Coal pulverizing in power stations
Pulverizing coal consists in grinding coal as fine as possible prior to combustion in the steam-generating furnaces of fossil fuel power plants. Coal pulverization is essential to the overall system process of a coal-fired power station, not just in terms of furnace performance and heat rate but in terms of the mechanical reliability and integrity of the furnace. Pulverizer performance plays a key role in back-end emissions in terms of particulate loading.
Pulverizing coal is viewed as a high wear process and generally considered the “key” to combustion performance; thus the primary consideration of many when it comes to optimizing system performance. Vertical Mills (VM) are the predominant design for coal pulverization and are designed to achieve a specific performance (discharge fineness and capacity) based on known coal parameters. The grinding zone of a vertical mill contains the grinding elements namely the table/ring/bowl (depending on mill design) and the roller/tire.
It is critical that the grinding elements maintain an efficient profile for as long as possible. As the grinding elements wear, the grinding efficiency of the mill declines. This is the reason why Magotteaux has developed increasingly resistant solutions (including Metal Matrix Composites where a high wear resistant alloy is reinforced with another material like ceramics) to increase the life and hence performance of coal pulverizing equipments.