Coal injection pulverizing process refers to the preparation process of pulverized coal injection into the blast furnace. It is a technical measure for iron and steel plants to inject fuel into the blast furnace during ironmaking. The whole pulverized coal preparation process of the blast furnace coal injection workshop is mainly composed of raw coal storage and transportation, pulverized coal preparation, pulverized coal transportation, pulverized coal injection, dry gas preparation and air supply power system. At present, the equipment commonly used in the blast furnace coal injection pulverizing system is the coal vertical roller mill, also known as the medium speed grinding mill.
It is a pulverized coal preparation system combining drying and pulverizing, which can realize drying while grinding. It is applicable to anthracite, bituminous coal, lignite, and semicarbon. The fineness of pulverized coal can be adjusted. Generally, the coal fineness of coal injection pulverizing process is required to be 200 meshes.Here we will learn about the pulverizing process and equipment of the pulverized coal preparation system in the lower coal injection workshop.
Pulverizing process flow of coal injection workshop: raw coal is sieved by lattice screen from raw coal storage yard and then falls onto large inclined belt conveyor or elevator. After iron is removed by electromagnetic iron remover, the belt conveyor or elevator sends raw coal to raw coal bunker for storage. After the pulverizing system has been started, open the rod valve at the bottom of the raw coal bunker, start the sealed metering belt coal feeder, and the raw coal will enter the pulverized coal vertical mill for drying and grinding. The hot air or waste gas from the hot air furnace is pumped by the system fan into the coal vertical roller mill. After full heat exchange with the raw coal being ground in the mill, the pulverized coal is picked up and sorted at the separator. The coarse pulverized coal with unqualified fineness falls onto the grinding plate again for grinding. The qualified pulverized coal enters the explosion-proof air box pulse dust collector with the air flow and is collected. It is unloaded into the pulverized coal bin through the grid wheel. The sundries in raw coal, such as some gangue and metal blocks, are discharged from the mill through the air ring and slag discharge port. As pulverized coal is a combustible and explosive material, Our pulverized coal preparation system adopts nitrogen inerting technology and Class V explosion-proof equipment in the process of mixed coal grinding, which is safe and reliable in the process of pulverized coal processing, and is also a very important link in the process of pulverized coal processing. In the whole process, there is a carbon monoxide oxygen online analysis system. When processing coal with high volatile content, nitrogen protection and CO2 automatic fire extinguishing system and other safety measures can be set.