Search for dissertations about: "Lean exhausts"

Showing result 1 - 5 of 6 swedish dissertations containing the words Lean exhausts.

  1. 1. Exhaust aftertreatment under lean conditions, regenerable SOx traps and NOx reduction catalysts

    Author : Lisa Kylhammar; [2007]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Heterogenous catalysis; Selective catalytic reduction; HC-SCR; Sulfur storage; SOx trap; Spectroscopy; Lean exhausts; NOx; Ag Al2O3; DRIFT; XPS;

    Abstract : The aim of this thesis was to investigate i) potential materials for regenerable SOx traps and ii) the influence of silver distribution within Ag/Al2O3 catalysts on the selective reduction of NOx by hydrocarbons (HC-SCR). Both areas are highly relevant for present and future vehicle aftertreatment technologies for lean exhausts. READ MORE

  2. 2. NOx reduction with dimethyl ether in lean exhaust

    Author : Sara U Erkfeldt; [2009]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NOx storage; Dimethyl ether; ether; hydrocarbon-SCR; lean NOx reduction; alcohol; Cu-ZSM-5; lean NOx trap; alkane; alternative fuel;

    Abstract : There is a growing concern worldwide about the increase in anthropogenic greenhouse gas emissions, particularly carbon dioxide (CO2) from the combustion of fossil fuels. Vehicles with internal combustion engines contribute significantly to these emissions, which has led to an increased demand for engines running on alternative (non-fossil) fuels. READ MORE

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

    Author : Fredrik Gunnarsson; [2014]
    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. 4. Studies on Lean NOx Reduction with Ammonia. Catalysts and Sensors

    Author : Mikaela Wallin; [2005]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; catalysis; Pt SiO2; NOx reduction; gas sensor; DFT; SCR; H-ZSM-5; in situ FTIR; LCAO; DRIFT; high throughput screening; transient ammonia supply; ammonia; microemulsion; perovskite;

    Abstract : Selective catalytic reduction of NOx with ammonia, NH3-SCR, is a promising technique to reduce NOx under lean conditions, e.g. in diesel engine exhausts. The main objective of this thesis was to gain further understanding of key parameters affecting the performance of catalysts and sensors for NH3-SCR. READ MORE

  5. 5. NOx Storage and Reduction Catalysts. Reduction with Hydrogen and the Influence of Water and Carbon Dioxide

    Author : Anna Maria Lindholm; [2007]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NSR catalyst; Pt Ba Al; H2O; CO2; Pt Al; NOx reduction; H2; NH3 formation; NOx storage; Lean NOx Trap; N2O formation; kinetic modeling; Pt Si;

    Abstract : Environmental concern has increased over the past several years and resulted in stringent emission legislation on NOx, CO, and hydrocarbon emissions from automobile exhausts. Moreover, the demands to improve the fuel efficiency of engines and to lower the CO2 emissions have increased, and a way to meet this is by using lean burn engines which operate with oxygen excess. READ MORE