Kinetic study of ethanol steam reforming over a commercial nickel−magnesia−alumina (Ni/MgO/Al2O3) catalyst was conducted in a fixed-bed reactor 15 mm in diameter. The effects of temperature (673−873 K), molar ratio of steam to ethanol in the feed (in the range of 3:1 to 18:1), feed flow rate (W/F EtOH = 46.2−555.25 g-cat min/mol), catalyst particle size (2.25−0.75 mm), and time-on-stream study was studied. Maximum conversion (>95%) was obtained at 873 K, with a molar ratio of steam to ethanol of 12:1 and a W/F EtOH value of >185 g-cat min/mol at atmospheric pressure. A maximum yield of 3.0 moles of hydrogen per mole of ethanol fed was obtained at a temperature of 873 K, a steam-to-ethanol molar feed ratio of 12:1, and a W/F EtOH value of >110 g-cat min/mol. The acquired data was fitted to a power-law kinetic model and the kinetic parameters were evaluated. The activation energy was determined to be 23 kJ/mol. The average absolute deviation (AAD) for the predicted rates of reaction was determined to be 10.2%. The work also tested the feasibility of using the Eley−Rideal mechanism proposed in the literature and concludes that a more-elaborate scheme of reactions is necessary to describe the complex reactions that occur during the steam reforming process. A considerable amount of coke formation was observed during the process; yet, the catalyst showed a negligible loss of activity, exhibiting the feasibility of using this catalyst for ethanol steam reforming. In an attempt to reduce this coke formation, it is suggested that the process may be performed in the presence of hydrogen gas.

In this study, the mass transfer efficiencies of a novel horizontal rotating packed (h-RPB) bed and the conventional disc-type rotating biological contactor (RBC) were studied at four speeds and seven submergences. Pall rings of two different sizes (25, 38 mm), superintalox saddles and a wiremesh spiral bundle were used as packings in the h-RPB. Volumetric gas-liquid mass transfer coefficients were determined by unsteady state absorption of atmospheric oxygen in de-aerated water. Power consumption per unit liquid volume has been found for all geometries tested. The oxygen transfer efficiency values for the h-RPB were found to be 2-5 kg kWh −1 and for the disc RBC were found to be 1-2 kg kWh −1 . The performance of the h-RPB was also compared with other gas-liquid contactors such as surface aerators. The study proves that the h-RPB is a energy efficient alternative to conventional contactors.

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