Oxidative methanol steam reforming

Sensor for H2 oxidation Methanol steam reforming Methanol steam reforming Water gas shift... 

Oxidative methanol steam reforming conversion versus reaction temperature. 

Figure 23. Methanol—steam reformers, heat exchangers, combustor, and selective oxidation reactors the body materiai was stainless steel. ...

In a later study, Pfeifer et al. [30] prepared Pd/Zn catalysts by both pre- and postimpregnation of wash-coated zinc oxide particles with palladium and compared their performance in methanol steam reforming. The catalytic performance of the samples was tested at a 250 °C reaction temperature, 3 bar pressure, a S/C ratio of two and 250 ms residence time. The WHSV amounted as 0.3 Ndm3 (min gcat) 1. The thickness of the coatings was calculated to 20 pm. The formation of the PdZn alloy was proven to occur at temperatures exceeding 200 °C by XRD measurements. 

Bravo et al. [29] dealt with the coating of a commercial CuO/ZnO catalyst on quartz and fused-silica capillaries for future application in micro channels. The catalyst was mixed with boehmite as binder and water at a mass ratio of44 11 100. The boehmite was treated with hydrochloric or nitric acid before. The capillaries were pretreated with a hot sulfuric acid/solid oxidation step before coating. The capillaries were filled with the catalyst/binder suspension and then cleared with air. In this way, catalyst coatings up to 25 pm thick were obtained. The coatings were applied to methanol steam reforming (see Section 2.4.1). 

Wash coats made of various source aluminas were prepared by applying this procedure (Figure 2.96) [147]. The catalysts obtained after subsequent impregnation were applied to methanol steam reforming [25, 28], propane steam reforming [52], water-gas shift [84] and preferential oxidation [89], to name but a few reaction systems. 

Hydrogenation of furan, 2,3-dihy-drofuran, silvan, and furfural Methanol steam reforming Coupling of dehydrogenation of isoamylenes and hydrodemethyN ation of toluene or oxidation of hydrogen ... 

Partial oxidation of propane (Coating characterization) Partial oxidation of propane Selective catalytic reduction of NOx (Coating characterization) Water gas shift Methane steam reforming Methanol steam reforming Schwarz et al. [178] Roumanie et al. [179] Pennemann et al. [183] Ercoli et al. [184] Stefanescu et al. [181] Germani et al. [177] Tonkovich et al. [182] Yu et al. [185]... 

Methanol steam reforming Catalytic combustion Partial oxidation of isoprene... 

Reuse et al. [16] combined endothermic methanol steam reforming with exothermic methanol combustion in a plate heat exchanger reactor, which was composed of a stack of 40 foils (Figure 24.5). Each foil carried 34 S-shaped channels. Cu/ZnO catalyst from Siid-Chemie (G-66MR) was coated into the channel system for the steam reforming reaction. Cobalt oxide catalyst served for the combustion reaction. The reactor was operated in co-current mode. The steam reformer was operated at a S/C ratio of 1.2. At reaction temperatures between 250 and 260 °C, more than 95% conversion and more than 95% carbon dioxide selectivity were achieved. 

Men et al. reported the operation of a small-scale bread-board methanol fuel processor composed of electrically heated reactors [15]. A methanol steam reformer, two-stage preferential oxidation reactors and a catalytic afterburner were switched in series. A fuel cell equipped with a reformate-tolerant membrane, which had a 20 W nominal power output, was connected to the fuel processor and operated for about 100 h. 

Shah and Besser presented results from their development work targeted at a 20 Wei methanol fuel processor-fuel cell system [66]. The layout of the system consisted of a methanol steam reformer, preferential oxidation, a catalytic afterburner and an evaporator. Vacuum packaging was the insulation strategy for the device, which is in line with other small-scale systems described above. A micro fixed-bed steam reformer coupled to a preferential oxidation reactor was then developed by the same group with a theoretical power output of 0.65 W. 

An exception in terms of catalysts is the catalytic partial oxidation or OSR of methanol due to the low reaction temperature required. Copper [25, 32-36] and palladium-zinc ahoy [36-38] have been proven to give high selectivities and space-time yields. For the latter system, the palladium forms an alloy with the zinc oxide support under reducing conditions above 300 °C and is stable under the reaction conditions of methanol steam reforming [39]. However, the stability of the ahoy under CPO has not been proven so far by X-ray diflraction after exposure to reaction conditions. 

From our own experience, series of various steels (for low and high temperature) were tested under reaction conditions (for example, for methane and methanol steam reforming and partial oxidation to formaldehyde) either as raw materials or after protective layer coating, including the soldering/brazing materials used for assembly. 

Also under oxidizing conditions, like the partial oxidation of methanol to hydrogen, water, and CO2, intermetallic compounds can be formed. As in the case of methanol steam reforming over Pd/ZnO, the intermetallic compound ZnPd is part of the catalytic system Pd-Zn/Al203 under these conditions (125). The observation of intermetallic compounds is not limited to oxidation reactions involving methanol. Also in the oxidation of aldoses such as lactose and glucose over... 

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