Thermal behavior and the evolution of char structure during co-pyrolysis of platanus wood blends with different rank coals from northern China
Thermal behavior and the evolution of char structure during co-pyrolysis of platanus wood blends with different rank coals from northern China
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DOI：
10.1016/j.fuel.2015.06.023
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发表时间：
2015-10
期刊：
影响因子：
7.4
通讯作者：
Meng Haiyu;Shuzhong Wang;Lin Chen;Zhiqiang Wu;Jun Zhao
中科院分区：
文献类型：
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作者：
Meng Haiyu;Shuzhong Wang;Lin Chen;Zhiqiang Wu;Jun Zhao
生物质与煤的共热化学转化作为减少温室气体排放的有效手段得到了广泛的研究。成功地评价共热解过程的热行为和产物特性对于预测共热解过程的性能和提高其效率具有重要意义。采用热重分析仪研究了悬铃木、两种不同煤阶煤（平庄褐煤和神木烟煤）及其混煤在热解过程中的热行为。利用拉曼光谱技术研究了煤焦结构的变化。热重实验表明，单组分和共混比不能准确预测共混物的热解特性。共混物热失重曲线的非加和行为表明存在协同效应，这可以促进共热解过程中的挥发分产率。当平庄褐煤和神木烟煤的配煤比例分别为30%和50%时，协同效应最明显。此外，还采用等转化率法求解活化能。观察到共混物的平均活化能值的非加和性性能。拉曼光谱结果表明，随着梧桐木配比的增加，共混物热解半焦的拉曼峰强度也随之增加，这可能是由于含氧基团的竞争增加以及碱金属和碱土金属物种的不成比例影响所致。几个主要的拉曼谱带的强度比可以提供有关煤焦结构演化的有用信息。梧桐木掺混比例越高，煤焦中芳香环结构越小（3-5个稠环）。
Co-thermochemical conversion of biomass and coal has been extensively investigated as an effective means to reduce the emission of greenhouse gas. Successful evaluation on the thermal behavior and product characteristics of the co-pyrolysis process is of crucial importance for predicting performance and improving efficiency of this technology. In this study, thermal behavior of platanus wood, two different rank coals (Pingzhuang lignite and Shenmu bituminous) and their blends during pyrolysis were studied via thermogravimetric analyzer. Raman spectroscopy technique was further employed to study the evolution of char structure. Thermogravimetric experiments indicated that the pyrolysis characteristics of their blends cannot be accurately forecasted based on individual component and blending ratio. The non-additive behavior of thermogravimetric curves of the blends suggested the existence of synergistic effects, which can promote the volatiles yields during the co-pyrolysis process. The most obvious synergistic effects were observed when the coal blending ratios were 30% for Pingzhuang lignite and 50% for Shenmu bituminous, respectively. In addition, iso-conversional method was used to solve activation energy. Non-additivity performance in the mean activation energy values of the blends was observed. The Raman results revealed that as the platanus wood blending ratio increased the Raman peak intensities of the char samples from pyrolysis of the blends also increased, which was probably attributed to the competition of oxygen-containing groups increment and disproportional impact of alkali and alkaline-earth metal species. The intensity ratios of some major Raman bands can provide useful information on char structure evolution. The generation of smaller aromatic rings structures (3–5 fused rings) was favored in these char samples with the higher platanus wood blending ratio.