为提高褐煤干燥系统能源利用率及高效回收干燥尾气中的水分和热能,提出一种基于烟气再循环技术的褐煤干燥系统,利用Matlab对系统进行建模,并对系统的节能性、安全性及水回收效益进行了仿真计算和分析. 结果表明,该系统属于低温干燥,以循环烟气代替空气,干燥介质含氧量与含湿量均大幅下降,工艺更加安全可靠,有效提高了干燥过程的传热与传质强度,提高系统热效率. 与传统烟气-空气混合煤干燥系统相比,烟气混合干燥系统煤耗为39. 60 kg/t,降低7. 62%;热效率和火用效率分别提高4. 31%和3. 01%;回收水流量为1. 73 t/h,未产生新的污染物,更加节能环保;干燥介质含湿量降低37. 21 g/kg,干燥强度更加剧烈,有利于减少干燥耗时;氧气体积分数降低7. 84%,解决了褐煤干燥系统的安全问题.%To improve efficiency of lignite drying system and recovery of dry exhaust moisture and heat,a lignite drying system based on flue gas recirculation technology was proposed,and the mathematical model was established by MATLAB. The energy saving,security and water recovery efficiency of the system were simulated and analyzed. The results showed that the system was low temperature drying,which used flue gas as drying medium,the oxygen content and moisture of drying medium reduced significantly,the process was more reliable and effective. The heat transfer and mass transfer intensity and thermal efficiency of the system were improved. Compared to the traditional coal drying systems which used flue gas and air mixture as drying medium,the coal consumption of the system reduced to 39. 60 kg/t by 7. 62%,thermal efficiency and exergy efficiency was 4. 31% and 3. 01% respectively,recycling water flow was 1. 73 t/h and no new pol-lutants generated,the system was more environmentally friendly. The moisture content of the drying medium reduced by 37. 21 g/kg and the dry intense was enhanced,which shortened drying time. The oxygen concentration reduced by 7. 84%,which solved the security prob-lem of lignite drying system.
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