PSAと分離膜の組合せによる常温ヘリウム精製システム

抄録

A new purification system, operated at ambient temperature, has been developed. It purifies He to 99.999% and the recovery ratio of He is 99%. This system consists of PSA (Pressure Swing Adsorption), membrane, freon refrigerator, and compressor. The PSA purifier has adsorption tanks which contain activated carbon and synthesis zeolite. It can purify impure He gas which is contaminated with H₂O, CO₂, O₂, Ar, and N₂ to 99.999% He. The purge gas from PSA is circulated and recompressed to recover He, because the recovery ratio of He in PSA is only 75%. The membrane purifier consists of a module which contains many hollow fibers of cellulose acetate. This system can separate impure components (CO₂, O₂, Ar, N₂) from He gas, which are condensed in the membrane, and exhausted. H₂O is condensed in the freon refrigerator and exhausted. Then it is adsorbed by PSA to a concentration where the dew point is below -70°C. Because impure components are fully condensed in the membrane and the freon refrigerator, the recovery ratio of He in this system is therefore above 99%.