Abstract: The iron-based oxygen carriers with Al₂O₃ as an inert prepared by mechanical mixing were studied on thermal gravimetric analyzer(TGA).Through the thermograms reduced by CH₄,it was found that there was severe carbon deposition which even caused the mass curve to increase during reduction process. The concentration of reducing gas had a strong effect on the reaction rate as well as the degree of carbon deposition. At the same mass loss, higher concentration of the gas fuel tends to lead higher reaction rate while less carbon deposition. In addition, as the newly-generated carbon can be oxidized when introduced O₂, the amount of CO₂ during oxidation process can be applied to compare the level of carbon formation. With the redox cycles increased, the reaction was almost stable while the formation of carbon had a slightly downward tendency. Through analysis of the products with carbon deposition by X-ray diffraction and scanning electron microscope, there was Fe₃C generated and the other part of C existed on the carrier in the form of carbon filaments.

Key words: chemical-looping combustion, mechanical mixing, Fe-based carrier, carbon deposition

摘要： 利用热重分析仪对采用机械混合法自行制备的铁基载体还原过程中的积炭现象进行了实验研究。根据实验获得的热重曲线对铁基载氧体的CH₄还原特性进行了分析，实验结果表明，CH₄与铁基载氧体的还原反应过程中存在较为严重的积炭影响，且气体的浓度对反应有较大的影响。通过检测载氧体氧化过程中生成的CO₂量对这种影响进行了定量分析，结果表明积炭随着循环次数的增多而略有下降。XRD和SEM分析结果显示还原反应生成的C部分与载体反应生成Fe₃C，另一部分以碳丝的形式存在于载体表面以及颗粒之间。

关键词: 化学链燃烧, 机械混合法, 铁基载氧体, 积炭