Patents Represented by Attorney Wan Yee Cheung
  • Patent number: 6509194
    Abstract: A method and apparatus for determining ammoniacal species concentration in a gas sample. In one embodiment, trace concentration of ammonia in an air sample is determined by monitoring emission intensity from an excited radical species (NH*), which is produced in a reaction between ammonia and fluorine. The observed emission intensity is compared with calibration data obtained from previously analyzed gas samples containing ammonia. The method and apparatus can also be adapted to detect ammoniacal species concentration in other NH-containing gas samples.
    Type: Grant
    Filed: July 24, 2000
    Date of Patent: January 21, 2003
    Inventor: Barry Gelernt
  • Patent number: 6475349
    Abstract: A distillation column and method in which a plurality of beds of structured packing are provided within a column shell and are configured to contact liquid and vapor phases of the mixture to be distilled. At least one liquid redistributor is located between the beds of structured packing to redistribute the liquid of the liquid phase and an annular collector is located above the liquid distributor to direct liquid to the liquid distributor. The annular collector acs as a constriction to produce a central flow of the vapor phase which can result in decreased performance of overlying beds of structured packing. In order to overcome this potential problem, a truncated bed of structured packing is provided directly above the annular collector to promote a more uniform distribution of such central vapor flow in a transverse direction of the column shell.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: November 5, 2002
    Assignee: The BOC Group, Inc.
    Inventors: Kevin McKeigue, Nancy Christine Irwin
  • Patent number: 6464955
    Abstract: Partial oxidation of hydrocarbons to produce hydrogen and carbon monoxide is carried out by a fixed bed or a fluidized bed process which includes the steps of passing steam and/or carbon dioxide through a perovskite-type ceramic mixed conductor in an adsorption zone at an elevated temperature, thereby at least partially saturating the mixed conductor with oxygen and producing hydrogen and/or carbon monoxide, and subsequently contacting the hot, at least partially oxygen-saturated mixed conductor with a hydrocarbon in a partial oxidation reaction zone. During the partial oxidation reaction phase of the process, the sorbed oxygen reacts with the hydrocarbon, thereby producing hydrogen and carbon monoxide.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: October 15, 2002
    Assignee: The BOC Group, Inc.
    Inventors: Yongxian Zeng, Donald L. MacLean, Satish S. Tamhankar, Narayanan Ramprasad, Frank R. Fitch, Kirk Walton Limbach
  • Patent number: 6458334
    Abstract: A process for the partial oxidation of hydrocarbons, such as methane, to produce hydrogen and carbon monoxide is provided. The process is conducted by contacting a mixture of a hydrocarbon-containing gas and an oxygen-containing gas in the presence of a metal catalyst at high gas velocities and low reaction initiation temperatures. The metal catalyst is a transition metal selected from the group of nickel, cobalt, iron, platinum, palladium, iridium, rhenium, ruthenium, rhodium, osmium and combinations thereof supported on a ceria monolith. Less than 3% by volume of carbon dioxide is present in the product gas.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: October 1, 2002
    Assignee: The BOC Group, Inc.
    Inventors: Satish S. Tamhankar, Narayanan Ramprasad, YuDong Chen, Mark S. Tomczak
  • Patent number: 6449983
    Abstract: Liquefied natural gas is stored in an insulated tank, typically forming part of an ocean going tanker. Boiled off vapour is compressed in a compressor and at least partially condensed in a condenser. The resulting condensate is returned to the tank. The vapour is mixed with liquefied natural gas in a mixing chamber upstream of the compressor. The liquefied natural gas so mixed with the vapour in the mixing chamber is taken from the condensate or from the storage tank.
    Type: Grant
    Filed: March 8, 2001
    Date of Patent: September 17, 2002
    Assignee: The BOC Group, Inc.
    Inventor: Josef Pozivil
  • Patent number: 6439836
    Abstract: A cryogenic turbo-expander has a rotary shaft which carries a turbine wheel and carries or is operatively associated with an energy dissipating device and which extends axially through a sleeve. Two sets of bearings, which are housed by two races surrounding the shaft, are axially spaced from one another. Each race has an aperture therein extending from an outer to an inner surface thereof communicating with a lubricating oil passage extending from an outer surface to an inner surface of the sleeve. Both races are arranged so that spent lubricating oil can pass therefrom to a common drain passage. The cryogenic turbo-expander additionally includes a reservoir for lubricating oil communicating with the aperture in the first race via an intermittently-operable metering pump and with the second race via an intermittently operable metering pump.
    Type: Grant
    Filed: June 2, 2000
    Date of Patent: August 27, 2002
    Assignee: Cryostar-France SA
    Inventor: Josef Pozivil
  • Patent number: 6395139
    Abstract: There is provided a feed distributor for feeding liquid to a liquid distributor. The feed distributor has an elongated body sized to extend across the liquid distributor and an inlet defined in the one of the ends thereof. One or more passageways are provided within the body extending between the ends of the body. Each passageway has an elongated outlet configured to discharge the liquid across the liquid distributor. Each passageway has a taper configured to promote a constant liquid velocity within the passageway. As a result, a uniform liquid distribution of the liquid out of the elongated outlet and therefore to the liquid distributor are promoted.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: May 28, 2002
    Assignee: The BOC Group, Inc.
