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首页> 外文学位 >A STUDY OF CHAR GASIFICATION REACTIONS (COAL CONVERSION, COMBUSTION, CATALYTIC, MODELING, PORE STRUCTURE).
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A STUDY OF CHAR GASIFICATION REACTIONS (COAL CONVERSION, COMBUSTION, CATALYTIC, MODELING, PORE STRUCTURE).

机译：焦炭气化反应（煤转化，燃烧，催化，模型化，孔结构）的研究。

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Structural, kinetic and catalytic effects relevant to the combustion and gasification of coal-derived chars were investigated. A Texas lignite, an anthracite and two bituminous coals, Pittsburgh #8 and Illinois #6, were pyrolyzed in a nitrogen atmosphere to prepare chars. Optical microscopy, mercury porosimetry and gas adsorption techniques using nitrogen, CO(,2) and CO, were employed for pore structure characterization. The micropores present in the lignite char were accessible to all adsorbents. However, a substantial fraction of the pore space in other chars was inaccessible to nitrogen at 77(DEGREES)K. The lignite char also exhibited the fastest rates of gaseous diffusion, followed in order of decreasing diffusivities by the Illinois #6, Pittsburgh #8 and anthracite chars.; The changes in reactivities and pore structures of chars were measured experimentally during their reaction with oxygen (400-550(DEGREES)C) and CO(,2) (800-1000(DEGREES)C). For a particular char-gas system, the normalized rate-conversion pattern was invariant with respect to temperature and gaseous concentration. In the case of lignite and Pittsburgh #8 chars, the rate-conversion pattern was similar during reaction with oxygen and CO(,2). Adsorption experiments on partially reacted chars indicated that the micropores in the lignite char were accessible to both reactants. The micropores in the Illinois #6 char were, however, not accessible during its reaction with oxygen.; The evolution of pore structure during reaction was modeled by using a probabilistic approach which accounts for overlapping pores with different shapes and sizes. A priori predictions of pore structure evolution are obtainable from the structural measurements on unreacted char. The model predictions were validated using the experimental data reported in literature and the data obtained in this work.; The kinetics of gasification of the lignite and the Pittsburgh #8 chars was studied using a Langmuir-Hinshelwood type kinetic expression to correlate the experimental data. CO was found to inhibit the reaction substantially.; The effect of a potassium carbonate catalyst on the reaction of these two chars was also investigated. A marked change in the reactivity-conversion pattern was observed when the catalyst impregnated char samples were reacted with oxygen and CO(,2). Substantial increases in reaction rates were observed, and the enhancement was approximately proportional to the catalyst loading.
机译：研究了与煤焦炭燃烧和气化有关的结构，动力学和催化作用。将德克萨斯州褐煤，无烟煤和两种烟煤（匹兹堡8号和伊利诺伊州6号）在氮气氛下热解以制备炭。使用光学显微镜，汞孔隙率法和使用氮气，CO（，2）和CO的气体吸附技术进行孔结构表征。褐煤焦炭中存在的微孔可被所有吸附剂利用。然而，氮在77（DEGREES）K下几乎无法进入其他碳中的大部分孔隙。褐煤炭还表现出最快的气体扩散速率，其次是伊利诺伊州6号，匹兹堡8号和无烟煤炭，其扩散率递减。在与氧气（400-550（DEGREES）C）和CO（，2）（800-1000（DEGREES）C）反应期间，通过实验测量了焦炭的反应性和孔结构的变化。对于特定的焦气系统，归一化的速率转换模式相对于温度和气体浓度是不变的。在褐煤和匹兹堡8号煤的情况下，在与氧气和CO（，2）反应期间速率转换模式相似。在部分反应的焦炭上的吸附实验表明，褐煤焦炭中的微孔对两种反应物都是可及的。但是，伊利诺伊州＃6煤焦中的微孔在与氧气反应时无法进入。通过使用概率方法来模拟反应过程中孔结构的演变，该方法考虑了具有不同形状和大小的重叠孔。孔隙结构演变的先验预测可从对未反应焦炭的结构测量中获得。使用文献中报道的实验数据和在这项工作中获得的数据验证了模型的预测。使用Langmuir-Hinshelwood型动力学表达式研究了相关数据，研究了褐煤和匹兹堡8号煤焦的气化动力学。发现CO基本上抑制了反应。还研究了碳酸钾催化剂对这两种炭的反应的影响。当催化剂浸渍的炭样品与氧气和CO（，2）反应时，观察到反应活性转化模式的显着变化。观察到反应速率显着增加，并且该增加与催化剂负载量大致成比例。

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