Sökning: "chemical exposure"

Visar resultat 1 - 5 av 557 avhandlingar innehållade orden chemical exposure.

1. 1. Metal-exchanged zeolites for NH3-SCR applications - Activity and Deactivation studies

   Författare :Soran Shwan; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; modeling; NOX.; Hydrothermal; Chemical; Kinetic; Copper; Deactivation; Iron; Zeolite; Nitrogen oxides; NH3; Ammonia; Catalyst; NSR; Emissions; Poisoning; Ageing; NH3-SCR;

   Sammanfattning : Emissions of nitrogen oxides (NOX) formed during the burning process in internal combustion engines is a major contributor to global air pollutions. One effective way to reduce NOX in lean environments, i.e. oxygen excess is selective catalytic reduction with ammonia (NH3-SCR). LÄS MER

3. 2. Behavior of iron-based oxygen carriers at deep reduction states

   Författare :Victor Purnomo; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; oxygen carrier; fuel conversion; chemical looping; physical performance; deep reduction; reactivity; iron oxides;

   Sammanfattning : Oxygen carriers have an important role as bed materials in both common circulating fluidized bed combustion unit (also known as oxygen-carrier-aided combustion, OCAC) and in various chemical looping processes. Contrary to conventional bed materials, e.g., sand, oxygen carriers are capable of transferring both oxygen and heat. LÄS MER

4. 3. Complete methane oxidation over alumina and zeolite supported palladium for emission control

   Författare :Ida Friberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Pd zeolite; Pd Al2O3; sulfur poisoning; stoichiometric; hydrothermal aging; water deactivation; regeneration; methane oxidation; Ba;

   Sammanfattning : The use of methane-based fuels, such as natural gas and biogas, gives lower emissions of for instance carbon dioxide (CO2) and particulate matters compared to traditionally used liquid fossil fuels. However, the exhaust gases contain significant levels of unburnt methane (CH4) residuals, which are desirable to minimize since CH4 has a high global warming potential. LÄS MER

5. 4. 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

7. 5. Aging of Lean NOX Trap Catalysts and Hydrocarbon Trapping in Cold-Start Applications

   Författare :Rasmus Jonsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : It is well known that combustion processes worldwide give rise to emissions such as nitrogen oxides (NOX), carbon monoxide (CO), hydrocarbons (HC) and particulates. For vehicles, the method for handling these emissions has been through the development of the catalytic converter. LÄS MER