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<p class="MsoNormal" style="line-height:16.5pt"><span style="font-family:"Times New Roman",serif"><img width="600" height="171" style="width:6.25in;height:1.7812in" id="Picture_x0020_2" src="cid:image001.jpg@01D9A820.47603ED0" alt="Dissertation Defense Announcement at the Cullen College of Engineering"></span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<b><span style="font-size:16.0pt;font-family:"Times New Roman",serif;color:red;text-transform:uppercase">ENHANCED METHANE CONVERSION OVER FOUR-WAY CATALYST FOR STOICHIOMETRIC NATURAL GAS VEHICLES EMISSION CONTROL </span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<span style="font-family:"Times New Roman",serif;text-transform:uppercase"> </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<b><span style="font-size:13.5pt;font-family:"Times New Roman",serif">Pak Wing Chen</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<span style="font-size:11.0pt;font-family:"Times New Roman",serif">June 26, 2023; 3:00 PM</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<span style="font-size:11.0pt;font-family:"Times New Roman",serif"><br>
<b>Room: </b><span style="color:black">Chemical Engineering Conference Room- S234</span></span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:16.5pt"><b><span style="font-size:11.0pt;font-family:"Times New Roman",serif"> Teams: </span></b><span style="font-size:11.0pt;font-family:"Times New Roman",serif">Meeting ID: 281 567 354
398 Passcode: BbJ4fx </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<b><span style="font-size:11.0pt;font-family:"Times New Roman",serif">Committee Chairs:</span></b><span style="font-size:11.0pt;font-family:"Times New Roman",serif"><br>
Michael P. Harold, PhD and Lars Grabow, PhD</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<b><span style="font-size:11.0pt;font-family:"Times New Roman",serif">Committee Members:</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<span style="font-size:10.0pt;font-family:"Times New Roman",serif">Jeffrey Rimer, Ph.D. <b>| </b>Stanko Brankovic, Ph.D. <b>|</b> Ru-Fen Liu, Ph.D. </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal" style="line-height:16.5pt"><b><span style="font-family:"Times New Roman",serif;color:#C8102E">Abstract</span></b><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify;line-height:16.5pt"><span style="font-size:11.0pt;font-family:"Times New Roman",serif;color:black"> Effective emission control technology is needed for purification of the exhaust gas from stoichiometric
natural gas vehicles (NGVs), to meet the increasingly stringent tailpipe emissions regulations on vehicles powered by internal combustion engines. This requires the development of a four-way catalyst (FWC) that can convert methane, non-methane hydrocarbons,
CO and NOx simultaneously. The current project focuses on methane conversion over the platinum group metal (PGM) based catalyst with spinel oxide as oxygen storage material (OSM). The added catalyst functionality from the OSM component requires detailed investigations
of the catalyst performance.</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify;line-height:16.5pt"><span style="font-size:11.0pt;font-family:"Times New Roman",serif;color:black"> The catalyst performances are evaluated from both experimental and modeling perspectives. In the experimental
parts of the work, the catalysts were tested using lab scale flow experiments under conditions close to the exhaust gas of stoichiometric NGVs. The combination of lean/rich feed modulation and the addition of spinel allows for enhanced CH<sub>4</sub> conversion.
Systematic and parametric studies that evaluate the catalyst activity over varying feed operation mode (time-invariant or modulated), feed compositions (air-fuel ratio) and feed temperatures were carried out. The impacts of catalyst formulation and structure
on the CH<sub>4</sub> conversion performance were also analyzed. The dynamic oxygen storage capacity of spinel was found to play a significant part for the CH<sub>4</sub> conversion enhancement under lean/rich feed modulation and the reaction mechanism of
the PGM+Spinel catalyst is proposed. </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify;line-height:16.5pt"><span style="font-size:11.0pt;font-family:"Times New Roman",serif;color:black"> In the modeling aspects of the work, global kinetic models over PGM were developed for the reactions
that have been identified to be the main reactions affecting the CH<sub>4</sub>conversion and product formations, namely water gas shift (WGS), steam reforming of CH<sub>4</sub>(SRM), total CH<sub>4</sub> oxidation and partial CH<sub>4</sub> oxidation. The
developed kinetic models over PGM are combined with the previously developed kinetic models of catalytic oxidation and dynamic oxygen storage capacity over spinel, and the integrated kinetic models are incorporated into the monolith reactor model. The model
simulation results are validated by the experimental data and the model is applied to further the understanding of the catalyst functionalities and to optimize the catalyst performance and formulations.</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Times New Roman",serif"><img width="600" height="82" style="width:6.25in;height:.8541in" id="Picture_x0020_1" src="cid:image002.jpg@01D9A820.47603ED0" alt="Engineered For What's Next"></span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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