Effect of Ash Melting on the Dielectric Properties and Structure of Coal Chars
Taking Xinjiang bituminous coal as the research object,this paper produced the corresponding coal and coke before and after ash under different working conditions,measured the dielectric performance of coal and coke by using the vector network analyzer,and characterized the microstructure and thermal stability of coal and coke by XRD,FT-IR and thermal weight analysis.The following conclusion is drawn when the coke temperature is below the ash melting point,the presence of ash hinders the development of dielectric properties of coal coke.This is mainly because ash can promote the dissolution reaction of carbon in pyrocoke.Thus destroying the original carbon layer structure.Then,the structure order of raw coal and coal coke is poor,the thermal stability is weak,the graphitization degree is low,and the dielectric performance is weak.When the focusing temperature is above the ash melting point,grey melting can make coal coke have a high dielectric performance.This is because the molten ash attaches to the surface of the coal coke,which can hinder the mass transfer capacity of coal coke,making it difficult to form a developed pore structure.Therefore,the raw coal and coal coke structure has good order,strong thermal stability,high degree of graphitization,and strong dielectric performance.
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