Application of Anderson–Schulz–Flory (ASF) equation in the product distribution of slurry phase FT synthesis with nanosized iron catalysts

Tavakoli, Akram; Sohrabi, Morteza; Kargari, Ali

doi:10.1016/j.cej.2007.04.017

Cited by 73 publications

(53 citation statements)

References 14 publications

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“…The product distribution from the Fischer-Tropsch synthesis as a function of chain growth probability in molar fraction and mass fraction are depicted in Figure 6 [64]. It can be predicted from the ASF distribution that the maximum selectivity to gasoline range (C5-C11) and diesel range (C12-C20) hydrocarbons are around 45% and 30%, respectively [65]. Figure 6.…”

Section: Fischer-tropsch Synthesismentioning

confidence: 99%

Application of Fischer–Tropsch Synthesis in Biomass to Liquid Conversion

2012

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Fischer-Tropsch synthesis is a set of catalytic processes that can be used to produce fuels and chemicals from synthesis gas (mixture of CO and H 2 ), which can be derived from natural gas, coal, or biomass. Biomass to Liquid via Fischer-Tropsch (BTL-FT) synthesis is gaining increasing interests from academia and industry because of its ability to produce carbon neutral and environmentally friendly clean fuels; such kinds of fuels can help to meet the globally increasing energy demand and to meet the stricter environmental regulations in the future. In the BTL-FT process, biomass, such as woodchips and straw stalk, is firstly converted into biomass-derived syngas (bio-syngas) by gasification. Then, a cleaning process is applied to remove impurities from the bio-syngas to produce clean bio-syngas which meets the Fischer-Tropsch synthesis requirements. Cleaned bio-syngas is then conducted into a Fischer-Tropsch catalytic reactor to produce green gasoline, diesel and other clean biofuels. This review will analyze the three main steps of BTL-FT process, and discuss the issues related to biomass gasification, bio-syngas cleaning methods and conversion of bio-syngas into liquid hydrocarbons via Fischer-Tropsch synthesis. Some features in regard to increasing carbon utilization, enhancing catalyst activity, maximizing selectivity and avoiding catalyst deactivation in bio-syngas conversion process are also discussed.

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Section: Fischer-tropsch Synthesismentioning

confidence: 99%

Application of Fischer–Tropsch Synthesis in Biomass to Liquid Conversion

2012

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“…The non-polar Fe-carbide surface seems to be responsible for the production of paraffins and olefins, while the polar Fe-oxide surface could be responsible for the production of light hydrocarbons, olefins and oxygenates [48]. The deviation from the ASF distribution has been noted particularly for its poor suitability for nanometric catalytic systems, and this could be an indicator of critical variations in the dominant growth mechanisms of FTS catalyzed by nanoparticles [49]. Since the predicted α-values for the Co catalyst by the ASF model is in the range of 0.70-0.80, our Co/C catalyst depending on reaction conditions was found to be greater, in the range of 0.78-0.87 (for H 2 :CO = 2), and 0.93 (for H 2 :CO ≤ 1.5).…”

Section: Catalyst Selectivity and α-Valuesmentioning

confidence: 99%

Effect of CO Concentration on the α-Value of Plasma-Synthesized Co/C Catalyst in Fischer-Tropsch Synthesis

Aluha

Abatzoglou

2017

Catalysts

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Abstract:A plasma-synthesized cobalt catalyst supported on carbon (Co/C) was tested for Fischer-Tropsch synthesis (FTS) in a 3-phase continuously-stirred tank slurry reactor (3-φ-CSTSR) operated isothermally at 220 • C (493 K), and 2 MPa pressure. Initial syngas feed stream of H 2 :CO ratio = 2 with molar composition of 0.6 L/L (60 vol %) H 2 and 0.3 L/L (30 vol %) CO, balanced in 0.1 L/L (10 vol %) Ar was used, flowing at hourly space velocity (GHSV) of 3600 cm 3 ·h −1 ·g −1 of catalyst. Similarly, other syngas feed compositions of H 2 :CO ratio = 1.5 and 1.0 were used. Results showed~40% CO conversion with early catalyst selectivity inclined towards formation of gasoline (C 4 -C 12 ) and diesel (C 13 -C 20 ) fractions. With prolonged time-on-stream (TOS), catalyst selectivity escalated towards the heavier molecular-weight fractions such as waxes (C 21+ ). The catalyst's α-value, which signifies the probability of the hydrocarbon-chain growth was empirically determined to be in the range of 0.85-0.87 (at H 2 :CO ratio = 2), demonstrating prevalence of the hydrocarbon-chain propagation, with particular predisposition for wax production. The inhibiting CO effect towards FTS was noted at molar H 2 :CO ratio of 1.0 and 1.5, giving only~10% and~20% CO conversion respectively, although with a high α-value of 0.93 in both cases, which showed predominant production of the heavier molecular weight fractions.

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“…This is because the values of k p and k d are independtent of n, which means the same reactivity of PODE n compounds independent of molecular size during the chain propagation. Using statistical method (Flory, 1940;Kissin, 1995;Schulz, 1999;Tavakoli et al, 2008), the same reactivity of PODE n compounds lead to transient molecular size distribution model the same expression with Eq. (6), accounting for the applicability of the molecualr size distribution model at transient state.…”

Section: Reactions and Product Molecular Size Distributionmentioning

confidence: 94%