集成煤泥干燥的掺烧发电系统热力学-技术经济性分析

Thermodynamic and Economic Analyses on Mixed Combustion Power System Integrating with Coal Slime Drying

为了提高煤泥的综合利用效率,在煤泥掺烧发电系统的基础上耦合煤泥干燥技术,分别构建了集成煤泥蒸汽/空气干燥的掺烧发电系统,基于热力学基本定律和技术经济基本理论,建立了系统热经济性和技术经济性分析模型,以某660 MW燃煤机组为例开展了系统能量分析、㶲分析及技术经济性分析。结果表明:集成煤泥蒸汽/空气干燥的掺烧发电系统在煤泥掺混比为25%~90%时的节煤量分别为2.07~9.44 g/(kW·h)和1.19~5.43 g/(kW·h),其节能本质为煤泥炉前脱水过程中低品位能量代替高品位能量作为热源,降低了燃烧过程㶲耗散和排烟㶲损失;系统投资回收期分别为5.0 a和3.1 a, 20 a内净现值最大分别为694.1万元和540.5万元;从热力学/技术经济性角度(电站剩余寿命小于8.9 a)来看,集成煤泥蒸汽/空气干燥的掺烧发电系统性能更优。

In order to improve the comprehensive utilization efficiency of coal slime,the coal slime drying technology was coupled with the coal slime mixed combustion power system.Coal slime mixed combustion power systems integrating with steam/air drying were constructed.Based on the basic law of thermodynamics and the theory of technical economy,analysis models of thermo-economic and techno-economic for the system were established,respectively.Energy,exergy and economic analyses on the system of a 660 MW coal-fired unit were carried out.Results show that the coal saving capacity of the coal slime mixed combustion power systems integrating with steam/air drying is 2.07-9.44g/(kW·h)and 1.19-5.43g/(kW·h),respectively,when the coal slime ratio is 25%-90%.The energy saving essence of the system is that heat source in the drying process before coal slime furnace is low-grade energy rather than the highgrade energy,which reduces irreversible loss in combustion process and exergy loss in flue gas emissions.Payback periods of the coal slime mixed combustion power systems integrating with steam/air drying are 5.0years and 3.1years,and the maximum net present values in 20years are 6.941million yuan and 5.405 million yuan,respectively.From the perspective of thermodynamics/technology and economy,the performance of the coal slime mixed combustion power systems integrating with steam/air drying is better when the power plant remaining life is less than 8.9years.