Natural Gas From Nitrogen Patents (Class 62/927)
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Patent number: 11628451Abstract: Methods and systems for separating liquid components are disclosed. A vessel is provided containing a solids conveyance device. At least a first portion of the vessel acts as an indirect-contact heat exchanger and a second portion of the vessel contains a filter. A process liquid stream, containing a first component and a second component, is passed into the first portion of the vessel. A portion of the second component is frozen and entrained in the first portion of the vessel into the process liquid stream, resulting in a process slurry stream. The process slurry stream is passed into a second portion of the vessel by the solids conveyance device. The process slurry stream is separated into a solid product stream and a primary liquid product stream by passing the primary liquid product stream through the filter and out of the vessel while separately removing the solid product stream out of the vessel.Type: GrantFiled: March 25, 2019Date of Patent: April 18, 2023Assignee: Sustainable Energy Solutions, LLCInventors: Larry Baxter, Stephanie Burt
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Patent number: 9016088Abstract: A system and method for removing nitrogen and producing liquefied natural gas (“LNG”) from methane without the need for external refrigeration. The invention also relates to a system and method for removing nitrogen from methane and for producing liquefied nitrogen in addition to LNG. The system and method of the invention are particularly suitable for use in recovering and processing comparatively small volumes of methane from coal mines or from flash gas captured at an LNG loading site.Type: GrantFiled: October 29, 2010Date of Patent: April 28, 2015Assignee: Butts Propertties, Ltd.Inventor: Rayburn C. Butts
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Patent number: 9003829Abstract: The invention relates to a method for the separation of a hydrocarbon-rich, nitrogen-containing feed fraction (1, 101), preferably natural gas, wherein the feed fraction (1, 101) is at least in part liquefied (E1, E2) and divided by rectification (T1) into a nitrogen-enriched fraction (14, 110) and a hydrocarbon-rich, nitrogen-depleted fraction (11, 111) and wherein, in the upper region of the rectification (T1), a nitrogen-enriched stream (14) is taken off, cooled (E3) and applied (20) at least in part to the rectification (T1) as reflux and/or the nitrogen-enriched fraction (110) is cooled and partially condensed (E3), applied at least in part to the rectification (T1) as reflux (115) and the remaining stream (116) of the nitrogen-enriched fraction (110) is subjected to a double-column process (T3).Type: GrantFiled: May 11, 2011Date of Patent: April 14, 2015Assignee: Linde AktiengesellschaftInventors: Heinz Bauer, Martin Gwinner, Daniel Garthe
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Patent number: 8715390Abstract: A method is described for separating off trace components from a fraction (1) containing at least nitrogen and helium, wherein this fraction is partially condensed (E) before enrichment of the helium. The partially condensed fraction (2) is fed at least in part to at least one separation column (T) and separated therein into a helium-rich gas fraction (6) and a nitrogen-rich liquid fraction which also contains the unwanted trace components (5).Type: GrantFiled: February 7, 2012Date of Patent: May 6, 2014Assignee: Linde AktiengesellschaftInventors: Hans Schmidt, Klaus Ohlig, Ulrich Lindemann, Peter Re, Hung Nguyen
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Patent number: 8627681Abstract: A process for recovery of natural gas liquids is disclosed, the process including: fractionating a gas stream comprising nitrogen, methane, ethane, and propane and other C3+ hydrocarbons into at least two fractions including a light fraction comprising nitrogen, methane, ethane, and propane, and a heavy fraction comprising propane and other C3+ hydrocarbons; separating the light fraction into at least two fractions including a nitrogen-enriched fraction and a nitrogen-depleted fraction in a first separator; separating the nitrogen-depleted fraction into a propane-enriched fraction and a propane-depleted fraction in a second separator; feeding at least a portion of the propane-enriched fraction to the fractionating as a reflux; recycling at least a portion of the propane-depleted fraction to the first separator. In some embodiments, the nitrogen-enriched fraction may be separated in a nitrogen removal unit to produce a nitrogen-depleted natural gas stream and a nitrogen-enriched natural gas stream.Type: GrantFiled: March 4, 2009Date of Patent: January 14, 2014Assignee: Lummus Technology Inc.Inventor: Michael Malsam
