Search for dissertations about: "silver alumina"

Showing result 1 - 5 of 17 swedish dissertations containing the words silver alumina.

  2. 1. 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

  4. 2. Silver Alumina Catalysts for Lean NOx Reduction - Influence of Preparation Methods and Type of Reductant, with Transient Kinetic Modelling

    Author : Hannes Kannisto; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; silver; kinetic modelling; Lean NOx reduction; sol-gel; preparation method; dispersion; cluster; HC-SCR; freeze-dry; XPS; alumina;

    Abstract : The objective of this work was to compare three different preparation methods for silver alumina catalysts for lean NOx reduction. Characteristics such as catalytic activity with propene and n-octane as reductants, chemical state of the silver and silver dispersion were analyzed. READ MORE

  5. 3. 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

  6. 4. Lean NOx reduction with methanol over supported silver catalysts

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

    Abstract : The oxygen rich and relatively cold exhaust gases from fuel-efficient combustion engines bring challenges for the reductive aftertreatment of NOx. In this context selective catalytic reduction over silver/alumina has shown positive results, especially with oxygenated reducing agents. READ MORE

  7. 5. Kinetic Studies of NO Oxidation and Reduction over Silver-Alumina Catalyst

    Author : Muhammad Mufti Azis; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TPD; Silver Alumina; HC-SCR; Kinetic modeling; Hydrogen effect; NOx reduction; NO oxidation.;

    Abstract : In line with growing concerns to manufacture more environmentally friendly vehicles, the use of internal combustion engines operating with oxygen excess or so called lean-burn engines will continue to be increasingly used. For lean-burn operation, reduction of NOx (NO+NO2) emissions is a major challenge and it is therefore urgently required to develop efficient and reliable NOx reduction aftertreatment systems for a wide variety of lean-burn or diesel engines. READ MORE