ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-11072016-163211


Tipo di tesi
Tesi di laurea magistrale
Autore
VALCHERA, SIMONE
URN
etd-11072016-163211
Titolo
Total Methane Oxidation on Supported Noble Metal Catalysts for Exhaust Gas Aftertreatment Systems
Dipartimento
INGEGNERIA CIVILE E INDUSTRIALE
Corso di studi
INGEGNERIA CHIMICA
Relatori
relatore Prof. Tognotti, Leonardo
Parole chiave
  • platinum
  • palladium
  • nitrogen physisorption
  • monolithic reactor
  • modeling
  • mercury porosimetry
  • kinetic model
  • incipient wetness impregnation
  • heterogeneous catalysis
  • diffusion limitations
  • CO chemisorption
  • catalyst synthesis
  • catalyst characterization
  • ball-milling
  • alumina
  • simulation
  • testing
  • washcoat
  • washcoat thickness
  • water inhibition
  • XRD
Data inizio appello
23/11/2016
Consultabilità
Non consultabile
Data di rilascio
23/11/2086
Riassunto
Aim of the study is to analyze the total methane oxidation on supported metal catalysts in monolithic reactors for exhaust gas aftertreatment systems.
Three different catalytic systems are compared: two monometallic, Pd/alumina and Pt/alumina, and one bimetallic, Pd-Pt/alumina.
The work ranges from synthesis to characterization of the catalysts, from testing under various conditions to modeling and simulation.
The catalysts powders are prepared by incipient wetness impregnation (IWI), which are subsequently ball-milled in order to obtain the slurry needed for the washcoating of the monoliths.
The physical and chemical properties of the systems are investigated through several characterization techniques, namely XRD analysis, CO chemisorption, nitrogen physisorption, mercury porosimetry and light microscope.
The performances of the monolithic structures are tested under different conditions, with dedicated focus on the effect of operating pressure and water content in the exhaust gas on the reaction conversion. Moreover, further tests are performed aiming at investigating the presence of diffusion limitations in the monolithic systems that could affect the overall reaction rate.
Furthermore, these systems are modeled by chosing both diffusion models for characterizing the transport phenomena and reaction rate expressions for determining the kinetic on the noble metal species. Global and microkinetic models are employeed.
Finally, the effect of pressure on the catalytic performance is simulated by means of the software DETCHEM. This step allows the validation of the assumed models.
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