The paper presents an investigation on the catalytic activity for the ethanol steam reforming of Co 3 O 4 oxidized, reduced and supported on MgO, and of CoO in MgO solid solution. Only samples containing metallic cobalt are found to be active for reforming reaction. H 2 -TPR characterization of aged samples shows that reaction mixture oxidizes a small fraction of metallic cobalt to Co +2 . A distinct role of Co +2 and Co 0 in the reaction is enlightened.

Cobalt oxide Co(3)O(4) is prepared according to several methods i.e. oxalate decomposition (CoAO), surfactant-assisted precipitation (CoCTAB), sol-gel technique (CoSG) and polymer combustion (CoPVA). The solids are characterized by XRD, FTIR, TPR and TEM analysis. The method via oxalate decomposition (CoAO) appears as that giving the smallest particles nanostructured with an almost monomodal distribution, whereas the CoPVA needs to be calcined at the highest temperature in order to have pure Co(3)O(4). As a consequence on CoPVA the largest particle size is found. The reducibility by H(2) of cobalt oxide particles having the smallest (CoAO) and the largest particle size (CoPVA) is found to depend on the particle dimensions and, where the distribution is monomodal, the reduction steps Co(3)O(4) -> CoO -> Co appear clearly distinct and the temperatures relative to the two reduction steps are well beyond those monitored on microprepared oxide, where only a gross and unique reduction peak is envisaged

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The wet limestone flue gas desulfurization process, and more specifically absorption of SO2 limestone suspensions, was studied. Experiments of SO2 absorption were carried out using a bubbling reactor with a mixture of sulfur dioxide and nitrogen in the gas phase and an aqueous limestone suspension in the liquid phase. The SO2 absorption rate was measured at different compositions of both gas and liquid phases and at different gas flow rates and agitator speeds. A model based on the film theory was proposed to describe liquid-side mass transfer. It was assumed that the liquid-phase diffusional resistance is concentrated in a layer, the thickness of which depends on fluid dynamics, but is independent of the nature of the reactions taking place. The equations considered by the model describe conditions of thermodynamic equilibrium as well as material and electrical balances and use the experimentally determined gas- and liquid-side mass-transfer coefficients, rather than empirical parameters. Model calculations and experimental results were compared, and a good consistency was found. Eventually the model was used to evaluate the absorption enhancement factor as a function of gas- and liquid-phase composition.