TY - JOUR
T1 - Oxidative coupling of methane
T2 - catalytic behaviour assessment via comprehensive microkinetic modelling
AU - Alexiadis, V. I.
AU - Thybaut, J. W.
AU - Kechagiopoulos, P. N.
AU - Chaar, M.
AU - Van Veen, A. C.
AU - Muhler, M.
AU - Marin, G. B.
N1 - 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.
PY - 2014/5/5
Y1 - 2014/5/5
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
U2 - 10.1016/j.apcatb.2013.12.043
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 -
