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首页> 外文期刊>Combustion and Flame >Analysis of the errors associated with typical pulverized coal char combustion modeling assumptions for oxy-fuel combustion
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Analysis of the errors associated with typical pulverized coal char combustion modeling assumptions for oxy-fuel combustion

机译：与典型的粉煤焦燃烧模型假设相关的误差分析

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摘要

In CFD models of pulverized coal combustion, which often have complex, turbulent flows with millions of coal particles reacting, the char combustion sub-model needs to be computationally efficient. There are several common assumptions that are made in char combustion models that allow for a compact, computationally efficient model. In this work, oft used single- and double-film simplified models are described, and the temperature and carbon combustion rates predicted from these models are compared against a more accurate continuous-film model. Both the single- and double-film models include a description of the heterogeneous reactions of carbon with O_2, CO_2, and H_2O, along with a Thiele based description of reactant penetration. As compared to the continuous-film model, the double-film model predicts higher temperatures and carbon consumption rates, while the single-film model gives more accurate results. A single-film model is therefore preferred to a double-film model for a simplified, yet fairly accurate description of char combustion. For particles from 65 to 135 μm, in O_2 concentrations ranging from 12 to 60 vol.%, with either CO_2 or N_2 as a diluent, particle temperatures from the single-film model are expected to be accurate within 270 K, and carbon consumption rate predictions should be within 16%, with greater accuracies for a CO_2 diluent and at lower bulk oxygen concentrations. A single-film model that accounts for reactant penetration and both oxidation and gasification reactions is suggested as a computationally efficient sub-model for coal char combustion that is reasonably accurate over a wide range of gas environments.
机译：在煤粉燃烧的CFD模型中，煤粉燃烧通常具有复杂的湍流，有数百万个煤颗粒发生反应，因此焦炭燃烧子模型需要高效计算。焦炭燃烧模型中有几种常见的假设，它们允许使用紧凑的，计算效率高的模型。在这项工作中，描述了常用的单膜和双膜简化模型，并将这些模型预测的温度和碳燃烧速率与更准确的连续膜模型进行了比较。单膜和双膜模型都包括碳与O_2，CO_2和H_2O的异相反应的描述，以及基于Thiele的反应物渗透的描述。与连续膜模型相比，双膜模型预测更高的温度和碳消耗率，而单膜模型则给出更准确的结果。因此，对于焦炭燃烧的简化但相当准确的描述，单膜模型优于双膜模型。对于65至135μm的颗粒，O_2浓度范围为12至60体积％，使用CO_2或N_2作为稀释剂，单膜模型的颗粒温度预计在270 K以内是准确的，并且碳消耗率预测值应在16％以内，对于CO_2稀释剂的准确度较高，而总氧气浓度较低。建议将考虑反应物渗透以及氧化反应和气化反应的单膜模型作为煤焦燃烧的计算有效子模型，该模型在各种气体环境中都相当准确。

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  • 来源
    《Combustion and Flame》 |2013年第8期|1499-1509|共11页
  • 作者

    Ethan S. Hecht; Christopher R. Shaddix; JoAnn S. Lighty;

  • 作者单位

    Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112, USA,Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA;

    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA;

    Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Coal combustion; Gasification; Oxy-fuel;

    机译：燃煤;气化;含氧燃料;

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