Energy engineering-lab-manual zaman-1 a

Department of Chemical Engineering, Energy Engineering (Lab Manual)
Wah Engineering College, University of Wah, Wah Cantt
For queries on this page write at zaman.sajid@wecuw.edu.pk Page| 1

Table of Contents
COAL ANALYSIS ............................................................................................................................ 2
Theory ............................................................................................................................................ 2
Experimental Work ........................................................................................................................ 9
LUBRICATING OIL ANALYSIS ............................................................................................... 13
Theory ......................................................................................................................................... 13
Engler Viscometer ....................................................................................................................... 25
Theory ...................................................................................................................................... 25
Experimental Work .................................................................................................................. 28
Brookfield Viscometer ................................................................................................................. 34
Theory ...................................................................................................................................... 34
Experimental Work .................................................................................................................. 44
DIESEL ANALYSIS (ANILINE POINT AND DIESEL INDEX)................................................. 50
Theory .......................................................................................................................................... 50
Experimental Work ...................................................................................................................... 55
SPECIFIC GRAVITY MEASUREMENTS .................................................................................... 57
Theory .......................................................................................................................................... 57
PETROL ANALYSIS (FLASH POINT) ........................................................................................ 66
Theory .......................................................................................................................................... 66
CLOUD POINT AND POUR POINT ............................................................................................. 71
Theory .......................................................................................................................................... 71


COALANALYSIS
Theory
INTRODUCTION
Coal was known to man thousands of years ago, ancient writing tell us that three thousand
years ago the Chinese knew that certain kinds of black rock would burn, and in one part of
the country where there was little wood they used to dig into the earth to find this black
rock for their fires purposes. This is the first evidence of coal being deliberately dug from
the ground, but it is quite possible that even before this, coal was used for fuel in some
parts of the world. Early man probably discovered it by accident, when he noticed that in
some places the stones on which he built his fires would burn.
TYPES OF COAL
Coal is formed by the vegetable matter, which gets converted into coal via different stages
of the maturity of coal namely peat, lignite, bituminous and anthracite. Here peat is the
most immature coal hence it is of the lowest rank whereas anthracite is the most matured
coal hence of the highest rank.
PEAT
Peat is included under this very first heading because it is the first stage in the formation of
coal (though if it is not deeply buried, it will never become coal) from wood under the
action of temperature, pressure and bacteria. Peat is brown in color and highly fibrous in
nature. With increase in depth, the color becomes darker and finally black, when vegetable
structure is not so obvious. The type of the peat usually dug for fuel consists of the partly
decayed reeds and mosses growing in bogs. Peat bogs, often called ‘mosses’, are found in
Ireland, Scotland and Somerset, as well as in many parts of the world.
LIGNITE
It is the second stage product in the formation of coal from wood. Brown coal results from
the first stage of alteration of the buried peat. It is brown and crumbly and can often be
seen to be composed of decayed woody material.
BITUMINOUS COAL


The commonest type of coal used in houses and factories, is known as bituminous coal. It
is always black and is made up of bands or layers which vary from bright and glassy to
dull and sooty. This type of coal generally breaks easily into rectangular block along
planes of easy splitting (cleavage) which the miner calls ‘cleat’ of the coal.
ANTHRACITE
Anthracite is a form of coal showing the greatest amount of change or alteration from the
peaty layer of which it was originally formed. It is hard and shows little sign of bending,
but has a luster (or shines) rather like dull steel, and it breaks into skew-shaped blocks.
CHEMICAL COMPOSITION OF COAL
Coal contains a variety of chemical constituents, not all of which are combustible. Coal is
subdivided into two classes:
• Combustibles
• Non- combustible
SOLID FUEL
Combustible Non combustible (inert)
Volatile non volatile Moisture Inorganic Ash
-Hydrocarbon - Carbonaceous
- Polymeric


COMPARISION OF DIFFERENT TYPE OF COALS
Peat Lignite Bituminous Anthracite
Carbon contents
(%)
23 42 75 – 90 91 – 93
Moisture
contents (%)
53 35 <10 1 – 2
Volatile Matter
(%)
26 28 20 – 40 2- 9
Ash (%) 6 6 8.35 7
Calorific Value
(Kcal/Kg)
4600 6000 7900 7700
What do you infer from above table?
ANALYSIS OF COAL:
The primary methods for the analysis of coals are;
• Proximate Analysis
• Ultimate Analysis
PROXIMATE ANALYSIS:
The proximate analysis comprises determinations of
• moisture,
• volatile matter,
• ash
• Fixed carbon (by difference)
The analysis provides data for a first general assessment of the coal’s quality and type.
The results, except moisture, are usually expressed on the basis of percentage by weight of
dry coal.
1. Moisture:


Moisture, particularly a high percentage, is naturally undesirable to the purchaser of a coal
because he is paying for a non-combustible material and because a portion of the heat of
combustion of the coal is consumed in its evaporation.
Effects of moisture on coal:
• Reduce the Calorific Value (CV)
• Increase the consumption of coal
• Lengthens the time of heating
• The customer pays for coal weight not for coal having high moisture.
• The transportation of coal carries extra eight of moisture present in it and so pays
extra transport cost.
2. Volatile Matter (VM):
The volatile matter represents the portion of a coal which is converted into volatile
products when the coal is heated in the absence of air. Certain gases like CO, CO2, CH4,
H2, N2, O2, hydrocarbons etc are present in coal which comes out during its heating.
Because the proportion thus vaporized varies with temperature and time of heating, for
comparative results the conditions of the test are standardized and are rigidly adhered to.
Effect of VM on Coal:
• Ignites easily I.e. it has lower ignition temperature
• Burns with long yellow smoky flame
• Has lower calorific value
• Gives more quantity of coke oven gas during carbonization
• Requires larger volume for combustion
• Has higher tendency to catch fire when stored in open space
3. ASH
Coal ash is derived from clay, iron pyrites, limestone, sand and other mineral matter, all in
a more or less finely divided form distributed throughout the coal in the seam, clay, shale
or slate from the floor, the roof of the seam, or veins in the coal mass; and the inherent
inorganic matter chemically combined with the organic matter of the coal.
Effects of Ash on coal:


• A coal with high ash content:
• Is harder and stronger
• Has lower CV
• Produces more slag (impurities) in the blast furnace when coke made out of it is
used therein.
Do you know what the relationship of mineral matter and ash is? Hint: it’s something
mathematically related.
4. FIXED CARBON:
It is the pure carbon present in the coal. Higher the fixed carbon content of the coal, higher
will be its CV. The fixed carbon is obtained by subtracting from 100 the sum of the
percentages of volatile matter and ash in the dry coal.
Fixed Carbon = 100 – (moisture +volatile matter less moisture +ash)
ULTIMATE ANALYSIS:
Ultimate analysis means finding out the weight percent of carbon, hydrogen, nitrogen,
oxygen and sulfur of the pure coal free from moisture and inorganic constituents. This
analysis gives the elementary constituents of coal and is useful to designer of coal burning
equipment and auxiliaries.
Normally, the analysis provides the following data:
• Elemental carbon(C)
• Elemental hydrogen(H)
• Elemental sulfur(S)- both organic and inorganic
• Elemental nitrogen (N) – nominally about 1% by weight
• Ash
• Heating value
Coal is a highly variable substance, it is important to have proximate and ultimate analysis
data.
Why do you think these analyses are important to be performed before the use of coal?


BASIS FOR REPORTING THE ANALYSIS OF COAL
It is reported on the basis of
• Run of mine coal
• As received (received after size reduction)
• Air –dried
• Dry-coal
• d-a-f(dry ash free)
• d-m-m-f ( Dry mineral matter free)
• Mineral matter free
AIR DRIED COAL
Freshly mined coals gets air and sun –dried during its storage, hence its moisture content,
varies depending on the humidity and the temperature of the moisture air.
WHAT IS DRY COAL?
When the effect of moisture on the analytical data is to be completed eliminate then the
coal analysis is reported on dry –basis.
WHAT IS DRY ASH FREE BASIS
In this effect of ash and moisture in coal is eliminated by reporting data on d.a.f basis. This
data is suitable for comparing the pure coal with low ash coal < 10%.
What IS D-M-M-F BASIS?
For high ash coal (>10%) the mineral matter of the coal is around 10% more than its
ash.For low ash coals mineral matters can be considered to be equal to this ash content.
Hence, for high ash coal, the comparison of pure coal can be done if its analysis is
reported d-m-mf basis instead of d-a-f.


WHAT IS MINERAL MATTER FREE BASIS (m-m-f)?
In this, the effect of mineral matter is eliminated. It includes the moisture.
WHAT IS RANK OF COAL?
It denotes the maturity of coal. It increases from peat, lignite, bituminous, anthracite.
CALORIFIC VALUE
The quantity of heat (Kcal) liberated by the combustion of unit quantity of fuel is called its
calorific value.
Units: Kcal/kg for solids and liquid fuels and Kcal/Nm3 for gaseous fuels. Nm3 means
volume of gas in m3 at Normal Temperature and Pressure (NTP) which is 0o
C and 760
mmHg. Since the volume of gases varies sensitively with pressure (Boyle’s Law) and
temperature (Charles’ Law) hence their volume is expressed at NTP in Nm3 to have a
standard measurement.
Gross Calorific Value (GCV)/Higher Heating Value
GCV is the quantity of heat librated by combusting the fuel in oxygen saturated with water
vapor, the original material and final products of combustion being at a reference
temperature (25o
C) and the water obtained from the fuel being in the liquid state.
Net Calorific Value (NCV)/Lower Heating Value
NCV is the quantity of heat librated by combusting the fuel in oxygen saturated with water
vapor, the original material and final products of combustion being at a reference
temperature (25o
C) and the water obtained from the fuel being in the vapor state.
GCV = NCV + m λ
FACTORS WHICH DECREASES THE CV
Higher moisture content
Higher VM
Higher Ash


