PATENTS

      37.              ARNOLD, J. H., AND GROSSELFINGER, F. B.  Synthesis of Liquid Hydrocarbons.  United States Patent 2,628,970, Feb. 17, 1953: appl. Filed July 7, 1950. Serial No. 172,478: 4 claims (Cl. 260-449.6).

Long catalyst life and high yield of liquid products is achieved by maintaining a high H₂ concentration during the course of the synthesis.  Inlet concentration of H₂ is restricted to 40-50 vol. % and outlet concentration of H₂ is restricted to 40-50 vol. % and outlet concentration to 25-30 vol. %.  The reaction gases must be withdrawn from the synthesis zone before the H₂ content has fallen <20 vol. % and when the CO content of the reaction stream is preferably 2-3 vol. %.  Tail gas substantially free of C₂ and higher hydrocarbons is withdrawn and recycled to the gas-generation and to the synthesis zones.  1-15% by volume of the recycled tail gas is returned to the gas-generation zone and the remainder to the synthesis zone.  4 United States Patents cited.