2. Content
Gasoline
Source of Gasoline
Petroleum Refining
Components of a Refinery
Fractional Distillation
Chemical Processing
Properties of gasoline
Gasoline (4-Stroke) Engine
Octane Rating
Gasoline Additives
MTBE
3. Gasoline
Gasolines is a volatile, flammable
mixtures of hydrocarbons that have boiling
ranges from 100 to 400°F (38 to 205°C) as
determined by the ASTM method. Most
gasoline is consumed as a fuel in spark-
ignition engines, primarily those which
power automobiles and certain airplanes.
Octane : eight carbons C8H18
It is the main ingredient in gasoline
4. Source of Gasoline
Gasoline comes from petroleum oil which comes from organisms breaking down
over million of years in the mid 1800s ,people began trying to separate it out ,to
refine it .Now there is all the kind of the oil and liquids and they burn really well.
5. Petroleum Refining
oil refinery is an industrial plant where crude oil is processed and
refined into more useful petroleum products such as gasoline, jet fuel
and diesel.
7. Fractional Distillation
The hydrocarbons in crude oil have different boiling points, according to the
number of carbon atoms their molecules contain and how they are arranged.
Fractional distillation uses the difference in boiling point to separate the
hydrocarbons in crude oil.
The fractionating column is cooler at the top than the bottom, so the vapors
cool as they rise.
8. Vapors condense onto a tray when they reach the part of the column which is
cooler than their boiling point.
As the last gases from the bottom of the column pass through the holes in a
tray, any lighter hydrocarbons still in the condensed liquid are boiled off, and
rise through the column.
Fractional Distillation
9. Chemical Processing
Few components from fractional distillation column ready for market. Most of
the products must be chemically processed to make other fractions. Regarding
the Gasoline only 40% from distilled crude oil.
After distillation, one fraction can be changed into another by two methods of
chemical processing:
Cracking process
Unification process
10. Cracking
Cracking breaks large chains into smaller chains.
After various hydrocarbons are cracked into smaller hydrocarbons, the products
go through another fractional distillation column to separate them
11. Unification
Unification combines smaller hydrocarbons into larger ones
A reformer combines chains to make naphtha into gasoline
A significant by-product of this reaction is hydrogen gas, which is then
either used for hydrocracking or sold.
12. Properties of gasoline
Gasoline properties are specified by law or government agencies. Standard
measurements for most properties are developed and published by organizations such
as the American Society for Testingand Materials (ASTM) and the International
Organizationfor Standardization (ISO).
Refineries produce gasoline from blend stocks derived from various processes – crude oil
distillation, catalytic reforming, fluid catalytic cracking (FCC), thermal cracking,
hydrocracking, alkylation, isomerization and catalytic polymerization. Finished products
sold in the market include additives, which inhibit oxidation, inhibit corrosion, passivate
trace metals, reduced position of carbon on intake valves and combustion chambers, and
minimize the formation ofice in cold weather.
13. Gasoline (4-Stroke) Engine
Burns fuel and air in enclosed
space producing hot gases
Allows heat to flow from hot
engine to cold outside air
Converts some of this heat into
useful work
The four strokes of the cycle are induction, compression, power, and exhaust.
Each corresponds to one full stroke of the piston, therefore the complete cycle requires
two revolutions of the crankshaft to complete.
14. Induction Stroke
During the induction stroke, the piston moves downward, drawing a fresh
charge of vaporized fuel/air mixture.
• The carburetor mixes the fuel and air
15. Compression Stroke
At the top of the compression stroke the spark plug fires, igniting the
compressed fuel.
As the fuel burns it expands, driving the piston downward.
Chemical energy converted to thermal energy converted to mechanical energy.
16. Power Stroke
As the piston rises the poppet valve is forced shut by the increased
cylinder pressure.
Flywheel momentum drives the piston upward, compressing the fuel/air
mixture.
Compressed Fuel is easier to ignite
17. Exhaust Stroke
• At the bottom of the power stroke, the exhaust valve is opened by the cam/lifter
mechanism.
• The upward stroke of the piston drives the exhausted fuel out of the cylinder
18. Gasoline and 4-stroke Engines
A 4-stroke engine is designed to run on a refined mixture of hydrocarbons from
C7– Heptane and C8–Octane.
This mixture is called Gasoline
C7 and C8 vaporize at temperatures below the boiling point of water. –
That's why if you spill gasoline on the ground it evaporates very quickly
19. Octane Rating
The octane rating of gasoline tells you how much the fuel can be compressed before it
spontaneously ignites.
Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent
heptane
Most gas stations offer three octane grades:
regular, usually 87 octane
mid-grade, usually 89 octane
premium usually 92 or 93.
20. Knocking
Knocking occurs when gas ignites by compression rather than because of the
spark from the spark plug.
Problems:
• Annoying
• Reduces efficiency
• Damages engine
Heptane handles compression very poorly
Octane handles compression very well
As a solution for this is increase the octane rating of the gasoline by more
further chemical processes
21. Gasoline Additives
it was discovered that you can add a chemical called tetraethyl lead to gasoline and
significantly improve its octane rating.
Lower octane grades of gasoline could be made usable by adding this chemical.
• TEL was cheap to manufacture
• Most oil companies could process TEL at their refineries
• This increased profits for the oil company.
Tetraethyl Lead (TEL)
• Due to the combustion of TEL in gasoline, the Earth became covered in a thin layer
of lead.
• Even glacial ice at the north pole recorded an alarming increase of lead during the
mid to late 1900s
22. MTBE
• MTBE has been used in U.S. gasoline at low levels since 1979 to replace TEL
to increase its octane rating and help prevent engine knocking.
• A hydrocarbon molecule that is created at a refinery from methanol.
• Gasoline can contain as much as 10 percent to 15 percent MTBE.
• The main problem with MTBE is that it is thought to be carcinogenic and it
mixes easily with water
• If gasoline containing MTBE leaks from an underground tank at a gas station,
it can get into groundwater and contaminate wells.
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