High Loading Fe-supported Fischer–Tropsch Catalysts: Optimization of the Catalyst Performance

Pirola, Carlo; Bianchi, Claudia L.; Michele, Alessandro Di; Diodati, P.; Vitali, S.; Ragaini, V.

doi:10.1007/s10562-009-0060-6

Cited by 19 publications

(23 citation statements)

References 29 publications

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“…With cobalt, a correlation between the presence of Co 2 C and a high selectivity to methane has been reported [15]. On iron-based catalysts, studies report a fast and reversible exchange of Fe 3 O 4 into Fe x C carbides and vice versa depending upon reaction environment, as a consequence of elementary FTS steps [16,17], whereas the activity can be correlated with the iron carbide surface area [18]. The facile transformation of the catalytic phases makes it likely that carbon atoms in the surface become incorporated into reaction products [19], in a way that is similar as in oxidation catalysis, where the Mars-van Krevelen mechanism is commonly invoked [20].…”

Section: Introductionmentioning

confidence: 98%

Mars-van Krevelen-like Mechanism of CO Hydrogenation on an Iron Carbide Surface

2009

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Computational chemistry is used to explore a mechanism for CO hydrogenation to methane on iron carbides. As CO dissociation is endothermic on carbon terminated Fe 5 C 2 (100) cuts, we explore a path starting with the hydrogenation of the surface, which liberates iron 4-fold sites for adsorption and dissociation of CO. The reaction cycle to methane resembles the Mars-van Krevelen mechanism for oxidation reactions.

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Section: Introductionmentioning

confidence: 98%

Mars-van Krevelen-like Mechanism of CO Hydrogenation on an Iron Carbide Surface

2009

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“…A comparison of data shows that the introduction of iron, potassium, and copper into SiO 2 reduces the surface area from 305 to 133 m 2 · g −1 without a significant change of the micropore percentage. This reduction in surface area may be due to the diluting effect of the metals …”

Section: Resultsmentioning

confidence: 99%

“…The probability of chain growth remains steady in the range 250–260 °C and 1 < H 2 /CO < 2. The temperature range considered was limited because this parameter was already optimized for this kind of catalyst in our previous work …”

Section: Resultsmentioning

confidence: 99%

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High‐loaded Fe‐supported catalyst for the thermochemical BtL‐FT process: Experimental results and modelling

et al. 2015

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Bio-syngas, i.e. the syngas mixture produced from biomass, is mainly characterized from a H 2 /CO molar ratio in the range 1.0-1.5, different from those of traditional syngas equal to 2. By feeding directly this mixture in a catalytic reactor for Fischer-Tropsch synthesis, iron based catalysts are more suitable with respect to the cobalt-based one. These catalysts are used industrially in their massive form. The possibility to use supported Fe-based catalysts are recently deeply considered in order to improve the surface area and the mechanical stability of the samples. In particular high Fe loaded supported catalysts are required to achieve satisfactory performance. Iron-based catalysts supported on silica for CO hydrogenation with 30%wt of metal have been prepared, characterized by BET, SEM, TEM, TPR, XRD and tested at different temperature and H 2 /CO ratio in a FT laboratory plant using a Packed Bed Reactor. On the basis of the collected data, a multi-scale simulation of the FT synthesis reactor has been developed considering that on the catalyst surface the reaction both of FT and Water Gas Shift are simultaneously activated. The experimental results demonstrated that by increasing the inlet H 2 /CO ratio, the CO conversion can be increased while preserving the products selectivity and confirm that FT are suitable also for low H 2 /CO ratio; furthermore the model elaborated agree with the experimental data obtained.

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“…The activation step is critical for several processes to produce a selective catalyst like for Fischer‐Tropsch synthesis . Scientists and engineers study the role of preparation procedure (time, temperature, and hydrogen partial pressure, for example), promoters, dopants, and stabilizing agents to enhance catalyst stability, activity, and yield.…”

Section: Introductionmentioning

confidence: 99%

Experimental methods in chemical engineering: Temperature programmed reduction—TPR

2018

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Temperature programmed reduction (TPR) characterizes the oxido‐reduction properties of bulk and supported catalysts. H2 or CO passes over a pre‐conditioned solid sample as a furnace ramps the temperature at a constant rate. A thermal conductivity detector (TCD) or mass spectrometer records the effluent concentration. In the pre‐conditioning step, Ar or He flushes residual air and absorbed water from the solid sample to maximize the signal‐to‐noise ratio of the TCD signal. We calculate the number of active sites based on the detector signal that correlates with how much hydrogen reacts. The temperature at which it begins to react represents the minimum activation temperature. TPR is cheap, fast, easy to run, and the data is straightforward to interpret. The technique is more popular with chemical engineers than with the broader scientific community. Among the 27 articles that Can. J. Chem. Eng. published in 2016 and 2017 that apply TPR to analyze catalysts, 22 mention reactors, 20 report XRD spectra, 18 mention gas chromatography, and another 15 quantify surface area by BET. Synergy with other temperature programmed methods is lower, as only 5 mention temperature programmed desorption, 5 thermal gravimetric analysis, and 3 temperature programmed oxidation.

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High Loading Fe-supported Fischer–Tropsch Catalysts: Optimization of the Catalyst Performance

Cited by 19 publications

References 29 publications

Mars-van Krevelen-like Mechanism of CO Hydrogenation on an Iron Carbide Surface

Mars-van Krevelen-like Mechanism of CO Hydrogenation on an Iron Carbide Surface

High‐loaded Fe‐supported catalyst for the thermochemical BtL‐FT process: Experimental results and modelling

Experimental methods in chemical engineering: Temperature programmed reduction—TPR

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