree Celsius.
4. Cool down the grooch crucible in the desiccator.
5. Weight and record the grooch crucible with the filter paper.
6. Add in 20g of oil sample into a conical flask.
7. Add in 100ml of n-hexane.
8. Carefully filter the sample by vacuum.
9. Rinse the conical flask with n-hexane to ensure all of the sample are flow into grooch crucible.
10. Rinse the crucible with n-hexane and wipe it with a tissue paper.
11. Dry the crucible in the oven for 30-60 minutes at 103 degree Celsius.
12. Measure the weight of grooch crucible and we can get the weight of the impurities.
Control parameter:
FFA < 7%
DOBI > 2.7%
Moisture <0.2%
Impurities < 0.05%
Press cake fibre & EFB press
The fibres from the screw press machine will be collected as the sample to test the oil losses, moisture content and nut breakage in the fibre while the sample from EFB press will tested on moisture and oil content only. The sample will be collected every 2 hours until the mill process finished.
If the oil content in the fibre is high, the oil losses will be high. So the adjustment need to make on the pressing machine ampere reading to get higher press force. In same way, if nut breakage is higher than control limit, the ampere control of the machine need to be reduced. Proper adjustment need to be made to achieve the balance of both oil and nut optimum extraction.
Control parameter for press cake fibre:
Nut breakage: < 10%
Oil content: < 7.3%
Control parameter for EFB press fibre:
Oil content < 3%
Hard bunch and USB
100 sample will be taken at both of the thresher every 2 hours. The number of hard bunch will be calculated from the 100 sample. This sampling result is important to determine the performance of the sterilisers. Pressure, temperature and holding time are the factor that affect the bunches. If the hard bunch and USB is more than the control limit, the pressure and holding time need to be increase for the sterilizing condition.
Control parameter:
1st thresher < 5%
2nd thresher < 3%
Nut and kernel station
Overall whole kernel: > 40%
Production quality: moisture (6-6.5%), dirt & shell(5-6%), FFA (<3%)
Despatch quality: moisture (<7%), dirt & shell(<6%), FFA (<5%)
Place for sample:
Fibre cyclone
- To determine the kernel loss through depericaper, if the losses is too high, the winds speed need to be adjusted by the opening damper. The amount of whole kernel, broken kernel, split nut, nut will be counted by weight.
Control parameter:
Total kernel < 1%
Ripple mill
-To determine cracking efficiency. The amount of whole kernel, broken kernel, split nut, nut will be counted by weight.
Control parameter:
Cracking efficiency > 98%
LTDS
-To determine the kernel loss through LTDS. The amount of kernel will be calculated by weight.
Control parameter:
1st stage: kernel < 2%
2nd stage: kernel < 1%
Hydrocyclone
-Kernel and shell sample will taken from the hydrocyclone.
Kernel: percentage of dirt to the sample will be calculated. The dirts are the nuts, split nuts, stone, free shell and broken kernels.
Control parameter:
dirt < 5%
Shell:
Percentage of kernel contained in the sample will be calculated. The amount of whole kernel, broken kernel, split nut, nut will be counted by weight.
Control parameter: kernel < 2%
Wet kernel (before entering kernel silo)
The kernel sample will be collected from the top of the kernel silo. This is to test the moisture and dirt of the kernel before enter silo for drying. The dirts are, nuts, split nuts amd free shells.
Control parameter: dirt < 5%
Kernel silo
To determine the moisture and dirt of the kernels. Sample of dried kernel will be taken before sending to kernel bunker. The dirts are, nuts, split nuts amd free shells.
Control parameter:
Moisture < 7%
Dirt < 5%
Dispatched kernel
Dispatched kernel will be tested on FFA, moisture content and dirt content.
Control parameter:
Moisture < 7%
Dirt < 6%
FFA < 5%
Kernel test:
There are few test on kernel including moisture content, shell and dirt content, broken kernel and split nut and FFA.
For shell and dirt, kernel and split nut, the test will be carry out by separating the nut, split nut, whole kernel, broken kernel, shell depend on the testing criteria. Then the amount of every separated contents will be weighted.
Calculation: To calculate the amount of kernel, the weight of whole nut will be divided by 2 and the weight of split nut is divided by 3 and times 2. By this method, we are assuming the weight of the kernel is 1/2 of the nut weight and 2/3 of the split nut weight. The other method which is more accurate is by mashing the nut to remove the shell and weight the kernel. This method is not practising in the lab because it is time consuming.
