GB402479A - Improvements in or relating to the adsorption of gases or vapors - Google Patents

Abstract

<PICT:0402479/III/1> Condensible gases or vapours are removed from gaseous mixtures by passing them successively into contact with two batches of adsorbent such as silica gel, conditioning the mixture to activate one batch and charge the other with the condensible components, removing any condensible gases in passing between the batches, and periodically reversing the position of the batches in the circuit. According to the arrangement shown, the gas mixture, for example moist compressed air, enters by pipe 15 and is heated by the steam heater 17, its relative humidity being lowered. It is then passed by suitable valves through the adsorber 10 which contains partially saturated absorbent from a prior operation. The heated air takes up the mixture in the absorbent until it is saturated, thus activating the adsorbent. The air is then passed via the pipe 22 through the cooling jacket 31 where it is cooled sufficiently to cause the moisture to condense. The condensed moisture is removed by the trap 25 and the air is then passed via pipe 27 to the adsorber 11 containing adsorbent activated in a previous operation, so that final traces of moisture are removed, and dry air is discharged through pipe 41. When the adsorbent in adsorber 11 is saturated, the position of the adsorbers in the cycle of operations is reversed by suitable valve means. The activated adsorbent, e.g. in adsorber 10 in the above example, may be cooled after activation by shutting off steam in the heater 17 or bye-passing the heater by means of pipe 36. This elimination of heating may be performed at the latter end of the activating cycle. More than two adsorbers may be used, and the spare adsorbers may be cooled by radiation or a cooling fluid, or they may be placed in the stream of effluent dried air, which may be previously cooled. The process may be applied to the dehydration of compressed air, atmospheric air or other gases, and the recovery of volatile solvents. Where the gas mixtures are at an elevated temperature, the heater 17 may be reduced in size or omitted.