초록 ▼

A cryogenic rectification system for producing nitrogen having a low argon content wherein the reflux ratio in the upper portion of the higher pressure column of a double column system is modified by withdrawing nitrogen vapor from below the top of the column, liquefying the withdrawn vapor, and ret

A cryogenic rectification system for producing nitrogen having a low argon content wherein the reflux ratio in the upper portion of the higher pressure column of a double column system is modified by withdrawing nitrogen vapor from below the top of the column, liquefying the withdrawn vapor, and returning the liquefied nitrogen to the column at or near the withdrawal point and below the top of the column.

대표청구항 ▼

A cryogenic rectification method for producing nitrogen having a low argon content comprising: (A) passing feed air into a higher pressure column of a double column which also includes a lower pressure column and separating the feed air within the higher pressure column into nitrogen-enriched fluid

A cryogenic rectification method for producing nitrogen having a low argon content comprising: (A) passing feed air into a higher pressure column of a double column which also includes a lower pressure column and separating the feed air within the higher pressure column into nitrogen-enriched fluid and into oxygen-enriched fluid; (B) passing oxygen-enriched fluid and nitrogen-enriched fluid from the higher pressure column into the lower pressure column; (C) withdrawing nitrogen-containing vapor from the higher pressure column at a level from 3 to 10 equilibrium stages below the top of the higher pressure column; (D) liquefying the withdrawn nitrogen-containing vapor to produce liquefied nitrogen and passing the liquefied nitrogen into the higher pressure column at a level within 5 equilibrium stages of the level from which the nitrogen-containing vapor is withdrawn from the higher pressure column and below the top of the higher pressure column; and (E) recovering a portion of the nitrogen-enriched fluid as low argon content nitrogen product.