Air Products and Chemicals, Inc.

Zbigniew Tadeusz Fidkowski

Rakesh Agrawal

Donn Michael Herron

John Frederick Cirucci

Shyam Ramchand Suchdeo

Paul Higginbotham

Steven R Auvil

Thomas Hsiao-Ling Hsiung

Jeffrey Alan Hopkins

Timothy Edward Conway

William Paul Sweeny

Lawrence Walter Pruneski

Steven Ray Auvil

A method and system for producing nitrogen and/or oxygen by air separation. The system includes at least one high pressure column, at least one low pressure column, and a reboiler-condenser. The method includes generating a high pressure nitrogen stream from the high pressure column and using energy from the high pressure nitrogen stream to provide nitrogen reflux to the high pressure column.

System and method for introducing low pressure reflux to a high pressure column without a pump

The process removes from a diluted gas one or more fluorine compounds present at a first concentration in the diluted gas and concentrates the fluorine compounds. This is done by directly contacting the diluted gas with a cryogenic liquid having a temperature less than or equal to about &minus;150&deg; F., thereby producing a vapor lean in the fluorine compounds and liquid enriched with the fluorine compounds at a second concentration. The second concentration is greater than the first concentration.

Process for concentrating fluorine compounds

The process recovers NF3 from a multicomponent fluid containing NF3, one or more components less volatile than NF3, and one or more components more volatile than NF3. The process uses a first distillation column and a second distillation column, each distillation column having a top and a bottom. The process includes the following steps: feeding the multicomponent fluid to the first distillation column at a first feed location below the top of the first distillation column; feeding a cryogenic liquid to the first or second distillation column adjacent the top of the first or second distillation column; withdrawing a mixture containing NF3 from the first distillation column; feeding the mixture to the second distillation column at a second feed location; separating NF3 from the mixture in the second distillation column; and removing a stream of NF3 from the second distillation column.

Purification of nitrogen trifluoride by continuous cryogenic distillation

Method and apparatus for recovering xenon or a mixture of xenon and krypton from air processed in a cryogenic air separation plant. An oxygen rich stream containing xenon and or krypton and xenon together with other trace impurities is subjected to a carbon dioxide and nitrous oxide removal step followed by concentration of xenon and or a mixture of krypton and xenon in a liquid fraction separated from an oxygen enriched vapor and vaporizing and recovering a xenon and or krypton and xenon mixture enriched vapor.

Method and apparatus for recovering xenon or a mixture of krypton and

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.

Distillation process to separate mixtures containing three or more

The present invention teaches an efficient and easier to operate distillation system to separate mixtures containing three or more components into streams enriched in one of the components. In this invention, a liquid stream enriched in the least volatile component is withdrawn from the bottom of one distillation column while a vapor stream enriched in the most volatile component is withdrawn from the top of another distillation column. Of these two distillation columns, the pressure of the distillation column with the bottom liquid enriched in the least volatile component is higher; and this higher pressure distillation column transfers at least two vapor streams from different locations to either one or more other distillation columns within the distillation system. For a ternary mixture, both the vapor streams are transferred to the distillation column with the top vapor enriched in the most volatile component. In the preferred mode, at least one of the vapor transfer is part of a two-way communication between the two columns, i.e., in addition to the transfer of the vapor stream, a return liquid stream is implemented between the same locations of the two columns. This invention allows the flow of all vapor streams from a higher pressure column to a lower pressure column and thereby does not suffer with the operating pressure constraints of the prior art efficient processes.

Operable and efficient distillation schemes for multicomponent

The present invention relates to an elevated pressure air separation cryogenic process wherein feed air is compressed, treated to remove water and carbon dioxide, cooled to cryogenic temperature in a main heat exchanger having a cold end and a warm end and fed to a distillation column system having at least two (2) distillation columns for separation into at least a nitrogen-enriched product, an oxygen-enriched product and a gaseous waste stream characterized in that at least a portion of said waste stream is (isentropically) expanded to produce work and work produced by the expansion is used to provide at least a portion of the work required to compress a process stream other than the gaseous waste stream at a temperature warmer than the temperature of the cold end of said main heat exchanger. The alternative process streams to be compressed can be: at least a portion of the feed air, at least a portion of the oxygen-enriched product or at least a portion of the nitrogen-enriched product.

