Electrolytic oxygen purification

Abstract

The present invention relates to a method for purifying an oxygen stream contaminated with water, hydrogen, and optionally nitrogen, the method comprising contacting the oxygen stream to be purified with a zeolitic adsorbent material comprising at least one metal in zero-valent metallic form or in an oxidized or reduced form, and recovering the purified oxygen stream. The invention also relates to the use of a zeolitic adsorbent material containing at least one transition metal for the purification of oxygen, and to the use of the oxygen thus purified in an industrial process.

Description

[Technical Field]

[0001] The present invention relates to a method for purifying oxygen from an electrolytic cell, and more particularly to a method for purifying oxygen containing water and hydrogen, and optionally trace amounts of nitrogen and / or trace amounts of residual electrolyte, such as potassium hydroxide. [Background technology]

[0002] Currently, oxygen purification is a major problem: hydrogen has been obtained in large quantities by steam reforming, but current ecological constraints related to global warming have prompted scientists to reconsider the electrolysis of water to produce hydrogen.

[0003] In this electrolysis process, water molecules are split to yield one mole of hydrogen and one-half mole of oxygen according to the chemical equation HO → H + 1 / 2O. Consequently, water electrolysis produces significant amounts of oxygen, which must be purified for effective use. Specifically, oxygen produced by water electrolysis is frequently contaminated with co-produced hydrogen, particularly due to excessive hydrogen permeation through the separation membrane or dissolution of hydrogen in the electrolyte. The water present in the oxygen stream generally originates from gas entrainment, while nitrogen originates, for example, from the inert phase during start-up of the electrolytic cell and from dissolution in cold water introduced into the electrolytic cell, often under pressure. As a result, the contaminants removed from the oxygen stream are hydrogen, nitrogen, water, and possibly trace amounts of electrolyte, such as KOH.

[0004] In particular, certain industrial applications and processes require oxygen that is as pure as possible and has as high a purity as possible, for example greater than 99%, in order to optimize the effectiveness of the oxygen in those processes or applications.

[0005] The prior art already provides numerous solutions specifically for removing hydrogen contained in gases. For example, EP 0 089 183 describes a method for removing hydrogen from gases that may also contain oxygen. The method involves contacting the gas at room temperature with a catalyst comprising an alumina-tin oxide support impregnated with 0.25% to 2.5% by weight of platinum and 0.25% to 2.5% by weight of palladium. The operation is carried out at room temperature. Hydrogen is oxidized to water, but water is not removed. The input hydrogen content is in the range of 0.2% to 2%, and the output hydrogen content is in the range of 0.04% to 0.09%.

[0006] Y. Jang et al. ("Effect of a modified 13X zeolite support in Pd-based catalysts for hydrogen oxidation at room temperature", RSC Adv, 11 (2021), 38047-38053) studied the effectiveness of modified 13X zeolite doped with palladium for the oxidation of hydrogen to water. More specifically, the authors demonstrated that the activity of the catalyst was significantly enhanced when 13X zeolite was treated with acid followed by specific calcination. In this paper, the zeolite was treated with acid, which resulted in the deterioration of its crystalline structure. Therefore, it is not the zeolite that is involved in the oxidation of hydrogen to water.

[0007] The work of O. Yu. Golubeva et al. ("Catalytic hydrogen oxidation using zeolite RHO modified by silver nanoparticles", Glass Physics and Chemistry, 38(5), (2012), 455-459) describes the catalytic activity of RHO zeolite modified with silver ions. It has been shown that the incorporation of a large amount of silver (more than 17%, expressed as AgO) into the RHO structure allows the oxidation of hydrogen in air (mostly nitrogen). The reaction is carried out at high temperatures (about 200 °C). However, no indication of the presence or removal of water is given.

[0008] The prior art does not currently provide an acceptable solution. However, while it may be considered that nitrogen and water could be easily removed by passing them over CaX and 4A type sieves, respectively, separation of hydrogen would be more difficult in this case, since this gas would not be adsorbed onto the sieve. Thus, there is currently no acceptable industrial solution for purifying gas streams containing hydrogen, water, nitrogen, and possibly oxygen contaminated with traces of residual electrolyte. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent No. 0089183 [Non-patent literature]

[0010] [Non-Patent Document 1] Y.Jang et al.(“Effect of a modified 13X zeolite support in Pd-Based catalysts for hydrogen oxidation at room temperature”, RSC Adv, 11 (2021), 38047-38053) [Non-patent document 2] O.Yu.Golubeva et al.(“Catalytic hydrogen oxidation using zeolite RHO modified by silver nanoparticles”, Glass Physics and Chemistry, 38(5), (2012), 455-459) Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, there remains a need for an oxygen purification method that is readily industrializable, inexpensive, and easy to implement, and in particular an oxygen purification method that is cheaper and easier to implement than the techniques known today.It is therefore an object of the present invention to provide an oxygen purification method that overcomes the drawbacks encountered in the prior art, in particular to purify oxygen in a simpler manner, and in particular to remove both hydrogen and water that are present as impurities in the oxygen stream.

[0012] Another object of the present invention is to provide an oxygen purification process which allows for the simultaneous removal of not only hydrogen and water present as impurities in the oxygen stream, but also other impurities such as nitrogen and traces of residual electrolyte, e.g., potassium hydroxide, and in particular the hydrogen stream from the electrolytic cell, also referred to as electrolytic oxygen. Other objects will become apparent in light of the following description of the invention.

[0013] The applicant has now found that it is possible to purify oxygen streams, in particular electrolytic oxygen streams, by meeting all or at least some of the objectives disclosed above, in particular by removing or at least significantly reducing the content of hydrogen and water, and where appropriate the content of nitrogen and other traces of residual electrolytes, in a simple, effective and relatively inexpensive manner, and most particularly by overcoming all or some of the problems encountered in the prior art.

