Properties of Aluminium

Aluminium has a unique and unbeatable combination of properties that make it into a versatile, highly usable and attractive construction material.

Weight
Aluminium is light with a density one third that of steel, 2.700 kg/m3.

Strength
Aluminium is strong with a tensile strength of 70 to 700 MPa depending on the alloy and manufacturing process. Extrusions of the right alloy and design are as strong as structural steel.

Elasticity
The Young’s modulus for aluminium is a third that of steel (E = 70,000 MPa). This means that the moment of inertia has to be three times as great for an aluminium extrusion to achieve the same deflection as a steel profile.

Formability
Aluminium has a good formability, a characteristic that is used to the full in extruding. Aluminium can also be cast, drawn and milled.

Machining
Aluminium is very easy to machine. Ordinary machining equipment can be used such as saws and drills. Aluminium is also suitable for forming in both the hot and the cold condition.

Joining
Aluminium can be joined using all the normal methods available such as welding, soldering, adhesive bonding and riveting.

Corrosion resistance
A thin layer of oxide is formed in contact with air, which provides very good protection against corrosion even in corrosive environments. This layer can be further strengthened by surface treatments such as anodising or powder coating.

Conductivity
The thermal and electrical conductivities are very good even when compared with copper. Furthermore, an aluminium conductor has only half the weight of an equivalent copper conductor.

Linear expansion
Aluminium has a relatively high coefficient of linear expansion compared to other metals. This should be taken into account at the design stage to compensate for differences in expansion.

Non-toxic
Aluminium is not poisonous and is therefore highly suitable for the preparation and storage of food.

Reflectivity
Aluminium is a good reflector of both light and heat.

Ductility

Aluminium is ductile and has a low melting point and density. In a molten condition it can be processed in a number of ways. Its ductility allows products of aluminium to be basically formed close to the end of the product’s design.

Impermeable and Odourless

Aluminium foil, even when it is rolled to only 0.007 mm thickness, is still completely impermeable and lets neither light aroma nor taste substances out. Moreover, the metal itself is non-toxic and releases no aroma or taste substances which makes it ideal for packaging sensitive products such as food or pharmaceuticals.

Cement & Properties

What is concrete?

Concrete is not found in nature the way we would find aluminium, nickel or iron. Concrete is formed from combining water, a special cement and rock: PORTLAND CEMENT + H2O + ROCK = HARDENED CONCRETE + ENERGY(HEAT)
A common mistake people make is to use the words cement and concrete interchangably. It is important to remember that cement is only a component of concrete and concrete is the structural material. The cement used in concrete is not used as a building material because it would be too expensive and not as strong as concrete. So when you see a parking garage, a driveway, a sidewalk or a road remember it is made of concrete, not cement. And, by the way, that funny looking truck is a concrete mixer, not a cement mixer! But, if cement is not concrete, then what is it?
Cement is a general name for a material that binds other materials together. Yes, it is another name for glue. There are many materials which we would classify as cements and they are usually identified with certain uses, and can produce different types of "concrete". The type of cement used to make the riding surface of some of our roads (blacktop!) is called asphalt cement. It is a petroleum bi-product, and it binds rock into the road material we call asphaltic concrete.
Adding water to the dry cement starts a chemical reaction (hydration). While the mixture of cement, water, and rock is fluid, it can be poured into molds (called formwork) of arbitrary shape. This is a valuable property of concrete which allows us to build dams with the many different shapes which you saw in the history of dams. The compound gradually hardens into the desired final shape. The water/cement ratio (w/c) of the mixture has the most control over the final properties of the concrete. The water/cement ratio is the relative weight of the water to the cement in the mixture. The water/cement ratio is a design criterion for the engineer. Selection of a w/c ratio gives the engineer control over two opposing, yet desirable properties: strength and workability. A mixture with a high w/c will be more workable than a mixture with a low w/c: it will flow easier. But the less workable the mixture, the stronger the concrete will be. The engineer must decide what ratio will give the best result for the given situation. This is not an entirely free choice because the water/cement ratio needs to be about 0.25 to complete the hydration reaction. Typical values of w/c are between 0.35 and 0.40 because they give a good amount of workability without sacrificing a lot of strength.
	The other important component for strength is the aggregate, the rock that is being bound by the hardened cement. Aggregate is what makes the difference between hardened cement and the structual material, concrete. Aggregate increases the strength of concrete and is a fundamental economical factor because it takes up a large volume of the concrete and is much less expensive than an equivlant volume of cement. To make very strong concrete requires a low w/c and strong aggregate. There might be thousands or millions of tons of cement and aggregate in a large dam. Finding the aggregate for the dam, and transporting it and the cement to the dam site are important societal factors.

Properties of concrete

Concrete has relatively high compressive strength, but significantly lower tensile strength, and as such is usually reinforced with materials that are strong in tension (often steel). The elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix cracking develops. Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep.

Tests can be made to ensure the properties of concrete correspond to specifications for the application.The density of concrete varies, but is around 2,400 kg/m³ (150 pounds per cubic foot or 4,050 lb/yd³).lol= 0870312642}}</ref> As a result, without compensating, concrete would almost always fail from tensile stresses – even when loaded in compression. The practical implication of this is that concrete elements subjected to tensile stresses must be reinforced with materials that are strong in tension.

Reinforced concrete is the most common form of concrete. The reinforcement is often steel, rebar (mesh, spiral, bars and other forms). Structural fibers of various materials are available.

Concrete can also be prestressed (reducing tensile stress) using internal steel cables (tendons), allowing for beams or slabs with a longer span than is practical with reinforced concrete alone. Inspection of concrete structures can be non-destructive if carried out with equipment such as a Schmidt hammer, which is used to estimate concrete strength.The ultimate strength of concrete is influenced by the water-cementitious ratio (w/cm), the design constituents, and the mixing, placement and curing methods employed. All things being equal, concrete with a lower water-cement (cementitious) ratio makes a stronger concrete than that with a higher ratio. The total quantity of cementitious materials (portland cement, slag cement, pozzolans) can affect strength, water demand, shrinkage, abrasion resistance and density. All concrete will crack independent of whether or not it has sufficient compressive strength. In fact, high Portland cement content mixtures can actually crack more readily due to increased hydration rate. As concrete transforms from its plastic state, hydrating to a solid, the material undergoes shrinkage. Plastic shrinkage cracks can occur soon after placement but if the evaporation rate is high they often can actually occur during finishing operations, for example in hot weather or a breezy day. In very high-strength concrete mixtures (greater than 70 MPa) the crushing strength of the aggregate can be a limiting factor to the ultimate compressive strength. In lean concretes (with a high water-cement ratio) the crushing strength of the aggregates is not so significant.

The internal forces in common shapes of structure, such as arches, vaults, columns and walls are predominantly compressive forces, with floors and pavements subjected to tensile forces. Compressive strength is widely used for specification requirement and quality control of concrete. The engineer knows his target tensile (flexural) requirements and will express these in terms of compressive strength.Wired.com reported on April 13, 2007 that a team from the University of Tehran, competing in a contest sponsored by the American Concrete Institute, demonstrated several blocks of concretes with abnormally high compressive strengths between 340 and 410 MPa (49,000 and 59,000 psi) at 28 days. The blocks appeared to use an aggregate of steel fibres and quartz – a mineral with a compressive strength of 1100 MPa, much higher than typical high-strength aggregates such as granite (100–140 MPa or 15,000–20,000 psi).

