Coal Classification
Coal classification is a process that classifies the different types of coal into different categories based on their characteristics. It is a process that is commonly used in order to differentiate and distinguish between the different grades of coal produced in different geographical regions. Classification of coal is important because it helps in understanding the different types of coal and their properties.
Coal classification is mainly based on four factors: vitrinite content, carbonaceous content, ash content, and moisture. These four factors enable us to classify the coal into different categories that can be used for various purposes.
The use of vitrinite content as a factor for coal classification is mainly due to the fact that vitrinite is the main organic component of coal and the properties of coal are mainly based on the properties of vitrinite. Vitrinite helps determine the coal rank, which is classified into a number of different ranks. The highest ranked coal is anthracite, followed by bituminous and then sub-bituminous and lignite. Anthracite has a vitrinite content of more than 80 percent and can be used in the manufacture of steel. Bituminous coal has high amounts of volatile material and therefore produces a high amount of energy when combusted. Sub-bituminous coal has a lower heating value and less volatile material and is mainly used in the steam-electric power industry. Lignite has the lowest heating value and is mainly used as a soil conditioner.
The carbonaceous content of coal is also an important factor in classification. This is because of the fact that it affects the energy content, ignition temperature, and ash content of coal. It usually ranges from 50-85 percent and is one of the major factors in determining the rank of coal.
The ash content of coal helps determine the caking properties, permeability to gas, and other qualities of coal. The amount of ash in coal is usually 0-4 percent for anthracite, 4-8 percent for bituminous coal, 10-15 percent for sub-bituminous, and more than 15 percent for lignite.
Finally, moisture content is also necessary in classifying coal. For classification purposes, it is usually determined as free moisture, that is, the amount of water present in the coal when freshly mined. It is usually between 25-30 percent for anthracite and 15-25 percent for bituminous coal.
In conclusion, coal classification is a process that is necessary in order to understand and categorize the different types of coal produced in different regions. The four factors used for coal classification – vitrinite content, carbonaceous content, ash content, and moisture content – help differentiate and rank the different types of coal. The rank of coal helps determine the properties, melting points, and other useful qualities of coal.
