Coal Energy is one of the types of fossil fuels and non-renewable energy. Fossil fuels like coal, oil and gas are present in the earth’s crust in fixed quantities and as an inexhaustible source of energy. Coal is present in the earth in many forms. Some forms of the coal are of better qualities than the other. Coal is an essential combustion material which is usually black or brown in color.
Types of Coal and Uses of Coal
The coal is present in the earth’s layer due to the decay of plants in the water centuries ago. The coal is composed of carbon, sulfur, hydrogen, nitrogen and oxygen. The important types of coal are Paet, Lignite, sub-bituminous coal, bituminous coal, Anthracite and graphite. The pressure over the dead biotics and plants present in the earth layer for centuries have converted it into Paet. This form of coal is considered an ancestor to the current coal and it is used in industry as fuel. This fuel is used in dehydrated form to absorb the spilling of fuel from land or from water. Lignite is a poor quality coal and is burnt to provide thermal energy for heating steam turbines in order to produce electricity. This coal was used in train engines for centuries till the invention of modern engines Lignite is brown in color. Sub-bituminous and bituminous are black in color and are also used to run steam turbines for producing electricity. Anthracite is the shiny black coal of really good quality. This type of coal is used in homes for space heating procedures. Graphite is the best type of coal in terms of quality. However this type of coal is difficult to burn hence it is used in pencils and as a lubricant in powdered form. The coal liquefaction can replace the use of oil. China is making use of this technology as the need for liquid oil is increasing in transportation sector.
Energy Contained in Coal
The energy contained in coal is dependent upon the conversion of potential energy present in the coal to heating capability. The heat content of Anthracite is 35300 KJ/kg. This is the best type of burning coal. Lignite on the other hand has heat content of about 28470KJ/KG. The energy content and quality of the coal is dependent upon the content of carbon contained in it. Anthracite contains 91% carbon along with other volatiles this gives it more strength while burning. Carbon is the main component of coal. Generally speaking the energy value of coal is 24MJ/KG besides its different forms. It requires 966 pounds of energy is required to burn a bulb of 100 watts. When the coal is converted to electricity the energy from the coal is then calculated in the form of kilowatt per hour.
Disadvantages of Using Coal
Coal is oldest technique to run steam turbines for producing electricity. Coal is composed of many types of gases, like carbon, nitrogen and hydrogen. The major disadvantages of coal energy when it is burnt it releases harmful gases in the air. The presence of these harmful gases along with the waste of industrial processes has resulted in immense global warming. The coal which contains high content of sulfur results in acidic rain. The burning of coal results in flue gas, fly ash and bottom ash which contain thorium, mercury and other metals. Among all the non-renewable energy sources this is the highest pollution producing fuel. The emission of gases and material into the air and water causes many dreadful diseases like dust nuisance, lung cancer and influenza. The process of coal burning generates many greenhouse gases like carbon dioxide which have resulted in the destruction of ozone layer and global warming.