The mechanism of SO2 oxidn.-adsorption to form regenerable sulfates on a Cu-Al2O3 sorbent-catalyst was detd. The studies were carried out both in a flow reactor with mass-quadrupole detection of the reaction products and by using Fourier-transform IR (FTIR) characterization of the nature of the sulfate species. Both in-situ in a flow IR cell and ex-situ FT-IR studies of the evolution of the sulfate species as a function of time on stream and after regeneration of the sorbent-catalyst were done. The results indicate that Cu catalyzes the oxidn. of SO2 to SO3 in the presence of gaseous O and that SO3, present probably as S-bonded chemisorbed SO3, further reacts with near-lying sites of the support without desorption in the gas phase through a mechanism of surface transfer to form a sulfate linked to Al or reacts with Cu species to form a sulfate linked to Cu. The relative rates of these 2 reactions of formation of sulfate species are strongly affected by the reaction temp., which enhances in particular the former reaction. The latter sulfate species, however, is more easily regenerated by redn. [on SciFinder(R)]
Combined DeSOx/DeNOx reactions on a copper on alumina sorbent-catalyst. 1. Mechanism of sulfur dioxide oxidation-adsorption
CENTI, Gabriele;PERATHONER, Siglinda;
1992-01-01
Abstract
The mechanism of SO2 oxidn.-adsorption to form regenerable sulfates on a Cu-Al2O3 sorbent-catalyst was detd. The studies were carried out both in a flow reactor with mass-quadrupole detection of the reaction products and by using Fourier-transform IR (FTIR) characterization of the nature of the sulfate species. Both in-situ in a flow IR cell and ex-situ FT-IR studies of the evolution of the sulfate species as a function of time on stream and after regeneration of the sorbent-catalyst were done. The results indicate that Cu catalyzes the oxidn. of SO2 to SO3 in the presence of gaseous O and that SO3, present probably as S-bonded chemisorbed SO3, further reacts with near-lying sites of the support without desorption in the gas phase through a mechanism of surface transfer to form a sulfate linked to Al or reacts with Cu species to form a sulfate linked to Cu. The relative rates of these 2 reactions of formation of sulfate species are strongly affected by the reaction temp., which enhances in particular the former reaction. The latter sulfate species, however, is more easily regenerated by redn. [on SciFinder(R)]Pubblicazioni consigliate
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