The Boc Group, Inc.

Neil Hogg

Joseph Straub

Mark Leskowicz

An air separation apparatus and method for producing a gaseous oxygen product at a delivery pressure. A, filtered, compressed and purified air stream is formed and preferably divided into first and second air streams. The air contained within the first air stream is separated by a low temperature rectification process operating in accordance with a Claude cycle to produce liquid oxygen in a lower pressure column with a double column air separation unit. A Claude expander expands at least a major portion of the air contained within the first air stream into the high pressure column. The second air stream is compressed and partially cooled and is then expanded with the performance of work which is in turn applied to the work of compression of the second air stream. Liquid oxygen is pumped from the lower pressure column to substantially the delivery pressure and is vaporized within a mixing column against the second air stream which is also introduced into the mixing column. A liquid stream composed of the liquid produced in the mixing column is then introduced into an intermediate location of the lower pressure column to add the refrigeration of the second air stream to the process.

Method and apparatus for producing oxygen

An air separation apparatus and method in which a high pressure gaseous product is produced as a liquid, pumped to a delivery pressure and then vaporized prior to its discharge as product. In order to accomplish the requisite vaporization, a subsidiary stream of incoming air is compressed by a booster compressor and then passed into indirect heat exchange with the pumped liquid in a falling film evaporator. The falling film evaporator maintains an essentially constant temperature difference between the air and falling film, formed of the pumped liquid. As a result, a very small temperature differences can be maintained as compared with the conventional use of a thermosyphon reboiler. As a result, less booster compression is required for the subsidiary air stream over a prior art plant.

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Summit, NJ, United States of America

Neil Hogg