Fuels & Lubricants

Laboratory Manual

T. Kishen Kumar Reddy, Ph.D.(Drexel)

Professor of Mechanical Engg. & RECTOR

Jawaharlal Nehru Tech.University Hyderabad

Hyderabad, Telangana, India

August 2014

MISSION STATEMENT

The primary objective of this laboratory is to determine properties

of several fuels and lubricants, compare them with standards so

as to get an idea about it’s quality. This lab will supplement

theoretical inputs in the basic sciences and engineering courses.

Teams of students will participate in several experiments over the duration of

the Laboratory course. Each member of the team will produce a technical

report of their findings which should include:

a problem statement,

a description of any required calculations (including a

sample calculation),

a copy of the raw data sheet,

a discussion of the experimental results including an

assessment of experimental uncertainty, and

conclusions.

Fuel: A fuel is a solid, liquid or gaseous substance which

on burning or oxidation releases significant amounts of

energy. Generally, it refers to hydrocarbon fuels but there

are other types of inorganic fuels as well such as those used

in rockets, missiles, etc.

Solid – Coal*(Anthracite/Bituminous/Sub-Bituminous/Lignite/Peat),

Wood, Cow dung, Agro-waste, Garbage-urban, etc.

Liquid – Crude oil* and its derivatives* such as:

Gasoline, Aviation Turbine Fuel, Light Diesel Oil,

Kerosene etc.

Gaseous – Natural Gas* and Compressed Natural

Gas*, Liquefied Petroleum Gas*, Biogas, Acetylene

* denotes fossil fuels which are non-renewable

RANK OF COAL

Laboratory testing of fuels can be broadly classified into

seven groups based on the following characteristics:

1. Volatility - Distillation, Vapour pressure, Flash and Fire Point

2. Combustion – Antiknock quality (Octane number), Ignition Quality

Cetane number), Calorific Value, Burning Quality

3. Viscosity and Consistency – Viscosity: Engler, Saybolt,

Redwood & Kinematic; Viscosity Index, Penetration Tests.

4. Melting Point – Freezing point; Cloud point, Pour Point; Drop point

of Grease, Setting Point of Wax, Softening Point of Bitumen.

5. Oxidation - Induction period of Gasoline, Stability Tests of Lube oils,

Residue on Evaporation, Gum Content

6. Corrosion and Protection – Total Sulfur, Doctor Test, Acidity and

Alkalinity; Corrosion protection properties

7. Sundry Tests – Ash, Carbon Residue, Asphaltenes, Dilution Test,

Dielectric Strength, De-emulsification

Need for the measurement of fuel properties:

Flash & Fire Pts. – Important from the point of view of

safety, as low flash petroleum products have potential for

fire hazards in storage and/or handling.

Viscosity – of a liquid is a measure of its resistance to flow.

It plays an important role in the design of fuel pumps.

Calorific Value - is a measure of the heat producing capacity

of a fuel. The designers of Boilers, Furnaces, Engines, etc

need to know the type of fuel to be used and pertinent

properties.

Carbon Residue – It gives an indication of the coke forming

tendency of the fuel. The Board of Revenue utilizes this

property for classification of fuels for excise duty purposes.

It is also used in design calculations of vessels.

Lubricant: is a solid, liquid or gaseous substance

introduced under pressure, in between two rubbing surfaces

under relative motion; thereby lessening the friction and

abrasion, and keeping the surfaces apart. Classified as:

Mineral lubricants: are products obtained from fractional

distillation of crude oil:-

Lubricating oils,

Vaseline's, and

Paraffin waxes

Fixed Oils & Fats: Animal products or vegetable oils. Distinction between oil and fat is a matter of temperature. Below -20°C all

oils become fats and > 50°C, all fats become oils. These are known as

fixed oils because unlike mineral oils, they either decompose by

distillation at comparatively low temps. or oxidize, thus they become

thick, gummy and corroding with little lube value. Many animal fats have

greater lube power than mineral oils of same viscosity, but they

decompose under heat, setting free acids, which attack metals.

