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Chemical and physical structural studies on two inertinite-rich lump coals.

机译：对两种富含惰质的块煤的化学和物理结构研究。

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摘要

Two Highveld inertinite-rich lump coals were utilized as feed coal samples in order to study their physical, chemical structural and petrographic variations during heat treatment in a packed-bed reactor unit combustor.udThe two feed lump coals were selected as it is claimed that Coal B converts at a slower rate in a commercial coal conversion process when compared to Coal A. The reason for this requires detailed investigation.udChemical structural variations were determined by proximate and coal char CO2 reactivity analysis. Physical structural variations were determined by FTIR, BET adsorption methods, XRD and 13C Solid state NMR analysis. Carbon particle type analysis was conducted to determine the petrographic constituents of the reactor generated samples, their maceral associations (microlithotype), and char morphology. This analysis was undertaken with the intention of tracking the carbon conversion and char formation and consumption behaviour of the two coal samples within the reactor.udProximate analysis revealed that Coal A released 10 % more of its volatile matter through the reactor compared to Coal B. Unburnt carbon in the ash bed zone was observed for both coal samples (Coal A and B), and it was attributed to incomplete carbon conversion. Coal char CO2 reactivity analysis showed that indeed Coal A is more reactive than Coal B. Qualitative FTIR analysis showed that both coals follow similar trends when exposed to high temperatures. Coal structural characterization revealed that Coal A has higher surface area when compared to Coal B. XRD analysis revealed that Coal A has less aromatic crystallites and lower Lc values compared to Coal B. It was observed that the coal structural properties of Coal A became more ordered and aligned at lower temperatures (289 0C), whereas Coal B starts at higher temperatures (693 0C). 13C Solid state NMR results showed that Coal B is more aromatic than Coal A implying that it is difficult to gasify/combust Coal B. Petrography analysis showed that Coal A has 34.6 vol % reactive macerals of which 78 % is from liptinite and vitrinite contents. Coal B has 53.6 vol % of reactive macerals of which 49 % was from liptinite and vitrinite, the other 51 % is from reactive semifusinite and inertodetrinite. The 49/51 split between reactive maceral value for Coal B may explain the lower reactivity compared to Coal A. Coal B appeared to produce more inert char particles, ran at higher temperatures in the ash bed because of its aromatic richness than Coal A. This was also attributed to the fact that Coal B has higher inertinite content than Coal A. The allocation of parent coal samples to “reactive” and “inert” macerals gave more in depth results that were able to show a possible reason behind reactivity difference occurring during the coal conversion process and support the structural analysis results obtained for these parent coal samples. The reactivity difference of these parent lump coal samples appears to be greatly influenced by the chemical reactions (structure) of these samples more than the kinetic reactions (pressure, temperature, reaction rates etc.) of these samples.
机译：为了研究填充床反应器单元燃烧器中热处理过程中的物理，化学结构和岩石学变化，使用了两种Highveld富含惰质石的块煤作为进料煤样品。 ud选择了两种进料块煤是因为与商品A相比，商品B在商业煤转化过程中的转化速度较慢。其原因需要详细研究。 ud化学结构的变化是通过近距离和煤焦CO2反应性分析确定的。物理结构变化是通过FTIR，BET吸附法，XRD和13C固态NMR分析确定的。进行了碳颗粒类型分析，以确定反应堆生成的样品的岩石学组成，其宏观缔合（微石版型）和炭的形态。进行此分析的目的是跟踪反应器内两个煤样品的碳转化率，焦炭形成和消耗行为。 ud接近的分析显示，与煤B相比，煤A通过反应器释放的挥发物多10％。在两个煤样品（煤A和煤B）中都观察到灰床区未燃烧的碳，这归因于碳转化不完全。煤焦的CO2反应性分析表明，煤A确实比煤B具有更高的反应性。定性FTIR分析表明，两种煤在高温下都遵循相似的趋势。煤的结构特征表明，与煤B相比，煤A的表面积更大。X射线衍射分析表明，与煤B相比，煤A的芳族微晶含量较低，Lc值较低。观察到，煤A的煤结构特性变得更有序并在较低的温度（289 0C）下对齐，而煤B在较高的温度（693 0C）下开始。 13 C固态NMR结果表明，煤B比煤A更芳香，这意味着难以将煤B气化/燃烧。岩相分析表明，煤A具有34.6体积％的反应性化学成分，其中78％来自脂铁矿和镜质石。煤B的反应性化学成分为53.6％（体积），其中49％来自锂皂石和镜质体，其他51％来自反应性半纤锌矿和惰性硅藻土。煤B的反应性一般值之间的49/51比值可能解释了与煤A相比较低的反应性。煤B似乎产生更多的惰性炭颗粒，由于其芳香性比煤A高，因此在灰分床中的运行温度更高。这也归因于煤B的惰质含量高于煤A。将母体煤样品分配给“活性”和“惰性”微晶的结果更深，能够显示出在反应过程中发生反应性差异的可能原因煤转化过程，并支持这些母煤样品获得的结构分析结果。这些母块煤样品的反应性差异似乎受这些样品的化学反应（结构）的影响大于这些样品的动力学反应（压力，温度，反应速率等）。

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    Malumbazo Nandi;

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  • 年度 2011
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