OXIDATION OF METHANE TO SYNTHESIS GAS IN A FLUIDIZED-BED REACTOR USING MGO-BASED CATALYSTS

Ni(15%)/MgO and Co(12%)/MgO have been used as catalysts to carry out t he oxidation of methane to synthesis gas in a fluidized-bed reactor. T he fresh and used catalysts have been characterized through a battery of instrumental techniques aiming at finding the relationship among th e operating conditions, activity, and stability of the reacting system . The fresh catalysts are made up of a mixture of crystalline MgO and MgMO(2) (M = Ni or Co) while the used ones also contain NiO and CoO. T his explains the on-stream activation of the solid in terms of an in s itu reduction of the oxides to generate the metallic centers needed to catalyze the reforming reaction. Under some of the experimental condi tions employed, the SEM micrographs of the used solids show coke forma tion in whiskers. These will be burnt in the oxidizing zone of the flu idized bed, thus releasing Ni particles, which may be deposited on the freeboard walls. These metallic particles can catalyze back reactions , decreasing the overall yield to the desired reaction products, CO an d H-2. (C) 1996 Academic Press, Inc.