[0014] Unless otherwise indicated in the following disclosure of the present invention, all ranges of values, particularly those identified by "between" or "to," are understood to be inclusive. Unless otherwise specified, all percentages are percentages by weight.

[0015] The present invention therefore proposes an "all-in-one" method for purifying and drying oxygen by removing both hydrogen and water using a single zeolitic adsorbent material, in which the zeolite has undergone at least partial cation exchange and / or impregnation with at least one transition metal. [Means for solving the problem]

[0016] The subject of the present invention is more particularly a method for purifying an oxygen stream containing water, hydrogen and optionally nitrogen, comprising: - at least one step of contacting the oxygen stream to be purified with a zeolitic adsorbent material containing at least one metal in zero-valent metallic form or in oxidized or reduced form, and - recovering at least one purified oxygen stream. DETAILED DESCRIPTION OF THE INVENTION

[0017] In one embodiment of the present invention, the purified oxygen comprises electrolytic oxygen, i.e., oxygen obtained by electrolysis of water. In a preferred embodiment, the purified oxygen comprises primarily oxygen, i.e., 60 mol% to 99.99 mol% pure oxygen, preferably 80 mol% to 99.99 mol% pure oxygen, more preferably 90 mol% to 99.99 mol% pure oxygen, even more preferentially 95 mol% to 99.99 mol% pure oxygen, and typically 96.50 mol% to 99.99 mol% pure oxygen. As mentioned above, the purified oxygen contains at least water and hydrogen as impurities, and in some cases also nitrogen.

[0018] The zeolitic adsorbent material used in the present invention is a particulate material comprising at least one zeolite exchanged and / or impregnated with one or more metals in their zero-valent metal form or in their oxidized or reduced form.

[0019] The term "metal" refers to metals of the periodic table of the elements, excluding metalloids and non-metals, in particular metals of columns 3 to 15 of the periodic table of the elements. Preferably, the term "metal" refers to metals of columns 3 to 14 of the periodic table of the elements, excluding metalloids and non-metals, more preferably the term "metal" refers to metals selected from palladium, platinum, silver, titanium, tin, zinc, nickel, cobalt, iron and copper, and the lanthanides and actinides, either alone or as a mixture of two or more.

[0020] More preferably, the metal is selected from palladium (Pd), platinum (Pt), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn), tin (Sn), cobalt (Co), and mixtures of two or more thereof, in any proportion, with palladium (Pd), platinum (Pt), copper (Cu), nickel (Ni), tin (Sn), iron (Fe), and mixtures of two or more thereof, in any proportion, being entirely preferred. Examples of metal mixtures that may be mentioned include, but are not limited to, Pd / Ni, Pt / Ni, Pd / Pt / Ni, Sn / Pd, Sn / Pt, Sn / Pd / Pt, and Cu / Ag.

[0021] Of course, other metals may be used, but the preferred metals and metal mixtures listed above have been found to be the most particularly effective and advantageous in terms of their effectiveness / supply cost ratio.

[0022] The zeolitic adsorbent material that can be used in the method of the present invention consequently comprises at least one zeolitic adsorbent material and at least one metal, as disclosed above. The at least one metal may be present in the zeolitic adsorbent material in its native form (or metallic form, i.e., zero valence, equal to 0) or oxidized form, fully or at least partially adsorbed on the at least one zeolite, or may be present in its reduced form. The metal may also be present in the zeolitic adsorbent material in ionic form, in which case the metal contributes in whole or at least in part to the electronic neutrality of the zeolitic adsorbent material.

[0023] Thus, the zeolitic adsorbent material that can be used in the process of the present invention comprises at least one metal as just defined, which can be provided in the zeolite structure, i.e., deposited and / or impregnated and / or included by ion exchange, as described below.

[0024] This provision is achieved according to conventional methods well known to those skilled in the art, and is generally and advantageously achieved by means of one or more aqueous, organic or aqueous-organic salt solutions, at least one of which contains one or more metal salts, preferably selected from nitrates, acetates, sulfates, etc. of said metals.

[0025] The total mass of metals provided in the zeolite structure is typically between 0.1% and 9% by mass, inclusive, more typically between 0.1% and 7% by mass, preferably between 0.5% and 6% by mass, and more preferably between 1% and 5% by mass, based on the total weight of the zeolitic adsorbent material used in the process of the present invention. This mass content is measured by X-ray fluorescence (FluoX) analysis, as described later in this specification.

[0026] According to a preferred embodiment, when the metal is at least partially or completely deposited or impregnated in the zeolite crystals, the particle size of the metal particles is between 1 nm and 250 nm, preferably between 5 nm and 250 nm, more preferably between 5 nm and 100 nm, even better between 5 nm and 50 nm, for example about 15 nm to 20 nm, as determined by observation with a scanning electron microscope (SEM) equipped with a STEM ("scanning transmission electron microscope") detector.

[0027] As mentioned above, among the preferred metals, copper is preferably used, in which case the copper content in the zeolitic adsorbent material used in the process of the present invention is preferably, usually inclusively, 0.1% to 9% by mass, preferably 0.1% to 7% by mass, preferably 0.5% to 6% by mass, more preferably 1% to 5% by mass, based on the total weight of the zeolitic adsorbent material, which is particularly significantly lower than that encountered in copper-containing zeolitic adsorbent materials known from the prior art, also known as copper-doped zeolitic adsorbents.

[0028] According to a preferred embodiment, the method of the present invention is carried out using a zeolitic adsorbent material containing copper and at least one other metal, preferably selected from zinc (Zn) and silver (Ag), but also from palladium (Pd), platinum (Pt), iron (Fe), tin (Sn), and cerium (Ce), in any proportion, and mixtures thereof, limited to the most common mixtures. The content of the at least one other metal is generally lower than the copper content, e.g., about 20% by mass relative to the copper content, preferably about 10% by mass relative to the copper content, more commonly 0.1% to 20% by mass relative to the copper content, and usually 0.1% to 10% by mass. However, the content of the at least one other metal may, in some cases, if desired, be equal to or greater than the copper content, particularly 1% to 100% by mass relative to the copper content, advantageously 5% to 70% by mass or more, and even better 10% to 70% by mass or more.

