Catalytic conversion of bio-oil in supercritical water: Influence of RuO2/γ-Al2O3 catalysts on gasification efficiencies and bio-methane production

Jude Onwudili, Paul T Williams

Research output: Contribution to journalArticle

Abstract

Catalytic supercritical water gasification of heavy (dewatered) bio-oil has been investigated in a batch reactor in the presence of ruthenium catalysts in the form of RuO2 on γ-Al2O3 support. The reactions were carried out at temperatures of 400 °C, 450 °C and 500 °C and reaction times of up to 60 min using 15 wt% of bio-oil feed. Increased ruthenium oxide loading led to increased carbon gasification efficiencies (CGE) and bio-methane production. Hence, using the 20 wt% RuO2/γ-Al2O3 catalyst, CGE was 97.4 wt% at 500 °C and methane yield reached nearly 30 wt% of the bio-oil feed, which gave a CH4/CO2 molar ratio of 1.28. There was evidence that the RuO2 was involved in the initial conversion of the bio-oil to carbon oxides and hydrogen as well as the reduction of the CO2 to methane via CO methanation. However, competition for CO consumption via the water-gas shift reaction was also possible due to the large presence of water as the reaction medium. This work therefore demonstrates that high concentrations of heavy fraction of bio-oil can be catalytically converted to a methane-rich gas product under hydrothermal conditions at moderate temperatures. The calorific values of the gas product reached up to 54 MJ kg−1, which is nearly 3 times the HHV of the bio-oil feed.
Original languageEnglish
Pages (from-to)559-568
Number of pages10
JournalApplied Catalysis B
Volume181
Early online date17 Jul 2015
DOIs
Publication statusPublished - 1 Jan 2016

Fingerprint

Methane
Gasification
Oils
methane
catalyst
Catalysts
Water
oil
ruthenium
Ruthenium
Carbon
Carbon Monoxide
water
carbon
Gases
gas
oxide
Deuterium Oxide
Methanation
Calorific value

Bibliographical note

© 2015, Elsevier. Licensed under the Creative Commons
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

  • Hydrothermal gasificationCatalysisRuthenium oxideBio-methane

Cite this

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title = "Catalytic conversion of bio-oil in supercritical water: Influence of RuO2/γ-Al2O3 catalysts on gasification efficiencies and bio-methane production",
abstract = "Catalytic supercritical water gasification of heavy (dewatered) bio-oil has been investigated in a batch reactor in the presence of ruthenium catalysts in the form of RuO2 on γ-Al2O3 support. The reactions were carried out at temperatures of 400 °C, 450 °C and 500 °C and reaction times of up to 60 min using 15 wt{\%} of bio-oil feed. Increased ruthenium oxide loading led to increased carbon gasification efficiencies (CGE) and bio-methane production. Hence, using the 20 wt{\%} RuO2/γ-Al2O3 catalyst, CGE was 97.4 wt{\%} at 500 °C and methane yield reached nearly 30 wt{\%} of the bio-oil feed, which gave a CH4/CO2 molar ratio of 1.28. There was evidence that the RuO2 was involved in the initial conversion of the bio-oil to carbon oxides and hydrogen as well as the reduction of the CO2 to methane via CO methanation. However, competition for CO consumption via the water-gas shift reaction was also possible due to the large presence of water as the reaction medium. This work therefore demonstrates that high concentrations of heavy fraction of bio-oil can be catalytically converted to a methane-rich gas product under hydrothermal conditions at moderate temperatures. The calorific values of the gas product reached up to 54 MJ kg−1, which is nearly 3 times the HHV of the bio-oil feed.",
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AU - Williams, Paul T

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N2 - Catalytic supercritical water gasification of heavy (dewatered) bio-oil has been investigated in a batch reactor in the presence of ruthenium catalysts in the form of RuO2 on γ-Al2O3 support. The reactions were carried out at temperatures of 400 °C, 450 °C and 500 °C and reaction times of up to 60 min using 15 wt% of bio-oil feed. Increased ruthenium oxide loading led to increased carbon gasification efficiencies (CGE) and bio-methane production. Hence, using the 20 wt% RuO2/γ-Al2O3 catalyst, CGE was 97.4 wt% at 500 °C and methane yield reached nearly 30 wt% of the bio-oil feed, which gave a CH4/CO2 molar ratio of 1.28. There was evidence that the RuO2 was involved in the initial conversion of the bio-oil to carbon oxides and hydrogen as well as the reduction of the CO2 to methane via CO methanation. However, competition for CO consumption via the water-gas shift reaction was also possible due to the large presence of water as the reaction medium. This work therefore demonstrates that high concentrations of heavy fraction of bio-oil can be catalytically converted to a methane-rich gas product under hydrothermal conditions at moderate temperatures. The calorific values of the gas product reached up to 54 MJ kg−1, which is nearly 3 times the HHV of the bio-oil feed.

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