Alumina: Catalyst and Support. XIV. Dehydrogenation, Dehydrocyclization and Isomerization of C5- and C6-Hydrocarbons over Chromia-Alumina Catalysts

1962 ◽  
Vol 84 (2) ◽  
pp. 292-297 ◽  
Author(s):  
Herman. Pines ◽  
Sigmund M. Csicsery
Keyword(s):  
Alumina Catalyst ◽  
Alumina Catalysts

Electrocatalytic hydrogenation of octyl aldehyde over Pd catalysts

2007 ◽  
Vol 85 (7-8) ◽  
pp. 475-478
Author(s):  
Ciprian M Cirtiu ◽  
Hugues Ménard
Keyword(s):  
Aqueous Ethanol ◽  
Supporting Electrolyte ◽  
Catalyst Support ◽  
Current Intensity ◽  
Electrocatalytic Hydrogenation ◽  
Alumina Catalyst ◽  
Pd Catalysts ◽  
Alumina Catalysts

The electrocatalytic hydrogenation (ECH) of octyl aldehyde (octanal) to octyl alcohol (octan-1-ol) was investigated using commercial Pd/alumina catalysts in aqueous ethanol. The influence of different parameters, such as catalyst support, current intensity, polarity of solvent, supporting electrolyte, and octanal concentration, on the electrocatalytic hydrogenation of octanal was studied.Key words: octanal, octan-1-ol, Pd/alumina catalyst, electrocatalytic hydrogenation.

Dehydrogenation of 3-carene in the vapour phase. II. Performance studies of chromia and chromia-alumina catalysts

1980 ◽  
Vol 33 (6) ◽  
pp. 1313 ◽  
Author(s):  
V Krishnasamy
Keyword(s):  
Water Vapour ◽  
Performance Studies ◽  
Active Sites ◽  
Vapour Phase ◽  
Progressive Increase ◽  
Oxidation States ◽  
Side Reactions ◽  
Potassium Ions ◽  
Alumina Catalyst ◽  
Alumina Catalysts

The influence of contact time on the dehydrogenation of 3-carene over reduced chromia and chromia-alumina catalysts has been investigated at 450 and 400°C respectively. For the dehydrogenation, reduced chromia- alumina catalyst is more active than reduced chromia alone. It has been found that the dehydrogenating ability of reduced chromia is superior to that of oxidized chromia. The effect of water vapour on reduced chromia showed an initial suppression of its reactivity, but at intermediate values increased its activity. Progressive increase of water vapour was seen to modify the active sites of reduced chromia, an effect similar to that of the oxidized sample. ��� The dehydrogenation of 3-carene, over chromia, follows second-order kinetics. The energy of activation is found to be greater for oxidized than for reduced chromia. Impregnation of chromia with potassium decreases the activation energy of reduced chromia and enhances its dehydrogenation ability by suppressing the side reactions. ��� The observed experimental data are explained in terms of the acidity of the catalysts, oxidation states of chromium ions and the promoting influence of potassium ions.

Experimental Investigations of Catalytic Combustion for High-Pressure Gas Turbine Applications

2006 ◽  
Author(s):  
Jeevan Jayasuriya ◽  
Arturo Manrique ◽  
Reza Fakhrai ◽  
Jan Fredriksson ◽  
Torsten Fransson
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Test Facility ◽  
Experimental Investigations ◽  
Alumina Catalyst ◽  
Fuel Conversion ◽  
Operational Data ◽  
Alumina Catalysts

Catalytic combustion has proven to be a suitable alternative to conventional flame combustion in gas turbines for achieving Ultra-Low Emission levels (ULE). In the process of catalytic combustion, it is possible to achieve a stable combustion of lean fuel/air mixtures which results in reduced combustion temperature in the combustor. The ultimate result is that almost no thermal-NOx is formed and the emissions of carbon monoxide and hydrocarbon emissions are reduced to single-digit limits. Successful development of catalytic combustion technology would lead to reducing pollutant emissions in gas turbines to ultra-low levels at lower operating costs. Since the catalytic combustion prevents the pollutant formations in the combustion there is no need for costly emission cleaning systems. High-quality experimental data of combustion catalyst operations at gas turbine working conditions and validated numerical models are essential tools for the design and development of catalytic gas turbine combustors. The prime objective of the work presented in this paper was to obtain catalytic operational data under said conditions. Experimental investigations were carried out to determine the operational data on different types of combustion catalysts against different fuel types at gas turbine operational conditions. A pilot-scale 100 k W high-pressure combustion test facility was used for the experimental investigations of catalytic combustion under real gas turbine conditions. Combustor pressure can be maintained at any desired level between 1 to 35 bars. The maximum combustion air supply is 100 g/s, which can be electrically preheated up to 600°C and humidified up to 30% of weight as required by test conditions. Catalysts used in the test facility are highly active noble metal catalysts for ignition purposes and thermally stable metal oxide catalysts for continuing reactions. Tests are conducted as the testing of single catalyst segments or combinations of several segments. The measurements taken are flow rates (air/fuel ratio) temperatures (inlet, surface and the outlet of each catalyst segment), pressure (combustor) and emissions of NOx, CO and UHC. This paper presents the design of the high-pressure catalytic combustion test facility and an experimental comparison of methane combustion over Pd on alumina and Pd/Pt (bi-metal) on alumina catalysts at varying pressure levels up to 20 bars. The catalysts concerned were cylindrical shaped (35 mm in diameter and 20 mm in height) honeycomb type fully coated catalysts. The results showed that the Pt/Pd on alumina catalysts is better in low temperature ignition and combustion stability over the Pd on alumina catalysts. Emission measurements showed that the fuel conversion over the tested Pt/Pd on alumina catalyst was around 10% while fuel conversion over a similar Pd on alumina catalyst (geometry and capacity) was only 4%. Fuel conversion rates showed the tendency to be further reduced (over the same catalysts) against increasing pressure.

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