Abstract: A method and composition for the removal of contaminants in a gas stream used in the contamination sensitive processes of photolithography and metrology are described. The synergistic effect of a combination of an electropositive metal component, a high silica zeolite, and a late transition metal compound effects removal or reduction of the contaminates in the gas which interfere with light transmittance to the ppb or ppt levels necessary for the gas to be suitable for these uses. The removal of neutral polar molecules, neutral polar aprotic molecules, protic and aprotic alkaline molecules, acidic polar species, and neutral non-polar aprotic molecules is accomplished with the claimed composition. Depending on the type of contaminant, the composition components are each varied from 10 to 80 parts by volume, with the total composition limited to 100 parts by volume.

Abstract: A method is described for rapid and economical activation and/or preconditioning of gas purification substrates by providing forced convection of the preconditioning or activating gas through the pores of the substrate. The gas is pumped into the substrate-containing vessel and raised to an elevated pressure, which is maintained for a short predetermined time, followed by venting of contents of the vessel. The vessel is again pressurized with the purging gas to an elevated level, and the elevated pressure is maintained for a short predetermined time, followed by venting of the vessel. This cycle is repeated as often as needed or desired. Activation and/or preconditioning can be accomplished in a much shorter time and with much less gas usage compared to diffusion preconditioning and activation processes. This process is particularly suited for preconditioning and activation of gas purifier substrates for decontamination of gases down to ≦1 ppm contaminants.

Abstract: A method and apparatus for the decontamination of fluid ammonia are described. Liquid or gaseous ammonia is purified of contaminants by passage through an adsorbent bed, the contaminants accumulating in the bed. A portion of the purified ammonia discharged from the bed is decomposed to hydrogen and nitrogen. The hydrogen is used to regenerate an adsorbent bed which has accumulated sufficient contaminants to reduce its ability to further decontaminate incoming ammonia satisfactorily. Preferably there are a plurality of interconnected adsorbent beds, with some being operated for ammonia decontamination while others are being regenerated, with their operations being reversed as needed to maintain a continual production of decontaminated ammonia from the plurality of beds. Computers or other controllers can be used to control such bed operations and interchanges. Internal production of hydrogen makes the system self-contained and no addition of hydrogen is needed.

Abstract: A gas purification system has at least one purifier in a purifier line with a gas supply inlet at one end and a process outlet at an opposite end for connection to a process tool using the purified gas. A vent line having a vent outlet is connected to the outlet end of the purifier. A control valve in the vent line controls connection of the purifier outlet to the vent outlet, and a control valve in the purifier line controls connection of the purifier outlet to the process outlet. A flow controller in the purifier line controls flow rate through the purifier. The system is controlled to provide an increased flow rate through the purifier and to connect the purifier outlet to the vent outlet on start up of the system, and then to connect the purifier outlet to the process outlet as soon as conditioning is complete.

Abstract: The present invention relates to an apparatus used for gas purification in a manner that allows for higher flow rates without an unacceptable increase in the pressure vessel diameter. The purifier contains inner and outer filter sleeves. Between the sleeves is contained a purification medium that allows for radial flow of the gas from the inner filter sleeve to the outer filter sleeve, via the purification medium, in order to be released from the purifier.

Abstract: A method is disclosed for providing a pure gas for use medical procedures in which the gas is contaminated with other gases during the procedure, and then separating the contaminants and recovering and reusing the decontaminated gas. The method is most advantageously used in medical imaging processes, such as magnetic resonance image (MRI), where hyperpolarized image enhancing noble gases, notably He3 or Xe129, are used for image enhancement in brain and lung imaging, and in which the contaminants are normally the exhalant gases from the imaged patient. The contaminated gas is passed through a series of drying and purification steps to remove the exhalant gases and separate the gas. The purified gas is then recovered and stored for reuse. This system prevents the loss of significant amounts of the image enhancing gases, which is important since key gases such as He3 and Xe129 are rare and expensive, and (especially He3) permanently lost once vented.

Abstract: A method and composition for the removal of contaminants in a gas stream used in the contamination sensitive processes of photolithography and metrology are described. The synergistic effect of a combination of an electropositive metal component, a high silica zeolite, and a late transition metal compound effects removal or reduction of the contaminates in the gas which interfere with light transmittance to the ppb or ppt levels necessary for the gas to be suitable for these uses. The removal of neutral polar molecules, neutral polar aprotic molecules, protic and aprotic alkaline molecules, acidic polar species, and neutral non-polar aprotic molecules is accomplished with the claimed composition. Depending on the type of contaminant, the composition components are each varied from 10 to 80 parts by volume, with the total composition limited to 100 parts by volume.

