| 摘要 |
<p>A process and apparatus for the ultrapurification of cryogenic low boiling liquified gases such as oxygen and nitrogen which contain trace impurities. The impure gas (20) is introduced into a first distillation column (32) and is substantially at its liquid-gas equilibrium temperature at the pressures within the first distillation column. Here the gas is separated by distillation into a first vapor fraction (100) containing low boiling point impurities and a first liquid fraction (38) containing high boiling point impurities. The first vapor fraction is withdrawn and introduced into a second distillation column (52).The first vapor fraction is substantially at the liquid-gas equilibrium temperature at the pressures within the second distillation column. Here the vapor fraction is separated by distillation into a second vapor fraction (94) containing high boiling point impurities and a second liquid fraction (60) free of trace impurities which is withdrawn as product. Cooling for the process is provided by indirect heat exchange with a cryogenic low boiling gas such as nitrogen, oxygen, or air. The gas to be purified as well as the heat exchange gas can be obtained from a standard air separation unit or the process can be conducted using gases obtained from storage.</p> |
