Kinetics of the reduction of nitrogen oxide and dinitrogen oxide by ammonia on a V2O5/Al2O3 catalyst in the absence of oxygen

1986 ◽  
Vol 51 (11) ◽  
pp. 2528-2536 ◽  
Author(s):  
Milan Čížek ◽  
Vladimír Pour
Keyword(s):  
Nitrogen Oxide ◽  
Oxidation State ◽  
Atmospheric Pressure ◽  
Surface Reaction ◽  
Reduction Of No ◽  
Rate Determining Step ◽  
Langmuir Hinshelwood Mechanism ◽  
Temperature Ranges ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of NO and N2O by ammonia on a V2O5/Al2O3 catalyst (15 mass % V2O5) have been measured over the temperature range 300-480 °C at atmospheric pressure. The presence of water vapour in the reaction mixture retards the reduction rates of both NO and N2O. The oxidation state of vanadium does not change within the concentration and temperature ranges investigated. From the results for the reaction kinetics and the oxidation state of vanadium it is concluded that the reduction of NO and N2O by ammonia occurs by the associative Langmuir-Hinshelwood mechanism with the surface reaction as the rate-determining step.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Analytical Treatment of a Heterogeneous Reaction

1998 ◽  
Vol 05 (02) ◽  
pp. 545-550
Author(s):  
J. L. Vicente ◽  
A. Maltz ◽  
E. E. Mola
Keyword(s):  
Surface Reaction ◽  
Heterogeneous Reaction ◽  
Heterogeneous Catalytic Reaction ◽  
Analytical Treatment ◽  
Heterogeneous Catalytic ◽  
A Value ◽  
Large N ◽  
Rate Of Reaction ◽  
Langmuir Hinshelwood Mechanism ◽  
Kinetics Of

An analytical method has been used to study the kinetics of a generic heterogeneous catalytic reaction, A + B → AB. This reaction includes the elementary steps of adsorption and desorption of reactants A and B, surface reaction through the Langmuir-Hinshelwood mechanism, and desorption of the product AB. Despite its simplicity, this analytical approach shows some of the general features observed by simulating the present mechanism on a large N × N lattice.5–7 The rate of reaction depends on the rate of desorption of reactants with a maximum at a value similar to those found by performing heavy simulations. Coverage fluctuations of reactants, as a function of their rate of desorption on a 2 × 2 lattice, have a behavior similar to that found on large N × N lattices.

Hydrogenation of ethylene on a Co-Mo/Al2O3 catalyst under transient conditions

1986 ◽  
Vol 51 (12) ◽  
pp. 2760-2769
Author(s):  
Jana Samková ◽  
Karel Klusáček ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Total Concentration ◽  
Ethylene Hydrogenation ◽  
Response Curves ◽  
Feed Composition ◽  
Rate Determining Step ◽  
Al2o3 Catalyst ◽  
Adsorbed Ethylene ◽  
Hydrogenation Of Ethylene

Hydrogenation of ethylene on a Co-Mo/Al2O3 catalyst at 353 K and atmospheric pressure has been studied. The unsteady-state method was used, in which reactor feed-rate and feed-composition were changed in a defined way. The analysis of transient response curves proved negligible adsorption of hydrogen and ethane and confirmed the reaction mechanism of ethylene hydrogenation which involves reaction of adsorbed ethylene with hydrogen from gas phase in the rate determining step. Combined stationary and transient experimental data were used to calculate kinetic parameters: rate constant of ethylene hydrogenation, total concentration of active sites on the catalyst surface and equilibrium adsorption coefficient of ethylene.

Kinetics of CO2 Reforming of Methane by Catalytically Activated Metallic Foam Absorber for Solar Receiver-Reactors

2008 ◽  
Author(s):  
Nobuyuki Gokon ◽  
Yusuke Osawa ◽  
Daisuke Nakazawa ◽  
Tsuyoshi Hatamachi ◽  
Tatsuya Kodama
Keyword(s):  
Light Flux ◽  
Metallic Foam ◽  
Small Scale ◽  
Al Alloy ◽  
High Porosity ◽  
Co2 Reforming ◽  
Co2 Reforming Of Methane ◽  
Langmuir Hinshelwood Mechanism ◽  
Kinetics Of ◽  
Al2o3 Catalyst

Ni-Cr-Al alloy foam absorber with high porosity was catalytically activated using a Ru/γ-Al2O3 catalyst, and was subsequently tested with respect to CO2 reforming of methane in a small-scale volumetric receiver-reactor by using a sun simulator. A chemical storage efficiency of about 40% was obtained for a mean light flux of 325 kWm−2. Furthermore, the activity and the stability of the metallic foam absorber were compared with those of a SiC foam absorber activated with the same Ru/γ-Al2O3 catalyst for 50 h of light irradiation, and it was found that the metallic foam absorber has superior catalytic stability in comparison to the SiC form absorber. In addition, unlike ceramic foams such as SiC, metallic foams feature superior plasticity, which prevents the emergence of cracks caused by mechanical or thermal shock. The kinetics of CO2 reforming of methane over metallic foam absorbers were also examined for temperatures of 600–750°C using a quartz tube reactor and an electric furnace. The experiments were performed by varying the methane/CO2 ratios of 0.5–2.3. Moreover, the kinetic data were fitted to four different types of kinetic models, namely the Langmuir-Hinshelwood, Basic, Eley-Rideal, and Stepwise mechanisms. The kinetic model which provided the best prediction of the experimental reforming rates was the Langmuir-Hinshelwood mechanism.

Kinetics of the catalytic hydrodesulphurization reaction system; hydrogenolysis of thiophene

1980 ◽  
Vol 45 (10) ◽  
pp. 2728-2741 ◽  
Author(s):  
Pavel Fott ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Flow Reactor ◽  
Kinetic Equations ◽  
Reaction System ◽  
Reaction Products ◽  
Molybdenum Catalyst ◽  
Cobalt Molybdenum Catalyst ◽  
Kinetics Of ◽  
Reaction Schemes

Kinetics have been studied of the reaction system taking place during the reaction of thiophene on the cobalt-molybdenum catalyst in a gradientless circulation flow reactor at 360 °C and atmospheric pressure. Butane has been found present in a small amount in the reaction products even at very low conversion. In view of this, consecutive and parallel-consecutive (triangular) reaction schemes have been proposed. In the former scheme the appearance of butane is accounted for by rate of desorption of butene being comparable with the rate of its hydrogenation. According to the latter scheme part of the butane originates from thiophene via a different route than through hydrogenation of butene. Analysis of the kinetic data has revealed that the reaction of thiophene should be considered to take place on other active sites than that of butene. Kinetic equations derived on this assumption for the consecutive and the triangular reaction schemes correlate experimental data with acceptable accuracy.

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