Title: NO oxidation over hydrophobic H-ZSM-5 molecular sieves.
Abstract: Based on the principle that molecular sieve ZSM-5 can be highly hydrophobic by using a high Si/Al2 ratio, a silica rich H-ZSM-5 was used as the NO oxidation catalyst and its catalytic activity under various reaction conditions was investigated: relative humidity from 0 to 100%, reaction temperature from 10 to 90℃, and inlet NO concentration from 0.05% to 0.08%. H-ZSM-5 catalyzed NO oxidation efficiently in the presence of vapor. When the Si/Al2 ratio of H-ZSM-5 increased from 50 to 300, the steady-state NO oxidation conversion in wet NOx gas (H2O concentration was 1.18%) raised from 20% to 56%. The oxidation conversion in dry gas decreased monotonously as reaction temperature increased, and low temperature was favorable for NO oxidation. In wet gas (H2O concentration was 1.18%) the optimal reaction temperature for NO oxidation was 20 ℃, which was close to the temperature of NOx in exhaust gas. The NO conversion decreased when temperature was below or above. A 200h stability test was conducted at 30℃, with an inlet NO concentration of 0.08% and a space time of 0.5s. The NO oxidation conversion reached to 60% and 50%, when the relative humidity was 50% and 100%, respectively. ZSM-5 catalyst displayed high stability in saturated wet gas and it converted the waste gas into an optimum composition for alkali absorption of NOx.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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Cited By Count: 2
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