Reactive Powder Concrete, also known as Ultra-High Performance Concrete, can be even stronger, with strengths of up to 800 MPa (116,000 PSI). These are made by eliminating large aggregate completely, carefully controlling the size of the fine aggregates to ensure the best possible packing, and incorporating steel fibers (sometimes produced by grinding steel wool) into the matrix. Reactive Powder Concretes may also make use of silica fume as a fine aggregate. Commercial Reactive Powder Concretes are available in the 170–210 MPa (25,000–30,000 psi) strength range.

Gear

Gears are the most common means of transmitting power in mechanical engineering. There are tiny gears for devices like wrist watches and there are large gears that some of you might have noticed in the movie Titanic. Gears form vital elements of mechanisms in many machines such as vehicles, metal tooling machine tools, rolling mills, hoisting and transmitting machinery, marine engines, and the like. Toothed gears are used to change the speed, power, and direction between an input and output shaft. This site is all about Gears. Visit the pages linked below to know more about different types of gears:

Bevel Gear Reducer	Hypoid Gears
Bevel Gearbox	Gear Pump
Bicycle Gears	Gearbox
Fixed Gear Bicycle	Speed Reducers
Gear Coupling	Differential Gear System
Gear Cutting	Worm Gear Reducer
Gear Manufacturing	Worm Gear Speed Reducer
Gear Technology	Spur Gear
Helical Gears	Bevel Gears
Worm Gears	Gear Design
Gear Manufacturer	Gear Lube
Gear Ratio	Gear Wrench
Hydraulic Gear Pump	Planetary Gear
Gear Reducers	Plastic Worm Gears
Worm Gear Drives	Worm Gear Speed Reducers
Spider Gears	Gear Oil

Construction and Working of a Bevel Gear Reducer

One of the major applications of gears is gear reduction. The high power and low torque of the supply can be converted into high torque by coupling of a smaller input gear with a larger gear. There are different types of gear reducers depending on the types of gears coupled viz. worm gear reducer, spur gear reducer, bevel gear reducer etc.

Construction of a Bevel Gear Reducer
A bevel gear reducer consists of a small gear acting as a pinion coupled with another gear of a larger diameter at right angles to each other. The gears can be either of spur or helical type. Helical gears are preferred as they are less noisy due to gradual engagement. The material can be either plastic or metal depending on the application. Three gears can be used in case we need to keep the axis of rotation the same as that of input. The whole arrangement is sealed in a metal or plastic casing known as housing. The point of contact is lubricated with gear oil.

Working of a Bevel Gear Reducer
The diameter of the output being larger than that of the input gear, the torque of the system is increased at the expense of speed. Since the speed is decreased, this system is known as a reducer. The gears are at right angles to each other and hence the direction of the rotary motion is changed.

Advantages of a Bevel Gear Reducer
The efficiency of a bevel gear reducer is higher than that of a typical worm gear reducer. The bevel gears have high load capacity.

Applications of a Bevel Gear Reducer
Due to change in direction of the rotary motion the bevel gear reducer finds a variety of applications in industry and automotives. In industries it is used in turbines, pumps, cranks, etc. In automotives it is used in ordinary as well as limited slip differentials.

Hypoid Gears Are a Subtype of Bevel Gears

Gears are major part of any machine working on the principle of rotary motion. The motion can be produced either by a motor or engine and is called the input. The engine usually has a very high angular momentum but the torque is small. This torque is not enough for performing work under heavy load and hence cannot be used directly in industrial machines. To overcome this problem, coupled gears are used.

In coupled gear system, the input is connected through a driving shaft to a small gear called the pinion. The pinion is further coupled with a gear of larger diameter i.e. high gear ratio. Due to this form of coupling, the torque of the engine increases at the expense of angular momentum. A variety of gears can be used for this purpose viz. spur gears, helical gears, worm gears, etc.

However these gears have a limitation i.e. they can only be used in systems where the input and output shafts are in the same plane. To overcome this problem, a special type of gear called the hypoid gear is used.

The hypoid gears are a subtype of bevel gears. On observation the hypoid gear seems to be similar in appearance to the helical bevel gears. The main difference being that the planes of the input and the output gears are different. This allows for more efficient intermeshing of the pinion and driven gear. Since the contact of the teeth is gradual, the hypoid gear is silent in operation as compared to the spur gears.

These gears are usually used in industrial and automotive application and hence the material used is a metal like stainless steel. A major application of hypoid gears is in car differentials where the axes of engine and crown wheel are in different planes.

science

Science (from Latin: scientia meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. An older and closely related meaning still in use today is that of Aristotle, for whom scientific knowledge was a body of reliable knowledge that can be logically and rationally explained (see "History and etymology" section below).

Since classical antiquity science as a type of knowledge was closely linked to philosophy. In the early modern era the two words, "science" and "philosophy", were sometimes used interchangeably in the English language. By the 17th century, "natural philosophy" (which is today called "natural science") had begun to be considered separately from "philosophy" in general.However, "science" continued to be used in a broad sense denoting reliable knowledge about a topic, in the same way it is still used in modern terms such as library science or political science.

In modern use, science is "often treated as synonymous with ‘natural and physical science’, and thus restricted to those branches of study that relate to the phenomena of the material universe and their laws, sometimes with implied exclusion of pure mathematics. This is now the dominant sense in ordinary use.This narrower sense of "science" developed as a part of science became a distinct enterprise of defining "laws of nature", based on early examples such as Kepler's laws, Galileo's laws, and Newton's laws of motion. In this period it became more common to refer to natural philosophy as "natural science". Over the course of the 19th century, the word "science" became increasingly associated with the disciplined study of the natural world including physics, chemistry, geology and biology. This sometimes left the study of human thought and society in a linguistic limbo, which was resolved by classifying these areas of academic study as social science. Similarly, several other major areas of disciplined study and knowledge exist today under the general rubric of "science", such as formal science and applied science.

Lab

PETROLEUM TESTING LABORATORY

DEPARTMENT OF CHEMICAL ENGINEERING

M.TECH. PETROLEUM REFINING AND PETROCHEMICALS

CONTENTS
Sl.No.	Date	Name of the Experiment	Page No.
1		Flash and Fire point
2		Redwood Viscometer
3		Saybolt Viscometer
4		Engler Viscometer
5		Distillation Characteristics
6		API Gravity
7		Moisture content Determination
8		Softening Point
9		Smoke Point
10		Aniline Point
11		Cloud and Pour Point
12		Melting Point of Wax
13		Copper Strip Corrosion Test
14		Congealing Point of Wax

FLASH POINT AND FIRE POINT

BY PENSKY MARTENS APPARATUS

AIM

To determine the flash point and fire point of fuel oils by using Pensky Martens apparatus (closed type).

DEFINITION

FLASH POINT

The lowest temperature of the sample, corrected to a barometric pressure of 101.3 kPa 760 mm Hg , at which application of a test flame causes the vapour of the sample to ignite under specified conditions of test.

FIRE POINT

The fire point, is defined as the temperature at which the vapour continues to burn after being ignited.

SUMMARY OF METHOD

The sample is heated at a slow, constant rate with continual stirring. A small flame is directed into the cup at regular intervals with simultaneous interruption of stirring. The flash point is the lowest temperature at which application of the test flame causes the vapour above the sample to ignite.

