Oxidative coupling of methane: catalytic behaviour assessment via comprehensive microkinetic modelling

V. I. Alexiadis, J. W. Thybaut, P. N. Kechagiopoulos, M. Chaar, A. C. Van Veen, M. Muhler, G. B. Marin

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

A comprehensive microkinetic model, including catalyst descriptors, that accounts for thermal, homogeneous and catalytic, heterogeneous reaction steps in the oxidative coupling of methane has been used in the assessment of kinetic data acquired on different catalysts. The applicability of the model was extended from alkali magnesia catalysts represented by Li/MgO and Sn-Li/MgO, to a new class of materials, namely alkaline earth-promoted lanthana catalysts, represented by Sr/La2O3. To simulate adequately the large experimental dataset, acquired with the latter catalyst, the surface reaction network of the microkinetic model was expanded. The resulting model succeeded in adequately simulating the C-2, that is, ethane and ethene, production, both individually and as a lump during regression. It was found that the activity of Sr/La2O3, in terms of methane conversion, is 33 and five times higher than that of Li/MgO and Sn-Li/MgO, respectively. This is attributed mainly to the higher stability of adsorbed hydroxyl, the higher stability of adsorbed oxygen, and the higher active density of Sr/La2O3. The selectivity toward C-2 products was found to depend on the methyl radical sticking coefficient and the stability of the adsorbed oxygen and was the highest on the Sn-promoted LiMgO catalyst, that is, 70% at about 5% methane conversion at 1023 K, 190 kPa, and inlet molar CH4/O-2 ratio of 4. (C) 2014 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)496-505
Number of pages10
JournalApplied Catalysis B: Environmental
Volume150-151
Early online date1 Jan 2014
DOIs
Publication statusPublished - 5 May 2014

Keywords

  • ethylene
  • homogeneous-heterogeneous reaction network
  • rare earth catalyst
  • LiMgO catalyst
  • kinetics
  • pressure
  • design
  • ethane
  • performance
  • surfaces
  • enthalpy

Cite this

Oxidative coupling of methane : catalytic behaviour assessment via comprehensive microkinetic modelling. / Alexiadis, V. I.; Thybaut, J. W.; Kechagiopoulos, P. N.; Chaar, M.; Van Veen, A. C.; Muhler, M.; Marin, G. B.

In: Applied Catalysis B: Environmental, Vol. 150-151, 05.05.2014, p. 496-505.

Research output: Contribution to journalArticle

Alexiadis, V. I. ; Thybaut, J. W. ; Kechagiopoulos, P. N. ; Chaar, M. ; Van Veen, A. C. ; Muhler, M. ; Marin, G. B. / Oxidative coupling of methane : catalytic behaviour assessment via comprehensive microkinetic modelling. In: Applied Catalysis B: Environmental. 2014 ; Vol. 150-151. pp. 496-505.
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abstract = "A comprehensive microkinetic model, including catalyst descriptors, that accounts for thermal, homogeneous and catalytic, heterogeneous reaction steps in the oxidative coupling of methane has been used in the assessment of kinetic data acquired on different catalysts. The applicability of the model was extended from alkali magnesia catalysts represented by Li/MgO and Sn-Li/MgO, to a new class of materials, namely alkaline earth-promoted lanthana catalysts, represented by Sr/La2O3. To simulate adequately the large experimental dataset, acquired with the latter catalyst, the surface reaction network of the microkinetic model was expanded. The resulting model succeeded in adequately simulating the C-2, that is, ethane and ethene, production, both individually and as a lump during regression. It was found that the activity of Sr/La2O3, in terms of methane conversion, is 33 and five times higher than that of Li/MgO and Sn-Li/MgO, respectively. This is attributed mainly to the higher stability of adsorbed hydroxyl, the higher stability of adsorbed oxygen, and the higher active density of Sr/La2O3. The selectivity toward C-2 products was found to depend on the methyl radical sticking coefficient and the stability of the adsorbed oxygen and was the highest on the Sn-promoted LiMgO catalyst, that is, 70{\%} at about 5{\%} methane conversion at 1023 K, 190 kPa, and inlet molar CH4/O-2 ratio of 4. (C) 2014 Elsevier B.V. All rights reserved.",
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note = "Acknowledgement This article reports the work undertaken in the context of the project “OCMOL, Oxidative Coupling of Methane followed by Oligomerization to Liquids.” OCMOL is a large-scale collaborative project supported by the European Commission in the 7th Framework Programme (GA n 228953). For further information about OCMOL, see http://www.ocmol.eu.",
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AU - Muhler, M.

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N2 - A comprehensive microkinetic model, including catalyst descriptors, that accounts for thermal, homogeneous and catalytic, heterogeneous reaction steps in the oxidative coupling of methane has been used in the assessment of kinetic data acquired on different catalysts. The applicability of the model was extended from alkali magnesia catalysts represented by Li/MgO and Sn-Li/MgO, to a new class of materials, namely alkaline earth-promoted lanthana catalysts, represented by Sr/La2O3. To simulate adequately the large experimental dataset, acquired with the latter catalyst, the surface reaction network of the microkinetic model was expanded. The resulting model succeeded in adequately simulating the C-2, that is, ethane and ethene, production, both individually and as a lump during regression. It was found that the activity of Sr/La2O3, in terms of methane conversion, is 33 and five times higher than that of Li/MgO and Sn-Li/MgO, respectively. This is attributed mainly to the higher stability of adsorbed hydroxyl, the higher stability of adsorbed oxygen, and the higher active density of Sr/La2O3. The selectivity toward C-2 products was found to depend on the methyl radical sticking coefficient and the stability of the adsorbed oxygen and was the highest on the Sn-promoted LiMgO catalyst, that is, 70% at about 5% methane conversion at 1023 K, 190 kPa, and inlet molar CH4/O-2 ratio of 4. (C) 2014 Elsevier B.V. All rights reserved.

AB - A comprehensive microkinetic model, including catalyst descriptors, that accounts for thermal, homogeneous and catalytic, heterogeneous reaction steps in the oxidative coupling of methane has been used in the assessment of kinetic data acquired on different catalysts. The applicability of the model was extended from alkali magnesia catalysts represented by Li/MgO and Sn-Li/MgO, to a new class of materials, namely alkaline earth-promoted lanthana catalysts, represented by Sr/La2O3. To simulate adequately the large experimental dataset, acquired with the latter catalyst, the surface reaction network of the microkinetic model was expanded. The resulting model succeeded in adequately simulating the C-2, that is, ethane and ethene, production, both individually and as a lump during regression. It was found that the activity of Sr/La2O3, in terms of methane conversion, is 33 and five times higher than that of Li/MgO and Sn-Li/MgO, respectively. This is attributed mainly to the higher stability of adsorbed hydroxyl, the higher stability of adsorbed oxygen, and the higher active density of Sr/La2O3. The selectivity toward C-2 products was found to depend on the methyl radical sticking coefficient and the stability of the adsorbed oxygen and was the highest on the Sn-promoted LiMgO catalyst, that is, 70% at about 5% methane conversion at 1023 K, 190 kPa, and inlet molar CH4/O-2 ratio of 4. (C) 2014 Elsevier B.V. All rights reserved.

KW - ethylene

KW - homogeneous-heterogeneous reaction network

KW - rare earth catalyst

KW - LiMgO catalyst

KW - kinetics

KW - pressure

KW - design

KW - ethane

KW - performance

KW - surfaces

KW - enthalpy

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DO - 10.1016/j.apcatb.2013.12.043

M3 - Article

VL - 150-151

SP - 496

EP - 505

JO - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

SN - 0926-3373

ER -