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Publication number: 20120036890Abstract: Methods and systems for removing nitrogen from a natural gas feed stream. The systems and methods generally include a heat exchange unit, a separation unit, and a liquid methane pump unit, where the separation unit produces a liquid methane bottoms stream and a gaseous overhead stream enriched in nitrogen and the liquid methane pump unit compresses the liquid methane bottoms stream and then pumps the stream through the heat exchange unit to cool a natural gas feed stream. In some embodiments the liquid methane pump unit is a sleeve bearing type unit. Beneficially, the disclosed systems and methods incorporate high head pumps for liquid methane compression instead of vaporizing the liquid methane and compressing it in a gaseous compression units that are typically used for this purpose, saving space, materials, and power.Type: ApplicationFiled: March 8, 2010Publication date: February 16, 2012Applicant: Exxonmobil Upstream Research CompanyInventors: Edward L Kimble, Peter C Rasmussen
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Patent number: 7628035Abstract: In this method, the LNG stream is cooled using a refrigerating fluid in a first heat-exchanger. The refrigerating fluid is subjected to a second semi-open refrigeration cycle which is independent of the first cycle. The method comprises a step for introducing the stream of sub-cooled LNG into a distillation column and a step for recovering a stream of gas at the top of the column. The second refrigeration cycle comprises a step for forming a stream of refrigerating fluid from a portion of the top stream of gas, a step for compressing the stream of refrigerating fluid to a high pressure, then a step for expanding a portion of the stream of compressed refrigerating fluid in order to form a substantially liquid sub-cooling stream. The substantially liquid stream is evaporated in the first heat-exchanger.Type: GrantFiled: October 9, 2006Date of Patent: December 8, 2009Assignee: Technip FranceInventor: Henri Paradowski
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Patent number: 7520143Abstract: Nitrogen is removed from a liquefied natural gas feed (41) by a two stage separation in which the liquefied natural gas (41) is first fractionated (23) to provide a first nitrogen-enriched overhead vapour stream (46) and a nitrogen-containing bottoms liquid stream (19) and then at least a portion of said bottoms liquid stream (19) is fractionated (25) to provide a second nitrogen-enriched overhead vapour stream (36) that is of lower purity than said first overhead vapour stream (46) and a purified liquefied natural gas stream (50). The first fractionation is conducted in a distillation column (23) refluxed (45) with nitrogen overhead (43) condensed in a condenser (24) located in a flash drum (25) in which the second fractionation is conducted. The second nitrogen-enriched overhead vapour stream (36) provides fuel gas for use in the natural gas liquefaction plant.Type: GrantFiled: April 21, 2006Date of Patent: April 21, 2009Assignee: Air Products and Chemicals, Inc.Inventor: Christopher Geoffrey Spilsbury
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Patent number: 7373790Abstract: Nitrogen is rejected from a pressurized feed gas stream comprising methane and nitrogen by cooling the feed gas stream in a main heat exchanger and rectifying the cooled feed gas stream in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure column in heat exchange relationship with the lower pressure column. A pump withdraws a methane product stream from the column. The methane product stream is pressurized by the pump and is vaporized in the main heat exchanger. The pressurized feed gas stream is expanded with the performance of external work in an expansion turbine 6 upstream of the main heat exchanger.Type: GrantFiled: June 14, 2006Date of Patent: May 20, 2008Assignee: The BOC Group, plcInventors: Stephen R. Clare, John D. Oakey
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Patent number: 7234322Abstract: Natural gas liquefaction system employing an enhanced nitrogen removal system capable of removing nitrogen from a relatively warm natural gas stream.Type: GrantFiled: February 24, 2004Date of Patent: June 26, 2007Assignee: ConocoPhillips CompanyInventors: Paul R. Hahn, Philip D. Ritchie, Jame Yao, Rong-Jwyn Lee, Anthony P. Eaton, William R. Low
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Patent number: 7127915Abstract: Nitrogen is rejected from a pressurised feed gas stream comprising methane and nitrogen by cooling the feed gas stream in a main heat exchanger 10 and rectifying the cooled feed gas stream in a double rectification column 20 comprising a higher pressure rectification column 22, a lower pressure rectification column 24, and a condenser-reboiler 25 placing the higher pressure column 22 in heat exchange relationship with the lower pressure column 24. A pump 50 withdraws a methane product stream from the column 24. The methane product stream is pressurised by the pump 50 and is vaporised in the main heat exchanger 10. The pressurised feed gas stream is expanded with the performance of external work in an expansion turbine 6 upstream of the main heat exchanger 10.Type: GrantFiled: September 3, 2003Date of Patent: October 31, 2006Assignee: The BOC Group plcInventors: Stephen Roger Clare, John Douglas Oakey
