CFD simulation of the steam gasification of millimeter-sized char particle using thermally thick treatment

Chen Tao; Kua Xiaoke; Lin Jianzhong

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CFD simulation of the steam gasification of millimeter-sized char particle using thermally thick treatment

机译：热厚处理毫米大小炭粒子蒸汽气化的CFD模拟

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A detailed char gasification model is developed using a multiphase Eulerian-Lagrangian algorithm and thermally thick treatment. The model is first validated by both gasification and combustion experiments of a millimeter-sized char particle. Temperature and mass loss histories as well as the particle morphology evolution correspond well with the existing results. Then the steam gasification of a 5 mm char particle is simulated and detailed physical and chemical conversion processes inside the particle are explored. During gasification, three distinct layers, i.e., the outer ash layer, the intermediate layer and the core layer, are identified based on the intraparticle porosity distribution. Simulation results show that the highest H2O and CO2 mass fractions locate in the ash layer, while the intermediate and core layers contain the highest H-2 and CO mass fractions, respectively. Moreover, effects of several parameters are also explored. It is found that the Stefan flow caused by the mass transfer plays a key role in determining the diffusion and convection behavior during gasification. The strength of the Stefan flow in the intermediate layer appears to be two orders of magnitude smaller than that of the inflow and has an influence on the shifting from a kinetically-controlled mode to a diffusion-controlled mode. In addition, the char consumption rate in the intermediate layer increases with an increase in steam mass fraction, gasification temperature and inflow velocity while it decreases with increasing particle diameter. Meanwhile, the char consumption rate caused by CO2 is much smaller than that due to steam. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

机译：使用多相欧拉维拉格算法和热厚处理开发了详细的Char气化模型。通过毫米大小的炭颗粒的气化和燃烧实验，首先验证该模型。温度和质量损失历史以及粒子形态的进化与现有结果很好。然后模拟5mm炭颗粒的蒸汽气化，并探讨了颗粒内的详细的物理和化学转化过程。在气化过程中，基于椎间内孔隙率分布鉴定三个不同的层，即外灰层，中间层和芯层。仿真结果表明，最高的H 2 O和CO 2质量级分位于灰分中，而中间体和芯层分别包含最高的H-2和CO质量分数。此外，还探讨了几个参数的效果。发现由传质引起的斯特凡流量在确定气化过程中的扩散和对流行为方面起着关键作用。中间层中斯特凡流的强度似乎是比流入的两个数量级，并且对从动力学上控制模式的影响到扩散控制模式。另外，中间层中的Char消耗率随蒸汽质量分数的增加而增加，气体质量和流入速度随着粒径的增加而降低。同时，由CO2引起的CHAR消耗率远小于由于蒸汽的小。（c）2019燃烧研究所。由elsevier Inc.出版的所有权利保留。

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来源
《Combustion and Flame》 |2020年第3期|63-86|共24页
作者
Chen Tao; Kua Xiaoke; Lin Jianzhong;
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作者单位

Zhejiang Univ Dept Engn Mech Hangzhou 310027 Peoples R China;

Zhejiang Univ Dept Engn Mech Hangzhou 310027 Peoples R China|Zhejiang Univ State Key Lab Clean Energy Utilizat Hangzhou 310027 Peoples R China;

Zhejiang Univ Dept Engn Mech Hangzhou 310027 Peoples R China;

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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
Char particle; Steam gasification; Porous media; Chemical reactions;

机译：炭颗粒;蒸汽气化;多孔介质;化学反应;

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CFD simulation of the steam gasification of millimeter-sized char particle using thermally thick treatment

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