Multi-scale modeling of fixed-bed Fischer Tropsch reactor

Ghouri, Minhaj; Afzal, Shaik; Hussain, Rehan; Blank, Jan; Bukur, Dragomir B.; Elbashir, Nimir O.

doi:10.1016/j.compchemeng.2016.03.035

Cited by 24 publications

(18 citation statements)

References 25 publications

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“…This outcome describes the FT distribution, which is depicted in Figure 4 and mentioned earlier. Methane activation energy, E Meth , is of 89.9 kJ/mol-very close to outcomes obtained by Bhatelia et al [24] 82.4 kJ/mol, Todic et al [39] 63.0 kJ/mol, and Ghouri et al [61] 83.6. The activation energy for ethylene, E Eth , corresponds to 112.8 kJ/mol, in the middle of the reported value of 125.3 of Moazami et al [21] and 103.2 of Todic et al [17].…”

Section: Ft Kinetic Modelsupporting

confidence: 85%

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Kinetic Study Based on the Carbide Mechanism of a Co-Pt/γ-Al2O3 Fischer–Tropsch Catalyst Tested in a Laboratory-Scale Tubular Reactor

et al. 2019

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A Co-Pt/γ-Al2O3 catalyst was manufactured and tested for Fischer–Tropsch applications. Catalyst kinetic experiments were performed using a tubular fixed-bed reactor system. The operative conditions were varied between 478 and 503 K, 15 and 30 bar, H2/CO molar ratio 1.06 and 2.11 at a carbon monoxide conversion level of about 10%. Several kinetic models were derived, and a carbide mechanism model was chosen, taking into account an increasing value of termination energy for α-olefins with increasing carbon numbers. In order to assess catalyst suitability for the determination of reaction kinetics and comparability to similar Fischer–Tropsch Synthesis (FTS) applications, the catalyst was characterized with gas sorption analysis, temperature-programmed reduction (TPR), and X-ray diffraction (XRD) techniques. The kinetic model developed is capable of describing the intrinsic behavior of the catalyst correctly. It accounts for the main deviations from the typical Anderson-Schulz-Flory distribution for Fischer–Tropsch products, with calculated activation energies and adsorption enthalpies in line with values available from the literature. The model suitably predicts the formation rates of methane and ethylene, as well as of the other α-olefins. Furthermore, it properly estimates high molecular weight n-paraffin formation up to carbon number C80.

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Section: Ft Kinetic Modelsupporting

confidence: 85%

“…The reason for this higher MARR value could be linked to the experimental data scattering found in the FTS distributions. In a recent study on a Co/Al 2 O 3 catalyst, Ghouri et al [61] estimated a MARR value of 48.4%. They attributed this behavior to their small amount of experimental observations.…”

Section: Ft Kinetic Modelmentioning

confidence: 99%

Kinetic Study Based on the Carbide Mechanism of a Co-Pt/γ-Al2O3 Fischer–Tropsch Catalyst Tested in a Laboratory-Scale Tubular Reactor

et al. 2019

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“…The reaction enthalpy (− ∆H rxn ) is an important parameter that determines the amount of heat released during the FT reaction. Previous modeling studies reported values of (−∆H rxn ) ranging from 150 kJ/mol to 165 kJ/mol to represent the FT reaction enthalpy [9,21,30,40,41]. Its value mainly depends on the hydrocarbon product selectivity.…”

Section: Heat Transport Expressionsmentioning

confidence: 99%

Thermal Assessment of a Micro Fibrous Fischer Tropsch Fixed Bed Reactor Using Computational Fluid Dynamics

et al. 2020

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A two-dimensional (2D) Computational Fluid Dynamics (CFD) scale-up model of the Fischer Tropsch reactor was developed to thermally compare the Microfibrous-Entrapped-Cobalt-Catalyst (MFECC) and the conventional Packed Bed Reactor (PBR). The model implements an advanced predictive detailed kinetic model to study the effect of a thermal runaway on C5+ hydrocarbon product selectivity. Results demonstrate the superior capability of the MFECC bed in mitigating hotspot formation due to its ultra-high thermal conductivity. Furthermore, a process intensification study for radial scale-up of the reactor bed from 15 mm internal diameter (ID) to 102 mm ID demonstrated that large tube diameters in PBR lead to temperature runaway >200 K corresponding to >90% CO conversion at 100% methane selectivity, which is highly undesirable. While the MFECC bed hotspot temperature corresponded to <10 K at >30% CO conversion, attributing to significantly high thermal conductivity of the MFECC bed. Moreover, a noticeable improvement in C5+ hydrocarbon selectivity >70% was observed in the MFECC bed in contrast to a significantly low number for the PBR (<5%).

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“…Several one-dimensional (1-D) (or axial) models for FTS reactor beds with conventional catalysts have been reported in the literature for addressing design challenges like scale-up and thermal management for a fixed-bed configuration. 29,[35][36][37][38][39][40][41][42] The primary drawback of such models is the inability to account for radial heat-transfer limitations, leading to potential under estimation of local hot spot magnitude. The twodimensional (2-D) modeling efforts similar to very recent studies by Stamenić et al 43 and Mandić et al, 44 help in determining the transport effects (viz.…”

Section: Introductionmentioning

confidence: 99%

Multidimensional modeling of a microfibrous entrapped cobalt catalyst Fischer‐Tropsch reactor bed

et al. 2017

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Thermal management of highly exothermic Fischer-Tropsch synthesis (FTS) has been a challenging bottleneck limiting the radial dimension of the packed-bed (PB) reactor tube to 1.5 in. ID. A computational demonstration of a novel microfibrous entrapped cobalt catalyst (MFECC) in mitigating hot spot formation has been evaluated. Specifically, a two-dimensional (2-D) model was developed in COMSOL V R , validated with experimental data and subsequently employed to demonstrate scale-up of the FTS bed from 0.59 to 4 in. ID. Significant hot spot of 102.39 K in PB was reduced to 9.4 K in MFECC bed under gas phase at 528.15 K and 2 MPa. Improvement in heat transfer within the MFECC bed facilitates higher productivities at low space velocities (!1000 h 21) corresponding to high CO conversion (!90%). Additionally, the MFECC reactor provides an eightfold increase in the reactor ID at hot spots 30 K with CO% conversions ! 90%. This model was developed for a typical FTS cobalt-based catalyst where CO 2 production is negligible.

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Multi-scale modeling of fixed-bed Fischer Tropsch reactor

Cited by 24 publications

References 25 publications

Kinetic Study Based on the Carbide Mechanism of a Co-Pt/γ-Al2O3 Fischer–Tropsch Catalyst Tested in a Laboratory-Scale Tubular Reactor

Kinetic Study Based on the Carbide Mechanism of a Co-Pt/γ-Al2O3 Fischer–Tropsch Catalyst Tested in a Laboratory-Scale Tubular Reactor

Thermal Assessment of a Micro Fibrous Fischer Tropsch Fixed Bed Reactor Using Computational Fluid Dynamics

Multidimensional modeling of a microfibrous entrapped cobalt catalyst Fischer‐Tropsch reactor bed

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