Mathematical modeling of internal mass transport limitations in methanol synthesis

Lommerts, Bert Jan; Graaf, G.H.; Beenackers, A.A.C.M.

doi:10.1016/s0009-2509(00)00194-9

Cited by 78 publications

(56 citation statements)

References 13 publications

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“…In the dusty gas model which is based on StefanMaxwell equations, both diffusional and convective mass transport terms are considered, and this includes the description of pressure drop over the catalyst particle resulting from the stoichiometry of reaction and accompanying convective transport of molecules [51].…”

Section: Appendix A: Dusty Gas Modelmentioning

confidence: 99%

A comparison of hydrogen and methanol production in a thermally coupled membrane reactor for co-current and counter-current flows

Rahimpour

Pourazadi

2010

Int. J. Energy Res.

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SUMMARYThis work considers three concentric tube reactors to prepare pure hydrogen, especially applicable in fuel cell technologies, with zero CO 2 emission. Hydrogen and methanol production rates are compared in a thermally coupled exothermic and endothermic reactor for co-current and counter-current modes. Synthesis of methanol is coupled with dehydrogenation of cyclohexane as a high content hydrogen carrier (7.1 wt%). The efficient coupling of exothermic and endothermic reactions increases the profitability of operation of the reactor, reduces the size of reactor and decreases the operational and capital costs. By inserting a hydrogen-perm selective membrane into the reactor configuration, hydrogen can permeate selectively into the membrane, and hence, the third tube receives hydrogen. The simulation results are compared with the corresponded results for an industrial methanol fixed-bed reactor, which operates under the same feed conditions. The influence of some operating variables is investigated on methanol and hydrogen yields during the performance of reactor. The results show higher methanol conversion, as the same as conventional reactor, and hydrogen for co-current flow.

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Section: Appendix A: Dusty Gas Modelmentioning

confidence: 99%

A comparison of hydrogen and methanol production in a thermally coupled membrane reactor for co-current and counter-current flows

Rahimpour

Pourazadi

2010

Int. J. Energy Res.

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“…Effectiveness factors are calculated using the dusty gas model [25,26], in which the mixed diffusion (D e m, i ) is determined as follows:…”

Section: Reactor Modelmentioning

confidence: 99%

“…refer to Lommerts et al [25]), the Thiele modulus is determined as follows: (23) Finally, the effectiveness factor is calculated by using the following equation [28]:…”

Section: Reactor Modelmentioning

confidence: 99%

Optimization of methanol synthesis reaction on Cu/ZnO/Al2O3/ZrO2 catalyst using genetic algorithm: Maximization of the synergetic effect by the optimal CO2 fraction

Lim

Jun

Park

et al. 2010

Korean J. Chem. Eng.

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A kinetics model that takes the synergetic effect of carbon dioxide fraction on the methanol production rate into account is applied to the development of a mathematical model for the bench-scale reactor. A comparison between the simulation results and the experimental data corroborates the validity of the model. Several optimization strategies are suggested to maximize the methanol yield, among which the utilization of piecewise trajectories for wall temperature along the reactor axis as well as the optimal CO 2 fraction at the inlet of the reactor is found to be the best strategy in the sense of methanol production per unit amount of the feed, in such a way that the optimization strategy considers the variation of the reaction temperature in the reactor and maximizes the synergetic effect on the production rate by the addition of carbon dioxide.

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“…It is said that commercial size CuO/ZnO/Al 2 O 3 catalysts exhibit intra-particle diffusion limitations [8], so in the modeling of an industrial methanol synthesis process internal mass transport limitation should be taken into account [15]. The dusty gas model is widely used to describe intra-particle diffusion limitations in methanol synthesis over commercial CuO/ZnO/Al 2 O 3 catalysts.…”

Section: Appendix B: Dusty Gas Modelmentioning

confidence: 99%

“…In the dusty gas model, which is based on the Stefan-Maxwell equations, both diffusional and convective mass transport terms are considered, and this includes the description of pressure drop over the catalyst particle resulting from the stoichiometry of the reaction and accompanying convective transport of molecules [15]. The results of sensitivity analyses show that at low pressures (up to 10 bar), Knudsen diffusion is the most important diffusing term, while at high pressures (100 bar) bulk diffusion predominates [8].…”

Section: Appendix B: Dusty Gas Modelmentioning

confidence: 99%

Operability of an Industrial Methanol Synthesis Reactor with Mixtures of Fresh and Partially Deactivated Catalyst

Rahimpour

Moghtaderi

Jahanmiri

et al. 2005

Chem. Eng. Technol.

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Disposal of spent catalyst is a common practice in industrial methanol synthesis. However, the spent catalyst has, generally, a good level of activity and can be used if mixed with fresh catalyst. In this work the operation of an industrial methanol synthesis reactor with mixtures of fresh and partially deactivated catalyst was investigated using a one-dimensional transient model. Analysis of the deactivation behavior of low-pressure methanol synthesis catalyst shows there is an extremely sharp rate of deactivation in a small part of the catalyst life-time, which is followed by a relatively slow rate of deactivation in the remaining catalyst cycle-time. Different configurations were studied for catalyst recycling, and two limiting cases are discussed in detail in this paper, namely layered and homogeneous (mixed) bed models. In the first one, the catalyst was segregated into two alternate layers of fresh and partially deactivated catalyst, while in the second homogeneity of the catalyst bed was simulated by segregating a large number of alternate layers of fresh and partially deactivated catalyst. It was observed in both cases that when catalyst recycling is used, the process does not depart significantly from the standard operating conditions, and also that the mixed bed had less influence on the reactor performance than layered one.

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Mathematical modeling of internal mass transport limitations in methanol synthesis

Cited by 78 publications

References 13 publications

A comparison of hydrogen and methanol production in a thermally coupled membrane reactor for co-current and counter-current flows

A comparison of hydrogen and methanol production in a thermally coupled membrane reactor for co-current and counter-current flows

Optimization of methanol synthesis reaction on Cu/ZnO/Al2O3/ZrO2 catalyst using genetic algorithm: Maximization of the synergetic effect by the optimal CO2 fraction

Operability of an Industrial Methanol Synthesis Reactor with Mixtures of Fresh and Partially Deactivated Catalyst

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