What is the composition of coal
. Sulfur, phosphorus, fluorine, chlorine and arsenic are harmful components in coal. When most of the coal burning sulfur is oxidized to sulfur dioxide (SO2), with the flue gas emissions, air pollution, harm to animal and plant growth and human health, corrosion of metal equipment; when the multi sulfur coal for metallurgical coke, but also affect the quality of coke and steel. So, the sulfur content is one of the important evaluation index of coal. The organic matter in coal at a certain temperature and under the condition of combustible gas produced by thermal decomposition, called "Volatile", it is a mixture composed of various hydrocarbons, hydrogen, carbon monoxide and other compounds
Su. Carbon, hydrogen and oxygen are the main components of coal organic matter, accounting for more than 95%; the higher the degree of coalification, the higher the carbon content, the lower the content of hydrogen and oxygen. Carbon and hydrogen are the elements that produce heat in the process of coal combustion. In the process of coal combustion, nitrogen does not produce heat, and is converted to nitrogen oxides and ammonia at high temperature.
Volatile matter is also the main coal quality index, in determining the processing and utilization of coal processing and process conditions, volatile matter has an important reference. Coal with low coalification degree, more volatile. If the combustion conditions are not appropriate, high volatile coal combustion is easy to produce unburned carbon particles, commonly known as "black smoke" and produce more carbon monoxide, polycyclic aromatic hydrocarbons, aldehydes and other pollutants, thermal efficiency decreased. Therefore, the appropriate combustion conditions and equipment should be selected according to the volatile components of coal. The content of inorganic matter in coal is very little, which mainly includes water and minerals. Minerals are the main impurities in coal, such as sulfides, sulfates, carbonates, etc., most of which are harmful.
Water has a great influence on the processing and utilization of coal. When water is burned, it changes into steam to absorb heat, thus reducing the calorific value of coal. The moisture in coal can be divided into external and internal moisture, generally in the water as the index of evaluating coal quality. The lower the degree of coalification, the larger the surface area of coal, the higher the moisture content. "Ash" is the solid residue remaining after complete combustion of coal, is an important quality index. Ash mainly comes from non combustible minerals in coal. Mineral combustion to absorb heat, a lot of slag to take away the heat, so the higher ash content, the thermal efficiency of coal combustion is lower; the more the more ash, ash from coal combustion, fly ash emissions more. Generally, the ash content of high quality coal and washed coal is relatively low.
