The catalytic behavior of the Cu on Al2O3 sorbent-catalyst in NO redn. with NH3/O2 during the simultaneous oxidn.-adsorption of SO2 was studied in a series of consecutive cycles of reaction-regeneration and as a function of the surface coverage with sulfate species. The behavior of a CuO/SiO2 system with simultaneous DeSOx/DeNOx reaction is also reported. Tests of thermal desorption for the anal. of residual adsorbed species after reaction and thermogravimetric tests of NH3 adsorption were also done. The results indicate that (1) there is an initial competition between the adsorption of NH3 to form an NH4HSO4 species and the reaction of NH3 with NO; (2) NH3 adsorption continues up to a complete 1:1 reaction with the surface sulfate species; (3) these competition and adsorption phenomena give rise to the presence of an induction time in reaching the steady-state catalytic behavior, with a neg. influence on the efficiency in NO removal; (4) and the sulfate species induces a decrease in the activity of the Cu-based active phase, with a redn. in NO conversion, but esp. an increase in the formation of unwanted N2O. Furthermore, desorption tests showed that the presence of adsorbed NH3 induces a desorption of SO2 when the catalyst temp. is increased from ∼570 K to 720 K and adsorbed NH3 thermally desorbs at higher reaction temps. as such or as products of further transformation, specifically N2. [on SciFinder(R)]

Combined DeSOx/DeNOx reactions on a copper on alumina sorbent-catalyst. 3. DeNOx behavior as a function of the surface coverage with sulfate species

CENTI, Gabriele;PERATHONER, Siglinda;
1992-01-01

Abstract

The catalytic behavior of the Cu on Al2O3 sorbent-catalyst in NO redn. with NH3/O2 during the simultaneous oxidn.-adsorption of SO2 was studied in a series of consecutive cycles of reaction-regeneration and as a function of the surface coverage with sulfate species. The behavior of a CuO/SiO2 system with simultaneous DeSOx/DeNOx reaction is also reported. Tests of thermal desorption for the anal. of residual adsorbed species after reaction and thermogravimetric tests of NH3 adsorption were also done. The results indicate that (1) there is an initial competition between the adsorption of NH3 to form an NH4HSO4 species and the reaction of NH3 with NO; (2) NH3 adsorption continues up to a complete 1:1 reaction with the surface sulfate species; (3) these competition and adsorption phenomena give rise to the presence of an induction time in reaching the steady-state catalytic behavior, with a neg. influence on the efficiency in NO removal; (4) and the sulfate species induces a decrease in the activity of the Cu-based active phase, with a redn. in NO conversion, but esp. an increase in the formation of unwanted N2O. Furthermore, desorption tests showed that the presence of adsorbed NH3 induces a desorption of SO2 when the catalyst temp. is increased from ∼570 K to 720 K and adsorbed NH3 thermally desorbs at higher reaction temps. as such or as products of further transformation, specifically N2. [on SciFinder(R)]
1992
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1907306
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