Qiu Shuxing, Zhang Shengfu, Fang Yunpeng, Qiu Guibao, Yin Cheng, Reddy Ramana G, Zhang Qingyun, Wen Liangying
College of Materials Science and Engineering, Chongqing University Chongqing 400044 China
Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials, Chongqing University Chongqing 400044 China.
RSC Adv. 2019 Sep 9;9(48):28053-28060. doi: 10.1039/c9ra03938d. eCollection 2019 Sep 3.
Three-stage absorption by butyl acetate was used to obtain tar components during the co-pyrolysis of fat coal and poplar at high temperature. The resulting tar yields were calculated relative to the fat coal and poplar blends. The tar components were characterized by gas chromatography-mass spectrometry, Fourier transform-infrared spectroscopy and H nuclear magnetic resonance spectroscopy. The effects of the added poplar on tar formation were then considered. The results show that the poplar-fat coal tar yield rose slightly when the poplar addition levels ranged from 4% to 12% and then increased much more at higher poplar addition levels. Oxygenated and aromatic compounds contributed greatly to the poplar-fat coal tar yield. The quantity of oxygenated components increased in the poplar blending ratio range from 4% to 12% and decreased as the ratio increased further, while the quantity of aromatic components showed the opposite trend. The influences of poplar addition levels on tar formation could be divided into two stages: (a) lighten the tar by stabilizing radicals at low poplar addition levels; (b) form heavier tar due to cross-linking reactions of the remaining radicals at high poplar addition levels. When the poplar addition levels ranged from 4% to 12%, due to synergistic effects, large amounts of free radicals and hydrogen from the co-pyrolysis of coal and poplar formed lighter stable compounds, which were then transported into the tar. Further, cross-linking reactions could be decreased because fewer free radicals and less hydrogen remained. As a result, the amount of PAHs declined, the tar yield rose slightly, the hydrocarbon-generating potential improved, the aliphatic chain length shortened, and the aromatic protons decreased. At higher blending ratios, excess radicals existed after stabilization due to the increasing poplar addition levels. These radicals underwent cross-linking reactions and produced PAHs, resulting in heavily increased tar yields, weakened hydrocarbon-generating potential, extended aliphatic chain lengths and increased aromatic protons.
采用乙酸丁酯三级吸收法在高温下对肥煤和杨树进行共热解以获取焦油成分。所得焦油产率相对于肥煤和杨树混合物进行计算。通过气相色谱 - 质谱联用、傅里叶变换红外光谱和氢核磁共振光谱对焦油成分进行表征。然后考虑添加杨树对焦油形成的影响。结果表明，当杨树添加量在4%至12%范围内时，杨树 - 肥煤焦油产率略有上升，而在更高的杨树添加量时上升幅度更大。含氧化合物和芳香族化合物对杨树 - 肥煤焦油产率贡献很大。在杨树掺混比例为4%至12%范围内，含氧化合物数量增加，随着比例进一步增加而减少，而芳香族成分数量则呈现相反趋势。杨树添加量对焦油形成的影响可分为两个阶段：(a) 在低杨树添加量时通过稳定自由基来减轻焦油；(b) 在高杨树添加量时由于剩余自由基的交联反应形成更重的焦油。当杨树添加量在4%至12%范围内时，由于协同效应，煤和杨树共热解产生的大量自由基和氢形成了更轻的稳定化合物，然后进入焦油中。此外，由于剩余的自由基和氢减少，交联反应可以减少。结果，多环芳烃的量下降，焦油产率略有上升，生烃潜力提高，脂肪链长度缩短，芳香质子减少。在更高的掺混比例下，由于杨树添加量增加，稳定后存在过量自由基。这些自由基发生交联反应并产生多环芳烃，导致焦油产率大幅增加，生烃潜力减弱，脂肪链长度延长，芳香质子增加。
