Steam reforming mechanism

Steam Reformings of Natural Gas. This route accounts for at least 80% of the world s methanol capacity. A steam reformer is essentially a process furnace in which the endothermic heat of reaction is provided by firing across tubes filled with a nickel-based catalyst through which the reactants flow. Several mechanical variants are available (see Ammonia). 

We have shown that the steam reforming of propane may be adequately described by LH mechanism involving different adsorption sites for steam and hydrocarbon. The associated model satisfied both statistical compliance and the BMV thermodynamic criterion. 

The catalytic steam-reforming process of methanol on Cu/ZnO/Ab03 catalyst primarily produces hydrogen and carbon dioxide. In addition, the minor quantities of carbon monoxide are also produced. This mechanism is explained in terms of parallel reactions [11]. 

In a number of publications, Rostrup-Nielsen discusses different mechanism of methane steam reforming over Ni catalysts [17]. The proposed simplified reaction sequence for reforming of methane is as follows ... 

No other products were detected in the gas phase. The amount of H2 produced from 85 pmol of m-C16H34 was 4.14 mmol, which is close to the stoichiometric value. One can note that reaction 2.72 stoichiometry resembles that of steam reforming of hexadecane. The authors proposed the following mechanism, which involves the initial generation of active species holes (p+) in the valence band and electrons (e ) in the conduction band of... 

Takahashi, K. Takezawa, N. Kobayashi, H., The mechanism of steam reforming of vehicles. Applied Catalysis 1982, 2, 363-366. 

This review analyzed the chemistry involved, thermodynamics, catalysts used, reaction pathways and mechanisms of various reforming techniques reported for the conversion of ethanol into H2-rich gas. The known reforming processes are broadly classified into three categories, namely steam reforming of ethanol (SRE), partial oxidation of ethanol (POE) and oxidative steam reforming (OSR)/autothermal reforming of ethanol. All these reactions are thermodynamically favorable even at lower temperatures, above 200 °C. 

Currently, low-temperature CO oxidation over Au catalysts is practically important in connection with air quality control (CO removal from air) and the purification of hydrogen produced by steam reforming of methanol or hydrocarbons for polymer electrolyte fuel cells (CO removal from H2). Moreover, reaction mechanisms for CO oxidation have been studied most extensively and intensively throughout the history of catalysis research. Many reviews [4,19-28] and highlight articles [12, 29, 30] have been published on CO oxidation over catalysts. This chapter summarizes of the state of art of low temperature CO oxidation in air and in H2 over supported Au NPs. The objective is also to overview of mechanisms of CO oxidation catalyzed by Au. 

Two reaction mechanisms for partial propane oxidation exist in the literature. One of them proposes that the reaction starts with catalytic combustion followed by reactions of a lower rate, namely steam reforming, C02 reforming and water-gas shift [54], Aartun et al. [55] investigated both reactions. The other mechanism proposes that the partial oxidation reaction occurs directly at very short residence times [56], which are easier to achieve in the micro channels. 

Other Commercial Catalyst Formulations. Many papers and patents have recently appeared which are also addressed to the problem of maintaining mechanical strength as well as activity and chemical stability during steam reforming and methanation. Hence, only selected examples will be given in the following paragraphs. 

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