Higher N2
Lower Fixed Carbon
Lower H2
Experimental Work
OBJECTIVE
To Perform the “Proximate anaylsis” of given sample of air dried coal
a) To determine the percentage of Moisture content.
b) To determine the percentage of volatile Matter.
c) To determine the percentage of Ash.
d) To determine the percentage of Fixed Carbon.
APPARATUS
Muffle furnace, crucible and Petri dish, Oven, stop watch,Balance, Desicator and given
sample of Coal.
MOISTURE CONTENT
PROCEDURE
Take a Petri dish and tare it in oven at about 105 ∼ 110C°.
• Take 1gm of powdered air dried sample of coal (of 72 mesh British standard i.e-72 B.S)
in petri dish and weigh it.
• Place the sample in oven and heat it for about it 105 ∼ 110C°for one hour.
• Remove the dish from oven, cool it in the desiccator and weigh as soon as cool.
• Calculate the loss in weight.
• Calculate the percentage moisture in the coal sample.
OBSERVATION AND CALCULATION
Weight of sample (air dried coal) = Z1 = g.
Weight of sample after heating = Z2 = _________ g


Loss in weight Z3 = (Z1-Z2) = _________g.
%age moisture M1 =(Z3/Z1) × 100 = __________ %
VOLATILE MATER
PROCEDURE
• Take a translucent silica crucible and tare it, till constant weight is obtained.
• Take 1g. of air dried coal (-72 B.S) In crucible whose moisture content has already
been determined.
• Heat the sample for exactly 7 minutes in the muffle furnace at a steady temperature of
900∼ 950 C°.
• Remove the crucible from muffle furnace and cool it in the desicattor as weigh as soon
as cool.
• The loss in the weight is due to the volatile matter evolved as a result of decomposition
of coal plus moisture that was already present in the coal as such and was measured in
the moisture test.
• The measured moisture content is being subtracted from the total loss in weight as
observed during volatile matter test and is reported as volatile matter less moisture.
Weight of sample (air dried coal) = W1 = g.
Weight of sample after heating = W2 = ____________g
Loss in weight W3 = (W1-W2) = _________g.
%Age Volatile matter (including moisture) M2= (W3/W1) × 100 = __________ %
%Age volatile matter (less moisture) = M3 = M2 – M1 = __________ %
ASH
PROCEDURE
• Take a crucible and tare it till a constant weight is obtained.
• Take 1 g. of air dried sample (-72 BS) in crucible.


• Heat the sample in the furnace at about 800 C° till all the organic matter has been
burned away (ensuring complete combustion in gentle current of air) usually half to
one hour.
• The residue of inorganic matter is weigh as ash.
OR
• First heat the sample at 400 ∼ 450 C° for 30 min after which incineration is completed
by heating the sample at 775 ± 25 C° for one hour. (Initial rate of combustion is kept
slow because some coal turned to spit or decrepitates).
• Thus FBR (fuel research board) have found that employing two stages heating, better
results are obtained due to reduced decapitation of coal.
OBSERVATION AND CALCULATIONS
Weight of sample (air dried coal) = W1 = ____________ g.
Weight of sample (after heating) =W2 =_____________ g.
Loss in weight = W3 = (W1-W2) =___________g.
%age ash (including moisture) M4= (W3/W1)×100 =__________%
FIXED CARBON
PROCEDURE
• It is the solid carbonaceous residue (other than ash) resulting from volatile matter test.
Its value is calculated by subtracting moisture, volatile matter and ash from 100%.
• It brings the total of the proximate analysis automatically 100%.
%Age fixed carbon = 100 − (M1+M3+M4)
%Age fixed carbon = 100 − (M1+M2+M3)=____________%
M5 = 100 − (M1+M3+M4) = ___________%


RESULTS
The complete analysis
1. % Age moisture content ___________.
2. % Age volatile matter less moisture ___________.
3. % Age ash ___________.
4. % Age fixed carbon _________.
DISCUSSION ON RESULTS


LUBRICATING OIL ANALYSIS
Theory
VISCOSITY
Viscosity is the measure of the internal friction of a fluid. These frictions become apparent
when a layer of fluid is made to move in relation to another layer. The greater the friction,
the greater the amount of force required to cause this movement. This is called “shear”.
Shearing occur whenever the fluid is physically moved or distributed, as in pouring , or
spreading, spraying, mixing etc. highly viscous fluid therefore, required more force to
move then less viscous materials.
Isaac Newton defines viscosity by considering the model represented in the figure above.
Two parallel planes of fluids of equal area ‘A’ are separated by a distance, ‘dx’ and are
moving in the same direction at different velocities V1 and V2.
Newton assumed that the force required maintaining this difference in speed was
proportional to the difference in speed through the liquid, or the velocity gradient. To
express this, Newton wrote
ɳ


Where ɳ is viscosity
The velocity gradient dv/dx is a measure the change in speed at which the intermediate
layers move which respect to each other. It describes the shearing the liquid experiences
and is thus called, “shear rate”. This would be symbolized as “S” in subsequent
discussions. Its unit of measure is called the reciprocal seconds (Sec-1
).
The term F/A indicate the force per unit area required to produce the shearing action. It is
referred to as “shear stress” and will be symbolized by “F”. Its unit of measurement is”
Dyne per square centimeter” (dyne/ cm2
).
Using these simplified terms, viscosity may be defined mathematically by the following
formula
ɳ = viscosity =
SI symbol ɳ,
UNITS
The fundamental unit of viscosity is “Poise”
Definition of poise:
A material requiring a shear stress of 1dyne/cm2
to produce a shear rate of one reciprocal
second has a viscosity of 1poise.
S.I units:
Pascal-seconds (Pa.s) or milli Pascal-seconds (m pa.s)
Units Conversion:
1Pa.s = 10 Poise
1m Pa.s = 1cp
APPARENT VISCOSITY
The ratio of shear stress to rate of shear of a non-Newtonian fluid such as lubricating
grease, or a multi-grade oil, oil calculated from Poiseuille’s equation measured in poises.


The apparent viscosity changes with changing rates of shear and temperature must,
therefore be reported as the value at a given shear rate and temperature
Definition:
The value obtained by applying the instrumental equation used in obtaining the viscosity
of Newtonian fluid to viscometer measurement of a non-Newtonian fluid.
NEWTONIAN FLUID
A Newtonian fluid is a fluid whose stress versus strain curve is linear and passes through
the origin. The constant of proportionality is known as the viscosity.
A simple equation to describe Newtonian fluid behavior is
Ƭ= µ
Where
Ƭ = shear stress [Pa] (F/A) exerted by the fluid “Drag” Fluid resistance
Drag “some times called air resistance or fluid resistance” refer to force which act on a
solid object in the direction of relative fluid flow velocity. Drag forces depend on
velocities. Drag force is always decrease fluid velocity relative to solid object in the fluid’s
path.
µ = Fluid viscosity s constant of proportionality Pa-s.
Velocity gradient perpendicular to the direction of shear, or strain rate [S-1
]
In common terms, this means the fluid continues to flow regardless of the force acting on
it. For example water is Newtonian because it continues to exemplify fluid properties no
matter how fast it stirred or mixed.
Other example may be aqueous solutions emulsions contrast this with a non-Newtonian
fluid in which stirring can either leave a “Hole” behind (that gradually fills up over time-
this behavior is seen in materials such as pudding or to a less rigorous extent, sand).


Graphically: A Newtonian fluid is represented graphically in the relationship between
shear stress (F) and shear rate(S) is a straight line. Graph B shows that fluid’s viscosity
remain constant as the shear rate is varied. Typical Newtonian fluids include water thin
motor oils, air, ethanol and benzene. All gases are Newtonian
What this means in practice is that at a given temperature the viscosity of a Newtonian
Fluid will remain constant regardless of which viscometer model you use to measure it.
Newtonians are obviously the easiest fluid to measure –just grab your viscometer and go
for it. They are not unfortunately as common as that much more complex group of fluid,
the non-Newtonian Fluids
NON – NEWTONIAN FLUID
A fluid that does not obey the Newtonian relationship between the shear and shear rate is
called Non-Newtonian fluid.
The subject of rheology is devoted to the study of the behavior of such fluids. High
molecular weight liquids, which fine particles are suspended (slurries and pastes) are
usually Non-Newtonian. In this case, the slope of the shear stress verses shear rate curve
will not be constant as we change the shear rate
Two Cases:
Case 1: when the viscosity decreases with increasing shear rate, we call the fluid shear
thinning.


Case 2: When the viscosity increases as the fluid is subjected to a higher shear rate, the
fluid is called Shear-Thickening
Details of Case 1:
Shear-Thinning behavior is more common then Shear-Thickening. Shear-thinning fluids
also are called Psendoplastic fluid. A typical shears stress versus shear rate plot for a
Shear-Thinning fluid look like this
We describe the relationship between shear F and shear rate S as follow
F = S
Where is called the apparent viscosity of the fluid and is a function of the shear rate.
Many Shear-thinning fluids will exhibit Newtonian behavior at extreme shear ratesboth
low and high.
Examples of Shear-Thinning fluids are polymer melt such as molten polystyrene, polymer
solution such as polyethylene oxide in water and paints.
Details of Case 2:
Some slurries and paste exhibit an increase in apparent viscosity as the shear rate is
increased. They are called Shear-Thickening or dilatants fluids typical plot of shear stress
versus shear rate is shown below


Some examples of shear-Thickening fluids are corn starch, clay, slurries and solutions of
certain surfactants.
“Most Shear-Thickening fluid tend to show shear-thinning at very low shear rates”
Another type of Non-Newtonian fluid is a viscoplastic “Yield Stress” fluid. This is a fluid
that will not flow when only a small shear stress is applied; the shear stress must exceed a
critical value known as they liked stress ◦ for the fluid to flow, e.g. Toothpaste.
Viscoplastic fluid behaves like solids when the applied shear stress less then the yield
stress. Once it exceeds the yield stress the viscoplastic fluid will flow just like an ordinary
fluid.
Bingham plastics are a special class of Viscoplastic fluids that exhibit a linear behavior of
shear stress against shear rate. Typical viscoplastics behaviors are illustrated in next
figure.


LAMINAR AND TURBULENT FLOW:
The very definition of viscosity implies the existence of what is called “laminar flow”, the
movement of one layer of fluid past another with no transfer of matter from one to the
other. Viscosity is the friction between these layers. Depending on a number of factor s.
there is a certain maximum speed at which one layer of fluid can move with relation to
another, beyond which an actual transfer of mass occur. This is called “turbulence”
molecules of larger particles jump from one layer to another and dissipate a substantial
amount of energy in the process. The net result is that a larger input is required to maintain
this turbulent flow than a laminar flow at the same velocity. The increased energy input is
manifested as an apparently greater shear than would be observed under laminar flow
conditions at the same shear rate. This results in an erroneously high viscosity reading.
The point at which laminar flow evolves into distinguishes between turbulent flow
condition and factors besides the velocity at which the layers move. A material’s viscosity
and specific gravity as well as the geometry of the viscometer spindle and sample
container all influence the point at which this transition occurs.
Care should be taken to distinguish between turbulent flow condition and dilatant flow
behavior. In general, dilatant materials will show a steadily increasing viscosity with
increasing shear rate; turbulent flow is characterized by a relatively sudden and substantial
increase in viscosity above a certain shear rate. The material’s flow behavior may be
Newtonian or non-Newtonian below this point.
FACTOR THAT AFFECT THE VISCOSITY:
1. Size and structure of molecule:
Viscosity increases with increase in size and structure of molecules.
2. Intermolecular forces of Attraction:
Viscosity increases with increases in Intermolecular forces of Attraction. e.g. H2O is
more viscous than alcohol.
3. Effect of Temperature:
In liquids, Viscosity decreases with increases in Temperature as Intermolecular forces
of Attraction are decreased & K.E increased.


4. Density:
Greater the density greater will be the viscosity of liquid.
HOW VISCOSITY IS MEASURED IN LABs:
It is measured by Oswald Viscometer.
ATCOMMERCIAL SCALE:
Commercially it is measured by three makes of commercial viscometers:
• Redwood viscometer (Used in common wealth countries).
• Saybolt viscometer (Used in U.S.A).
• Engler viscometer (Used in Europe).
PRINCIPLE OF ABOVE VISCOMETERS:
“A FIXED volume of a liquid at fixed temp is allowed to flow through a STANDARD
capillary tube & the time of flow is noted”.
The results are sometimes expressed in terms of time by taken oil to flow through a
particular instrument e.g.
Viscosity=100 Redwood sec at 20˚C
Kinematic viscosity is measured by this method is expressed in stokes or centistokes.
Kinematic viscosity of liquid fuel is given by
ɳ = AT-
Where
T = Time of flow of oil (at a fixed temp) through the viscometer. A andB are viscometer
constants and depend upon the dimensions of the viscometer capillary through which oil
flows.
For Redwood viscometer No.1, T is the time of flow of 50 c.c. of oil and values of
constants B and A for various values of T are given in Table
Table: Values of REDWOOD VISCOMETER CONSTANT
Values of T Values of B Values of A
34-100 Seconds 1.78 0.0026
>100 seconds 0.50 0.00247


Redwood Viscometer I is used for low viscosity oils whereas Redwood Viscometer II is
used for highly viscous oil (its oil flow port area is larger). The value of constants A and
Bare different for the two viscometers as their flow port diameter are different. These
values are supplied with the viscometers. No of seconds required for flow of fixed quantity
of oil (usually 50c.c. at a fixed temp) is a measure of viscosity. High viscosity oil takes
longer time to flow out.
The commonly used method measure the viscosity in Arbitrary Units. The time required
for a standard volume of oil to flow through a standard Orifice is measured and the
viscosity is stated is as a number of seconds at a certain temperature as measured by a
named apparatus.
In British practice, the standard instrument for measuring viscosity is Redwood
viscometer. It consists of metal cup with an axially-placed orifice in the base. The hole can
be closed by a metal ball or a rod, the metal cup can be heated and the oil is stirred to
ensure uniform temperature conditions. When the ball is removed,a thin stream of oil runs
into a small graduated glass flask and the time to fill the flask is recorded which represents
the viscosity of oil. Two types of redwood viscometer are used. No. 1 is used for less
viscous oils and No.2 is used for more viscous oils. The time required for a standard
volume of oil to flow from Redwood no. 2 viscometer is of that required for an
equal volume of same oil at the at the same temperature to flow from the redwood No.1
viscometer .viscosities measured by the Redwood Viscometer are reported as “n seconds
Redwood No. (1 or 2) at a given temperature.
Kinematic viscosity (expressed in Stokes/centistokes) is related to absolute/dynamic
viscosity (expressed as poise/centipoise) as
ɳ =
Where,
= Density of oil, gm/cm3
µ = absolute viscosity of oil, poise = gm/cm.sec
ɳ= Kinematic viscosity, stokes


Saybolt universal and Saybolt Furol are similarly different viscometer used for different
viscosity oils.
In American practice, Saybolt viscometer is used. Similar to Redwood Viscometer No. 1
and No. 2, Saybolt also used two standard, i.e. Saybolt universal viscosity(time taken in
second for 60 ml of sample flowing through a calibrated universal orifice under specified
conditions) and Saybolt Furol viscosity (time taken in second for 60 ml of sample flowing
through a calibrated Furol orifice under specified conditions).
The Furol viscosity is approximately one- tenth the universal viscosity and is
recommended for those liquids having viscosities more than 1000 seconds (Saybolt
universal), such as fuel oils and other residual materials. The word ‘Furol’ is a contraction
of fuel and road oils.
In the Engler Viscometer shown, the water-bath is heated by gas –ring and its
temperature is kept uniform with the help of a stirrer. The oil cylinder is fitted with three
gauge points, which indicate the amount of oil to be poured in it and also helps in leveling
the instrument. The loosely fitted oil cylinder cover carries a thermometer which can be
rotated to stir the oil; the jet fitted at the bottom of oil cylinder is slightly tapered. The
valve pin which seats itself on the jet is lifted to start the test and the time of outflow of
flow of 200 c.c. of water at 20˚C is taken as 52 seconds. The viscosity in degree Engler
(˚E) is determined by dividing the time of outflow of 200c.c. of oil by 52 seconds (which
is the time of out flow of corresponding volume of 200 c.c. of water).
Data of one standard is converted to another by following
Equivalence of 1 centistokes
= 4.08 Seconds – Redwood I
= 0.408 Seconds – Redwood II
= 0.131 degree Engler
= 4.57 seconds Saybolt universal
=0.457 seconds Saybolt Furol


Table kinematic Viscosity ( ) conversion formula
Viscosity Scale
Range of Flow Time, T,
seconds
Kinematic viscosity,
stokes
Saybolt Universal
T = 32 to 100
T = > 100
0.00226 T– 1.95/T
0.00220 T – 1.35/T
Saybolt Furol
T= 25 to 40
T= > 40
0.0224 T – 1.84/T
0.0216 T – 0.60/T
Redwood No I
T = 34 to 100
T = > 100
0.00260 T – 1.79/T
0.00247 T – 0.50/T
Redwood Admirality
(II)
– 0.027 T – 20/T
Engler – 0.00147 T – 3.74/T
WHY VISCOSITY OF LUBE OIL IS NEEDED TO MEASURE:
Viscosity of fuel oils influences the ease of handing, transport and nature of storage. Oil
viscosity affects its atomization and combustion efficiency. Preheating of fuel oil is done
to reduce the viscosity (above 120˚C viscosity is almost constant) to achieve better
atomization (finer oil droplet for better combustion). Maximum viscosity for easy
atomization in conventional burner is 25 centistokes (100 sec Redwood I). For easy and
economic pumping the maximum viscosity should be 1200 centistokes (486 sec Redwood
II) at higher preheating temperature of oil, the decrease viscosity facilities easy flow and
better atomization in the burner. Hence, beyond an optimum oil preheating temperature,
the burner capacity is reduce.


In case of diesel fuel, too low viscosity causes excessive leakage at the injection pistons
while to high viscosity produces coarse oil droplets which form engine deposit due to
incomplete combustion.
Viscosity of oil blends is experimentally determined (as viscosity is not an additive
property or calculated with the help of empirical blending charts).
At high pressure, viscosity of oil increases versus rapidly. At 70atm pressure, viscosity
increases by 15%. Most oils begin to solidify at 3500 kg/cm2
pressure.
Viscosity Index (V.I):
The viscosity of a liquid decreases with increase in temperature. The change in viscosity
with change in temperature is expressed by viscosity index. It is an empirical number
indicating the rate of change of viscosity of oil from 100˚F to 210˚F. Low viscosity index
means a large change in viscosity with change in temperature. A high viscosity index
shows relatively small change in viscosity with temperature.
Paraffinic oil has very high viscosity index = 100
While naphthenic oil has very low viscosity index=0 (These are arbitrarily assigned values
for a standardization).
Viscosity index of an oil is determined by measuring its viscosity at two temperature and
comparing the results with those for a standard oil of V.I = 100 and for a standard oil of
V.I = 0
Viscosity Index =
Where U =viscosity of oil sample at 100˚F
L = viscosity of standard oil of V.I. = 0 at 210˚F
H = viscosity of standard oil of V.I. =100 at 210˚F
Value of L and H are obtained from table after the viscosity of sample has been
determined at 100˚F
Viscosity Index measures the paraffinity of oil. Lubricating oil should in general have high
viscosity index. Viscosity index improvers (e.g. polybutene) are used for improving it.


High V.I oils are used where there is a wide temperature variation. High V.I. lubricating
oils are called multigrade oils.
Engler Viscometer
Theory
APPARATUS DISCRIPTION
The Engler Viscometer is mainly used in Germany .It generally measures the viscosity of
oil. It is the viscometer with tumultuous relative regimens and it measure the viscosity
referred to the water. It is showed in Engler Degree and represents the ratio between the
down flow time in seconds of 200ml of the sample through to calibrate capillary hole and
the 200 time taken by milliliter distilled water.
BASIC PARTS OF THE VISCOMETER
Thermostat: (A)
The basic function of the thermostat used in this apparatus is to maintain the constant
temperature for the heating of oil taken in the bath placed within the thermostat Bath
Thermostat bath is made of Brass and servers the required temperature.
Thermostat is arranged coaxially to the first one and it is equipped with thermometer and
agitator to shovels to set in action by hand. In this container the heating liquid comes place
that it will have to carry the oil to the temperature of test.
Thermometer: (B)
There are two thermometer are used in this apparatus One is placed in the oil bath for the
measurement of the temperature of the oil used The second thermometer is placed is the
Thermostat bath which shows the temperature is then can be adjusted.
Cover: (C)
The container is fortified of wall cover double with two holes one for thermometer that
measure the temperature of the liquid and the other for a valve pin in wood, in order to
close the outflow hole.


Valve: (D)
The valve pin passed through the cover and seats in the discharge pipe. When the pin is
lifted the oil start flowing through the platinum discharge tube and time of flow of 200ml
of oil is measure.
Stirrer: (E)
Stirrer is use for the uniform distribution of the heat supplied to the fuel placed in the
metal bath.
Jet: (F)
The oil container is constituted from brass metal with to the centre of the base a hole,
communicating with a small calibrated with platinum capillary through wish the liquid
will have to flow down. The capillary allows the oil to flow through it and time a flow of
oil is used for the measurement of viscosity.
Level Gauge: (G)
Three needle point gauges are fixed in the oil bath placed to 120O
one from the other, mark
it the level that must catch up the liquid for measuring the oil on the one hand, and on the
other to serve for the correct adjustment of the horizontal position of the apparatus.
Leveling Screw: (T)
Leveling screw is used for the correct horizontal position of the viscometer and it also help
in keeping the correct level of the oil in the bath.


U
P
B
D
C
A
E
J
T T
G G
ENGLER VISCOMETER
ARRANGMENT OF APPARATUS:
It consists of two metal basins, one placed within the other, one serving as an oil reservoir
and the other as a thermostat. The oil bath is fixed in to the thermostat by support and by
the discharge pipe F .A valve pin D passed through the lid and seats in the discharge pipe.
Three needle-point gauges are fixed in the oil bath equidistance from the bottom for
measuring the oil on one hand and the other to serve for the correct adjustment of
horizontal position of the apparatus .when the oil bath is filled to gauge level it should
contain 240ml.A tripod supports the apparatus .A measuring flask having on its neck two
marks, one registering 200ml, the other 240ml, is placed under the platinum discharge
tube when a determination to be made.
To test the correctness of the apparatus the time taken for 200ml of water at 20˚C flow out
of the bath and is filled to gauges, is noted. Before removing the valve the water should be
allowed to acquire a state of rest after being stirred by rotating the lid with the
thermometer in position. Exactly time same procedure is adopted when the oil is being
tested.


Experimental Work
OBJECTIVE
a) Determine the Kinematic Viscosity of the given sample of lubricating oil at room
temperature 35o
C, 45o
C, 55o
C, 65o
C using Engler Viscometer.
b) Report the dynamic viscosity(at above temperatures) and degree Engler (˚E)
c) Using Viscosity conversion Nomogram find the equivalent of kinematic viscosity in
Saybolt Universal seconds, Redwood No.1 seconds, Redwood No. 2 seconds and
Engler Degree.
d) Report the difference of experimental and observed (the one which you get from
Nomogram) Degree Engler o
E.
e) Plot the graphs relating
i. Temperature vs. Kinematic Viscosity
ii. Temperature vs. Time of flow
iii. Kinematic Viscosity and Time of Flow
f) Develop an equation of kinematic viscosity (stokes) and time of flow (seconds) curve
using MATLAB or POLYMATH or MS Excel or MathCAD.
g) Report the comparison of coefficients of developed equation with coefficients of
standard equation. (At any arbitrary value).
APPARATUS:
Thermometer, Beaker, Specific Gravity Bottle and Engler Viscometer
PROCEDURE:
• Clean the oil cup with soft tissue to remove any oil already present in cup.
• Pour the water in the cup to filling marks, keeping pointed rod in the vertical position
(and cover up) which act as ball valve to close the orifice.
• When cup has been filled with water up to the level gauge, lower the cover and insert a
thermometer into the cup (make sure the vertical rod is closing the orifice when you
cover down the cup).
• Collect 200ml of water in the beaker (after placing beaker beneath the orifice) and note
the time to out flow (in seconds) at room temperature by up lifting the vertical Rod.


• Repeat the same procedure with the sample of oil and measure the time of flow for
200ml of oil sample.
• Heat the sample to achieve the required temperature and note the time (seconds) of
outflow of sample at 35o
C, 45o
C, 55o
C, and 65o
C respectively.
PRECAUTIONS:
• DO NOT SWITCH ON THE THERMOSTATE/HEATER WITHOUT WATER
IN WATER BATH.
• Make sure the temperature for flow of water and for oil sample is the same.
OBSERVATION AND CALCULATION:
Room Temperature T1 = ___________________ oC
Density of water at T1, d1 = _____________________o C
Sr.
No
Set
Point
oC
Temperature
Attained ˚C
T2
Time to
flow t(Sec)
Degree
Engler
˚E
Kinematic
Viscosity
(Stokes)
Density
of oil at
T2 d2
Dynamics
Viscosity
(poise)Water Oil
01*
02
03
04
05
*Perform 1st
reading at room temperature
FOR DEGREE ENGLER:
˚E =
KINEMATIC VISCOSITY:
V = 0.08˚E – (0.0864 / ˚E)
Where ˚E = 1.35 to 3.2
And for o
E> 3.2V =0.076˚E – (0.04 / ˚E)
Similarly


V = 0.00147 × t – (3.74/t)
FOR DYNAMIC VISCOSITY:
For dynamic viscosity (at temperature T) determine sp. Gravity of oil sample (at
temperature T) and density of oil sample (at temperature T)with sp. gravity bottle method
Sp. Gravity of oil = = (
Density of oil = Sp. gravity of oil × density of water (at temperature T)
Dynamic Viscosity of oil = Kinematic Viscosity × density of oil
c) Equivalent of kinematic viscosity in Saybolt Universal seconds, Redwood No.1
seconds, Redwood No. 2 seconds and Engler Degree using Viscosity Conversion
Nomogram
Sr. No.
Kinematic
Viscosity
(centistokes)
Saybolt
Universal
Seconds
Redwood
Number 1
seconds
Redwood
Number 2.
Seconds
Engler
Degrees
(observed)
1 Stoke = 100 centi-stoke; 1 Poise = 100 cp
d) Report the difference of experimental and observed (the one which you get from
Nomogram) Degrees Engler o
E.
Sr. No. Experimental Degree
Engler o
E (A)
Observed Degree
Engler o
E (B)
A-B / B-A


e) Graph:
Kinematicviscosity
Time of Flow
The equation of this trend
line will provide the
experimental equation for
Engler Viscometer
f) Equation of kinematic viscosity (stokes) vs. time of flow (seconds) curve using
MATLAB or POLYMATH or MS Excel or MathCAD.
__________________________________
g) Comparison of coefficients of developed equation with coefficients of standard
equation. (At any arbitrary value).
Sr. No. Standard Equation
Coefficients (A)
Developed Equation
Coefficients (B)
A – B/ B-A


GRAPH:
RESULT:
DISCUSSION ON RESULTS:
BROOKFIELD VISCOMETER


Brookfield Viscometer
Theory
HOW THE BROOKFILED VISCOMETER WORKS
The Brookfield Viscometer is of the rotational variety. It measures the torque required to
rotate an immersed element (the spindle) in a fluid. The spindle is driven by a motor
through a calibrated spring; deflection of the spring is indicated by a pointer and dial (or a
digital display). The viscous drag of the fluid against the spindle is measured by the spring
deflection.
The measurement range of a DV – E (in centipoises or millipascal seconds) is determined
by the rotational speed of the spindle, the size and the shape of the spindle, the container in
which the spindle is rotating, and the full scale torque of the calibrated spring. By utilizing
a multiple speed transmission and interchangeable spindles, a variety of viscosity ranges
can be measured, thus enhancing versatility of the instrument.
Mechanism of Viscometer:
For a given viscosity, the viscous drag, or resistance to flow (indicated by the degree to
which the spring winds up), is proportional to the spindle’s speed of rotation and is related
to the spindle’s size and shape (geometry). The drag will increase as the spindle size
and/or rotational speed increase. It follows that for a given spindle geometry and speed, an
increase in viscosity will be indicated by an increase in deflection of the spring. For any
Viscometer model, the minimum range is obtained by using the largest spindle at the
highest speed; the maximum range by using the smallest spindle at the slowest speed.
The Viscometer is composed of several mechanical subassemblies. See Figure 1 for a
schematic view of the major components of a basic dial-reading Viscometer.


Figure 1
The stepper drive motor (which replaced the synchronous motor and multiple-speed
transmission) is located at the top of the instrument inside the housing to which the
nameplate is attached. The Viscometer main case contains a calibrated beryllium-copper
spring, one end of which is attached to the pivot shaft, the other end is connected directly
to the dial. This dial is driven by the motor drive shaft and in turn drives the pivot shaft
through the calibrated spring. In dial reading models, the pointer is connected to the pivot
shaft and indicates its angular position in relation to the dial. In Digital models, the relative
angular position of the pivot shaft is detected by an RVDT (rotary variable displacement
transducer) and is read out on a digital display.
Below the main case is the pivot cup through which the lower end of the pivot shaft
protrudes. A jewel bearing inside the pivot cup rotates with the dial or transducer; the
pivot shaft is supported on this bearing by the pivot point. The lower end of the pivot shaft
comprises the spindle coupling to which the Viscometer’s spindles are attached.


HOW TO MAKE SELECTION OF SPINDLE
When performing a test according to an existing specification or procedure, use the
spindle and speed specified. When conducting an original test, the best method for spindle
and speed selection is trial and error. The goal is to obtain a Viscometer display (% torque)
reading between 10 and 100, remembering that relative error of measurement improves as
the reading approaches 100. If the reading is over 100, select a slower speed and/or a
smaller spindle. Conversely, if the reading is under 10, select a higher speed and/or a
larger spindle. If the approximate viscosity of the sample fluid is known, a faster method
for honing in on the right spindle/speed combination is available by referring to the Factor
Finder supplied with the Viscometer. The goal is to select a combination whose range
brackets the estimated viscosity of the sample.
For any given spindle/speed combination, the maximum range available is equal to the
spindle Factor multiplied by 100. This maximum is also called “Full Scale Range” or
“FSR”. For Digital Viscometers that have the AUTORANGE key, selecting a speed and
spindle and then depressing and holding the AUTORANGE key will cause the screen to
display FSR in cP (mPa•s).
The minimum recommended range equals the Factor multiplied by 10. For example: a #2
spindle on an LVT Viscometer at 12 RPM has a Factor of 25. The maximum range of this
combination is 25 times 100, or 2500 cP. The minimum recommended viscosity that
should be measured is 25 times 10, or 250 cP. Therefore, if the viscosity of the sample
fluid is estimated to be 4000 cP, another spindle/ speed combination must be selected in
order to make the measurement. If the sample fluid is around 2000 cP, however, this
spindle and speed would be suitable. With a little practice, a quick glance at the Factor
Finder will suffice to make an appropriate selection of spindle and speed. When
conducting multiple tests, the same spindle/speed combination should be used for all tests.
When a test must be performed at several speeds, select a spindle that produces on-scale
readings at all required speeds. This may necessitate using a display reading less than 10,
which is acceptable as long as the reduced accuracy of such a reading is recognized.
There are four basic spring torque series offered by Brookfield:
Spring Torque
Model Dyne-cm Milli Newton-m
LVDV-E 673.7 0.0673
RVDV-E 7187.0 0.7187


HADV-E 14374.0 1.4374
HBDV-E 57496 5.7496
The higher the spring torque, the higher the measurement range. The viscosity
measurement range for each spring torque is listed below
Viscosity Range (cp)
Viscometer Minimum Maximum
LVDV-E 15 2 M
RVDV-E 100* 13 M
HADV-E 200* 26 M
HBDV-E 800* 106 M
• *Minimum viscosity with optional RV/HA/HB- spindle
cp = Centipoise M = 1 million = 1,000,000
All units of measurement are displayed according to either the CGS(cP) system or the SI
(mP.s) system
1. Viscosity appears in units of centipoises (shown as “cP”) or milliPascal-seconds
(shown as “mPa.s”) on the DV-E display.
2. Torque appears in units of dyne-centimeters or Newton-meters (shown as percent
‘%” in both cases) on the DV-E display.
Sample Container Size
For measurements with standard Viscometer models manufacturer recommends a
container with an inside diameter of 3 1/4 inches (83 mm) or larger. The usual vessel for
this purpose is a 600 mL low form Griffin beaker. Use of a smaller container will result in
an increase in viscosity readings, particularly with the #1 and #2 spindles. When utilizing
a smaller container, the simplest approach is to report the dimensions of the container and
ignore the probable effect on calibration. As long as the same size container is used for all
subsequent tests, there will be no correlation problem.
Sample Conditions (give bullets)
The sample fluid should be free from entrapped air. Air can be removed by gently tapping
the container on a table top or by careful use of a vacuum apparatus. The sample should be
at a constant and uniform temperature. This can be verified by checking the temperature at
several different locations within the container. Be sure to bring the sample, spindle, and
guard-leg to the same temperature before taking a viscosity reading. Temperature


uniformity can often be maintained by agitation prior to a measurement, but first
determine that such agitation won’t affect viscosity of the sample fluid. Factors used to
calculate viscosity values from the Viscometer readings are independent of temperature. A
constant temperature water bath may be used to maintain the desired temperature.
Homogeneity of the sample is also quite important, especially in dispersed systems where
settling can occur. In many cases, simple stirring just prior to the test will keep the
components dispersed.
Spindle Immersion
The spindle should be immersed up to the middle of the shaft indentation (notch). Failure
to do so could result in incorrect viscosity readings. In some cases the sample fluid may
change its rheological structure during the act of spindle immersion. To avoid this, insert
the spindle in a different portion of the sample than the one intended for measurement.
The spindle may then be moved horizontally to the center of the sample container. This
must be done before attaching the spindle to the Viscometer.
Sensitivity and Accuracy
Brookfield Viscometers are guaranteed to be accurate to within 1% of the full-scale
range of the spindle/speed combination in use (this percentage, expressed in centipoise
values, is equal to the spindle Factor; accuracy of a spindle/speed combination with a
factor of 25 would therefore be within 25 cP). Repeatability is to within 0.2% of the
full scale range. The relative error of a particular viscosity reading is dependent upon the
actual display (% torque) reading. In general, relative error of the viscosity value will
improve as the reading approaches 100. This is because the tolerance of 1% of full scale
viscosity applies to all readings, and represents a smaller percentage of measured viscosity
as the actual reading increases.
Viscometer
Reading
Viscosity Possible Error Relative Error
100 10cp 1 cp 1%
50 50cp 1 cp 2%
10 10cp 1 cp 10%
BROOKFIELD VISCOMETER
The equivalent units of measurement in the SI system are calculated using the following
conversions:


Name of Property SI CGS
Viscosity 1mPa.s 1Cp
Torque 1Newton-m 107
dyne-cm
Reference to viscosity throughout this manual is made in CGS units. The LVDV-E
viscometer provides equivalent information in SI units.
Components:
• DV-E viscometer
• Model a Laboratory stand
• Spindle set with Case:
• Guard Leg
• Shipping Cap
:
Instrument Controls:
The following describes each switch’s function:MOTOR ON, Turn the motor ON or OFF


AUTO RANGE
Present the maximum (100% torque) viscosity attainable using the selected spindle at the
selected speed. This value is referred to as full scale range. The allowable error for the
viscosity measurement is ±1% of full scale range.
Note; Pressing and holding the AUTO RANGE key during power on will enable the
viscosity display to be either CGS (cP) or SI (mPa.s) units.
SPEED/SPINDLE SWITCH
It sets the viscometer in either speed select or spindle select mode when set in the left
position, the operator may select speed of rotation, when set in the right position, the
operator may select the spindle.
Note:
This is three (3) position switches. We recommended that the switch be set to the middle
position when finished with spindle or speed adjustment. This will prevent an accidental
change of parameters during a test.
SELECT KNOB
This knob is used to scroll through the available speed or spindle selection (see table CI in
Appendix C). This knob is active when the switch is set t the let (speed) or right (spindle)


position. Rotate the knob clockwise to increase value and counter-clock wise to decrease
value.
GETTING STARTED
Power up
Turn the power switch (located in the rear panel) to the ON (I) position. This will result in
the following screen display
After a few seconds the following screen appears:
After a short time, the display will clear and the default screen like below is displayed:
Spindle Selection
LVDV-E Viscometer is provided with a set of four spindles and narrow guard-leg.The
spindles are attached to the viscometer by screwing them to the male coupling nut. Note
that the spindles and coupling have a left-hand thread. The lower shaft should be held in
one hand (lifted slightly), and the spindle screwed to the left. The face of the spindle nut
and the matching surface on the coupling nut shaft should be smooth and clean to prevent
eccentric rotation of the spindle. Spindles can be identified by the number on the side of
the spindle coupling nut.
Setting the SPEED/ SPINDLE switch to the right position will allow the operator to adjust
the spring selection, The SELECT knob can be rotated until the desired spindle number is


selected. Once the desired spindle number is shown on the display, Set the
SPINDLE/SPEED switch to the middle position.
Speed Selection & Setting:
There are 18 rotational speeds available on the DV-E Viscometer. These speed correspond
to the standard LVF, LVT,RVF, RVT, HAT and HBT Dial Viscometer models and they
are combined sequentially, see Table Below.
Setting the SPEED/SPINDLE switch in the left position will allow the operator to adjust
the speed selection. The select Knob can be rotated until the desired speed is selected.
Once the desired speed is shown on the display set the SPINDLE/SPEED switch the
middle position.
The viscometer will rotate the spindle at the selected speed when the motor switch is in
ON position. A motor on condition is indicated on the display by RPM shown beside the
speed. When the motor is in the OFF position, OFF will be displayed beside the speed
Auto range and CGS or SI Unit Selection
The AUTO RANGE key allows you to determine the maximum calculated viscosity (full
scale reading) possible with the current spindle/speed setting. Pressing the key at any
time will cause the current viscosity display to change and show that maximum viscosity.
Screen Torque display will now display”%100” to indicate this special condition. This


maximum viscosity and % 100 values will be display for as long as the AUTO RANGE
key is depressed in figure shows the AUTO RANGE function for the situation where the
No. 2RV spindle is rotating at 10 RPM. The full scale range is 4000 cP (or 4000mPa.s)
Pressing and holding the AUTO RANGE key during power on will enable the viscosity
unit displayed to toggle between CGS (cP) and SI (mPa.s) snits. To change the unit
format:
1. Turn the power off
2. Press and hold the AUTO RANGE key and turn the power ON
CGS SI
Viscosity: cP mPa.s
1cP= 1mpa.s
TROUBLE SHOOTING
The DV-E gives indication for out of specification or out-of-range operation. When %
torque readings exceed 100.0% (over range, the display changes to that shown in figure
You must either reduce speed or use a larger size spindle to correct this condition. if you
operate at spindle speeds that produce % (torque) below 10.0% (under-range), the DV-E
displays both %(Torque) and cP (viscosity) with flashing units designation. You must
either increase speed or use a larger size spindle to correct this condition.
The parameter of %(Torque) and cP(viscosity) will also flash prior to one complete
spindle revolution. It is not recommended that readings are taken while parameters are
flashing.


Negative % (Torque) will be displayed as shown in figure. Viscosity value will be
displayed as “----” when the % (torque) is below zero.
Experimental Work
OBJECTIVE:
a) Determine the Dynamic Viscosity of the given sample of lubricating oil at room
temperature, 25o
C, 30o
C, 35o
C and 40o
C using Brookfield Viscometer
b) Report the Kinematic Viscosity at above temperatures.
c) Using Viscosity conversion Nomogram find the equivalent of kinematic
viscosity in Saybolt Universal second, Redwood No.1, Redwood No. 2 and
Engler Degree.
d) Plot the graphs relating
I. Temperature vs. Kinematic Viscosity
II. Torque produced Vs Kinematic viscosity
III. Torque produced, kinematic viscosity Vs Temperature
APPARATUS:
Thermometer, Beaker, Specific Gravity Bottle, Brookfield Viscometer
PROCEDURE:
1. Insert the center spindle in the test material until the fluid level is at the immersion
groove on the spindle’s shaft. With a disk type spindle, it is sometimes necessary to
tilt the spindle slightly while immersing to avoid trapping air bubbles on its
underside surface. (Brookfield recommends that you immerse the spindle in this
fashion before attaching it to the Viscometer). Be sure that the motor is OFF before
attaching the spindle. Select a spindle and attached it to the coupling nut. Lift the
shaft slightly, holding at firmly with one hand while screwing the spindle on with the
other (note left hand thread). Avoid putting side thrust on the shaft.


2. To make a viscosity measurement, select a speed and follow the instruction in
spindle and speed section. Allow time for the indicated reading to stabilize. The time
required for stabilization will depend on the speed at which the viscometer is running
and the characteristics of the sample fluid. For maximum accuracy, flashing readings
below 10% should be avoided
3. Switch the MOTOR ON/OFF switch to turn the motor “OFF” when changing a
spindle or changing samples, remove spindle before cleaning.
OBSERVATION AND CALCULATION:
Room Temperature = ____________________o
C
Density of Oil at room Temperature = ________________ o
C
Spindle No RPM Torque % Dynamic
Viscosity (cp)
Kinematic
Viscosity
(Stokes)
61
62
63
64
FOR KINEMATIC VISCOSITY
For kinematic viscosity (at temperature T) determine sp. Gravity of oil sample using
density of oil sample (at temperature T) with sp. gravity bottle method
Sp. Gravity of oil = = (
Density of oil = Sp. gravity of oil × density of water
Dynamic Viscosity of oil = Kinematic Viscosity × Density of oil


Kinematic Viscosity of oil =
For Spindle no 61:
No of Observation RPM Torque % Dynamic
Viscosity (cp)
Kinematic
Viscosity
(Stokes)
1
2
3
4
5
6
7
8
9
10
For Spindle no 62:
Viscosity(cp)
Kinematic
Viscosity
(Stokes)
1
2
3


4
5
6
7
8
9
10
For Spindle no 63:
Viscosity (cp)
Kinematic
Viscosity
(Stokes)
1
2
3
4
5
6
7
8
9
10


For Spindle no 64:
No of
Observation
RPM Torque % Dynamic
Viscosity(cp)
Kinematic
Viscosity
(Stokes)
1
2
3
4
5
6
7
8
9
10
c) Equivalent of kinematic viscosity in Saybolt Universal second, Redwood No.1,
Redwood No. 2 and Engler Degree using Viscosity Conversion Nomogram
Sr. No.
Kinematic
Viscosity
(centistokes)
Saybolt
Universal
Seconds
Redwood
Number 1
seconds
Redwood
Number 2.
Seconds
Engler
Degrees
1 Stoke = 100 centi-stoke; 1 Poise = 100 cp


d) Graphs
I. Temperature vs. Kinematic Viscosity
II. Torque produced Vs Kinematic viscosity
III. Torque produced, kinematic viscosity Vs Temperature


DIESELANALYSIS (ANILINE POINT AND
DIESEL INDEX)
Theory
ANILINE POINT
It is the lowest temperature at which the oil is completely miscible with an equal volume
of aniline. It is an aromatic content of oil. Aniline is used in this method, because aniline is
miscible by most of the aromatics. Higher the aniline point lower the aromatics and higher
the paraffin content with very high cetane number making oil suitable for use in diesel
engine.
DIESEL INDEX
The aniline point is the directly proportional to the diesel index by equation high the diesel
index, more satisfactory will be the ignition of the fuel oil and high speed engine and it
should be 50 for medium speed engine, and for normal speed engine it should be about35
and should not be less than 25.
Diesel Index =
CETANE INDEX
The cetane index is an estimation of the cetane number from fuel physical properties such
as the 10%, 50% and 90%boiling point and the API.
KNOCKING
One consequence of the auto ignition temperature relates to the conditions in automobiles
known as Knocking generally, straight chain hydrocarbon have lower auto ignition
temperature than branched chain hydrocarbon. Gasoline has a relatively high auto ignition
temperature and, therefore requires an ignition source (a spark from a spark plug) to
initiate combustion. However, as the engine becomes hot during use, ignition of the fuel
can occur before the spark ignites the fuel. This premature ignition produces a “knocking”


or ”pinging” sound and robs the engine of power, and if it continues, the engine may be
damaged. Since straight chain hydrocarbons in the gasoline boiling range have lower auto
ignition temperatures they have greater tendency to produce knocking than do the
branched chain compound of similar molecular weight
OCTANE NUMBER
Vital that the fuel does not auto-ignite before the flame first reaches it. This cause Knock.
Knock is the most single important parameter which limits gasoline engine efficiency and
power. This is dependent on the spontaneous ignition temperature. SIT is lowest for large
alkenes and higher for aromatics are the best. An octane number is defined for each fuel as
the percentage of iso-octane in an isooctane heptanes mixture which gives the same
knocking tendency as the fuel. Additives such as tetra-ethyl-led (TEL) improve octane
numbers of fuel by suppressing auto-ignition. It is cheaper to produce a high octane
gasoline by the use of TEL instead if increasing the aromatics content.
At the max power of spark ignition engine is determined by the RON. As compression
ratio increases so does power, to the point where auto ignition takes place this is also
dependent on mixture ratio.
Fuel must be burned in vapor phase but is supplied as liquid. If volatility too low, there is
problem with lubrication. If too high, problems with vapor lock. Typical boiling range 30-
150°C.if vapor pressure is too low there may be a problem with vapor lock.
WORKING OF FOUR STROKE ENGINE
In combustion engines the inner energy set free by combustion (e.g. of gasoline or diesel
fuel) is changed partly into mechanical energy. There are several verities of combustion
engine. The most common is the four-stroke Otto engine which was invented by the
German merchant and engineer.
The working mechanism of the four-stroke Otto cycle .the engine cylinder has got two
valves, the intake valves and the exhaust valves, which are opened and closed with a
mechanism (camshaft). A crank move the piston in the cylinder by means of “connecting
rod”
The operation of the engine is divided into four-stroke Otto cycle which are called stroke.


1st
Stroke (Intake)
The piston sucks in the fuel-air –mixture from the carburetor in to the cylinder
2nd
Stroke (Compression)
The piston compresses the mixture.
3rd
Stroke (Combustion)
The spark from the spark plug inflames the mixture. In case of diesel engine ignition takes
place from hot compress air. The following explosion presses the piston to the bottom the
gas is operating on the piston.
4th
Stroke (Exhaust)
The piston presses the exhaust out of the cylinder.
By means of crank shaft the motion up and down is converted into a rotational motion.
Within two rotations of the cranks the engine is operating only during a semi rotation, so
that the engine run evenly, in cars mostly 4- cylinder engines are installed (or also 6-
cylinder engine).
DIFFERENCE BETWEEBN GASOLINE AND DIESEL ENGINE
The main difference between the gasoline engine and the diesel engine are
Gasoline engine intakes a mixture of gas and air, compress it, and ignite the mixture with a
spark. The diesel engine takes in just air .compress it and then injects the fuel into the
compressed air. The heat of the compress air lights the fuel spontaneously.
A gasoline engine compresses at ratio of 8:1 to 12:1, while a diesel engine compresses at a
ratio 14:1 to as high as 25:1. The higher compression ratio of the diesel engine leads to
better efficiency.
Gasoline engine generally use either carburetion, in which the air is and fuel is mixed long
before the air enters the cylinder, or port fuel injection, in which the fuel is injected just
prior to the intake stroke (outside the cylinder). Diesel engines use direct fuel injection –
the diesel fuel injected directly into the cylinder.


Comparison of 2 Strokes Vs 4 Strokes
1. 2 strokes needs a blower and will usually use a supercharger.
2. 2 stroke combustion process not as complete (more pollution).
3. 2 stroke engines weigh less and have higher RPM operating speeds.
4. 4 stroke engines have intake, compression, power, and Exhaust Strokes
5. 2 strokes have power and compression.
6. 2 strokes used more for emergencies, 4stroke used more for propulsion.
APPARATUS DISCRIPTION
a) Test Tube and Cork
Test tube used in aniline point test is approximately 25mm in diameter and 150mm in
length, made of heat resistance glass and fitted with a cork bored to hold the thermometer
centrally and provided with another hole through which the stirrer can operate freely.
b) Stirrer
Stirrer can either can be of metal or glass rod bent at the bottom into a ring of about
15mm diameter at right angles to the main axis.
c) Thermometer
It is used to note the temperature of mixture.
d) Pipettes
It is used to measure the volume of aniline and other compound is of 5ml capacity.
e) Heating and Cooling Bath
Heating media is used to make miscible the liquids and cooling bath is used to cool down
the solution. Ice water, or solid carbon dioxide or acetone can also be used as cooling
media.


It is the lowest temperature at which oil is completely miscible with an equal volume of
aniline. It is the measure of the aromatic contents of the oil, hence a characteristic property
of diesel.
APLLICATIONS OF ANILINE POINT
Since aromatics dissolve aniline (itself an aromatic substance) more readily than paraffins
or iso-paraffins, the higher the aniline point, lower the aromatics and higher the paraffin
content with very high cetane number making the oil suitable for use in diesel engine.
Aniline point of oil also gives an indication of the possible deterioration of rubber sealing,
packing etc. in contact with the oil. The aromatics have a tendency to dissolve natural
rubber and certain types of synthetic rubber. Therefore, in such cases, a low aromatic
content in the lubricant (i.e., with high aniline point) is desirable. Aniline point of cetane is
95o
C and for hexyl benzene is -12o
C.


