Search for dissertations about: "lean NOx reduction"

Showing result 16 - 20 of 54 swedish dissertations containing the words lean NOx reduction.

  2. 16. Lean NOx reduction over silver-alumina from lab-scale to real conditions - Effects of reducing agent and catalyst composition

    Author : Fredrik Gunnarsson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; ethanol; Ag Al2O3; Pt-doping; Lean NOx reduction; HC-SCR; low-temperature activity; catalyst ageing; biofuels;

    Abstract : Lean NOx reduction over silver-alumina from lab-scale to real conditions Effects of reducing agent and catalyst compositionFREDRIK GUNNARSSONApplied surface chemistryDepartment of Chemical and Biological EngineeringChalmers University of TechnologyAbstractThe focus of this work is to increase the understanding of lean NOx reduction over silver-alumina catalysts using hydrocarbons as the reducing agent (HC-SCR), in particular by investigating the effect of silver loading, the role of platinum doping, and the effect of the type of reducing agent. In addition, the effects of aging and hydrothermal treatment on the catalytic activity and selectivity, and the influence of real engine exhausts were investigated, with special attention to the low-temperature activity. READ MORE

  4. 17. Studies of a Heavy-Duty Diesel Aftertreatment System Based on the NOX Storage and Reduction Technology

    Author : Klaus Papadakis; Avdelningen för kemiteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fuel penalty; injection parameters; DoE; design of experiments; exhaust; diesel engine; NO oxidation; simulation; modelling; oxidation catalyst; NOX trap; NOX storage and reduction; NSR; Kemiteknik och kemisk teknologi; Chemical technology and engineering; dosing strategy; system optimisation;

    Abstract : The legislative limits for NOX emissions in the exhaust gas from heavy-duty diesel engines will be decreased in the European Union from today 3.5 g/kWh (Euro IV) to 2.0 g/kWh in 2008 (Euro V). In the USA and Japan a similar trend can be seen. READ MORE

  5. 18. Lean NOx reduction over supported silver catalysts with methanol as reductant - Influence of silver loading, support material, hydrogen addition and C/N molar ratio

    Author : Marika Männikkö; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hydrogen; silver loading; C N molar ratio; HC-SCR; lean NOx reduction; methanol; silver; alumina; ZSM-5;

    Abstract : The aim of this thesis is to find catalysts which show high activity and selectivity forlean NOx reduction in the low-temperature regime relevant for diesel and lean-burnengines and to investigate methanol as reducing agent. The lean NOx reduction oversupported silver catalysts is studied, focusing on the influence of the support material,silver loading, addition of hydrogen and the C/N molar ratio. READ MORE

  6. 19. Active sites and influence of reaction conditions on the selective catalytic reduction of NOx over the silver-alumina catalyst

    Author : Linda Ström; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; microemulsion; nanoalloys; DRIFTS; HC-SCR; indium; palladium; silver; XRD; UV-vis; alumina; NH3-TPD.; Lean NOx reduction; TEM; NH3-SCR;

    Abstract : Hazardous nitrogen oxides (NOx) are challenging to remove from fuel-efficient excess-oxygen operating engines. A promising solution is selective catalytic reduction (SCR) of NOx, using hydrocarbons (HC-SCR) or ammonia (NH3-SCR) as reducing agent. READ MORE

  7. 20. Studies of the influence of ZSM-5 synthesis on activity and stability of Cu-ZSM-5 in leand NOx reduction

    Author : Malin Berggrund; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HC-SCR; Cu-ZSM-5; catalysis; propene; lean NOx reduction; hydrothermal stability;

    Abstract : The growing concern about the global warming coupled with the increasing emissions of the greenhouse gas carbon dioxide, combined with the climbing oil price, drives the interest to more fuel efficient lean combustion engines for automotive applications. Such engines require new technical solutions for reduction of NOx in the exhaust gases, which are in excess oxygen, where a conventional three-way catalyst cannot be used to reduce NOx. READ MORE