电站燃煤锅炉制粉系统石子煤量控制的影响因素及经济性分析

Analysis on Influence Factors and Economics of Quantity Control of Pulverizer Rejects in Milling System for Utility Boilers

依据石子煤的特性,分析了减少石子煤排量的利与弊,重点分析了制粉系统所减少的石子煤在进入炉内后的燃烧效率以及石子煤硫含量对高温腐蚀以及制粉系统和脱硫系统电耗的影响,并通过计算,分析了各个因素对减少石子煤排量的影响程度。分析结果表明石子煤是一种低热值、高硫分、难燃难磨的低品位燃料,其在炉内燃烧过程的热效率非常低。将石子煤送入炉膛燃烧,除了增加制粉系统电耗和脱硫系统电耗外,还将加重炉内的高温腐蚀或空气预热器的低温腐蚀,综合效益有可能是负值。因此,减少石子煤排量应慎重,应加强对此方面经济性的定量研究,指导电厂正确控制石子煤排量、挖掘节能减排潜力。

According to the characteristics of pulverizer rejects,the advantages and disadvantages of the reduction of pulverizer rejects are analyzed,particularly with the emphasis on the combustion efficiency of the pulverizer rejects returned to the furnace,the impact of the sulfur content of pulverizer rejects on high-temperature corrosion and the power consumption by the milling system and the desulfurization system.Through calculation,the impact of these factors on the reduction is studied,which concludes that pulverizer rejects are a kind of low quality fuel with low heat value,high sulfur content,poor grindability,bad inflammability and low combustion efficiency.When pulverizer rejects return to the furnace,not only the power consumption of the milling system and the desulfurization system will increase,but also the high-temperature corrosion in the furnace and the low-temperature corrosion in the air heater will deteriorate,which will result in negative comprehensive benefits.Therefore,reducing the quantity of pulverizer rejects needs more attention and carefulness.Quantitative studies on the economics of the utilization of pulverizer rejects should be enhanced to instruct power plants through the quantity control of pulverizer rejects in milling systems.