Experimental and modeling-based analysis of reaction pathways on catalysts for natural gas engines under periodic lean/rich oscillations

Wang, Moyu; Eggenschwiler, Panayotis Dimopoulos; Ferri, Davide; Kröcher, Oliver

doi:10.1016/j.cej.2021.132848

Cited by 3 publications

(7 citation statements)

References 46 publications

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“…The potential of the Pt/Pd/Rh catalyst, which as demonstrated integrates the strength of both Pt and Pd, can [17,27,29,30]. This was attributed to high SR reaction rate [29], which is enabled by the periodic catalyst regeneration from carbonaceous species. The potential of the Pt/Pd/Rh catalyst, which as demonstrated integrates the strength of both Pt and Pd, can be best demonstrated using λ oscillations.…”

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

“…The Pt/Pd/Rh catalyst combines the advantage of the Pt/Rh catalyst at lean conditions and the benefit of the Pd/Rh catalyst under rich conditions. [17,27,29,30]. This was attributed to high SR reaction rate [29], which is enabled by the periodic catalyst regeneration from carbonaceous species.…”

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

“…[17,27,29,30]. This was attributed to high SR reaction rate [29], which is enabled by the periodic catalyst regeneration from carbonaceous species. The potential of the Pt/Pd/Rh catalyst, which as demonstrated integrates the strength of both Pt and Pd, can [17,27,29,30].…”

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

“…This was attributed to high SR reaction rate [29], which is enabled by the periodic catalyst regeneration from carbonaceous species. The potential of the Pt/Pd/Rh catalyst, which as demonstrated integrates the strength of both Pt and Pd, can [17,27,29,30]. This was attributed to high SR reaction rate [29], which is enabled by the periodic catalyst regeneration from carbonaceous species.…”

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

“…However, SR attenuates with time due to accumulated carbonaceous species on the ceria surface. Based on the temporary high SR reaction rate, λ oscillations across stoichiometry have been proposed to achieve lasting high CH 4 conversion [29]. λ conversion enhancement during λ oscillations was reported in several other works [17,27,30].…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

et al. 2022

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Methane abatement remains a challenge in aftertreatment systems of natural gas engines, currently under discussion in combination with synthetic methane. In this study, Pt/Rh and Pd/Rh-based three-way catalysts are investigated under various transient conditions because transients between O2 excess (lean) and O2-poor (rich) conditions can significantly enhance methane abatement. At mid to high temperatures, transitions from rich to lean feed yield higher rates of methane direct oxidation under lean conditions with the Pt/Rh catalyst, compared to the Pd/Rh catalyst. Both catalysts are able to trigger methane steam reforming (SR) after transitions from lean to rich feed. The SR reaction leads to increased H2 and NH3 formation. However, SR deactivates much faster in the Pt/Rh catalyst. At low temperature, the Pt/Rh catalyst is more active for SR. Results from an additional Pd-only catalyst confirm that Rh is essential for NOx conversion and high N2 selectivity. The distinct characteristics of Pt, Pd and Rh demonstrate the benefits obtained from the combination of the three platinum group metals. The potential of the Pt/Pd/Rh catalyst is proved to be significant throughout the complete engine map. Under optimized lean/rich oscillatory conditions, the Pt/Pd/Rh catalyst yields more than 95% methane conversion under almost all conditions while maintaining efficient abatement of all other pollutants.

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Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

Section: Conversion Characteristics Of Pt/pd/rh Catalystmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

et al. 2022

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Heat and Mass Transfer in the Steam Methane Reforming Process

Pashchenko

2023

Proceeding of International Heat Transfer Conference 17

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Methane Conversion in Stoichiometric Natural Gas Engine Exhaust

Karamitros,

Ibraimova,

Konstantinidis

et al. 2024

SAE Technical Paper Series

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<div class="section abstract"><div class="htmlview paragraph">Stoichiometric natural gas (CNG) engines are an attractive solution for heavy-duty vehicles considering their inherent advantage in emitting lower CO<sub>2</sub> emissions compared to their Diesel counterparts. Additionally, their aftertreatment system can be simpler and less costly as NOx reduction is handled simultaneously with CO/HC oxidation by a Three-Way Catalyst (TWC). The conversion of methane over a TWC shows a complex behavior, significantly different than non-methane hydrocarbons in stoichiometric gasoline engines. Its performance is maximized in a narrow A/F window and is strongly affected by the lean/rich cycling frequency. Experimental and simulation results indicate that lean-mode efficiency is governed by the palladium’s oxidation state while rich conversion is governed by the gradual formation of carbonaceous compounds which temporarily deactivate the active materials. Lean/rich cycling around stoichiometry enables a higher CH<sub>4</sub> oxidation as the oxygen storage seems to balance the individual effects of Pd oxidation and rich deactivation. In this work, the catalytic reaction mechanisms involved in CH<sub>4</sub>, CO and NOx conversion were studied by means of a multi-scale experimental campaign and mathematical modeling. Initially, a detailed kinetic study was performed on the synthetic-gas bench to understand the underlying phenomena and formulate the appropriate reaction mechanisms. The model was then evaluated under transient reactor experiments while final validation was performed against driving cycle measurements on the engine bench.</div></div>

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Experimental and modeling-based analysis of reaction pathways on catalysts for natural gas engines under periodic lean/rich oscillations

Cited by 3 publications

References 46 publications

Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

Heat and Mass Transfer in the Steam Methane Reforming Process

Methane Conversion in Stoichiometric Natural Gas Engine Exhaust

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