The Experts below are selected from a list of 18573 Experts worldwide ranked by ideXlab platform
William F Schneider - One of the best experts on this subject based on the ideXlab platform.
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analysis of the thermodynamic feasibility of nox decomposition catalysis to meet next generation vehicle nox Emissions Standards
Applied Catalysis B-environmental, 2002Co-Authors: Christian T Goralski, William F SchneiderAbstract:Abstract Free energy minimization calculations are used to determine the thermodynamic equilibrium concentrations of NOx and other species in stoichiometric and lean gas mixtures over a range of temperatures and compositions. Under lean (excess N2 and O2) conditions, the NO decomposition (NO↔(1/2)N2+(1/2)O2) and NO oxidation (NO+(1/2)O2↔NO2) equilibria impose lower bounds on the NOx concentrations achievable by thermodynamic equilibration or NOx decomposition, and these equilibrium NOx concentrations can be practically significant. Assuming a perfect isothermal catalyst acting on a representative diesel exhaust stream collected over the federal test procedure (FTP) cycle, equilibrium NOx levels exceed upcoming California Low Emission Vehicle II (LEV-II) and Tier II NOx Emissions Standards for automobiles and trucks at temperatures above approximately 800 K. Consideration of a perfect adiabatic catalyst acting on the same diesel exhaust shows that equilibrium NOx values can fall below NOx Emissions Standards at lower temperatures, but to achieve these low concentrations would require the catalyst to attain 100% approach to equilibrium at very low temperatures. It is concluded that NOx removal based on a thermodynamic equilibrating catalyst under lean exhaust conditions is not practically viable for automotive application, and that to achieve upcoming NOx Standards will require selective NOx catalysts that vigorously promote NOx reactions with reductant and do not promote NO decomposition or oxidation. Finally, the ability of a selective NOx catalyst system to reduce NOx concentrations to or below thermodynamic equilibrium values is proposed as a useful measure for selective catalytic reduction (SCR) activity.
Peter Paone - One of the best experts on this subject based on the ideXlab platform.
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Supplementary Cementitious Materials: Concepts for the Treatment of Raw Materials
IEEE Industry Applications Magazine, 2014Co-Authors: James Ballan, Peter PaoneAbstract:The cement industry is under increasing pressure to provide environmentally friendly and sustainable products while also meeting more stringent Emissions Standards. Globally, cement producers are trending toward the incorporation of supplementary cementitious materials (SCMs) to address these challenges, but traditional methods limit the ability to meet national Standards. This article presents concepts for the treatment of raw materials for the manufacture of supplementary cementitious materials. The systems produce a high-quality product, allowing increased use in cement blends. The flexibility of these concepts permits the use of a wide variety of raw materials to produce high-quality products with lower fuel consumption and lower Emissions compared to the traditional methods.
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Processes for activation and manufacturing of supplementary cementitious materials
2012 IEEE-IAS PCA 54th Cement Industry Technical Conference, 2012Co-Authors: James Ballan, Peter PaoneAbstract:The cement industry is under increasing pressure to provide environmentally friendly and sustainable products while also meeting more stringent Emissions Standards. Globally, cement producers are trending towards incorporation of supplementary cementitious materials to address these challenges, but traditional methods limit the ability to meet national Standards. This paper presents concepts for the treatment of raw materials for the manufacture of supplementary cementitious materials. The systems produce a high quality product which allows for increased use in cement blends. The flexibility of these concepts allows for the use of a wide variety of raw materials to produce high quality products with lower fuel consumption and lower Emissions over traditional methods.
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Mercury controls for the cement industry
2010 IEEE-IAS PCA 52nd Cement Industry Technical Conference, 2010Co-Authors: Peter PaoneAbstract:In May of 2009, the United States Environmental Protection Agency (EPA) proposed a number of new limits on Emissions of pollutants from the cement industry under the provisions of the Clean Air Act. Among the proposed limits, a new set of Emissions Standards for mercury has garnered a great deal of attention from environmentalists and industry advocates alike. While the limits have not been finalized, it has become clear that a number of plants will need some type of control for mercury Emissions. This paper explores several options for reducing mercury Emissions in the cement industry.
Christian T Goralski - One of the best experts on this subject based on the ideXlab platform.
