Hetero-/homogeneous combustion of fuel-lean CH4/O2/N2 mixtures over PdO at elevated pressures

Sui, Ran; Mantzaras, John; Es-sebbar, Et-touhami; Bombach, Rolf

doi:10.1016/j.proci.2018.05.112

Cited by 19 publications

(15 citation statements)

References 31 publications

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“…The PdO x /SiO 2 -Acac catalysts (in particular for PdO 0.82 /SiO 2 -Acac when x = 0.82) exhibit much higher activity for lean methane oxidation at low temperature than Pd/SiO 2 -Acac and PdO/SiO 2 -Acac. As a result, we believe that it is just a coincidence between the non-monotonic dependence of the catalytic activity on the Pd oxidation state observed in this work and the non-monotonic pressure dependence of the catalytic reaction rate reported by Sui, Floren and co-workers [34,35]. In their cases, it seems that PdO was always the dominant active species during the whole reaction courses, whereas in this work, PdO x /SiO 2 with different Pd oxidation states was used and the oxidation state of Pd may even change during the reaction course.…”

Section: More About the Active Pdo X Species In Lean Methane Oxidationsupporting

confidence: 83%

“…Notably, Sui and co-workers observed a non-monotonic pressure dependence of the catalytic reaction rate in the range of 0.1-1.2 MPa [34], a behavior contrast to other noble metals (Pt and Rh) where the methane reaction rates always increased with rising pressure. The reactions were conducted at 627 • C and the volume contents of methane and oxygen were 4.9-6.0% and 24.8-40.7%, respectively.…”

Section: More About the Active Pdo X Species In Lean Methane Oxidationmentioning

confidence: 97%

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Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

et al. 2021

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A series of Pd/SiO2 catalysts were prepared with different Pd precursors by a dry ball-milling method and used in the catalytic oxidation of lean methane at low temperature. The effect of Pd precursors on the catalytic performance was investigated and the state of the most active Pd species was probed. The results indicate that dry ball-milling is a simple but rather effective method to prepare the Pd/SiO2 catalysts for lean methane oxidation, and palladium acetylacetonate is an ideal precursor to obtain a highly active Pd/SiO2-Acac catalyst with well- and stably dispersed Pd species, owing to the tight contact between acetylacetonate and Si–OH on the SiO2 support. Besides the size and dispersion of Pd particles, the oxidation state of Pd species also plays a crucial role in determining the catalytic activity of Pd/SiO2 in lean methane oxidation at low temperature. A non-monotonic dependence of the catalytic activity on the Pd oxidation state is observed. The activity of various Pd species follows the order of PdOx >> Pd > PdO; the PdOx/SiO2-Acac catalysts (in particular for PdO0.82/SiO2-Acac when x = 0.82) exhibit much higher activity in lean methane oxidation at low temperature than Pd/SiO2-Acac and PdO/SiO2-Acac. The catalytic activity of PdOx/SiO2 may degrade during the methane oxidation due to the gradual transformation of PdOx to PdO in the oxygen-rich ambiance; however, such degradation is reversible and the activity of a degraded Pd/SiO2 catalyst can be recovered through a redox treatment to regain the PdOx species. This work helps to foster a better understanding of the relationship between the structure and performance of supported Pd catalysts by clarifying the state of active Pd species, which should be beneficial to the design of an active catalyst in lean methane oxidation at low temperature.

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Section: More About the Active Pdo X Species In Lean Methane Oxidationsupporting

confidence: 83%

Section: More About the Active Pdo X Species In Lean Methane Oxidationmentioning

confidence: 97%

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

et al. 2021

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“…Hence, we can expect some interference between homogeneous gas-phase reactions and heterogeneous catalytic reactions inside the converter as observed for many other systems such as by the Mantzaras group for catalytically supported combustion. 45 Consequently, we will next study the interaction of gas-phase and surface reactions inside the catalytic converters.…”

Section: F I G U R E 1 3 Nh 3 /Nomentioning

confidence: 99%

Homogeneous conversion of NO_x and NH₃ with CH₄, CO, and C₂H₄ at the diluted conditions of exhaust‐gases of lean operated natural gas engines

