GB782901A - Process and apparatus for separation of gaseous components from gaseous mixtures - Google Patents

Abstract

<PICT:0782901/IV (a)/1> Mono - acetylene is removed from a gaseous mixture by contacting it in an absorbing zone with a watermiscible solvent having selective dissolving power for acetylene, removing the acetylene - enriched solvent from the absorbing zone and passing it through a desorbing zone in countercurrent to a stream of gases stripped from the solvent in a subsequent stripping zone of the process, removing a stream of substantially pure mono-acetylene from the desorbing zone, separately removing partially desorbed solvent containing high acetylenes and the remainder of the dissolved mono-acetylene from the desorbing zone and stripping the partially desorbed solvent by reducing the pressure on the solvent in the stripping zone in at least two successive stages operating at successively lower pressures for the liberation of the remainder of dissolved mono-acetylene, returning dissolved gases liberated in the second or later stripping stage to the immediately preceding stripping stage, and returning dissolved gases liberated in the first stripping stages to the desorbing zone as the said countercurrent stream of gases. In an example, a fresh cracked gas containing 8.5 per cent of acetylene is mixed with recycle gas from conduit 13 and is fed through compressors 11 and 12 and is then absorbed in a water-soluble organic solvent such as butyrolactone, alphapyrrolidone, dimethyl formamide or glutarimide in absorber 15. Waste gases leave through conduit 19. The solvent then passes to desorber 20 at a lower pressure, in which most of the acetylene is liberated and withdrawn via pipe 21. The solvent is withdrawn via pipe 23 and passes into a flash tower 22 which consists of three sections 29, 30 and 31 joined by conduits 32 and 33. When the solvent passes from chamber 29 to chamber 30 additional acetylene is liberated and is passed back to the desorber by line 28. Live steam is provided through a conduit 40 to a steam jet ejector pump 39 which removes acetylene and other uncondensed material from receiver 36 through conduit 41. Solvent containing the higher unwanted acetylenes pass via pipe 53 to a stripper 54 from which the overhead product passes to a barometric condenser 64 in which the steam is condensed. Specification 702,876 is referred to.