Hence, higher the aniline point, better the diesel fuel and the lubricant.
Diesel Index: An alternative method of expressing the quality of diesel oil is by use of the
‘Diesel Index’. It is given by
Diesel Index (Z) =
Diesel index is roughly related with cetane number as
Diesel Index = Cetane number + 3
The use of diesel index does not necessitate the use of a test engine for determining the
cetane number and hence the quality of diesel.
Experimental Work
OBJECTIVE
To Determine the Diesel Index of given sample of Diesel Oil via Aniline Point test, also
calculate the Cetane number (approximate) of the sample.
APPARATUS
Thermometer, Beaker, Diesel Sample, Aniline, Stirrer
PROCEDURE
• Take equal volume of Aniline (C6H5NH2) and Diesel sample in a round bottom tube
and sample in a beaker containing water after inserting thermometer and stirrer into it.
• Heat the beaker (water bath) till two separate layers of liquids become miscible with
continuous stirring.
• As soon as the miscibility occurs, the source of heat is removed and apparatus is
allowed to cool down (stirring being continued) till cloudiness appears (during separation
of two layers).
• Note the thermometer reading which indicates the approximate Aniline point.
Or
• Using the automatic Aniline Point tester, heat mixture of Aniline and sample(taken in
equal volumes) with continuous stirring will opaque homogenous solution becomes
transparent by observing it under light bulb.


OBSERVATIONS AND CALCULATIONS
Aniline Point of given sample=T= _______________°F
Diesel Index (Z) =
(for API gravity see API gravity experiment)
As we know for approximate Cetane Number
Diesel Index = Cetane Number + 3
Thus
Cetane Number (Y) = Diesel Index – 3
Results:
Aniline point of given Sample. (T) = ____________________ °F
Diesel Index of given Sample. (Z) = _____________________ .
Cetane Number of given Sample. (Y) = ______________________ .


SPECIFIC GRAVITY MEASUREMENTS
Theory
AMERICAN PETROLEUM INSTITUTE (API) AND SPECIFIC GRAVITY
The specific gravity of oil is the ratio of its weight to the weight of an equal volume of
water.
It is commonly designated as ‘Sp.gr 60/60F’, indicating that both the oil and the water are
weighed and measured at a temperature of 60o
F.
The oil industry uses a scale adopted by The American Petroleum Institute (API) for
measuring the density of fuels, giving readings in degree API. The relationship between
specific gravity and API gravity is
o
API = - 131.5
API gravity is a measure of how heavy or light petroleum liquid is compared to water. API
gravity of water is taken as 10 (Activity: Do you mind to show how this value comes?)
If API gravity of a liquid is greater than 10, it is lighter and floats on water; if less than 10,
it is heavier and sinks. A light fuel, which has a low specific gravity, has a higher API
gravity than a heavy fuel.
Specific gravity of water at 4o
C = 1.000
Specific gravity of water at 15.5o
C (60 o
F) = 1.001
UNITS OF API GRAVITY
Although mathematically, API gravity has no units, it is nevertheless referred to as being
in ‘degrees API’ o
API
OTHER SYSTMES USED FOR CORELATIONS
Many other specialized systems of measuring density and specific gravity such as degree
Baume (o
Be) and degree Twaddle (o
Tw) exist. On Baume scale at 20oC (68oF), the
relationship between specific gravity and degree Baume is given as


o
Be = - 130 (for liquids lighter than water)
o
Be = 145 - (for liquids heavier than water)
An older version of the scale for liquids heavier than water, at a reference temperature of
15.5o
C (59.9 o
F), uses 144.32 rather than 145.
APPLICATIONS OF SPECIFIC GRAVITY
• Specific gravity determines the maximum power per unit of weight/volume.
Hydrocarbons of low specific gravity (paraffins) possess the maximum thermal energy
per unit volume. Hydrocarbons of high specific gravity (aromatics) possess the
maximum thermal energy per unit weight. However, high calorific value of normal
paraffins cannot be fully utilized because of their low anti-knock ratings.
• Aromatics produce more carbon deposits than paraffins. These considerations together
favor the use of iso-paraffins for aviation gasoline. The lighter the crude oil (the higher
o
API), the larger is the content of the lighter constituents like gasoline and kerosene.
Aromatics have higher specific gravity than paraffins.
• It provides an indication to find the heating value of fuel.
• It is used to suggest whether hydrogen and carbon contents are higher or lower.
• Higher specific gravity means higher carbon to hydrogen ratio. Hence, heavier oils
have lower gross calorific value on weight basis but higher gross C.V. on volume
basis.
• Aromatics have higher specific gravity than paraffins. Hence, knowledge of specific
gravity can predict the quality of a product.
• Increase in specific gravity means decrease in paraffin contents. An increase in
specific gravity increases the amount of heat per unit volume.
How API gravity or the specific gravity is measured
Hydrometer is used for the determination of specific gravity up to 0.001.
For higher values, specific gravity bottle is used. For a semi-solid mass like tar, an indirect
method is used. Tar is mixed with equal volume of kerosene to make a thick solution.
Specific gravity of tar is given by


T= 2 M – K
Where,
T = Specific Gravity of Tar
M = Specific Gravity of mixture of tar and kerosene
K = Specific Gravity of Kerosene.
When we use the hydrometer to measure API or specific gravity we immerse hydrometer
in the fuel and observe the depth to which it sinks. For an accurate determination, a
correction must be made for the change in density of the liquid at the temperature of the
reading from the density at (15.5o
C) 60o
F due to thermal expansion. Tables are available
for finding the amount of this correction, or the following formula can be used (with high
accuracy between 30 to 90 degree API), for converting degrees API at some observed
temperature degree API at 60 o
F
Deg API at 60 F = [0.002(60 – observed temp F) + 1] *[observed deg API]†
† S . R. Beitler and E. J. Lindahl. ‘Hydraulic Machinery’, The Ronald Press Company,
New York, 1947
The density of a fuel, being directly depended upon the hydrogen and carbon content of
the liquid, is also related to the heating value of the fuel. The relationship between the API
gravity of a fuel and the heating value appears in the following;


Figure A: Density-G.C.V Relationship of Petroleum Liquids
(Courtesy of Combustion Engineering – Superheater, Inc.)
Specific gravity can be used to find the gross calorific value of petroleum products using
following formula of U.S Bureau of Mines
G.C.V = 12400 - 2100 2
Where = Specific gravity of oil at 15.5o
C
G.C.V = Gross Calorific Value (Kcal/Kg or Kcal/liter)


Typical specific gravity of crude and its products are given below;
Crude 0.78 – 0.96
Gasoline 0.7 – 0.76
Diesel 0.82 – 0.86
Lube Oil < 0.9
Reduced Crude 0.92 – 0.96
DENSITY OF PETROLEUM PRODUCTS VERSUS TEMPERATURE
There are figures which provide us with approximate relationship of density with
temperature. It can be used to convert density of fuel oil or any other Petroleum product at
15o
C to density at any other desired test temperature, to
C


Figure B: Temperature- Density Relationship for Petroleum Products
Courtesy from Elements of Fuels, Furnaces and Refractories, O.P. Gupta


Figure C: Specific Gravity Vs Calorific Value of Fuel Oils
Courtesy from Elements of Fuels, Furnaces and Refractories, O.P.Gupta
How to use above figure:
In order to determine the density of fuel oil (having density 0.95 at 15o
C) at any desired
temperature say 40o
C, draw a vertical line at 40o
C to the point where it meets 0.95
Density- Temperature line. From the point of intersection, draw a horizontal line. This
line, meets the Density temperature line at 0.935. So the density of the fuel oil at 40o
C is
0.935. The inverse approximation can be made similarly.


Experimental Work
OBJECTIVE
• To determine the specific gravity of given sample of oil using specific gravity bottle
method at room temperature.
• Report the API and density of sample at room temperature
• Calculate the approximate value of Gross Calorific and specific gravity 60/60 from the
figure A or C
• Report the difference of experimental and observed specific gravity 60/60, API and
G.C.V.
APPARATUS
Specific Gravity Bottle, Beaker, Weight Balance
PROCEDURE
• Clean and dry the specific bottle and weigh it (including stopper) when empty.
• Fill the bottle with water to the top and place the stopper, by doing so the excess water
will escape from the capillary of the stopper.
• Thoroughly wipe and clean the bottle outside and carefully weigh it.
• Do the same procedure by filling the bottle with different samples of oils and observe
the temperature of oils immediately and apply density correction for temperature and
calculate the API using formula.
• At calculated API, report the specific gravity, and Gross Calorific Value from the chart
provided.
OBSERVATION AND CALCULATIONS
Room Temperature T1 = _____________o
C
Weight of empty specific gravity bottle = M1= ___________g
Weight of specific gravity bottle + water = M2= ____________g
Weight of water = M3 = M2 – M1= _________________g


Weight of bottle + oil sample = M4 = ________________g
Weight of oil sample = M5 = M4 – M1 = ________________g
As we know that
a) Specific gravity of oil at room temperature
Specific Gravity = (wt of oil)/ (wt of water)
= (M5/M3)
= ____________________ atT1/T1
Density of water at T1 = d1= ___________________ g/cm3
Density of water at 60 F = d2 = _________________ g/cm3
Density of Oil at T1 = d1= ___________________ g/cm3
Density of Oil at 60 F = d3 = _________________ g/cm3
Specific Gravity (60/60) = d3/d2
For API Gravity (Experimental):
o
API = - 131.5
Experimental Values of G.CV
G.C.V = 12400 -2100(d2
) (Kcal/Kg) or
G.C.V = 22320 – 3780 d2
(Btu/lb)
d = specific gravity at 60F
Observed values of G.C.V and API (From figure A /C) =
Difference of experimental and observed specific gravity 60/60= ____________
Difference of experimental and observed API = ____________
Difference of experimental and observed G.C.V = ____________


