This document provides an overview of petroleum refining. It begins by discussing different forms of fossil fuels like coal and natural gas, and explains that petroleum produces fewer emissions than coal during production. Crude oil contains hydrocarbons like paraffins, naphthenes and aromatics. Crude oils are classified based on properties like sulfur content, density and boiling points. Major benchmark crude oils from different regions are listed along with their properties. The refining process converts crude oil into valuable products like gasoline and diesel through distillation units and catalytic cracking. The goal of refining is to remove impurities from crude oil and produce higher value products.

1. A Brief Introduction to Petroleum Refining
By
Samarshi Chakraborty
Postdoctoral Fellow
IIT Kanpur
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2. Different Forms of Fossil Fuel
Fossil Fuel
Coal Petroleum
Natural
Gas
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3. Why Petroleum?
• Extraction of coal is very disruptive to surface and
underground environments. Coal removal results in large
amounts of waste products that can be harmful to the
environment. Groundwater can become contaminated during
mining and surface mining can be contaminated by leftover
waste. Pollutants are emitted during coal burning and may
cause acid rain, global warming and climate change.
• Petroleum produces less CO2 emissions than coal during
production. Produces less residue than coal.
• Petroleum is also known as Black Gold - because when
crude oil is extracted from the land it is black in color. People
call it gold because of its oils and value . It is very difficult to
find.
http://www.ei.lehigh.edu/learners/energy/impacts9.html
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4. What is Crude oil and what it contains
• Crude oil is a naturally occurring, unrefined petroleum product
composed of hydrocarbon deposits (liquid and gas) and other
organic materials.
• Color: dark brown, bluish black or black.
•
Crude oil Elemental Composition Hydrocarbons in Crude Oil
Carbon (83-87%) Paraffins (15-60%)
Hydrogen (10-14%) Naphthenes (30-60%)
Sulphur (0.05 -6%) Aromatics (3-30%)
Oxygen (0.05-2%) Asphaltics (Remainder)
Nitrogen (0.1-2%)
Metal (0-1000 ppm)
https://www.thoughtco.com/chemical-composition-of-petroleum-607575
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5. Different Classification of Crude Oil
1. Based on Sulphur Content:
 Sour Crude: Sulphur greater than 5wt% ( Treatment needed)
 Sweet Crude: Sulphur less than 0.5wt%
2. Based on oAPI:
 Light : API >31.1 (Low in aromatic content, High in paraffinic
content)
 Medium: API between 22.3 and 31.1
 Heavy: API < 22.3
 Extra Heavy: API <10.0 (High in aromatic content)
oAPI=
𝟏𝟒𝟏.𝟓
𝐒𝐩𝐞𝐜𝐢𝐟𝐢𝐜 𝐠𝐫𝐚𝐯𝐢𝐭𝐲 𝐨𝐟 𝐜𝐫𝐮𝐝𝐞 𝐨𝐢𝐥 𝐚𝐭 𝟔𝟎𝐨𝐅
− 𝟏𝟑𝟏. 𝟓
http://www.petroleum.co.uk/api
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6. Different Classification of Crude Oil (Contd.)
• Based on Characterization factors:
KW= TB1/3/ G ,
Where, TB is the mean average boiling point, and G is the specific gravity
at 60 oF.
The Watson characterization factor : KW ~15 for highly paraffinic
compounds , KW <10 for highly aromatic materials and KW vary from 10.5
to 12.9. For a highly naphthenic crude it is 10.5 and for a paraffinic base
crude it is 12.9.
• Based on Correlation index:
• CI is useful in evaluating individual fractions from crude oils. The CI scale
is based upon straight-chain paraffins having a CI value of 0 and
benzene having a CI value of 100 and is defined as follows:
C.I = 87552/TB + 473.7 G – 456.8
Low CI  high content of paraffinic HC , High CI  high content of
naphthenic and aromatics
http://nptel.ac.in/courses/103102022/4 6

7. Benchmark Crude Oil
Crude Oil Name API Gravity Specific Gravity Sulphur Content
(wt%)
Arabian Light (Middle
East)
33.8 0.8560 1.8
Brent Crude
(Scotland and
Norway)
38.1 0.835 0.37
Athabasca (Canada) 8 1.0143 4.8
West Texas
Intermediate (USA)
39.6 0.827 0.24
Minas (Sumatran) 35 0.8498 0.08
Bonny Light (Nigeria) 35.4 0.8470 0.14
Tapis Blend
(Malaysia)
45.9 0.7976 0.03
Most Expensive Crude oil
http://www.petroleum.co.uk/benchmarks
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8. Why Refine Crude Oil
1. Removal of unwanted and harmful component from (sulphur,
metal) from crude oil.
2. Convert crude oil into more lighter by products which have a
higher value than crude oil.
3. Production of different petroleum products:
1. Liquefied Petroleum Gas (LPG),
2. Naptha,
3. Gasoline Or Petrol,
4. Jet Fuel,
5. Kerosene,
6. High Speed Diesel,
7. Diesel Oil
8. Fuel Oils.
9. LOBS
10. Bitumen
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9. Flow Diagram of a Typical Petroleum Refinery
https://en.wikipedia.org/wiki/Petroleum_refining_processes
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10. Key Petroleum Processing Unit: Purpose
• ADU: Used for separating lighter compounds from Crude oil such as
LPG, Light Naphtha, Heavy Naphtha, Jet Fuel, Kerosene, Diesel, and
Light gas oil.
• VDU: Used for separating heavier fraction from Crude oil (Reduced
Crude Oil) without decomposing the crude. vacuum gas oil used as
cracker feed.
• Catalytic Cracking: Produce diesel, gasoline and LPG from light and
heavy vacuum gas oil.
• Reforming Unit: Increase octane number of heavy naphtha by
converting straight chain paraffin into cyclic-paraffin or naphthenes.
• Isomerization Unit: Increase octane number by molecular
arrangement of gasoline.
• Visbreaking Unit: Produce LPG, VB naphtha, VBGO from heavy gas oil
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11. Thank You
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