褐煤低温干燥特性的实验研究

中国褐煤储量丰富，但较高水分极大地限制了其开采和利用，对其进行脱水提质是解决褐煤高效利用的关键。通过热重分析仪（TGA）对HL和YN的不同粒径褐煤，分别在50，80和110℃等温干燥2h。结果表明：在每个干燥温度下煤样都能达到恒重，随着温度的升高煤样总失重增加，说明煤中水分与煤表面之间具有不同的结合强度；随着水分的降低，水分蒸发所需能量增加，煤水之间的相互作用加强，其中包括氢键和微孔对水的束缚力。粒径0．250～0．150mm、水分26．61％的HL褐煤在50c（二干燥后，水分降至6．96％，此时水分以分子层水的形式存在；干燥温度升至110℃时，煤中水分并未明显降低，说明煤中官能团与水分子间形成的氢键对水分有强烈的吸附作用。HL褐煤50℃干燥后，0．150～0．074mm和0．074～0．038mm煤样残留水分分别为6．52％和3．93％，均低于0．250～0．150mm煤样的6．96％，说明0．250～0．150mm煤样中不能脱除的残留水是孔隙水，被禁锢在狭小空间内。

Low-temperature drying characteristics of lignite

Lignite reserves are abundant in China, but the high water content greatly limits its exploitation and utilization. The key to solve the efficient use of lignite is dehydration upgrading. The weight loss of HL and YN lignite with different particle size are determined at 50,80 and 110 ~C for 2 hours by thermal gravimetric analysis （TGA）. The results show that the weight loss of coal samples ahnost doesn＇t further increase after a period of dehydrate at each drying temperature, and the total weight loss increase with the drying temperature increase, indicating that the bonding strength between the coal surface and the water is different. The energy consumption for evaporation of water and the interaction including the hydrogen bonds and the binding force of microspores with water in coal increase with the water content decrease. The HL lignite,whose particle size ranging from 0. 250 mm to 0. 150 ram, moisture 26.61 percent,is dried at 50 ~C and the moisture decrease to 6.96 percent in the form of the molecular layer water. When the drying temperature further increase to 110 ~C , the moisture doesn＇t significantly decrease, which indicate that the hydrogen bond between functional groups and water molecule has strong adsorption for water. After dried at 50 ℃ ,the residual moisture of O. 150 mm to 0. 074 ram,0. 074 mm to 0. 038 mm and 0. 250 mm to 0. 150 mm HL lignite is 6.52 percent, 3.93 percent and 6.96 percent respectively. The results show that, the residual water in 0. 250 mm tO O. 150 mm lignite is pore water,which is trapped in a small space.