Cryogenically producing oxygen-enriched liquid and/or gaseous oxygen from atmospheric air

Abstract

A system and method are disclosed for the production of oxygen-enriched liquid and purified gaseous oxygen from local atmospheric air. In one embodiment, the system includes an air mover for generating a local atmospheric air stream; a cryocooler including a cooling element thermally coupled to a condensing separator; a heat exchanger having a first path for receiving a cold gaseous exhaust stream from the condensing separator and a second path for chilling and removing readily-condensible contaminants from the local atmospheric air stream to form a purified gas mixture stream via heat transfer to the cold gaseous exhaust stream; and a receiver for the oxygen-enriched liquid that condenses from the purified gas mixture stream in the condensing separator, leaving the gaseous exhaust stream.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 60 / 579,276, filed Jun. 14, 2004.BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] The invention relates to cryogenic gas separation, and more particularly, to a system and method for cryogenically producing oxygen-enriched liquid and / or purified gaseous oxygen from atmospheric air, on demand, at or near the point of use. [0004] 2. Related Art [0005] A growing number of aging persons require oxygen therapy, typically in the range of 1-5 liters per minute of purified oxygen introduced to their breathing air to compensate for reduced lung capacity. Many of these people remain mobile and moderately active for many months or years while requiring such therapy. Presently, most of these people are served in their homes by use of an oxygen concentrator, which pressurizes the air and preferentially passes oxygen through a separator (e.g., membrane or pressure-swing absorber), delivering purities in the ...

AI Technical Summary

Benefits of technology

[0013] A third aspect of the invention relates to a method for producing oxygen-enriched liquid from local atmospheric air, the method comprising the steps of: forming an input stream of the local atmospheric air; using cold exhaust from a closed-cycle cryogenic cooler to remove readily-condensible contaminants from the input stream to form a purified gas stream; and cryogenically cooling the purified gas stream with a closed-cycle refrigerator to condense oxygen to form the oxygen-enriched liquid.

[0014] A fourth aspect of the invention is directed to a system for producing purified gaseous oxygen from local atmospheric air, the system comprising: an air mover

Problems solved by technology

These bulky, heavy tanks must be pulled by the individual on wheeled carts, which is a difficult and awkward process, especially for elderly people with breathing difficulties.

Present LOX therapy is achieved only at much higher cost than typical gaseous oxygen therapies.

LOX therapy is also unavailable to many people, insured or not, because such treatment requires the regular, periodic delivery of large, insulated dewar tanks of LOX to the patients home, solely to allow refilling of the lightweight mobile supply.

Accordingly, a concentrator is still used for stationary support because the cost of delivered LOX is too high for stationary use.

Consequently, LOX therapy today is restricted to a minority of relatively wealthy individuals even though many more would benefit by its advantages in comfort and effectiveness if a cost-effective means to provide it can be developed.

A disadvantage of this approach, however, is that a standard concentrator is still required, which adds complexity and cost.

However, these plants are vastly too large because they necessarily employ industrial-scale structure that is impractical for home production of oxygen-enriched liquid in individual-use quantities.

In addition, older large mass production plants use reversing heat exchangers, but always require pre-separation of water vapor (H2O) and carbon dioxide (CO2) to delay the requirement for reversing with the required high internal volume and consequent reversing losses.

Furthermore, efficiency is considered tantamount to these systems, which necessitates many features that add costs to the systems, making them impractical for a mass market.

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