Effect of activation atmosphere in the Fischer–Tropsch Synthesis using a “quasi-model” catalyst of γ-Fe2O3 nanoparticles supported on SBA-15

Berti, Ignacio O. Pérez De; Bengoa, J. F.; Stewart, S. J.; Cagnoli, M. V.; Pecchi, Gina; Marchetti, Sérgio Gustavo

doi:10.1016/j.jcat.2015.12.004

Cited by 15 publications

(5 citation statements)

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“…Research suggests that the iron carbides favor the formation of methane [16,17]. This prediction is supported based on the calculated reaction energies and effective barriers by [16] using spin-polarized density functional theory calculations that CH 4 formation is more favorable on Fe 5 C 2 and Fe 2 C. The XRD analysis of spent catalyst seen in Fig.…”

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confidence: 72%

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

et al. 2018

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Laboratory experiments conducted for long time on stream (TOS: 14,350 h) provide information on Fischer-Tropsch synthesis (FTS) that is representative of time scales of industrial operations. Operation conditions that deliver desirable conversion and product distribution were investigated. Low gas hourly space velocity (GHSV) gave the highest conversion of 20.97% with the highest C 5+ selectivity achieved was 59.77%, which was obtained at the highest GHSV level. A one-way ANOVA, followed by a post-hoc Bonferroni correction test, indicated a significant difference in response to GHSV with P(T <=t) two-tail values ranging from 1.5 × 10 −4 to 2.7 × 10 −35. The optimum condition for paraffin production is high pressure and low GHSV: in our experiments, this corresponded to 20.85 bar (abs): 648 h −1. Conversely, olefins production is favored low pressure and low GHSV [1.85 bar (abs): 648 h −1 ]. C 5+ production was favored at high GHSV (2592 h −1) and was very sensitive to GHSV, as the sensitivity to C 5+ products dropped sharply when the GHSV decreased to low values (from 1296 to 648 h −1); furthermore, the selectivity to C 5+ was found to be independent of pressure. The pressure effect on selectivity is complex and selectivity toward overall gaseous (paraffin + olefin) hydrocarbons and C 5+ does not seem to be significantly affected by variations in pressure. Long TOS FTS runs are possible ca. 14,500 h though product distribution trends tend to be changed. The catalyst survived long runs, though the selectivity to FTS became comparatively less favored than WGS with increasing TOS. Our findings may have useful implication for the design of a mobile small-scale biomass/waste to liquid process that would last for period similar to that of an industrial plant.

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confidence: 72%

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

et al. 2018

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“…Surprisingly, FeSi-H 2 catalyst presents the lowest CH 4 selectivity (10.6%) and highest C 5+ selectivity (74.4%), which is extraordinary among promoter-free Fe/SiO 2 catalysts. For example, Suo et al 33 reported 15.6% CH 4 selectivity in an Fe/ SiO 2 catalyst mainly containing χ-Fe 5 C 2 carbide using 2H 2 /CO treatment; Peŕez De Berti et al 39 reported ∼18 or ∼31% CH 4 selectivity on Fe/SBA-15 catalyst containing 22 or 14% carbides (χ-Fe 5 C 2 + ε-Fe 2.2 C). In addition, the prolonged reduction time increases the FTY due to the increased active phase content, while the variation of space velocity does not change the FTY value.…”

Section: Resultsmentioning

confidence: 99%

“…In earlier work from our group, 33 the effect of size on selectivity was observed: the CH 4 selectivity gradually decreased and C 5+ gradually increased with decreasing particle size. Peŕez De Berti et al 39 considered that more facets could be exposed when the particle size was small, and some of the emerging facets with a specific configuration could favor chain growth. The de Jong group 61 studied the size effect in Fischer− Tropsch to lower olefins at 340−350 °C, H 2 /CO = 1, and pressures of 1 and 20 bar.…”

Section: Relationship Between Activementioning

confidence: 99%

Relationship between Iron Carbide Phases (ε-Fe₂C, Fe₇C₃, and χ-Fe₅C₂) and Catalytic Performances of Fe/SiO₂ Fischer–Tropsch Catalysts

et al. 2018

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The influence of different iron carbides on the activity and selectivity of iron-based Fischer−Tropsch catalysts has been studied. Different iron carbide phases are obtained by the pretreatment of a binary Fe/SiO 2 model catalyst (prepared by coprecipitation method) to different gas atmospheres (syngas, CO, or H 2 ). The phase structures, compositions, and particle sizes of the catalysts are characterized systematically by XRD, XAFS, MES, and TEM. It is found that in the syngas-treated catalyst only χ-Fe 5 C 2 carbide is formed. In the CO-treated catalyst, Fe 7 C 3 and χ-Fe 5 C 2 with a bimodal particle size distribution are formed, while the H 2 -treated catalyst exhibits the bimodal size distributed ε-Fe 2 C and χ-Fe 5 C 2 after a Fischer−Tropsch synthesis (FTS) reaction. The intrinsic FTS activity is calculated and assigned to each corresponding iron carbide based on the phase composition and the particle size. It is identified that Fe 7 C 3 has the highest intrinsic activity (TOF = 4.59 × 10 −2 s −1 ) among the three candidate carbides (ε-Fe 2 C, Fe 7 C 3 , and χ-Fe 5 C 2 ) in typical medium-temperature Fischer−Tropsch (MTFT) conditions (260−300 °C, 2−3 MPa, and H 2 /CO = 2). Moreover, FTS over ε-Fe 2 C leads to the lowest methane selectivity.

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“…To prepare iron-based catalysts with a narrow particle-size distribution, SBA-15 and KIT-6 as suitable mesoporous supports have often been used in FTS [191,201]. SBA-15 has a narrow pore-size distribution and thermal stability.…”

Section: Supports In Ftsmentioning

confidence: 99%

Recent advances in application of iron-based catalysts for CO hydrogenation to value-added hydrocarbons

Liu

Song

Guo

et al. 2022

Chinese Journal of Catalysis

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Effect of activation atmosphere in the Fischer–Tropsch Synthesis using a “quasi-model” catalyst of γ-Fe2O3 nanoparticles supported on SBA-15

Cited by 15 publications

References 50 publications

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

Relationship between Iron Carbide Phases (ε-Fe₂C, Fe₇C₃, and χ-Fe₅C₂) and Catalytic Performances of Fe/SiO₂ Fischer–Tropsch Catalysts

Recent advances in application of iron-based catalysts for CO hydrogenation to value-added hydrocarbons

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Effect of activation atmosphere in the Fischer–Tropsch Synthesis using a “quasi-model” catalyst of γ-Fe2O3 nanoparticles supported on SBA-15

Cited by 15 publications

References 50 publications

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

Fischer–Tropsch synthesis: product distribution, operating conditions, iron catalyst deactivation and catalyst speciation

Relationship between Iron Carbide Phases (ε-Fe2C, Fe7C3, and χ-Fe5C2) and Catalytic Performances of Fe/SiO2 Fischer–Tropsch Catalysts

Recent advances in application of iron-based catalysts for CO hydrogenation to value-added hydrocarbons

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Relationship between Iron Carbide Phases (ε-Fe₂C, Fe₇C₃, and χ-Fe₅C₂) and Catalytic Performances of Fe/SiO₂ Fischer–Tropsch Catalysts