Methanol steam reforming component

DME hydration occurs over acid catalysts, whereas the methanol steam reforming reaction proceeds over metal catalysts. Consequently, DME steam reforming requires a multi-component catalyst. Two approaches have been proposed in the literature (a) physical mixtures of a DME hydrolysis catalyst and a methanol steam reforming catalyst (b) supported catalysts that combine the DME hydrolysis and methanol steam reforming components into a single catalyst. 

Shah and Besser presented results from their development work that was aimed at a 20-Wd methanol fuel processor/fuel cell system [436]. The principle layout of the device consisted of a methanol steam reformer, preferential oxidation, a catalytic afterburner and an evaporator The basic process and design parameters are summarised in Table 9.3. Nevertheless, it is obvious that the size of the steam reformer exceeded by far the size of all other components. The weight hourly space... 

Catalysts based on copper/zinc mixed oxides are of great importance for industrial scale catalytic processes like low pressure methanol formation from synthesis gas and steam reforming of methanol yielding H2 and CO2. The commercially available catalyst for both reactions is the ternary system Cu-Zn0/Al20s [5], In consequence of its success, the Cu-ZnO system has prompted a great deal of fundamental work devoted to clarify either the role played by each component and the nature of the active site. 

When hydrogen is produced by steam reforming of methanol or hydrocarbons, CO is the second-largest byproduct component (about 1 vol %) after CO2- In application to PEFC, to remove CO to a concentration of 100 ppm, CO should be reduced to methane or oxidized to CO2. Oxidation is advantageous because it potentially consumes less hydrogen. 

Baddour et al. [26] in their simulation of the TVA ammonia-synthesis converter, already discussed in Sec. 11.5.e, found that in steady-state operation the temperature difference between the gas and the solid at the top, where the rate of reaction is a maximum, amounts to only 2.3°C and decreases as the gas proceeds down the reactor to a value of 0.4°C at the outlet. In the methanol reactor simulated in Sec. 11.9.b the difference between gas and solid temperature is of the order of 1 C. This may not be so with highly exothermic and fast reactions involving a component of the catalyst as encountered in the reoxidation of Fe and Ni catalysts used in ammonia synthesis and steam reforming plants or involving material deposited on the catalyst, coke for example. 

A prototype for a methanol reforming silicon reactor was designed at Lehigh University [11,12,31]. Their microreaction system, made of silicon wafers, consisted of four main components a mixer/vaporizer of methanol and water, a catalytic steam reformer with a copper catalyst, the combined water gas shift reactor-membrane (as mentioned before) and integrated resistive heaters, sensors and control electronics. The reformer was tested with a stainless-steel housing. The authors reported a conversion of 90% for methanol, which corresponds to a power output of 15 W. 

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