Kinetics of methanation of carbon monoxide and carbon dioxide.

The power-to-gas process for the chemical storage of renewable energy in methane as a storage molecule requires a carbon source, for which industrial exhaust gases are very promising because of their availability in large quantities. The composition of these gas streams, however, is often characterized by a mixture of CO and CO2. Because of the rather complex reaction mechanism, though, the methanation of CO/CO2 mixtures using nickel catalysts is not yet fully understood, and appropriate reaction kinetics required for the reactor design are still lacking. Therefore, we report the experimental results on the methanation of various mixtures of CO and CO2. The data are further evaluated by a model-based approach in order to derive reaction kinetics capable for the reactor design in a typical range of operating conditions. The results also reveal two kinetic regimes depending on the fraction of CO in the CO/CO2 mixture, which is accounted for in the proposed kinetics.

Section: Motivationmentioning

confidence: 99%

Hydrogenation of CO/CO₂ Mixtures on Nickel Catalysts: Kinetics and Flexibility for Nickel Catalysts

Meyer

Schumacher

Friedland

et al. 2020

“…One possibility for ensuring isothermal conditions during highly exothermic reactions is the use of the catalytic wall reactor (CWR) where the catalyst is directly coated on the wall, thus allowing the temperature of the catalyst to be easily controlled. Because of its isothermal behavior under extreme conditions, the catalytic wall reactor has already been used for kinetic investigations in highly exothermic reactions. − …”

Section: Introductionmentioning

confidence: 99%

“…Because of its isothermal behavior under extreme conditions, the catalytic wall reactor has already been used for kinetic investigations in highly exothermic reactions. [2][3][4][5][6][7] The kinetics of the oxidation of propene to acrolein on bismuth molybdates has already been investigated several times. [8][9][10][11][12][13][14][15][16][17][18][19] The results show major differences in the rate equations and kinetic parameters, which probably can be attributed to deviations in catalyst composition and structure.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Modeling of the Heterogeneously Catalyzed Oxidation of Propene to Acrolein in a Catalytic Wall Reactor

Redlingshöfer

Fischer

Weckbecker

et al. 2003

Using data from isothermal investigations in a catalytic wall reactor (Redlingsho ¨fer, H.; Kro ¨cher, O.; Bo ¨ck, W.; Huthmacher, K.; Emig, G. Ind. Eng. Chem. Res. 2002, 41, 1445, the kinetics of the highly exothermic vapor-phase oxidation of propene was determined by statistical parameter estimation. It was shown that the oxidation of propene to acrolein follows a redox mechanism, with a change in the rate-determining step that depends on temperature. Two kinetic equations for the reduction and reoxidation regimes were necessary for a good fit to the experimental values. About a 3-fold higher activation energy for the reoxidation step and different propene and oxygen concentration dependencies of the rate equations in the two regimes were observed. An increasing water content improves catalyst reoxidation. This special catalytic effect was modeled by including an activity function. The kinetics of the byproducts acrylic acid, carbon oxides, formaldehyde, acetaldehyde, and acetic acid were considered with a reaction scheme consisting of 10 reactions. The model describes the experimental data very well. It includes 31 significant kinetic parameters.

“…This combines the advantages of both plug flow and recycle reactor. For the purpose of kinetic modeling the CWR has already been used in different reaction systems with high reaction enthalpies for collecting isothermal data. − …”

Section: Introductionmentioning

confidence: 99%

Catalytic Wall Reactor as a Tool for Isothermal Investigations in the Heterogeneously Catalyzed Oxidation of Propene to Acrolein

Redlingshöfer

Kröcher

Böck

et al. 2002

The vapor phase oxidation of propene to acrolein is a highly exothermic reaction. To ensure isothermal reaction conditions, a catalytic wall reactor was used for detailed investigations on the reaction behavior on a multicomponent bismuth-molybdate oxide catalyst. The reaction temperature showed only small influence on the selectivity to acrolein, but a significant optimum at about 360 °C is observed. The results further indicate a change in the rate-determining step: while at low temperatures (<360 °C) catalyst reoxidation is rate determining, with increasing oxygen content accelerating the formation of acrolein considerably, its influence disappears at higher temperatures. Not only does water increase the selectivity to acrolein, but also, at low temperatures, it improves catalyst reoxidation remarkably. Additionally, the formation of the most important side products (acrylic acid, carbon oxides, acetaldehyde, formaldehyde, and acetic acid) was observed, depending on the reaction parameters.