褐煤干燥特性及产品特性研究

Lignite drying and properties of upgrading lignite

通过对内蒙古锡林浩特褐煤的热重分析可知,褐煤干燥过程约30 min,干馏过程约1.5 h。对不同粒径褐煤进行了干燥特性研究,说明+100,100～50,-50 mm原煤完全干燥分别需要4.0,1.0,0.5 h,粒径越小,煤样失重率越大,干燥速度越大,达到相同干燥效果所需的干燥时间也越短。最后分析了干燥温度对产品特性的影响,同时测试了干燥、干馏提质产品的自燃特性和复吸水特性,结果表明:与原煤相比,150,200℃产品挥发分分别提高了33.72%和31.13%,更易发生自燃,而550℃干馏过程中挥发分降低了30.89%,热稳定性大幅增加;150,200,550℃产品吸氧量分别提高了0.43,0.65,0.72 cm3/g;干燥产品燃点要低于原煤,而干馏产品燃点则高于原煤;干馏煤因改变了孔隙结构,最高内在水分降低,即复吸水的能力降低。因此,干燥提质产品与褐煤性质基本一致,而干馏提质产品性能则获得较大改善。

Thermal gravimetic analysis of Inner Mongolia Xilinhot lignite shows that the drying and pyrolysis process is about 30 minutes,1.5 h.To thoroughly dry ＋100,100 to 50,-50 mm coal samples need 4.0,1.0,0.5 h respectively.The smaller the particle size of coal samples,the greater the weight loss rate and drying rate,the shorter the drying time required to achieve the same drying effect.The influence of drying temperature on the characteristics of the product,the spontaneous combuston characteristics and water re-absorption characteristics of drying and pyrolysis products show that,compared with lignite,the volatile content of products gotten at 150 ℃ and 200 ℃,increases by 33.72 percent and 31.13 percent and they are easier self-fire.The volatile matter of 550 ℃ pyrolysis products decrease by 30.89 percent while thermal stability is dramatically increase.Oxygen absorption quality of 150,200,500 ℃ products are enhanced by 0.43,0.65,0.72 cm3/g respectively.Drying coal ignition temperature is lower than lignite while the ignition temperature of the pyrolysis products is higher than the lignite.The maximum inherent moisture of pyrolysis lignite is decreased due to its changed pore structure.Therefore,the quality of drying lignite is basically the same as the lignite,while the quality performance of pyrolysis product is greatly improved.