Abstract: A process and apparatus for drying and removing carbon dioxide from a hydrogen and carbon monoxide containing synthesis gas by using adsorption vessels containing a first layer of 13 X-zeolite and a second layer of 3 A-zeolite in which the 3 A-zeolite precludes the formation of water of reaction when dry and carbon dioxide-free synthesis gas is used to regenerate the adsorption vessel countercurrent to feed flow of the synthesis gas.

Abstract: A faujasite aluminosilicate with a Si/Al ratio in the range of 1.05 to 1.26 having an non-uniform aluminum distribution, synthesized by crystallizing the zeolite from a mixture of alkali metal aluminate and alkali metal silicate wherein the mixture has an alkali metal oxide to silica ratio of at least 1.6 and a water to alkali metal oxide ratio of at least 37. The X-zeolite has utility as a gas separation adsorbent such as separating oxygen from nitrogen in air.

Abstract: A process for the low pressure chemical vapor deposition of silicon nitride from ammonia and a silane of the formula: (t-C.sub.4 H.sub.9 NH).sub.2 SiH.sub.2 provides improved properties of the resulting film for use in the semiconductor industry.

Abstract: A method for the dynamic cleaning of semiconductor fabrication equipment and particularly quartzware with a thermally activated source of fluorine, such as nitrogen trifluoride, at an elevated temperature, typically at the process operation temperature, wherein the cleaning is terminated prior to complete cleaning and removal of undesired substances allowing rapid restart of fabrication equipment so cleaned.

Abstract: A method for regenerating a nickel-based catalytic adsorbent without using hydrogen in each cycle. Depending upon the configuration of the adsorbent bed, one or more interim regenerations, comprising the steps of heating the bed, flowing ultra-high purity nitrogen without hydrogen through the bed to remove adsorbed species, followed by cooling the bed, can be used to prepare the adsorbent bed for removal of unwanted species contained in cyrogenically produced nitrogen in order to make UHP nitrogen.

Abstract: The present invention is directed to precise, accurate mixing two or more chemicals in a metered vessel to achieve a precise, accurate concentration of the chemicals. More particularly, the chemicals are mixed in a vessel having constricted vent tubes with level sensors to precisely and accurately determine the volume of chemical introduced into the vessel. Most specifically, the vessel is closed so that the introduction of the chemicals increases the vessel pressure to enhance the mixing of the chemicals, decrease turbulence and enhance the accuracy of the level sensors.

Abstract: A method for the dynamic cleaning of semiconductor fabrication equipment and particularly quartzware with thermally activated nitrogen trifluoride and a source of oxygen at elevated temperatures, typically at the process operation temperature, wherein the cleaning effluent is safely removed and cleaning by-products isolated or diluted to provide for efficient cleaning and rapid restarts of fabrication equipment so cleaned.

Abstract: In the purification of air to remove water and carbon dioxide and other contaminants prior to cryogenic separation of oxygen and nitrogen, water and carbon dioxide are adsorbed on a solid adsorbent and are periodically desorbed to regenerate the adsorbent by the passing of a heated regenerating gas such that the quantity of heat added to the regenerating gas to produce desorption is no more than 90 percent of the heat of adsorption liberated during the adsorption of the water and carbon dioxide. The process is applicable to removing other contaminants from other gas streams also.

Abstract: Temperature swing adsorption to remove CO.sub.2 from a gas stream is conducted using alumina to adsorb all the water and at least most of the carbon dioxide from the gas stream. Optionally a downstream zone of zeolite may be provided to remove further carbon dioxide and hydrocarbons.

Abstract: The molar ratio of hydrogen and carbon monoxide in synthesis gas is changed by partially condensing at least a portion of the feed gas and separating the partially condensed feed mixture by non-fractionating phase separation. Preferably, the partially condensed feed mixture is separated by a first phase separation into a first liquid stream and a first vapor stream; the first vapor stream is partially condensed and separated by a second phase separation into a second liquid stream and a second vapor stream; the second vapor stream is warmed and expanded to provide refrigeration and partial condensation; and the expanded partially condensed stream is separated by a third phase separation to provide a third liquid stream and a third vapor stream. The synthesis gas product is at least partially derived from the third liquid stream and a portion of the third vapor stream.

Abstract: The present invention is a method and apparatus for the dynamic cleaning of semiconductor fabrication equipment and particularly quartzware with thermally activated nitrogen trifluoride wherein the cleaning effluent is safely removed and cleaning by-products isolated or diluted to provide for efficient cleaning and rapid restarts of fabrication equipment so cleaned.

Abstract: Method and apparatus for maintaining even heat distribution to each of the tubes contained in a down-fired induced draft furnace by eliminating external atmosphere disturbances such as wind from influencing furnace operation. The top of the furnace is isolated from receiving ambient air except through a central path which controls both rate and direction of air flow.