SIGNIFICANCE

• Flash point measures the response of the sample to heat and flame under controlled laboratory conditions.
• It is only one of a number of properties which must be considered in assessing the overall flammability hazard of a material.
• Flash point is used in shipping and safety regulations to define ‘flammable’ and ‘combustible’ materials.

APPARATUS

• Pensky Martens Closed Tester
• Thermometers (Two standard thermometers shall be used with the Pensky-Martens tester)

TABULATION

S.No.	SAMPLES	FLASH POINT (ºC)	FIRE POINT(ºC)

PREPARATION OF SAMPLE

Samples of asphalts or very viscous materials may be warmed until they are reasonable fluid before they are tested. However, no sample should be heated more than is absolutely necessary. It shall never be heated above a temperature of 17°C ( 30°F ) below its expected flash point.

APPARATUS SPECIFICATIONS                       

A typical assembly of the apparatus, gas heated, is shown in Fig. The apparatus shall consist of a test cup, cover, and stove conforming to the following requirements.

Cup - The cup shall be of brass, or other non-rusting metal of equivalent heat conductivity, and shall conform to the dimensional requirements

Cover Proper - The cover shall be brass, and shall have a rim projecting downward almost to the flange of the cup. The rim shall fit the outside of the cup with a clearance not exceeding 0.36 mm 0.014 in on the diameter.

Shutter - The cover shall be equipped with a brass shutter approximately 2.4 mm ( 3/32 in ) thick operating on the plane of the upper surface of the cover. cover openings shall be exactly open and the tip of the exposure tube shall be fully depressed.

Flame Exposure Device - The flame-exposure device shall have a tip with an opening 0.69 to 0.79 mm (0.027 to 0.031 in) in diameter. This tip shall be made preferably of stainless steel, although it may be fabricated of other suitable metals

Pilot Flame - A pilot flame shall be provided for automatic relighting of the exposure flame.

Stirring Device - The cover shall be equipped with a stirring device mounted in the centre of the cover and carrying two 2-bladed metal propellers.

Stove

Heat shall be supplied to the cup by means of a properly designed stove which is equivalent to an air bath. The stove shall consist of an air-bath and a top plate on which the flange of the cup rests.

Air Bath

The air bath shall have a cylindrical interior and shall conform to the dimensional requirements in Fig. 

Top Plate

The top plate shall be of metal, and shall be mounted with an air gap between it and the air bath.

PROCEDURE

Ø  The oil cup was cleaned using solvent.

Ø  The cup was filled with fresh sample up to the mark.

Ø  The cup was placed in the apparatus bath.

Ø  The lid is placed on the cup and the thermometer was also inserted.

Ø  The electrical heater was turned to 50% of input volts and oil is heated.

Ø  After that spring handle was rotated at every degree rise from this point.

Ø  The temperature was noted at which the flash occurs.

Ø  The fire point was noted at which the fuel burnt continuously for 5 seconds.

Ø  The experiment was repeated for different samples.

RESULT

Flash point and fire point of given samples are ________________     is _______ oC

                     

Redwood viscometer

AIM

To determine the kinematic viscosity of the given sample of oil at various temperatures and to study corresponding variation with respect to temperature.

APPARATUS REQUIRED

·         Red wood viscometer with accessories

·         Measuring flask

·         Thermometer

·         Stop watch  

THEORY

·         Red wood viscometer is based on the principle of laminar flow through the capillary tube of standard dimension under falling head. The viscometer consists of vertical cylinder with an orifice at the center of the base of inner cylinder.

·         The cylinder is surrounded by a water bath, which can maintain temperature of the liquid to be tested at required temperature. The water bath is heated by electric heater.

·         Cylinder which is filled up to a fixed height with liquid whose viscosity is to be determined is heated by water bath to the desired temperature.

·         Then orifice is opened and the time required to pass the 50cc of oil is noted. With this arrangement variation of viscosity with temperature can be studied. 

FORMULA

·         In this case of red wood viscometer, the kinematic viscosity (v) of liquid and the time (t) required to pass 50cc of liquid are correlated by expression. 

                             ν =0.0026 – 1.175/t

Where,

·         ν = Kinematic viscosity

·         t =time in seconds to collect 50cc of oil.

OBSERVATION

Sl.No.	Temperature (0C)	Time taken to collect 50cc of oil (sec)	Kinematic viscosity (centistokes)

SIGNIFICANCE

·         Pump design can be done with the help of viscosity.

·         Pump operation of the engine depends on the proper viscosity of the liquid fuel.

·         It’s very important to know about the fluid flow through various objects.

·         Conveying of fluid can be done effect by means of viscosity data.

PROCEDURE

·         The instrument was leveled with the help of the circular bubble and by leveling foot screws.

The water bath was filled with water.

The orifice is closed with the ball valve and the cylinder is filled up to index mark with oil.

The steady state temperature of oil was recorded.

The procedure is repeated for different by heating oil with water bath.  

RESULT

The kinematic viscosity for the given sample was determined and the graph was plotted and it was observed that the kinematic viscosity of the given sample decreases with increases in temperature.

SAYBOLT VISCOMETER

                  

                                               

SAYBOLT VISCOMETER

AIM       

                To determine the viscosity of the given petroleum products and to study the variation of viscosity with respect to temperature.

APPARATUS REQUIRED

*        Saybolt viscometer apparatus

*        Thermometer (0 – 100 deg)

*        Sample

*        Stop watch

*        Beaker (100 ml capacity)

THEORY

            Viscometers are used to define the viscous properties of a fluid at ambient or defined temperatures. They are commonly available in the form of a calibrated capillary tube through which a liquid is allowed to pass at a controlled temperature in a specified time period. Other methods include rotational viscometry and falling ball tests. Viscometers can have a few different technologies by which they operate.

For rotational viscometry, torque is required to rotate a spindle at constant speed while immersed into the sample fluid.  The torque is proportional to the viscous drag on the immersed spindle, and thus to the viscosity of the fluid. For falling ball technology, the viscosity is proportional to the time required for a ball to fall through the test liquid contained in a precise an temperature controlled glass tube. Capillary viscometers measure the flow rate of a fixed volume of fluid through a small orifice at a controlled temperature.

The time it takes for a specific volume of fluid to pass through the orifice is proportional to the fluid viscosity. However, it also depends on the density of the fluid since the denser the fluid, the faster it will flow through the orifice. The property being measured is then the kinematic viscosity and not the dynamic viscosity.

TYPES OF VISCOMETERS

·         Reverse flow viscometers

·         Small volume viscometers

·         Viscometers

·         Vacuum viscometers

·         Cylinder viscometers

·         Hydra motion viscometers

OBSERVATION

S.No.	Temperature (0C)	Time (seconds)	Kinematic viscosity  (centistokes)

FORMULA

            Kinematic viscosity, ν = At-B/t

            Where, A=0.00226, B=1.95

            A and B are constants.

SAFETY PRECAUTIONS

·         Do not connect bath to a power supply unless the bath is filled with oil.

·         Do not leave unit unattended, especially when operating at high bath temperatures.

·         This could create a potential fire hazard.

SIGNIFICANCE

·         It is used to find the viscosity of the fluid.

·         Pump design can be done with the help of viscosity.

·         Pump operation of one engine depends on the proper viscosity of fuels.

