Sökning: "NH3 formation"

Visar resultat 11 - 15 av 48 avhandlingar innehållade orden NH3 formation.

1. 11. Fundamental deactivation mechanisms of Fe-BEA as NH3-SCR catalyst - Experimental studies and kinetic modeling

   Författare :Soran Shwan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dealumination; Hydrothermal treatment; Catalyst deactivation; NH3-SCR; Kinetic ageing model; Catalyst ageing; Fe-BEA;

   Sammanfattning : Due to globalization and an increasing transport sector the interest for more fuel efficient combustion engines operating under lean conditions has increased. The products formed during the burning process in internal combustion engines are major contributants to global air pollution, where carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOX) are the major toxic components regulated in many countries. LÄS MER

3. 12. Fundamentals of NH3-SCR and SOx chemistry over copper zeolite for the control of NOx and greenhouse gas (N2O) emissions

   Författare :Joonsoo Han; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; DeNOx; Cu SSZ-13; NH3-SCR; N2O; EATS; SO3; ammonium nitrate; SO2;

   Sammanfattning : The release of N2O over Cu-zeolite was investigated due to the critical contribution it makes to the atmosphere as one of the greenhouse gases (GHGs). An exhaust after-treatment system (EATS) for heavy-duty vehicles that uses Cu/SSZ-13 as the selective catalyst reduction (SCR) catalyst experiences not only a variety of flow, temperature and chemical conditions but is also exposed to various resulting contaminants. LÄS MER

4. 13. The effect of framework structure on N2O formation over Cu-based zeolites during NH3-SCR reactions

   Författare :Ghodsieh Isapour Toutizad; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CHA; MFI; Zeolites; SCR; Ammonium nitrate; Nitrous Oxide; BEA; Infrared spectroscopy; Catalysis;

   Sammanfattning : Anthropogenic nitrous oxide (N2O), which is generally formed as a byproduct of industrial chemical processes and fossil fuel combustion, has attracted significant attention in recent years due to its destructive role in global warming and ozone layer depletion. Among different developed technologies applied for lean NOx reduction, the selective catalytic reduction (SCR) of NOx with ammonia (as a reducing agent) is presently the most used method. LÄS MER

5. 14. Reactions on nanostructured and microporous surfaces

   Författare :Anna Clemens; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Cu-CHA; XRD; solid-state ion-exchange; materials characterisation; electron microscopy; NH3-SCR; zeolites; catalysis; nanostructured graphite; Water ice; DRIFTS; XPS; NOx reduction; Cu-SSZ-13; temperature programmed desorption; ultra-high vacuum; intercalation; UV-Vis spectroscopy;

   Sammanfattning : Interactions between surfaces and molecules play a central role in various fields where catalysis is one example. In order to understand different surface processes, physicochemical characterisation of the surface materials and molecules is required. LÄS MER

7. 15. Deactivation of SCR catalysts - Impact of sulfur and the use of biofuels

   Författare :Johanna Englund; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Cu-SSZ-13; Cu-CHA; Catalyst deactivation; Activity test; DeNOx; Sulfur; NOx reduction; NH3-SCR; FAME; Emission control; HVO; Vanadia; Biofuel;

   Sammanfattning : In a near future, limits on CO2 emissions from vehicles will be introduced, which requires development of more fuel-efficient engines and most likely a transition towards the use of more biofuels. With the implementation of biofuels several issues could arise, one being the lack of fuel standards for these new type of fuels, leading to higher concentrations of catalyst poisons compared to conventional fossil fuels. LÄS MER