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analysis of the thermodynamic feasibility of nox decomposition catalysis to meet next generation vehicle nox Emissions Standards
Applied Catalysis B-environmental, 2002Co-Authors: Christian T Goralski, William F SchneiderAbstract:Abstract Free energy minimization calculations are used to determine the thermodynamic equilibrium concentrations of NOx and other species in stoichiometric and lean gas mixtures over a range of temperatures and compositions. Under lean (excess N2 and O2) conditions, the NO decomposition (NO↔(1/2)N2+(1/2)O2) and NO oxidation (NO+(1/2)O2↔NO2) equilibria impose lower bounds on the NOx concentrations achievable by thermodynamic equilibration or NOx decomposition, and these equilibrium NOx concentrations can be practically significant. Assuming a perfect isothermal catalyst acting on a representative diesel exhaust stream collected over the federal test procedure (FTP) cycle, equilibrium NOx levels exceed upcoming California Low Emission Vehicle II (LEV-II) and Tier II NOx Emissions Standards for automobiles and trucks at temperatures above approximately 800 K. Consideration of a perfect adiabatic catalyst acting on the same diesel exhaust shows that equilibrium NOx values can fall below NOx Emissions Standards at lower temperatures, but to achieve these low concentrations would require the catalyst to attain 100% approach to equilibrium at very low temperatures. It is concluded that NOx removal based on a thermodynamic equilibrating catalyst under lean exhaust conditions is not practically viable for automotive application, and that to achieve upcoming NOx Standards will require selective NOx catalysts that vigorously promote NOx reactions with reductant and do not promote NO decomposition or oxidation. Finally, the ability of a selective NOx catalyst system to reduce NOx concentrations to or below thermodynamic equilibrium values is proposed as a useful measure for selective catalytic reduction (SCR) activity.
Niklas Schmidt - One of the best experts on this subject based on the ideXlab platform.
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Real-World NOX Emissions of Transit Buses Equipped with Diesel Exhaust Aftertreatment Systems
Emission Control Science and Technology, 2017Co-Authors: Andrew J. Kotz, William F. Northrop, David B. Kittelson, Niklas SchmidtAbstract:In this work, we compare nitrogen oxide (NOX) Emissions from vehicles equipped with 2013 and 2015 model year (MY) diesel engines and exhaust aftertreatment, both certified to the same Emissions Standards, over a variety of real-world drive cycles. Our study concludes that 2013MY and 2015MY buses achieved real-world NOX conversion efficiencies of 75 and 95%, respectively. Engine-out NOX levels remained unchanged between the two busses when driven over the same transit bus routes. Therefore, Emissions reductions are attributed to greater NOX conversion efficiency by the exhaust aftertreatment system, especially in low catalyst temperature and transient response scenarios. Although it is likely that other transit buses and vocational vehicles will express different characteristics based on their specific operating conditions and powertrain setup; our results show that improvements to aftertreatment systems, in the areas of catalyst activity, aftertreatment controls, and urea dosing strategy can significantly reduce NOX Emissions over the investigated real-world drive cycles.
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Real-World NO_ X Emissions of Transit Buses Equipped with Diesel Exhaust Aftertreatment Systems
Emission Control Science and Technology, 2017Co-Authors: Andrew J. Kotz, William F. Northrop, David B. Kittelson, Niklas SchmidtAbstract:In this work, we compare nitrogen oxide (NO_ X ) Emissions from vehicles equipped with 2013 and 2015 model year (MY) diesel engines and exhaust aftertreatment, both certified to the same Emissions Standards, over a variety of real-world drive cycles. Our study concludes that 2013MY and 2015MY buses achieved real-world NO_ X conversion efficiencies of 75 and 95%, respectively. Engine-out NO_ X levels remained unchanged between the two busses when driven over the same transit bus routes. Therefore, Emissions reductions are attributed to greater NO_ X conversion efficiency by the exhaust aftertreatment system, especially in low catalyst temperature and transient response scenarios. Although it is likely that other transit buses and vocational vehicles will express different characteristics based on their specific operating conditions and powertrain setup; our results show that improvements to aftertreatment systems, in the areas of catalyst activity, aftertreatment controls, and urea dosing strategy can significantly reduce NO_ X Emissions over the investigated real-world drive cycles.
M C Bell - One of the best experts on this subject based on the ideXlab platform.
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the significance of vehicle Emissions Standards for levels of exhaust pollution from light vehicles in an urban area
Atmospheric Environment, 2011Co-Authors: G A Rhystyler, W Legassick, M C BellAbstract:This paper addresses the research question “Are more stringent exhaust Emissions Standards, as applied to light vehicle type approval, resulting in reduced vehicle pollution in an urban area?” The exhaust Emissions of a sample of over fifty thousand road vehicles operating in London were measured using roadside remote sensing absorption spectroscopy techniques (infrared and ultraviolet), combined with Automatic Number Plate Recognition for vehicle identification. Levels of carbon monoxide (CO), hydrocarbons (HC), nitric oxide (NO), and smoke (particulate) exhaust Emissions are reported by vehicle class, fuel type, and Euro Emissions standard. Emissions from petrol cars of each pollutant were all observed to display a statistically significant reduction with the introduction of each successive Euro Emissions standard from Euro 1 onwards. However, Euro 2 diesel cars were observed to emit statistically higher rates of NO than either Euro 1 or Euro 3 standard diesel cars. The study also confirms the continuing ‘dieselisation’ of the UK passenger car fleet. Mean NO Emissions from Euro 4 diesel cars were found to be 6 times higher than Euro 4 petrol cars, highlighting the need to develop a sound understanding of the current and future ‘in-use’ Emissions characteristics of diesel vehicles, and their influence on local air quality. Smoke Emissions from TXII London taxis (black cabs) were found to be statistically higher than either earlier TX1 or later TX4 model variants, with possible implications for local air quality policy interventions such as maximum age limits for taxis.