[0029] According to another preferred embodiment, the method of the present invention is carried out using a zeolitic adsorbent material containing palladium (Pd) and optionally at least one other metal selected from zinc (Zn), silver (Ag) and tin (Sn), limited to the most common mixtures, but also platinum (Pt), iron (Fe), and cerium (Ce), in all proportions, and mixtures thereof.

[0030] According to another preferred embodiment, the method of the present invention is carried out using a zeolitic adsorbent material containing platinum (Pt) and optionally at least one other metal selected from platinum (Zn), silver (Ag) and tin (Sn), limited to the most common mixtures, but also palladium (Pd), iron (Fe), and cerium (Ce), in all proportions, and mixtures thereof.

[0031] The at least one zeolite present in the zeolitic adsorbent material that can be used in the process of the present invention may be of any type known to those skilled in the art, and may be natural, artificial (modified natural zeolite), or synthetic (synthetically obtained). Preferably, the at least one zeolite is selected from LTA, FAU, RHO, MFI zeolites, and mixtures of two or more thereof. Most particularly preferred are zeolites selected from FAU-type zeolites, MFI-type zeolites, and mixtures thereof, in all proportions and with all Si / Al ratios. Advantageously, for information on the various zeolite types listed above, reference may be made to the book "Atlas of Zeolite Framework Types", Elsevier, 5th edition (2001).

[0032] It will be understood that the zeolitic adsorbent material that may be used in the process of the present invention may comprise, to name a few illustrative examples, one or more zeolites of the same or different type, for example, a zeolite selected from X-type, Y-type, or MFI-type zeolites, alone or in mixtures, for example, X zeolite alone or together with MFI-type zeolite, or Y zeolite, for example, alone or together with MFI-type zeolite, or MFI-type zeolite alone, or X zeolite mixed with Y zeolite, or mixtures of MFI-type zeolite with zeolite X and zeolite Y, and that no limitation of the scope of the present invention is intended. Consequently, it would not depart from the context of the present invention if the zeolitic adsorbent material were formed from a mixture of structures having different Si / Al molar ratios.

[0033] According to one embodiment of the present invention, the Si / Al ratio of the zeolite, or the apparent overall ratio of the zeolite mixture if several are present in the zeolitic aggregate material, may have any value between 1 and 100. According to a preferred embodiment, this Si / Al ratio is between 1 and 80, more preferably between 1 and 50, advantageously between 1 and 20. Most preferably, this Si / Al ratio is between 2 and 100, even more preferably between 2 and 80, more preferably between 2 and 50, and very advantageously between 2 and 20.

[0034] Zeolitic adsorbent materials that can be used in the process of the present invention can also include hierarchically porous homologues of the above-listed zeolites. Hierarchically porous zeolites are well known to those skilled in the art and can be prepared, for example, according to the procedures described in patent applications WO 2015 / 019013 and WO 2015 / 028740, or can be prepared by chemical, physical, or physicochemical post-treatment of conventional zeolites that are not hierarchically porous, also known as non-mesoporous zeolites.

[0035] The term "zeolitic adsorbent material" means zeolite crystals or a mixture of crystals of different zeolites, optionally agglomerated with one or more agglomerating binders well known to those skilled in the art, for example selected from alumina, silica, and clay. Agglomeration may be carried out before or after the operation to deliver the metals.

[0036] According to a preferred embodiment, the zeolitic adsorbent material of the present invention is in the form of an aggregate, i.e., a material in which zeolite crystals have been aggregated with the aid of an aggregate binder, as is fully known to those skilled in the art. The aggregate binder may be of any type, but for the purposes of the present invention, aggregate binders selected from clays, aluminas, silicates, and mixtures of two or more thereof in any proportion are preferred, preferably the aggregate binder is selected from clays, more preferably from kaolin clays such as kaolin, dickite, halloysite, kaolinite, nacrite, etc.

[0037] The binder ratio, i.e. the mass of the agglomerate binder relative to the total weight of the zeolitic adsorbent material, is within the range known to those skilled in the art and is generally between 0.1% and 30% by weight, preferably between 1% and 30%, more preferably between 5% and 30%, advantageously between 10% and 30%.

[0038] When the zeolite crystals are agglomerated with at least one agglomerating binder, it may also be advantageous or even desirable to add one or more additives or fillers well known to those skilled in the art, including, by way of illustrative and non-limiting examples only, the main additives commonly used when agglomerating zeolite crystals with agglomerating binders, in particular additives selected in any proportion from molding aids, pore formers, silica, carboxymethylcellulose, and the like, and mixtures of two or more thereof.

[0039] If the binder is a zeolitizable binder, such as kaolin, kaolinite, etc., it can be totally or partially zeolitized, i.e. converted into zeolite, as is well known to those skilled in the art, generally and usually under the action of a base, for example sodium hydroxide solution.

[0040] Zeolitic adsorbent materials suitable for use in the process of the present invention are generally usually in the form of beads, but can take any other shape, such as needles, cylinders, hollow cylinders, discs, trilobes, tetralobes, extrudates, crushed forms, and other forms.

[0041] The zeolitic adsorbent material can have any size and dimension, but zeolitic adsorbent materials having a volume average diameter of 0.1 mm to 10 mm, preferably 0.1 mm to 5 mm, more preferably 0.5 mm to 5 mm, advantageously 1 mm to 5 mm are preferred and commonly used.

[0042] Zeolitic adsorbent materials suitable for use in the process of the present invention are either commercially available or can be obtained using conventional techniques well known to those skilled in the art, or techniques that can be easily adapted from known operating procedures obtained from the literature or the internet.

