【摘要】 采用酸洗脱灰、酸洗和Na/Co离子交换对两种低阶煤(MM和LY)进行预处理,然后以1-甲基萘为溶剂对预处理煤进行热溶剂提质萃取,把煤分成提质煤(UC)、高分子量萃取物(deposit)和低分子量萃取物(soluble)3种主要固体组分,以及少量水和气体产物。结果表明,通过脱灰和离子交换均提高了两种萃取物的收率及碳含量,并明显促进了煤中含氧官能团的脱除。脱灰后MM煤的高分子量萃取物收率从3.5%增加到9.5%,Na离子交换LY的低分子量萃取物的碳含量高达85.3%、氧含量低于6.4%。离子交换对两种萃取物的物理化学性质有明显的影响,Na+的影响尤为显著。酸洗脱灰和离子交换对低阶煤热溶剂提质萃取有明显促进作用。更多还原

【Abstract】 Dehydration and upgrading are essential pretreatment methods for efficient utilization of low-rank coal. In previous works the authors employed degradative solvent extraction method to dehydrate and upgrade low-rank coals and fractionate them into several fractions. For further study of this method,two low-rank coals( MM and LY) were pretreated by acid washing for demineralization or acid washing and Na/Co ion-exchange.The pretreated and raw coals were then extracted by 1-methylnaphthalene( 1-MN) at 350 ℃ and fractionated into upgraded coal( UC),high molecular weight extract( Deposit),low molecular weight extract( soluble),as well as a little H2 O and gas products. The results show that both acid washing and ion-exchange enhance the yields and carbon contents of the two extracts. Ion-exchange obviously promotes the removal of oxygen-containing functional group during extraction. The yield of high molecular weight extract of demineralized MM increases from 3. 5% to 9. 5%,and the carbon content and oxygen content of low molecular weight extract of Na ionexchanged LY are as high as 85. 3% and less than 6. 4%,respectively. Ion-exchange has a distinct influence on physical and chemical properties of the extracts. The influence of Na ion-exchange is especially remarkable.Thus,demineralization and ion-exchange have evident promotion for the degradative solvent extraction of low-rank coal.更多还原