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1
Content available remote Dekarbonizacja metanu z udziałem katalizatorów na bazie żelaza
Wojtasik Michał, Żak Grażyna, Markowski Jarosław, Burnus Zygmunt, Krasodomski Wojciech, Pakieła Wojciech
Przemysł Chemiczny
|
2023
|
T. 102, nr 3
259--263
PL
Zbadano wpływ dwóch prostych, łatwo dostępnych i tanich katalizatorów żelazowych, tlenku żelaza i wiórków stalowych. Dla procesów katalitycznych oraz porównawczo dla procesu termicznego zbadano składy gazów poprocesowych w temp. 600, 750, 850, 950C i 1050°C. W gazach poprocesowych oznaczono zawartość metanu, wodoru, azotu, tlenu i sumy węglowodorów C₂ i C₃ za pomocą GC. Dla poszczególnych procesów wyznaczono konwersję metanu. Węgiel powstający w procesie zobrazowano metodą SEM i EDS i oceniono stopień jego grafityzacji za pomocą spektroskopii Ramana.
EN
MeH was thermally or catalytically pyrolyzed in the presence of Fe₂O₃ or steel shavings at temp. of 600, 750, 850, 950 and 1050°C. In the post-process gases, the content of MeH, H₂, N₂, O₂ and the sum of C₂ and C₃ hydrocarbons were detd. by GC and the conversion of MeH was calculated. The C formed in the process were analyzed and imaged by SEM and EDS. The degree of graphitization of the C was evaluated by Raman spectroscopy.
2
Content available remote Katalizator żelazowy do syntezy amoniaku
Lubkowski Krzysztof, Ściążko Andrzej
Przemysł Chemiczny
|
2020
|
T. 99, nr 2
270--277
PL
Przedstawiono w sposób syntetyczny dorobek badawczy, jaki został zgromadzony w obszarze zagadnień związanych z syntezą amoniaku, w szczególności ten, który dotyczy wytwarzania i struktury katalizatora żelazowego, a także metod oraz warunków jego redukcji i pasywacji.
EN
Fundamentals and a review with 164 refs.
3
Content available remote Wpływ katalizatora żelazowego na efektywność spalania oleju napędowego w silniku wysokoprężnym
Tic W. J.
Przemysł Chemiczny
|
2018
|
T. 97, nr 9
1520--1522
PL
Zastosowanie katalizatora żelazowego do modyfikacji oleju napędowego nie wpływa w sposób istotny na zużycie paliwa w testach spalania. Zauważalny jest jednak korzystny wpływ dodatku katalizatora na obniżenie emisji szkodliwych składników spalin, takich jak CO i CO2. Wpływ ten jest szczególnie widoczny dla większych obciążeń silnika. W przypadku emisji węglowodorów, korzystny wpływ katalizatora widoczny jest dla obciążeń silnika w zakresie 15-30 kW. Zarówno większe, jak i mniejsze obciążenie silnika powoduje wzrost emisji węglowodorów w spalinach w porównaniu z próbami spalania paliwa bez dodatku katalizatora.
EN
Com. gas oil was modified by addn. of a Fe catalyst consisting of a Fe soap and Fe(OH)3 (0.01% by mass) and tested for CO, CO2 and hydrocarbon emissions during combustion in a self-ignition engine (10-30 kW). Addn. of the catalyst resulted in a significant redn. of CO and hydrocarbon contents in the of-gases (at engine load 20–30 kW) and a decrease in the oil consumption.
4
Content available The activity of fused-iron catalyst doped with lithium oxide for ammonia synthesis
Jedrzejewski R., Lendzion-Bieluń Z., Arabczyk W.
Polish Journal of Chemical Technology
|
2016
|
Vol. 18, nr 2
78--83
EN
The iron catalyst precursor promoted with Al2O3, CaO, and Li2O was obtained applying the fusing method. Lithium oxide forms two phases in this iron catalyst: a chemical compound with iron oxide (Li2Fe3O4) and a solid solution with magnetite. The catalyst promoted with lithium oxide was not fully reduced at 773 K, while the catalyst containing potassium was easily reducible at the same conditions. After reduction at 873 K the activity of the catalyst promoted with lithium oxide was 41% higher per surface than the activity of the catalyst promoted with potassium oxide. The concentration of free active sites on the surface of the catalyst containing lithium oxide after full reduction was greater than the concentration of free active sites on the surface of the catalyst promoted with potassium oxide.
