Properties of Lube oils

1. Lube Oils

2. • Heavy fractions of crude
• They have a boiling point above 350°C.
• Mainly obtained from VDU
• Composed of paraffins, napthenes, aromatics and unsaturated hydrocarbons.
• Mainly made up of napthene rings and aromatic rings.

3. Classification Of Lube Oils
• Depending upon the service intended for lube oils are classified in following types.
1. Machine and engine oils
2. Compounded oils
3. Turbine oils
4. Cold test oils
5. Transformer oils
6. Color oils
7. Corrosive oils

4. 1. Machine and Engine oils
• High viscosity index oils because they have to serve under varying temperature
conditions.
• These oils arte further subdivided into straight, premium and heavy duty oils depending
upon their viscosity index and serviceable temperature.
• Uses of Oils in different services:
1. HVI - Aircrafts, high speed operation
2. MVI – petrol, diesel and stationary vehicles
3. LVI – light equipments

5. 2. Compounded oils
• Exhibit more wettability characteristics which makes them more suitable for steam engines,
compressors and quenching and tempering operations.
• Emulsibility is considered to be more important than viscosity index.
3. Turbine oils
• High speed machinery such as steam turbine, electric motors should have emulsion-free oils
• Extreme stability is required for such oils.

6. 4. Cold test oils
• Suitable for refrigeration and hydraulic system.
• Pour point is the most important property for these types of oils.
5. Color oils
• Used in textile, food and paper industries.
• Depending upon the application, the concentration of sulfur aromatics and resin bodies are
fixed.
6. Corrosive oils
• Used in cutting, shaping of mates.
• Heavy duty oils are extreme pressure lubes are of this type oils.

7. Tests For The Lube Oils
• These are some of the important tests for lube oils:
1. Flash Point
2. Pour point
3. Viscosity and viscosity index
4. Oxidation stability
5. Carbon residue

8. Carbon Residue
• It shows the cracking tendency of the oil
• Heavy oils have a tendency to crack at higher temperature with carbon deposition
• The amount of carbon formed during cracking provides an idea of usability of oil at high
temperature.
• Two methods are used for this test:
1. Conradson method
2. Ramsbottom method

9. Conradson Method
• 10 gms of sample is heated in silica-crucible. The decomposing is achieved by high heating
rates.
• The fumes appeared at the chimney top are burned. The heating rate is adjusted such that the
burning sustains, but the flame is never allowed to cross the bridge of the chimney. After the
burning of the fumes further heating is continued.
• Then the set is cooled and the silica crucible is weighed to get the weight of carbon deposit.
Expressed is percentage gives conradson carbon residue.
• Prescribed heating rates:
• Pre-ignition period: 10±1.5 min.
• Burning of fumes: 13±1 min.
• String burning: 7 min.
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• Total time: 30±2 min.

10. Ramsbottom Method
• Sample is fed into a glass bulb which has a capillary end.
• The bulb is kept into a heat bath at 550ºC and it is allowed to decompose for 20 minutes.
• After heating the bulb is cooled and weighed to fine the carbon formed.
• Best quality of oils gives less carbon residue.
• Conradson carbon residue should not exceed 0.2 to 1.0%.

11. Oxidation Stability
• This test revels the deterioration characteristics of oil on oxidation.
• Higher parrafins are easily oxidized compared to napthenes and aromatics.
• For this test , air is passed at a rate of 15 liters per hours through 40 ml of sample kept at
200ºC for 6 hours. At he same condition second oxidation period is carries out foe 6
hours.
• Then the sample is cooled and its viscosity and carbon residue are found out and
compered with the original value.

