Alacsonyszénfajták

Alacsonyszénfajták, or low-rank coals, refer to types of coal with a relatively low carbon content and a high moisture and volatile matter percentage. These classifications typically include lignite and sub-bituminous coal. Lignite, also known as brown coal, is the youngest form of coal, characterized by its high moisture content (often exceeding 30%) and low heating value. It is softer, more fragile, and has a dull brown to black appearance. Sub-bituminous coal is slightly more mature than lignite, with a lower moisture content and a higher heating value, though still inferior to higher-rank coals like bituminous and anthracite. Its carbon content is generally between 45% and 76% on a dry, ash-free basis.

The formation of alacsonyszénfajták occurs from peat under moderate geological pressure and temperature. Due to their lower energy density and higher ash and moisture content, they are often less desirable for direct combustion compared to higher-rank coals. Their transportation is also less economical over long distances. Consequently, low-rank coals are frequently utilized in power plants located in close proximity to the mining sites. Environmental concerns associated with their use include higher emissions of sulfur dioxide and greenhouse gases per unit of energy produced, necessitating advanced pollution control technologies. Despite these drawbacks, their abundance in certain regions makes them a significant energy resource.