Lubricating Oils are characterized by:

Physical properties such as: flash and fire point, viscosity,

oiliness, cold test, volatility and specific gravity.

Chemical properties such as: Acidity, Saponification Value,

Insoluble residue and demulsibility.

Lube oils are used under varied conditions, and a lubricant

is selected according to the requirements. Thus,

knowledge of various properties is essential for selecting a

proper lubricant for a particular machine.

Use of lubricants & Properties Tested:

Automotive Lubricants: Engine Oils, Gear

Oils, Transmission Oils, Specialty Oils (Flash Point, Pour

Point, K. Viscosity, Viscosity Index) and Greases (type of soap,

worked penetration @ 25°C, Drop Point)

Industrial Lubricants: Bearing Oils & Greases;

Compressor Oils (Conradson Carbon Residue), Gear Oils

(Timken OK Load), Heat Treatment Oils, Heat Transfer

Oils, Hydraulic Oils, Cutting Oils, Railroad Oils

(Saponificn. Value, C Residue) , Refrigeration Oils (Floc Point,

Dielectric Strength), Rust Preventive Oils, Rubber

Processing Oils (+ Asphaltenes, Polar Compds., Aromatics,

Saturates), Textile Machinery Oils (Saponificn. Value),

Turbine Oils, Speciality Oils, Industrial Greases (type

of soap, worked penetration @ 25C, Drop Point)

ABEL’S FLASH AND FIRE POINT TESTING (< 50°C)

I. AIM:

To determine the flash and fire points of the given fuel oil using Abel’s flash and fire

point tester.

II. APPARATUS :

Abel’s Flash and Fire point tester, thermometers of suitable range and given oil to

be tested.

III. THEORY :

The fire hazards involved in the storage and handling of fuel oils are indicated by

the flash and fire points. However, there is no correlation between flash and fire

points of an oil and its ignition temperature.

IV. FLASH POINT:

Flash point is minimum temperature at which an oil gives off sufficient vapours to

form inflammable mixture with air that ignite momentarily when exposed to a flame

or an electric spark. Presence of water and volatile organic substances modify the

flash point.

V. FIRE POINT:

Fire point is the minimum temperature at which an oil produces a mixture of its

vapours and air that will burn continuously once ignited, even after the removal of

test flame. The fire point is 25 – 50°C above flash point

The flash and fire points are found under two conditions of

surroundings, that is, open and closed. When the cup is open, flash

point is known as open flash point, when closed by a lid, it is closed

flash point.

In open cup, the oil is heated with the upper surface of the oil

exposed to the room. The vapours rise above the surface of the oil,

and are influenced by the air currents inside the room. The air inside

the room is cool and thereby cools the rising vapours. Thus for open

cup flash point a higher temperature is reached due to cool air than

for the closed flash point; the difference is greater, the higher the

flash point of the oil. A lubricant with a higher flash point is more

safe. An oil with open cup flash point less than 150 C is not used as a

lubricant. The open flash point of all lubricating oils ranges from 150

C – 340 C. The flash points of fixed oils are > than for mineral oils of

similar viscosities (230-330 C for open cup).

Flash Point for Commercial Fuels

Fuel Oil 65 °C Power Kerosene 27 °C

PENSKY MARTEN’S

FLASH & FIRE POINT

APPARATUS (> 50°C)

PENSKY MARTEN'S FLASH AND FIRE POINT TESTING

I. AIM:

To determine the flash and fire points of the given fuel oil using Pensky

Marten's flash and fire point tester.

II. APPARATUS :

Pensky Marten's Flash and Fire point tester, thermometers of suitable

range and given oil to be tested.

III. THEORY :

The fire hazards involved in the storage and handling of fuel oils are

indicated by the flash and fire points. However, there is no correlation

between flash and fire points of an oil and its ignition temperature.

IV. FLASH POINT:

Flash point is minimum temperature at which an oil gives off sufficient

vapours to form inflammable mixture with air.

