- Email: [email protected]
Cleaner air is target of EPA
N17
yours the easy diffusion of reactants, products and of potential inhibitors such as water. A comparison (at 400°C) of the catalyst so developed, with the Cu-ZSM5 catalyst, currently among the most extensively studied, shows that the former keeps the initial very high activity virtually unaltered for over 4000 hours-on stream, while the latter decays within less than 500 hours. Activity measurements and lifetime runs have been made not only with simulated, but also with real exhausts. No significant differences were noticed in catalyst behaviour in these experiments, so confirming the superior quality of this catalyst with respect to any of the known deNOx systems. L. Forni
Low temperature VOC abatement catalyst Studies continue on alternative catalysts for precious metal (see Applied Catalysis B: Environmental Vol. 10/4 News Brief for related topics) for volatile organic compound (VOC) abatement from industrial processes. Studies reported by a group of scientists in England have found a low cost uranium-oxide based catalyst for destroying VOC's in the gas phase at low temperatures and high conversions comparable to or better than the present commercial precious metal catalyst. The U308 based catalyst has been shown to be effective for abatement of a number of compounds such as benzene, toluene, chlorobutane and chloro-benzene. No harmful byproducts (e.g. dioxin) were found in the studies for the abatement of chloro-organic compounds. Source: Chemical and Engineering News, December 2, 1996, page 19.
applied catalysis B: environmental
Cleaner air is target of EPA In November, the U.S. EPA proposed air emission standards that require more stringent ozone and particulate emission regulations. The national ambient air quality for ozone would be reduced from 120 ppb to 80 ppb and the size of the particulate matter would be reduced from 10/~m to 2.5 ~m. (See EM, 'Environmental Managers', October 1996, pp. 26-31 for an excellent review on the status of studies on 'The Scientific Basis for a Particulate Matter Standard'). Ozone is produced from the photochemical reaction of NOx and hydrocarbons that have been emitted to the atmosphere. EPA officials claim the newly proposed regulations are needed to protect the public health. These proposed regulations are meeting with opposition and there will be future debate regarding these proposed standards. Source: Chemical and Engineering News, December 2, 1996, page 14.
Impact of oxygenated fuels re-evaluated Field experience with oxygenated fuels added to gasoline to reduce emissions are not showing the impact initiated predicted. After a review of an EPA report by the National Research Council (NRC), the scientists found less reduction in carbon monoxide levels than predicted for use of oxygenated fuels. EPA had calculated that the use of oxygenated fuels may reduce CO by 30% while the NRC believes the reduction to be closer to 10% or lower. Source: EM, 'Environmental Manager', October 1996, page 8.
Volume 11 No. 2 -
7 February 1997
yours the easy diffusion of reactants, products and of potential inhibitors such as water. A comparison (at 400°C) of the catalyst so developed, with the Cu-ZSM5 catalyst, currently among the most extensively studied, shows that the former keeps the initial very high activity virtually unaltered for over 4000 hours-on stream, while the latter decays within less than 500 hours. Activity measurements and lifetime runs have been made not only with simulated, but also with real exhausts. No significant differences were noticed in catalyst behaviour in these experiments, so confirming the superior quality of this catalyst with respect to any of the known deNOx systems. L. Forni
Low temperature VOC abatement catalyst Studies continue on alternative catalysts for precious metal (see Applied Catalysis B: Environmental Vol. 10/4 News Brief for related topics) for volatile organic compound (VOC) abatement from industrial processes. Studies reported by a group of scientists in England have found a low cost uranium-oxide based catalyst for destroying VOC's in the gas phase at low temperatures and high conversions comparable to or better than the present commercial precious metal catalyst. The U308 based catalyst has been shown to be effective for abatement of a number of compounds such as benzene, toluene, chlorobutane and chloro-benzene. No harmful byproducts (e.g. dioxin) were found in the studies for the abatement of chloro-organic compounds. Source: Chemical and Engineering News, December 2, 1996, page 19.
applied catalysis B: environmental
Cleaner air is target of EPA In November, the U.S. EPA proposed air emission standards that require more stringent ozone and particulate emission regulations. The national ambient air quality for ozone would be reduced from 120 ppb to 80 ppb and the size of the particulate matter would be reduced from 10/~m to 2.5 ~m. (See EM, 'Environmental Managers', October 1996, pp. 26-31 for an excellent review on the status of studies on 'The Scientific Basis for a Particulate Matter Standard'). Ozone is produced from the photochemical reaction of NOx and hydrocarbons that have been emitted to the atmosphere. EPA officials claim the newly proposed regulations are needed to protect the public health. These proposed regulations are meeting with opposition and there will be future debate regarding these proposed standards. Source: Chemical and Engineering News, December 2, 1996, page 14.
Impact of oxygenated fuels re-evaluated Field experience with oxygenated fuels added to gasoline to reduce emissions are not showing the impact initiated predicted. After a review of an EPA report by the National Research Council (NRC), the scientists found less reduction in carbon monoxide levels than predicted for use of oxygenated fuels. EPA had calculated that the use of oxygenated fuels may reduce CO by 30% while the NRC believes the reduction to be closer to 10% or lower. Source: EM, 'Environmental Manager', October 1996, page 8.
Volume 11 No. 2 -
7 February 1997