Effect of catalyst preparation conditions on the performance of eggshell cobalt/SiO2 catalysts for Fischer–Tropsch synthesis

Gardezi, Syed Ali; Wolan, John T.; Joseph, Babu

doi:10.1016/j.apcata.2012.09.035

Cited by 22 publications

(30 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gaderzi et al [63] examined the effect of calcination conditions on the performance of a cobalt/silica catalyst and also considered the metal crystallites distribution affected by solvent, during catalyst preparation via solution impregnation; they achieved higher active surface area and better dispersed metal, in the case of alcohol as a primary solvent compared to water. Song et al [64] considered the effect of support pore size on catalyst characterization and its activity in the F-T hydrogenation process; and concluded higher activity and productivity for the catalyst with pore sizes ranging 6-10 nm.…”

Section: Catalyst Carrier Materialsmentioning

confidence: 99%

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Mahmoudi

Doustdar

et al. 2017

Biofuels Engineering

155

View full text Add to dashboard Cite

For more than half a century, Fischer-Tropsch synthesis (FTS) of liquid hydrocarbons was a technology of great potential for the indirect liquefaction of solid or gaseous carbon-based energy sources (Coal-To-Liquid (CTL) and Gas-To-Liquid (GTL)) into liquid transportable fuels. In contrast with the past, nowadays transport fuels are mainly produced from crude oil and there is not considerable diversity in their variety. Due to some limitations in the first generation bio-fuels, the Second-Generation Biofuels (SGB)' technology was developed to perform the Biomass-To-Liquid (BTL) process. The BTL is a well-known multi-step process to convert the carbonaceous feedstock (biomass) into liquid fuels via FTS technology. This paper presents a brief history of FTS technology used to convert coal into liquid hydrocarbons; the significance of bioenergy and SGB are discussed as well. The paper covers the characteristics of biomass, which is used as feedstock in the BTL process. Different mechanisms in the FTS process to describe carbon monoxide hydrogenation as well as surface polymerization reaction are discussed widely in this paper. The discussed mechanisms consist of carbide, COinsertion and the hydroxycarbene mechanism. The surface chemistry of silica support is discussed. Silanol functional groups in silicon chemistry are explained extensively. The catalyst formulation in the Fischer Tropsch (F-T) process as well as F-T reaction engineering is discussed. In addition, the most common catalysts are introduced and the current reactor technologies in the F-T indirect liquefaction process are considered. process overview IntroductionThe over-reliance of the world's nations on conventional fossil fuels puts our planet in peril. The continuity of the current situation will result in the rise of a combined average temperature over global land and ocean surfaces by 5 ∘ C in 2100, bringing a rise in sea levels, food and water shortages and an increase in extreme weather events. The global warming, caused by humans, is one of the biggest threats to our future well-being [1]. In addition, oil reserves are limited and these reserves are decreasing dramatically. This reduction alongside the other relevant economic factors affects the world's oil prices. The need to run engines with the new generation of liquid fuels is inevitable. The investigations by the US Energy Information Administration (EIA) published in 2013 expressed a 56 percent increase in the world's energy consumption by the year 2040. Total world energy demand will have risen to 865 EJ (exajoule) by this year. The total world energy consumption was reported as 553 EJ in 2010. The outlook indicates that renewable energy is one of the fastest-growing energy sources in the world; where its usage increases 2.5 percent per year. Despite increasing success in the renewable energies, it is predicted that the fossil fuels will supply al-

show abstract

Section: Catalyst Carrier Materialsmentioning

confidence: 99%

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Mahmoudi

Doustdar

et al. 2017

Biofuels Engineering

155

View full text Add to dashboard Cite

show abstract

“…This is particularly important for reactions where diffusional limitations strongly affect the conversion, when striving to improve the selectivity to a primary product or for high temperature reactions, where proper heat transport in the catalyst layer is required [31]. There is a large number of reactions where the importance of having an egg-shell distribution has already been recognized: Fisher-Tropsch synthesis [40], selective oxidation reactions [31] (e.g. production of acrolein from propene and of phthalic anhydride from o-xylene), volatile organic compounds abatement [41], purification of automobile exhaust gases [42,43], selective hydrogenation of pyrolysis gasoline [44], and autothermal decomposition of liquid hydrocarbons on NiO/ɣ-Al 2 O 3 [45].…”