V. FIRE POINT:

Fire point is the minimum temperature at which an oil produces a mixture

of its vapours and air that will burn continuously once ignited, even after

the removal of test flame.

Viscosity:

When two surfaces are entirely separated by a film

of lubricant the frictional force is entirely due to

viscosity of lubricant. The two surfaces are said to

operate in hydrodynamic or 'fluid film" friction. The

Viscosity of fluid is defined as the shearing force per

unit area required to produce a velocity gradient of

unit volume.

(F/A)

Viscosity = ------------

(dV/dY)

where F = Force required to produce the velocity

gradient; A = Area of liquid film.

V = Fluid velocity at a distance Y from stationary

plate.

The Viscosity of a fluid is an important property

in the analysis of liquid behavior and fluid

motion near solid boundaries.

The viscosity is the fluid resistance to shear or

flow and is a measure of the adhesive/ cohesive

or frictional fluid property.

The resistance is caused by intermolecular

friction exerted when layers of fluids attempts to

slide by another.

The knowledge of viscosity is needed for proper

design of required temperatures for storage,

pumping or injection of fluids

The viscosity measures the resistance to the flow

of a fluid and is inversely proportional to its fluidity.

Greater the viscosity of a fluid, greater is the load

under which it can maintain a continuous film, for

liquids it decreases and for gases it increases with

temperature.

The change per degree C is greater for mineral oils.

The viscosities of oils when measured under great

pressure are greater than the viscosities which are

measured under atmospheric pressure. The

viscosities are usually measured at 40°C and 60°C.

Viscosity and Specific Gravity of some Typical Liquids

centiPoise

(cP)

centiStokes

(cSt)

Saybolt

Second

Universal

(SSU)

Typical liquid Specific Gravity

1 1 31 Water 1.0

3.2 4 40 Milk -

12.6 15.7 80 No. 4 fuel oil 0.82 - 0.95

16.5 20.6 100 Cream -

34.6 43.2 200 Vegetable oil 0.91 - 0.95

88 110 500 SAE 10 oil 0.88 - 0.94

176 220 1000 Tomato Juice -

352 440 2000 SAE 30 oil 0.88 - 0.94

820 650 5000 Glycerine 1.26

1561 1735 8000 SAE 50 oil 0.88 - 0.94

1760 2200 10,000 Honey -

5000 6250 28,000 Mayonnaise -

15,200 19,000 86,000 Sour cream -

17,640 19,600 90,000 SAE 70 oil 0.88 - 0.94

SAYBOLT VISCOMETER I. AIM: To determine the viscosity of a lubricating oil by using a Saybolt

viscometer.

II. APPARATUS : Saybolt viscometer, stop watch and water bath thermometers.

III. THEORY : Viscosity of lubricating oils is measured by an instrument known as

viscometer. Most of the viscometers are of efflux type. In these, a measured

volume of oil at a particular temperature is allowed to efflux through a capillary

tube and the time of flow is noted in seconds. Saybolt viscometer is employed

by the oil industry in U.S.A. The units of dynamic viscosity stokes in MKS units

is centipoise and in the SI system are Mpa-s. Similarly the units of Kinematic

viscosity ν in Mks and SI units are centistoke and mVs respectively.

VISCOSITY: Viscosity is a measure of resistance to relative translational

motion of adjacent layers of a fluid. It is a property of a fluid. The units of

viscosity is poise and centipoise.

Specific Viscosity : Specific Viscosity is the ratio of the viscosity of fluid to the

viscosity of water at 20°C. Since the water has a viscosity of 1 cp at 20°C.

Kinematic Viscosity (v): Kinematic viscosity is defined as the ratio of dynamic

viscosity to the density of the fluid.

An instrument used in the measurement of the

degree Engler, a measure of viscosity; the

kinematic viscosity ν in stokes for this instrument

is obtained from the equation

ν = 0.00147t - 3.74/t,

where t is the efflux time in seconds.

Degree Engler: A measure of viscosity;

the ratio of the time of flow of 200 milliliters

of the liquid through a viscometer devised

by Engler, to the time for the flow of the

same volume of water.

