Claims
- 1. A process for the separation of air in a cryogenic distillation apparatus comprising a distillation column and in which air is separated to produce a fraction rich in oxygen and a fraction rich in nitrogen as products, comprising maintaining the purities of said product substantially constant during variations of the flow rate or of the pressure of the supply air by controlling the relative liquid to vapor interstage transfer rate within said distillation column in response to said variations of the flow rate or of the pressure of said supplied air, by increasing the relative liquid to vapor interstage transfer rate in said distillation column when the demand for the product or the flow rate of the supplied air increases, and decreasing the relative liquid to vapor interstage transfer rate in said distillation column when the demand for the product or the flow rate of the supplied air decreases by maintaining the liquid in the sump of the distillation column at a predetermined level by means of a sump level controller having a set point set at a predetermined level; and controlling said sump level solely in dependence on the flow rate of air to the column.
- 2. A process according to claim 1 wherein the distillation apparatus comprises a condenser in heat exchange relation with said sump liquid.
Priority Claims (2)
Number |
Date |
Country |
Kind |
93 05062 |
Apr 1993 |
FRX |
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93 11509 |
Sep 1993 |
FRX |
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Parent Case Info
This is a continuation of application Ser. No. 08/509,137, filed Jul. 31, 1995, now U.S. Pat. No. 5,592,834, Issued Jan. 14, 1997 which is a divisional of application Ser. No. 08/230,521, filed Apr. 20, 1994, now U.S. Pat. No. 5,437,160, Issued Aug. 1, 1995.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4566887 |
Openshaw |
Jan 1986 |
|
5152149 |
Mostello et al. |
Oct 1992 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
230521 |
Apr 1994 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
509137 |
Jul 1995 |
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