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Patent number: 7059152Abstract: Nitrogen is rejected from a feed natural gas stream comprising methane and nitrogen so as to form a primary methane product. The mole fraction of nitrogen in the feed natural gas increases over a period of time. The feed natural gas stream is cooled in a main heat exchanger and is rectified in a double rectification column. A primary product methane stream and a secondary nitrogen-enriched product stream are withdrawn from the rectification column. The secondary nitrogen-enriched product stream has a mole fraction of methane at or above a chosen minimum value when the said mole fraction of nitrogen is at a minimum. When the said mole fraction of nitrogen rises to a value at which the mole fraction of methane in the secondary nitrogen-enriched product stream falls below the chosen minimum, a part of the feed gas is introduced through conduit into the secondary nitrogen-enriched product stream so as to restore its mole fraction of methane to the chosen minimum value or a value thereabove.Type: GrantFiled: November 5, 2003Date of Patent: June 13, 2006Assignee: The BOC Group plcInventors: John Douglas Oakey, Brian Morice Davies
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Patent number: 6978638Abstract: Method for the rejection of nitrogen from condensed natural gas which comprises (a) introducing the condensed natural gas into a distillation column at a first location therein, withdrawing a nitrogen-enriched overhead vapor stream from the distillation column, and withdrawing a purified liquefied natural gas stream from the bottom of the column; (b) introducing a cold reflux stream into the distillation column at a second location above the first location, wherein the refrigeration to provide the cold reflux stream is obtained by compressing and work expanding a refrigerant stream comprising nitrogen; and (c) either (1) cooling the purified liquefied natural gas stream or cooling the condensed natural gas stream or (2) cooling both the purified liquefied natural gas stream and the condensed natural gas stream, wherein refrigeration for (1) or (2) is obtained by compressing and work expanding the refrigerant stream comprising nitrogen.Type: GrantFiled: May 22, 2003Date of Patent: December 27, 2005Assignee: Air Products and Chemicals, Inc.Inventors: Adam Adrian Brostow, Mark Julian Roberts, Christopher Geoffrey Spilsbury
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Patent number: 6837071Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas is separated in a double rectification column comprising a higher pressure rectification column 14, a lower pressure rectification column 16, and a condenser-reboiler 18. Product methane is withdrawn from the column 16 by a pump 42 and is vaporised. A flow of gas is recycled from the column 16 to the column 14, being warmed in main heat exchanger 4. A first part of the warmed recycle gas being compressed in compressor 48 to a first pressure and introduced into the higher pressure rectification column 14. A second part of the warmed recycle gas is compressed in the compressor 48 and condensed in a second condenser-reboiler associated with an intermediate main exchange region of the lower pressure column 16 and is returned to the higher pressure rectification column 14.Type: GrantFiled: July 1, 2003Date of Patent: January 4, 2005Assignee: The BOC Group plcInventor: John Douglas Oakey
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Publication number: 20040231359Abstract: Method for the rejection of nitrogen from condensed natural gas which comprises (a) introducing the condensed natural gas into a distillation column at a first location therein, withdrawing a nitrogen-enriched overhead vapor stream from the distillation column, and withdrawing a purified liquefied natural gas stream from the bottom of the column; (b) introducing a cold reflux stream into the distillation column at a second location above the first location, wherein the refrigeration to provide the cold reflux stream is obtained by compressing and work expanding a refrigerant stream comprising nitrogen; and (c) either (1) cooling the purified liquefied natural gas stream or cooling the condensed natural gas stream or (2) cooling both the purified liquefied natural gas stream and the condensed natural gas stream, wherein refrigeration for (1) or (2) is obtained by compressing and work expanding the refrigerant stream comprising nitrogen.Type: ApplicationFiled: May 22, 2003Publication date: November 25, 2004Inventors: Adam Adrian Brostow, Mark Julian Roberts, Christopher Geoffrey Spilsbury