·         Conveying of fluids can be done with the help of viscosity data.

·         It is very important to know about the fluid flow through various objects.

EXPERIMENTAL PROCEDURE

·         The viscometer was turned on after making sure that the bath was filled with oil.

·         The bath was heated by means of water heater.

·         The power switch was turned on. The bath temperature was maintained at various temperatures.

·         The bath was allowed to reach a steady temperature.

·         The cork stopper is used to block off the outlet of one of the Saybolt viscometer tubes.

·         A measured quantity (+60 ml) of the sample was poured into the tube.

·         The sample temperature was allowed to equilibrate with that of the bath (about 25 minutes).

·         Simultaneously the Saybolt tube was uncorked (using the pull chain) and the stopwatch was started.

·         When the oil has reached the 60 ml mark, the stopwatch was stopped. The time was recorded. The experiment was repeated for various temperatures.

RESULT

     Thus the kinematic viscosity for given sample was determined for different temperatures and tabulated. The graph was plotted and it was found that the kinematic viscosity decreases with increase in temperature.

ENGLER VISCOMETER

DETERMINATION OF KINEMATIC VISCOSITY BY ENGLER VISCOMETER

AIM

        To determine the kinematic viscosity of the given fluid using Engler viscometer.

APPARATUS REQUIRED

·         Engler viscometer

·         Timing device

·         Thermometer

·         Sample

THEORY

Specific viscosity of a substance in the Engler scale is the time required in seconds for the flow of 100cc of the sample divided by the time taken for the flow of equal volume of water. This viscometer allows direct comparison of viscosities of various samples without lead to calculate their actual viscosities.

Viscosity

            . Viscosity is the ratio between the shear stress and the velocity gradient. In other words, viscosity is the resistance offered by the fluid. The unit of viscosity is centipoises. In SI, kg/ms.

Newton’s law of viscosity

The shear stress is the product of absolute viscosity and velocity gradient.

τ = µ (dv/dx)

Kinematic viscosity

            It is defined as the ratio between the absolute viscosity and density, denoted by ν.

ν = µ / ρ

The unit of kinematic viscosity is centistokes.

Range of Engler viscometer

Temperature measurement range   0-100^oC

Viscosity range of fluids                 28.8 – 35.2 centistokes

OBSERVATION

S.No	TEMPERATURE          (OC )	TIME (sec)   SAMPLE        WATER                 t (sec)			KINEMATIC VISCOSITY (centistokes)

Significance

• In the determination of specific viscosity of tars and the fluid properties.
• In the determination of lubricating properties of fuel oils.

FORMULA

1)      ν = At – (B/t)

where ν = kinematic viscosity (centistokes)

            A, B = constants

            A = 0.076, B = 0.04

2)      t = (t₁-t₂)/60

where t = efflux time in seconds

            t₁ = time taken for collecting sample (sec)

            t₂ = time taken for collecting water (sec)

EXPERIMENTAL SETUP

It consists of a water bath having oil cup with lid. The water stirring device is mounted on a stand. Thermometer is dipped in water bath with help of clamp. The lid of the oil cup has a thermometer holder. The bath is fitted with water heater. It can be operated on 200 volt AC mains.

PROCEDURE

• The given sample was filled in the cup of the Engler viscometer up to the level marked.

• The lid was closed to prevent vaporisation of sample.
• The heater was switched on and the water temperature was noted.
• The water was stirred well to promote uniform heat distribution around the oil.
• When the temperature reaches specific value, heating was stopped and the stalk was removed.
• The time taken for flow of 100ml sample was noted.
• The orifice is closed again and the sample was refilled into the cup.
• The procedure was repeated for different temperatures and the readings were tabulated.
• The above procedure was also repeated by filling the cup with water.

RESULT

            The viscosity of the given sample was determined at various temperatures and graph was plotted. It is found that kinematic viscosity decreases with increase in temperature.

         

                                               

DISTILLATION CHARACTERISTICS

 SCOPE

            To determine the distillation characteristics (boiling range) of the given sample using the distillation apparatus.

     

Distillation

This method of test covers the distillation of motor gasoline, aviation gasoline, aviation turbine fuels, special boiling point spirits, naphtha, white spirit, kerosene, gas oils, distillate fuel oils and similar petroleum products. A 100 ml sample is distilled under prescribed conditions which are appropriate to its nature. Systematic observations of thermometer readings and volumes of condensate are made, and from the data, the results of the test are calculated and reported.

The distillation (volatility) characteristics of hydrocarbons have an important effect on their safety and performance, especially in the case of fuels and solvents. The boiling range gives information on the composition, the properties, and the behavior of the fuel during storage and use. Volatility is the major determinant of the tendency of a hydrocarbon mixture to produce potentially explosive vapors.

The distillation characteristics are critically important for both automotive and aviation gasoline, affecting starting, warm-up, and tendency to vapor lock at high operating temperature or at high altitude, or both. The presence of high boiling point components in these and other fuels can significantly affect the degree of formation of solid combustion deposits.

Distillation limits are often included in petroleum product specifications, in commercial contract agreements, process refinery/control applications, and for compliance to regulatory rules.

This test method can be applied to contaminated products or hydrocarbon mixtures. This is valuable for fast product quality screening, refining process monitoring, fuel adulteration control, or other purposes including use as a portable apparatus for field testing.

SIGNIFICANCE

v  Distillation (volatility) characteristics of petroleum products are indicative of performance in their intended applications.

v  Petroleum product specifications generally include distillation limits to ensure products of suitable volatility performance.

v  The empirical results obtained by use of this distillation method have been found to correlate with automotive equipment performance factors and with other characteristics of petroleum products related to volatility.

v  For motor spirit the 10% distillation value gives an indication of the engine start conditions, also the final boiling point.

OBSERVATION

             

S.No	Volume of Distillate collected (ml)	Temperature ºC

                                                      

Terminology

Initial Boiling Point

The thermometer reading which is observed at the instant that the first drop of condensate falls from the lower end of the condenser tube,

           

End-Point or Final Boiling Point

The maximum thermometer reading obtained during the test. This usually occurs after the evaporation of all liquid from the bottom of the flask. The term ‘maximum temperature’ is a frequently used synonym.

Dry Point

The thermometer reading observed at the instant the last drop of liquid evaporates from the lowest point in the flask. Any drops or film of liquid on the side of the flask or on the thermometer are disregarded.

Decomposition Point

The thermometer reading which coincides with the first indication of thermal decomposition of the liquid in the flask.

Percent Recovered

The volume in ml of condensate observed in the receiving graduate, in connection with a simultaneous thermometer reading.

Percent Recovery

The maximum percent that is recovered.

Percent Total Recovery

The combined percent recovery and residue in the flask.

Percent Loss

100 minus the percent total recovery.

Percent Residue

The percent total recovery minus the percent recovery, or the volume of residue in milliliters if measured directly.

Percent Evaporated

The sum of the percent recovered and the percent loss.

PROCEDURE

v  The given flask is to be thoroughly cleaned using solvent and dried.

v  The given test sample is then taken inside the flask and the cork with appropriate thermometer is placed on the neck of the flask.

v  The flask is placed on the asbestos board and fixed to the metal condensers with a cork. The asbestos board is raised of lowered till the flask is properly supported.

v  The 100cc measuring cylinder is placed below the condenser outlet. The heater is then switched on and the temperature variation is noted.

v  The temperature at which the first drop of distillate is collected in the measuring cylinder is noted and reported as the initial boiling point.

v  Heat is controlled, so that the distillation process is at a uniform state.

v  Middle boiling point is the temperature at which 50% of oil distills off.