Abstract: A method for the decontamination of fluid (liquid or supercritical) carbon dioxide fluid, especially of hydrocarbon contaminants, down to ≦100 ppb concentration are described. The critical component is a high silica zeolite, preferably a high silica Y-type zeolite, ZSM-5 or a high silica mordenite, which in a variety of physical forms is capable of decontaminating such fluid CO2 to ≦100 ppb, ≦10-50 ppb, or ˜1 ppb, without being detrimentally affected by the supercritical operating environment. The high silica zeolite may be produced by the removal of alumina from a natural or synthetic zeolite while retaining the desirable zeolite structure, to a silica:alumina ratio of from 20-2000:1. Preferably the zeolite is disposed in separate quantities in at least two vessels, which operate alternately. A portion of the purified product from the operating vessel is directed to the other vessel and there used to remove accumulated contaminants from that vessel's zeolite.

Abstract: A gas purification apparatus has a housing with an inlet end having an inlet port for gas supply to an interior chamber, and an opposite, outlet end having an outlet port for exit of purified gas from the chamber. The housing is of generally cylindrical shape with a central axis, and the inlet and outlet ports are offset from the central axis towards a lower portion of the housing. A purification medium fills at least the majority of the chamber. The internal wall of the chamber is cylindrical along part of the length of the housing extending from the outlet end, and has a rounded or part-spherical inlet portion extending from the inlet port to the cylindrical part of the internal wall.

Abstract: A process and apparatus for the decontamination of gaseous contaminants (especially oxygen, carbon dioxide and water vapor) from hydride gases (including their lower alkyl analogs) down to ≦100 ppb contaminant concentration are described. The critical component is a high surface area metal oxide substrate with reduced metal active sites, which in various physical forms is capable of decontaminating such gases to ≦100 ppb, ≦50 ppb or ≦10 ppb level without being detrimentally affected by the hydride gases. The surface area of the substrate will be ≧100 m2/g, and preferably 200-800 m2/g. Oxides of various metals, especially manganese or molybdenum, can be used, and mixtures of integrated oxides, or one type of oxide coated on another, may be used. The substrate is preferably retained in a hydride-gas-resistant container which is installed in a gas supply line, such as to a gas- or vapor-deposition manufacturing unit.

Abstract: A gas recovery and reuse/recycle method is disclosed which can readily and economically recover valuable and/or environmentally hazardous gases from a manufacturing or chemical process and then return the gas to the process for reuse, and repeat this many times without significant contamination or degradation of the gas or the produced products. All gas transport, compression and storage equipment is designed and maintained so that it is non-contaminating to the process gas. Commonly the process gas will be a Group VIII gas, preferably He, Ne, Kr or Xe, or a gas which comprises a hazard to the ambient environment or beings therein, such as a carbon oxide gas, a halocarbon gas, an acid-precursor gas, a biologically hazardous gas, or a radioactive gas.

Abstract: A process, composition and apparatus for the removal of water from moist non-corrosive gases (such as those containing oxygen or CO.sub.2) down to .ltoreq.10-20 ppb water concentration are described. The dehydrating agent is an oxide or salt of an electropositive metal and has a surface area of at least 140 m.sup.2 /g, preferably 140-500 m.sup.2 /g, is compatible with the gas, and preferably is capable of dehydrating such gases to .ltoreq.1 ppb, preferably to as low as 500 ppt. The electropositive metal will be a Group 3b, 4b or lanthanide metal or vanadium. The preferred agent is a high surface area titania, zirconia, yttria or vanadia, with titania most preferred. The dehydrating agent can be in the form of a pelleted or granular bulk material or a coating on or within the pores of a substrate. The agent is retained in a simple container which is easily installed in a gas supply line for the gas, such as to a gas- or vapor-deposition manufacturing unit.

Abstract: A process and apparatus for the removal of water from corrosive halogen gases, particularly chlorine- or bromine-containing gases, down to .ltoreq.100 ppb water concentration are described. The critical component is a high silica zeolite, preferably high silica mordenite, which in a variety of physical forms is capable of dehydrating such gases to .ltoreq.100 ppb or .ltoreq.50 ppb without being detrimentally affected by the corrosive nature of the gases in the presence of water. The high silica zeolite is produced by the removal of alumina from a natural or synthetic zeolite while retaining the desirable zeolite structure, to a silica:alumina ratio of from 20-2000:1. Metal cations which may be depleted by the alumina removal may be replaced by solution impregnation. Halogen- or halide-containing gases, or those with equivalent corrosion properties, may be dehydrated without deterioration of the high silica zeolite.