Engler's Viscometer

Aim: To find the viscosity of a given sample of Lubricating oil

Appartus: Engler Viscometer, 200cc of standard flask, Thermometer,

Stop Watch, Spirit Level

Description: The apparatus consists of an oil cup made of brass is

placed centrally in a bath containing water. Inside the oil cup there are

three gauges to the level of its tips in which oil is to be poured. There is

a standard orifice at the center of the base of the cup. The lower end of

the oil cup is provided with a thermometer for recording the temperature

of the oil and to insert a Bakelite valve sticks. The whole bath is centrally

located for the purpose to stop or to allow the flow of the oil through the

orifice. The oil cup is surrounded by a water bath, which is heated by

means of an electric heating element. The bath is provided with stirrer

and a thermometer holding device. The whole apparatus is mounted on

a tripod stand, which can be leveled by the adjustment of leveling feet.

Procedure:

Clean the oil cup & dry it.

Pour the water in the water bath & level the instrument filter

Filter the oil and pour it into oil cup up to the mark.

In a careful and controlled manner heat the water and stir it

continuously until desired temperature is reached.

Stop stirrer and place the clean 200cc flask below the orifice,

Lift the valve stick by means of Hydrometer.

Determine the specific gravity of the oil at different temperatures and

use these densities for further calculations.

Calculate the kinematic and absolute viscosity and tabulate the

results.

Kinematic Viscosity = At - (B/t) centistokes.

Where A&B are Engler Viscometer constants A=0.147, B=374

Time taken for 200cc of oil to flow through the orifice at particular temperature.

Absolute Viscosity = Kinematic Viscosity x Density

Redwood viscometer: A standard British-

type viscometer in which the viscosity

is determined by the time, in seconds,

required for a certain quantity of liquid

to pass out through the orifice under

given conditions; used for determining

viscosities of petroleum oils.

BOMB CALORIMETER (SOLIDS & LIQUIDS)

AND

JUNKER’S CALORIMETER (GASES)

PURPOSE:- Bomb calorimeter is used to determine the

enthalpy of combustion, ΔHcomb, for hydrocarbons.

CxHyOz(s) + (2x+y/2-z)O2(g) -> x CO2 (g)+y H2O(l)

Since combustion reactions are exothermic (gives

off heat); Δ Hcomb is negative.

SIGNIFICANCE:- Measure the heat producing capacity of

the solid /liquid/gaseous fuels

INTRODUCTION:- During oxidization of many materials

energy is released. The materials which produce

significant amount energy are general identified as fuels.

FUELS:- The fuels generally implies hydrocarbon fuels.

The fuels and their major uses are given in the table

FUELS USES

Solid

1.1 Coal(*)

a. Anthracite -steel making

b. Bituminous - electricity generation,

industrial boilers and furnaces

c. Sub- Bituminous -do

d. Lignite - electricity generation

e. peat -do

1.2 woods - cooking, small industries

1.3 cow dung - cooking

1.4 agro-waste - industrial boiling

1.5 garbage-urban - electric power generation

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FUEL USES ------------------------------------------------------------------------------------------------------

2.liquid

2.1 crude oil (*) - electricity generation,

industrial furnace and boilers.

2.2 crude oil derivatives

a. aviation turbine fuel (AFT) - gas turbines used in aviation and

military aircraft, ships, Tanks.

b. light diesel oil - tractors, Boilers and Furnaces.

kerosene - furnace, cooking, boilers

------------------------------------------------------------------------------

GASEOUS USES

3.1 natural gas(*) and CNG)* - electricity Generation,

furnaces,

petrochemical and

fertilizer production,

boilers, cooking,

automobiles and

buses.

3.2 biogas - domestic cooking

3.3 liquefied petroleum gas LPG (*) - domestic and

commercial cooking,

Industrial furnace

3.4 Acetylene welding

A destructive-distillation method

for estimation of carbon residues

in fuels and lubricating oils. Also

known as Conradson carbon

test.

LAB REPORT

WRITING