加压水蒸气下年轻煤脱氧改质的研究

年轻煤是煤液化的良好原料 ,但它的氧含量高增加了煤液化过程中无用的氢耗 ,对这些煤进行脱氧改质有重要的意义 .选择了四种年轻煤——霍林河、小龙潭、义马和神华煤在高压釜内水蒸气气氛下进行了脱氧改质的研究 .结果表明 ,处理后煤样的氧含量和含氧官能团降低显著 ,氧的脱除率最高达到了 2 0 .7% .此外 ,煤质还有一些其他的变化 ,如热值和碳含量有所提高 ,最高内在水分和挥发分降低 ,表明煤阶有所提高 .对煤中的总酸性基、羧基和酚羟基的化学分析显示 ,脱氧改质后煤样的羧基、酚羟基等含氧官能团明显降低 ,羧基和酚羟基的最高脱除率分别达到了78.5 %和 31 .3% ,达到了脱氧改质的目的 .

STUDY ON THE DEOXY-MODIFICATION OF LOW RANK COALS UNDER PRESSURIZED VAPOUR CONDITIONS

Generally, low-rank coals are appropriate raw material of coal hydrolique-faction, but high oxygen content of lignites and a part of subbituminous coals results in a higher hydrogen consumption. For these coals the deoxy-modification is of significance. In this paper a series of deoxy-modification experiments for 4 selected coals-Huolinhe, Xiaolongtan, Yima and Shenhua were conducted under pressurized vapour condition in an autoclave. As a result, the oxygen content and oxygen containing functional group content of all treated coals obviously decreased, the highest removal rate of oxygen was reached 20.7%. The coal property experienced some changes-for example, the calorific value and carbon content increased, the moisture holding capacity and volatile matter decreased, showing that the coal rank somewhat raised. By chemical analysis, the acidic-carboxyl and phenolic groups were analyzed. The result indicated that after deoxy-modification treatments of low rank coals, their total acidic oxygen-containing functional groups including carboxyl and phenolic hydroxyl remarkably decreased. The highest removal rate of carboxyl and phenolic hydroxyl were respectively 78.5% and 31.3%. The goal of deoxy-modification of low-rank was achieved.