For moisture test, the sample of the kernel will be grind into smaller pieces with diameter less than 2mm. Then add in approximately 10g of grind kernel sample and heat in the oven for 4 hours. Then the weight different after heated and the initial weight of the sample is the moisture content. Divide it by the total sample weight to get the percentage of the moisture. The moisture content needed to be control under 7%. High moisture content will lead to increase in FFA and cause to kernel to be rotten quickly.
For FFA test, put the grind kernel to a filter paper that folded into a cone shape and put on a beaker. Add in n-hexane to extract the oil from the kernel. After that the steps to test the FFA in the oil extracted is the same as testing FFA in production. FFA is free fatty acid. The amount of FFA need to be as low as possible to ensure the good quality of the kernel.
Boiler test
1. Boiler water
-Total hardness test
-Hydrate alkalinity
-Sulphite
-Phosphate
-Chloride
-Silica
-Total dissolved solids
2. Softener
-Total alkalinity
-Chloride
3. Feed water
-Total hardness
-Total iron test kit
-Chloride
-Total dissolve solids
Effluent test
There are total of 5 stages in effluent pond, holding pond, cooling pond, acidification pond, anaerobic pond, irrigation pond. Each effluent sample will be test on 3 tests, COD, BOD and pH.
COD test
1) Insert 0.2ml of the sample into a test tube slowly to prevent the mixing of 2 layer.
2) Close the test tube and shake it.
3) Put the test tube in the heating block for 2 hours under 148 degree Celsius
4) Shake the tube after 10 minute removed from the heating block.
5) Put the test tube into cell compartment and press M.
BOD test
Initial preparation:
A) Aerated dilution water preparation
1. Fill a 10 litre bottle to 3/4 full.
2. Induce air flow into the bottle for 6 hours using an air pump.
B) BOD nutrient mixture preparation
1) Prepare 2 bottle of BOD3 nutrient mixture powder and label with R1 and R2.
2) Pour 10ml of Aerated dilution water into the BOD3 mixture.
C) Preparation for control and sample.
- control:
1) Pour 500ml of aerated dilution water into a bottle.
2) Pour in 1.25ml nutrient mixture R1 and R@ into the bottle.
3) Shake the bottle to homogenized the mixture.
- sample:
1) Pour in the nutrient mixture and aerated dilution water according to table 1.
D) Preparation for BOD3 testing end reading.
1) Prepare 2 bottle and label it as C2 and S2.
2) Fill in the C2 bottle with the “control” bottle until full and S2 bottle with the “sample” bottle. Keep both of the bottles in the incubator BOD for 3 days.
E) Preparation for BOD3 testing initial reading
-Blank:
Take 1 test tube and pour in the the mixture from the “control” bottle and label as C1.
-Sample:
Take 1 test tube and pour in the the mixture from the “sample” bottle and label as S1.
* Prevent the formation of air column in the test tube, fill the test tube until the mixture spill out.
F) Determination of BOD3 value.
1. Insert 2 drops of BOD3 R1 and R2 to C1 and S1.
2. Shake each test tube to make sure they mixed well.
3. Close the test tube for 2 minutes Figure 9: Device to insert the effluent into test tube
4. Fill in 5 drops of BOD3 R3 mixture. Prevent the formation of air column
5. Set the method on the photometer PF-12 with 822.
6. Pour in C1 into the photometer PF-12 and press M button.
7. Record the reading of C1.
8. Repeat step 7 & 8 to determine the S1 reading.
BOD calculation:
C0 = C1 - C2
S0 = S1 - S2
BOD3 = D x (S0-C0) + C0
* refer the table 1 for the value of D. Figure 10: Insert the sample to the test tube
Table 1
Discussion
Laboratory result is very important to monitor the performances of the process of the mill. Operator and assistance manager use test result from laboratory to control the process to achieve maximum OER and KER. Hence, the laboratory test must be precise and accurate all the time.
There are several common error happen during the lab test such as parallax error, zero error, handling method. Human emotional also can affect the handling of the sample and affect the test result. This is unavoidable, but monitoring of the lab test by the management should be done once a while to ensure the operator in the lab is caring out the test properly.
