Soran University Faculty of Engineering Chemical Engineering Department

2015 -2016

Names: Abdulsamad Alhamawande.

.lLubricating Oi Title:

Supervision: Dr.Ibtisam.

Date: 2015-05-20.

Background:

Since the Roman era, many liquids, including water, have been used as lubricants

to minimize the friction, heat, and wear between mechanical parts in contact with

each other. Today, lubricating oil, or lube oil, is the most commonly used lubricant

because of its wide range of possible applications. The two basic categories of lube

oil are mineral and synthetic. Mineral oils are refined from naturally occurring

petroleum, or crude oil. Synthetic oils are manufactured polyalphaolefins, which

are hydrocarbon-based polyglycols or ester oil.

Although there are many types of lube oils to choose from, mineral oils are the

most commonly used because the supply of crude oil has rendered them

inexpensive; moreover, a large body of data on their properties and use already

exists. Another advantage of mineral-based lube oils is that they can be produced

in a wide range of viscosities—viscosity refers to the substance's resistance to

flow—for diverse applications. They range from low-viscosity oils, which consist of

hydrogen-carbon chains with molecular weights of around 200 atomic mass units

(amu), to highly viscous lubricants with molecular weights as high as 1000 amu.

Mineral-based oils with different viscosities can even be blended together to

improve their performance in a given application. The common 1OW-30 motor oil,

for example, is a blend of low viscous oil (for easy starting at low temperatures)

and highly viscous oil (for better motor protection at normal running

temperatures).

First used in the aerospace industry, synthetic lubricants are usually formulated for

a specific application to which mineral oils are ill-suited. For example, synthetics

are used where extremely high operating temperatures are encountered or where

the lube oil must be fire resistant. This article will focus on mineral-based lube oil.

Raw Materials:

Lube oils are just one of many fractions, or components, that can be derived from

raw petroleum, which emerges from an oil well as a yellow-to-black, flammable,

liquid mixture of thousands of hydrocarbons (organic compounds containing only

carbon and hydrogen atoms, these occur in all fossil fuels). Petroleum deposits

were formed by the decomposition of tiny plants and animals that lived about 400

million years ago. Due to climatic and geographical changes occurring at that time

in the Earth's history, the breakdown of these organisms varied from region to

region.

Because of the different rates at which organic material decomposed in various

places, the nature and percentage of the resulting hydrocarbons vary widely.

Consequently, so do the physical and chemical characteristics of the crude oils

extracted from different sites. For example, while California crude has a specific

gravity of 0.92 grams/milliliter, the lighter Pennsylvania crude has a specific gravity

of 0.81 grams/milliliter. (Specific gravity, which refers to the ratio of a substance's

weight to that of an equal volume of water, is an important aspect of crude oil.)

Overall, the specific gravity of crudes ranges between 0.80 and 0.97

grams/milliliter.

Depending on the application, chemicals called additives may be mixed with the

refined oil to give it desired physical properties. Common additives include metals

such as lead or metal sulphide, which enhance lube oil's ability to prevent galling

and scoring when metal surfaces come in contact under extremely high pressures.

High-molecular weight polymerics are another common additive: they improve

viscosity, counteracting the tendency of oils to thin at high temperatures.

Nitrosomines are employed as antioxidants and corrosion inhibitors because they

neutralize acids and form protective films on metal surfaces.

The manufacturing process:

Lube oil is extracted from crude oil, which undergoes a preliminary

purification process (sedimentation) before it is pumped into

efficiency fractionating tower, 25 to -fractionating towers. A typical high

ters) in diameter and up to 400 feet (122 meters) 35 feet (7.6 to 10.6 me

tall, is constructed of high grade steels to resist the corrosive

compounds present in crude oils; inside, it is fitted with an ascending

of series of condensate collecting trays. Within a tower, the thousands

hydrocarbons in crude oil are separated from each other by a process

As the vapors rise up through the tower, the fractional distillation. called

various fractions cool, condense, and return to liquid form at different

rates determined by their respective boiling points (the lower the boiling

Natural gas point of the fraction, the higher it rises before condensing).

reaches its boiling point first, followed by gasoline, kerosene, fuel oil,

.lubricants, and tars

Sedimentation:

1) The crude oil is transported from the oil well to the refinery by pipeline or

tanker ship. At the refinery, the oil undergoes sedimentation to remove any water

and solid contaminants, such as sand and rock, that maybe suspended in it. During

this process, the crude is pumped into large holding tanks, where the water and oil

are allowed to separate and the contaminants settle out of the oil.

