Adsorptive separation of nitrogen from other gases

Claim 3

The process of claim 1, wherein said type X zeolite has a silicon to aluminum ratio in the range of about 0.9 to 1.25.

Claim 4

The process of claim 2, wherein the preferential absorption of nitrogen form said gas mixture is carried out at a temperature in the range of about -190° to about 70° C. and an absolute pressure in the range of about 0.7 to 15 bar.

Claim 5

The process of claim 2, wherein said method is a cyclic adsorption process selected form pressure swing adsorption, temperature swing adsorption or a combination of these.

Claim 6

The process of claim 4, wherein said cyclic adsorption process is pressure swing adsorption and said adsorbent is regenerated at an absolute pressure in the range of about 100 to about 5000 millibar.

Claim 7

The process of claim 5, wherein the preferential adsorption of nitrogen from said gas mixture is carried out at a temperature in the range of about -20° to about 50° C. and an absolute pressure in the range of about 0.8 to 10 bar.

Claim 8

The process of claim 4, wherein said cyclic adsorption process is temperature swing adsorption and said adsorbent is regenerated at a temperature in the range of about -50° to about 300° C.

Claim 9

The process of claim 4, wherein the preferential adsorption of nitrogen from said gas mixture is carried out at a temperature in the range of about -190° to about 70° C. and an absolute pressure in the range of about 0.8 to 10 bar.

Claim 10

The method of claim 1, further comprising desorbing nitrogen from said at least one adsorption zone.

Claim 11

The method of claim 1 or claim 9, wherein said trivalent ions are selected from aluminum, cerium, lanthanum, mixtures of two or more lanthanides, and mixtures of these.

Claim 12

The method of claim 1 or claim 9, wherein said residual ions are selected from hydronium ion, calcium, strontium, magnesium, zinc, copper (II) and mixtures of these.

Claim 13

The method of claim 1, wherein said cations comprise about 70 to about 95% lithium, about 5 to about 30% of said trivalent ions and 0 to about 10% of said residual ions.

Claim 14

A cyclic adsorption process for separating nitrogen from a gas mixture comprising nitrogen and one or more of oxygen, argon, helium and hydrogen comprising the steps: (a) passing said gas mixture through at least one adsorption zone containing as adsorbent a type X zeolite whose cations comprise about 50 to about 95% lithium, about 4 to about 50% trivalent ions selected from aluminum, cerium, lanthanum, mixtures of two or more lanthanides in which the combined weight of lanthanum, cerium, praseodymium and neodymium ions present in the mixture comprises at least 50% of the total weight of the mixture, and mixtures of these, and 0 to about 10% of residual ions selected from sodium, potassium, hydronium, ammonium, calcium, strontium, magnesium, barium, zinc, copper (II) and mixtures of these, thereby preferentially adsorbing nitrogen from said gas mixture; and (b) desorbing nitrogen from said at least one adsorption zone.

Claim 15

A cyclic adsorption process for separating nitrogen from a gas mixture comprising nitrogen and one or more of oxygen, argon, helium and hydrogen comprising the steps: (a) passing said gas mixture through at least one adsorption zone containing as adsorbent a type X zeolite whose cations comprise about 50 to about 95% lithium, about 4 to about 50% trivalent ions selected from aluminum, cerium, lanthanum, mixtures of two or more lanthanides in which the combined weight of lanthanum, cerium, praseodymium and neodymium ions present in the mixture comprises at least 50% of the total weight of the mixture, and mixtures of these, and 0 to about 10% of residual ions selected from sodium, potassium, hydronium, ammonium, calcium, strontium, magnesium, barium, zinc, copper (II) and mixtures of these, thereby preferentially adsorbing nitrogen from said gas mixture; and (b) desorbing nitrogen from said at least one adsorption zone.

Claim 16

The process of claim 13, wherein said type X zeolite has a silicon to aluminum ratio in the range of about 0.9 to 1.1.

Claim 17

The process of claim 13 or claim 14, wherein said cyclic adsorption process is selected from pressure swing adsorption, temperature swing adsorption or a combination of these.

Claim 18

The process of claim 15, wherein the preferential adsorption of nitrogen from said gas mixture is carried out at a temperature in the range of about -190° to about 70° C. and an absolute pressure in the range of about 0.7 to 15 bar.

Claim 19

The process of claim 16, wherein said cyclic swing adsorption and said adsorbent is regenerated at an absolute pressure in the range of about 100 to about 5000 millibar.

Claim 20

The process of claim 17, wherein the preferential absorption of nitrogen form said gas mixture is carried out at a temperature in the range of about -20° to about 50° C. and an absolute pressure in the range of about 0.8 to 10 bar.

Claim 21

The process of claim 16, wherein said cyclic adsorption process is temperature swing adsorption and said adsorbent is regenerated at a temperature in the range of about 0° to about 300° C.

Claim 22

The process of claim 13, wherein said adsorbent is at least partly regenerated by countercurrent depressurization.

