2162. ------. [MATTOX, W. J.] (Standard Oil Development Co.). Process of Regenerating a Fluidized Fischer-Tropsch Catalyst. United States Patent 2,515,245, July 18, 1950; appl. filed June 11, 1947, Serial No. 754,027; 3 claims (Cl. 252-417). Chem. Abs., vol. 44, 1950, p. 8625.

Oxidizing treatment is carried out in at least 2 stages. In the 1^st step controlled oxidation of the active metal component of the carbonized catalyst takes place without appreciable combustion of C. In the 2d step, combustion of C on the catalyst takes place to the desired degree without appreciable further oxidation of the active metal component. Steam and/or CO₂ may be used as oxidizing gas in the 1^st stage and O₂, air, or air diluted with O₂ or steam is suitable for the 2d stage. Using CO₂ in the 1^st stage, the partial pressure ratio of CO : CO₂ should be slightly lower than .54, temperature 550° F. With steam, the partial pressure should be slightly lower than 27, temperature 550°; at temperature 600°-800° F. the CO : CO₂ partial pressure ratio may be 0.01-0.6 and the partial pressure ratios of H₂ : H₂O=0.5-27. The conditions for the 2d stage are more severe to remove the C from the pre-oxidized catalyst. Enough O₂ is kept available to remove the desired amount of C. C will burn in preference to further oxidation of the metal component. Temperature for 2d stage is 700°-1,400° F. and may be high enough to cause sintering. The decarburized catalyst may be returned to the reaction or, if desired, reduced before it is used again. The 1^st mild oxidation stage permits recovery of a major proportion of heavy hydrocarbons and waxes adsorbed on the catalyst in addition to the fixed C deposits. Highly phrophoric metal components of the carbonized catalyst are re-oxidized in the 1^st stage under conditions that do not result in sintering, thus conditioning the catalyst against undesired changes in the 2d stage. Depending on whether CO₂ or steam is used in the 1^st stage, the off gases are rich in CO or H₂ and may be added to the synthesis feed gas. Return of the unreduced, mildly oxidized catalyst directly to the synthesis stage may improve the yield of oxygenated compounds. The 2d stage gives a convenient means for economical sintering of synthesis catalyst such as pyrite ashes or other iron catalysts at high carbon concentration. Operating advantages include decreased O₂ requirements, considerable latitude in operating pressures, and lower oxidation temperatures. 16 United States patents cited.

------. See abs. 3826.