Change search
ReferencesLink to record
Permanent link

Direct link
The effect of catalyst pellet size on nickel carbonyl-induced particle sintering under low temperature CO methanation
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.ORCID iD: 0000-0003-3826-1858
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
Show others and affiliations
2016 (English)In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 514, 91-102 p.Article in journal (Refereed) PublishedText
Abstract [en]

Abstract The present work aims to evaluate the effect of catalyst pellet size on deactivation due to nickel carbonyl-induced particle sintering. For that purpose, a γ-Al2O3-supported nickel catalyst was prepared and tested under low temperature and high CO partial pressure. A total of four different pellet sizes were employed in the present study. It was found that the deactivation rate decreases with increasing pellet size. A very severe deactivation was observed when using small pellets. Large pellets exhibited instead a more stable performance. This difference in catalyst stability was explained by X-ray diffraction analyses which revealed that the growth of the nickel particles was very severe when using small pellets. An evaluation of heat and mass transfer phenomena in these four pellets was also conducted. It was found that, under the present low temperature reaction conditions, the temperature at the catalyst external surface can greatly differ from that in the bulk gas when using sufficiently large pellets. It was also shown that, for large pellets, the major part of the interior of the catalyst is exposed to negligible CO partial pressures and high temperatures, fact that can reduce the potential for nickel carbonyl formation.

Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 514, 91-102 p.
Keyword [en]
Methanation, Deactivation, Nickel carbonyl, Sintering, Heat and mass transfer, Alumina
National Category
Chemical Process Engineering
Identifiers
URN: urn:nbn:se:kth:diva-182353DOI: 10.1016/j.apcata.2015.12.034ISI: 000371551200010ScopusID: 2-s2.0-84955264386OAI: oai:DiVA.org:kth-182353DiVA: diva2:904227
Funder
EU, FP7, Seventh Framework Programme, 308733
Note

QC 20160330. QC 20160407

Available from: 2016-02-18 Created: 2016-02-18 Last updated: 2016-08-17Bibliographically approved
In thesis
1. Deactivation of cobalt and nickel catalysts in Fischer-Tropsch synthesis and methanation
Open this publication in new window or tab >>Deactivation of cobalt and nickel catalysts in Fischer-Tropsch synthesis and methanation
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

            A potential route for converting different carbon sources (coal, natural gas and biomass) into synthetic fuels is the transformation of these raw materials into synthesis gas (CO and H2), followed by a catalytic step which converts this gas into the desired fuels. The present thesis has focused on two catalytic steps: Fischer-Tropsch synthesis (FTS) and methanation. The Fischer-Tropsch synthesis serves to convert synthesis gas into liquid hydrocarbon-based fuels. Methanation serves instead to produce synthetic natural gas (SNG). Cobalt catalysts have been used in FTS while nickel catalysts have been used in methanation.

            The catalyst lifetime is a parameter of critical importance both in FTS and methanation. The aim of this thesis was to investigate the deactivation causes of the cobalt and nickel catalysts in their respective reactions.

            The resistance to carbonyl-induced sintering of nickel catalysts supported on different carriers (γ-Al2O3, SiO2, TiO2 and α-Al2O3) was studied. TiO2-supported nickel catalysts exhibited lower sintering rates than the other catalysts. The effect of the catalyst pellet size was also evaluated on γ-Al2O3-supported nickel catalysts. The use of large catalyst pellets gave considerably lower sintering rates. The resistance to carbon formation on the above-mentioned supported nickel catalysts was also evaluated. Once again, TiO2-supported nickel catalysts exhibited the lowest carbon formation rates. Finally, the effect of operating conditions on carbon formation and deactivation was studied using Ni/TiO2 catalysts. The use of higher H2/CO ratios and higher pressures reduced the carbon formation rate. Increasing the temperature from 280 °C to 340 °C favored carbon deposition. The addition of steam also reduced the carbon formation rate but accelerated catalyst deactivation.

            The decline in activity of cobalt catalysts with increasing sulfur concentration was also assessed by ex situ poisoning of a cobalt catalyst. A deactivation model was proposed to predict the decline in activity as function of the sulfur coverage and the sulfur-to-cobalt active site ratio. The results also indicate that sulfur decreases the selectivity to long-chain hydrocarbons and olefins.

Place, publisher, year, edition, pages
Stockholm: US-AB, 2016. xii, 124 p.
Series
TRITA-CHE-Report, ISSN 1654-1081
Keyword
cobalt, nickel, Fischer-Tropsch synthesis, methanation, deactivation, carbonyl, sintering, carbon fomation. sulfur, poisoning
National Category
Other Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-190593 (URN)978-91-7729-060-5 (ISBN)
Public defence
2016-09-23, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
EU, FP7, Seventh Framework Programme, 308733
Note

QC 20160817

Available from: 2016-08-17 Created: 2016-08-12 Last updated: 2016-08-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopusScience Direct

Search in DiVA

By author/editor
Barrientos, JavierLualdi, MatteoBoutonnet, MagaliJärås, Sven
By organisation
Chemical Technology
In the same journal
Applied Catalysis A: General
Chemical Process Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 107 hits
ReferencesLink to record
Permanent link

Direct link