Mesoporous Fe-based spindles designed as catalysts for the Fischer–Tropsch synthesis of C5+ hydrocarbons

2018 ◽  
Vol 42 (19) ◽  
pp. 15968-15973 ◽  
Author(s):  
Yulan Zhang ◽  
Xizhu Lin ◽  
Xinjun Li ◽  
Chenguang Wang ◽  
Qiong Long ◽  
...  
Keyword(s):  
Active Phase ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Unique Structure ◽  
Metal Support ◽  
Metal Support Interactions

Novel active phase assembled mesoporous spindles are designed. This unique structure avoids metal-support interactions and displays high C5+ selectivity.

Metal-support interactions regulated via carbon coating – A case study of Co/SiO2 for Fischer-Tropsch synthesis

Fuel ◽  
2018 ◽  
Vol 226 ◽  
pp. 213-220 ◽  
Author(s):  
Zhong-Shan Jiang ◽  
Yong-Hua Zhao ◽  
Chuan-Feng Huang ◽  
Yong-Hong Song ◽  
Da-Peng Li ◽  
...  
Keyword(s):  
Carbon Coating ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Metal Support ◽  
Metal Support Interactions

Tuning catalytic performance in Fischer-Tropsch synthesis by metal-support interactions

2020 ◽  
Author(s):  
Lebohang Macheli ◽  
Emanuela Carleschi ◽  
Bryan P. Doyle ◽  
Gerard Leteba ◽  
Eric van Steen
Keyword(s):  
Catalytic Performance ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Metal Support ◽  
Metal Support Interactions

Isomorphic titanium-substituted mesoporous SBA-16 as support for cobalt Fischer–Tropsch synthesis catalysts: Balance between dispersion and reduction

2021 ◽  
Author(s):  
Liang Wei ◽  
Jian Chen ◽  
Shuai Lyu ◽  
Chengchao Liu ◽  
Yanxi Zhao ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Support Interaction ◽  
Delicate Balance ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Synthesis Catalysts

The delicate balance between dispersion and reduction of the Co-based Fischer–Tropsch synthesis catalyst is the golden key to enhancing catalytic performance, which highly depends on an optimized metal–support interaction. In...

Size dependent stability of cobalt nanoparticles on silica under high conversion Fischer–Tropsch environment

2017 ◽  
Vol 197 ◽  
pp. 243-268 ◽  
Author(s):  
Moritz Wolf ◽  
Hendrik Kotzé ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Type Species ◽  
Tropsch Synthesis ◽  
High Conversion ◽  
Metallic Surface ◽  
Metallic State ◽  
Direct Oxidation ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Metal Support ◽  
Presence And Absence

Highly monodisperse cobalt crystallites, supported on Stöber silica spheres, as model catalysts for the Fischer–Tropsch synthesis were exposed to simulated high conversion environments in the presence and absence of CO utilising an in house developedin situmagnetometer. The catalyst comprising the smallest crystallites in the metallic state (average diameter of 3.2 nm) experienced pronounced oxidation whilst the ratio of H2O to H2was increased stepwise to simulate CO conversions from 26% up to complete conversion. Direct exposure of this freshly reduced catalyst to a high conversion Fischer–Tropsch environment resulted in almost spontaneous oxidation of 40% of the metallic cobalt. In contrast, a model catalyst with cobalt crystallites of 5.3 nm only oxidised to a small extent even when exposed to a simulated conversion of over 99%. The largest cobalt crystallites were rather stable and only experienced measurable oxidation when subjected to H2O in the absence of H2. This size dependency of the stability is in qualitative accordance with reported thermodynamic calculations. However, the cobalt crystallites showed an unexpected low susceptibility to oxidation,i.e.only relatively high ratios of H2O to H2partial pressure caused oxidation. Similar experiments in the presence of CO revealed the significance of the actual Fischer–Tropsch synthesis on the metallic surface as the dissociation of CO, an elementary step in the Fischer–Tropsch mechanism, was shown to be a prerequisite for oxidation. Direct oxidation of cobalt to CoO by H2O seems to be kinetically hindered. Thus, H2O may only be capable of indirect oxidation,i.e.high concentrations prevent the removal of adsorbed oxygen species on the cobalt surface leading to oxidation. However, a spontaneous direct oxidation of cobalt at the interface between the support and the crystallites by H2O forming presumably cobalt silicate type species was observed in the presence and absence of CO. The formation of these metal–support compounds is in accordance with conducted thermodynamic predictions. None of the extreme Fischer–Tropsch conditions initiated hydrothermal sintering. Seemingly, the formation of metal–support compounds stabilised the metallic crystallites and/or higher partial pressures of CO are required to increase the concentration of mobile, cobalt oxide-type species on the metallic surface.

scholarly journals Significance of C3 Olefin to Paraffin Ratio in Cobalt Fischer–Tropsch Synthesis

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 967
Author(s):  
Erling Rytter ◽  
Jia Yang ◽  
Øyvind Borg ◽  
Anders Holmen
Keyword(s):  
Residence Time ◽  
Tropsch Synthesis ◽  
Cobalt Catalysts ◽  
Feed Ratio ◽  
Water Addition ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Added Water

The ratio between propene and propane (C3 o/p) during Fischer–Tropsch synthesis (FTS) has been analyzed based on both literature reports and experiments for five catalysts. The latter comprise four cobalt catalysts on γ-alumina with variations in pore sizes, and one catalyst on α-alumina. Overall variations include H2/CO feed ratio, residence time, water addition, transients between test conditions, CO conversion, cobalt particle size, promoter (Re), and support material. It was possible to rationalize all data based on secondary hydrogenation of olefins. In fact, it was deduced that olefins are dominating termination products in FTS, estimated to ca. 90% for C3, but that some paraffins most likely are also produced directly. Increased residence time and high H2/CO feed ratio favors olefin hydrogenation, while added water presumably displaces hydrogen on cobalt giving enhanced C3 o/p. High cobalt dispersion favors hydrogenation, as also promoted by Re. Effect of intraparticle diffusion is seen in transient periods; for example, as water is added or depleted. There is frequently positive correlation between C3 o/p and selectivity to longer chains; the latter expressed as C5+ selectivity, as both are sensitive to hydrogen activity. Some modifications, however, are needed due to the accepted volcano plot for C5+ selectivity with cobalt crystallite size. Titania as support shows unexpectedly low C3 o/p; probably due to SMSI (strong-metal-support-interaction).

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