Abstract: The effects of final temperature and heating rate on the pyrolysis characteristics of coking coal tailings were examined by fixed-bed reactor and TG analysis. The results show that the pyrolysis process of tailings can be divided into three stages: from ambient temperature to 400, 400~600 and 600~950℃. By comparing the TG-DTG curves of coking coal and tailings, their weight loss curves are basically similar and the DTG peak of tailings shifts toward higher temperature range. On this basis, the tailing pyrolysis kinetics model, using Coats-Redfern equation, shows that the activation energy of the pyrolysis of tailings is 22.6~66.2 kJ/mol and the pyrolysis process can be described as three second-order reactions. The experimental results in the fixed bed reactor with 30 g charge show that below 600℃ there is a little hydrogen formation and below 400℃ little hydrogen. The reaction remarkably occurs after 600℃, where the yield of hydrogen is increased simultaneously. The yields of gas and hydrogen are respectively 4300 and 1722 mL, at finial temperature 950℃ by 30 g tailings charge 7950 and 2716 mL by the same coking coal, and the yield of hydrogen-rich gas accounts for 54% of the total gas of coking coal, the tailings have a good yield and reuse value.

Key words: coking coal tailings, coking coal, yrolysis, kinetics, hydrogen evolution

摘要： 基于热重分析和固定床热解实验，研究了升温速率和温度对高矿物质含量的炼焦煤尾煤热解特性的影响. 尾煤热解过程可分为室温至400, 400~600及600~950℃三个阶段. 尾煤与焦煤热解曲线基本吻合，尾煤热解特征温度略向高温区推移. 采用Coats-Redfern积分法拟合计算了尾煤热解的动力学参数，得出反应活化能为22.6~66.2 kJ/mol，热解过程可用3个二级反应描述. 30 g尾煤固定床实验结果表明，氢气在低于400℃析出很少，400~600℃缓慢析出，之后随温度升高析出增加，600℃后大量析出，900℃左右达到最大析出量. 终温950℃时，30 g尾煤热解产气4300 mL，氢气产量1722 mL；焦煤产气7950 mL，氢气产量2716 mL. 尾煤热解富氢气体产量达焦煤热解气产量的54%，具有较高的再利用价值.

关键词: 炼焦煤尾煤, 焦煤, 热解, 动力学, 氢气析出