Oil Shales – Where Did Shales Form?
Shales formed in closed bodies of calm water, where microscopic plant and animal organisms underwent profound changes in the absence of dissolved oxygen. Pelogen settled to the bottom of the reservoirs as a clump-like mass, which over time transformed into organic matter.
Shale, with its high calorific value of combustible matter—up to 34.8 MJ/kg (8,300 kcal/kg)—is one of the lowest-grade fuels due to its high ash content and significant moisture content. Its Q is typically 6.3–9.66 MJ/kg (1,500–2,300 kcal/kg).
Therefore, it is generally used as fuel only if burned at the mine site, without significant transportation.
The high hydrogen content and volatile matter yield of up to 80% per hot mass make it possible to utilize oil shale as a raw material for gasification, as well as for chemical processing to produce various types of oils, motor fuels, chemical products, and combustible gas. The composition of the working mass of oil shale is approximately as follows: carbon C = 24.4%; hydrogen 3.1%; oxygen O = 3.7%; nitrogen N = 0.1%; volatile matter yield Vd = 80-90%; ash content AJ = 40%; moisture content W = 13%.
Ash melting point is 1150-1450°C.
