Energy engineering-lab-manual zaman-1 a

Department of Chemical Engineering, Energy Engineering (Lab Manual) Wah Engineering College, University of Wah, Wah Cantt

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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




COAL ANALYSIS 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 0oC 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 (25oC) 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 (25oC) 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.



UPB

DC

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.




a) Determine the Kinematic Viscosity of the given sample of lubricating oil at room

temperature 35oC, 45oC, 55oC, 65oC 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 oE.

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 35oC, 45oC, 55oC, and 65oC 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 oE> 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 oE.

Sr. No. Experimental Degree

Engler oE (A)

Observed Degree

Engler oE (B)

A-B / B-A



e) Graph:

Kin

emat

ic v

isco

sity

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, 25oC, 30oC, 35oC and 40oC 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



DIESEL ANALYSIS (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

2ndStroke (Compression)

The piston compresses the mixture.

3rdStroke (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.

4thStroke (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

95oC and for hexyl benzene is -12oC.



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.


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 60oF.

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

oAPI = - 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 4oC = 1.000

Specific gravity of water at 15.5oC (60 oF) = 1.001

UNITS OF API GRAVITY

Although mathematically, API gravity has no units, it is nevertheless referred to as being

in ‘degrees API’ oAPI

OTHER SYSTMES USED FOR CORELATIONS

Many other specialized systems of measuring density and specific gravity such as degree

Baume (oBe) and degree Twaddle (oTw) exist. On Baume scale at 20oC (68oF), the

relationship between specific gravity and degree Baume is given as



oBe = - 130 (for liquids lighter than water)

oBe = 145 - (for liquids heavier than water)

An older version of the scale for liquids heavier than water, at a reference temperature of

15.5oC (59.9 oF), 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 oAPI), 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 (15.5oC) 60oF 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 oF

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 15.5oC

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

15oC to density at any other desired test temperature, toC



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 15oC) at any desired

temperature say 40oC, draw a vertical line at 40oC 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 40oC is

0.935. The inverse approximation can be made similarly.




• 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 = _____________oC

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):

oAPI = - 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 = ____________



PETROL ANALYSIS (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.




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 -60oC 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.




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 .