The functionalities of Pt/γ-Al₂O₃ catalysts in simultaneous HDS and HDA reactions

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• 作者：V.G. Baldovino-Medrano ; Sonia A. Giraldo ; Aristó ; bulo Centeno
• 关键词：HDS ; HDA ; HYD pathway ; Pt/γ ; -Al₂O₃ ; Activation procedure
• 刊名：Fuel
• 出版年：2008
• 期刊代码：33_00162361
• 类别：ce
• 出版时间：August 2008
• 卷：87
• 期：10-11
• 页码：1917-1926
• 文件大小：230 K

摘要

A Pt/γ-Al₂O₃ catalyst was tested in simultaneous hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of naphthalene reactions. Samples of it were subjected to different pretreatments: reduction, reduction–sulfidation, sulfidation with pure H₂S and non-activation. The reduced catalyst presented the best performance, even comparable to that of Co(Ni)Mo catalysts. All catalyst samples were selective to the HDS reaction over HDA, and to the direct desulfurization pathway of dibenzothiophene HDS over the hydrogenation reaction pathway of HDS. The effect of H₂S partial pressure on the functionalities of the reduced Pt/γ-Al₂O₃ catalyst was studied. The results showed that an increase in H₂S partial pressure does not cause poisoning, but an inhibition effect, without changing the catalyst selectivity. Accordingly, the activity trends were ascribed to adsorption differences between the different reactive molecules over the same catalytic active site. TPR characterization along with a thermodynamics analysis showed that the active phase of reduced Pt/γ-Al₂O₃ is constituted by Pt⁰ particles. However, presulfidation of the catalyst leads to a mixture of PtS and Pt⁰ which has a negative effect on the catalytic performance without changing catalyst functionalities.