Types of Coal
Not all coal is alike. As you can see from the pictures they all look very differently and also burn differently. The source and the formation of the coal directly controls the qualities of the coal. A mines location determines the type of coal produced. This is based on the geological history of the area and how the coal was formed back in history. The ancient accumulation of plant material combined with other material deposited over it creating pressure to change it into rock that can be burned.
Formation of Coal
It is possibly very hard to imagine how different our world was 600 to 300 Million years ago. Back in the period that coal is formed from was dominated by plant live and very little animal life. The other factors were a higher oxygen content in the atmosphere along with a much moister environment. Based on these factors being in place it is not that hard to visualize lush and plentiful plant growth. So in some areas large accumulations of plant material would accumulate on the ground and create bogs were the material was covered by water or other plant material and did not completely break down. With geological changes other materials were deposited on top of these bogs and with depth and pressure turned to rock. The pressure dries the material compacted it and eventually turned it to Coal a flammable rock. Due to the way coal is formed it tends to be in veins and stratified. Various conditions created various qualities of coal deposits that are now mined for energy.
Graphite is a higher grade of coal and is considered to be the highest grade of coal. It is ranked above anthracite coal. Graphite is not normally thought of coal since it very difficult to ignite and not used as a fuel.
Is the highest in energy content and lowest in impurities of the coals that are burned. Anthracite coal is a sedimentary rock that is the hardest coal and a glossy black color. Due to the energy content and reduced impurities Anthracite coal is used primarily for home heating and commercial space heating. The subcategory of Pennsylvania Anthracite is called petrified oil, as from the deposits in Pennsylvania that we sell. Anthracite coal has between 91% and 98% carbon content.
Bituminous coal is called black coal and is not as hard as Anthracite coal. It contains deposits of bitumen that is a tar like substance so this makes it softer. This coal comes from lignite coal that has been under more pressure for longer periods of time. Their are higher amounts of water, air, hydrogen and sulfur contained in this coal so the carbon content is lower and more gases are given off in combustion. The large difference in carbon content is reflected in the fact that the percentage of carbon content in bituminous coal is around 60-80%.
This is a more variable coal than Bituminous has a higher moisture content and is subject to spontaneous combustion. It should be packed densely in storage to prevent air flow through the pile thus preventing the spontaneous combustion. At plants that use this coal compaction is achieved by using rubber tired dozers to kneed the coal pieces packed together to prevent air flow.
Is a brown colored coal that is a soft fuel with characteristics that put it somewhere between coal and peat. This coal has a carbon content of has a carbon content of around 25-35%. The carbon content is an indicator or its purity for fuel. Having a high moisture content of brown coal, carbon dioxide emissions from brown coal fired plants are generally much higher than for comparable black coal plants. This is clearly not a home heating type of coal.
Burning Anthracite Coal
As the pictures show these different types of coal are distinctly different,so when considering heating with coal and the image of smokey industustrial stacks come to mind that is not from burning Anthracice coal. Antharcite coal once it has been light burns as clean or cleaner than propane. This is why coal stoves can be set up as through the wall chimneyless installations. See for yourself, take a look below at our fair display of a coal stove burning and then going around to the back to see the top of the chimney.
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