RESULT

The Distillation characteristics are studied for the given samples and the values are noted as follows:

1.      Initial boiling point                                                         =                 º  C

2.      Middle boiling point                                                       =                 º  C

3.      Percentage of recovery                                                   =

4.      Percentage of non-volatile residue                                 =

5.      Film boiling point                                                           =                 º  C

                                                     

                                 

         API GRAVITY - DIAGRAM

                                                                     

DETERMINATION OF API GRAVITY OF CRUDE PETROLEUM AND LIQUID PETROLEUM PRODUCTS BY HYDROMETER METHOD AND SPECIFIC GRAVITY BOTTLE METHOD

AIM

            To determine the API gravity of crude petroleum and liquid petroleum products by hydrometer method and specific gravity bottle method.

THEORY

This method covers the laboratory determination, using a glass hydrometer, of the density, relative density, or API gravity of crude petroleum, petroleum products, or mixtures of petroleum and non-petroleum products normally handled as liquids and having a Reid vapour pressure of 1.8 bar (179 KPa) or less. The values are measured on a hydrometer at convenient temperatures, readings of density being reduced to 15 ^oC, and that of specific gravity and API gravity to 15.6 ^oC, by means of international standard tables.

CLASSIFICATIONS OR GRADES

Crude oil is classified as light, medium or heavy, according to its measured API gravity.

·         Light crude oil is defined as having API gravity higher than 31.1 °API.

·         Medium oil is defined as having API gravity between 22.3 °API and 31.1 °API.

·         Heavy oil is defined as having API gravity below 22.3 °API.

SIGNIFICANCE

Accurate determination of density, relative density, or API gravity of petroleum and its products is necessary for the conversion of measured volumes to volumes at standard temperature of 15°C.

FORMULA

API Gravity

A special function of specific gravity at 15.6/15.6 ^oC is represented by:

API gravity, degrees    = [141.5 /Specific gravity at 15.6/15.6 ^oC] - 131.5

APPARATUS REQUIRED

• Hydrometer
• Hydrometer cylinders
• Specific gravity bottle

OBSERVATIONS

Sl.No	SAMPLES	SPECIFIC GRAVITY
		At room temperature using Hydrometer	At room temperature using Specific gravity bottle method

SPECIFIC GRAVITY BOTTLE METHOD

Weight of the empty specific gravity bottle                                                   =

Weight of the specific gravity bottle with sample 1                                       =

Weight of the specific gravity bottle with sample 2                                       =

Weight of the specific gravity bottle with sample 3                                       =

Weight of the specific gravity bottle with sample 4                                       =

PROCEDURE

Hydrometer method

• The samples were transferred to hydrometer cylinders without any splashing to avoid air bubbles.
• The cylinders containing samples were placed in vertical position in a location free from air currents.
• The hydrometer was gently lowered into the sample in cylinders such that the hydrometer should not touch the walls of the cylinder.
• The hydrometer was allowed to float and when it comes to rest, the specific gravity indicated by the hydrometer for different samples at room temperature were noted.
• From the specific gravity values the API gravity for the given samples were calculated.

Specific gravity bottle method

• The samples were taken in each specific gravity bottle.
• The specific gravity bottle with the samples and the weight of the empty specific gravity bottle were measured.
• The readings were tabulated and the specific gravity for different samples was calculated. From the specific gravity values the API gravity for the given samples were calculated.

RESULT

The API gravity of the given samples using hydrometer and specific gravity bottles were calculated and tabulated as follows                                                                                      

Sl.No.	Samples	API gravity
		Hydrometer method	Specific gravity bottle method

                                                                     

 

DETERMINATION OF MOISTURE CONTENT BY DEAN AND STARK                                                  METHOD

SCOPE      

    To estimate the moisture content of the given liquid fuel using Dean and Stark Apparatus.

EXPERIMENTAL SETUP

The Dean-Stark apparatus or Dean-Stark receiver or distilling trap is a piece of laboratory glassware used in synthetic chemistry to collect water (or occasionally other liquid) from a reactor. It is used in combination with a reflux condenser and a batch reactor for continuous removal of the water that is produced during a chemical reaction performed at reflux temperature. It was invented by E. W. Dean and D. D. Stark in 1920 for determination of the water content in petroleum. The Dean-Stark trap (1920) changed the distillation procedure from a simple distillation to a multiple distillation by a change in design where by a refluxing condenser was introduced .This change resulted in a smaller boiling flask and required less distilling liquid. It renewed the interest in the distillation procedure, for it enabled the last traces of water.                                

DEAN AND STARK APPARATUS

Two types of Dean-Stark traps exist – one for use with solvents with a density less than water and one for use with solvents with a density greater than water.

The Dean-Stark apparatus in the laboratory typically consists of vertical cylindrical piece of glass (the trap, in figure), often with a volumetric graduation on its full length and a precision tap on the bottom very much like a burette. The top of the cylinder is  fit with the bottom of the reflux condenser. Protruding from the top the cylinder has a side-arm sloping toward the reaction flask. At the end the side-arm makes a sharp turn so that the end of the side arm  is vertical as well. This end connects with the reactor.

SIGNIFICANCE

v  This piece of equipment is usually used in azeotropic distillations. A common example is the removal of water generated during a reaction in boiling toluene.

v  The Dean-Stark method is commonly used to measure moisture content of items such as bread in the food industry.

v  This equipment can be used in cases other than simple removal of water. One example is the esterification of butanol with acetic acid catalyzed by sulfuric acid

v   The Dean and Stark procedure can be used to measure the water content of a diverse range of samples, and has been extensively used in industrial laboratories to measure water in petroleum oils.

PRINCIPLE

During the reaction in , vapors containing the reaction solvent and the component to be removed travel out of reaction flask up into the condenser ,and then drip into the distilling trap .Here, immiscible liquids separate into layers. When the top (less dense) layer reaches the level of the side-arm it can flow back to the reactor, while the bottom layer remains in the trap. The trap is at full capacity when the lower level reaches the level of the side-arm--beyond this point, the lower layer would start to flow back into the reactor as well. It is therefore important to syphon or drain the lower layer from the Dean-Stark apparatus as much as needed.

More rarely encountered is the model for solvents with a density greater than water. This type has a tube at the bottom of the side-arm to allow the organic solvent at the bottom to flow back into the reaction vessel. The water generated during the reaction floats on top of the organic phase. An azeotropic mixture of toluene and water distills out of the reaction, but only the toluene (density=0.865 g/ml) returns, since it floats on top of the water (density=0.998 g/cm³), which collects in the trap. This equipment can be used in cases other than simple removal of water. One example is the esterification of butanol with acetic acid catalyzed by sulfuric acid. The vapor contains 63% ester, 24% water and 8% alcohol at reflux temperature and the organic layer in the trap contains 86% ester, 11% alcohol and 3% water which is reintroduced. The water layer is 97% pure. Another example is the esterfication of benzoic acid and n-butanol where the ester product is trapped and the butanol, immiscible with the ester flows back into the reactor. Removing water in the course of these esterfications shifts the chemical equilibrium in favour of ester formation.