Claim 23

The process of claim 13, wherein said adsorbent is further regenerated by depressurization to subatmospheric pressure by means of vacuum.

Claim 24

The process of claim 13, wherein said adsorbent is further regenerated by purging the bed with nonadsorbed product gas from step (a).

Claim 25

Type X zeolite whose cations comprise about 50 to about 95% lithium, about 4 to about 50% trivalent ions selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these, and 0 to about 15% of residual ions selected from sodium, potassium, ammonium, hydronium, calcium, strontium, magnesium, barium, zinc, copper II and mixtures of these.

Claim 26

Type X zeolite whose cations comprise about 50 to about 95% lithium, about 4 to about 50% trivalent ions selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these, and 0 to about 15% of residual ions selected from sodium, potassium, ammonium, hydronium, calcium, strontium, magnesium, barium, zinc, copper II and mixtures of these.

Claim 27

The zeolite of claim 23, wherein said cations comprise about 70 to about 95% lithium, about 5 to about 30% of said trivalent ions and 0 to about 10% of said residual ions.

Claim 28

The zeolite of claim 23 or claim 24, wherein said trivalent ions are selected from aluminum, cerium, lanthanum, mixtures of two or more lanthanides in which the total lanthanum, cerium, praseodymium and neodymium ions present in the mixture comprises at least 50% of the total lanthanide ions, and mixtures of these.

Claim 29

The zeolite of claim 25, wherein the atomic ratio of silicon to aluminum in the zeolite lattice is between 0.9 and 1.10.

Claim 30

The zeolite of claim 23 or claim 24, wherein said residual ions are selected from hydronium ion, calcium, strontium, magnesium, zinc, copper II and mixtures of these.

Claim 31

The zeolite of claim 23, wherein the atomic ratio of silicon to aluminum in the zeolite lattice is between 0.9 and 1.25.

Claim 32

The zeolite of claim 23, wherein said cations consist substantially of lithium and said trivalent ions.

Claim 33

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising the steps: (a) contacting an aqueous solution of a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 4 to about 50 equivalent percent of the exchangeable cations are replaced with one or more of said trivalent ions; and (b) contacting an aqueous solution of a lithium salt with the trivalent ion-exchanged product of step (a), thereby producing an at least binary-exchanged type X zeolite containing about 50 to about 95 equivalent percent lithium ions and about 4 to about 50 equivalent percent trivalent ions.

Claim 34

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising the steps: (a) contacting an aqueous solution of a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 4 to about 50 equivalent percent of the exchangeable cations are replaced with one or more of said trivalent ions; and (b) contacting an aqueous solution of a lithium salt with the trivalent ion-exchanged product of step (a), thereby producing an at least binary-exchanged type X zeolite containing about 50 to about 95 equivalent percent lithium ions and about 4 to about 50 equivalent percent trivalent ions.

Claim 35

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising the steps: (a) contacting an aqueous solution of a lithium salt with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 50 to about 95 equivalent percent of the exchangeable cations are replaced with lithium ions; and (b) contacting an aqueous solution of a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with the lithium-exchanged product of step (a), thereby producing an at least binary-exchanged type X zeolite containing about 50 to about 95 equivalent percent lithium ions and about 4 to about 50 equivalent percent trivalent ions.

Claim 36

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising the steps: (a) contacting an aqueous solution of a lithium salt with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 50 to about 95 equivalent percent of the exchangeable cations are replaced with lithium ions; and (b) contacting an aqueous solution of a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with the lithium-exchanged product of step (a), thereby producing an at least binary-exchanged type X zeolite containing about 50 to about 95 equivalent percent lithium ions and about 4 to about 50 equivalent percent trivalent ions.

Claim 37

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising contacting an aqueous solution of a salt of lithium and a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 50 to about 95 equivalent percent of the exchangeable cations are replaced with lithium ions and about 4 to about 50 equivalent percent of the exchangeable cations are replaced with one or more of said trivalent ions.

Claim 38

A process for preparing a lithium- and trivalent ion-exchanged type X zeolite comprising contacting an aqueous solution of a salt of lithium and a salt of a trivalent ion selected from aluminum, scandium, gallium, iron (III), chromium (III), indium, yttrium, single lanthanides, mixtures of two or more lanthanides and mixtures of these with a type X zeolite having as exchangeable cations sodium ions, potassium ions, ammonium ions or mixtures of these until about 50 to about 95 equivalent percent of the exchangeable cations are replaced with lithium ions and about 4 to about 50 equivalent percent of the exchangeable cations are replaced with one or more of said trivalent ions.

Claim 39

The process of any one of claims 30, 31 and 32, wherein said trivalent ions are selected from aluminum, cerium, lanthanum, mixture of two or more lanthides in which the total lanthanum, cerium, praseodymium and neodymium ions present in the mixture comprises at least 50% of the total lanthanide ions, and mixture of these.

Claim 40

The process of any one of claims 30, 31 and 32, wherein said type X zeolite is low silicon X zeolite.