The Boc Group, Inc.

Atul M Athalye

Piotr J Sadkowski

Arthur I Shirley

Rustam H Sethna

Wenchang Ji

Ravi Kumar Jain

Dongmin Shen

Michael K Sahm

Steven J Finley

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.

Multi-component recovery apparatus and method

A gas injection apparatus for injecting a gas into a liquid comprising a baffle plate, a re-circulation chamber, and a discharge nozzle. The discharge nozzle is oriented normally to the baffle plate so that a liquid stream composed of the liquid is directed against the baffle plate and produces an oppositely directed flow towards the outer peripheral edge of the baffle plate. The oppositely directed flow has a sheet-like turbulent flow regime located adjacent to the plate and a circulating flow regime located above the turbulent flow regime and bounded by a re-circulation chamber. The gas is mixed into the liquid so that smaller bubbles are entrained in the turbulent flow regime and are discharged with the liquid flowing in the turbulent flow regime from the outer peripheral edge of the baffle plate. Larger bubbles flow into the circulating flow regime to break up into smaller bubbles which are entrained in the turbulent flow regime swept out of the apparatus. The apparatus is particularly useful in a gold leaching process in which the gold slurry is thickened to produce clarified water. Oxygen is injected into the clarified water and thereafter, the clarified water is injected into a leaching tank.

Gas injection apparatus and method having application to gold leaching

An apparatus and method for dispersing a gas in a liquid and for increasing gas pressure of a gas from a supply pressure to a delivery pressure. A first pump pumps the liquid to produce a pressurized liquid stream. The gas is injected into the pressurized liquid stream through for instance, a piping tee. The gas injection produces a pressure drop within the gas and as a result, the first pump pumps the liquid stream so that it has a static pressure no greater than the injection pressure. A second pump pumps the resultant pressurized gas-liquid stream so that an outlet liquid stream is produced with the liquid having a greater head than that of the pressurized liquid stream and the gas having the increased delivery pressure.

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Chatham, NJ, United States of America

Atul M Athalye