5
Content available remote Synteza 2,6-dimetylofenolu w reakcji alkilacji fenolu metanolem w fazie gazowej na katalizatorach żelazowych
Łysik P., Górska A., Szarlik S.
Przemysł Chemiczny
|
2013
|
T. 92, nr 5
685-687
6
Content available remote Badanie procesu azotowania katalizatora żelazowego
Kiełbasa K., Wilk B., Arabczyk W.
Przemysł Chemiczny
|
2013
|
T. 92, nr 5
859-861
7
Content available Studies of the Ammonia Decomposition over a Mixture Of α - Fe(N) And γ' - Fe4n
Kiełbasa K., Arabczyk W.
Polish Journal of Chemical Technology
|
2013
|
Vol. 15, nr 1
97-101
EN
An industrial pre-reduced iron catalyst for ammonia synthesis was nitrided in a differential reactor equipped with the systems that made it possible to conduct both the thermogravimetric measurements and hydrogen concentration analyser in the reacting gas mixture. The nitriding process, particularly the catalytic ammonia decomposition reaction, was investigated under an atmosphere of ammonia-hydrogen mixtures, under the atmospheric pressure, at 475oC. The nitriding potentials were changed gradually in the range from 19.10-3 to 73.10-3 Pa-0.5 in the reactor for an intermediate area where two phases exist simultanously: Fe(N) and γ’-Fe4. In the area wherein P > 73.10-3 Pa-0.5, approximately stoichiometric composition of γ’ - Fe4N phase exists and saturating of that phase by nitrogen started. The rate of the catalytic ammonia decomposition was calculated on the basis of grain volume distribution as a function of conversion degree for that catalyst. It was found that over γ’ - Fe4N phase in the stationary states the rate of catalytic ammonia decomposition depends linearly on the logarithm of the nitriding potential. The rate was decreasing along with increase in the nitriding potential. For the intermediate area, the rate of ammonia decomposition is a sum of the rates of reactions which occur on the surfaces of both Fe(N) and γ’ - Fe4N.
8
Content available Determination of the Content of Promoters in Magnetite and Wustite Phases in the Fused Iron Catalyst
Lendzion-Bieluń Z., Jędrzejewski R.
Polish Journal of Chemical Technology
|
2013
|
Vol. 15, nr 1
27-29
EN
Taking advantage of differences in etching rates of crystallographic phases, forming an oxidized form of the fused iron catalyst, a content of promoters in main phases, magnetite and wustite, was determined. A calcium oxide content in magnetite and wustite was 0.54 wt% and 3.59 wt%, respectively. Aluminum oxide was found in the magnetite phase, and its content was 4.5 wt%. The third promoter, potassium oxide, was almost completely located outside these phases. XRD and ICP-OES instrumental methods were used in the investigations.
9
Content available Preparation of carbon nanotubes using cvd CVD method
Pełech I.
Polish Journal of Chemical Technology
|
2010
|
Vol. 12, nr 3
45-49
EN
In this work preparation and characteristic of modified nanocarbons is described. These materials were obtained using nanocrystalline iron as a catalyst and ethylene as a carbon source at 700°C. The influence of argon or hydrogen addition to reaction mixture was investigated. After ethylene decomposition samples were hydrogenated at 500°C. As a results iron carbide (Fe3C) in the carbon matrix in the form of multi walled carbon nanotubes was obtained. After a treatment under hydrogen atmosphere iron carbide decomposed to iron and carbon and small iron particles agglomerated into larger ones.
10
Content available remote Utlenianie a pasywacja materiałów nanokrystalicznych
Jasińska I., Ekiert E., Pelka R., Lubkowski K., Arabczyk W.
Przemysł Chemiczny
|
2009
|
T. 88, nr 5
462-467
11
A Comparison of the Distribution of Promoters in Reduced and Oxidized Form of Iron Catalyst in Reduced and Oxidized Form of Iron Catalyst for Ammonia Synthesis
Lendzion-Bieluń Z.
