HYDROCARBON FUELS
Most of the fuels that we use contain hydrocarbons. Petrol, Diesel, Kerosene, Liquified Petroleium gas (L.P.G.), Bio gas and Natural gas are some of the hydrocarbon fuels that we use. Most of the energy requirement is fulfilled by these fuels.
Petroleum:
Petroleum is mainly a mixture of several hydrocarbons. It is also referred to as mineral oil or crude of Petroleum is a dark brown liquid. It is found deep below the surface of the earth under the rocks. Petroleum deposits are mined by drilling holes and sinking pipes(Fig) as the pipe reaches the oiil, the oil gushes out through the pipe due to the pressure inside. When the pressure inside reduces, compressed air is passed and oil is pumped out.
Refining of petroleum :
The crude oil is a mixture of components having different boiling points. The process of separating various components of petroleum from one another is known as refining of petroleum. This is done by a process called fractional distillation.
The sand and the water present in the crude oil are separated mechanically. Then the crude oil is washed with dilute sulphuric acid to remove basic impurities and washed with sodium hydroxide solution to remove acidic impurities.
Then the crude oil is sent to the fractioning tower (Fig) through pre-heated pipes.
Crude oil vapourises and rises up in the tower. As the hot vapour rises upwards, different components are cooled down and condense into liquids at compartments of different heights. Components with high boiling point will condense first and they are collected at relatively lower heights where as the components with low boiling points are collected at relatively greater heights.
The uncondensed gases pass out and burn at the top (Fig). The different petroleum fractions obtained in the process are gasoline or petrol, kerosene, diesel oill, fuel oil, lubricating oil, vaseline and paraffin wax.
CRACKING
When heated to a sufficiently high temperature in the absence of oxygen, alkanes decompose to produce hydrocarbons of shorter chain length. This reaction is called thermal cracking or pyrolysis.
For example, when octane is heated to 6500C in the absence of oxygen, it forms ethene and hexane.
Cracking is used to convert some of he less volatile fraction of petroleum containing high molecular mass into compounds of lower molecular masses of higher volatility. Such hydrocarbons with lower molecular masses are more suitable as fuels for automobiles.
The large quantity of unsaturated hydrocarbons produced during cracking of petroleum are the raw materials for the manufacture of polymers and other petrochemical products.
PETROCHEMICALS
Substances obtained from petroleum or natural gas are known as petrochemicals. Petrochemicals are widely used as raw materials in the manufacture of thousands of products like dyes, detergents, polymer, fibers, pesticides, fungicides and many more products including cosmetics. We are using more than 50,000 petrochemical products in various fields.
Remember
The word petroleum is derived from the freek words ‘petro’ which means rock and ‘oleum’ means oil.
NATURAL GAS
Natural gas is the mixture of hydrocarbons found as by-products in the petroleum wells. Natural gas is a mixture of 80% methane, 13% ethane and other hydrocarbons in small quantities. Natural gas is a clean and efficient fuel. The quantity of smoke produced by the combustion of natural gas is negligible. Natural gas is widely used as domestic fuel. It is uded as a substitute petrol and diesel to rum automobiles as compressed natural gas popularly known as CNG. Natural gas is used as a source of heat for industrial boilers. It is also used in the manufacture of formaldehyde, methanol and carbon black.
LIQUIFIED PETROLEUM GAS (LPG)
Liquified petroleum gas is a mixture of several hydrocarbons. Butane is its main component. It is a clean and efficient fuel with high calorific value. Approximately 2900 kJ of heat is liberated by the combustion of one mole of butane (58 g). The gas liquifies under pressure. This makes it easy to store and transport in metal cylinder. LPG is highly combustible. Leakage of LPG is dangerous. A strong smelling chemical, namely, ethyl mercaptan is added which enables the easy detection of leakage.
COMBUSTION PRODUCTS OF HYDROCARBONS
Several gases produced during the combustion of fuels which cause air pollution and hence are harmful. More than 90% of the air pollution is caused by the burning of hydrocarbon fuels only. The gases librated during the combustion are called exhaust gases. Calculation of the quantity of exhaust gases liberated, helps us to know the rate of combustion. It shows whether the combustion is sufficient. Greater proportion of carbon monoxide and carbon particles in the exhaust gas indicates that the combustion is incomplete.
Example:
Let us now study the method of calculating the quantity of carbon monoxide, carbon dioxide and carbon particles produced during combustion of hydrocarbon. Butene is the main component of L.P.G. Let us calculate quantity of pollutants produced by the incomplete combustion of butane.
It is clear that 416g of oxygen is required for the complete combustion of one mole of butane, this is true when 416g of oxygen is available. When the availability of oxygen decreases the combustion is incomplete. Incomplete combustion produces carbon monoxide and carbon particles. The following equation gives details.
If the availability of oxygen for the combustion is 160g. Then along with water (90g.) carbon dioxide (88g) carbon monoxide (28g) and carbon particles (12g) are produced. As the availability of oxygen decreases, the quantity of carbon monoxide and carbon particles will increase. Consequently, there will be decrease in the quantity of carbon dioxide produced. During this incomplete combustion, less heat is produced.
