Development of semi-parallel reaction model of devolatilization and heterogeneous reaction for pulverized coal particles
Development of semi-parallel reaction model of devolatilization and heterogeneous reaction for pulverized coal particles
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DOI：
10.1016/j.fuproc.2016.12.011
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发表时间：
2017-04
影响因子：
7.5
通讯作者：
Shota Akaotsu;J. Tanimoto;Tatsuya Soma;Y. Saito;Y. Matsushita;H. Aoki;Akinori Murao
中科院分区：
文献类型：
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作者：
Shota Akaotsu;J. Tanimoto;Tatsuya Soma;Y. Saito;Y. Matsushita;H. Aoki;Akinori Murao
建立了煤粉燃烧过程中煤颗粒脱挥与非均相反应的半平行反应模型。在不同反应温度和不同粒径条件下，分析了煤粒脱挥和焦炭氧化的准稳态传质过程，考察了脱挥产生的对流对流对氧化剂向颗粒表面传质的影响。焦炭脱挥后的氧化速率低于未脱挥发的焦炭。随着反应温度和颗粒直径的增加，这一趋势变得更加明显。这表明，脱挥产生的对流抑制了氧化剂向颗粒表面的传质，脱挥的影响取决于反应温度和颗粒直径。并将半平行反应模型计算的氧化速率与传统的序贯反应模型和平行反应模型的结果进行了比较。与其他模型相比，半平行反应模型更准确地反映了焦炭氧化速率随脱挥发分速率的增加而降低的规律。
A semi-parallel reaction model for the devolatilization and heterogeneous reaction of coal particles during pulverized coal combustion was developed. The quasi-steady mass transfer around a single coal particle with devolatilization and the oxidation of char were analyzed to investigate the effect of the convective flow generated by devolatilization on the mass transfer of the oxidant to the particle surface at various reaction temperatures and particle diameters. The oxidation rates of char with devolatilization were lower than those without devolatilization. This tendency became pronounced with increasing reaction temperature and particle diameter. This indicated that the convective flow generated by devolatilization inhibits the mass transfer of the oxidant to the particle surface and that the influence of the devolatilization depends on the reaction temperature and particle diameter. In addition, the oxidation rates estimated by the semi-parallel reaction model were compared with those obtained from the conventional sequential reaction model and parallel reaction model. In contrast to the other models, the semi-parallel reaction model more accurately represented the decrease in char oxidation rates with increasing devolatilization rate.