Effects of microwave/HAc-H2O2 desulfurization on properties of Gedui high-sulfur coal

A high-sulfur coking coal obtained from Shanxi province in northern China was desulfurized by microwave/HAc-H2O2 treatment. The main properties of coal samples before and after desulfurization treatment, including the elemental composition, caking index, organic constituents and sulfur content were analyzed. Experimental results showed that microwaving treatment at 500 W for 40 s combined with HAc-H2O2 (1:5 v/v) resulted in a yield of 99.27% clean coal and a desulfurization rate of 22.62%. Proximate and ultimate analyses showed that the ash content in coal was decreased from 9.09% to 7.90%, while the volatile matter significantly increased by 0.75%, and that the oxygen concentration in the coal increased from 4.15% to 7.08% following treatment. After desulfurization, the decreases in the caking index (from 72.4 to 45.42) and the impairment of calorific value was also observed. The negative impacts on the technological properties of coking coal may be attributed to oxidization caused by a HAc-H2O2 addition with the acceleration of microwaving. Results from FT-IR and XPS analyses depicted a considerable increase in oxygen-bearing functional groups, in accordance with results obtained by an ion-exchange titration method. These findings confirmed that the oxidization plays an important role in the present desulfurization process, and takes a dominant responsible for the changes of various properties of coal. (C) 2015 Published by Elsevier B.V.

采用微波/醋酸 - 过氧化氢处理对中国北方山西省的一种高硫炼焦煤进行了脱硫。分析了脱硫处理前后煤样的主要性质，包括元素组成、粘结指数、有机成分和硫含量。实验结果表明，在500瓦下微波处理40秒并结合醋酸 - 过氧化氢（体积比1:5），可得到产率为99.27%的精煤，脱硫率为22.62%。工业分析和元素分析表明，煤中的灰分含量从9.09%降至7.90%，而挥发分显著增加了0.75%，处理后煤中的氧含量从4.15%增加到7.08%。脱硫后，还观察到粘结指数下降（从72.4降至45.42）以及热值受损。对炼焦煤工艺性质的负面影响可能归因于添加醋酸 - 过氧化氢并在微波加速下所引起的氧化作用。傅里叶变换红外光谱（FT - IR）和X射线光电子能谱（XPS）分析结果表明，含氧官能团大幅增加，这与离子交换滴定法所得结果一致。这些发现证实，氧化在当前的脱硫过程中起着重要作用，并对煤的各种性质变化起主导作用。（C）2015年由爱思唯尔出版社出版。