High pressure oxygen pumped LOX rectifier
OwnerDonald C. Ericksoninventor
Life of this patent
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Abstract
A process and apparatus are disclosed for producing pressurized oxygen at up to about 10 ATA directly in a cryogenic distillation process without need of an oxygen compressor. The process involves a split supply pressure air supply wherein the elevated pressure fraction gasifies pumped liquid oxygen. An essential aspect of the invention is that this gasification takes place in an elevated pressure rectifier; thus the elevated pressure fraction of air is converted into partially separated liquids as opposed to the more wasteful conversion to liquid air which occurs in the conventional process. The improvement may be adapted to any cryogenic distillation configuration and be used to produce any purity of product oxygen. A particularly high purity (99.5%) and low energy example is presented.
Claims15
A cryogenic distillation process for producing oxygen comprising:
- (a) withdrawing gaseous oxygen at a product pressure of up to about 10 ATA from a latent heat exchanger;
- (b) supplying a fraction of air that has been cleaned and cooled to near its dewpoint at an elevated pressure that is at least approximately 21/2 times the oxygen product pressure to an elevated pressure rectification column;
- (c) rectifying the elevated pressure air to a liquid N.sub.2 over-head product and an oxygen enriched liquid bottom product;
- (d) refluxing the elevated pressure rectifier by indirect heat exchange in said latent heat exchanger with boiling pressurized liquid oxygen, whereby said gaseous oxygen at product pressure is obtained;
- (e) supplying said liquid nitrogen, said oxygen enriched liquid, plus a remaining fraction of air at a high pressure that is at least 2 ATA lower than said elevated pressure to a cryogenic distillation apparatus;
- (f) distilling said fluids from step (e) so as to obtain low pressure liquid oxygen;
- (g) pressurizing said low pressure liquid oxygen for use in step (d), while precluding the requirement for a mechanical gaseous oxygen compressor.
In a process for producing pressurized gaseous oxygen comprising:
- (a) supplying a major fraction of air at a high pressure and the remainder at an elevated pressure;
- (b) gasifying pressurized liquid oxygen by indirect heat exchange against condensing elevated pressure air;
- (c) supplying the high pressure air plus the liquid from step (b) to a subambient distillation process;
- (d) pumping liquid oxygen obtained from the subambient distillation process to the pressure required in step (b);
- the improvement comprising:
- (i) providing an elevated pressure rectification column;
- (ii) refluxing the elevated pressure rectifier by indirect heat exchange with said boiling pressurized liquid oxygen;
- (iii) withdrawing as product the resulting gaseous oxygen at a pressure up to about 10 ATA while precluding the requirement of mechanical compressing of the gaseous oxygen to that pressure;
- (iv) supplying said elevated pressure air to said elevated pressure column, whereby liquid nitrogen and oxygen enriched liquid are obtained;
- (v) using said liquid nitrogen as reflux in and further separating said oxygen enriched liquid in said subambient distillation process.
An apparatus for producing pressurized gaseous oxygen comprising:
- (a) a means designed for providing split supply pressure air, one fraction at a high pressure, and the remaining fraction at an elevated pressure which is at least 2 ATA higher than said high pressure;
- (b) an elevated pressure rectifier which rectifies the elevated pressure air fraction to liquid N.sub.2 and oxygen enriched liquid;
- (c) a means for pressurizing liquid oxygen;
- (d) a reflux condenser for the elevated pressure rectifier which gasifies the pressurized liquid oxygen;
- (e) a cryogenic distillation apparatus which is supplied the high pressure air fraction and the liquid N.sub.2 and oxygen enriched liquid from the elevated pressure rectifier and which produces the liquid oxygen which is pressurized in the means for pressurization;
- (f) a means designed for withdrawing said gasified pressurized liquid oxygen at a product pressure of up to about 10 ATA, said means including means for precluding a mechanical gaseous oxygen compressor.
Dependencies are inferred from the claim text.