PROCEDURE

v  A known volume of the fuel sample is to be placed in a flask with equal volume of organic solvent such as xylene of toluene.

v  The organic solvent is chosen such that it is insoluble in water. It should have a higher boiling point than water and it should be safe to use.

v  The flask containing the sample with the organic solvent is then attached to a condenser by a side arm and the mixture is heated up.

v  The water in the sample gets evaporated and moves into the condenser where it is cooled and converted back into liquid water.

v  The water trickles into the graduated tube. The distillation is then stopped and the water present in the liquid fuel is measured.

RESULT

The amount of moisture content present in the sample was found using the Dean and Stark apparatus to be

SOFTENING POINT

  AIM

To determine the softening point of the given sample bitumen using ball and ring apparatus.

APPARATUS REQUIRED

Ø  Ring and ball apparatus

Ø  Steel balls

Ø  Brass rings

Ø  Thermometer

Ø  Stirrer

Ø  Water bath

SIGNIFICANCE

Ø  To find the consistency of bitumen

Ø  It is regarded by same indication of viscosity

Ø  It is used in the designation of hard as oxidized bitumen.

THEORY

Ø  The temperature at which the substance attains a particular degree of softness under specified condition of test is called softening point.

Ø  Bitumen is specified by softening point. Bitumen being amorphous does not melt sharply but gradually becomes softer and less viscous as the temperature rises.

Ø  For this reason, the determination of the softening point must be made by fixed arbitrary and closely defined method.

Ø  The softening point of bitumen is rounded out by the ball and ring test.

APPLICATION

Ø  Used in annealing of bitumen.

Ø  Processing of plastics.

Ø  Determining the quality of bitumen.

PROCEDURE

Ø  A beaker is taken and filled with ¾ of it with water.

Ø  The sample is placed in the ring and the steel ball is kept over the sample at the middle of the ring.

Ø  The whole ring and ball is immersed into the beaker which is filled with water.

Ø  The water in the beaker is heated by electrical coil.

Ø  A thermometer is inserted to note the temperature.

Ø  As the temperature increase, the sample gets softens and the steel ball over the sample gets immersed and finally drops out.

Ø  The temperature at which the ball falls down from the ring is noted as softening point of the sample.

Ø  The ring is washed and replaced with another sample and the process is repeated.

RESULT

Ø  The softening point of given first sample      =

Ø  The softening point of given second sample  =

                                         

FLAME HEIGHT

                                            

A-Too high

B- Correct

C-Too low

SMOKE POINT

AIM

This method is intended for the determination of smoke point of kerosene and other volatile liquid fuels including gas turbine (jet) fuels.

DEFINITION

The maximum flame height in millimetres at which kerosene or other volatile liquid fuels including gas turbine (jet) fuels will burn without smoking, when determined in the apparatus and under specified conditions.

OUTLINE OF THE METHOD

The sample is burned in a standard lamp in which it is possible to adjust the flame height against a background of a graduated millimetre scale. The smoke point is measured by raising the wick until a smoky flame is produced and then lowering to the point where the smoky tail just disappears. This flame height, measured to the nearest millimetres, is the smoke point of the sample

Requirements:

• Smoke point apparatus
• Fuel samples
• Wick

Smoke Point Lamp - Constructed according to the specification given. The lamp consists of an oil container provided with a wick tube and air vent, a gallery fitted with a wick guide and provided with air inlets, a lamp body, and a chimney provided with a 50-mm scale specified

Oil Container - This shall conform to the following dimensions (mm):

                                                                 

Body Oil Container:

Internal diameter                                21.25 ± 0.25

External diameter                               Sliding fit in holder

Length, without cap                           109-00 ± 0.05

Thread on cap                                     9’5 mm dia screwed 1.0 mm pitch

Wick Tube:

Internal diameter                               4’7 ± 0.05

External diameter                              Close fit in wick guide

Length                                                  82.00 ± 0.05

                   

OBSERVATION

S. No.	Sample(ml)	Smoke Point(mm)

       

Air Vent:

Internal diameter                               3.50 ± 0’05

Length                                                90.00 ± 0.05

Lamp - This shall conform to the following dimensions in mm:                                                                                   

Internal diameter of socket of oil container                23.80 ± 0.05

Internal diameter of wick guide                                  6.00 ± 0.02

Diameter of each of 20 air inlets                                 2.90 ± 0.05

x: External diameter of gallery                                    35.00 ± 0.05

Diameter of each of 20 air inlets in the gallery           3.50 ± 0.0.5

Internal diameter of lamp body                                   81.0 ± 1.0

Internal depth of lamp body                                        81.0 ± 1.0

Internal diameter of chimney                                      40.0 ± 1.0

Height, top of chimney to centre of lamp body         130.0 ± 1.0

Other Requirements - The lamp shall also comply with the following requirements:

a)The top of the wick guide shall be exactly level with the zero mark on the scale;

b) The scale shall be marked in white lines on black glass on each side of a white or black strip, 2mm in width. It shall have a range of 50 mm, graduated in one millimetre, figured at each 10mm, and with longer lines at each 5 mm;

c) A device for raising or lowering the flame shall also be provided.

The total distance of travel shall be not less than 10 mm, and the movement shall be smooth and regular. Further, with the oil container in the lowest position and the .wick projecting 6 mm above the top of the oil container, the top of the wick shall not project above the wick guide (zero on the scale );

d) The glass of the door shall be curved to prevent the formation of multiple images; and

e) The joint between the base of the oil container and its body shall be oil-tight.

Wick - Woven solid circular wick of cotton yarn and complying with the following requirements shall be used:

Number of Threads

Casing        17 ends

Filling         9 ends

Picks           6 per cm

PRECAUTIONS

·         The test shall normally be carried out at a room temperature of not less than 15°C; it is recommended that the room temperature and the barometric pressure be recorded.

• Place the lamp in a vertical position completely protected from draughts.

PROCEDURE

·         20 ml of the previously filtered sample is introduced in the clean, dry oil container.

·          A piece of wick is extracted, not less than 12’5 cm in length, with a suitable volatile solvent and it is dried for half an hour at 100 to 110°C.

·         The wick is soaked in the sample under test and is placed in the wick holder, carefully easing out any twists arising from this operation. It is advisable to re-soak the burning end of the wick in the sample.

·         The wick holder is placed in the container and ensured that the air inlet is free from oil. The wick is cut horizontally and trimmed to free the frayed ends so that 6 mm of wick projects from the container.

·         The oil container is maintained at a temperature of 20 to 25°C for 10 minutes. The lamp is inserted and the wick is lighted.

·         The wick is adjusted so that the flame is about 1 cm high and allows the lamp to burn for 5 minutes. The wick is raised until a smoky tail appears, then lowered slowly through the following stages of flame appearances:

a) A long tip, smoke slightly visible, erratic and jumpy flame.

b) An elongated pointed tip with the sides of the tip appearing concave upward.

c) The pointed tip just disappears leaving a very slightly blunted flame Jagged, erratic, luminous flames are sometimes observed near the true flame tip. These are to be disregarded.

d)     The height flame is estimated to the nearest millimetre.

• The smoke point is recorded as observed. To eliminate errors due to parallax, the eye of the observer should be slightly to one side of the centre line, so that a reflected image of the flames seen on the scale on one side of the central vertical white line, and the flame itself is seen against the other side of the scale. A sighting device may also be used to eliminate parallax and to facilitate reading the flame height.