PETROLANALYSIS (FLASH POINT)
Theory
FLASH POINT
It is the minimum temperature at which oil gives out sufficient vapors to form an in-
flammable mixture with air and catches fire momentarily when flame is applied. Generally
it should be above 150° F (65.5 °C). For products less than 150 °F required special
regulations exit regarding safety in storage and handling.
PRINCIPLE OF OPERATION
Flash points are determined by a particular vapor/air concentration above the surface of
the liquid hydrocarbons. When a critical is reach flashing occurs applying a test flame.
The flash point of a liquid hydrocarbon is influenced largely by the lighter, more volatile
components since these are more easily vaporized.
In the flasher continuous flash point analyzer a test flame, as specified for the standard
laboratory test, is not use to detect the flash point. Instead a platinum / palladium catalyst
is use to detect the critical hydrocarbon vapor concentration that corresponds with the
flash point. This particular vapor/air mixture reacts on the catalyst surface produce a
reproducible catalyst temperature. It is the difference b/w this temperature and the
temperatures caused by the concentration other than the critical (flash point) concentration
that is use to control the heat applied to the fresh sample feed before it mixed with air. If
the vapor/air mixture flowing over the catalytic detector is blow flash point concentration,
then the detector temperature falls. This is sensed, compared with the “set point”
temperature for the flash point concentration and the error is used to increase the heat to
liquid feed as the temperature increases more vaporization occurs, until the flash point
concentration is reached and the detector is again at the “set point” temperature. The
reverse occurs when the vapor/air mixture is above flash point concentration, and the
heating of the liquid is reduced.
FIRE POINT
It is the lowest temperature at which vapor given off by oil ignites and continues to burn
for at least 5 seconds. In most cases fire point if 5 ~ 40 °C higher than flash point and


determined the same manner as flash point is. It gives an idea of fire hazards during the
storage and use of oil.
FLAMMABLE LIMITS
Flammable limits are defined as the upper and the lower concentration of fuel vapors in air
that will burn a suitable ignition source is introduced. If the fuel concentration is either too
rich (the ratio of fuel to oxygen is too high) or to lean (the ratio of fuel oxygen is too low)
burning will not continue with the ignition source is removed.
FLAMMABILITY CHARACTERISTICS OF SOME SELECTED
ORGANIC SOLVENT
Flammable Limits
SOLVENT BOILING
POINT
(°C)
LOWER UPER AUTOIGNITION
TEMP (°C)
SOLVENT
ACCETONE 56 2.6 12.8 465 -20.0
BENZEN 80 1.3 7.1 498 -11.0
CYCLOHEXENE 81 1.3 8.0 245 -20.0
DYETHYLETHER 35 1.9 36.0 160 -45.0
ETHANOL 79 3.3 19.0 363 13.0
HEXANE 68 1.1 7.5 223 -22.0
ISOBPROPANOL 82 2.0 12.0 399 12.0
TOLUENE 111 1.2 7.1 480 4
(NOTE: The flammable limits are measured as percent by volume in air.)


IGNITION TEMPERATURE
Auto ignition temperature is the minimum temperature at which a solvent will ignite when
the liquid is dropped on the surface of a hot plate (with no other ignition source present).
In contrast, the lowest temperature at which a vapor-air mixture above a liquid will ignite
when a suitable ignition source (such as a flame or spark is introduced) is the flash point.
Both of the above mentioned ignitions temperatures will vary with exact method by which
they are measured and, therefore, any reported value must be considered as approximate.
Some of the characteristics of common solvent below;
TYPE OF INFORMATIONS GIVEN BY FLASH POINT
It gives us the idea about,
• Nature of the BP diagram of the system.
• Volatility of liquids fuels.
• Explosion hazardous
• Amount of low boiling fraction present in the liquid fuels.
APPARATUS USED TO DETERMINE FLASH POINT:
PENSKEY’S MARTEN closed cup apparatus is used to determine flash point or oils > 50
°C Cleveland cup apparatus for < 50 °C oils. Abel closed cup is used for kerosene.
DIFFERENCE B/E OPEN CUP AND CLOSED CUP
In “closed cup” the oil is heated in the close vessel until the temperature is reached at
which vapor in the air space one sufficient to form an inflammable mixed and so ignite
when flame is applied.
In “open cup” apparatus the cup has no cover and the air above the liquid is in free
content with surrounding atmosphere.
TYPICAL APPLICATIONS
1. The monitoring of crude distillation side stream strippers.
2. Heating oil blending.


Experimental Work
OBJECTIVE
To determine the flash point of the given sample of petroleum fraction using PENSKY
MARTEN closed cup apparatus. Compare the results with theoretical values (from
literature) of petroleum fractions being used.
APPARATUS
Thermometer, beakers, sample of petroleum friction and PENSKY Marten closed cup
apparatus.
PROCEDURE
• The oil cup is cleaned and dried (care being taken that no traces of any low flash
solvent used in cleaning remain in the cup of apparatus).
• The sample oil is then passes into the cup upto the level indicated by the filling mark.


• Place the lid over cup in its position and insert a thermometer in the holder.
• The apparatus is heated at the rate of from 9 – 11 °F per minute and the stirrer is
rotated at rate from 1 -2 revolution per second.
• Apply the test flame at a temperature intervals of 2 °F (up to 220 °F ) or at intervals of
5 °F (above220 °F)in such a manner that the flame is lowered in one half second, left
in its lowered position for one seconds and quickly raised (while the test flame is being
applied, stirring is stopped)
• When the flash point is nearly reached a blue halo (circle of light) is often formed or
observed round the test flame (this is not the actual flash).
• The temperature at which a distinct flash is visible in the two observation flash points,
this reading of temperature is recorded as flash point of sample under observation.
Serial
Number
Sample of Petroleum Fraction Flash Point °F Flash Point °C
REULTS
1. The flash point of sample no 1 = .°F or °C
2. The flash point of sample no 2 = . °F or °C
3. The flash point of sample no x = . °F or °C
4. Also compare the results with theoretical values (from literature) of different
Afractions of petroleum like kerosene, Gas oil or Diesel oil.
DISCUSSION ON RESULTS


CLOUD POINT AND POUR POINT
Theory
CLOUD POINT
When oil is cooled at a specific rate, the temperature at which it becomes cloudy or hazy is
called the cloud point of oil. The haziness us due to the separation of crystals of wax or
increase of viscosity at low temperature.
Cloud point is important for fuel oils which have to pass through unheated filters or fine
mesh e.g., a jet plane may be exposed to -60o
C and if solid wax separates from fuel oil the
carburetor may be blocked up.
POUR POINT
The temperature at which the oil just ceases to flow (or pour) is called the pour point. It
determines the temperature below which, oil cannot be used as a lubricant.
Naphthenes and aromatics have lower pour point than paraffins but they are undesirable in
fuel oils and diesel fuels. Asphalts act as pour point depressants as they inhibit the growth
of wax crystals. Increasing lighter hydrocarbons reduce pour point.
POUR POINT DEPRESSANTS
The pour point is the lowest temperature at which a lubricant will flow. In order to obtain
flow of oil at low temperature (fluidity), pour depressants are added to the lubricating oil
to lower the pour point. These additives tend to inhibit the formation of wax at the low
temperatures. In many formulations, especially those containing viscosity improvers,
supplemental pour depressants are not needed since other additives also have pour point
depressant properties.
Typical applications include diesel and gasoline engine oils, transmission fluids, tractor
fluids, hydraulics fluids, and circulation fluids.
APLLICATIONS OF CLOUD AND POUR POINTS
Cloud and pour point indicates the suitability if lubricants in cold condition are used.
Lubricants used in a machine working at low temperatures should possess low pour points;


otherwise solidification of lubricants will cause jamming of the machine. Presence of
waxes in the lubricating oil raises the pour point.
The difference of pour point and cloud point is 4 ~ 6 o
F.
FREEZING POINT
It is the temperature at which the fuel oil freezes completely and cannot flow at all. This is
important in case of aviation gasoline because at high altitudes where low temperatures are
encountered, fuel supply from fuel tank to engine may be impeded due to chocking of
pipeline if the freezing point of the fuel oil is not sufficiently low. Paraffins possess higher
freezing points than Naphthenes and aromatics. Aviation gasoline should have freezing
point below 60oC to avoid trouble due to crystal formation in feed lines and filters.
APPARATUS DESCRIPTION
The apparatus is in simplicity itself, consisting of a cylindrical test jar with flat bottom.
The assist even cooling the test jar is jacketed with a wider tube. A disc of cork or felt iis
placed between the bottom of the test jar and the jacket and a distance ring of cork of felt
keeps the jar in test position. The thermometer is inserted through a cork into the test jar so
that the bulb rests on the bottom. This assembly is suitably supported in a cooling bath of
optional size.


Experimental Work
OBJECTIVE
To determine the cloud point and pour point of the given sample of oil.
APPARATUS
FOR CLOUD POINT
• The oil is dried by passage through filter paper until perfectly clear at a
temperature least above the cloud point.
• Into the test jar is poured the oil to a depth 51 – 57 mm.
• It is important that the inside of the jacket shall be clean and dry. The next
important factor is the cooling.
• First the assembly is inserted into a cooling medium at 30 - 35°F. so that only
about one inch of the jacket projects above the liquid medium.
• As the cooling precede the test jar is withdrawn quickly, but without disturbing the
oil, for every 2°F fall and examined for cloud, and replaced within 3 seconds.
• If no cloud appears when it reaches 50°F it is transferred to a second cooling bath
at 0 - 5°F and examined as before
• Should there be sign of cloud at 20°F it is transferred to a third cooling bath at -
30°F to -25°F.
• The first distinct cloudiness or haze in the oil at the bottom of the test jar is
regarded as the cloud point.
FOR POUR POINT
• For pour point determination proceeds as for cloud point, but before cooling, the
oil shall be heated without stirring to 115°F in bath at 118°F, and then cooled in air
to 90°F. If the pour point of the oil is below -30°F.
• Cooling is as before, but instead of withdrawing the test jar at every 2°F it is
withdraw at every 5°F.
• When the jar is tilted to ascertain whether the oil is still fluid.
• As soon as the oil ceases to flow the jar is held in a horizontal position for exactly
5 seconds.


• If the oil shows any movement under these conditions the test jar is held on a
horizontal position for exactly 5 seconds.
• The pour point is taken as the temperature 5°Fabove the temperature at which it
just ceases to flow.
RESULTS
Cloud point of given sample is .
Pour point of given sample is .

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