针对燃煤电厂提出一种原煤低温预干燥技术,并讨论了采用该干燥技术后燃煤电厂在设备和辅机电耗方面的变化.通过理论推导得出原煤中水分对原煤低位发热量及机组热力学性能的影响.以典型的原煤低位发热量和供电效率为例,计算分析了不同低位发热量的原煤采用不用程度的低温预干燥后自身低位发热量的变化,以及对不同机组供电煤耗率的影响.结果表明:如采用电厂废热干燥原煤且不考虑辅机电耗,煤中水分相对于干燥前每降低1%,可使低位发热量上升1.2%~1.5%,供电煤耗率下降0.3~0.6g/(kW·h),节能效果显著;原煤低温预干燥系统简单、投资可控,是一种极具潜力的普适性电厂节能技术.
A concept of low-temperature coal pre-drying was proposed for coal-fired power plants, while the changes in equipment configuration and auxiliary power consumption were discussed after application of the pre-drying technology. The effects of moisture content in coal on its low heating value (LHV) and on thermodynamic performance of the unit were comprehensively analyzed. Taking the low heating value of typical raw coal and the coal consumption rate of power supply as an example, their changes after application of low-temperature coal pre-drying were calculated. Results show that the LHV of coal would be increased by 1.2%-1.5% and the coal consumption rate would be reduced by 0.3-0.6 g/(kW · h), for every 1% drop of moisture content in coal, using waste heat as the drying source, without considering the energy consumption of auxiliaries, indicating remarkable energy-saving effects. Featured by simple structure and controllable investment, the low-temperature coal pre-drying technology is a very promising and effective energy-saving method, which is universally applicable to coal-fired power plants.