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Publication number: 20040182109Abstract: Nitrogen is rejected from a feed natural gas stream comprising methane and nitrogen so as to form a primary methane product. The mole fraction of nitrogen in the feed natural gas increases over a period of time. The feed natural gas stream is cooled in a main heat exchanger and is rectified in a double rectification column. A primary product methane stream and a secondary nitrogen-enriched product stream are withdrawn from the rectification column. The secondary nitrogen-enriched product stream has a mole fraction of methane at or above a chosen minimum value when the said mole fraction of nitrogen is at a minimum. When the said mole fraction of nitrogen rises to a value at which the mole fraction of methane in the secondary nitrogen-enriched product stream falls below the chosen minimum, a part of the feed gas is introduced through conduit into the secondary nitrogen-enriched product stream so as to restore its mole fraction of methane to the chosen minimum value or a value thereabove.Type: ApplicationFiled: November 5, 2003Publication date: September 23, 2004Inventors: John Douglas Oakey, Brian Morice Davies
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Patent number: 6758060Abstract: Substantially all the nitrogen is removed from natural gas during the production of LNG, without producing mixed nitrogen/methane streams needing recycle and further processing, or requiring compression for burning as fuel, by operating both the high pressure and the low pressure multistage distillation towers of a two column cryogenic nitrogen rejection unit to produce acceptable liquefied natural gas as tower bottom products, while the low pressure tower is further operated to produce as an overhead a gas steam containing no more than about 1% methane for safe venting to the atmosphere.Type: GrantFiled: February 14, 2003Date of Patent: July 6, 2004Assignee: Chart Inc.Inventor: John V. O'Brien
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Publication number: 20040103687Abstract: Nitrogen is rejected from a pressurised feed gas stream comprising methane and nitrogen by cooling the feed gas stream in a main heat exchanger 10 and rectifying the cooled feed gas stream in a double rectification column 20 comprising a higher pressure rectification column 22, a lower pressure rectification column 24, and a condenser-reboiler 25 placing the higher pressure column 22 in heat exchange relationship with the lower pressure column 24. A pump 50 withdraws a methane product stream from the column 24. The methane product stream is pressurised by the pump 50 and is vaporised in the main heat exchanger 10. The pressurised feed gas stream is expanded with the performance of external work in an expansion turbine 6 upstream of the main heat exchanger 10.Type: ApplicationFiled: September 3, 2003Publication date: June 3, 2004Inventors: Stephen Roger Clare, John Douglas Oakey
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Patent number: 6637239Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas stream is cooled in a main heat exchanger and is rectified in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in heat exchange relationship with the lower pressure rectification column. At least part of the feed gas stream is expanded into the higher pressure rectification column through an expansion valve, the feed gas stream being partially liquefied upstream of the double rectification column. Over a period of time the mole fraction of nitrogen in the feed gas mixture increases. At a suitable increased nitrogen mole fraction, operation of a second double rectification column in parallel with the first double rectification column is commenced.Type: GrantFiled: July 10, 2002Date of Patent: October 28, 2003Assignee: The BOC Group plcInventor: John Douglas Oakey
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Publication number: 20030177786Abstract: Substantially all the nitrogen is removed from natural gas during the production of LNG, without producing mixed nitrogen/methane streams needing recycle and further processing, or requiring compression for burning as fuel, by operating both the high pressure and the low pressure multistage distillation towers of a two column cryogenic nitrogen rejection unit to produce acceptable liquefied natural gas as tower bottom products, while the low pressure tower is further operated to produce as an overhead a gas steam containing no more than about 1% methane for safe venting to the atmosphere.Type: ApplicationFiled: February 14, 2003Publication date: September 25, 2003Inventor: John V. O'Brien
