Abstract Efficient removal of tar at gas outlet is a challenge during COREX ironmaking process. The differences between fresh and reduced LaNi1-xFexO3 perovskite were investigated via catalytic cracking of coal tar at 700 °C. The total gas yield of fresh catalysts is generally higher than that of reduced ones. The reduced catalyst produced more tar and carbon deposition. While the fresh LaNi0.8Fe0.2O3 gave the highest total gas yield (34.8 mmol/gcoal) and H2 yield (20.9 mmol/gcoal), and the lowest tar production (0.05%) and carbon deposition (10.9%). The perovskite structure was destroyed after reduction and the metal in perovskite was reduced to load on the catalyst surface. Partial oxidation which produces CO and H2 mainly occurs in the catalysis of reduced perovskite. Complete oxidation which generates CO2 and water is the major catalytic route for fresh perovskite. Oxygen in perovskite will transfer from the bulk to the surface. Water in the product supplements oxygen for the perovskite to construct an oxygen transition cycle which can maintain the catalyst activity. Tar is decomposed by the oxygen in fresh perovskite structure. The high nickel content in perovskite could promote the oxidation of tar.

中文翻译：

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煤焦油在新鲜和还原的 LaNi1-xFexO3 钙钛矿上催化裂化的机理

摘要 在出气口高效去除焦油是COREX炼铁过程中的一个挑战。通过煤焦油在 700 °C 的催化裂化，研究了新鲜和还原的 LaNi1-xFexO3 钙钛矿之间的差异。新鲜催化剂的总产气率通常高于还原催化剂的总产气率。还原的催化剂产生更多的焦油和碳沉积。而新鲜的 LaNi0.8Fe0.2O3 的总气体产率 (34.8 mmol/gcoal) 和 H2 产率 (20.9 mmol/gcoal) 最高，焦油产量 (0.05%) 和积碳 (10.9%) 最低。还原后钙钛矿结构被破坏，钙钛矿中的金属被还原负载到催化剂表面。产生 CO 和 H2 的部分氧化主要发生在还原钙钛矿的催化中。产生二氧化碳和水的完全氧化是新鲜钙钛矿的主要催化途径。钙钛矿中的氧气会从本体转移到表面。产品中的水为钙钛矿补充氧气，构建氧转变循环，保持催化剂活性。焦油被新鲜钙钛矿结构中的氧分解。钙钛矿中的高镍含量可以促进焦油的氧化。