中文摘要：

针对燃用次烟煤等中高水分煤种机组运行过程中出现的效率偏低等问题，提出一种利用锅炉排烟直接预干燥原煤的发电系统，并以某典型600MW亚临界空冷机组为例，对干燥前后机组在设计工况下的热力学性能进行了对比分析；在此基础上，进一步探讨了原煤干燥程度对机组节能效果的影响规律，以及采用原煤预干燥机组获得的经济收益．结果表明：当该机组入炉煤脱水率为0．08kg（水分质量分数由22．6％降至15．9％）时，机组发电煤耗可降低4．0g／（kW·h），年均净收益可增加1000余万元，节能效果与经济效益显著．

英文摘要：

To solve the low efficiency problem existing in power plants burning medium- and high-moisture sub-bituminous coal, a raw coal pre-drying system was proposed by using boiler flue gas. Taking a typical 600 MW sub-critical air-cooling unit as an example, the thermodynamic performance was comparitively analyzed before and after coal pre-drying under design conditions, on which basis, the influence of coal predrying degree on the energy saving effect of unit was studied, while the economic benefit through coal predrying was further explored. Results show that when the dehydration rate is 0.08 kg, i.e. the moisture content is dried from 22.6% to 15.9% , the unit coal consumption rate can be reduced by 4.0 g/（kW ·h）, indicating an increase of annual net income by 10 million CNY, proving remarkable economic benefit of the coal pre drying system.