鄂尔多斯褐煤超精煤的制备及其黏结性能

Caking property of hypercoal prepared from Ordos lignite

改变温度（300-400℃）和溶剂,高温萃取鄂尔多斯褐煤制备超精煤,通过红外、热重等手段分析不同工艺条件下超精煤结构的变化,考察超精煤黏结性的影响因素,并对超精煤进行常温分级萃取实验,进一步分离出超精煤的黏结组分,寻求超精煤黏结性的来源与性质。研究结果表明：通过高温萃取工艺,即使以不具有黏结能力的褐煤为原料,所得超精煤仍具有较高的黏结性。300℃下NMP萃取褐煤所得超精煤的黏结指数为89.6,而380℃下以洗油为溶剂所得超精煤的黏结指数则可达到98.2,这是由于以相对低温度和极性溶剂萃取,所得超精煤中含大量挥发性物质,易在煤热解之前分解挥发,阻碍了胶质体液相的形成,提高萃取温度和采用非极性溶剂则可以在有效减少含氧官能团等小分子组分的同时保证活性氢的含量,可以得到黏结性更高的超精煤。沥青质和前沥青质是超精煤的黏结组分,它们具有适中的分子量,含有大量脂肪和短环芳香结构,其含量决定了超精煤的黏结性。

The hypercoal was extracted from Ordos lignite by different solvents and high temperatures（ 300- 400 ℃）.The structural changes of hypercoal and the influence factors of its caking property was investigated by means of FT-IR,and TG analysis. The caking components were separated by classified extraction at room temperature from hypercoal to analyze the origin and property of caking components. The results show that： Hypercoal has high caking index by high temperature extraction despite its raw coal without caking ability. Hypercoal has high volatiles by relatively low temperature and polar solvent,these compounds are not conducive to the formation of plastic mass because of its intense volatilization before coal pyrolysis,in contrast,high extraction temperature and nonpolar solvent are beneficial for reducing oxygen containing functional groups and maintaining the active hydrogen content,so the caking indexes of hypercoal are 89. 6 and 98. 2 when using NMP and washing oil as solutions at 300 ℃ and 380 ℃,respectively. Asphaltene and preasphaltene are caking components in hypercoal with moderate molecular weight,they have many aliphatic hydrocarbons and polycyclic aromatic hydrocarbons,which determine the caking property of hypercoal.