Steam catalytic cracking is an alternative method to produce light tar fractions from coal tar. In this study, Mn−Ce modified Fe₂O₃ catalysts were prepared by impregnation method, and used for steam catalytic cracking of coal tar in a fixed‐bed reactor at 550 °C and atmospheric pressure. The results showed that the catalyst Fe80Mn15Ce5 (Fe/Mn/Ce mole ratio 80/15/5) exhibits the best performance in terms of highest light tar yield being 67.6 wt.%. Moreover, the decrease of weight hourly space velocity (WHSV) can further increase the pitch conversion and the light tar content. As a result, when the WHSV is 0.65 h⁻¹, the light tar yield reaches 71.6 wt.% on Fe80Mn15Ce5. The structural variations of catalysts were characterized by several analytical techniques to reveal the improved catalytic performance. It is shown that the impregnation of MnO_x improves the structural stability of Fe₂O₃ due to the formation of Fe−Mn solid solution, while the load of CeO_x activates lattice oxygen. As a result, more active oxygen species generating from steam dissociation can participate in the catalytic upgrading of coal tar.

中文翻译：

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用于煤焦油蒸汽催化裂化的Ce-Mn / Fe2O3催化剂的制备

蒸汽催化裂化是从煤焦油生产轻质焦油馏分的另一种方法。在这项研究中，通过浸渍法制备了Mn-Ce改性的Fe ₂ O ₃催化剂，并用于在550°C和大气压下在固定床反应器中对煤焦油进行蒸汽催化裂化。结果表明，就最高轻焦油产率为67.6重量％而言，催化剂Fe80Mn15Ce5（Fe / Mn / Ce摩尔比为80/15/5）表现出最佳性能。而且，重量时空速度（WHSV）的降低可以进一步增加沥青转化率和轻焦油含量。结果，当WHSV为0.65 h ^-1时，Fe80Mn15Ce5的轻焦油收率达到71.6 wt。％。通过几种分析技术表征了催化剂的结构变化，以揭示改进的催化性能。结果表明，由于Fe-Mn固溶体的形成，MnO _x的浸渍提高了Fe ₂ O ₃的结构稳定性，而CeO _x的负载则激活了晶格氧。结果，由蒸汽分解产生的更多活性氧可以参与煤焦油的催化提质。