Production of syngas from pyrolysis of biomass using Fe/CaO catalysts: Effect of operating conditions on the process
Production of syngas from pyrolysis of biomass using Fe/CaO catalysts: Effect of operating conditions on the process
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DOI：
10.1016/j.jaap.2017.05.007
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发表时间：
2017-05-01
影响因子：
6
通讯作者：
Zhao, Baofeng
中科院分区：
文献类型：
--
作者：
Yang, Shuangxia;Zhang, Xiaodong;Zhao, Baofeng
以层状双氢氧化物（LDHs）为前驱体制备Fe/CaO催化剂，在两段固定床反应系统中进一步优化生物质催化热解制备富氢合成气的操作条件。考察了催化剂焙烧温度和床层温度对合成气组成和产率的影响。采用XRD、SEM、BET、H-2-TPR和CO2-TPD等表征手段对Fe/CaO催化剂进行了表征。结果表明，在600 ℃的温和温度下合成的催化剂具有较好的富氢合成气性能，这可能是由于其形貌均匀、粒径较小、上级还原性和较强的CO2吸收能力。此外，较高的反应温度有利于反应速率的提高，有利于重质有机分子的二次裂解和重整反应，合成气产率最高可达63.0wt.%和使用在600 ℃煅烧的Fe/CaO催化剂在800 ℃的催化温度下获得的172 mL/g生物质的H-2产率。然而，H-2/CO比仅处于0.99的次优水平，因为在较高催化温度下CaCO 3的分解释放CO2并抑制水煤气变换反应以产生更多的H-2。
This study aimed to further optimize the operating conditions to produce hydrogen-enriched syngas from the catalytic pyrolysis of biomass in a two-stage fixed-bed reaction system with the Fe/CaO catalyst derived from layered double hydroxides (LDHs) precursor. Specifically, the effects of catalyst calcination temperature and catalytic bed temperature on the composition and yield of syngas were investigated. Various characterization techniques such as XRD, SEM, BET, H-2-TPR and CO2-TPD were employed to thoroughly characterize the Fe/CaO catalysts both before and after the catalytic reaction. It was found that the catalyst synthesized at a mild temperature of 600 degrees C performed the best in producing hydrogen-enriched syngas, probably because of its uniform morphology, smaller particle size, superior reducibility and stronger CO2 absorption ability. In addition, higher temperature was found to benefit the syngas production due to the acceleration of reaction rate and promotion of secondary cracking and reforming reactions of heavy organic molecules with the maximum syngas yield of 63.0 wt.% and H-2 yield of 172 mL/g biomass obtained at catalytic temperature of 800 degrees C using Fe/CaO catalyst calcined at 600 degrees C. Nevertheless, the H-2/CO ratio was only at a suboptimal level of 0.99 because the decomposition of CaCO3 at higher catalytic temperature released CO2 and suppressed the water gas shift reaction to produce more H-2.