Search for dissertations about: "lean NOx reduction"

Showing result 11 - 15 of 54 swedish dissertations containing the words lean NOx reduction.

2. 11. Aging effects on commercial lean NOx trap catalysts

   Author : Jesus De Abreu Goes; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aging; thermal degradation; sulfur poisoning; characterization; commercial lean NOx traps; NOx storage and reduction;

   Abstract : As a countermeasure to global warming, vehicles with low carbon emissions are being investigated by promoting lean-burn engines and high combustion efficiencies. However, one limitation to the increasing use of these engines is the need to develop corresponding catalytic systems for controlling the nitrogen oxide (NOx) emissions in their lean exhaust. READ MORE

4. 12. Catalysis for Lean NOx Reduction - Aspects of Catalyst Synthesis and Surface Acidity

   Author : Hanna Härelind Ingelsten; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lean NOx reduction; silica; alumina; FTIR; surface acidity; model catalysts; platinum; HZSM-5; w o microemulsion; aluminum-silicate; hydrocarbon;

   Abstract : From both economic and environmental perspectives it is desirable to reduce the consumption of fossil fuels. One route to increase the fuel efficiency for vehicles is operation in oxygen excess. However, a major problem with this technique is the lean environment, which obstructs catalytic reduction of nitrogen oxides (NOx) to harmless nitrogen. READ MORE

5. 13. Kinetic Studies of NOx Storage and Reduction Catalysts - Flow Reactor Experiments and Microkinetic Modeling

   Author : Anna Maria Lindholm; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NOx reduction; flow reactor experiments; NOx storage; Pt Ba Al; NSR catalyst; microkinetic modeling; combined NSR and SCR system;

   Abstract : The NOx storage and reduction (NSR) technology is a promising technique to reduce NOx during oxygen excess e.g. in lean burn engine exhaust. A typical NSR catalyst consists of the following components: precious metals, such as platinum, palladium or rhodium, a storage component, usually barium, and a high surface area support, such as γ-alumina. READ MORE

6. 14. Hydrothermally induced changes of lean NOx reduction over Cu-ZSM-5 and stability improvements by synthesis modification

   Author : Malin Berggrund; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; hydrothermal stability; Cu-ZSM-5; propene; lean NOx reduction; HC-SCR; in-situ DRIFT;

   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 oxygen rich exhaust gases, where a conventional three-way catalyst cannot be used. READ MORE

7. 15. 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