Effect of mass transfer and bulk flow on the zinc oxide reduction by methane
Effect of mass transfer and bulk flow on the zinc oxide reduction by methane
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DOI：
10.1021/ie010604r
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发表时间：
2002-05-29
影响因子：
4.2
通讯作者：
Jamshidi, E
中科院分区：
文献类型：
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作者：
Ebrahim, HA;Jamshidi, E
甲烷还原氧化锌是一种新的锌生产工艺。与传统碳热还原炉相比，该方法的优点是操作温度较低，间接冷凝器简单，合成气的共制备。已经在热重（TG）标度上和在中等温度下广泛地研究了在化学控制方案下通过CH 4还原ZnO的动力学（Ale Ebrahim，H.; Jamshidi，E. 2001，79A，62-70）。在大ZnO颗粒的工业规模上，即使在中等温度下，传质和整体流动也是有效的。因此，需要一个成功的数学模型来设计这样的工业工厂。在这项工作中，ZnO + CH 4反应在高温（1000 degreesC）进行了研究，其中动力学阻力显着降低。因此，可以在TG标度上考虑传质和整体流动的影响。在此基础上，建立了一个包含外部传质、整体流动和颗粒表面化学反应的混合控制模型。在这项工作中，从热重法获得的实验数据与混合控制模型预测吻合得很好。
Zinc oxide reduction with methane can introduce a new zinc-producing technology. The advantages of this method with respect to conventional carbothermic furnaces are lower operating temperatures, a simple indirect condenser, and copreparation of synthesis gas. The kinetics of ZnO reduction by CH4 at the chemical control regime has been studied on the thermogravimetric (TG) scale and at moderate temperatures extensively (Ale Ebrahim, H.; Jamshidi, E. Trans. Inst. Chem. Eng. 2001, 79A, 62-70). On the industrial scale with large ZnO pellets, mass transfer and bulk flow will be effective even at moderate temperatures. Therefore, a successful mathematical model for the design of such industrial plants is needed. In this work the ZnO + CH4 reaction at high temperature (1000 degreesC) was studied, where the kinetic resistance decreased considerably. Thus, the effect of mass transfer and bulk flow can be considered in on the TG scale. Then a mixed control model was developed which contains the effects of external mass transfer, bulk flow, and chemical reaction at the pellet surface. The obtained experimental data from thermogravimetry in this work were in good agreement with the mixed control model predictions.