[0043] In one embodiment, the zeolitic adsorbent material can be readily prepared from a zeolitic adsorbent, based on conventional zeolites and / or based on hierarchically porous zeolites, comprising one or more alkali metal and / or alkaline earth metal cations, in particular lithium, sodium, potassium, calcium, strontium or barium, and optionally a fully or at least partially zeolitic aggregate binder, which zeolitic adsorbent is subjected to an impregnation and / or ion exchange treatment with at least one metal as defined above, generally in salt form, according to conventional techniques well known to those skilled in the art.

[0044] Alternatively, a step of impregnation and / or ion exchange with at least one metal as defined above may be carried out directly on the zeolite crystals before agglomeration and shaping with the binder.

[0045] According to a preferred embodiment, the method for preparing a zeolitic adsorbent material that can be used in the context of the present invention comprises at least the following steps: a) one or more cation exchanges and / or impregnations of zeolite crystals with one or more salt solutions of at least one metal selected from the metals of columns 8 to 15 of the periodic table of the elements, excluding non-metals and metalloids, as defined above; b) flocculation with at least one flocculating binder; c) heat treatment (baking) to harden the cohesive binder; d) optionally at least partially zeolitizing the aggregate binder; and e) Recovery and optional activation of the zeolitic adsorbent material that may be used in the context of the present invention, generally activation between 100°C and 550°C.

[0046] In the above method, step a) may be carried out one or more times before step b) and / or after steps c) and / or d).

[0047] A baking step is generally carried out preferably between steps b) and d), generally at a temperature of between 400° C. and 600° C., although this is by no means essential. Alternatively, if a baking step is carried out, it may be possible to carry out step a) after this baking step and before step d), regardless of whether step a) has already been carried out before step b).

[0048] According to a preferred embodiment of the method for preparing a zeolitic adsorbent material that can be used in the method of the present invention, the step of forming the aggregate material into a shape is carried out according to any method known to those skilled in the art. This step of forming into a shape may be carried out during or after the aggregation step b) and may be followed by one or more cation exchange and / or impregnation steps a).

[0049] The heat treatment step described in the above method must not result in significant sintering of the metal atoms, which must remain as dispersed as possible in the zeolite. This can be easily observed by scanning electron microscopy (SEM) or transmission electron microscopy (TEM). Sintering of the metal atoms is easily avoided, in particular, by careful and strict control of the heat treatment temperature and time, as is well known.

[0050] Such methods for preparing zeolitic adsorbent materials exchanged and / or impregnated with one or more transition metals are well known to those skilled in the art, and reference may be made, for example, in a non-limiting manner, to EP 1 125 635 or to the document "Metal Sites in Zeolites: Synthesis, Characterization and Catalysis", Q. Zhang et al., Chem. Rev. (2023), 123(9), 6039-6106, for a precise description of how zeolitic adsorbent materials that can be used in the context of the method of the present invention are prepared.

[0051] More particularly, cation exchange can be carried out according to any method known to those skilled in the art, for example, by contacting the zeolitic adsorbent material with one or more, preferably aqueous, salt solutions, at least one of which contains one or more metal salts. The cation exchanges can be single or multiple, and if multiple, successive exchanges can be with the same or different salt solutions, each exchange step being preceded and / or followed by at least one washing and / or heat treatment step, the heat treatment being optionally an oxidizing or reducing treatment.

[0052] The impregnation operation, whether wet or dry impregnation, can also be easily carried out according to any method known to those skilled in the art. The term "wet impregnation" refers to placing the zeolitic adsorbent material in aqueous and / or organic suspension in contact with one or more, preferably aqueous, salt solutions, at least one of which contains one or more metal salts, the wet impregnation operation optionally preceded and / or followed by at least one heat treatment step, which is optionally an oxidation or reduction treatment. The term "dry impregnation" refers to contacting the zeolitic adsorbent material with a precise volume of one or more, preferably aqueous, salt solutions, at least one of which contains one or more metal salts, the dry impregnation operation optionally preceded and / or followed by at least one heat treatment step, which is optionally an oxidation or reduction treatment.

[0053] The various steps listed above, cation exchange and / or impregnation, may be carried out one or more times or may be combined, for example a cation exchange operation followed by a wet or dry impregnation operation, a washing step after the cation exchange, and optionally a heat treatment before the impregnation operation.

[0054] These different cation exchange and impregnation operations result in the presence of at least one metal in the form of a cation in the zeolitic adsorbent material. Prior to use in the process of the invention, and if necessary or desirable, treatment with a reducing element, for example advantageously under a stream of hydrogen gas, makes it possible to reduce the valence of the metal, possibly down to a valence of zero.

[0055] Non-limiting examples of zeolite-based adsorbent materials that can be used in the process of the present invention are as follows:

[0056] Sodium MFI (MFI-Na) zeolite or protonated MFI (MFI-H) zeolite with a Si / Al molar ratio of 10 to 20 and a content of 0.1% to 7% of at least one metal selected from Pd, Pt, Ni, Ti, Co, Zn, Ce, Fe, Cu, Sn and Ag, either alone or as a mixture of two or more thereof.

[0057] FAU sodium (FAU-Na) zeolite or protonated FAU (FAU-H) zeolite with a Si / Al molar ratio of 1.25 to 20 and a content of 0.1% to 7% of at least one metal selected from Pd, Pt, Ni, Ti, Co, Zn, Ce, Fe, Cu, Zn, Sn and Ag, either alone or as a mixture of two or more thereof.

[0058] Sodium LTA (LTA-Na) zeolite or protonated LTA (LTA-H) zeolite with a Si / Al molar ratio equal to 1 and a content of 0.1% to 7% of at least one metal selected from Pd, Pt, Ni, Ti, Co, Zn, Ce, Fe, Cu, Zn, Sn and Ag, either alone or as a mixture of two or more thereof.

