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A. Pattek

Bio: A. Pattek is an academic researcher from Jagiellonian University. The author has contributed to research in topics: Catalysis & Ammonia production. The author has an hindex of 4, co-authored 5 publications receiving 48 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the validity of the core-and-shell reduction model, assuming a Langmuir-Hinshelwood kinetic equation which describes the reaction at the oxide/iron interface, is discussed on the basis of the kinetic data for unpromoted and promoted iron catalysts.

14 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the kinetics of reduction of an iron catalyst at 450-550 °C and showed that the surface reaction was of the Langmuir-Hinshelwood type with the adsorption of only water vapor.
Abstract: The kinetics of reduction of an iron catalyst have been studied at 450–550 °C. The overall kinetic equation was of the “mixed-control” type. The equation of the surface reaction was of the Langmuir-Hinshelwood type with the adsorption of only water vapor taken into account.

13 citations

Journal ArticleDOI
TL;DR: In this article, the reduction of an iron catalyst of KM I type by a hydrogen:nitrogen (3:1) gas mixture containing 2,600 − 10,000 ppm of water vapour was studied thermogravimetrically at 500°C.

11 citations

Book ChapterDOI
TL;DR: In this article, a core-and-shell model was proposed for the reduction of nonporous magnetite particles with hydrogen to yield the internal porous structure of the iron catalyst, where the gas-solid reaction proceeds on the interface between the core and shell.
Abstract: The activation of ammonia catalysts is essentially a reduction of non-porous magnetite particles with hydrogen to yield the internal porous structure of the iron catalyst. The reduction is studied by means of a “core-and-shell” model where the gas-solid reaction proceeds on the interface between the core and shell. Effective diffusion coefficients are calculated from experimental pore size distribution measurements. Different reaction rate expressions were tested on experimental reduction curves for cases with and without water addition, and it is shown that it is necessary to include the adsorption of water in the rate expression. Finally, some limitations in the model are described.

8 citations

Journal ArticleDOI
TL;DR: In this paper, les etudes s'effectuaient sur deux catalyseurs contenant des quantites differentes (4 % and 27 %) of wustite.
Abstract: Resume. — L'article presente des etudes Mossbauer de l'activation (reduction) de catalyseurs de commerce, bases sur magnetite et frequemment promotes, pour la synthese de l'ammoniac. Les etudes s'effectuaient sur deux catalyseurs contenant des quantites differentes (4 % et 27 %) de wustite. Le procede de reduction fut suivi de spectroscopie Mossbauer in situ permettant une etude des cinetiques de reduction. On a trouve que la phase wustite est reduite plus vite que la magnetite. Seulement le catalyseur qui retient la quantite moindre de wustite se trouvait reduit selon le modele noyau-et-coquille. Une comparaison avec des observations microscopiques elucide les desaccords susmentionnes. En contraste avec l'etude prealable de catalyseurs singulierement promotes, on a trouve sous conditions operatoires la presence de fer non reduit.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, temperature-programmed reduction was used to characterize precipitated iron oxide samples and two-stage reduction was observed: Fe2O3 was reduced to Fe3O4 and then reduced to metallic Fe.

272 citations

Journal ArticleDOI
TL;DR: In this paper, temperature-programmed reduction (TPR) was used for two-stage reduction of cobalt catalysts supported on silica, and the activation energies for the two reduction steps were 94.43 and 82.97 kJ−mol −1, respectively.

171 citations

Journal ArticleDOI
TL;DR: In this article, the reduction behavior of iron catalysts supported on magnesia or alumina was investigated using in situ high-field magnetization measurements, thermomagnetic analysis, temperature-programmed reduction, and X-ray diffraction.

133 citations

Journal ArticleDOI
TL;DR: In this article, a complete description of the kinetics of metal oxide reduction can be found, which can be critical to the successful choice of catalase for a given reaction cycle.
Abstract: As metal oxide reduction may be a limiting or otherwise important step in a reaction cycle, a complete description of the kinetics of the reduction can be critical to the successful choice of catal...

76 citations

Reference EntryDOI
15 Oct 2011
TL;DR: In this paper, the authors describe the process steps of ammonia production, including feedstock pretreatment and raw gas production, and demonstrate the effect of pressure and other variations of the synthesis loop.
Abstract: The article contains sections titled: 1. Introduction 2. Historical Development 3. Thermodynamic Data 4. Ammonia Synthesis Reaction 4.1. General Aspects 4.2. Catalyst Surface and Reaction Mechanism 4.3. Kinetics 5. Catalysts 5.1. Classical Iron Catalysts 5.1.1. Composition 5.1.2. Particle Size and Shape 5.1.3. Catalyst-Precursor Manufacture 5.1.4. Catalyst Reduction 5.1.5. Catalyst Poisons 5.2. Other Catalysts 5.2.1. General Aspects 5.2.2. Metals with Catalytic Potential 5.2.3. Commercial Ruthenium Catalysts 6. Process Steps of Ammonia Production 6.1. Synthesis Gas Production 6.1.1. Feedstock Pretreatment and Raw Gas Production 6.1.2. Carbon Monoxide Shift Conversion 6.1.3. Gas Purification 6.2. Compression 6.3. Ammonia Synthesis 6.3.1. Synthesis Loop Configurations 6.3.2. Formation of Ammonia in the Converter 6.3.3. Waste-Heat Utilization and Cooling 6.3.4. Ammonia Recovery from the Ammonia Synthesis Loop 6.3.5. Inert-Gas and Purge-Gas Management 6.3.6. Influence of Pressure and Other Variables of the Synthesis Loop 6.3.7. Example of an Industrial Synthesis Loop

61 citations