·         The reading for both observations should be identical.

SIGNIFICANCE

• This is an important test for illumination oils for their ability to burn without producing smoke.
• It is used in the assessment of burning quality of aviation fuel. Higher the smoke point better is its domestic use.
• To find aromatic content of the kerosene.

·         This test method provides an indication of the relative smoke producing properties of kerosene’s and aviation turbine fuels in a diffusion flame. The smoke point is related to the hydrocarbon type composition of such fuels.

·          Generally the more aromatic the fuel the smokier the flame. A high smoke point indicates a fuel of low smoke producing tendency.

·         The smoke point (and Illuminometer number with which it can be correlated) is quantitatively related to the potential radiant heat transfer from the combustion products of the fuel. Because radiant heat transfer exerts a strong influence on the metal temperature of combustor liners and other hot section parts of gas turbines, the smoke point provides a basis for correlation of fuel characteristics with the life of these components.

RESULT

S. No.	Sample(ml)	Smoke Point(mm)

            Thus the smoke point experiment was performed and is tabulated below:

ANILINE POINT

AIM

        To determine the aniline point of the given sample.

APPARATUS

• The tube approximately 25mm in diameter and 150mm in length made of heat-resistant glass.
• A Jacket-approximately 37 to 42mm in diameter and 175mm in length made of heat-resistant glass.
• A Stirrer-manually operated, approximately 2mm in diameter soft iron wire.

THEORY

Aniline point

             Aniline is a poor solvent for aliphatic hydrocarbons and excellent one for aromatics. This property is used in the aniline point test. Aniline point of oil is the lowest temperature at which the oil is completely miscible with an equal volume of aniline.

             Equal volumes of the sample and aniline (5 ml each) are heated or cooled with stirring in a jacketed test tube and temperature at which complete miscibility occurs is noted.

              High aniline point indicates that the fuel is highly paraffinic and hence has a high diesel index and very good ignition quality. In case of aromatics the aniline point is low and the ignition quality is poor

 Diesel index

Diesel index is an indication of the ignition quality of a diesel fuel. This is determined by calculation from the specific gravity and the aniline point of the sample. Although it is of the same order as the cetane number, it may differ widely from the cetane number. Higher the diesel index better is the ignition quality of the diesel fuel. It is normally used as a guide to ignition quality of the diesel fuel in the absence of test engine for the direct measurement of cetane number.

              The diesel index is calculated as follows:

(a)    Diesel index = (Aniline point,ºF ׺API)/100

(b)   Diesel index = (Aniline gravity constant)/100

(c)    Diesel index = (Cetane number −10)/0.72

Cetane number

             Cetane number is related to the ignition delay of a fuel in a diesel engine, i.e. how rapidly combustion begins after injection of the fuel into the combustion chamber.

              The shorter the ignition delay period, higher is the cetane number of the fuel

               Cetane number is the index of the ignition quality of a fuel. High cetane number fuels will facilitate easy starting of compression ignition engines, particularly in cold weathers, and faster warm up. These also result in increased engine efficiency and power output, reduced exhaust smoke and odour and combustion noise. In the absence of test engine, the diesel index or the calculated cetane index will give an approximate idea of the ignition quality of the fuel.

                Cetane number= 0.72×Diesel index + 10

PROCEDURE

• The apparatus was dried and cleaned.
• 10ml of aniline and 10ml of the sample were dried and pipetted into the test tube fitted with stirrer and thermometer.
• The thermometer in the test tube was centered to make the immersion mark at the liquid level; it is assured that the thermometer bulb does not touch the side of the tube.
• In the case of not mixing of aniline-sample at normal temperature, heat is applied directly to the jacket tube so that the temperature raised at a rate of 1-3ºC/min till complete miscibility was obtained.
• Stirring is continued and the mixture is allowed to cool at a rate of 0.5 to 1ºC/min.
• Cooling is continued to a temperature of 1 to 2ºC below the first appearance of turbidity.
• The temperature at which the mixture suddenly became cloudy throughout is recorded as the aniline point.

RESULT

Results for the aniline point experiment were found to be

• Aniline point  =
• Diesel index    = 
• Cetane number  =

CLOUD AND POUR POINT EXPERIMENTAL SETUP

CLOUD AND POUR POINT DETERMINATION

AIM

To determine the Cloud point and pour point of the given sample.

REQUIREMENTS

Cloud and pour point apparatus, Thermometer, Ice crystals.

DEFINITIONS

The cloud point of a fluid is the temperature at which dissolved solids are no longer completely soluble, precipitating as a second phase giving the fluid a cloudy appearance. This term is relevant to several applications with different consequences.

Also, the pour point can be defined as the lowest temperature expressed in multiples of 3ºC at which the oil is observed to flow when cooled and examined under prescribed conditions.

THEORY

Cloud point and pour point are indicators of the lowest temperature of utility for petroleum products. Cloud Point gives a rough idea of temperature above which the oil can be safely handled without any fear of congealing or filter clogging. The sample is periodically examined while it is being cooled in the cloud and pour point apparatus. The highest temperature at which haziness is observed (cloud point), or the lowest temperature at which the oil ceased to flow is observed (pour point), is reported as the test result.

The cold filter plugging point test is used to determine the extent to which diesel fuel or gas oil will flow, even though the temperature is below that at which wax crystals normally appear, i.e. cloud point.

Pour point is a well established test to estimate the temperature at which a sample of oil becomes sufficiently solid to prevent its movement by pumping. The pour point indicates the waxy nature of the oils.

SAMPLES SHOWING CLOUD AND POUR POINT

                                   

                                  

PROCEDURE

Measuring cloud point of petroleum product:

The test oil is required to be transparent in layers 40mm in thickness (in accordance with ASTM D2500). The crystals of the sample typically first form at the lower circumferential wall with the appearance of a whitish or milky cloud. The cloud point is the temperature at which these crystals first appear.

The test sample is first poured into a test jar to a level approximately half full. A cork carrying the test thermometer is used to close the jar. The thermometer bulb is positioned to rest at the bottom of the jar. The entire test subject is then placed in a constant temperature cooling bath on top of a gasket to prevent excessive cooling.

At every 1°C, the sample is taken out and inspected for cloud then quickly replaced. Successively lower temperature cooling baths may be used depending on the cloud point. Lower temperature cooling bath must have temperature stability not less than 1.5 K for this test.

Measuring pour point of petroleum product:

Two pour points can be derived which can give an approximate temperature window depending on its thermal history. Within this temperature range, the sample may appear liquid or solid. This peculiarity happens because sample crystals form more readily when it has been heated within the past 24hrs and contributes to the lower pour point.

The upper pour point is measured by pouring the test sample directly into a test jar. The sample is then cooled and then inspected for pour point as per the usual pour point method.

The lower pour point is measured by first pouring the sample into a stainless steel pressure vessel. The vessel is then screwed tight and heated to above 100^oC in an oil bath. After a specified time, the vessel is removed and cooled for a short while. The sample is then poured into a test jar and immediately closed with a cork carrying the thermometer. The sample is then cooled and then inspected for pour point as per the usual pour point method

RESULT

The pour point of the given sample was found to be      ---------⁰C.

The cloud point of the given sample was found to be     ---------⁰C

                                

MELTING POINT DETERMINATION

AIM

            To determine the melting point of given sample. And also its solidification point.

