What are the requirements for coal in lime kiln shaft kiln
As the core equipment for lime production, the lime kiln has strict requirements for coal quality. Among them, smokeless coal with high calorific value and low volatile matter has become an ideal fuel for vertical kiln calcination of lime due to its unique physical and chemical properties.
Anthracite is the coal with the deepest coalification degree, with a high carbon content, usually above 90%, low ash and moisture content, and extremely high heat generation, reaching 25000-32500 kJ/kg or even higher. This high calorific value characteristic allows it to release a large amount of heat during combustion, providing sufficient energy for the calcination of limestone, ensuring a stable calcination temperature of 1100-1200 ℃, and meeting the thermodynamic conditions for the decomposition of limestone to produce calcium oxide.
Meanwhile, the volatile content of anthracite is extremely low, generally not exceeding 10%. Volatile matter is a gaseous substance released by coal during the heating process, and its content directly affects the ignition and combustion stability of coal. Due to its low volatile matter, smokeless coal burns with a bluish blue flame, and the coke has no adhesiveness, making it less prone to coking. This can effectively prevent excessive burning or agglomeration of lime caused by local high temperatures in the shaft kiln, ensuring uniform and stable lime quality.
Anthracite also has the characteristics of high ash melting point and good thermal stability. It is not easy to soften and melt during high-temperature calcination, which can reduce ash accumulation and blockage in the kiln, extend the service life of the kiln, and reduce maintenance costs. Therefore, selecting anthracite with high calorific value and low volatile matter for lime kiln shaft kiln is the key to achieving efficient, stable, and high-quality lime production.
