Synthesis gas formation by direct oxidation of methane over Pt monoliths*1

Hickman, Daniel A.; Schmidt, L.D.

doi:10.1016/0021-9517(92)90022-a

Cited by 513 publications

(147 citation statements)

References 14 publications

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“…However, there are differences between the investigated CPOX of jet fuel surrogates on Rh and CPOX of methane on Pd, as we see a local minimum in CO molar fraction in the former case and a local minimum in CO 2 in the latter case. In studies with Pt and Pt/Rh, hydrogen and CO are shown as primary products at short contact times, whereas an influence on mass transport limitation by the variation of the catalyst geometry has been reported [7,39]. Additionally, a direct formation towards syngas has been suggested in a TAP (temporal analysis of products) reactor, different to this study, albeit on platinum catalysts [40].…”

Section: Reaction Zones In Methane Cpoxcontrasting

confidence: 64%

Spatial Concentration Profiles for the Catalytic Partial Oxidation of Jet Fuel Surrogates in a Rh/Al2O3 Coated Monolith

et al. 2016

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Abstract:The catalytic partial oxidation (CPOX) of several hydrocarbon mixtures, containing n-dodecane (DD), 1,2,4-trimethylbenzene (TMB), and benzothiophene (BT) as a sulfur compound was studied over a Rh/Al 2 O 3 honeycomb catalyst. The in-situ sampling technique SpaciPro was used in this study to investigate the complex reaction system which consisted of total and partial oxidation, steam reforming, and the water gas shift reaction. The mixtures of 83 vol % DD, 17 vol % TMB with and without addition of the sulfur compound BT, as well as the pure hydrocarbons were studied at a molar C/O-ratio of 0.75. The spatially resolved concentration and temperature profiles inside a central channel of the catalyst revealed three reaction zones: an oxidation zone, an oxy-reforming zone, and a reforming zone. Hydrogen formation starts in the oxy-reforming zone, not directly at the catalyst inlet, contrary to methane CPOX on Rh. In the reforming zone, in which steam reforming is the predominant reaction, even small amounts of sulfur (10 mg S in 1 kg fuel) block active sites.

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Section: Reaction Zones In Methane Cpoxcontrasting

confidence: 64%

Spatial Concentration Profiles for the Catalytic Partial Oxidation of Jet Fuel Surrogates in a Rh/Al2O3 Coated Monolith

et al. 2016

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“…However, Dissanayake et al (14) report that a difference between the measured and the actual reaction temperature also provides an explanation for the observed difference in selectivities. Formation of CO and H 2 as primary reaction products in the partial oxidation of methane is reported by Hickman and Schmidt (15)(16)(17) applying adiabatically operated monoliths containing a platinum or rhodium catalyst at outlet temperatures around 1300 K and residence times between 10 −4 and 10 −2 s. Simulations carried out on the basis of a model consisting of 19 elementary reaction steps provided a theoretical basis for this observation (18).…”

Section: Introductionmentioning

confidence: 78%

The Reaction Mechanism of the Partial Oxidation of Methane to Synthesis Gas: A Transient Kinetic Study over Rhodium and a Comparison with Platinum

Mallens

Hoebink

Marin

1997

Journal of Catalysis

148

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. M. M. (1997). The reaction mechanism of the partial oxidation of methane to synthesis gas: a transient kinetic study over rhodium and a comparison with platinum. Journal of Catalysis, 167(1), 43-56. DOI: 10.100643-56. DOI: 10. /jcat.199743-56. DOI: 10. .1533 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The partial oxidation of methane to synthesis gas over rhodium sponge has been investigated by admitting pulses of pure methane and pure oxygen as well as mixtures of methane and oxygen to rhodium sponge at temperatures from 873 to 1023 K. Moreover, pulses of oxygen followed by methane and vice versa as well as pulses of mixtures of methane and labelled oxygen were applied to study the role of chemisorbed oxygen and incorporated oxygen in the reaction mechanism. The decomposition of methane on reduced rhodium results in the formation of carbon and hydrogen adatoms. During the interaction of pure dioxygen with rhodium the catalyst is almost completely oxidized to Rh 2 O 3 . In addition to rhodium oxide, oxygen is also present in the form of chemisorbed oxygen species. During the simultaneous interaction of methane and dioxygen at a stoichiometric feed ratio and a temperature of 973 K only 0.4 wt% Rh 2 O 3 is present. The chemisorbed oxygen species are completely desorbed after 2 s. A Mars-Van Krevelen mechanism is postulated: methane reduces the rhodium oxide, which is reoxidized by dioxygen. Synthesis gas is produced as primary product. Hydrogen is formed via the associative desorption of two hydrogen adatoms from reduced rhodium and the reaction between carbon adatoms and oxygen present as rhodium oxide results in the formation of carbon monoxide. The consecutive oxidation of CO and H 2 proceeds via both chemisorbed oxygen and oxygen present as rhodium oxide. Continuous flow experiments were performed to compare rhodium and platinum. When compared to platinum, rhodium shows a higher conversion to methane at a comparable temperature and also a higher selectivity to both CO and H 2 , the difference for CO being most pronounced. The observed differences in methane conversion and selectivities for the two catalysts are ascribed to the higher activation energy for methane decomposition on platinum compared to rhodium. An additional explanation for the difference in H 2 selectivit...

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“…(10) and (11). As in the case of dry reforming, plausible values were obtained by assuming no carbon deposition.…”

Section: Partial Oxidation Of Methanementioning

confidence: 99%

Gas Composition Analysis Using Yttria-stabilized Zirconia Oxygen Sensor during Dry Reforming and Partial Oxidation of Methane

Muroyama

Okuda

Matsui

et al. 2018

J. Jpn. Petrol. Inst.

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Synthesis gas formation by direct oxidation of methane over Pt monoliths*1

Cited by 513 publications

References 14 publications

Spatial Concentration Profiles for the Catalytic Partial Oxidation of Jet Fuel Surrogates in a Rh/Al2O3 Coated Monolith

Spatial Concentration Profiles for the Catalytic Partial Oxidation of Jet Fuel Surrogates in a Rh/Al2O3 Coated Monolith

The Reaction Mechanism of the Partial Oxidation of Methane to Synthesis Gas: A Transient Kinetic Study over Rhodium and a Comparison with Platinum

Gas Composition Analysis Using Yttria-stabilized Zirconia Oxygen Sensor during Dry Reforming and Partial Oxidation of Methane

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