PATENTS

      1549.  ------.  [I. G. FARBENINDUSTRIE, A. G.]  [Regeneration of Catalysts by Treatment With Oxygen-Containing Gases at raised Temperature.]  Italian Patent 386,631.  June 1, 1940.  Chem. Zentralb., 1942, II, p. 2626.

            Gas is passed through the catalyst at such increased velocity that is carries away the heat so that undesired increase in temperature does not occur.  It is best to begin with gases with low O₂ content, such as air, they continue with recirculation of the gas whereby it is cooled before its entrance into the catalyst to the catalyst temperature and gradually increase the O₂-content.  The method thus avoids temperature increases without retarding the regeneration.  The process is especially suitable for the regeneration of catalysts used in the conversion of carbonaceous substances, such as the cracking of hydrocarbons, pressure hydrogenation, and the production of hydrocarbons by the conversion of CO with H₂.