1. Crude Oil Refining & Upgrading
By: Kelvin Wong, Kaying Ng, Shaheen Zangooi

2. What is Crude Oil & Crude Oil Refining?
Crude oil, also known as black gold, is a thick, dark brown or greenish flammable liquid, which is found in the upper strata of some regions of the Earth's crust
It is a complex mixture of various hydrocarbons, (mainly, alkanes), along with trances of other chemicals and compounds (e.g. Sulphur)
When extracted from underground, it ranges in density from very light to very heavy and in color, from yellow to black
Crude oil can be categorized as either "sweet crude" (where the sulphur content less than 0.5%) or "sour crude," (where the sulphur content is at least 2.5%)
Crude oil must undergo several separation processes so that its components can be obtained and used as fuels or converted to more valuable products
The process of transforming crude oil into finished petroleum products (that the market demands) is called crude oil refining
An Oil Refinery

3. Distillation of Crude Oil
We can separate the components of crude oil by taking advantage of the differences in their boiling points. This is done by simply heating up crude oil, allowing it to vaporize, and then letting the vapor to condense at different levels of the distillation tower (depending on their boiling points). This process is called fractional distillation and the products of the fractional distillation of crude oil is called fractions
A fraction from crude oil can be categorized into two categories:
Refined Product: A crude oil fraction which contains a lot of individual hydrocarbons (e.g. gasoline, asphalt, waxes, and lubricants)
Petrochemical Product: A crude oil fraction which contain one or two specific hydrocarbons of high purity (e.g. benzene, toluene, and ethylene).

4. AT THE BOTTOM OF THE DISTILLATION COLUMN
Crude Oil Refining
AT THE TOP OF THE DISTILLATION COLUMN
AT THE BOTTOM OF THE DISTILLATION COLUMN
Short carbon chains
Long carbon chains
Light molecules
Heavy molecules
Low boiling points
High boiling points
Gases & very runny liquids
Thick, viscous liquids
Very volatile
Low volatility
Light colour
Dark colour
Highly flammable
Not very flammable

5. Fractions of Crude Oil & Their Properties
Name
Number of Carbon Atoms
Boiling Point (°C)
Uses
Refinery Gas
3 or 4
below 30
Bottled Gas (propane or butane).
Gasoline
7 to 9
100 to 150
Fuel for car engines.
Naphtha
6 to 11
70 to 200
Solvents and used in gasoline.
Kerosene (paraffin)
11 to 18
200 to 300
Fuel for aircraft and stoves.
Diesel Oil
Fuel for road vehicles and trains.
Lubricating Oil
18 to 25
300 to 400
Lubricant for engines and machines.
Fuel Oil
20 to 27
350 to 450
Fuel for ships and heating.
Greases and Wax
25 to 30
400 to 500
Lubricants and candles.
Bitumen
above 35
above 500
Road surface and roofing.

6. Chemical Processing
The fractions from crude oil are liable to undergo chemical processing to alter its structure and thus its properties
The sort of chemical processing employed depends largely on the market demand
Examples of chemical processes are as the following:
Cracking: the process obtaining relatively simple and small hydrocarbon molecules from the breaking down of large, heavier and more complex hydrocarbon molecules.
Coking: the process of breaking down bitumen into its fractions (done by a Coker)
Alkylation: A process where the structure of a hydrocarbon molecule in one fraction is altered to produce another hydrocarbon molecule with another structure. In alkylation, compounds with a low molecular weight, such as propylene and butylene, are mixed in the presence of a catalyst such as hydrofluoric acid or sulfuric acid
Unification: a process where two or more hydrocarbons are combined to produce a larger one. The major unification process is called catalytic reforming and occurs in the presence of a catalyst (platinum, platinum-rhenium mix) to combine low weight naphtha into aromatics

7. Treatment Processes
Chemical sweetening, acid treating, clay contacting, caustic washing, hydro treating, drying, solvent extraction, and solvent dewaxing. Sweetening compounds and acids desulphurize crude oil before processing and treat products during and after processing.
Clay Treating
Use clay to soak up and remove unwanted components in petroleum
Dilute the oil with solvent and freeze the oil
During the freezing process, wax will be solidify leaving only the pure oil in liquid phase
Acid treating
Using concentrated sulphuric acid to convert sludge from the oil
Expensive
SO2 Treating
Using a very toxic recyclable solvent to remove the worst components in oil

8. Treatment: The Finishing Touch
Impurities such as organic compounds containing sulphur, nitrogen, oxygen, water, dissolved metals and inorganic salts must be removed from the distillated and chemically processed fractions
Treating is typically done by passing the fractions through the following:
a column of sulphuric acid - removes unsaturated hydrocarbons (hydrocarbons with carbon-carbon double-bonds), nitrogen compounds, oxygen compounds and residual solids (tars, asphalt)
an absorption column filled with drying agents to dehydrate the fraction
sulphur treatment and hydrogen-sulphide scrubbers to remove sulphur and sulphur compounds
Today, a major portion of refining involves blending, purifying, fine-tuning and improving products to meet specific requirements
Example: Refinery workers carefully blend together a variety of hydrocarbons to make  petrol. Moreover to distinguish the various grades of fuel, technicians add performance additives and dyes. At the end of the production of petrol, the petrol contains more than 200 hydrocarbons and additives

9. Refining Capacities

10. Why Upgrade An Oil Refinery?
Oil refining releases carbon dioxide into the atmosphere
Response to changing market demands for certain products
Government regulations
Clean Air Act Amendments of 1990 (CAAA90)
Changing consumer demand for better and different products
Decrease the number of non-hydrocarbons, impurities, and other constituents
Potential physical, mechanical, chemical, and health hazards are recognized in air

11. Accomplishment of Oil Refinery Upgrading
The emissions of pollutants from oil refining decreased significantly over the past decade due to the new technology implemented into the oil refining techniques

12. Solvent-Refining Process
Uses chemicals (fairly safe recyclable solvent) to dissolve one part of the oil from another
Removes heavy materials and wax (undesirable component by extraction)

13. References
How Stuff Works How Oil Refining Works?. [Online].
UTS Energy Corporation Glossary. [Online]
Products of Oil. [Online]
Alan G. Lucas Modern Petroleum Technology Volume 2. New York: John Wiley & Sons Inc.
Douglas M. Ruthren Encyclopaedia of Separation Technology Volume 2. New York: John Wiley & Sons Inc.