[0059] Sodium RHO (RHO-Na) zeolite or protonated RHO (RHO-H) zeolite with a Si / Al molar ratio of 1 to 20 and a content of 0.1% to 7% of at least one metal selected from Pd, Pt, Ni, Ti, Co, Zn, Ce, Fe, Cu, Zn, Sn and Ag, either alone or as a mixture of two or more thereof.

[0060] According to a preferred embodiment, the zeolitic adsorbent material used in the present invention is a particulate material comprising at least one zeolite exchanged or impregnated with one or more metals selected from palladium, platinum, silver, titanium, tin, zinc, nickel, cobalt, iron and copper, in zero-valent metal form or in oxidized or reduced form.

[0061] A most particularly preferred embodiment of the process of the present invention uses a zeolitic adsorbent material which is a particulate material comprising at least one zeolite exchanged or impregnated with a metal selected from copper, palladium, platinum, iron and zinc, in any proportion, either alone or as a mixture of two or more thereof.

[0062] According to yet another preferred embodiment, the process of the present invention uses a zeolitic adsorbent material which is a particulate material comprising at least one faujasite (FAU) type zeolite, preferably an FAU type zeolite having a Si / Al ratio of 1 to 100, for example an FAU-X type zeolite or an FAU-Y type zeolite, preferably an FAU-Y type zeolite, further comprising sodium and copper, or copper mixed or alloyed with one or more metals selected from palladium, platinum, tin, iron, and zinc, and a transition metal is optionally exchanged or impregnated with the zeolitic adsorbent material.

[0063] According to another preferred embodiment, the process of the present invention uses a zeolitic adsorbent material which is a particulate material comprising at least one faujasite (FAU) type zeolite, preferably an FAU type zeolite having a Si / Al ratio of 2 to 100, such as an FAU-Y type zeolite further comprising sodium and copper, or copper mixed or alloyed with one or more metals selected from palladium, platinum, iron, tin, and zinc, the metals optionally being exchanged and / or impregnated with the zeolitic adsorbent material.

[0064] According to yet another preferred embodiment, the process of the present invention uses a zeolitic adsorbent material which is a particulate material comprising at least one MEI type zeolite, preferably an MFI type zeolite having a Si / Al ratio of 10 to 100, sodium, and further comprising copper or copper mixed or alloyed with one or more metals selected from palladium, platinum, iron, and zinc, the metals optionally being exchanged or impregnated with the zeolitic adsorbent material.

[0065] In preferred embodiments, examples of zeolite-based adsorbent materials that can be used in the process of the present invention are as follows:

[0066] Protonated FAU Protonated FAU zeolite with a Si / Al ratio between 2 and 10 and a Pd content between 0.1% and 1% by weight, Protonated FAU zeolite with a Si / Al ratio between 2 and 10 and a Pt content between 0.1% and 1% by weight, Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Ni content of 1% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Ti content of 4% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2-10 and a Co content of 4%-7% by weight, Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Zn content of 4% to 7% by weight, Protonated FAU zeolite with a Si / Al ratio of 2-10 and a Ce content of 4%-7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2-10 and an Fe content of 4%-7% by weight, Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Cu content of 4% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Zn content of 4% to 7% by weight, Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and an Sn content of 4% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and an Ag content of 4% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio of 2 to 10 and a Ti content of 4% to 7% by weight; Protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 2% and 4% by weight, and a palladium content between 0.1% and 1% by weight; protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a palladium content between 0.1% and 1% by weight; protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a platinum content between 0.1% and 1% by weight; Protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a nickel content between 0.1% and 5% by weight; Protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and an iron content between 0.1% and 5% by weight; Protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a cobalt content between 0.1% and 1% by weight; protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a zinc content between 0.1% and 5% by weight; protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a titanium content between 0.1% and 5% by weight; Protonated FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a tin content between 0.1% and 5% by weight; Sodium FAU Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Pd content of 0.1% to 1% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Pt content of 0.1% to 1% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Ni content of 1% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Ti content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Co content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10 and a Zn content between 4% and 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Ce content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10 and an Fe content between 4% and 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Cu content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10 and a Zn content between 4% and 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and an Sn content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and an Ag content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio of 2 to 10 and a Ti content of 4% to 7% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 2% and 4% by weight, and a palladium content between 0.1% and 1% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a palladium content between 0.1% and 1% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a platinum content between 0.1% and 1% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a nickel content between 0.1% and 5% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and an iron content between 0.1% and 5% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a cobalt content between 0.1% and 1% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a zinc content between 0.1% and 5% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a titanium content between 0.1% and 5% by weight; Sodium FAU zeolite with a Si / Al ratio between 2 and 10, a copper content between 0.5% and 2% by weight, and a tin content between 0.1% and 5% by weight; Protonated MFI Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Pd content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Pt content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Ni content of 1%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Ti content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Co content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Zn content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Ce content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and an Fe content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Cu content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Zn content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and an Sn content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and an Ag content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20 and a Ti content of 4%-7% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 2%-4% by weight, and a palladium content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a palladium content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a platinum content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a nickel content of 0.1%-5% by weight; Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and an iron content of 0.1%-5% by weight; Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a cobalt content of 0.1%-1% by weight, Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a zinc content of 0.1%-5% by weight; Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a titanium content of 0.1%-5% by weight; Protonated MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a tin content of 0.1%-5% by weight, Sodium MFI Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Pd content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Pt content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Ni content of 1%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Ti content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Co content of 4%-7% by weight, Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Zn content of 4%-7% by weight, Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Ce content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and an Fe content of 4%-7% by weight, Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Cu content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Zn content of 4%-7% by weight, Sodium MFI zeolite with a Si / Al ratio of 10-20 and an Sn content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and an Ag content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20 and a Ti content of 4%-7% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 2%-4% by weight, and a palladium content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a palladium content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a platinum content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a nickel content of 0.1%-5% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and an iron content of 0.1%-5% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a cobalt content of 0.1%-1% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a zinc content of 0.1%-5% by weight; Sodium MFI zeolite with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a titanium content of 0.1%-5% by weight; · Sodium MFI zeolites with a Si / Al ratio of 10-20, a copper content of 0.5%-2% by weight, and a tin content of 0.1%-5% by weight.

