Abstract
The removal of nitrogen oxides from the exhaust of lean-burn gasoline fuelled and diesel-fuelled engines, operating under net oxidizing conditions, has recently attracted considerable attention. In this work, three different catalytic systems (Al{sub 2}O{sub 3}, Cu/Al{sub 2}O{sub 3} and Cu/ZSM-5) are investigated for their suitability as catalysts for the selective reduction of nitrogen oxides by hydrocarbons in excess oxygen. Special emphasis is given to the formation of potentially harmful byproducts such as hydrogen cyanide (HCN), cyanic acid (HNCO), ammonia (NH{sub 3}) and nitrous oxide (N{sub 2}O). The effect of reaction temperature, nitrogen oxide (NO, NO{sub 2}), hydrocarbon (ethene, propene) and water on activity and the formation of byproducts is investigated. In situ FTIR spectroscopy and temperature-programmed surface reactions (TPSR) of absorbed species in different atmospheres were used to investigate the nature and reactivity of adsorbates formed under reaction conditions. The catalytic activity was strongly influenced by the presence of water in the feed. The effects of the other parameters were suppressed and the performance generally decreased, except when propene was used for the reduction of NO{sub x} over Cu/ZSM-5. Over Cu/ZSM-5 clearly higher conversion was obtained, when ethene was used as reducing agent, while there was no significant difference when
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Citation Formats
Radtke, F.
Selective catalytic reduction of NO{sub x} by olefins.
Switzerland: N. p.,
1996.
Web.
Radtke, F.
Selective catalytic reduction of NO{sub x} by olefins.
Switzerland.
Radtke, F.
1996.
"Selective catalytic reduction of NO{sub x} by olefins."
Switzerland.
@misc{etde_495613,
title = {Selective catalytic reduction of NO{sub x} by olefins}
author = {Radtke, F}
abstractNote = {The removal of nitrogen oxides from the exhaust of lean-burn gasoline fuelled and diesel-fuelled engines, operating under net oxidizing conditions, has recently attracted considerable attention. In this work, three different catalytic systems (Al{sub 2}O{sub 3}, Cu/Al{sub 2}O{sub 3} and Cu/ZSM-5) are investigated for their suitability as catalysts for the selective reduction of nitrogen oxides by hydrocarbons in excess oxygen. Special emphasis is given to the formation of potentially harmful byproducts such as hydrogen cyanide (HCN), cyanic acid (HNCO), ammonia (NH{sub 3}) and nitrous oxide (N{sub 2}O). The effect of reaction temperature, nitrogen oxide (NO, NO{sub 2}), hydrocarbon (ethene, propene) and water on activity and the formation of byproducts is investigated. In situ FTIR spectroscopy and temperature-programmed surface reactions (TPSR) of absorbed species in different atmospheres were used to investigate the nature and reactivity of adsorbates formed under reaction conditions. The catalytic activity was strongly influenced by the presence of water in the feed. The effects of the other parameters were suppressed and the performance generally decreased, except when propene was used for the reduction of NO{sub x} over Cu/ZSM-5. Over Cu/ZSM-5 clearly higher conversion was obtained, when ethene was used as reducing agent, while there was no significant difference when starting from NO or NO{sub 2}. In contrast, with {gamma}-Al{sub 2}O{sub 3} NO{sub 2} was reduced more efficiently than NO with both reductants. The impregnation of {gamma}-Al{sub 2}O{sub 3} with copper led to an extensive loss of this performance. For dry feeds and with increasing CuO loading, the catalysts reached maximum activity at lower temperature and the maximum yield of nitrogen slightly decreased. (author) figs., tabs., refs.}
place = {Switzerland}
year = {1996}
month = {Dec}
}
title = {Selective catalytic reduction of NO{sub x} by olefins}
author = {Radtke, F}
abstractNote = {The removal of nitrogen oxides from the exhaust of lean-burn gasoline fuelled and diesel-fuelled engines, operating under net oxidizing conditions, has recently attracted considerable attention. In this work, three different catalytic systems (Al{sub 2}O{sub 3}, Cu/Al{sub 2}O{sub 3} and Cu/ZSM-5) are investigated for their suitability as catalysts for the selective reduction of nitrogen oxides by hydrocarbons in excess oxygen. Special emphasis is given to the formation of potentially harmful byproducts such as hydrogen cyanide (HCN), cyanic acid (HNCO), ammonia (NH{sub 3}) and nitrous oxide (N{sub 2}O). The effect of reaction temperature, nitrogen oxide (NO, NO{sub 2}), hydrocarbon (ethene, propene) and water on activity and the formation of byproducts is investigated. In situ FTIR spectroscopy and temperature-programmed surface reactions (TPSR) of absorbed species in different atmospheres were used to investigate the nature and reactivity of adsorbates formed under reaction conditions. The catalytic activity was strongly influenced by the presence of water in the feed. The effects of the other parameters were suppressed and the performance generally decreased, except when propene was used for the reduction of NO{sub x} over Cu/ZSM-5. Over Cu/ZSM-5 clearly higher conversion was obtained, when ethene was used as reducing agent, while there was no significant difference when starting from NO or NO{sub 2}. In contrast, with {gamma}-Al{sub 2}O{sub 3} NO{sub 2} was reduced more efficiently than NO with both reductants. The impregnation of {gamma}-Al{sub 2}O{sub 3} with copper led to an extensive loss of this performance. For dry feeds and with increasing CuO loading, the catalysts reached maximum activity at lower temperature and the maximum yield of nitrogen slightly decreased. (author) figs., tabs., refs.}
place = {Switzerland}
year = {1996}
month = {Dec}
}