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Patent number: 6609393Abstract: A method of forming a methane product by rejecting nitrogen from a feed gas stream comprising methane and nitrogen is disclosed. After being cooled in a main heat exchanger, the feed gas stream is rectified in a double rectification column comprising a higher pressure column and a lower pressure column. A gas flow is recycled from the lower pressure column to the higher pressure column. Part of the recycle flow is compressed in a compressor, cooled, liquefied in a condenser-reboiler and introduced into the higher pressure column. Another part of the recycle flow is also compressed in the compressor, cooled, liquefied in the main heat exchanger or by expansion, and introduced into the double rectification column in liquid state. At least part of the cooling of both parts of the recycle gas is performed in the main heat exchanger. A liquid methane product is withdrawn from the lower pressure column.Type: GrantFiled: May 9, 2002Date of Patent: August 26, 2003Assignee: The BOC Group plcInventor: John Douglas Oakey
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Patent number: 6584803Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas stream is cooled in a main heat exchanger and rectified in a double rectification column comprising a higher pressure column, a lower pressure column and a condenser-reboiler placing the higher and lower pressure rectification columns in heat exchange relationship with each other. At least part of the feed gas stream is expanded through a valve into the higher pressure rectification column and the feed gas stream is partially liquefied upstream of the double rectification column. Over a period of time, the mole fraction of nitrogen in the feed gas stream may increase. The operating pressure of the lower pressure rectification column is periodically increased in response to increases in the mole fraction of nitrogen. A back pressure valve may be periodically adjusted to effect the increase in pressure.Type: GrantFiled: July 10, 2002Date of Patent: July 1, 2003Assignee: The BOC Group plcInventor: John Douglas Oakey
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Publication number: 20030029191Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas stream is cooled in a main heat exchanger and is rectified in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure rectification column in heat exchange relationship with the lower pressure rectification column. At least part of the feed gas stream is expanded into the higher pressure rectification column through an expansion valve, the feed gas stream being partially liquefied upstream of the double rectification column. Over a period of time the mole fraction of nitrogen in the feed gas mixture increases. At a suitable increased nitrogen mole fraction, operation of a second double rectification column in parallel with the first double rectification column is commenced.Type: ApplicationFiled: July 10, 2002Publication date: February 13, 2003Inventor: John Douglas Oakey
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Publication number: 20030019241Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas stream is cooled in a main heat exchanger and rectified in a double rectification column comprising a higher pressure column, a lower pressure column and a condenser-reboiler placing the higher and lower pressure rectification columns in heat exchange relationship with each other. At least part of the feed gas stream is expanded through a valve into the higher pressure rectification column and the feed gas stream is partially liquefied upstream of the double rectification column. Over a period of time, the mole fraction of nitrogen in the feed gas stream may increase. The operating pressure of the lower pressure rectification column is periodically increased in response to increases in the mole fraction of nitrogen. A back pressure valve may be periodically adjusted to effect the increase in pressure.Type: ApplicationFiled: July 10, 2002Publication date: January 30, 2003Inventor: John Douglas Oakey
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Publication number: 20020194866Abstract: A method of forming a methane product by rejecting nitrogen from a feed gas stream comprising methane and nitrogen is disclosed. After being cooled in a main heat exchanger, the feed gas stream is rectified in a double rectification column comprising a higher pressure column and a lower pressure column. A gas flow is recycled from the lower pressure column to the higher pressure column. Part of the recycle flow is compressed in a compressor, cooled, liquefied in a condenser-reboiler and introduced into the higher pressure column. Another part of the recycle flow is also compressed in the compressor, cooled, liquefied in the main heat exchanger or by expansion, and introduced into the double rectification column in liquid state. At least part of the cooling of both parts of the recycle gas is performed in the main heat exchanger. A liquid methane product is withdrawn from the lower pressure column.Type: ApplicationFiled: May 9, 2002Publication date: December 26, 2002Inventor: John Douglas Oakey