[0067] As previously mentioned, the method of the present invention is an "all-in-one" oxygen purification method by removing both hydrogen and water present as impurities in an oxygen stream, more particularly an oxygen stream that includes or consists of electrolytic oxygen.

[0068] The term "all-in-one" method means that passage over a zeolite adsorbent material allows for the simultaneous (i.e., concomitant) at least partial or even total removal (content below the detection threshold) of hydrogen and water present in the oxygen stream within the same temperature range. It is well known to those skilled in the art that zeolites must operate at high temperatures to remove hydrogen, and that at high temperatures zeolites adsorb little or no water and tend to desorb it. Therefore, the "all-in-one" method of the present invention has the great advantage of removing both hydrogen and water, and possibly other impurities, from the oxygen stream while eliminating the step of changing the temperature range, thus facilitating an industrial process in terms of time, energy consumption, and productivity. The method of the present invention can therefore be considered to allow the purification of an oxygen stream without the supply of external energy, for example, without the supply of external heat.

[0069] As previously mentioned, the present invention relates to a method for purifying an oxygen stream, in particular an electrolytic oxygen stream, containing hydrogen and water as impurities to be removed, and optionally nitrogen, and optionally other impurities inherent in oxygen synthesis processes, in particular electrolytic oxygen synthesis processes.

[0070] The purification process of the present invention can therefore be carried out according to any method known to those skilled in the art of gas purification, more particularly by adsorption of impurities onto a zeolitic adsorbent material as defined above. For example, the adsorption process according to the present invention can be selected from pressure and / or temperature swing processes, typically PSA ("Pressure Swing Adsorption"), PVSA ("Pressure Vacuum Swing Adsorption", which relies on desorption at subatmospheric pressure), TSA ("Temperature Swing Adsorption"), PTSA ("Pressure Temperature Swing Adsorption"), PVTSA ("Pressure Vacuum Temperature Swing Adsorption", which relies on desorption at subatmospheric pressure).

[0071] The fluid to be purified contains, as indicated above, mainly oxygen, but also water, hydrogen, and possibly nitrogen. The water content is generally between 20 ppmv and 1.5 mol%, preferably between 50 ppmv and 1.5 mol%, more preferably between 100 ppmv and 1.5 mol%, advantageously between 200 ppmv and 1.5 mol%. The hydrogen content of the stream is generally between 5 ppmv and 1 mol%, preferably between 5 ppmv and 5000 ppmv, more preferably between 5 ppmv and 3000 ppmv, even more preferably between 5 ppmv and 1000 ppmv. The nitrogen content is between 0 and 1 mol%, generally between 10 ppmv and 1 mol%.

[0072] The process according to the invention can be carried out according to any conventional gas separation method, for example by passing the gas through one or more columns (also called "adsorbers" or more simply "reactors") containing at least one bed of a zeolitic adsorbent material as just defined. According to one embodiment, the process of the invention is carried out using at least two adsorbers, via techniques well known to those skilled in the art, especially when working with continuous flow.

[0073] Thus, the fluid to be purified is generally contacted with the zeolitic adsorbent material at a pressure of from 0.5 MPa to 5 MPa, preferably from 0.9 MPa to 5 MPa, more preferably from 1.5 MPa to 5 MPa, and at a temperature of from 10°C to 100°C, preferably from 15°C to 90°C, advantageously from 20°C to 60°C, typically from 25°C to 55°C.

[0074] In a preferred embodiment, after the adsorption step, the bed of zeolitic adsorbent material is regenerated, i.e., desorbed either by reduced pressure and countercurrent discharge (PSA and VPSA processes) or by temperature reduction (TSA processes), optionally in combination with reduced pressure and countercurrent discharge (PVTSA processes).

[0075] For PSA and VPSA processes, the desorption pressure is generally between 0.1 MPa and 1 MPa on the one hand and between 500 Pa and 95 kPa on the other hand. As a general rule, for obvious reasons of ease of process implementation and energy savings, the desorption temperature is close to the adsorption temperature; in other words, deliberate temperature changes are generally not made.

[0076] According to yet another preferred embodiment of the invention, a purge step may be carried out at the end of the desorption step by countercurrent reintroduction of a portion of the purified gas, typically less than 20% of the stream produced by the adsorber.

[0077] It should be understood that the process of the present invention may also include one or more pressure equalization steps between any of the different adsorbers. Pressure equalization steps can be advantageously carried out between the adsorption and desorption steps according to techniques well known to those skilled in the art. The advantage of providing one or more pressure equalization steps is, in particular, to minimize oxygen and hydrogen losses throughout the process. Similarly, it may be envisaged to recycle the gas collected during desorption, as is customary in hydrogen PSA processes.

[0078] For TSA and PVTSA processes, a portion of the purified gas (typically less than 20% of the stream produced by the adsorber) is heated to a temperature between 40°C and 250°C and then injected countercurrently into the adsorber, possibly at reduced pressure relative to the adsorbed phase (PVTSA), i.e., 1 kPa to 3 MPa. As with PSA and VPSA, different pressure equalization and purge configurations can be envisaged.

[0079] In the method of the present invention, the adsorption and desorption phases cyclically follow each other. The method may optionally include a cooling system integrated into the adsorber to avoid or at least minimize excessive heating of the adsorbent bed, which, as indicated above, inhibits water adsorption by the particulate zeolitic adsorbent material. The method may also include the step of drying the gas stream before and / or after passing it over the zeolitic adsorbent material containing at least one metal according to the present invention.