Polish Journal of Chemistry
|
2007
|
Vol. 81, nr 3
433-440
EN
The distribution of promoters in the reduced form of iron catalyst for the ammonia synthesis was studied using the selective etching method and the electron microscopy technique with EDX analyzer. During the reduction process, calcium and aluminium incorporated into amagnetite particle, do not migrate but they form the CaOźAl2O3 phase. It was found that approximately 30% of the total amount of aluminium is separated in the Al2O3 form.
12
Content available Utilization of spent iron catalyst for ammonia synthesis
Arabczyk W., Narkiewicz U., Lendzion-Bieluń Z., Moszyński D., Pełech I., Ekiert E., Podsiadły M., Pelka R., Jędrzejewski R., Moszyñska I., Sibera D.
Polish Journal of Chemical Technology
|
2007
|
Vol. 9, nr 3
108-113
EN
Several methods of the utilization of spent iron catalyst for ammonia synthesis have been presented. The formation of iron nitrides of different stoichiometry by direct nitriding in ammonia in the range of temperatures between 350°C and 450°C has been shown. The preparation methods of carbon nanotubes and nanofibers where iron catalyst catalyse the decomposition of hydrocarbons have been described. The formation of magnetite embedded in a carbon material by direct oxidation of carburized iron catalyst has been also presented.
13
Content available remote Obecny stan wiedzy o katalizatorze żelazowym do syntezy amoniaku
Arabczyk W., Jasińska I.
Przemysł Chemiczny
|
2006
|
T. 85, nr 2
130-137
PL
Na podstawie doniesień literaturowych oraz wyników prac własnych opisano obecny stan wiedzy o katalizatorze żelazowym do syntezy amoniaku. Przedstawiono model powierzchni aktywnej katalizatora żelazowego, w którym założono, że powierzchnia żelaza jest zwilżona tlenkami promotorów oraz, że katalizator w warunkach syntezy amoniaku znajduje się w stanie równowagi. W oparciu o zaproponowany model wyjaśniono mechanizm redukcji oraz dezaktywacji katalizatora.
EN
A review with 78 refs. covering the mechanism of redn. and deactivation of iron catalysts in terms of a catalyst model with the active iron atom surface assumed to be wetted by promoters oxides. Promoters join with the Fe atom via O atom. At >350°C, chem. equil. is rapidly attained in the nanocryst. systems.
14
The Influence of Hydrogen Sulphide on the Kinetics of Ammonia Decomposition over a Doubly Promoted Iron Catalyst
Arabczyk W., Zamłynny J., Moszyński D.
Polish Journal of Chemistry
|
2006
|
Vol. 80, nr 2
345-350
EN
The kinetics of ammonia decomposition over an iron catalyst poisoned with sulphur has been studied. The relative activity of this catalyst decreases with increasing concentration of sulphur and increases with increasing temperature. As the simple site-blocking mechanism of poisoning cannot explain this behaviour, the formation of stable sulphur compounds and the evolution of the catalysts' active surface with the temperature was proposed to account for the results.
15
Content available remote Ocena aktywności żelazowych katalizatorów syntezy amoniaku w przemysłowych reaktorach typu TVA
Mordecka Z., Woźniak S.
Przemysł Chemiczny
|
2005
|
T. 84, nr 12
946-948
PL
Analizowano proces dezaktywacji żelazowych katalizatorów syntezy amoniaku w przemysłowych reaktorach typu TVA. Rozpatrzono kilka różnych modeli dezaktywacji katalizatora wzdłuż wysokości złoża, wykorzystując wyniki badania aktywności próbek katalizatora pobranych w czasie wyładunku starannie spasywowanego wsadu. Modele te zastosowano następnie do oceny pracy reaktora. Za pomocą wybranego modelu oceniono szybkość dezaktywacji katalizatora PS3-INS, na podstawie parametrów technologicznych z okresu jego 12-letniej eksploatacji w reaktorze TVA, w jednostce syntezy amoniaku o zdolności produkcyjnej 500 t/d, w ZA „Puławy”.
EN
In an 8–12 mm PS-3-INS catalyst thoroughly passivated and discharged from the reactor, structural promoters (Al, Ca, Mg, Si) were unaffected, S was present in the top layer, and K losses were 26% in the top and up to 10% in other layers. In mid-layers, Fe crystallite size growth was max. Reactor’s operating lines were calcd. by assuming various catalyst activity variation models, plug flow of the gas through the bed, and the exptl. kinetic characteristics of the catalyst. Most affected were temp. profiles; ammonia production only in 2%. The catalyst activity drop, only 30% in a 12-year-long operation of a 500-t NH3/day plant, was attributed to catalyst’s thermal stability and high purity of the synthesis gas.