Schmitt

Schwarz

Ruwe

et al. 2020

Int J of Chemical Kinetics

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Understanding gas-phase reactions in model gas mixtures approximating preturbine heavy-duty natural gas engine exhaust compositions containing NO, NH 3 , NO 2 , CH 4 , CO, and C 2 H 4 is extremely relevant for aftertreatment procedure and catalyst design and is thus addressed in this work. In a plug-flow reactor at atmospheric pressure, five different model gas mixtures were investigated in the temperature range of 700-1 200 K, using species analysis with electron ionization molecular-beam mass spectrometry. The mixtures were designed to reveal influences of individual components by adding NO 2 , CH 4 , CO, and C 2 H 4 sequentially to a highly argon-diluted NO/NH 3 base mixture. Effects of all components on the reactivity for NO x conversion were investigated both experimentally as well as by comparison with three selected kinetic models. Main results show a significantly increased reactivity upon NO 2 and hydrocarbon addition with lowered NO conversion temperatures by up to 200 K. Methane was seen to be of dominant influence in the carbon-containing mixtures regarding interactions between the carbon and nitrogen chemistry as well as formaldehyde formation. The three tested mechanisms were capable to overall represent the reaction behavior satisfactorily. On this basis, it can be stated that significant gas-phase reactivity was observed among typical constituents of pre-turbine natural gas engine exhaust at moderate temperature. K E Y W O R D S ammonia, exhaust gas aftertreatment, gas-phase kinetics, natural gas engines, nitric oxide This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

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“…Combustion of syngas (mixtures of H 2 and CO) can greatly reduce CO 2 emissions in power generation systems (Sui et al 2018(Sui et al , 2019(Sui et al , 2020a. In the field of syngas purification, there are several industrialized methods that could separately remove H 2 S and CO 2 , such as Selexol, methyldiethanolamine (MDEA), rectisol and pressure swing adsorption (PSA) (Chaubey et al 2013;Dincer and Acar 2015;Wiheeb et al 2013;Yu et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Development of new technology for coal gasification purification and research on the formation mechanism of pollutants

Zheng

Shi

Wang

et al. 2021

Int J Coal Sci Technol

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Coal-fired power generation is the main source of CO2 emission in China. To solve the problems of declined efficiency and increased costs caused by CO2 capture in coal-fired power systems, an integrated gasification fuel cell (IGFC) power generation technology was developed. The interaction mechanisms among coal gasification and purification, fuel cell and other components were further studied for IGFCs. Towards the direction of coal gasification and purification, we studied gasification reaction characteristics of ultrafine coal particles, ash melting characteristics and their effects on coal gasification reactions, the formation mechanism of pollutants. We further develop an elevated temperature/pressure swing adsorption rig for simultaneous H2S and CO2 removals. The results show the validity of the Miura-Maki model to describe the gasification of Shenhua bituminous coal with a good fit between the predicted DTG curves and experimental data. The designed 8–6–1 cycle procedure can effectively remove CO2 and H2S simultaneously with removal rate over 99.9%. In addition, transition metal oxides used as mercury removal adsorbents in coal gasified syngas were shown with great potential. The techniques presented in this paper can improve the gasification efficiency and reduce the formation of pollutants in IGFCs.

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Hetero-/homogeneous combustion of fuel-lean CH4/O2/N2 mixtures over PdO at elevated pressures

Cited by 19 publications

References 31 publications

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

Homogeneous conversion of NO_x and NH₃ with CH₄, CO, and C₂H₄ at the diluted conditions of exhaust‐gases of lean operated natural gas engines

Development of new technology for coal gasification purification and research on the formation mechanism of pollutants

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Hetero-/homogeneous combustion of fuel-lean CH4/O2/N2 mixtures over PdO at elevated pressures

Cited by 19 publications

References 31 publications

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

Homogeneous conversion of NOx and NH3 with CH4, CO, and C2H4 at the diluted conditions of exhaust‐gases of lean operated natural gas engines

Development of new technology for coal gasification purification and research on the formation mechanism of pollutants

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Homogeneous conversion of NO_x and NH₃ with CH₄, CO, and C₂H₄ at the diluted conditions of exhaust‐gases of lean operated natural gas engines