Verfahren und Anlage zur gemischten Herstellung von Sauerstoff hoher und niederer Reinheit

摘要

A process for producing simultaneously both high and low purity oxygen, which comprises: a) passing a compressed and cooled feed stream (101) containing at least oxygen and nitrogen to a main exchanger (11), wherein the compressed and cooled feed stream is divided into two fractions (A) and (B), b) expanding the first fraction (A) (103) in an expander (12) and dividing the same into two further fractions (i) and (ii), c) further cooling the second fraction (B) (104) in the main exchanger and expanding at least a fraction of this stream by an expansion valve (130a) into a high pressure column (20) as liquid feed stream, d) introducing the first fraction (i) (106) into a reboiler (24) located at the bottom of the low pressure distillation column (21), whereby the first fraction of the feed stream condenses in the reboiler providing a first reboil for distillation, e) feeding at least a fraction of the resulting liquefied feed stream (110) to either or both high and low pressure column as feed, f) introducing the second fraction (ii) (107) to the bottom of the high pressure column as gaseous feed, whereby a bottom oxygen-rich liquid stream and an overhead nitrogen-rich gaseous stream are formed, g) passing the oxygen-rich liquid stream (108) to the low pressure column as feed, h) condensing the nitrogen-rich gaseous stream against a boiling liquid in the upper reboiler (23) of the low pressure column, located at an intermediate stage, thereby serving as a second reboil for distillation, i) returning a portion (115) of the condensed nitrogen-rich stream to the high pressure column as reflux, and passing at least a fraction of the remaining portion (116) of the nitrogen-rich stream to the top of the low pressure column as reflux, whereby the low pressure column separates its feed into bottom stream oxygen products and top stream rich in nitrogen, j) recovering the bottom stream oxygen product (118) as high purity liquid oxygen, k) drawing from a tray or a stage between the two reboilers of the low pressure column, the stream oxygen product of low purity oxygen (119), and l) warming in the main exchange (11) the low purity oxygen stream, and the nitrogen-rich stream.