The Boc Group, Inc.

Piotr J Sadkowski

Wenchang Ji

Atul M Athalye

Arthur I Shirley

Ravi Kumar Jain

Dongmin Shen

Robert James Ferrell

Steven J Finley

An ozone-oxygen gas stream produced by passing oxygen into an ozone generator is introduced into a membrane separation unit containing an ozone-permeable membrane. Ozone-enriched gas passes through the membrane and is recovered or it contacts a liquid or gas stream which contains ozone-reactive substances, thereby oxidizing the substances. The oxygen-enriched gas stream produced on the feed side of the membrane by permeation of ozone through the membrane is recycled to the ozone generator. Prior to being recycled, the oxygen-enriched stream may be purified to remove gaseous impurities which permeate through the membrane from the liquid or gas stream being treated.

Ozone purification process

Ammonia is purified by a membrane unit to concentrate ammonia and/or ammonia and moisture. Moisture is removed in a temperature-swing adsorption unit. The resultant product of such purification is then partially condensed to remove light components of other impurities and then partially vaporized to produce a pressurized ammonia product lean in heavy components. If the feed stream is processed through the membrane unit first, the permeate stream will be lean in such impurities as carbon dioxide, nitrogen and methane. Moisture and any carbon dioxide not removed in the membrane unit is then removed by the adsorption unit. The resultant stream produced by action of the membrane and adsorption units is then partially condensed to produce a liquid lean in light impurities. Such liquid is then partially vaporized within a product pressure vessel to produce ammonia vapor lean in heavy impurities and at a required operational pressure.

Method and apparatus for purifying ammonia

A method of processing semiconductor manufacturing exhaust gases for recovering at least hexafluoroethane in which a feed stream composed of the exhaust gases is passed through an adsorbent bed selected to adsorb oxygen, and also nitrogen if present, but not to appreciably adsorb the hexafluoroethane. As a result, a product stream, discharged from the adsorbent bed, has a higher concentration of hexafluoroethane than in the feed stream. In one embodiment, only a single adsorbent such as carbon molecular sieve is provided to adsorb the oxygen or a modified 4A zeolite could be used to adsorb both oxygen and nitrogen. When nitrogen is a potential constituent, layers of carbon molecular sieve and zeolite are provided to adsorb the oxygen and then the nitrogen, respectively. A third adsorbent, preferably 5A zeolite may be provided in addition to the foregoing two adsorbents to also adsorb any carbon tetrafluoride produced as a by-product.

Method of processing semiconductor manufacturing exhaust gases

An apparatus and method for recovering one or more components from the vapor feed in which the component is recovered from the vapor feed at a lower pressure within a lower pressure cold trap. Thereafter, a higher pressure cold trap is connected to the lower pressure cold trap and the component revaporizes in the lower pressure cold trap and resolidifies in the higher pressure cold trap. The higher pressure cold trap is then isolated and the component is allowed to thaw to build up a vapor pressure such that the component can be delivered for recovery at a high pressure. Two or more components having higher and lower boiling points can be recovered by low pressure cold traps set in series. Low pressure cold traps can be provided to operate in an out of phase relationship so that components are frozen on one set of lower pressure cold traps while being vaporized from the other set of cold traps. In the case of two component recovery, two high pressure cold traps are provided to allow two components to vaporize and thus develop a sufficient vapor pressure to be delivered at the requisite delivery pressure.

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Bridgewater, NJ, United States of America

Piotr J Sadkowski