Increased argon recovery from air distillation
OwnerDonald C. Ericksoninventor
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Abstract
Process and apparatus are disclosed for increasing argon recovery in conjunction with cryogenic distillation of air to high purity oxygen. The increased argon recovery is obtained by incorporating one or more latent heat exchangers in the flowsheet at strategic disclosed locations and between specific fluids. The invention is particularly advantageous in conjunction with LOXBOIL flowsheets, which otherwise lose O.sub.2 recovery when argon recovery is increased.
Claims19
In a process for producing high purity oxygen and by-product argon by distilling cooled and cleaned air in a distillation apparatus comprised of a high pressure (HP) rectifier and a low pressure (LP) column comprised of an argon stripping section, a nitrogen removal section, and an argon rectifying section, the improvement comprising:
- exchanging latent heat between the argon rectifying section and the nitrogen removal section so as to provide intermediate reflux to the former and intermediate reboil to an intermediate height of the latter.
In a cryogenic air distillation apparatus for producing high purity oxygen plus byproduct argon comprised of a high pressure (HP) rectifier and a low pressure (LP) column comprised of an argon stripping section, a nitrogen removal section, and an argon rectifying section, the improvement comprising:
- means for exchanging latent heat from an intermediate height of the argon rectifying section to an intermediate height of the nitrogen removal section.
A process for producing high purity oxygen and byproduct argon by distilling air in a distillation apparatus comprised of a high pressure (HP) rectifier and a low pressure (LP) column comprised of an argon stripping section a nitrogen removal section, and an argon rectifying section, wherein the improvement comprises:
- a. partially expanding liquid nitrogen from the HP rectifier overhead;
- b. evaporating said partially expanded liquid nitrogen by exchanging latent heat with argon rectifying section intermediate height vapor;
- c. refluxing the argon rectifier with the liquefied intermediate height vapor;
- and
- d. work expanding said evaporated partially expanded nitrogen.
Apparatus for producing oxygen and argon comprised of a low pressure column which includes a nitrogen removal section and an argon rectifying section wherein the improvement comprises means for increasing argon recovery comprised of (a) a first latent heat exchanger in which intermediate height liquid from the N.sub.2 removal section is evaporated and intermediate height vapor from the argon rectifier is condensed;
- and/or (b) a second latent heat exchanger in which intermediate vapor from the argon rectifier is condensed and liquid nitrogen is evaporated at an intermediate pressure and a work expander for said evaporated intermediate pressure nitrogen.
Dependencies are inferred from the claim text.