Role of Urania and Alumina as Supports in The Steam Reforming of n-Butane at Pressure over Nickel-Containing Catalysts

Bhatta, K. S. M.; Dixon, Graham

doi:10.1021/i360031a024

Cited by 23 publications

(6 citation statements)

References 6 publications

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“…3,16,[18][19][20][21] In studies of the steam reforming of higher hydrocarbons, heptane is usually used as a model hydrocarbon. 3,20,21 As mentioned earlier, the product mixture is initially rich with methane.…”

Section: Reaction Scheme and Kineticsmentioning

confidence: 99%

“…Earlier results have shown that, under typical operating conditions, the steam reforming of higher hydrocarbons is irreversible and the methanation and water−gas shift reactions rapidly approach equilibrium. ,,− In studies of the steam reforming of higher hydrocarbons, heptane is usually used as a model hydrocarbon. ,, As mentioned earlier, the product mixture is initially rich with methane. Steam reforming of methane takes place, and the kinetics of this reaction is also considered in the overall system.…”

Section: Reaction Scheme and Kineticsmentioning

confidence: 99%

“…Steam reforming of natural gas, mainly methane, has been widely studied in different reactor configurations. ,− However, the feedstock for hydrogen production varies from place to place because of the availability of hydrocarbons. , Recent years have shown progress in steam reforming technology, resulting in cheaper plants and higher feedstock flexibility because of the better materials used for reforming reactors, better control of coking, and better reforming catalysts . Steam reforming of higher hydrocarbons is of great importance for hydrogen production not only as a novel fuel, but also in the traditional chemical and petrochemical industries. ,,− Usually, steam reforming of higher hydrocarbons can be represented by the following reactions 3 …”

Section: Introductionmentioning

confidence: 99%

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Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Chen

Yan

Elnashaie

2003

Ind. Eng. Chem. Res.

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The nonmonotonic behavior observed in hydrogen production from the steam reforming of higher hydrocarbons over nickel catalyst in an earlier-suggested novel circulating fast fluidized bed membrane reformer (CFFBMR) (Chen et al. AIChE J. 2003, 49 (5), 1250-1265) is extensively investigated. The investigation is carried out using kinetic model simulation at 623-823 K and 1013 kPa. Hydrogen-permselective membranes are used under cocurrent and countercurrent operations. The results show that the yield of hydrogen decreases at 623-723 K and then increases at 723-823 K. At 623 K, heptane is not fully converted, and thermodynamic equilibrium is not established. In contrast at 723-823 K, heptane is fully converted, and thermodynamic equilibrium is established. The strong methanation reaction at 723 K makes the hydrogen yield much lower, whereas at 823 K, the steam reforming of methane becomes increasingly important, enhancing the production of hydrogen. Using hydrogen-permselective membranes, the thermodynamic equilibrium limitation is "broken", and the CFFBMR performance is significantly improved. However, because of the small or negative driving force for hydrogen permeation under cocurrent operation, the hydrogen yield at 723 K is still lower. To improve this process, countercurrent operation is further investigated and found to be more efficient for hydrogen production when hydrogen-permselective membranes are used at 723-823 K. The purity of the exit hydrogen in the membranes is 90.65 and 92.83 mol % for cocurrent and countercurrent operations, respectively, at 823 K. If the sweep gas steam is further condensed, the purity of hydrogen could be as high as 99.45 and 99.59 mol %, respectively.

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Section: Reaction Scheme and Kineticsmentioning

confidence: 99%

Section: Reaction Scheme and Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Chen

Yan

Elnashaie

2003

Ind. Eng. Chem. Res.