Section: Introductionmentioning

confidence: 99%

“…Both of these distributions are sought when the catalyst surface is prone to deactivation through poisoning or abrasion mechanisms [38] and for reactions that are negative order in reactant concentration [39]. The egg-shell distribution is characterized by having a thin active phase profile in the outer-shell of the support body [31,40]. This is particularly important for reactions where diffusional limitations strongly affect the conversion, when striving to improve the selectivity to a primary product or for high temperature reactions, where proper heat transport in the catalyst layer is required [31].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

Silva¹,

Nielsen²,

Fiordaliso³

et al. 2015

Applied Catalysis A: General

View full text Add to dashboard Cite

“…at approximately 493 K (ΔT ≈ 20K) 6,14 . Likewise, there are conflicting 4 arguments on whether an eggshell catalyst design improves both the selectivity and activity, however, it 5 is generally accepted that selectivity does improves with egg-shell morphology (as discussed in Section 2) 6 1,9 . Here, we develop a strategy to identify the ideal eggshell thickness for a given set of process 7…”

mentioning

confidence: 96%

“…active material needs to be deposited close to the surface. Prior 38 work by the authors has shown that a slab model is adequate for characterizing thin egg-shell coatings 39 whereas the sphere model is better at for FTS catalysts for a thicker shell 1 . Under a typical fixed bed 1 reactor operation, using cobalt catalyst, the preference towards eggshell design becomes debatable since 2 the operational envelope is very narrow e.g.…”

mentioning

confidence: 98%

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Gardezi

Joseph

2015

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

11In this paper, we investigate the performance characteristics of cobalt catalyst (Co/SiO2) pellets with 12 eggshell morphology used in Fischer-Tropsch synthesis (FTS). An analytical strategy is developed first, to 13 estimate the optimum thickness of active shell. When the system is strongly mass transfer limited (Thiele 14 Modulus≫1) it can be represented by slab geometry in order to determine the shell thickness. Otherwise, 15 the analysis is done on a spherical geometry. In the latter case, the continuity equation simplifies into 16Emden-Fowler equation which was solved via numerical iterative technique based on prior investigations. 17 A more accurate detailed numerical solution was also developed for this intra-pellet model. This numerical 18 result is compared with the analytical solution as well as with a previously published model. The sensitivity 19 of the catalyst performance to temperature and pressure variations was also examined. Performance 20 analysis was carried out considering both rate of reaction and α chain growth probability as yardsticks. 21These performance parameters were examined using contour maps with Thiele modulus and H2/CO ratio 22 as their coordinates. On this map there exists an ideal combination of gas ratio and Thiele modulus that 23 fulfills the design requirements of product selectivity and high catalyst activity. This study confirms the 24 need for, and the advantage of, using egg-shell morphology for Fischer-Tropsch synthesis applications . 25 26 27 28 29 30 31 32 33

show abstract

Effect of catalyst preparation conditions on the performance of eggshell cobalt/SiO2 catalysts for Fischer–Tropsch synthesis

Cited by 22 publications

References 68 publications

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study

Contact Info

Product

Resources

About

Effect of catalyst preparation conditions on the performance of eggshell cobalt/SiO2 catalysts for Fischer–Tropsch synthesis

Cited by 22 publications

References 68 publications

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

Performance Characteristics of Eggshell Co/SiO2 Fischer–Tropsch Catalysts: A Modeling Study

Contact Info

Product

Resources

About

Performance Characteristics of Eggshell Co/SiO₂ Fischer–Tropsch Catalysts: A Modeling Study