De–SO_x additives based on mixed oxides derived from Mg,Al-hydrotalcite-like compounds containing Fe, Cu, Co or Cr

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• 作者：Carla Maria Salerno Polato ; Cristiane Assumpç ; ã ; o Henriques ; Alex ; re Carlos Camacho Rodrigues ; José ; Luiz Fontes Monteiro
• 关键词：SO_x emission control ; Sulfur-transfer catalysts ; FCC unit ; Mg ; Al-mixed oxides ; Fe ; Cu ; Co ; Cr
• 刊名：Catalysis Today
• 出版年：2008
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：April-June 2008
• 卷：133-135
• 期：Complete
• 页码：534-540
• 文件大小：615 K

摘要

Mg,Al-hydrotalcite-like compounds (HTLCs) with an M³⁺/(M²⁺ + M³⁺) molar ratio equal to 0.25 in which Mg or Al were partially replaced by Cu, Co, Cr or Fe were prepared and used as precursors for different mixed oxides (MO): Cu–MO, Co–MO, Cr–MO or Fe–MO. These materials were evaluated for SO_x removal under conditions similar to those found in the fluid catalytic cracking (FCC) regenerator. The following order of catalytic activity for SO_x uptake was observed: Cu–MO > Co–MO > Fe–MO > Cr–MO. The regeneration of the sulfated additives was also studied and the results showed that the composition of the reductive stream influenced the regeneration profiles, the total quantity of sulfur released, and the reduction products distribution, in a specific way for each sample. These results could be related to the nature of the reducing agent and to the fact that the thermal stability and the reducibility of the sulfates are significantly affected by the metal with redox properties present in the additive.