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Patent number: 6449984Abstract: A process for liquefaction of and nitrogen extraction from natural gas, an installation for implementation of the process, and gases obtained by this process. In the process, a first top fraction is cooled and liquefied, separated into a second top fraction which is relatively volatile and which provides gaseous nitrogen, and into a second bottom fraction which is withdrawn. The first bottom fraction is cooled in order to provide liquefied natural gas essentially free nitrogen.Type: GrantFiled: October 2, 2001Date of Patent: September 17, 2002Assignee: TechnipInventor: Henri Paradowski
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Patent number: 6425267Abstract: A process for treating natural gas or other methane-rich gas to remove excess nitrogen. The invention relies on membrane separation using methane-selective membranes, but does not require the membranes to be operated at very low temperatures. We have found that, by using a two-step membrane system design, and controlling the operating pressures for the membrane steps within certain ranges, the capital and operating costs of the process can be kept within economically acceptable limits.Type: GrantFiled: July 27, 2001Date of Patent: July 30, 2002Assignee: Membrane Technology and Research, Inc.Inventors: Richard W. Baker, Kaaeid A. Lokhandwala, Johannes G. Wijmans, Andre R. Da Costa
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Patent number: 6164088Abstract: A method for recovering a condensable gas from a mixed gas uses a condensable gas recovering apparatus. The apparatus comprises a compressor for compressing a mixed gas comprising a condensable gas and an incondensable gas, a mixed gas separator including a cooler and an adsorbent that adsorbs the incondensable gas, and a vacuum exhauster. The method comprises the steps of introducing the mixed gas highly compressed by the compressor into the mixed gas separator, liquefying and recovering the condensable gas by cooling the mixed gas separator with the cooler while the adsorbent adsorbs the incondensable gas contained in the mixed gas in a high pressure state, and exhausting the incondensable gas from the adsorbent in a low pressure state where the gas in the mixed gas separator has been exhausted by the vacuum exhauster. Therefore, recovery of the condensable gas is carried out with high reliability, and mixing of a large quantity of the condensable gas into the incondensable gas is easily prevented.Type: GrantFiled: December 9, 1998Date of Patent: December 26, 2000Assignee: Mitsubishi Denki Kaishushiki KaishaInventors: Tetsuo Moriguchi, Suenobu Hamano
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Patent number: 6116051Abstract: A technique is set forth to reduce the heat requirement of conventional distillation processes which separate feed mixtures containing three or more components. The technique provides a great deal of flexibility in adjusting the temperatures of the required utilities including a scenario where the heat requirement is reduced without a need for additional higher temperature (and more costly) heat utility. In this technique, when a liquid bottoms stream (or gaseous overhead stream) containing two or more components is sent from an earlier column to a subsequent column, then a return vapor (or liquid) stream is implemented between the same locations in the two columns.Type: GrantFiled: May 25, 1999Date of Patent: September 12, 2000Assignee: Air Products and Chemicals, Inc.Inventors: Rakesh Agrawal, Zbigniew Tadeusz Fidkowski
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Patent number: 5970742Abstract: The present invention teaches an efficient and easier to operate distillation embodiment to separate mixtures containing three or more components into streams enriched in one of the components. In this invention, from one end of an earlier distillation column, a liquid or a vapor stream containing two or more components is sent to a subsequent column, then a return vapor or a liquid stream is implemented between the same locations of the two columns. This establishes a two-way communication between one end of the earlier distillation column and the subsequent distillation column. From the other end of the earlier distillation column, a vapor or a liquid stream is eventually fed to another location of the subsequent distillation column; no return stream is implemented between the same locations of the two columns. This establishes the one-way communication between the other end of the earlier distillation column and the subsequent distillation column.Type: GrantFiled: April 8, 1998Date of Patent: October 26, 1999Assignee: Air Products and Chemicals, Inc.Inventors: Rakesh Agrawal, Zbigniew Fidkowski
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Patent number: 5953936Abstract: A technique is set forth to reduce the heat requirement of conventional distillation processes which separate feed mixtures containing three or more components. The technique provides a great deal of flexibility in adjusting the temperatures of the required utilities including a scenario where the heat requirement is reduced without a need for additional higher temperature (and more costly) heat utility. In this technique, when a liquid bottoms stream (or gaseous overhead stream) containing two or more components is sent from an earlier column to a subsequent column, then a return vapor (or liquid) stream is implemented between the same locations in the two columns.Type: GrantFiled: October 28, 1997Date of Patent: September 21, 1999Assignee: Air Products and Chemicals, Inc.Inventors: Rakesh Agrawal, Zbigniew Tadeusz Fidkowski
