| 摘要 |
<p>1500610 Separating air NUOVO PIGNONE SpA 8 July 1975 [12 July 1974] 28762/75 Heading F4P A process of obtaining liquefied O 2 and/or N 2 comprises cooling feed air 20 in exchanger 1, partially liquefying the cooled air 21 by expanding it through a first turbine 4 and/or an expansion valve 2, and subjecting the partially liquefied air 23 to fractionation in a column 5 form which liquefied O 2 and/or N 2 can be withdrawn, the N 2 being withdrawn via line 24 and being used to cool feed air in exchanger 1 after which it is led via line 26 for expansion in a second turbine 10 driving a load 12, the pressure of the cooled air upstream of turbine 4 and/or valve 2 being 1 to 3 atmospheres greater than that of column 5. All or part of cooled air 21, depending on the degree of closure of valve 2, is slightly preheated in exchanger 3 in heat exchange with a portion of the N 2 from line 26 which has been compressed at 9. The N 2 is preheated at 6, before passing to exchanger 1, in heat exchange with part of the cooled air 21 which then passes via line 32, valve 13 and line 33 to column 5. After leaving turbine 10, the N 2 returns via line 30, exchanger 6 and line 30 to exchanger 1. Exchanger 3 may be omitted (Fig. 2, not shown), air drawn from further down column 5 may be employed as coolant for exchanger 1 (Figs. 3 and 4, not shown), and compressor 9 may be dispensed with (Figs. 5 and 6, not shown).</p> |