Abstract: A process for the adsorption of at least carbon dioxide, water and oxides of nitrogen and preferably acetylene from a feed gas, comprises contacting the feed gas with an adsorbent mixture of a zeolite and an alumina. The process may be operated as a swing adsorption process comprising contacting the gas with the adsorbent at a first temperature and pressure to adsorb at least carbon dioxide, water and oxides of nitrogen therefrom and periodically regenerating the adsorbent by reducing the pressure and or increasing the temperature to which the adsorbent is exposed.

Abstract: The present invention is a method of selective adsorptively separating nitrogen from oxygen using a crystalline metallosilicate having a ZSM-2 structure with a Si/Al ratio less than 2.0 and a lithium cation exchange of at least 50%, wherein the composition has the chemical formula:M.sub.2/n O:X.sub.2 O.sub.3 :(2.0 to <4.0)SiO.sub.2wherein M=one or more metal cations having a valence of n, and X is selected from the group consisting of aluminum, gallium and boron, preferably aluminum. The method is conducted at a bed temperature in the range of approximately -100.degree. C. to 100.degree. C.

Abstract: The present invention is a process for very low temperature chemical vapor deposition of silicon dioxide, comprising the steps ofa) heating a substrate upon which silicon dioxide is to be deposited to a temperature in the range of approximately 150 to 500.degree. C. in a vacuum maintained at a pressure in the range of approximately 50 to 750 mTorr;b) introducing into said vacuum an organosilane containing feed and an oxygen containing feed, said organosilane containing feed consisting essentially of one or more compounds having the general formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently alkyl, alkenyl, alkynyl, or aryl, having C.sub.1 to C.sub.6, or R.sup.1 and R.sup.2 are combined to form an alkyl chain C.sub.x (R.sup.3).sub.2, where R.sup.3 is independently H, C.sub.x H.sub.2x+1, and x=1-6, and R.sup.4 is independently H, C.sub.y H.sub.2y+1 where y=1-6; andc) maintaining said temperature and vacuum thereby causing a thin film of silicon dioxide to deposit on the substrate.

Abstract: A process for pressure swing adsorption of oxygen from a gas mixture containing at least oxygen and nitrogen to recover an unadsorbed nitrogen enriched product from a plurality of parallel piped adsorbent beds undergoing adsorption, depressurization and repressurization wherein the improvement is conducting a pressure transfer from one bed to another from an intermediate point of the bed finishing adsorption to a point closer to the feed end of a bed that is repressurizing to improve productivity and recovery of nitrogen enriched gas in the process.

Abstract: Method and apparatus for removing trace levels of impurities from gases stored cryogenically in a storage vessel in liquid form by passing a vaporized portion of liquified gas from the storage vessel through a bed of adsorbent while using the liquified gas to cool the adsorbent. Vaporized gas resulting from cooling of the adsorbent with the stored liquified gas can be combined with the vapor withdrawn from the storage vessel prior to being passed through the bed of adsorbent. Liquified gas can be withdrawn from the storage vessel, vaporized and the vaporized gas combined with the vaporized gas from the storage vessel prior to being passed through the bed of adsorbent.

Abstract: A method for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane, comprising the steps of: compressing a gas stream containing a diluent gas and fluorochemicals to an elevated pressure; heating the gas stream containing a diluent gas and fluorochemicals to an elevated temperature sufficient to increase the flux of the permeate stream and to increase the selectivity of the membrane for the permeation of the diluent gas relative to the permeation of the fluorochemicals; contacting the gas stream with a membrane which is selectively more permeable to the diluent gas than the fluorochemicals to result in a permeate stream rich in the diluent gas and a retentate rich in fluorochemicals; contacting the gas stream with one or more additional membranes which are selectively more permeable to the diluent gas than the fluorochemicals to result in a second permeate stream rich in the diluent gas and a second retentate

Abstract: A method for the dynamic cleaning of semiconductor fabrication equipment and particularly quartzware with thermally activated diluted nitrogen trifluoride at elevated temperatures, typically at the process operation temperature, wherein the cleaning effluent is safely removed and cleaning by-products isolated or diluted to provide for efficient cleaning and rapid restarts of fabrication equipment so cleaned.

Abstract: The present invention is directed to two embodiments of a process for recycling an impure argon effluent from a silicon crystal growing furnace using cryogenics. The first embodiment uses cryogenic distillation techniques, and the second embodiment uses cryogenic adsorption, both of which use catalytic treatments and adsorption in conjunction with their cryogenic process steps to provide a pure argon recycle stream for a silicon crystal growth furnace.