After knowing the amount of exhaust liberated, you cam imagine the pollytion, caused by the burning of fuels. It is enormously high. Therefore, it is important to ensure the complete combustion of fuel when used.
EMISSION TEST
Carbon monoxide released by the automobiles as an exhaust gas, along with other gases, is the most poisonous amont them. About 70-80% of carbon monoxide entering the air is due to automobile exhaust. Even the best of the pertol or diesel engines produces carbon monoxide. Proper maintenance of an engine can be reduce the production of carbon monoxide. For each type of automobiles the limit of carbon monoxide e mission is prescribed by the Government through an act.
Activity Visit an emmission test centre and find out how the percentage of carbon monoxide emitted by the automobile vehicle is estimated.
Discuss with your teacher the harmful effects of carbon monoxide.
Know about different ‘Acts’ passes and rules made by the Government to protect the environment from pollution.
This is different for different types of vehicles. For example, the permitted level of emission of carbon monoxide for cars is 3%. The amount of carbon monoxide released is determined by an instrument called ‘the gas analyser’. The test conducted to determine the percentage of carbon monoxide released by an automobile is called the emission test.
POINTS TO REMEMBER
(1) The electronic configuration of carbon is 1s2 2s2 2p2.
(2) Organic chemistry studies the compounds of carbon
(3) Hydrocarbons are the compounds of carbon and hydrogen only.
(4) The compounds of hydrocarbon exist in straight chain, branched chain and closed chain structures.
(5) Hydrocarbons are classified into aliphatic and aromatic hydrocarbons.
(6) Alphatic hydrocarbons are divided into alkanes, alkenes and alkynes.
(7) The general molecular formula of
alkanes is CnHn+2, example methane,
for alkenes CnH2n, example ethene,
for alkynes CnH2n+2, example elthyne
(8) Benzene and toluene are aromatic hydrocarbons.
(9) Compounds having same molecular formula with different structural formula are known as Isomers.
(10) Hydrocarbon fuels are petrol, diessel, kerosene, liquified petroleum gas (LPG) biogas and natural gas.
(11) Petroleum fractions are petrol, kerosene, gas oil, diesel oil, lubricating oil, vaseline and paraffin wax.
(12) When alkanes are heated to a sufficiently high temperature in the absence of oxygen, they decompose to shorter chain hydrocarbons. Thus reaction is called thermal cracking.
(13) Petrochemicals re chemical substances obtained from petroleum or natural gas.
(14) Liquified Petrolium Gas (LPG) is a mixture of several hydrocarbons.
(15) Compressed Natural Gas (C N G) is used as a substitute for petrol and diesel to run automobiles.
(16) The test conducted to determine the percentage of carbon monoxide released by an automobiles is called the emission test.
Most of the fuels that we use contain hydrocarbons. Petrol, Diesel, Kerosene, Liquified Petroleium gas (L.P.G.), Bio gas and Natural gas are some of the hydrocarbon fuels that we use. Most of the energy requirement is fulfilled by these fuels.
 |
| Petroleum deposits are mined by drilling holes on earth |
Petroleum is mainly a mixture of several hydrocarbons. It is also referred to as mineral oil or crude of Petroleum is a dark brown liquid. It is found deep below the surface of the earth under the rocks. Petroleum deposits are mined by drilling holes and sinking pipes(Fig) as the pipe reaches the oiil, the oil gushes out through the pipe due to the pressure inside. When the pressure inside reduces, compressed air is passed and oil is pumped out.
Refining of petroleum :
The crude oil is a mixture of components having different boiling points. The process of separating various components of petroleum from one another is known as refining of petroleum. This is done by a process called fractional distillation.
The sand and the water present in the crude oil are separated mechanically. Then the crude oil is washed with dilute sulphuric acid to remove basic impurities and washed with sodium hydroxide solution to remove acidic impurities.
Then the crude oil is sent to the fractioning tower (Fig) through pre-heated pipes.
 |
| Refining of Petroleum |
The uncondensed gases pass out and burn at the top (Fig). The different petroleum fractions obtained in the process are gasoline or petrol, kerosene, diesel oill, fuel oil, lubricating oil, vaseline and paraffin wax.
CRACKING
When heated to a sufficiently high temperature in the absence of oxygen, alkanes decompose to produce hydrocarbons of shorter chain length. This reaction is called thermal cracking or pyrolysis.
For example, when octane is heated to 6500C in the absence of oxygen, it forms ethene and hexane.
 |
| Octane heated at 6500C in absence of Oxygen |
 |
| Converts Lower Molecular masses- higher volatility. |
PETROCHEMICALS
Substances obtained from petroleum or natural gas are known as petrochemicals. Petrochemicals are widely used as raw materials in the manufacture of thousands of products like dyes, detergents, polymer, fibers, pesticides, fungicides and many more products including cosmetics. We are using more than 50,000 petrochemical products in various fields.