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“…It has been reported that during steam reforming reactions, the support is the principal site for water activation and that metal sites are responsible for hydrocarbon activation . In the cases of Rh/γ‐Al 2 O 3 and Rh/ZrO 2 , propane was adsorbed on active Rh surface sites, and steam was adsorbed on support surface sites.…”

Section: Resultsmentioning

confidence: 99%

Rh/Ce_0.25Zr_0.75O₂ Catalyst for Steam Reforming of Propane at Low Temperature

2019

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Solid oxide fuel cells (SOFCs) show high energy-conversion efficiency and thus emit less CO 2 than conventional combustion engines. Although SOFCs can directly convert hydrocarbons such as liquefied petroleum gas, these fuels readily induce coking on the electrodes of fuel cell stacks. To avoid coking, hydrocarbons can be subjected to a preliminary endothermic steam-reforming step at a relatively low temperature using waste heat from the stack. Herein, we report that a Rh/ Ce 0.25 Zr 0.75 O 2 catalyst exhibited higher propane-steam-reforming activity than other Rh/Ce 1À x Zr x O 2 catalysts and Rh/γ-Al 2 O 3 . Catalyst characterization revealed that Rh/Ce 0.25 Zr 0.75 O 2 had excellent redox property and high H 2 O-adsorption activity, which contributed to the activation of steam and thus enhanced the propane-steam-reforming activity of this catalyst. Results and DiscussionThe temperature dependences of the catalytic activities of Rh/ Ce 1À x Zr x O 2 and Rh/γ-Al 2 O 3 are shown in Figure 1a. At 200°C, no propane consumption was observed over Rh/γ-Al 2 O 3 , and conversion was low over all the Rh/Ce 1À x Zr x O 2 catalysts. At 250°C, some of the propane was consumed, and the propaneconversion activities of the catalysts decreased in the order Rh/ Ce 0.25 Zr 0.75 O 2 > Rh/Ce 0.5 Zr 0.5 O 2 > Rh/Ce 0.75 Zr 0.25 O 2 > Rh/CeO 2 > Rh/ ZrO 2 > Rh/γ-Al 2 O 3 . At the target temperature for this study (300°C), Rh/Ce 0.25 Zr 0.75 O 2 showed the best activity: the propane conversion reached 55 %, which was 6 times that over Rh/γ-Al 2 O 3 . At 300°C, the catalyst activities for propane conversion decreased in the order Rh/Ce 0.25 Zr 0.75 O 2 > Rh/Ce 0.5 Zr 0.5 O 2 > Rh/ ZrO 2 > Rh/Ce 0.75 Zr 0.25 O 2 > Rh/CeO 2 (Figure 1b). At 350°C, propane conversion over Rh/Ce 0.25 Zr 0.75 O 2 and Rh/ZrO 2 reached 100 %, and the activities of the other catalysts decreased in the [a] L.

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“…CHx. Adsorption of steam is thOught to occur on the support on the basis of the observed influence of support type on the kinetics of the reaction (Bhatta and Dixon 1969). The adsorbed steam (or oxygen) reacts with the surface radical CHx to produce carbon monoxide and hydrogen.…”

Section: Catalytic Effectsmentioning

confidence: 99%

Catalysis in biomass gasification

Baker¹,

Mudge²

1984

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Carbon deposition Catalyst formu-Several types of carbon deposition on nickel catalysts are known to occur in steam-reforming of hydrocarbons. The mechanisms for formation of polymer, whisker, and pyrolytic carbons are discussed. These studies have revealed promising approaches to the development of effective catalyst systems for gasification of biomass. The influence of process variables, such as char residence time, gas velocity, and biomass particle size, has been shown to be important to the catalytic process design.

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Role of Urania and Alumina as Supports in The Steam Reforming of n-Butane at Pressure over Nickel-Containing Catalysts

Cited by 23 publications

References 6 publications

Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Rh/Ce_0.25Zr_0.75O₂ Catalyst for Steam Reforming of Propane at Low Temperature

Catalysis in biomass gasification

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Role of Urania and Alumina as Supports in The Steam Reforming of n-Butane at Pressure over Nickel-Containing Catalysts

Cited by 23 publications

References 6 publications

Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Nonmonotonic Behavior in Hydrogen Production from the Steam Reforming of Higher Hydrocarbons in a Circulating Fluidized Bed Membrane Reformer

Rh/Ce0.25Zr0.75O2 Catalyst for Steam Reforming of Propane at Low Temperature

Catalysis in biomass gasification

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Product

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About

Rh/Ce_0.25Zr_0.75O₂ Catalyst for Steam Reforming of Propane at Low Temperature