Coal, which is the byproduct of ancient Plant fossils, was once the most important source of energy in the global world. After the invention of electricity and oil, coal has been replaced for most uses. However, it is still used for power generation, especially in countries such as China, India and Australia.
From a chemical point of view, coal is a heterogeneous material that includes several chemical elements such as carbon, hydrogen, oxygen, nitrogen and sulfur. The combination of these elements determine the reactivity and composition of coal, which directly affects its use. The reactivity of coal is best represented by its heating value, which evaluates the amount of energy that can be released when it is burned. There is a wide range of coal sources that demonstrate different reactivity levels depending on the organic material preserved in them.
In terms of reactivity, coal is divided into three main categories: Anthracite, Bituminous, and Lignite. Anthracite is the most reactive type of coal, and it is primarily composed of carbon. Anthracite provides a high heat energy per unit of weight, and it is often used for power generation in large scale power plants. Bituminous is a softer type of coal and it contains both carbon and hydrogen. This type of coal has moderate reactivity, and it is often used for residential heating and industrial applications. Lignite is the least reactive type of coal and it consists of high moisture content and a lower carbon content than other types of coal. This type of coal is less commonly used because of its low heating value.
In terms of specific reactivity measures, the coal rank is often referred to. Coal rank is a classification that is used to differentiate coal according to their heating values. This classification is based on the percentages of fixed carbon, volatiles, and ash present in coal. The higher the fixed carbon content in coal, the higher its rank, whereas the lower the rank, the lower the heating value.
The reactivity of coal is also determined and influenced by other factors, such as the grain structure of coal, the mineral composition and the mineralogy of the coal source, the presence of volatile and non-volatile compounds, and the size of the coal grains. All these factors can change the reactivity of coal and its use. For example, the presence of minerals such as iron, magnesium, calcium and silicon are known to increase the reactivity of coal.
The reactivity of coal also applies to its use for combustion. The combustion of coal occurs in three stages: ignition, burning, and burnout. The reactivity of coal determines the speed in which the coal burns and the amount of energy that can be released during the combustion. In general, the more reactive a coal is, the faster the combustion process is, and the higher the amount of energy that can be released. The reactivity of coal also influences the amount of pollutants that are released during combustion and the efficiency of the process.
In conclusion, the reactivity of coal is determined by its chemical composition and the presence of minerals. The reactivity of coal directly affects its use and the amount of energy that can be released when it is burned. It is important to understand the reactivity of coal in order to properly utilize it and reduce the environmental impact of its use.
