College of Energy Science and Engineering, Xi’an University of Science and Technology
College of Civil and Architectural Engineering, Xi’an University of Science and Technology
College of Chemistry and Chemical Engineering, Xi’an University of Science and Technology
Huaihe Energy (Group) Company Limited

褐煤干燥脱水是实现其高效利用、节能减排的重要技术措施。基于不同热风温度(60℃,80℃,100℃)和煤样粒度(小于2mm,2mm~5mm,5mm~7mm,7mm~10mm,10mm~13mm)对高西沟低阶褐煤单一热风干燥特性进行探讨,依次采用单一热风干燥、热风-红外串联和热风-红外并联联合干燥方式,通过实验分析了干燥过程褐煤水分比和干燥速率的变化特征,应用比能耗(QSEC)和能效(ηe)对比了三种干燥方式的能耗,采用SEM和FTIR分别分析了煤样表观形貌和官能团。结果表明:单一热风干燥温度越高,煤样与空气温差越大,煤样获得的热量越高,干燥速率越快;煤样粒度越小,煤样水分比下降越快,结束时的水分比越低;热风-红外串联联合干燥转换时间节点越早,所需干燥时间越短,在热风与红外干燥阶段干燥速率各出现一次最大值;并联干燥中褐煤水分比呈指数下降,并以降速期为主要阶段;三种干燥方式按比能耗由大到小依次为单一热风干燥(334.54MJ/kg)、热风-红外并联干燥(273.89MJ/kg)、热风-红外串联干燥(121.18MJ/kg),按能效(ηe)由大到小依次为热风-红外串联干燥(1.91%)、热风-红外并联干燥(0.83%)、单一热风干燥(0.69%),热风-红外串联干燥为较节能的干燥方式,此方式干燥后煤样相较原褐煤表面大面积坍塌,表面裂隙明显增多、增大,并且干燥煤样除水分外的其他官能团未发生变化。

Lignite drying and dehydration is an important technical measure to achieve its efficient utilization, energy saving, and emission reduction. The influences of different tempera-tures (60 ℃, 80 ℃, 100 ℃) and coal particle sizes (<2 mm, 2 mm-5 mm, 5 mm-7 mm, 7 mm-10 mm, 10 mm-13 mm) on drying characteristics of low-rank lignite from Gaoxigou using the hot-air drying method were investigated. Then the experiments were sequentially conducted under the same hot-air temperature and coal particle size using the hot-air in series with infrared drying method and the hot-air in parallel with the infrared drying method. The variation charac-teristics of lignite moisture ratio and drying rate during the drying process were analyzed by ex-periments. The specific energy consumption QSEC and energy efficiency ηe were used to compare the energy consumption of three drying methods. The apparent morphology and functional groups of coal samples were analyzed by SEM and FTIR, respectively. The results show that the higher the hot-air temperature, the higher the temperature difference between the coal sample and air, the higher the heat obtained by the coal sample, and the faster the drying rate. The smaller the coal particle size, the faster the moisture ratio dropped and the lower the moisture ra-tio at the end of the drying process. The earlier the time of the conversion between hot-air drying and infrared drying, the shorter the required drying time, and the drying rate appeares a maxi-mum once in each of the stages of the hot-air and the infrared drying. In parallel drying, the moisture ratio of lignite decreases exponentially, with the main stage being the decreasing rate period. The specific energy consumption QSEC value for the hot-air drying method is 334.54 MJ/kg, higher than 273.89 MJ/kg of the hot-air in parallel with the infrared drying method, and the 121.18 MJ/kg of the hot-air in series with infrared drying method is the smallest. The energy efficiency ηe value for the hot-air in series with infrared drying method is 1.91%, higher than 0.83% for the hot-air in parallel with the infrared drying method, and 0.69% for the hot-air dr-ying method is the smallest. Therefore, the hot-air series infrared drying method was the most energy-saving for the Gaoxigou lignite. Compared with the undried lignite, the dried coal sample by this method collapses on a large surface due to the removal of moisture from the particles, re-sulting in a significant increase in surface cracks and an increase in size. Additionally, the func-tional groups of the dry coal sample, except for water content, remained unchanged.

国家自然科学基金项目(41772166)和陕西省科技统筹重点产业创新链项目(2017ZDCXL-GY-10-1).

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NIU Tingting,XUE Hanling,LU Zehua,et al.Optimization and physical property analysis of hot air combined with infrared drying lignite[J].Coal Conversion,2024,47(2):1-11