JSC «Kazakh-British Technical University»
School of Chemical Engineering
Chemistry of Oil and Gas
REPORT
Laboratory work #6
«Standard Test Method for Octane Number of Gasoline. Properties of Gasoline.»
Done by: Kanapiyeva Sharizada
Checked by: MBA, senior-lecturer,
Kamshat Umbetova
Almaty, 2021
INTRODUCTION
Octane number is a measure of the knocking characteristics of a fuel in a laboratory gasoline engine. It
is determined by measuring its knocking value compared to the knocking of a mixture of n-heptane and
isooctane or 2-2-4-trimethylpentane.
Octane number of 0 is assigned to pure heptane.
Octane number of 100 to 2-2-4-trimethylpentane.
Octane number of 70 is a mixture of 30% heptane and 70% isooctane.
There are two specific octane numbers in use. The motor octane number (MON) reflects the engine
performance at highway conditions with high speeds (900 rpm), while the research octane number
(RON) corresponds to the low-speed city driving (600 rpm). RON is typically higher than MON because
of engine test efficiencies. The posted octane number is an average of MON and RON.
For diesel fuel cetane number is used. It represents the percentage of pure cetane (n-hexadecane) in a
blend of cetane and alpha methyl-naphthalene that matches the ignition quality of a diesel fuel sample.
The cetane index is a number calculated from the average boiling point and gravity of a petroleum
fraction in the diesel fuel boiling range, which estimates the cetane number of the fraction according to
ASTM D976.
Knocking (also called detonation) in spark-ignition internal combustion engines occurs when
combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition by the
spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal
combustion front.
The sensitivity of the performance of the fuel to the two types of driving conditions is the difference
between RON and MON. Low sensitivity of fuel.
PROCEDURE
Fill the cylinder of octane meter up to the mark, close the cylinder and turn on the octane meter. On the
screen of the octane meter research octane number will appear. Push on the “On” button again to see the
motor octane number.
Studying the characteristic properties of gasoline
1. Observe, if the gasoline sample contains mechanical impurities;
2. Measure the density of gasoline by areometer (at given temperature);
3. Mix 10 ml of gasoline with 10 ml of water, and separate water from gasoline by separating funnel.
Divide obtained water into two test tubes:
add to the first one 1-2 drops of phenolphthalein
to the second one 1-2 drops of methyl orange.
Observe if the gasoline contains soluble acids or bases.
ANALYSIS OF RESULTS
1. Measure the posted octane number and sensitivity of the fuel:
Posted octane number (PON) = (RON + MON)/2
Sensitivity of the fuel = (RON – MON)
Octane number: RON – 96
MON – 86,5
PON = (RON + MON)/2 = (96+86,5)/2 = 91,25
Sensitivity of the fuel = (RON – MON) = 96 – 86,5 = 9,5
2. Fill the table the properties of gasoline
Properties Gasoline
Density 0,742 kg/m3
Impurities No
Acids (color of methyl orange)
Bases (color of phenolphthalein) +
ABOUT ALL WORK PROCEDURE
In the first task we used an octane meter to measure the octane number, filled the cylinder of the octane
meter and waited 10 seconds for the exact result of the octane number according to the research method,
pressing the button on the display we found the octane number of the motor method. Using the formulas
we find posted octane number and sensitivity of the fuel.
Second task
Using 10 ml of water and 10 ml of gasoline, mix them and separate the water, divide into two vials and
add phenolphthalein to the first and methyl orange to the second. The added phenolphthalein has not
changed color and remains colorless, this means we have acid. The added methyl orange also
remained orange.
Question:
1. Difference between octane and cetane number?
Octane number gives an idea about the performance of a fuel whereas cetane number gives an idea about
the ignition of a fuel.
2. Detonation meaning
The premature combustion of fuel in an internal combustion engine, causing pinking.
CONCLUSION:
We got introduced to the octane number and its types, tried to measure it, and also got familiar with the
characteristics of gasoline.