16
Content available remote The state of studies on iron catalyst for the ammonia synthesis
Arabczyk W.
Polish Journal of Chemical Technology
|
2005
|
Vol. 7, nr 3
8-17
EN
The past and present research of the iron catalyst for ammonia synthesis carried out in the Institute of Chemical and Environment Engineering of Szczecin University of Technology has been described. The role of promoters, especially alkali metals, has been explained. The structure of the surface of active iron catalyst has been proposed. The behavior of iron catalyst during the reaction of nitriding has also been shown.
17
Content available remote Wpływ temperatury redukcji na powierzchnię właściwą i aktywną preredukowanego katalizatora żelazowego do syntezy amoniaku
Jasińska I., Lubkowski K., Arabczyk W.
Przemysł Chemiczny
|
2003
|
T. 82, nr 3
230-233
18
Content available remote The effect of alkali metals on the surface area of iron catalyst for ammonia synthesis
Jasińska I., Moszyński D., Arabczyk W., Kaleńczuk R.
Polish Journal of Chemical Technology
|
2003
|
Vol. 5, nr 4
70-72
EN
The surface area of the iron catalyst for ammonia synthesis impregnated with lithium, sodium, potassium and cesium was examined. The concentration of the respective element (expressed in mole fraction) in the bulk of the catalyst sample was varied from near zero to 1.5-10~3. The increase in the concentration of the promoter led to the decrease of the surface area of the catalyst regardless of the element present in the bulk. The exponential equation has been proposed to describe this dependence. The empirical factor AM o from the mentioned equation, which differs from element to element, was correlated with the difference between the formation enthalpy of A12O3 and the respective alkali metal oxide. The observed dependence obeys a linear law.
19
Content available remote Studies of the kinetics of CH4 decomposition to Fe3C on the promoted iron catalysts
Arabczyk W., Narkiewicz U., Konicki W., Grzmil B.
Polish Journal of Chemical Technology
|
2002
|
Vol. 4, nr 3
1-4
EN
The decomposition of methane on the doubly- (A1,O,, CaO) and triply- (K,O, A1,O,, CaO) promoted iron catalyst has been investigated using the thermobalance (considered as an differential reactor). The process of decomposition results in the formation of iron carbide and carbon deposit subsequently. The process was carried out under atmospheric pressure in the temperature range of 500 - 600°C. The rate of Fe3C formation in the kinetic region of the reaction was written using the following expression: r = k-pCH . The apparent activation energy of methane decomposition to Fe,C is equal to 158 kJ/mol for both doubly and triply promoted iron catalysts. The pre-exponential factor k() equals to 1.77-10* and 5.71 105 for doubly and triply promoted catalyst, respectively.
20
Content available remote On the reduction of iron catalyst for ammonia synthesis
Arabczyk W., Moszyński D., Jasińska I.
Polish Journal of Chemical Technology
|
2002
|
Vol. 4, nr 4
1-5
EN
The influence of the potassium concentration change on the surface area and active surface of an iron catalyst for ammonia synthesis was studied. The removal of potassium leads to the increase of the surface area, while potassium addition gives rise to the decrease of the surface area which is accompanied by the fourfold increase of the active area. The mechanism of the reduction of iron catalyst was proposed. A special attention was paid to the role of promoters. First, the reduction of iron oxides leads to the formation of porous structure with a well-developed surface area. It is due to the formation of aluminium and calcium oxides film on the iron surface. This structure thanks to high oxygen content balances the iron surface tension which results in a high surface area. This process is followed by potassium diffusion from the grain boundaries to the crystallite surface. Potassium atoms are more favoured to form stable structure on the iron surface than aluminium and calcium. It leads to the formation of K+O film on the iron surface. Because K+O structure requires less oxygen atoms part of the iron surface is freed. The balance between chemical bonds and surface energy is disturbed and the surface area is lowered. At the same time some number of free adsorption sites are formed giving rise to the increase of active surface and the activation of a catalyst.
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