Solid fuels are a large category of fuels, solid combustible substances that produce heat or power, mostly containing carbon or hydrocarbons. The natural ones are wood, peat, lignite, bituminous coal, anthracite, oil shale, etc. The processed ones are charcoal, coke, briquettes, briquettes, etc. There are also some special varieties, such as solid alcohol and solid rocket fuel. Compared with liquid or gaseous fuels, solid fuels in general are harder to control in combustion, less efficient and have more ash.
Solid fuels include the following types.
1.Bituminous coal: known as long bituminous coal, gray-black or black, the surface is lusterless or has an oily luster.
2.Anthracite coal: called white coal or wood coal, black, sometimes gray, hard and brittle, with a lustrous cross-section.
3.Poor coal: between bituminous coal and anthracite, volatile to 10%-20%, easier to catch fire
4.Coal gangue: it is the coal seam with combustible quality of the sandwich stone, ash is high, reaching more than 50%, the heat is low, not suitable for fire.
5.Oil mother shale: it is a kind of ore containing oil, ash is very high, reaching 50%-70%, volatilization is also very high, reaching 80%-90%, it is easy to catch fire.
6.Firewood: It has less ash and high volatile content than coal, and burns quickly, but has low heat generation.