    Inventor: Richard W. Potthoff
  • Patent number: 6369398
    Abstract: A method of vacuum ultraviolet (VUV) lithography in which an irradiating wavelength is selected to be in a region of low absorption in air, e.g., one in the vicinity of a local minimum in an oxygen absorption spectrum. In one embodiment, a lithographic exposure wavelength is advantageously selected between 121.0 nm to 122.0 nm, preferably at about 121.6 nm, corresponding to an absorption window in the oxygen spectrum. This method relaxes the otherwise stringent vacuum and inert gas purge requirement imposed on a VUV lithographic tool.
    Type: Grant
    Filed: March 29, 1999
    Date of Patent: April 9, 2002
    Inventor: Barry Gelernt
  • Patent number: 6312651
    Abstract: Apparatus for recovering sulphur from a combustible gas stream comprising hydrogen sulphide is provided. The combustible gas stream, air and oxygen, or an oxygen-rich stream, are fed via a coaxial burner into an elongate furnace thereby creating a longitudinally-extending flame which has one or more relatively oxygen-rich, intense, combustion regions wherein hydrogen sulphide is combusted to form sulphur dioxide and one or more relatively oxygen-poor, endothermic, thermal dissociation regions. Residual hydrogen sulphide reacts with sulphur dioxide formed by the combustion to produce sulphur vapor. The apparatus includes a waste heat boiler to reduce the temperature of the furnace effluent and a condenser to remove sulphur therefrom. The furnace has an aspect ratio of about 8:1. The flame diverges from its root to occupy at its maximum cross-sectional area at least about 80% of the cross-sectional area of the furnace interior coplanar therewith.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: November 6, 2001
    Assignee: The BOC Group plc
    Inventors: Richard William Watson, Stephen Rhys Graville
  • Patent number: 6305191
    Abstract: A first stream of air is compressed in a main air compressor and a booster compressor is cooled at a first pressure by passage through a main heat exchanger. The cooled stream is introduced without further compression into the higher pressure column of a double rectification column including in addition to the column a lower pressure column and a condenser-reboiler. A second stream of compressed air is expanded from a second pressure in an expansion turbine with the performance of external work. The expanded second stream of air is introduced into the lower pressure column. An oxygen product, typically impure, is taken from the bottom region of the lower pressure column. The second pressure is less than the first pressure column. The second pressure is less than the first pressure, the second air stream being taken from intermediate the compressors.
    Type: Grant
    Filed: May 5, 2000
    Date of Patent: October 23, 2001
    Assignee: The BOC Group plc
    Inventor: Paul Higginbotham
  • Patent number: 6293126
    Abstract: A double column air separation method in which a first stream of compressed air is cooled by passage through a main heat exchanger from its warm end countercurrently to a nitrogen stream withdrawn from the top of a lower pressure rectification column. The first stream of compressed air flows from the main heat exchanger into a higher pressure rectification column through an inlet. A second stream of compressed air is also passed into the warm end of the main heat exchanger and is cooled therein. The second stream of compressed air passes out of heat exchange with the nitrogen stream at a temperature lower than the exit temperature therefrom of the first stream of compressed air and at least 5K lower than the bubble point temperature of air at the pressure prevailing at the inlet. A stream of oxygen-enriched liquid passes isenthalpically from the bottom of the higher pressure column to the lower pressure column.
    Type: Grant
    Filed: October 17, 2000
    Date of Patent: September 25, 2001
    Assignee: The BOC Group plc
    Inventor: Paul Higginbotham
  • Patent number: 6287535
    Abstract: A first combustible gas stream containing hydrogen sulphide is subjected to treatment in a first Claus plant including a first thermal Claus stage. Part of the hydrogen sulphide content of a second combustible gas stream containing hydrogen sulphide is burned in at least one further thermal Claus stage. The combustion in the further thermal Clause stage is supported by oxygen-enriched air having an oxygen mole fraction of at least about 0.25 or by oxygen. Resulting sulphur dioxide in the further thermal Clause stage reacts with residual hydrogen sulphide to form sulphur vapour which is condensed out of the effluent gas from the further thermal Claus stage to form a sulphur-depleted effluent gas stream. A first control signal is generated which is a function of the flow rate of the second gas. A second control signal which is a function of the hydrogen sulphide/sulphur dioxide mole ratio in the sulphur-depleted effluent stream is also generated.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: September 11, 2001
    Assignee: The BOC Group plc
    Inventor: Ronald Ludwig Schendel
  • Patent number: 6280819
    Abstract: The present invention provides a structured packing comprising a plurality of corrugated sheets and a plurality of flat, planar members alternating with and located between the sheets to inhibit turbulence in vapor ascending through the structured packing. The plurality of planar members are positioned so that at least lowermost transverse edges of the planar members and the corrugated sheets are situated at least proximal to one another as viewed when said structured packing is in use. Each of the planar members and the corrugated sheets has perforations sized to inhibit liquid and vapor flows but to allow pressure equalization. The planar members can be strip-like and positions at or near the top and bottom transverse edges of the corrugated sheets or can have the same length and width of the corrugated sheets. The size and number of perforations can be optimized for air separation applications.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: August 28, 2001
    Assignee: The BOC Group, Inc.
    Inventors: Kevin McKeigue, Ramachandran Krishnamurthy, Hendrik Adriaan Kooijman
  • Patent number: 6257019
    Abstract: Nitrogen is produced by separation of it from air. Nitrogen so separated is condensed. Most or all of the nitrogen is separated by rectification. At least some of the condensed nitrogen is employed as reflux in the rectification. The nitrogen is both separated and condensed at three or more different pressures.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: July 10, 2001
    Assignee: The BOC Group plc
    Inventors: John Douglas Oakey, Paul Higginbotham