FIMA BIODIESEL SDN
BHD (FBio)
Analysis tests in biodiesel production
By:
Quality Control Department
PROCESS FLOW CHART
Lipids Structure, Properties and Function
■ Lipids are biological molecules that are insoluble in water,
but are soluble in non-polar solvents, meaning that they are
non-polar molecules.
■ It comprises a group of naturally occurring molecules that
include fats, waxes, sterols, fat-soluble vitamins, such as
vitamins A, D, E, and K, monoglycerides, diglycerides,
triglycerides, phospholipids, and others.
■ Some lipids such as steroid hormones serve as chemical
messengers between cells, tissues, and organs.
INTRODUCTION
■ There are a few sources of oil to produce biodiesel from
vegetable oil such as palm oil, sunflower oil, soybean oil and
also used-cooking oil etc.
■ We use RBDPO which comes from palm oil.
■ We use catalyst, sodium methylate, in our biodiesel production
which is a corrosive substance.
■ Biodiesel is the “green” equivalent for petroleum diesel
(petrodiesel).
■ Biodiesel is a renewable fuel derived from vegetable oils,
animal fats or cooking oils.
■ Malaysia use 10% of biodiesel to be blended with diesel fuel
which is called B10.
INTRODUCTION of biodiesel
■
1.
2.
3.
4.
Important environmental benefit of biodiesel :
biological degradable,
less poisonous
Do not contain aromatics
very low sulfur content
■ Problem with biodiesel :
1. Biodiesel is more expensive than regular diesel fuel
2. Biodiesel is not very suited for use in low temperatures (cold weather)
■ Quality requirements of biodiesel for use as pure biofuel or blending stock
for diesel fuel are defined in ASTM D6751 and EN 14214 specification.
■ Standards ensure that the following important factors in the biofuel
production process are satisfied : complete reaction, removal of excess
water and glycerin, absence of Poly Unsaturated Fatty Acids, removal of
alcohol and absence of free fatty acids.
1. QUALITY TEST: WATER CONTENT
■ Recommended Limit: Below 500 ppm (mg/kg) (or 0.05 %
by Volume)
■ Reasons for Test:
1. This test monitor water percentage in the oil.
2. If extremely wet component is used to make Biodiesel, the
water will mix with the catalyst (Sodium or Potassium
Hydroxide) and begin forming soap out of the oil.
3. When soap is formed, it robs the catalyst from being able
to fully react with oil and become Biodiesel, resulting in
poorly converted bio-fuel.
4. Excess soaps in Biodiesel can lead to unwanted
emulsions during the washing process.
KF titrator/ moisture analyser
2. QUALITY TEST: ACID VALUE (titration)
■ Recommended Limit: < 0.50 (unit = mg KOH/g)
■ Reasons for Test:
1. To measure rancidity of sample as FFA is formed
during decomposition of oil glycerides.
2. Rancidity = complete/incomplete,
oxidation/hydrolysis of fats and oils when exposed
to air, light, or moisture or by bacterial action,
resulting in an unpleasant taste and odor.
3. QUALITY TEST: IODINE VALUE
(GC/titration)
■ Recommended Limit: < 120 g iodine/100g
■ Reasons for Test:
1. to determine the amount of unsaturation contained in fatty acids. This
unsaturation is in the form of double bonds which react
with iodine compounds.
2. The higher the iodine value, the more unsaturated (meaning has at
least one double bond within the fatty acid chain) fatty acid bonds are
present in a fat.
3. Can use to differentiate btwn all types of edible oil (to categorize oil into
diff. class)
WIJS method for IV test
■ Wijs method involves the addition of a solution of iodine
monochloride in a mixture of acetic acid and cyclohexane to a test
sample.
■ After iodine addition to the double bonds has occurred, the excess
iodine monochloride is reduced to free iodine by addition of
potassium iodide solution and water.
■ The liberated iodine is titrated with a standardized solution of sodium
thiosulphate with starch as indicator.
■ Results are expressed as the number of grams of iodine absorbed by
100 g of the oil sample.
■ Precautions to be taken when carrying out Wijs analysis are to restandardize sodium thiosulphate solutions with potassium
dichromate solution at regular intervals and to carry out blank tests
on the Wijs reagent. This is due to the long term instability of both
solutions.
