Auto-cyclic reactor: Design and evaluation for the removal of unburned methane from emissions of natural gas engines

Zanoletti, Massimiliano; Klvana, D.; Kirchnerová, J.; Perrier, Michel; Guy, Christophe

doi:10.1016/j.ces.2008.10.007

Cited by 13 publications

(19 citation statements)

References 11 publications

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“…Since the methane combustion in the presence of excess water vapor and carbon dioxide is considerably inhibited and therefore slower, especially at lower temperatures, 14 comparing the two systems allows illustrating the effect of different kinetics on the ACR behavior. Furthermore, the data for methane combustion in air might be relevant for some other potential applications, for example for methane removal from fugitive methane gases.…”

Section: Resultsmentioning

confidence: 99%

“…Similar behavior was observed experimentally in the ACR pilot unit for comparable inlet conditions of temperature and methane concentration. 14 Figure 7 illustrates well the effect of steady state combustion of 1000 ppm methane in air on the temperature profile in the reactor and its response to decreasing the inlet temperature from 350 to 240°C during combustion, in this case leading to extinction. As the methane mixture is introduced, the hottest (reaction) zone moves along the reactor axis, increasing at the same time the temperature at the outlet.…”

Section: 2a Methane In Airmentioning

confidence: 98%

“…Values of all necessary physical can be found in the previous article, 14 but the kinetic parameters determined experimentally, 14 are for convenience to the reader reproduced in Table 2.…”

Section: Description Of the 2-d Mathematical Modelmentioning

confidence: 99%

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Modeling of Autocyclic Reactor for the Removal of Unburned Methane from Emissions of Natural Gas Engines

Zanoletti¹,

Klvana²,

Kirchnerová³

et al. 2010

Ind. Eng. Chem. Res.

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Natural gas represents an environmentally attractive alternative to diesel and gasoline fuels to reduce all automotive emissions. However, a relatively high content of unburned methane in the exhaust gases outweighs these benefits. To treat such emissions, a counter-current type fixed bed autocyclic reactor (ACR) was designed and built for laboratory testing. The efficiency of the ACR, loaded with palladium based catalysts (pellets and monoliths) was evaluated experimentally under a wide range of conditions. As a first step in modeling the ACR performance, a HT1-D model was developed to suit the actual reactor configuration. This model reproduced adequately the axial temperature profiles and methane conversion, but tuning parameters had to be used to account for heat transfer. To permit investigation of radial heat transfer and thus better understanding of the ACR behavior, a two-dimensional model was developed, and successfully validated against experimental data. The new HT2-Dt model allowed a full range of the ACR performance simulations.

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Section: Resultsmentioning

confidence: 99%

Section: 2a Methane In Airmentioning

confidence: 98%

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Modeling of Autocyclic Reactor for the Removal of Unburned Methane from Emissions of Natural Gas Engines

Zanoletti¹,

Klvana²,

Kirchnerová³

et al. 2010

Ind. Eng. Chem. Res.

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“…The oxidation reaction of CH 4 is more difficult than that of the other hydrocarbons due to the higher stability of the methane molecule. In addition, at low to moderate exhaust gas temperature of NGVs (300-500°C) unburnt CH 4 is still existing in the combustion gases [5,6]. CH 4 is a greenhouse gas that has a 23 times higher globalwarming potential than CO 2 [7] and for that reason the catalyst stability during its whole lifetime is essential.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Phosphorus Exposure on a Natural-Gas-Oxidation Catalyst

et al. 2016

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Phosphorus is found to have a deactivating effect on the catalytic activity of the studied natural-gas-oxidation catalyst. Accelerated laboratory-scale phosphorus treatment was done to the PtPd/Al 2 O 3 natural gas oxidation catalyst. The effect of phosphorus after low (0.065 M) and high (0.13 M) phosphorus concentration treatments was studied by using an inductively coupled plasma optical emission spectroscopy, N 2 physisorption, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. In addition, the behavior of the catalyst was studied by a Gasmet FT-IR gas analyzer. Based on the received results it can be concluded that phosphorus was adsorbed on the surface by chemical bonds forming phosphates (PO 4 ). In addition, the partial transformation of PdO to Pd was observed. Due to the phosphorus adsorption both the CO and CH 4 oxidation activities were lower after the phosphorus treatments compared with the fresh catalyst.

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“…However, it is a questionable development since methane possesses a 25 times higher greenhouse gas potential [2], and low temperature exhaust gas streams from combustion engines contain up to 5000 ppm of unburned methane [3]. Hence, the reduction of methane emissions is addressed to novel catalysts, which are highly active at low temperature over time on stream.…”

Section: Introductionmentioning

confidence: 99%

Structural Changes of Highly Active Pd/MeOx (Me = Fe, Co, Ni) during Catalytic Methane Combustion

et al. 2018

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Fe 2 O 3 , Co 3 O 4 and NiO nanoparticles were prepared via a citrate method and further functionalized with Pd by impregnation. The pure oxides as well as Pd/Fe 2 O 3 , Pd/Co 3 O 4 , and Pd/NiO (1, 5 and 10 wt % Pd) were employed for catalytic methane combustion under methane lean (1 vol %)/oxygen rich (18 vol %, balanced with nitrogen) conditions. Already, the pure metal oxides showed a high catalytic activity leading to complete conversion temperature of T 100 ≤ 500 • C. H 2 -TPR (Temperature-programmed reduction) experiments revealed that Pd-functionalized metal oxides exhibited enhanced redox activity compared to the pure oxides leading to improved catalytic combustion activity at lower temperatures. At a loading of 1 wt % Pd, 1Pd/Co 3 O 4 (T 100 = 360 • C) outperforms 1Pd/Fe 2 O 3 (T 100 = 410 • C) as well as 1Pd/NiO (T 100 = 380 • C). At a loading of 10 wt % Pd, T 100 could only be slightly reduced in all cases. 1Pd/Co 3 O 4 and 1Pd/NiO show reasonable stability over 70 h on stream at T 100 . XPS (X-ray photoelectron spectroscopy) and STEM (Scanning transmission electron microscopy) investigations revealed strong interactions between Pd and NiO as well as Co 3 O 4 , respectively, leading to dynamic transformations and reoxidation of Pd due to solid state reactions, which leads to the high long-term stability.

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Auto-cyclic reactor: Design and evaluation for the removal of unburned methane from emissions of natural gas engines

Cited by 13 publications

References 11 publications

Modeling of Autocyclic Reactor for the Removal of Unburned Methane from Emissions of Natural Gas Engines

Modeling of Autocyclic Reactor for the Removal of Unburned Methane from Emissions of Natural Gas Engines

The Influence of Phosphorus Exposure on a Natural-Gas-Oxidation Catalyst

Structural Changes of Highly Active Pd/MeOx (Me = Fe, Co, Ni) during Catalytic Methane Combustion

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