DEACTIVATION OF FIBER-SUPPORTED LA0.65SR0.35NI0.29CO0.69FE0.02O3 CATALYST BY MERCAPTAN DURING COMBUSTION OF METHANE OR NATURAL-GAS

A fiber-supported La0.65Sr0.35Ni0.29Co0.69Fe0.02O3 perovskite combusti on catalyst has been developed. The preparation technique consisted of in-situ perovskite formation via incipient fiber blanket wetting, fol lowed by freeze-drying. The catalyst activity, per gram of perovskite, is higher than that of unsupported fine La0.65Sr0.35Ni0.29Co0.69Fe0.0 2O3 powder. Kinetics of deactivation of this catalyst by sulfur oxides , resulting from total oxidation of methyl-mercaptan during methane an d natural gas combustion, has been studied in a CSTR Berty reactor. Th e effects of temperature, methane contact time and mercaptan concentra tion, as well as combustion products were evaluated. The experimental data has been fitted by a simple deactivation model based on Levenspie l's formalism. The observed deactivation rates were relatively slow in comparison to known deactivation rates by sulfur dioxide of some tran sition metal based catalysts, In particular, the catalyst seems to tol erate mercaptan concentration levels, commonly used to odorize commerc ial natural gas, as confirmed by long term tests in an integral reacto r. (C) 1997 Elsevier Science B.V.