| 摘要 |
680,373. Separation of argon from air. GES. FUR LINDE'S EISMASCHINEN AKT.-GES. May 31, 1950 [June 20, 1949; Aug. 19, 1949], No. 13622/50. Class 8 (ii). Argon is separated from crude argon-nitrogen-oxygen fraction withdrawn from the low pressure column of a two stage air separation column (not shown) at a point where the oxygen and nitrogen contents are about equal by first removing the nitrogen by distillation in a column 2 Fig. 1, and subsequently separating the argon and oxygen in a separating column 11. In operation the crude argon mixture, after being cooled in a countercurrent heat exchanger 1 and a coil 6, enters the column 2 through a duct 7. Part of the separated nitrogen, which also contains argon and oxygen residues, serves to cool the exchanger 1, and the remaining nitrogen after expansion at a valve 25 cools high pressure nitrogen traversing an exchanger 8. This high pressure nitrogen after being liquefied in coils 17, 18 and further cooled in an exchanger 19 is expanded at a valve 20 and cools a condenser 27, thereby providing the necessary cold for the separation in column 11. The thus warmed nitrogen is discharged through exchangers 19, 8. Liquid argon-oxygen mixture from the base of the column 2 after expansion at a valve 10 is rectified in the column into pure argon gas which leaves through a duct. 14, and into substantially pure liquid oxygen which is forced by a motor driven pump 15 to the vaporising space of a condenser 4 at the head of column 2, from which the major portion of oxygen gas is discharged through a duct 21; the remainder being returned to the column 11. In a modification the cold requirement for the argon-oxygen separation column 36, Fig. 2, is provided by expansion of crude argon and of compressed air in a crude argon circuit and a compressed air circuit respectively. In operation crude argon, including the portion to be separated, after traversing a compressor 32, an aftercooler 33, a countercurrent heat exchanger 34 and a liquefying coil 46 is expanded at a valve 37 and vaporised in a coil 38, thus cooling the head of the column 36; the portion of crude argon to be separated being expanded at a valve 40 before entering the distillation column 39. The crude argon circuit is completed through exchangers 60, 34. The compressed air after traversing countercurrent heat exchangers 63, 56 liquefying coils 41, 47 expansion valves 43, 48 and the exchanger 60 is divided into one portion which is expanded at a valve 44, and serves as sprinkling liquid in the column 39, and a second portion which after expansion at a valve 49 is vaporised in condenser tubes 52, thus cooling the head of the column 36. Vaporised air is joined by nitrogen from the column 39 before entering the exchanger 63, liquid argon product leaves at a duct 59 and oxygen gas by a duct 55. Specification 358,842 is referred to.
|
