锅炉烟气预干燥褐煤发电系统热经济性计算分析

对褐煤进行预干燥可以明显地提高直接燃褐煤电站发电效率,滚筒烟气干燥是应用最早的干燥方法。为此,文中建立了锅炉烟气预干燥燃褐煤发电系统的热经济性分析模型,并且利用该模型对某600 MW机组采用锅炉烟气干燥对发电系统热效率的影响因素进行了计算分析。计算结果表明采用锅炉烟气预干燥,在文中所述的基准工况下可以降低发电煤耗3.18 g(kW·h)1;烟气温度每变化10℃,节煤量变化1.1 g(kW·h)1;从1 kg褐煤中每多干燥出0.1 kg的水分,节煤量增加0.6g(kW·h)1左右;只有在烟气干燥机具备较高的热效率时,发电系统增加烟气干燥机后才能起到节能效果,烟气干燥机热效率每提高1%,在干燥程度分别为0.1、0.2、0.3 kg·kg1时,可分别增加节煤量0.1、0.16、0.23g(kW·h)1。

Thermal Economic Calculation and Analysis for Boiler Flue Gas Pre-dried Lignite-fired Power Generation System

Lignite Pre-drying can obviously improve the power generation efficiency of directly lignite-fired power plant,and rotary drying is the earliest application lignite pre-drying method.Therefore,a theoretical economic analysis model for boiler flue gas pre-dried lignite-fired power generation system was established,with which a case study on a 600 MW power generation system was conducted to analyze the factors influencing thermal efficiency.The results show that: lignite pre-drying with boiler flue gas dryer can reduce the coal consumption rate by 3.18 g(kW·h) 1 at bench mark condition listed;when the boiler temperature changes by every 10 ℃,the coal consumption rate will change 1.1 g(kW·h) 1;the coal consumption rate will increase 0.6 g(kW·h) 1 when 0.1 kg more water is dried out of lignite;The boiler flue gas dryer can increase thermal efficiency only when the dryer has enough thermal efficiency,and the coal consumption rate will increase by 0.1,0.16,0.23 g(kW·h) 1 when the dryer has 1% higher thermal efficiency at the degree of drying at 0.1,0.2,0.3 kg·kg 1.