Search for dissertations about: "silver loading"

Showing result 1 - 5 of 7 swedish dissertations containing the words silver loading.

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. 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

5. 3. Lean NOx reduction over silver-alumina catalysts - Aspects on synthesis, structure and activity

   Author : Hannes Kannisto; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; freeze-drying; HC-SCR; DRIFTS.; aromatic hydrocarbons; silver-alumina; Lean NOx reduction; selective catalytic reduction; sol-gel; characterization; catalyst preparation; kinetic modeling;

   Abstract : The aim of this thesis is to increase the understanding of how to design highly active silver-alumina catalysts for selective catalytic reduction of NOx with hydrocarbons (HC-SCR) in oxygen excess at low temperatures (150-250 °C). Silver-alumina catalysts have been prepared using different methods, including a new unique preparation method developed during the thesis project. READ MORE

6. 4. 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

7. 5. Effect of water contamination on the diffused content of hydrogen under stress in AISI-52100 bearing steel

   Author : Tajammal Imran; Maskinelement; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vacuum technology; hydraulics; Mechanical engineering; materialteknik; Materiallära; Material technology; Hydrogen Diffusion; Rolling Element; Machine Elements; Tribology; Hydrogen Embrittlement; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Abstract : Abstract Hydrogen embrittlement is a degradation process of mechanical/tribological properties (toughness, wear etc.) of mating steel surfaces. This is caused by the presence and interaction of hydrogen with applied stresses. Therefore, it is important to quantify the hydrogen content which could be dissolved under applied stresses in steel. READ MORE