1262.    ---------------.  [GRIMME, W.] [Gasoline Products by Direct Synthesis.  German Developments in the Fischer-Tropsch Process.]  Oel u. Kohle u. Brennstoff-Chem., June 1, 1944; Chem. Trade Jour., vol. 117, 1945, pp. 289-290.

       Recovery of the lower-boiling products produced in the Fischer-Tropsch process is discussed.  The activated C process is employed.  The Fischer-Tropsch feed gas generally contains 15-20% of inert constituents such as CH₄, CO₂ and N₂.  From such a gas about 1/3 leaves the catalyst chamber in gaseous form, the hydrocarbons in this exit-gas mixture containing 40-50% of the total hydrocarbons produced in the conversion.  Even after cooling, it still contains 200 gm. of gasoline and gas oil per m.³  The activated C, arranged in a tower, has a selective adsorptive action on the gas constituents, the gasoline and gas oil being taken up first.  The lower portions of the C become saturated first with gasoline, this gradually displacing upward the lighter hydrocarbons and other products until, at the end of the operation, the C has adsorbed about 5% of its weight of gasoline, which is recovered by steaming.  The operation is effected on a large scale in groups of 4 adsorbing columns, 1 of these being cut out automatically in series for regeneration.  The lower hydrocarbons recovered may be used for the synthesis of high-octane fuels.