TO: MISS SITI AFIFAH MUDA Code: CPD 20103

From: (Student Name/Section) ID Number

1) NUR KHAIRUNNISA BINTI SOBERI 1) 55102118033
2) MUHAMMAD AL-BAIHAQI BIN RAFIDI 2) 55102118030
3) MOHD KHAIRUL FATHY BIN M. ASRAR 3) 55102118037
4) MUHAMMAD FAIZ BIN MUHAMAD SUBRI 4) 55102118032
5) 5)
6) 6)
Title of experiment: DETERMINATION OF API GRAVITY Date of experiment: 04/03/2020

Received by: Date Due: 02/06/2020

VER VERY
POOR GOO EXCELLENT
CRITERIA Y GOO
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1.0 OBJECTIVES (TOTAL PERCENTAGE, 5%) 1 2 3 4 5
State the objectives of the experiment or report (in point form).
2.0 SUMMARY (1 PAGE ONLY) (TOTAL PERCENTAGE, 10%) 2 4 6 8 10
Brief review on the objectives of the experiment, main experimental results and
discussions deemed significant and conclusions obtained from the work.
3.0 INTRODUCTION & THEORY (1-2 PAGES 3 6 9 12 15
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2. Summary of theories including formulations related to the experimental work.
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4.0 RESULTS AND DISCUSSIONS/TUTORIAL (MAXIMUM 5 PAGES)
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1. Data are presented as deemed suitable with complete label and units
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3. Discuss on the findings and relations to the theory and objective of experiment
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5.0 CONCLUSIONS AND RECOMMENDATIONS (TOTAL PERCENTAGE,
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2. Suggest improvements in apparatus or measurement procedure, or
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Laboratory Report Submission Form

Petrochemicals & Petroleum Refining
Technology (CPD 20103)

Date of Submission:
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Experiment title:

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1.0 OBJECTIVES

i. To determine the specific gravity of oil using hydrometer and density meter.

ii. To compare the specific gravity and API gravity of different oils.

2.0 SUMMARY

The experiment conducted is Experiment 2: Determination of API Gravity. There are two
objectives that need to be investigated and achieved that is to determine the specific gravity of oil
using hydrometer and density meter and to compare the specific gravity and API gravity of
different oils. The result expected is according to the normal API Gravity and specific gravity for
each petroleum products. From the results, the specific gravity and API Gravity will be
compared. The types of oil used were lubricant oil, diesel, kerosene and petrol. The average
density readings of each oil were studied using a hydrometer and density meter which was then
calculated for specific gravity. To determine the accuracy of the equipment respectively, the
density values for oils were then compared with the standard value and it had been stated that the
density meter gave more accurate readings. The conclusion is then finalized at the conclusion
section whether the objectives is achieved or not.
3.0 INTRODUCTION AND THEORY

Through definition, API gravity is defined as American Petroleum Institute gravity is an

arbitrary scale that expresses the gravity or density of liquid oil products. The gravity value of
the API is between 10 and 50° API. API gravity is the most commonly used property in the
petroleum industry for classifying crude oil and refined petroleum products. It was also used to
predict many other characteristics of petroleum oils, such as the Sulphur content [ CITATION
Yas13 \l 1033 ]. The American Petroleum Institute (API) adopted an oil hydrometer lighter than
water for which the scale, called the API scale, is

141
° API = −131.5
γ

ρ oil
Where: γ , specific density at 60 ℉ =
ρ water

ρ
Where: water =
1 g 1000kg
∨
cm3 m3

The most common methods for determining a liquid's density or specific gravity are:

- Hydrometer

- Density meter

The API gravity is the standard specific gravity used by the oil industry, which compares oil
density to water density through a formula designed to ensure measurement accuracy. Less dense
oil or "light oil" is preferred to denser oil because it contains greater quantities of hydrocarbons
that can be converted into gasoline. The API gravity value was used to determine the oil quality
and to categorize the type of oil itself where the API gravity value is increased by lower specific
gravity value.

Basically, the API gravity is used to assess the classification of oil into 4 types that are small,
medium, heavy and extra heavy:
 1. Light crude oil is defined as having API gravity higher than 31.1 ºAPI.

2. Medium crude oil is defined as having API gravity between 22.3 ºAPI and 31.1 ºAPI.

3. Heavy crude oil is defined as having API gravity less than 22.3 ºAPI.

4. Extra heavy crude oil is defined as having API gravity less than 10 ºAPI.

[ CITATION API15 \l 1033 ]

Methods of the hydrometer and density meter are commonly used to determine the actual
gravity of oil and to compare specific gravity and API gravity of crude petroleum products and
petroleum liquids. The hydrometer and density meter differs both manually and digitally in the
way reading is done. The hydrometer is also used for determined the gravity of oil in the oil
field. When a hydrometer is put in oil it can float vertically with its axis after a mass of oil equal
to the mass of hydrometer has been displaced. The hydrometer can be used in a pressure cylinder
at atmospheric pressure or by any other pressure [ CITATION Yas13 \l 1033 ]. The portable density
meter is an effective instrument for determining sample density. Density is determined by an
oscillating, hollow U-tube. The frequency of U-tube vibration is directly related to the liquid
sample density. Temperature is determined simultaneously, and the temperature adjustment is
performed automatically by the instrument.

