100.    AUDAS, F. G.  Continuous Dry Process for the Removal of Hydrogen Sulfide From Industrial Gases.  Coke and Gas, vol. 13, 1951, pp. 229-234; Chem. Abs., vol. 46, 1952, p. 11,638.

                  This is a new process in the pilot-plant stage of removal of H₂S from industrial gases.  According to the following reaction:  2H₂S+SO₂=2H₂O+3S, H₂S is removed by adding SO₂ in small excess of the above reaction and passing the mixture through a bed of alumina at 60°-90° at such a rate that it emerges from the chamber containing the bed completely free of H₂S.  The spent alumina is continuously withdrawn from the bottom of the reaction chamber for regenerative treatment, while regenerated material is continuously added at the top.  Regeneration of spent alumina consists of heating at 500° by passing hot gases through the bed of alumina in the regenerating vessel.  The process can be readily adapted for simultaneous recovery of C₆H₆ which is absorbed on the alumina in the purifier and can be recovered by heating to 140° in a steam-coil-heated chamber. This C₆H₆ recovery required the introduction of a desorption vessel between the purifier and the regenerator.  A detailed approximate evaluation of costs is given.