汽轮机抽汽干燥褐煤对电厂经济性影响的计算分析

Study on the Economy Influence of Drying Lignite with Steam in the Power Plant

褐煤是一种高水分低热值的劣质煤炭,电厂直接掺烧褐煤会导致制粉系统干燥出力不足、锅炉热效率低、一次风率高等问题。利用蒸汽管回转式干燥机对褐煤进行预干燥,电厂可以实现完全燃用褐煤,改善锅炉制粉系统出力,提高锅炉热效率。以某300 MW燃煤机组为研究对象,研究在电厂中用汽轮机抽汽干燥褐煤对电厂热经济性的影响,并结合燃料成本比较电厂经济效益的变化。计算发现,增加干燥系统后,电厂供电标准煤耗率增加了18.12 g/kW.h,每小时多耗标煤4.67 t/h,电厂热经济性下降;但是由于褐煤的价格便宜,电厂全部燃用褐煤可以节省燃料成本,经济效益是增加的。

Lignite is a kind of high moisture low heat value coal. Power plant burning lignite directly will lead to coal pulverizing system output insufficient and low boiler thermal efficiency. Use the steam pipe rotary dryer to dry lignite, the power plant can realize burning lignite only, and the pulverizing system output will be improved. By taking a 300MW coalfired unit as the research object, the paper studied the influence of the steam pipe rotary dry er for the thermal efficiency of power plants, and compared the economic benefit with fuel cost. Through theoretical calculation, it make power generation consume 4. 07t/h more standard coal, the thermal efficiency of power plant declined ; Burning lignite can also save great fuel cost for power plant because of its low price.