12. Transformer Oils
• They are used in electrical industry mainly for insulating, cooling purpose. These oils protect the
equipment from moisture.
• Transform oils are classified in two categories:
• One which are used in transformers and circuit breakers etc. these type of oils are low viscous,
thermally stable but having high boiling point.
• Other type of oils are used for impregnating cables and papers used in electrical industry. These type of
oils are highly viscous and act as insulator only.
• Some important test for transformer oils are:
• Acid value
• Flash point
• Dielectric strength
• Pour point
• Sludge value
• Copper corrosion test

13. Dielectric Strength
• High dielectric strength is required for insulation purpose.
• Electric strength or break down test is performed by in creasing the voltage at a rate of 2kV/s
in between electrodes of 12.5 to 13 mm dia. which are placed at a distance of 2.5±0.1 mm.
The cell capacity is usually between 300-500 ml.
• Voltage is continuously raised until the break down is achieved. A satisfactory oil test should
show a break down strength of around 120 kV/cm.
Sludge Value
• Sludge value is found out by precipitating insoluble with heptane.
• This test is performed before oxidation and after oxidation of oil. High sludge formation
indicates the negative quality of oil, which also indicates the high percentage of oxidative
product.

14. Copper Corrosion Test
• The use of copper in electrical industry is immense, hence the attitude of oil towards
copper should not be calamitous.
• Test is carried out by heating a copper strip into oil for 3 hours at 100ºC and then the
copper strip is observed.
• Discoloration of copper strip is a direct indication of corrosiveness of the oil as given
below:
• Light orange, looks like a fresh one
• Dark orange to red or multi colored
• Multi colored with greenish tinge
• Dark grey to black color

15. Bitumen
• Residual product obtained from CDU. Solid at room temperature and has very high
viscosity.
• Bitumen obtained from CDU is of poor qualities. To increase its usability and grades air
blowing is carries out.
• Uses:
• In highway construction
• Waterproofing and coating works
• Tests:
• Softening point
• Penetration index

16. Softening Point
• Softening point is found out by Ball & Ring test. Bitumen is first melted and casted into discs of
two numbers in standard rings.
• A steel ball weighing 3.5±0.5 gm is kept on each casted disc of bitumen.
• The whole arrangement is immersed in a water or glycol bath. As the heating proceeds
softening occurs.
• The temperature at which the sample ditches from the die and falls, indicates its softening
point. Higher the softening point, better is consistency of bitumen.
Penetration Index
• Hardness of bitumen is determined by this test. A standard needle is allowed to penetrate
under a load of 100 gm through a sample kept at 25ºC for 5 sec.
• Distance travelled by needle indicates the consistency of sample.
• Distance travelled depends upon its load and softening point.

17. Ductility
• For surface application bitumen must posses high ductility. It is measured by dectilometer.
• Ductility is a measure of the capacity of bitumen to stretch or elongate.
• This test Is carried out by pulling a test piece of bitumen of standard dimension at a
uniform rate of 5cm/s at 25ºC.
• Higher the elongation, higher will be the ductility of bitumen.

18. WAXES

19. Types Of Waxes
• The commercial petroleum waxes can be broadly classified as paraffin wax,
microcrystalline wax and petrolatum.
• The paraffin waxes are produced from waxy distillate of paraffin-base or mixed base crude
of high pour points.
• The microcrystalline waxes are produced from the distillation residue from the above
crudes, waxy sludge deposited in their storage

20. Paraffin wax
Grade I
an extra refined paraffin wax.
Melting point grades produced
are 135/140ºF, 140/145ºF,
145/150ºF.
Mostly used for foodstuff
packaging industry and some
cosmetic perception.
Grade II
It is a refines paraffin wax,
containing a maximum of 0.5% of
oil by weight. Major grades
produced are 135/140ºF,
140/145ºF, 145/150ºF.
used for candle manufacturing,
coating of paper for general
packaging, polishes and hard
board, water proofing
formulations processing rubber
goods etc.
Grade III
It is a semi refined paraffin wax,
containing a maximum of 3.5% of
oil by weight. Only one grade is
produced -128/132ºF.
used for impregnation of match
sticks, textile and pencil
industries, water proofing
formulations etc.

21. Microcrystalline Wax
• These contain a considerable quantity of branched chain hydrocarbons. The commonly
used microcrystalline waxes in India are graded as follows:
• Grade I: It is a refined microcrystalline wax of flexible type with a melting point of
165ºF. The oil content is about 4%. This is mostly used in lamination, sealing
compounds, petroleum jellies rust preventives and cosmetics.
• Grade II: It is also a flexible type of wax, but it defers from Grade I in that it is an extra
refines wax. Its application is similar to Grade I.