Catalytically stabilized combustion

Pfefferle, William C.; Pfefferle, Lisa D.

doi:10.1016/0360-1285(86)90012-2

Cited by 124 publications

(49 citation statements)

References 36 publications

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“…Moreover, the highest surface temperatures are attained at the channel entry, as shown in Pfefferle and Pfefferle (1985). Experiments in the combustor of Figure 1 under such conditions led to a gaseous flame anchored directly at the hot entrance.…”

Section: Burner Geometrymentioning

confidence: 88%

“…The knowledge of hydrogen CST is, therefore, an important step in the understanding of hydrogen-assisted CST. In hydrogen-assisted CST, care has to be exercised to avoid catalyst hot-spots and homogeneous ignition within the catalytic reactor: H2 is a strongly diffusionally imbalanced fuel with a Lewis number Le » 0.3, resulting in superadiabatic surface temperatures (see Pfefferle and Pfefferle (1985)), that could deactivate the catalyst and promote homogeneous ignition.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Combustion of Hydrogen-Air Mixtures Over Platinum: Validation of Hetero/Homogeneous Chemical Reaction Schemes

Appel

Mantzaras

Schaeren

et al. 2004

Inter J Ener Clean Env

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The applicability of various hetero/homogeneous chemical reaction schemes in the catalytically stabilized combustion (CST) of hydrogen/air mixtures over platinum was investigated experimentally and numerically in channelflow configurations. The present work stems from the internationally intensified effort to commercialize power generation systems with ultra-low NOx (< 3 ppm), CSTbased gas turbines. Crucial in the development of such systems is the understanding of the heterogeneous (catalytic) kinetics, the homogeneous (gas-phase) kinetics, and their respective coupling. Experiments were performed at atmospheric pressure and laminar flow conditions in an optically-accessible catalytic channel combustor: planar laser induced fluorescence (PLIF) of the OH radical was used to monitor the onset of homogeneous ignition and line-Raman measurements provided the boundary-layer profiles of the temperature and major species. Measured homogeneous ignition distances were compared against numerical predictions obtained with a two-dimensional elliptic fluid mechanical model. Six homogeneous (elementary, reduced and single-step schemes) and three heterogeneous schemes were tested in the model. The comparisons have revealed substantial differences between measured and predicted homogeneous ignition distances (ranging from 8% to 85%) and, moreover, these differences were attributed primarily to the homogeneous reaction pathway.

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Section: Burner Geometrymentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Catalytic Combustion of Hydrogen-Air Mixtures Over Platinum: Validation of Hetero/Homogeneous Chemical Reaction Schemes

Appel

Mantzaras

Schaeren

et al. 2004

Inter J Ener Clean Env

View full text Add to dashboard Cite

show abstract

“…The average temperature of 5 locations of equal radial distance was termed as exit surface temperature. The first Figure 1 Experimental system of catalytic combustion with heating system 1 blower; 2 adjustable valve; 3 mass flow meter; 4 U type heater of air; 5 adjustable valve of natural gas; 6 mass flow meter of natural gas; 7 catalytic monolith; 8 thermocouple; 9 adiabatic layer; 10 emissions collection; 11 spark plug; 12 single direction valve; 13 metal flow guide; 14 mesh; 15 static mixer Figure 2 Velocity distribution on a cross-section of the tube with elbow (cross-sectional average velocity 0.186m·s 1 ) survey perpendicular to the center line of the elbow; survey from the direction outboard elbow to inboard measuring point was at the distance of 10mm of monolith brim and it was averagely 20mm's interval for the four other points.…”

Section: Methodsmentioning

confidence: 99%

“…Complete combustion of methane in homogeneous flame usually requires high temperature and it produces high level of NO x , unburned hydrocarbon (UHC) and carbon monoxide (CO). Following the initial demonstration of catalytically stabilized thermal combustion by Pfefferle [1,2] in 1970s, theoretical and experimental work [3 14] has been undertaken in this field and led to the conclusion that catalytic combustion was possible to make methane completely combust in the whole range of concentration. Because heterogeneous oxidation of hydrocarbons on the surface of catalysts in the monolith has relatively lower activation energy than that of the homogenous counterpart.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air

Liu

et al. 2007

Chinese Journal of Chemical Engineering

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In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC), NO x and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied. Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50 , 100 and 200 . The results show ed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NO x emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NO x emission was slightly increased.

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“…In CST of diffusionally imbalanced fuels with Lewis numbers Le Ͻ 1 (e.g., H 2 ), the catalyst can reach superadiabatic temperatures, which are more pronounced at the upstream channel locations (see Ref. [12]). Such operation compounded the experiments, since-as tests revealed-the flame anchored directly at the hot entrance.…”

Section: Burner Geometrymentioning

confidence: 99%

An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

Appel

Mantzaras

Schaeren

et al. 2002

Proceedings of the Combustion Institute

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The turbulent catalytically stabilized combustion (CST) of fuel-lean hydrogen/air mixtures over platinum was investigated experimentally and numerically in channel-flow configurations. Experiments were performed in an optically accessible catalytic channel reactor, established by two Pt-coated ceramic plates 300 mm long and placed 7 mm apart, with incoming Reynolds numbers of 15,000 and 30,000. Planar laserinduced fluorescence of the OH radical was used to monitor the onset of homogeneous (gas-phase) ignition, one-dimensional (across the 7 mm transverse direction) Raman measurements of major species and temperature assessed the turbulent scalar transport, laser doppler velocimetry yielded the inlet velocity and turbulence, and thermocouples embedded beneath the catalyst provided the surface temperature distribution. Computations were carried out with a two-dimensional elliptic fluid mechanical code that included elementary heterogeneous and homogeneous chemical reaction schemes. Three different low-Reynolds number near-wall turbulence models were examined, in conjunction with a thermochemistry model that included a presumed-shape (Gaussian) probability density function approach for the gaseous reactions and a laminar-like closure for catalytic reactions. Comparisons between predictions and measurements have shown that key CST issues, such as catalytic fuel conversion and onset of homogeneous ignition, are strongly dependent on the particular turbulence model. Moreover, the discrepancies between predictions and measurements were ascribed to the capacity of the various turbulence models to capture the strong flow laminarization induced by the heat transfer from the hot catalytic surfaces. A turbulence model that yields good agreement with the measurements is presented as particularly suited for CST. Experiments and predictions have shown that a continuous increase of the turbulent transport led to incomplete combustion through the gaseous reaction zone with subsequent catalytic conversion of the leaked fuel and, finally, to extinction of the gaseous flame.

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Catalytically stabilized combustion

Cited by 124 publications

References 36 publications

Catalytic Combustion of Hydrogen-Air Mixtures Over Platinum: Validation of Hetero/Homogeneous Chemical Reaction Schemes

Catalytic Combustion of Hydrogen-Air Mixtures Over Platinum: Validation of Hetero/Homogeneous Chemical Reaction Schemes

Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air

An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

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