Elevated pressure air separation process with use of waste expansion for

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. The superior performance of the invention resides in the fact that the earlier distillation column has a two-way communication from one end and a one-way communication from the other end with the subsequent distillation column.

Distillation schemes for multicomponent separations

The present invention is an improvement to a nitrogen generator enabling the process to efficiently coproduce oxygen with low recovery, typically less than 70% and preferably less than 55%, in addition to the primary product, nitrogen. In the nitrogen generator process, air is distilled in a distillation column system having a higher pressure column and a lower pressure column. The feed air is compressed, treated to remove water and carbon dioxide, cooled to near its dew point and fed to the higher pressure column of the distillation column system. The nitrogen product is produced by removing an overhead vapor stream from at least one of the columns of the distillation column system. At least one oxygen-enriched stream is removed from the lower pressure column. The improvement is characterized in that: (a) the oxygen-enriched stream is removed from the lower pressure column at a location that is at or below the feed to the lower pressure column; (b) feeding the removed oxygen-enriched stream to a supplemental distillation column for separation into an oxygen bottoms and a waste overhead; (c) providing boilup to the supplemental distillation column and (d) removing an oxygen stream (vapor or liquid) from the bottom of the supplemental distillation column as an oxygen product.

Multiple column nitrogen generators with oxygen coproduction

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.

Argon recovery from silicon crystal furnace

A process is set forth for the cryogenic distillation of an air feed to produce an oxygen product, particularly an oxygen product at moderate purity (80-99%, preferably 85-95%). The process uses an auxiliary low pressure column in addition to the conventional high pressure column and low pressure column. The auxiliary low pressure column, which is preferably operated at the same pressure as the main low pressure column and which is heat integrated with the top of the high pressure column by means of its bottom reboiler/condenser, pretreats the crude liquid oxygen from the bottom of the high pressure column. The resulting overhead vapor stream and bottom stream are subsequently fed to the main low pressure column. Preferably, the bottom stream is fed to the main low pressure column in a state which is at least partially vapor.

Process to produce moderate purity oxygen using a double column plus an

A process is set forth for the cryogenic distillation of an air feed to produce nitrogen, particularly high pressure nitrogen of various purity, varying from low purity (up to 98% nitrogen) to ultra-high purity (less than 1 part per billion of oxygen). The nitrogen may be produced at two different pressures and two different purities. The process uses an auxiliary low pressure separation zone in addition to the conventional high pressure column and low pressure column. The auxiliary low pressure separation zone, which is operated at the same pressure as the low pressure column and which is heat integrated with the top of the high pressure column by means of its bottom reboiler/condenser, pretreats the crude liquid oxygen from the bottom of the high pressure column.

Process to produce nitrogen using a double column plus an auxiliary low

A process is set forth for the cryogenic distillation of an air feed to produce high pressure nitrogen of various purity, varying from moderately high purity (99.9% nitrogen) to ultra-high purity (less than 1 part per billion of oxygen). The process is particularly suited for cases where the high pressure nitrogen is needed directly from the distillation column system to avoid contamination concerns associated with compressing nitrogen that is produced at lower pressures. The process uses a high pressure column, which operates at a pressure to directly produce the nitrogen at the desired high pressure, and one or more lower pressure columns which produces a portion of the nitrogen product at a lower pressure. At least a portion of the lower pressure nitrogen is compressed and fed to the high pressure column at a location which is below the removal location of the high pressure nitrogen.

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Macungie, PA, United States of America

Zbigniew Tadeusz Fidkowski