Fractionating:

2) Next, the crude oil is heated to about 700 degrees Fahrenheit (371 degrees

Celsius). At this temperature it breaks down into a mixture of hot vapor and liquid

that is then pumped into the bottom of the first of two fractionating towers. Here,

the hot hydrocarbon vapors float upward. As they cool, they condense and are

collected in different trays installed at different levels in the tower. In this tower,

normal atmospheric pressure is maintained continuously, and about 80 percent of

the crude oil vaporizes.

3) The remaining 20 percent of the oil is then reheated and pumped into a second

tower, wherein vacuum pressure lowers the residual oil's boiling point so that it

can be made to vaporize at a lower temperature. The heavier compounds with

higher boiling points, such as tar and the inorganic compounds, remain behind for

further processing.

Filtering and solvent extraction:

4) After further processing to remove unwanted compounds, the lube oil that has

been collected in the two fractionating towers is passed through several ultrafine

filters, which remove remaining impurities. Aromatics, one such contaminant,

contain six-carbon rings that would affect the lube oil's viscosity if they weren't

removed in a process called solvent extraction. Solvent extraction is possible

because aromatics are more soluble in the solvent than the lube oil fraction is.

When the lube oil is treated with the solvent, the aromatics dissolve; later, after

the solvent has been removed, the aromatics can be recovered from it.

Additives, inspection, and packaging:

5) Finally, the oil is mixed with additives to give it the desired physical properties

(such as the ability to withstand low temperatures). At this point, the lube oil is

subjected to a variety of quality control tests that assess its viscosity, specific

gravity, color, flash, and fire points. Oil that meets quality standards is then

packaged for sale and distribution.

Quality Control:

Most applications of lube oils require that they be nonresinous, pale-colored,

odorless, and oxidation-resistant. Over a dozen physical and chemical tests are

used to classify and determine the grade of lubricating oils. Common physical tests

include measurements for viscosity, specific gravity, and color, while typical

chemical tests include those for flash and fire points.

Of all the properties, viscosity, a lube oil's resistance to flow at specific

temperatures and pressures, is probably the single most important one. The

application and operating temperature range are key factors in determining the

proper viscosity for an oil. For example, if the oil is too viscous, it offers too much

resistance to the metal parts moving against each other. On the other hand, if it

not viscous enough, it will be squeezed out from between the mating surfaces and

will not be able to lubricate them sufficiently. The Saybolt Standard Universal

Viscometer is the standard instrument for determining viscosity of petroleum

lubricants between 70 and 210 degrees Fahrenheit (21 and 99 degrees Celsius).

Viscosity is measured in the Say bolt Universal second, which is the time in seconds

required for 50 milliliters of oil to empty out of a Saybolt viscometer cup through a

calibrated tube orifice at a given temperature.

The specific gravity of an oil depends on the refining method and the types of

additives present, such as lead, which gives the lube oil the ability to resist

extreme mating surface pressure and cold temperatures. The lube oil's color

indicates the uniformity of a particular grade or brand. The oil's flash and fire

points vary with the crude oil's origin. The flash point is the temperature to which

an oil has to be heated until sufficient flammable vapor is driven off so that it will

flash when brought into contact with a flame. The fire point is the higher

temperature at which the oil vapor will continue to burn when ignited.

Common engine oils are classified by viscosity and performance according to

specifications established by the Society of Automotive Engineers (SAE).

Performance factors include wear prevention, oil sludge deposit formation, and oil

thickening.

The Future:

based lubricating oil is limited, because the natural -e future of mineralTh

renewable. Experts -supplies of petroleum are both finite and non

estimate the total recoverable light to medium petroleum reserves at 1.6

based -used. Thus, synthetictrillion barrels, of which a third has been

oils will probably be increasingly important as natural reserves dwindle.

This is true not only for lubricating oil but also for the other products

.that result from petroleum refining

:The Flowchart

Lubricating oil is refined from crude oil. After undergoing a purifying

process colled sedimentation, the crude oil is heated in huge

which can be used to make —fractionating towers. The various vapors

f and are boil of—fuel, waxes, or propane, among other substances

collected at different points in the tower. The lube oil that is collected is

.filtered, and then additives are mixed in

The Reference:

http://www.madehow.com/Volume-1/Lubricating-Oil.html