Such two techniques are used to assess the mass, relative density or API gravity of crude
petroleum, petroleum products, or mixtures of petroleum and non-petroleum products that are
typically classified as liquids and that have a Reid vapor pressure of 1.8 bar (179 kPa) or less by
a glass hydrometer test. Generally, the density meter is more accurate compared to the
hydrometer because it is auto-read by automated calculation and allows less errors to occur when
performing the experiment. By comparison, the hydrometer is less reliable due to many factors
such as hydrometer continuing to bouncing up and down and causing parallax error easily.
4.0 RESULTS AND DISCUSSIONS/TUTORIAL

RESULT

Table 1: Determination of specific gravity using density meter

Materials Experimental Specific Gravity API Gravity

(°)
Run 1 Run 2 Run 3 Average
Petrol 0.769 0.765 0.764 0.766 53.26
Diesel 0.846 0.845 0.845 0.845 35.96
Kerosene 0.837 0.837 0.837 0.837 36.56
Lubricating Oil 0.845 0.845 0.845 0.845 35.96

Table 2: Determination of specific gravity using hydrometer

Materials Experimental Specific Gravity API Gravity

(°)
Run 1 Run 2 Run 3 Average
Petrol 0.762 0.762 0.762 0.762 54.19
Diesel 0.845 0.845 0.845 0.845 35.96
Kerosene 0.839 0.839 0.839 0.839 37.15
Lubricating Oil 0.860 0.860 0.860 0.860 33.03

DISCUSSION
 The objectives of this experiment are to determine the specific gravity of oil using the
hydrometer and density meter and to compare between the specific gravity and API gravity of
different oils. The multiple oils used included lubricating oil, gasoline, kerosene, and gas, and
two separate forms of measurement instruments were used that were hydrometer and pressure
meter.

From the data obtained, the API gravity from each oil were calculated. API gravity is
short for gravity of the American Petroleum Institute, an analogous calculation used to assess the
weight of petroleum products when compared with vapor. If a substance has more than 10 API
gravity it is called a light oil that floats on water. If the API gravity of the liquid is less than 10 it
will sink and fall into category of heavy oil. [ CITATION Pab19 \l 1033 ] Meanwhile, specific
gravity is the ratio of an object's mass to a reference material. Based on its value, the particular
gravity can be expected if the object sinks or floats in the reference substance. The comparison
material is typically water and has a density of 1 gram per milliliter or 1 gram per cubic
centimeter at all times. [ CITATION Wan17 \l 1033 ] According to the result, lubricating oil has the
maximum value of density with the lowest value of API gravity whereas petrol has the lowest
value of density with the highest value of API gravity.

By referring to table 1 and 2, it can be concluded that petrol oil is light oil and lubricating
oil heavy oil. Lubricating oil shows denser compared with petrol. Thus, the lubricating oil's
viscosity is higher compared to petrol. One of the properties that can be contrasted is that heavy
oil is based on their flash point to show either lubricating oil or fuel. Petrol flash point is in the
range of 100 – 250 while lubricating oil is 420 – 485. The separation of lubricating oil from
petroleum crude oil therefore requires high energy. Last but not least, comparison with the
hydrometer, the density meter displays more precise reading. This is because the experimental
density and basic gravity values are very similar to the predicted density values for all the
materials and specific gravity values by utilizing density meters instead of hydrometers.
5.0 CONCLUSION AND RECOMMENDATION

This experiment can be concluded that density meter is better to be used for determination
specific gravity for oil than hydrometer. This statement is proved by result obtained show the
reading for specific gravity using density meter is higher than hydrometer. As example reading
for petrol is 0.766 for density meter and 0.762 using hydrometer. The result obtained is same
with theoretical result. This experiment can also be concluded that the specific gravity for
lubricant oil is higher diesel followed by kerosene and petrol. The result shows the specific
gravity reading for lubricant oil is 0.860 followed by 0.845, 0.839 and 0.762 for diesel, kerosene
and petrol (hydrometer reading). Density meter also show the same order. Therefore, specific
gravity reading related to density reading which mean lower the specific gravity, lower the
density.

In this experiment, there are several things that can do to improve the effectiveness in
result. One of it is to make sure equipment use for determine the reading is well prepared. For
density meter, the tube must be cleaned with the solution that want to be measure. If we want to
measure the reading for petrol, me must clean the tube with petrol. Furthermore, the hydrometer
might touch the side wall of measuring cylinder and lead to incorrect data retrieve from the scale
of hydrometer. It was therefore recommended that the hydrometer should float freely without
touching the side wall of the measuring cylinder before the reading was recorded. Last but not
least is the eye level for hydrometer. Make sure the eye level is correct which is your eyes same
level with liquid level.
 REFERENCES

al., Y. e. (2013, January 25). Quality and Chemistry of crude oils. Retrieved from
academicjournals.org: https://academicjournals.org/article/article1379954058_Yasin
%20et%20al.pdf
API Gravity. (2015). Retrieved from petroleum.co.uk: http://www.petroleum.co.uk/api
Pabón, R. E. (2019). Crude oil spectral signatures and empirical models to derive API gravity. .
Retrieved from https://www.sciencedirect.com/science/article/pii/S0016236118316478
Wang, Y. S. (2017). Reliability of measurement and genotype× environment interaction for
potato specific gravity. Retrieved from
https://acsess.onlinelibrary.wiley.com/doi/abs/10.2135/cropsci2016.12.0976