Iodine value of edible oils
4. QUALITY TEST: METHANOL PURITY
■ Recommended Limit: 99.5% Pure by conventional method or < 0.2%
(m/m) by GC analysis
■ Reasons For Test:
1. if methanol expose for long periods of time, it can absorb moisture from
the air.
2. Impurity in Methanol is water.
3. In case of oil, present of water in the process can potentially lead to soap
production and poorly reacted Biodiesel.
5. QUALITY TEST: 3/27 BIODIESEL
CONVERSION TEST (TLC)
■ Recommended Limit : none, just for estimation
(visual reference)
■ Reasons for Test:
1. This test is used to identify and estimate
reaction process of Biodiesel.
2. If the fuel isn't well reacted, then it may need to
be processed again.
3. Also, poorly reacted Biodiesel can be the cause
of emulsions (mixture of oil, glycerine & water)
when water washing the Biodiesel.
5. QUALITY TEST: GAS CHROMATOGRAPHY (MG,
DG, TG, FREE GLYRINE, TOTAL GLYCERINE &
ESTER CONTENT)
■ Recommended limit:
■ monoglyceride = < 0.7 % m/m ; diglyceride = < 0.2 % m/m ; triglyceride = < 0.2 % m/m
■ Free glycerine = < 0.02 % m/m ; total glycerine = < 0.25 % m/m ; Ester = > 96.5 % m/m
■ Reason For Test:
1.
This test is used to identify complete conversion of trans-esterification (FFA + MeOH =
FAME/Biodiesel)
2.
Incomplete trans-esterification will produce fuel that has poor flow qualities and absorb
water, making it burn poorly or cause pre-ignition condition (knocking).
3.
If incomplete occur, will cost more money, to buy catalyst (it is the most expensive
material)
ESTER = mixture of carboxylic acid and alcohol
ESTER CONTENT (GC method)
■ Ester content is used to determine the oil conversion
into biodiesel (i.e., is related to the final biodiesel purity).
■ Recommended limit : > 96.5% (m/m)
■ Total glycerol content is one of the most important properties among
the various properties of biodiesel. It has a close relationship with
ester content because both are related to the remaining amount of
intermediate compounds (mono- and di-glycerides) as well as the
unconverted triglycerides.
■ The total glycerol content increases, then the ester content in
biodiesel decreases.
Principle of gas chromatography:
■ The sample solution injected into the instrument enters a gas stream
which transports the sample into a separation tube known as the
"column." (Helium or nitrogen is used as the so-called carrier gas) .
■ The various components are separated inside the column.
HOW TO HANDLE THE SAMPLE
■ The correct sampling method to be used for sampling
any vessel is to drain the sample at least 3 times.
■ Next, we must use a suitable container so that the
sample wont be contaminated.
■ We must also handle the sample during sampling time
with care and closed the container lid tightly.
■ Before sampling, we must use suitable personal
protective equipments (PPE) such as safety helmet,
safety glove, safety boots and etc.
6. QUALITY TEST: SAPONIFICATION
VALUE (soap content)
■ Main problem face when handling biodiesel production which is soap formation.
■ Reasons for Test:
1. When Biodiesel is produced, a certain amount of soap gets produced.
2. When the Biodiesel is properly washed, soap levels should be greatly reduced.
3. If soap levels are still high, the Biodiesel can be rewashed.
What is soap? Consist of sodium or potassium salts of carboxylic acid.
Saponification is a chemical reaction that involves the production of a metal salt or
soap. The reaction involves the attack on a methyl ester, free fatty acid, triglyceride,
or other glyceride by a hydroxide ion, –OH.
The hydroxide ion implies the presence of water in the system. There is always some
water present, and there will always be some soap formed when biodiesel is made.
Formation of sodium methylate
Formation of soap
7. Oxidation stability (oxi. Stab.)
■ Recommended limit : min 8 hours (standard method: EN
15751)
■ Reasons for test :
1. Oxidation Stability is one of the most important properties of
fatty acid alkyl esters (biodiesel fuel) and primarily affects the
stability of biodiesel during extended storage.
2. Degradation by oxidation yields products that may
compromise fuel properties, impair fuel quality and engine
performance.
Biodiesel rancimat for Oxi. Stab. analysis