Effect of the addition of catalysts in solid state reactions : Akinetic study on the change of reaction pathways for its utilization

添加催化剂对固相反应的影响：反应途径变化的动力学研究及其利用

• 批准号: 13650842
• 负责人: YOSHIDA Noritetsu
• 金额: $ 1.98万
• 依托单位: Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650842/
• 关键词: Solid-State Reaction; Addition of Catalysts; Kinetic Study; Group VIII Metals; Hydrogen Formation; Flow Reactor; Environmental Problem; 金属触媒; 酸化カルシウム; メタン水蒸気改質; 硝酸カルシウム; 分解反応; VIII族金属媒体; メタンの水蒸気改質

This work aims to find out and to investigate solid-stale reactions whose pathways can be converted by the addition of catalysts into those producing useful materials or effectively contributing towards the solution of environmental problems. We initiated a project to investigate at first the opposing reactions involving CaCO_3-CaO solid-state conversion, since we had already confirmed that metal-catalyzed hydrogenation of CaCO_3, gives CH_4, as a gaseous product, instead of CO without catalysts. It was the reverse reaction (CaO+2H_2O+CH_4 → CaCO_3+4H_2) that has been extensively studied here, because of the possibility as a promising process to give pure hydrogen.Preliminary experiments to confirm actual occurrence of the reverse reaction with Group VIII metals present were followed by a detailed kinetic study with solid samples in the form of Metal/CaO and Metal/CaCO_3. The results so far obtained are as follows : (1) Pathway for the reverse reaction is quite different from one for t … More he forward reaction to form CH_4. Namely, the reverse reaction proceeds via two-step mechanism consisting of steam-reforming of CH_4 on metal surfaces and subsequent process for absorbing CO_2 by CaO, while the forward reaction via one-step mechanism involving direct interaction of solid CaCO_3 with H atoms dissociated on metal surfaces. (2) Such a mechanistic difference results in large difference in a poisoning effect of Clions, which is negligible in the forward reaction but severe in the reverse one. (3) Catalytic activity of metals decreases in the order : Rh,Ir> Pt,Pd> Ni.Afixed-bed flow reactor equipped with QMS and GC were constructed in the end of the first year to carry out another project for elucidating dynamic behavior of C0_2 during the steam reforming of CH_4 on Metal/CaO at high temperatures (600℃), where CO_2 cannot be absorbed in the bulk of CaO at all. For this purpose, however, the above conventional apparatus was not suitable, and hence converted into a pulse-reactor. Detailed study have never been carried out yet, using this reactor, except for some fundamental results for the temperature-programmed decomposition of Ca(NO_3)_2 in the presence of Pt. Less

这项工作的目的是找出并研究固态反应，这些反应的路径可以通过添加催化剂转换为产生有用材料或有效地有助于解决环境问题的反应。我们首先启动了一个研究CaCO_3-CaO固相转化的相反反应的项目，因为我们已经证实，在没有催化剂的情况下，金属催化的CaCO_3加氢生成的是气态产物CH4，而不是CO。以CaO+2H_2O+CH_4-→-CaCO_3+4H_2为研究对象的逆反应是一种很有前景的制氢方法。在对第VIII族金属实际发生逆反应的初步实验基础上，用金属/CaO和金属/CaCO_3两种固体样品进行了详细的动力学研究。迄今所得结果如下：(1)该逆反应的途径与t-…有很大不同即反向反应通过两步反应进行，即CH4在金属表面的水蒸气重整和后续的CaO吸收CO_2的过程，而正向反应是通过固体CaCO3与金属表面解离的H原子直接相互作用的一步反应进行的。(2)这种机理上的差异导致了CLIONS毒化效应的巨大差异，这种差异在正向反应中可以忽略，而在反向反应中则很严重。(3)金属的催化活性大小顺序为：Rh，Ir&Gt；Pt，Pd&Gt；Ni.在第一年末建造了一个装有QMS和GC的固定床流动反应器，用于研究高温(600℃)下CO_2在金属/CaO上水蒸气重整过程中CO_2的动态行为，其中CO_2完全不能被CaO整体吸附。然而，为了达到这个目的，上述常规装置并不适用，因此改装成了脉冲反应堆。除了在铂存在下对Ca(NO3)2进行程序升温分解的一些基本结果外，利用该反应器还没有进行过详细的研究。较少

项目成果

Norihiro Chikazawa: "Kinetic study of metal-catalyzed reaction of solid calcium oxide with gas mixture of methane and water vapor"Catalysis Letters. 77巻・1号. 63-66 (2001)

Norihiro Chikazawa：“固体氧化钙与甲烷和水蒸气的气体混合物的金属催化反应的动力学研究”，《催化快报》，第 77 卷，第 1. 63-66 期（2001 年）。

N.Chikazawa, M.Suehiro, and N.Yoshida: "Anomalous Progress of Ir-Catalyzed Reaction of Solid CaO with Gas Mixtures of Methane and Water Vapor"Catalysis Letters. in press. (2003)

N.Chikazawa、M.Suehiro 和 N.Yoshida：“固体 CaO 与甲烷和水蒸气的气体混合物的 Ir 催化反应的异常进展”催化快报。

N.Chikazawa, Y.Fujisaki, Y.Sato, M.Suehiro, N.Yoshida: "Kinetic Study of Metal-Catalyzed Reaction of Solid Calcium Oxide with Gas Mixtures of Methane and Water Vapor"Catalysis Letters. Vol.77. 63-66 (2001)

N.Chikazawa、Y.Fujisaki、Y.Sato、M.Suehiro、N.Yoshida：“固体氧化钙与甲烷和水蒸气的气体混合物的金属催化反应的动力学研究”催化快报。

N.Chikazawa, M.Suehiro, N.Yoshida: "Anomalous Progress of Ir-Catalyzed Reaction of Solid CaO with Gas Mixtures of Methane and Water Vapor"Catalysis Letters. (印刷中). (2003)

N.Chikazawa、M.Suehiro、N.Yoshida：“固体 CaO 与甲烷和水蒸气的气体混合物的 Ir 催化反应的异常进展”催化快报（2003 年出版）。

N.Chikazawa, Y.Fujisaki, Y.Sato, M.Suehiro, and N.Yoshida: "Kinetic Study of Metal-Catalyzed Reaction of Solid Calcium Oxide with Gas Mixtures of Methane and Water Vapor to Form Hydrogen"Catalysis Letters. 77. 63 (2001)

N.Chikazawa、Y.Fujisaki、Y.Sato、M.Suehiro 和 N.Yoshida：“固体氧化钙与甲烷和水蒸气的气体混合物形成氢气的金属催化反应的动力学研究”催化快报。