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Patent number: 5842357Abstract: A process for concentrating and recovering methane and carbon dioxide from landfill gas includes absorption of commonly occurring pollutants using a reduced amount of carbon dioxide absorbent which itself may be an in situ derived and recoverable constituent. Separated methane may be concentrated into a high heating value fuel, and a highly pure food-grade carbon dioxide product may also be recovered. Process streams may be used to provide fuel for compression and refrigeration and/or to regenerate carbon dioxide absorbent.Type: GrantFiled: October 28, 1997Date of Patent: December 1, 1998Assignee: Acrion Technologies, Inc.Inventors: Lawrence A. Siwajek, W. Jeffrey Cook, William R. Brown
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Patent number: 5802871Abstract: Nitrogen is removed from a pressurized feed gas mixture containing nitrogen and methane by cooling, partial condensation, and rectification in one or more dephlegmators. Autorefrigeration is provided by pressure letdown of selected process streams and external refrigeration is not required.Type: GrantFiled: October 16, 1997Date of Patent: September 8, 1998Assignee: Air Products and Chemicals, Inc.Inventors: Lee Jarvis Howard, Howard Charles Rowles
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Patent number: 5692395Abstract: A fluid mixture is separated by distillation in a two column system in which the feed is prefractionated in a first column having at least one separation stage above the feed and the prefractionator bottoms provides feed to a second column operating at a lower pressure. Cooling for condensing the overhead vapor of the first column is provided by indirect heat exchange with a flashed portion of the feed or with an intermediate fluid obtained from the second column. The two-column system is readily combined with a high pressure column in a three-column distillation system for separating air which is particularly useful for integration with a gasification combined cycle combustion turbine system. Optionally, three nitrogen products can be produced at three different pressures.Type: GrantFiled: May 2, 1996Date of Patent: December 2, 1997Inventors: Rakesh Agrawal, Jianguo Xu
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Patent number: 5647227Abstract: A membrane separation process combined with a cryogenic separation process for treating a gas stream containing methane, nitrogen and at least one other component. The membrane separation process works by preferentially permeating methane and the other component and rejecting nitrogen. The process is particularly useful in removing components such as water, carbon dioxide or C.sub.3+ hydrocarbons that might otherwise freeze and plug the cryogenic equipment.Type: GrantFiled: February 29, 1996Date of Patent: July 15, 1997Assignee: Membrane Technology and Research, Inc.Inventor: Kaaeid Lokhandwala
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Patent number: 5638698Abstract: A system for processing nitrogen-containing effluent from an industrial process wherein the effluent is cooled and liquid nitrogen is added directly to the cooled effluent. The direct contact and heat exchange produces gaseous nitrogen and liquid organics which are both used to cool the effluent and are subsequently recovered.Type: GrantFiled: August 22, 1996Date of Patent: June 17, 1997Assignee: Praxair Technology, Inc.Inventors: Mary Anne Knight, James Joseph Maloney
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Patent number: 5617741Abstract: Nitrogen is removed from a natural gas feed stream by a cryogenic distillation process in which said feed stream is fed to a primary column of a distillation column system having a primary column and a secondary column fed from and operating at substantially the same pressure as the primary column. At least a portion of a primary column methane-rich bottoms liquid is expanded and at least partially vaporized in heat exchange with a condensing primary column nitrogen-enriched vapor. The at least partially condensed primary column nitrogen-enriched vapor is returned to the primary column to provide higher temperature reflux to the distillation column system. A secondary column methane-rich bottoms liquid is at least partially vaporized in heat exchange with a condensing nitrogen-rich overhead vapor to produce a further methane-rich product.Type: GrantFiled: February 8, 1996Date of Patent: April 8, 1997Assignee: Air Products and Chemicals, Inc.Inventors: Brian A. McNeil, Michael H. Evans