Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
On the effect of water on the Fischer-Tropsch rate over a Co-based catalyst: The influence of the H2/CO ratio
KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
2013 (engelsk)Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 214, s. 25-29Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The effect of water partial pressure on the Fischer-Tropsch (FT) rate of a cobalt catalyst supported on narrow-pore γ-Al2O3 was investigated at industrially relevant process conditions (483 K, 30 bar, pellet size: 53-90 μm). Inlet water partial pressure was varied up to 9 bar by external water vapour addition at different H2/CO molar ratios ranging from 1 to 3. The effect of water was found to be positive on FT-rate independently of the H2/CO ratio, but more significantly at H 2-poor condition. Temperature-programmed hydrogenation (TPH) was used to verify the presence of unreactive carbon species on the catalyst after 22 h on stream at the different conditions with and without exposure to about 9 bar water. A higher temperature feature that could be associated to amorphous polymeric carbon was detected at H2-poor conditions but remained unchanged upon 2 h of water exposure which did not result in a change in the amount of amorphous polymeric carbon detectable by TPH.

sted, utgiver, år, opplag, sider
2013. Vol. 214, s. 25-29
Emneord [en]
Amorphous polymeric carbon, Fischer-Tropsch, H2/CO ratio, Water
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-102311DOI: 10.1016/j.cattod.2012.10.015ISI: 000322693300005Scopus ID: 2-s2.0-84880328303OAI: oai:DiVA.org:kth-102311DiVA, id: diva2:552291
Forskningsfinansiär
Swedish Energy Agency
Merknad

QC 20130819. Updated from submitted to published.

Tilgjengelig fra: 2012-09-13 Laget: 2012-09-13 Sist oppdatert: 2017-12-07bibliografisk kontrollert
Inngår i avhandling
1. Fischer-Tropsch Synthesis over Cobalt-based Catalysts for BTL applications
Åpne denne publikasjonen i ny fane eller vindu >>Fischer-Tropsch Synthesis over Cobalt-based Catalysts for BTL applications
2012 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Fischer-Tropsch synthesis is a commercial technology that allows converting synthesis gas, a mixture of CO and H2, into fuels and chemicals. This process could be one of the actors in the reduction of oil dependency of the transportation sector. In fact, it has great potential for producing synthetic fuels also from renewable sources, such as biomass, after its thermochemical conversion (gasification) into synthesis gas. Concerning the quality of a diesel fuel produced with this technology, it has a lower local environmental impact than conventional diesel, since it is practically free of sulphur and nitrogen compounds and yields lower exhaust emissions of hydrocarbons, CO and particulates. The present study focuses on the use of cobalt-based catalysts for the production of diesel. In particular, it looks upon correlation between product selectivities when varying the catalyst properties and the effect of process parameters, such as a low H2/CO ratio, typical of a biomass-derived synthesis gas, and the water partial pressure.

Different cobalt-based catalysts, with different properties, such as conventional 3-dimensional porous network supports (γ-Al2O3, α-Al2O3, TiO2, SiO2), Co-loading, preparation technique, etc., were investigated in the Fischer–Tropsch reaction at industrially relevant process conditions. For a set of process conditions, a linear relationship seems to exist between the selectivity to methane (and other light products) and higher hydrocarbons (identified by the industrially relevant parameter SC5+, selectivity to hydrocarbons with more than 4 carbon atoms) indicating a common precursor.

Ordered mesoporous materials (SBA-15), characterized by a 1-dimensional mesoporous network, were tested as model supports and showed the possibility of occurrence of CO-diffusion limitations at diffusion distances much shorter than those required for conventional 3-dimensional porous network supports. The linear relationship mentioned above, derived for conventional supports, was shown to be an efficient tool for indicating whether measured selectivities are affected by CO-diffusion limitations. Some of the catalysts were exposed to H2-poor syngas and to external water addition and the effects on the selectivity relationships were investigated.

Furthermore, the possibility of internal water-gas shift of a H2-poor syngas with mixtures of Co/γ-Al2O3 and a Cu/ZnO/Al2O3 catalyst was investigated both as a technical solution for direct use of a model bio-syngas in the Fischer-Tropsch synthesis, and as a means to study the effect of indigenous water removal on the reaction rate to hydrocarbons. It was found that removal of indigenously produced water slows down the reaction rate significantly. Lastly, the effect of water partial pressure on the Fischer–Tropsch rate of the Co catalyst supported on narrow-pore γ-Al2O3, on its own, was studied. Inlet water partial pressure was varied by external water vapor addition at different H2/CO molar ratios ranging from 1 to 3. The effect of water showed to be positive on the rate for all the H2/CO ratios, but more significantly at H2-poor conditions. The nature of this positive effect on the rate seems to be unrelated to changes in amounts of amorphous polymeric carbon detectable by temperature-programmed hydrogenation of the spent catalyst.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2012. s. xiv, 95
Serie
Trita-CHE-Report, ISSN 1654-1081 ; 2012:36
Emneord
cobalt, Fischer-Tropsch, syngas, selectivity
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-102304 (URN)978-91-7501-446-3 (ISBN)
Disputas
2012-09-28, Q2, Osquldasväg 10 NB, KTH, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad

QC 20120914

Tilgjengelig fra: 2012-09-14 Laget: 2012-09-13 Sist oppdatert: 2012-09-14bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekstScopus

Søk i DiVA

Av forfatter/redaktør
Lualdi, MatteoLögdberg, SaraBoutonnet, MagaliJärås, Sven
Av organisasjonen
I samme tidsskrift
Catalysis Today

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 138 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf