| 摘要 |
PURPOSE:To make it possible to realize the drastic shortening of a precooling time without employing complicated constitution, by enabling the recovery of a cryogen after the cryogen introduced into a reboiler at a start time raised through a distillation tower from the reboiler. CONSTITUTION:A hydrogen isotope gaseous mixture 24 being a stock material to be distilled is cooled to predetermined temp. by a stock material cooling heat exchanger 22 to be introduced into a distillation tower 1 and distilled to obtain a gaseous fraction 26 high in the ratio of a light component and a distillate 27 high in the ratio of a heavy component while both of them are respectively recovered as products through valves 28, 29. Cryogen introducing piping 11 is provided to the reboiler 1c of the distillation tower 1 from a freezer 21 and, at the time of precooling, the cryogen is guided to the reboiler 1c of the distillation tower 1 from a freezer 21 and, at the time of precooling, the cryogen is guided to the reboiler 1c from the freezer 21 and the pressure in the distillation tower 1 is raised and the cryogen is discharged or recovered from a gaseous fraction outlet through the valve 28 and cryogen discharge piping 26 to be returned to the freezer 21. As the generation source of the cryogen, the freezer 21 may not be used and, for example, liquid helium or liquid hydrogen may be used. |
