| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a plant for separating nitrogen, oxygen and argon from air which are small in power consumption, and high in argon yield and oxygen-rich fraction yield. SOLUTION: An air stream is introduced from an inlet 12 into a two-stage rectification column including a high pressure rectification column and a low pressure rectification column 6, and separated into an oxygen-rich fraction and a nitrogen-rich fraction. The argon-enriched oxygen vapor flows from an outlet 16 of the lower pressure rectification column into a side column 52 to separate argon. The oxygen-enriched air stream is sampled from the outlet 16 of the high pressure rectification column. A vaporous oxygen-enriched air stream is introduced into the lower pressure rectification column from an inlet 46. At least, part of the oxygen-enriched liquid is partially reboiled in a reboiler 22, and separated in a rectification column 22 to form a vapor depleted of oxygen and a liquid air stream further enriched liquid. A stream of the enriched liquid is vaporized to form an oxygen-enriched vapor to be introduced in the low pressure rectification column from the inlet. A part of the oxygen-depleted vapor is condensed, and sampled as a product or re-introduced in the low pressure rectification column. |
