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Crude Oil

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aishah akhtar

on 2 March 2014

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Transcript of Crude Oil

Combustion
Of alkanes
Crude Oil
Fact:
Right now, the world consumes about 89 million barrels of oil per day.

Hydrocarbons & there boiling points
Fractional distillation
Biofuels
Cracking
Pollution & Global Warming
Boiling is a physical change whereby a liquid is converted in to a gas.
Burning Hydrocarbons increases atmospheric pollutants:


Fractional distillation is a process used to separate crude oil into different substances at different boiling points.

Are fuels that derive from recently living materials such as plants. They are
renewable
, fast and easy to produce and can be relatively
cheap
. we need these types of fuels as our current resources are depleting rapidly.
such as; Sugar can, Ethanol: (made from fermentation) and biodiesel.
Citi recently predicted that world
oil demand
may peak by during the next few years because of increased transport efficiency among other factors.
How was it formed?
FROM ORGANISMS WHICH LIVED MILLIONS OF YEARS AGO

THEIR REMAINS WERE COVERED BY LAYERS OF SEDIMENTARY ROCK

HEAT AND PRESSURE IN THE ABSENCE OF AIR CONVERTED THE REMAINS INTO FOSSIL FUELS

LARGE HYDROCARBONS ARE VAPORISED (TURNED INTO GAS)
THE VAPOR IS THEN PASSED OVER A HOT CATALYST
BONDS ARE BROKEN AND SMALLER MOLECULES ARE MADE

Van der Waals’ forces
Weak intermolecular forces that must be broken for a liquid to boil.
As the chain length increases there are more points of contact between the molecules leading to more Van der Waals’ forces.
It therefore takes more energy (higher temp) to overcome these forces.

Effect of branching
There are fewer points of contact between molecules, therefore fewer Van der Waals’ forces.
Branched isomer will have a lower boiling point than the unbranched isomer.

When the mixture is heated, liquids with a low boiling point evaporate and turn to vapour.

Liquids with a higher boiling point remain as liquid. The vapour can then be separated from the liquid.

-
short chained alkanes are valuable as clean fuels
- they burn in plentiful supply of oxygen
- Methane is a main constituent, used for domestic heating and cooking.

Incomplete combustion.....
Incomplete combustion.
General theory.....
Incomplete combustion of alkanes can lead to potential dangers.
- combustion in engines can have a limited supply of O .
- CO's is produced (clear, colourless gas)
- Prevents haemoglobin binding to oxygen, straving tissues of oxygen.
- CO can be formed from faulty heating systems, blocked chimneys, or inadequate ventilation.
2
Crude oil is not very useful in its native state as it does not ignite easily.
However, individually, the components of crude oil have a variety of uses...if they can be separated out!

Long

chained

hydrocarbons
Shorter
chain alkanes
Shorter
chain alkenes
these are used in polymer production
these chains are used as fuels
Cracking process uses:
- a
zeolite catalyst
and does not require a high temperature or pressure to produce different lengths of alkanes and alkenes. However, the yield of alkanes produced is higher than alkenes produced.
-
thermal cracking
, high temperatures (typically in the range of 450°C to 750°C) and pressures (up to about 70 atmospheres) are used to break the large hydrocarbons into smaller ones. Thermal cracking gives a higher yield of alkenes than alkanes.
Petrol blending is when petrol companies change the alkanes they use in petrol for each season to obtain the correct properties. e.g. volatility, octane number and efficiency it burns.

Summer Fuel:

Longer molecules
Less volatile
Evaporates more likely when warm

Winter Fuel

Shorter molecules
More volatile
Evaporation needs to happen more easily




Petrol blending
ISSUES OF PETROL BLENDING
Economic impact: the higher octane numbers are more expensive when required in Summer.
Global impact: catalytic converters allow impurities in the engine of a car to be converted from carbon monoxide to carbon dioxide. Although Carbon dioxide is less harmful to humans, it impacts global warming.
The petroleum industry processes straight chain hydrocarbons into branched alkanes & cyclic hydrocarbons to promote efficient combustion.
~ Isomerisation used to produce branched or cyclic alkanes
~ Branched and cyclic alkanes burn more efficiently.
Ethanol:
- combusts efficiently in a plentiful supply of O2.
- can be mixed with petroleum leading to a further efficiency
- used as Bio ethanol in UK, 105,000 tonnes produced yearly.

Biodiesel:
Produced from Rapeseed crops
- 100% pure, although is usually mixed with normal diesel for extra efficiency.
+
CO
- toxic, formed by incomplete combustion
+
CO2
- contributes to global warming via greenhouse effect
+
NO2
- avid rain and destruction of forests
+
SO2
- acid rain
Greenhouse gases prevent heat escaping the atmosphere, leading to global temperature rise.
> heavier rainfall/storms/melting of ice-caps
>causes sea level rise - affecting lifestyles.
Thank you for Watching .
Citi recently predicted that the world
oil demand

may peak during the next few years because of increased transport efficiency and other factors.
Full transcript