APPARATUS REQUIRED

• Thermometer
• Test tube
• Hot plate
• Burette stand

DEFINITION

When a solid substance is heated, typically it will melt; that is to say, at some temperature the solid will begin to liquefy and by some slightly higher temperature all of the solid will have become liquid. The melting point (actually melting point range) of a compound is then defined as the temperature at which an observer can first see liquid forming from the solid to the temperature where the last particle of solid has become liquid.

PURPOSE

• There are several purposes for doing this experiment. The first is to learn how to determine the melting range of a solid substance accurately. When a solid substance is prepared its melting point is usually determined to aid in its identification and to get some idea of its purity.

• The second is to observe the effect of the purity of a substance on its melting behavior. Pure substances usually have melting point ranges of a degree or two; impure substances (which are mixtures of two or more substances) often have wider ranges.

• The third is to use a physical constant of an unknown substance – its melting point – to identify it from among several possibilities.

PROCEDURE

• Melting points are usually determined by placing one or two milligrams of the material is to be tested into a melting point capillary, and heating the capillary and a thermometer together, and observing over what temperature range the material melts. The melting point capillary is a thin-walled glass tube, about 100 mm in length and not more than 2 mm in outside diameter, sealed at one end.

• The bulb end of the thermometer is inserted, along with the attached capillary tube. The capillary tube and the thermometer are clamped to the stand.

• The accurate melting point is achieved by heating the sample at a rate of 1 to 2 degrees per minute.

•  If you have no idea what the melting point of your sample is, you have two choices at this point. (1) You could start at room temperature and warm at the recommended rate until the solid melts. This could take more than an hour. (2) You could start at room temperature and warm at about 10 degrees a minute and obtain an approximate melting point.

• Then, after the apparatus has cooled below the sample's melting point, replace the sample (and capillary) with a new one, and heat slowly until the sample has melted, thus getting an accurate melting point.

               

• The test tube is kept in air bath and the temperature is noted for every 30 seconds until it gets completely solidified.

SIGNIFICANCE

It is used for compound identification and estimation of purity

MELTING POINT RANGE OF DIFFERENT COMPOUNDS

RESULT

            Thus the melting point range of sample was determined from the graph. It is found to be

COPPER STRIP CORROSION TEST – TEST BOMB

 

                   COPPER STRIP CORROSION TEST

AIM

To detect the corrosiveness of the given sample using copper strip corrosion test.

PRINCIPLE        

The method covers the detection of corrosiveness to copper of aviation gasoline from tractor fuel, solvent, kerosene, diesel, fuel oil, lube oil, certain other petroleum products.

A polished copper strip is immersed in a given quantity of sample and heated at a temperature and for a time characteristics of the material being tested. At the end of this period, the copper strip is removed, washed and compared with copper strip corrosion standards. It is particularly important that all types of feed sample which should pass a tarnished strip classification. We collected clean glass bottles, plastic bottles or other suitable containers that will not affect the corrosiveness properties of the sample.

REQUIREMENTS

·         Copper strip corrosion test bomb

·         Constant temperature water bath

·         Polishing ice

·         Glass test tube

·         Polishing paper

Significance and Use

         

 This test method is suitable for setting specifications, for use as an internal quality control tool, and for use in development or research work on industrial aromatic hydrocarbons and related materials. It also gives an indication of the presence of certain corrosive substances which may corrode equipment, such as acidic compounds or sulfur compounds.

PROCEDURE

·         The test is to be operated at 50^oC constant temperature.

·         The bath is set at the desired working temperature and waits for 20 minutes of time after the start.

·         The copper strip is prepared for performing test. It is washed properly with solvent (acetone) and surface of strip is prepared by rubbing with silicon carbide grid paper.

·         Clamp the strip with ice and polish it until uniform rubbing, when strip is clean immerse it in prepared sample.

·         The strip is kept into 30 ml of sample which is kept inside the test bomb and the lid is screwed tight.

·         After two hours in the bath the bomb is withdrawn and it is cooled with water.

·         The bomb is opened, the test tube is taken out and carefully the strip is withdrawn from the   sample.

·         The strip is compared with ASTM corrosion standards comparison chart and report the tarnish level.

          

RESULT

The corrosiveness of the given sample is found out using the copper strip and comparing it with ASTM standards and its value is found to be ---------------------------

                                                                  

                             

                                      

CONGEALING POINT OF WAX

AIM

To determine the congealing point of given sample wax.

DEFINITION

Congealing point may be defined as the temperature of which molten petroleum wax when cooled under prescribed conditions ceases to flow.

OUTLINE

A sample of wax is melted and droplet is made to adhere to the bulb of the thermometer. Using a pre warmed flask as an air jacket, the droplet on the bulb is allowed to cool at a fixed rate until it congeals. The congealing point is observed as the temperature at which the droplet ceases to flow as the thermometer is turned.

APPARATUS REQUIRED

Thermometer, Erlenmeyer flask, Cork or Rubber stopper.

PROCEDURE

Ø  The thermometer is adjusted through the stopper so that the bottom of the bulb will be 10 to 15 mm above the bottom of the Erlenmeyer flask when the stopper is fitted snugly in the flask.

Ø  After making this adjustment, the thermometer and stopper are removed from the flask, carefully without changing the position of the stopper relative to the thermometer stem.

Ø  Approximately 50gm of sample is placed, which is representative of the material under inspection in a porcelain evaporating dish or other suitable container.

Ø  The empty Erlenmeyer flask is placed (without the thermometer assembly) and the container holding the sample in a temperature-controlled oven set at 99 ± 3⁰c (210 ± 5⁰f) until the sample and flask reach oven temperature.

Ø  The sample is removed from the oven and the thermometer bulb is completely immersed without covering any part of the thermometer stem with sample. The sample is stirred gently with the thermometer until the mercury column has stopped rising.

Ø  While holding the thermometer bulb in the molten wax sample, the heated flask is removed from the oven, using a towel or gloves to project the hands. Now carefully the thermometer from the sample adhering to the bulb is removed.

Ø  The thermometer is held in a position firmly and is fit and stoppered into the flask. The assembly is kept in a horizontal position.

Ø  While the drop on the thermometer bulb is observed at an eye level position. The thermometer and flask are rotated about a horizontal axis. a steady and even rate  are used for each continuous full revolution, and each revolution is completed in not less than 2 sec not more than 3 sec.

Ø  The completion of each revolution should not be paused any longer than required to reindex the fingers for the next full and continuous rotation. When the drop is observed to rotate with the bulb immediately the thermometer to the nearest 0.25⁰c (0.5⁰F) is read and this determination is recorded.

Ø  A repeat determination is made on the wax sample. If the variation of these two determinations does not exceed 1⁰c (2⁰f) the average of these determinations is recorded as a congealing point of the sample under test.

Ø  If the variation of two determinations is greater the 1⁰c (2⁰c) additional reading is recorded, and the average of the three determination is recorded as the congealing point.

Significance

       Congealing point is a wax property that is of interest to many petroleum wax consumers. It indicates temperature at which sample when cooled under prescribed conditions develop a se or resistance to flow. At that temperature the wax maybe at or close to the solid state or it may be semisolid and quite unctuous depending on the composition of the wax congealing property is associated with the formation of a gel structure as the sample cools.

Result

       The average of the multiple determinations as the congealing point of the given sample