High-temperature parallel screening of catalysts for the oxidative coupling of methane

• Published in: Catalysis today Vol. 137; no. 1; pp. 80 - 89
• Main Authors: Olivier, Louis, Haag, Stéphane, Pennemann, Helmut, Hofmann, Christian, Mirodatos, Claude, van Veen, Andre C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30.08.2008; Elsevier Science
• Subjects: Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; OCM; Parallel reactor; Reactor design; Temperature stability; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; OCM; Parallel reactor; Reactor design; Temperature stability; Methane; Calcium oxide; Atmospheric pressure; Lithium; Selectivity; High temperature; Oxidative coupling; Design; Strontium; Formulation; Lanthanum; Mass spectrometer; Deactivation; Stability; Device; Magnesium oxide; Fixed bed reactor; Operating conditions; Temperature measurement; Heterogeneous catalysis; Screening; Time resolution; Partial pressure; Parallel reactor,OCM,Temperature stability,Reactor design; Catalyst
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2008.02.024

The oxidative coupling of methane (OCM) was investigated with a specifically designed multi-channel device operating fixed-bed reactors at high temperature and atmospheric pressure. The device allows precise temperature measurement in each channel selected for analysis and possesses a quench cooling unit right after the reaction zone. Analysis is based on a mass spectrometer allowing a time resolution of only 3 s per analysis and 30 s per reactor channel. Successful screening is demonstrated using a reactant feed of O 2 and CH 4 diluted in Ar at flows between 100 and 166 mL/min per reactor channel. As expected, Li/MgO-based catalysts showed good initial performance, but rapid deactivation at 800 °C excludes their use in high-temperature applications. Good C 2 selectivity up to 80% and high yields up to 20% were observed for La/Sr/CaO catalysts. Even more interesting, no decline in performance was observed for those formulations identifying 10% La/20% Sr/CaO as best catalyst in an initial library. Screening of various La and Sr loadings at different operating conditions identified a optimal content of 5–10% for La and 20% for Sr. The exploration of operating conditions showed increasing C 2 productivities with increasing reactant partial pressure, reaching at 800 °C values up to 1.3 × 10 −5 mol (C 2) s −1 g(cat) −1.