Transcript Crude Oil Refining & Upgrading

Crude Oil Refining &
Upgrading
By: Kelvin Wong, Kaying Ng,
Shaheen Zangooi
What is Crude Oil & Crude Oil Refining?
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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
Distillation of Crude Oil
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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
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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)
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Petrochemical Product: A crude oil fraction which contain one or two
specific hydrocarbons of high purity (e.g. benzene, toluene, and
ethylene).
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
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
11 to 18
200 to 300
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.
Chemical Processing
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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
Treatment Processes
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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.
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Clay Treating
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Dilute the oil with solvent and freeze the oil
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During the freezing process, wax will be solidify leaving only the pure oil
in liquid phase
Acid treating
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Use clay to soak up and remove unwanted components in petroleum
Using concentrated sulphuric acid to convert sludge from the oil
Expensive
SO2 Treating
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Using a very toxic recyclable solvent to remove the worst components in
oil
Treatment: The Finishing Touch
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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
Refining Capacities
Why Upgrade An Oil Refinery?
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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
Accomplishment of Oil Refinery
Upgrading
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The emissions of
pollutants from oil
refining decreased
significantly over the
past decade due to
the new technology
implemented into the
oil refining
techniques
Solvent-Refining Process
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Uses chemicals (fairly safe recyclable solvent) to dissolve one part of the oil
from another
Removes heavy materials and wax (undesirable component by extraction)
References
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How Stuff Works. 1998. How Oil Refining Works?. [Online].
http://science.howstuffworks.com/oil-refining.htm
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UTS Energy Corporation. 2005. Glossary. [Online]
http://www.uts.ca/glossary/
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www.gcsescience.com. 2005. Products of Oil. [Online]
http://www.gcsescience.com/a/o5.htm
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Alan G. Lucas. 2000. Modern Petroleum Technology Volume 2. New York:
John Wiley & Sons Inc.
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Douglas M. Ruthren. 1997. Encyclopaedia of Separation Technology
Volume 2. New York: John Wiley & Sons Inc.