Role of nickel and vanadium over USY and RE-USY coke formation
Role of nickel and vanadium over USY and RE-USY coke formation
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DOI：
10.1016/j.apcata.2006.09.004
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发表时间：
2006-11-23
影响因子：
5.5
通讯作者：
Pereira, Marcelo M.
中科院分区：
文献类型：
--
作者：
Escobar, Alyne S.;Pinto, Fernanda V.;Pereira, Marcelo M.
本文探讨了镍和钒氧化态在 USY 和 RE-USY 沸石上的环己烷模型裂解反应焦炭形成中的作用。由于镍和/或钒污染金属的存在，USY 和 RE-USY 两种沸石的焦炭产率均有所增加。当先前未应用蒸汽失活时，负载有 Ni 和 V 的 USY 表现出与单独负载有 Ni 或 V 的 USY 大致相同的还原性。然而，与明显负载 Ni 或 V 相比，负载 Ni 和 V 的 RE-USY 或 USY 的焦炭形成减少了 2 倍。该因素既不受氧化/还原处理的影响，也不受稀土存在的影响。氧化处理后，钒是焦炭形成的主要原因。对于V-USY催化剂，还原后焦炭产率增加了2.7倍，而对于Ni-USY催化剂，焦炭产率增加了13倍。对于RE-USY催化剂，焦炭的形成在钒位点上受到强烈抑制，而在镍位点上则得到促进。这些结果表明，沸石酸性位点上焦炭的形成受到 Ni-V、Ni-RE 和 V-RE 元素之间多组分相互作用的影响。 (c) 2006 Elsevier B.V. 保留所有权利。
The present paper approaches the role of nickel and vanadium oxidation states in the coke formation from cyclohexane model cracking reaction over USY and RE-USY zeolites. The coke yield increased for both zeolites, USY and RE-USY, due to the presence of nickel and/or vanadium contaminant metals. USY loaded with Ni and V presented about the same reducibility of USY loaded distinctly with Ni or V, when steam deactivation is not applied previously. However, coke formation decreased by a factor of 2 for RE-USY or USY loaded with Ni and V when compared to Ni or V loaded distinctly. This factor was affected neither by oxidation/reduction treatments, nor by rare-earths presence. After oxidation treatment vanadium is the principal responsible for coke formation. For V-USY catalyst the coke yield increase by a factor of 2.7 after reduction, while for Ni-USY catalyst coke yield increase by a factor of 13. For the RE-USY catalyst, the coke formation is strongly inhibited on vanadium sites and promoted on nickel sites. These results suggest that the coke formation on the zeolite acidic sites is influenced by multicomponent interaction between Ni-V, Ni-RE and V-RE elements. (c) 2006 Elsevier B.V. All rights reserved.