Remember
The word petroleum is derived from the freek words ‘petro’ which means rock and ‘oleum’ means oil.
NATURAL GAS
Natural gas is the mixture of hydrocarbons found as by-products in the petroleum wells. Natural gas is a mixture of 80% methane, 13% ethane and other hydrocarbons in small quantities. Natural gas is a clean and efficient fuel. The quantity of smoke produced by the combustion of natural gas is negligible. Natural gas is widely used as domestic fuel. It is uded as a substitute petrol and diesel to rum automobiles as compressed natural gas popularly known as CNG. Natural gas is used as a source of heat for industrial boilers. It is also used in the manufacture of formaldehyde, methanol and carbon black.
LIQUIFIED PETROLEUM GAS (LPG)
Liquified petroleum gas is a mixture of several hydrocarbons. Butane is its main component. It is a clean and efficient fuel with high calorific value. Approximately 2900 kJ of heat is liberated by the combustion of one mole of butane (58 g). The gas liquifies under pressure. This makes it easy to store and transport in metal cylinder. LPG is highly combustible. Leakage of LPG is dangerous. A strong smelling chemical, namely, ethyl mercaptan is added which enables the easy detection of leakage.
 |
| L P G Gas Bottle |
Several gases produced during the combustion of fuels which cause air pollution and hence are harmful. More than 90% of the air pollution is caused by the burning of hydrocarbon fuels only. The gases librated during the combustion are called exhaust gases. Calculation of the quantity of exhaust gases liberated, helps us to know the rate of combustion. It shows whether the combustion is sufficient. Greater proportion of carbon monoxide and carbon particles in the exhaust gas indicates that the combustion is incomplete.
Example:
Let us now study the method of calculating the quantity of carbon monoxide, carbon dioxide and carbon particles produced during combustion of hydrocarbon. Butene is the main component of L.P.G. Let us calculate quantity of pollutants produced by the incomplete combustion of butane.
 |
| Calculation of molecular mass of Butane |
 |
| Moles of Butane reacts with Oxygen |
If the availability of oxygen for the combustion is 160g. Then along with water (90g.) carbon dioxide (88g) carbon monoxide (28g) and carbon particles (12g) are produced. As the availability of oxygen decreases, the quantity of carbon monoxide and carbon particles will increase. Consequently, there will be decrease in the quantity of carbon dioxide produced. During this incomplete combustion, less heat is produced.
After knowing the amount of exhaust liberated, you cam imagine the pollytion, caused by the burning of fuels. It is enormously high. Therefore, it is important to ensure the complete combustion of fuel when used.
EMISSION TEST
Carbon monoxide released by the automobiles as an exhaust gas, along with other gases, is the most poisonous amont them. About 70-80% of carbon monoxide entering the air is due to automobile exhaust. Even the best of the pertol or diesel engines produces carbon monoxide. Proper maintenance of an engine can be reduce the production of carbon monoxide. For each type of automobiles the limit of carbon monoxide e mission is prescribed by the Government through an act.
 |
| The Gas Analyger |
Discuss with your teacher the harmful effects of carbon monoxide.
Know about different ‘Acts’ passes and rules made by the Government to protect the environment from pollution.
This is different for different types of vehicles. For example, the permitted level of emission of carbon monoxide for cars is 3%. The amount of carbon monoxide released is determined by an instrument called ‘the gas analyser’. The test conducted to determine the percentage of carbon monoxide released by an automobile is called the emission test.
POINTS TO REMEMBER
(1) The electronic configuration of carbon is 1s2 2s2 2p2.
(2) Organic chemistry studies the compounds of carbon
(3) Hydrocarbons are the compounds of carbon and hydrogen only.
(4) The compounds of hydrocarbon exist in straight chain, branched chain and closed chain structures.
(5) Hydrocarbons are classified into aliphatic and aromatic hydrocarbons.
(6) Alphatic hydrocarbons are divided into alkanes, alkenes and alkynes.
(7) The general molecular formula of
alkanes is CnHn+2, example methane,
for alkenes CnH2n, example ethene,
for alkynes CnH2n+2, example elthyne
(8) Benzene and toluene are aromatic hydrocarbons.
(9) Compounds having same molecular formula with different structural formula are known as Isomers.
(10) Hydrocarbon fuels are petrol, diessel, kerosene, liquified petroleum gas (LPG) biogas and natural gas.
(11) Petroleum fractions are petrol, kerosene, gas oil, diesel oil, lubricating oil, vaseline and paraffin wax.
(12) When alkanes are heated to a sufficiently high temperature in the absence of oxygen, they decompose to shorter chain hydrocarbons. Thus reaction is called thermal cracking.
(13) Petrochemicals re chemical substances obtained from petroleum or natural gas.
(14) Liquified Petrolium Gas (LPG) is a mixture of several hydrocarbons.
 |
| Compressed Natural Gas Connection Car |
(16) The test conducted to determine the percentage of carbon monoxide released by an automobiles is called the emission test.
(17) The instrument used for emission test is called the gas analyser.
Thanks to google image provider.
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