Papers by Iacovos Vasalos
Studies in Surface Science and Catalysis
... Chem. Soc., 114 (1992), 10834-10843. 2. Sayari, A., Chem. Mater., 8 (1996), 1840-1852. 3. Cor... more ... Chem. Soc., 114 (1992), 10834-10843. 2. Sayari, A., Chem. Mater., 8 (1996), 1840-1852. 3. Corma, A., Chem. Rev., 97 (1997), 2373-2419. ... 20. Ryoo, R., Kim, MJ, Kim, JM, Jun, S., Chem. Commun., (1997), 2225-2226. 21. Biswas, J., Maxwell, IE, Appl. Catal., 58 (1990), 1-18. 22. ...
Kinetic experiments for the selective catalytic reduction (SCR) of NO with C3H6 were performed on... more Kinetic experiments for the selective catalytic reduction (SCR) of NO with C3H6 were performed on two Rh/alumina catalysts with different metal loading, namely 0.5wt.% and 2.0wt.% Rh, so as to examine the effect of metal loading on the SCR performance of Rh/alumina catalysts. The experimental results show a strong positive effect of metal loading on the NO reduction activity of
The increasing need for upgrading heavier petroleum fractions towards the production of valuable ... more The increasing need for upgrading heavier petroleum fractions towards the production of valuable liquid and gaseous fuels induced the necessity for the development of novel catalytic materials with improved structural and porosity characteristics. Since the discovery of the nanostructured mesoporous M41S (MCM-41, MCM-48) materials from Mobil in 1992, there is a significant research effort towards the improvement of the low
Industrial Engineering Chemistry Research, 1992
Ind Eng Chem Res, 2004
ABSTRACT
Applied Catalysis, 1989
Various types of catalyst samples selective for the production of ethylene via steam cracking wer... more Various types of catalyst samples selective for the production of ethylene via steam cracking were prepared. Controlled ratios of two or more oxides and high calcination temperatures were used in order to obtain the desired crystal phases, BET surface-area measurement and X-ray diffraction techniques were used for the examination of the samples. The prepared samples were tested in an experimental pyrolysis unit using n-hexane as a feed. It was found that a catalyst with the formula 12CaO-7A1203 has the highest selectivity ratios. The catalyst activity varied widely depending on the operating conditions. At short residence times the catalyst increases the conversion of the feed and hence the olefin yields compared with "inert" a-alumina and thermal cracking (empty reactor). At relatively long residence times and high hydrocarbon partial pressure the catalyst promotes the formation of carbon oxides. Therefore, with a judicious choice of the operating conditions, the catalyst 12CaO-7A1,03 can act as a steam cracking and/or a steam reforming catalyst. Testing of a sample following treatment with hydrogen at high temperature showed no catalytic activity. It is believed that the increased catalyst activity is due to the excess of oxygen that exists in the crystal phase Ca,2Al,,0,, of the 12CaO-7A1,03 catalyst.
Appl Catal B Environ, 2003
Catalyst evaluation and kinetic analysis was performed on the catalytic decomposition of N2O to N... more Catalyst evaluation and kinetic analysis was performed on the catalytic decomposition of N2O to N2 over a Ru/Al2O3. An oxygen rich feed containing SO2 and H2O were used in order to examine their influence on the catalyst activity. An Al2O3 support was used with various Ru loadings (1–4%). No enhancement in the activity was observed for Ru loadings higher than
Catalysis Today, Jul 15, 2009
Energy Fuels, Jul 6, 2006
ABSTRACT Hydrogen produced from renewable energy sources is of great interest as an alternative t... more ABSTRACT Hydrogen produced from renewable energy sources is of great interest as an alternative to fossil fuels and as a means for power generation via fuel cells. The aqueous fraction of bio-oil can be effectively reformed to hydrogen-rich streams in the presence of active catalytic materials. In this paper, we present the experimental work carried out in a fixed bed reactor for the reforming of bio-oil. The performance of the reactor was studied at various conditions and compared to the values theoretically predicted by thermodynamic equilibrium. The effect of reaction temperature, steam-to-carbon ratio in the feed, and space velocity was investigated in the presence of a commercial nickel catalyst. Runs were conducted with acetic acid, acetone, and ethylene glycol, representative model compounds of bio-oil, and the aqueous phase of a real bio-oil derived from beech wood. The results of the selected model compounds show that all can be effectively reformed with hydrogen yields up to 90% at reaction temperatures higher than 600 °C and steam-to-carbon ratios higher than 3. The reforming of the aqueous fraction of bio-oil proved to be more difficult, with the hydrogen yield fluctuating at about 60%. The most serious problem encountered in these experiments is coking. The formation of carbonaceous deposits in the upper part of the catalyst zone limits the reforming time and necessitates frequent regeneration of the catalyst.
Applied Catalysis a General, 2002
Methane reforming by carbon dioxide was investigated over 5wt.% Ni/CaO-Al2O3 catalyst. X-ray diff... more Methane reforming by carbon dioxide was investigated over 5wt.% Ni/CaO-Al2O3 catalyst. X-ray diffraction (XRD) and temperature-programmed reduction (TPR) techniques were applied to characterise the catalyst. The catalyst exhibited high activity and very good stability at stoichiometric methane and carbon dioxide feed. The addition of steam in the reacting mixture was tested and proved beneficial for the conversion of methane and
Catal Today, 1998
NO reduction experiments were carried out in a ®xed-bed reactor loaded with metal/alumina catalys... more NO reduction experiments were carried out in a ®xed-bed reactor loaded with metal/alumina catalysts. Two hydrocarbons, methane and propene, were used as the reducing agents for the NO reduction. The former hydrocarbon exhibited relatively low NO x conversions and it was burned at high temperatures. The addition of methane to a propene-containing feed gas stream did not cause any inhibition or enhancement on the NO reduction activity over the Pt/alumina catalyst. The presence of water in the feed gas stream caused a small, reversible, inhibition effect over the Pt/, Cu/ and Ni/alumina catalysts. The maximum NO conversion was measured over Ni/alumina, followed by that over Cu/and Pt/alumina. The peak temperature varied with the catalyst, but it was not affected by the addition of water to the feed gas stream. The presence of SO 2 in the feed gas stream did not affect the NO x conversion over Pt/alumina, it caused a signi®cant irreversible loss of activity over other metal/alumina catalysts and it enhanced the activity of Rh/alumina.
Industrial Engineering Chemistry Research, 1990
A process is claimed for fluid catalytic cracking of residuum and other heavy oils comprising of ... more A process is claimed for fluid catalytic cracking of residuum and other heavy oils comprising of gas oil, petroleum residue, reduced and whole crudes and shale oil to produce gasoline and other liquid products which are separated in various streams in a fractionator and associated vapor recovery equipment. The heat from combustion of coke on the coked catalyst is removed by reacting sulfur-containing coke deposits with steam and oxygen in a separate stripper-gasifier to produce a low btu gas stream comprising of sulfur compounds, methane, carbon monoxide, hydrogen, and carbon dioxide at a temperature of from about 1100°F. To about 2200°F. The partially regenerated catalyst then undergoes complete carbon removal in a regeneration vessel. The regenerated catalyst is recycled for re-use in the cracking of heavy petroleum fractions. The liquid products are gasoline, distillates, heavy fuel oil, and light hydrocarbons.
Journal of Catalysis, 1995
Industrial & Engineering Chemistry Research, 2004
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Papers by Iacovos Vasalos