properties and uses of bituminous coal
Properties and Uses of Bituminous Coal
Bituminous coal is the most common type coal used in the world for a variety of purposes. Read on this Buzzle artcle to learn about the uses and properties of the coal.
- Soft and completely opaque
- Dark gray to black in color, and is banded, or layered.
- Has moisture content of about 2 to 17%.
- Carbon content of about 45 to 85%
- Ash content is about 2 to 14% and contains 0.5 to 2 percent nitrogen.
- Sulfur of about 0.5 to 5 % and chlorine of about 340 ± ppm.
- Closely-spaced fractures called cleats are usually found in bituminous coals. Cleats form in two sets at right angles to one another.
- Bituminous coals are highly combustible and releases excessive smoke and soot if not burned properly. The main pollutants from bituminous coal are particulate matter (PM), sulfur oxides, and nitrogen oxides. Some metals like lead and mercury, hydrocarbons like methane, alkanes, alkenes, benzenes, and others are also released. Some unburned substances like carbon monoxide and various organic compounds are released even under proper boiler operating conditions.
- The sulfur that is present in high degree in the coal brings acid rain.
- Coals have heating values of 10,000 to about 15,000 British thermal units per pound (Btu/lb), which is much higher than that of lignite or sub-bituminous coal.
- They have lower fixed carbon and higher volatile content than that of anthracite.
- Bituminous coals have two subtypes; thermal or steam coal and metallurgical coal. Metallurgical or coking coal is baked in ovens in the absence of oxygen at temperatures as high as 1,100 °C (2010°F). This process is callled pyrolysis. By this process, the coal is melted and the volatile constituents and impurities are driven off. Finally, the end product is pure liquified carbon which solidifies into coke.
- Mostly, bituminous coal contains a glassy material called vitrinite. It is composed of macerals, which comes from woody plant tissue.
- Used to fire power plants that produce steam for the generation of electricity.
- As a fuel to produce steam that runs locomotive trains. They were also previously used as a fuel for domestic water heating.
- Metallurgical coal or coking coal has high resistance to heat and is used to create coke, which is added to the blast furnace with iron ore and limestone to produce steel. So, this is an essential product of the iron and steel industries.
- Bituminous coal is made free from ash, sulfur, and other impurities, and used in coal forges, where metals are heated and shaped.