[0080] The fact that it can be dried, i.e. that the water present or formed can be adsorbed in the same material, allows for the simplification of the processes downstream of the electrolytic cell, while at the same time producing a high purity oxygen stream of the quality required in particular for many fields of application.

[0081] The method of the present invention therefore has many advantages, most particularly that it is capable of both reducing the dissolved hydrogen in an oxygen stream and adsorbing any water already present in the oxygen stream as well as water formed by the reduction of dissolved oxygen. The method of the present invention therefore makes it possible to easily and industrially obtain high purity oxygen streams, particularly oxygen streams having a purity of more than 99%, more particularly electrolytic oxygen streams having a purity of more than 99% and containing less than 5 ppmv of hydrogen and less than 1 ppmv of water, the amounts of these impurities being determined according to conventional techniques well known to those skilled in the art, for example using an ionization mass spectrometer.

[0082] According to another aspect, the invention relates to the purified oxygen stream obtained according to the method described above and its use as an industrial product or reagent in various fields, such as the metallurgical or medical fields, to name just a few known applications. It should be noted that one of the main advantages is the possibility to provide oxygen that is free or substantially free of hydrogen, for obvious safety reasons.

[0083] According to another aspect, the present invention relates to the use of a zeolitic adsorbent material as defined above for the purification of oxygen streams, in particular for the purification of electrolytic oxygen.

[0084] According to yet another aspect, the present invention relates to a method for preparing high purity oxygen, comprising at least the following steps:

[0085] 1) electrolysis of an aqueous solution containing primarily hydrogen oxide to produce a hydrogen stream and an oxygen stream; 2) Recovery of the oxygen stream from the electrolysis step 1); 3) Purifying the oxygen stream recovered in step 2) by passing it over a zeolitic adsorbent material, as defined above; and 4) Recovery of high purity oxygen.

[0086] It will be appreciated that the method for preparing high purity oxygen according to the present invention comprises an electrolysis step 1) which can be carried out in a conventional manner well known to those skilled in the art.

[0087] This method therefore allows the production of very high purity oxygen in an efficient and economical manner, in particular more economically than the currently known synthetic methods for preparing oxygen by electrolysis of water.

[0088] analysis technology Si / Al molar ratio and degree of exchange The determination of the Si / Al molar ratio and the degree of exchange is carried out by any chemical analysis technique known to those skilled in the art, among which mention may be made of the technique of chemical analysis by X-ray fluorescence as described in standard NF EN ISO 12677:2011 on a wavelength dispersive spectrometer (WDXRF), for example a Bruker Tiger S8 machine.

[0089] X-ray fluorescence is a spectral technique that utilizes the photoluminescence of atoms in the X-ray range to establish the elemental composition of a sample. Excitation of atoms, typically by an X-ray beam or electron bombardment, produces specific radiation after the atoms return to their ground state. X-ray fluorescence spectroscopy has the advantage of being largely independent of the chemical elemental combination, resulting in accurate determinations, both quantitatively and qualitatively. After calibration for each oxide, measurement uncertainties of less than 0.4% by weight are typically obtained.

[0090] These elemental chemical analyses make it possible to ascertain the Si / Al molar ratio of the starting zeolite, the content of deposited metals, and the quality of the ion exchange. In the present description, the uncertainty in the measurement of the Si / Al molar ratio is ±5%. The quality of the ion exchange is related to the number of moles of sodium oxide NaO remaining in the agglomerated zeolitic adsorbent after the exchange. It should be noted that the contents of the various oxides are given as weight percentages relative to the total weight of the anhydrous zeolitic adsorbent material.

[0091] The Si / Al molar ratio of the zeolite present in the zeolitic adsorbent material is measured by solid-state silicon nuclear magnetic resonance (NMR) spectroscopy. For purposes of this invention, the uncertainty in the measurement of the Si / Al molar ratio is ±5%.

[0092] metal content The amount of metal present in the zeolitic adsorbent material is also obtained from X-ray fluorescence analysis as described above and is expressed as mass percentage of metal.

[0093] Metal particle size The number average diameter of the metal particles contained in the zeolite-based adsorbent material is estimated by observation using a scanning electron microscope (SEM).

[0094] To estimate the size of the metal particles in the sample, a set of images is acquired at a magnification of at least 5000x. The diameters of at least 200 particles are then measured using dedicated software, such as the Smile View software published by LoGraMi. The accuracy is on the order of 3%. The measurement of a histogram formed from the diameter measurements simultaneously allows the determination of the standard deviation σ of the distribution.

[0095] Zeolite adsorbent particle size: The volume mean diameter of the zeolite adsorbent is determined by analysis of the particle size of the aggregate sample by imaging according to ISO standard 13322-2:2006 using a conveyor belt to pass the sample in front of a camera objective.

[0096] The volume mean diameter is then calculated from the particle size by applying ISO standard 9276-2:2001. In this specification, the term "volume mean diameter" or "size" is used for zeolitic aggregates. The accuracy is about 0.01 mm for the size range of the aggregates of the present invention.

[0097] Qualitative analysis by X-ray diffraction The purity of the zeolite in the zeolitic adsorbent material is assessed by X-ray diffraction analysis, known to those skilled in the art by the acronym XRD. This determination is carried out on a Bruker brand XRD instrument.

[0098] This analysis allows differentiation of the various zeolites present in the adsorbent material, as each zeolite structure has a unique diffraction pattern defined by the positions and relative intensities of the diffraction peaks.

[0099] Before measurement, the zeolitic material is crushed and then spread and smoothed onto the sample holder by simple mechanical compression.

[0100] The conditions for acquiring the diffraction patterns on a Bruker D5000 machine are as follows:

[0101] Cu tube used at 40kV-30mA Slit size (divergence slit, scattering slit, and analysis slit) = 0.6 mm Filter: Ni Sample device rotation: 15 rpm Measurement range: 3°<2θ<50° Step: 0.02° Time count per step: 2 seconds.

