Methanol Steam Reforming MSR

Several studies are available addressing the mechanism and kinetics of the MSR reaction over Cu-based catalysts [115-121], There is agreement nowadays that C02 is a direct product of the MSR reaction and not of a sequence of methanol decomposition and WGS reactions. The main source of CO is the rWGS reaction taking place as a secondary reaction after MSR. Frank et al. [121] presented a 

The question as to what is the active site of Cu-based catalysts in MSR is still unclear and debated in the literature. Similar to the methanol synthesis reaction, either metallic Cu° sites, oxidized Cu+ sites dispersed on the oxide component or at the Cu-oxide interface, or a combination of both kinds of sites are thought to contribute to the active ensembles at the Cu surface. Furthermore, the oxidic surface of the refractory component may take part in the catalytic reaction and provide adsorption sites for the oxygenate-bonded species [126], whereas hydrogen is probably adsorbed at the metallic Cu surface. Similar to methanol synthesis, factors intrinsic to the Cu phase also contribute to the MSR activity in addition to SACu- There are two major views discussed in the literature relating these intrinsic factors either to the variable oxidation state of Cu, in particular to the in situ adjustment of the Cu°/Cu+ ratio at the catalyst s surface [102, 107, 127 132], or to the defect structure and varying 

Palo et al. [18] found surprisingly low carbon monoxide concentrations, not higher than 1.2%, at reaction temperatures as high as 375 °C with their proprietary catalyst. 

This was ascribed to the short residence times applied (50-100 ms). Under these conditions, assuming the reaction mechanism proposed by Takahashi et al. shown above, carbon monoxide could only be formed by the reverse water-gas shift reaction, which is known to be slower than the reforming reaction. This is the case especially for catalyst systems with low activity towards water-gas shift. Holladay et al. [19] compared the performance of the same proprietary catalyst with that of a Cu/Zn catalyst which produced a higher carbon monoxide concentration of 3.1% in the reformate. 

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Mann, Thurgood, and coworkers—Langmuir-Hinshelwood kinetic model for methanol steam reforming and WGS over Cu/Zn. Mann et al.335 published a complex Langmuir-Hinshelwood model for CuO/ZnO catalysts based on what one would encounter for a methanol steam reformer (MSR) for fuel cell applications. The water-gas shift rate, containing all MSR terms, was determined to be ... 

Methanol synthesis from C02 (Equation [1]) and CO (Equation [2]) is mildly exothermic and results in volumetric contraction. Methanol steam reforming (MSR) refers to the inverse of reaction (1), and the inverse of reaction (2) is conventionally referred to as methanol decomposition - an undesired side reaction to MSR. The slightly endothermic reverse water-gas shift (rWGS) reaction (Equation [3]) occurs as a side reaction to methanol synthesis and MSR. According to Le Chatelier s principle, high pressures and low temperatures would favor methanol synthesis, whereas the opposite set of conditions would favor MSR and methanol decomposition. It should be noted that any two of the three reactions are linearly independent and therefore sufficient in describing the compositions of equilibrated mixtures. 

Methanol Steam Reforming 1 [MSR 1] Electrically Heated Serpentine Channel Chip-like Reactor... 

Methanol Steam Reforming 3 [MSR 3] Electrically Heated Stack-like Reactor... 

Methanol Steam Reforming 6 [MSR 6] Electrically Heated Screening Reactor... 

Pfeifer et al. [23] focused on Pd/PdZn/ZnO systems for methanol steam reforming. In the same reactor ([MSR 3]) the formation of a Pd/Zn alloy at higher... 

The [MSR 6] reactor type (see below) was applied for methanol steam reforming over Cu/Ce02/Al203 catalysts by Men et al. [34, 35], Wash coating of the alumina was performed, followed by subsequent impregnation steps with ceria and copper salt solutions. At 250 °C reaction temperature and a water/methanol molar ratio of 0.9, the copper/ceria atomic ratio was varied from 0 to 0.9, revealing the lowest conversion for pure ceria and a sharp maximum for a ratio of 0.1 (see Figure 2.13). 

MRT MS MSR Micro reaction technology Mass spectrometry Methanol steam reforming... 

Figure 6.4 Numbers of publications of Methanol steam reforming reaction (MSR) in membrane reactors (MRs) throughout the years.

An alternative to filling or coating with a catalyst layer the microcharmels, with the related problems of avoiding maldistribution, which leads to a broad residence time distribution (RTD), is to create the microchannels between the void space left from a close packing of parallel filaments or wires. This novel MSR concept has been applied for the oxidative steam reforming of methanol [173]. Thin linear metallic wires, with diameters in the millimeter range, were close packed and introduced into a macro tubular reactor. The catalyst layer was grown on the external surface of these wires by thermal treatment. 

Among several studies reporting catalyst development in MSRs for the steam reforming of methanol over well-known catalysts such as Cu/ZnO and Pd/ZnO [16, 54-56],... 

SRM based on MSRs has acquired an increasing interest due to system compactness with portable apphcations for fuel cells, which could be apphed on auxiliary power imits (APUs). Moreover, catalytic autothermal reforming of methanol has also been considered since it offers some advantages over endothermic steam reforming and exothermic partial oxidation [67]. 

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