[0102] The obtained diffraction patterns are interpreted using EVA software with the identification of the zeolite, aided by the ICDD PDF-2 database, 2011 release.

[0103] Microcrystallinity by Dubinin volume Dubinin volume (or micropore volume V mi ) is determined by conventional methods well known to those skilled in the art, in particular by measuring the adsorption isotherms of gases such as nitrogen, argon, oxygen, etc., at liquefaction temperatures. Nitrogen is preferably used. Prior to the adsorption measurements, the zeolite crystals of the invention are subjected to vacuum (pressure <6.7 x 10 -4 The adsorption isotherm is measured at 77 K (200 psi) at 300°C to 450°C for a period ranging from 9 to 16 hours. For example, for MFI or FAU zeolites, the nitrogen adsorption isotherm at 77 K is measured with a Micromeritics ASAP 2020 instrument, taking at least 35 measurement points at relative pressures with a P / P ratio between 0.002 and 1. The micropore volume is determined from the resulting isotherm according to the Dubinin-Raduskevitch equation by applying ISO standard 15901-3:2007. The micropore volume thus evaluated is expressed as cm of liquid adsorbent per gram of anhydrous adsorbent. 3 The measurement uncertainty is ±0.003 cm 3 .g -1 is. [Example]

[0104] The oxygen stream is withdrawn from the electrolyzer at a temperature of 50° C. The oxygen stream is pressurized to 0.8 MPa. The oxygen stream contains 3000 ppmv hydrogen and 1000 ppmv water.

[0105] The electrolytic oxygen stream to be purified is introduced into a column containing 1 liter of zeolitic adsorbent material. The contact time between the stream and the zeolitic adsorbent material is set to 10 seconds. The zeolitic adsorbent material is formed from 1 mm diameter beads obtained by agglomerating H-MFI (protonated MFI) zeolite crystals with a Si / Al ratio equal to 12.5 and a Pd content of 0.3% by weight with 20% by weight of a binder.

[0106] The purified oxygen stream collected at the column outlet is analyzed using an ionization mass spectrometer. Residual water content is confirmed using a Panametrics humidity probe. The oxygen purified in this way contains 0.3 ppmv of water, and residual hydrogen content is below the detection threshold.

Claims

1. 1. A method for purifying an oxygen stream containing water, hydrogen, and optionally nitrogen, comprising: - at least one step of contacting said oxygen stream to be purified with a zeolitic adsorbent material containing at least one metal in zerovalent metallic form or in oxidized or reduced form, and - recovery of at least one purified oxygen stream; A method comprising:

2. The method of claim 1 , wherein the purified oxygen comprises electrolytic oxygen.

3. 3. The method according to claim 1 or claim 2, wherein the oxygen to be purified comprises 60 mol% to 99.99 mol% pure oxygen, preferably 80 mol% to 99.99 mol% pure oxygen, more preferably 90 mol% to 99.99 mol% pure oxygen, even more preferentially 95 mol% to 99.99 mol% pure oxygen, typically 96.50 mol% to 99.99 mol% pure oxygen, and comprises as impurities at least water and hydrogen, and optionally nitrogen.

4. 4. The method according to any one of claims 1 to 3, wherein the at least one transition metal is selected from the metals of columns 3 to 15 of the periodic table of the elements excluding metalloids and non-metals, preferably from the metals of columns 3 to 14 of the periodic table of the elements excluding metalloids and non-metals, more preferably from palladium, platinum, silver, titanium, tin, zinc, nickel, cobalt, iron and copper, and any of these alone or as a mixture of two or more of these.

5. 5. A method according to any one of claims 1 to 4, wherein the zeolitic adsorbent material comprises at least one zeolite selected from LTA, FAU, RHO and MFI zeolites and mixtures of two or more thereof, preferably selected from FAU-type zeolites, MFI-type zeolites and mixtures thereof in all proportions and at all Si / Al ratios.

6. 6. The method of any one of claims 1 to 5, wherein the zeolitic adsorbent material comprises at least one zeolite selected from FAU-type zeolites, MFI-type zeolites, and mixtures thereof, and at least one metal in zero-valent metal form or in oxidized or reduced form selected from copper, palladium, platinum, tin, iron, and zinc, and mixtures thereof, wherein the metal can be exchanged into or impregnated into the zeolitic adsorbent material.

7. 7. A process according to any one of claims 1 to 6, wherein the oxygen stream to be purified is contacted with the zeolitic adsorbent material at a pressure of from 0.5 MPa to 5 MPa, preferably from 0.9 MPa to 5 MPa, more preferably from 1.5 MPa to 5 MPa, and at a temperature of from 10°C to 100°C, preferably from 15°C to 90°C, advantageously from 20°C to 60°C, typically from 25°C to 55°C.

8. 1. Use of a zeolitic adsorbent material comprising at least one metal in zero-valent metallic form or in oxidized or reduced form, wherein said at least one metal is selected from the metals of columns 3 to 15 of the Periodic Table of the Elements, excluding metalloids and non-metals, preferably from the metals of columns 3 to 14 of the Periodic Table of the Elements, excluding metalloids and non-metals, more preferably selected from palladium, platinum, silver, titanium, tin, zinc, nickel, cobalt, iron and copper, either alone or as a mixture of two or more thereof, for purifying an oxygen stream, in particular for purifying electrolytic oxygen.

9. Use of a purified oxygen stream obtained according to the method of any one of claims 1 to 7 as an industrial product or reagent.

10. 1. A method for preparing high purity oxygen, comprising at least the following steps: 1) electrolysis of an aqueous solution containing primarily hydrogen oxide to produce a hydrogen stream and an oxygen stream; 2) recovery of said oxygen stream from electrolysis step 1); 3) Purification of the oxygen stream recovered in step 2) by passing it through a zeolitic adsorbent material according to the method of any one of claims 1 to 7; and 4) Recovery of high purity oxygen.

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