Method for Producing a Gas Separation Membrane

Abstract

The present invention relates to a method for producing ceramic gas-separation membranes, which comprises depositing, by means of inkjet printing, water-based inks that form layers of a gas separation membrane. More specifically, the method comprises at least the following steps forming a porous support (i) compatible with a functional separation layer; depositing on the support (i), by means of inkjet printing, at least one functional separation layer (ii) formed by at least two inks, and depositing at least one porous catalytic activation layer (iii) on the functional separation layer (ii); and performing at least one heat treatment, which produces sintering. The functional separation layer (ii) is deposited in a manner to produce a surface with fadings, patterns, or combinations thereof he invention also relates to a gas separation membrane produced using the described method.

Claims

1. A method for the manufacture of ceramic gas separation membranes that comprises: deposition on a porous support (i), by means of the ink jet technique, of at least one functional separation layer (ii) consisting of at least two inks, at least one thermal treatment, which produces sintering of the layer, and deposition of at least one porous catalytic activation layer (iii) on the functional separation layer (ii).

2. The method according to claim 1, comprising at least the following steps: (a) forming of a porous support (i); compatible with a functional separation layer, (b) deposition on the support (i), by means of the ink jet technique, of at least one functional separation layer (ii) made up of at least two inks and deposition of at least one porous layer of catalytic activation (iii) on the functional separation layer (ii) and (c) at least one thermal treatment, which produces sintering, wherein the functional separation layer (ii) is deposited in a way that gives rise to a surface: with fadings, or with patterns, or with combinations of both.

3. The method according to claim 1, further comprising a step, wherein a porous catalytic layer (iv) located between the porous support (i) and the functional separation layer (ii) is deposited.

4. The method according to claim 1, further comprising a step wherein a porous compositional damping interlayer (v) is deposited between the support (i) and the porous catalytic layer (iv).

5. The method according to claim 1, further comprising the deposition of an additional non-porous layer (vi) of protection between the functional separation layer (ii) and the porous catalytic activation layer (iii).

6. The method according to claim 2, comprising applying one or more of: the porous catalytic layer (iv), when it is present, the compositional damping porous interlayer (v), when it is present the additional non-porous layer (vi), when it is present, is deposited using a technique selected from dip coating, spin coating, roller coating or screen printing; physical vapor deposition, sputtering, electron beam, atomizing; airbrushing; spraying of suspensions; and/or thermal projection (thermal spraying), including plasma spraying and spray pyrolysis, 3D printing, stereolithography, injection, ink jet printing and combinations thereof, preferably ink jet.

7. The method according to claim 1, wherein the shaping of the porous support (i) is carried out by a technique selected from uniaxial or isostatic pressing, extrusion or calendering, tape casting, conventional casting, dip coating, spin coating, roller coating or screen printing, physical vapor deposition, sputtering, electron beam, suspension spraying, and/or thermal projection (thermal spraying), including plasma spraying and spray pyrolysis, 3D printing, stereolithography, injection, inkjet printing and combinations thereof.

8. The method according to claim 1, wherein the porous support (i) comprises materials resistant to sintering temperatures and mechanically and chemically compatible with the materials of the functional separation layer (ii).

9. The method according to claim 1, wherein the constituent materials of the porous support (i) are selected from the group consisting of magnesium oxide, aluminum and magnesium spinels, cerium oxide doped with at least one lanthanide metal, zirconium oxide doped with at least one of the following elements: Y, Mg, Se or a lanthanide metal; titanium oxide, aluminum nitride, refractory alloys/superalloys, clay-based materials or silicates of aluminium, magnesium silicate, iron, titanium or alkaline or alkaline-earth elements, iron perovskites and combinations thereof.

10. The method according to claim 1, wherien the functional separation layer (ii) comprises inks that are composed of at least: (a) an inorganic solid, (b) a liquid component, and (c) a conditioning additive.

11. The method according to claim 10, wherein the functional separation layer (ii) is a non-porous layer.

12. The method according to claim 10, wherein the inorganic solids are selected from the group consisting of solids that result in a minimum ionic conductivity of the sintered functional layer (ii) of 1 mS/cm and a minimum electronic conductivity of 5 mS/cm at a temperature of 850° C.

13. The method according to claim 10, wherein the functional separation layer (ii) is a porous layer.

14. The method according to claim 1, wherein the functional separation layer (ii) has a thickness between 2 and 50 μm.

15. The method according to claim 4, wherein the set of inks that give rise to layers (iii), (iv) and (v) is composed of at least: (a) an inorganic solid, (b) a fugitive additive, (c) a liquid component, and (d) a conditioning additive; wherein components (c) and (d) are always present in the formulation of each of the constituent inks, while components (a) and (b) can both be present at the same time, or only one of them.

16. The method according to claim 4, wherein the porosity of layers (iii), (iv) and (v) is between 20 and 60% with respect to the total volume of the layer and the thickness of each layer is between 5 and 100 m.

17. The method according to claim 5, wherein the set of inks that give rise to the additional non-porous layer (vi) comprises at least: a) an inorganic solid, b) a liquid component and c) a conditioning additive.

18. The method according to claim 5, wherein each of the layers (ii), (iii), (iv), (v) and (vi), after sintering, comprises at least 2 different inorganic crystalline phases, selected from the group consisting of fluorite, perovskite, spinel, pyrochlore and combinations thereof.

19. The method according to claim 5, comprising generating a fading or a pattern after an application or identical applications, in layers (ii), (iii), (iv) and (v) and (vi) after a thermal treatment that has a distribution in the different crystalline phases and/or porosity selected from the group consisting of 2D chessboard, mosaic with interconnectivity of phases in section, fractal pattern, spiral pattern and combinations thereof.

20. The method for the manufacture of ceramic gas separation membranes, according to claim 5, wherein the fading or pattern that is generated, after more than one application with a different pattern, in layers (ii), (iii), (iv) and (v), after heat treatment, is a fading with 3D architectures selected from the group consisting of conical, pyramidal, spiral and combinations of them.

21. A ceramic membrane obtained by the method comprising: deposition on a porous support (i), by means of the ink jet technique, of at least one functional separation layer (ii) consisting of at least two inks, at least one thermal treatment, which produces sintering of the layer, and deposition of at least one porous catalytic activation layer (iii) on the functional separation layer (ii).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0174] FIG. 1 shows a simplified representation of a membrane with: (i) a porous support, (ii) a separating functional separation layer;

[0175] FIG. 2 shows a simplified representation of a membrane with (i) a porous support, (iv) an intermediate porous catalytic layer, (ii) a separating functional layer and (iii) an upper porous catalytic activation layer;

[0176] FIG. 3 shows a simplified representation of a membrane with: [0177] (i) a porous support, [0178] (v) a porous compositional damping interlayer, (iv) a porous catalytic layer, (ii) a non-porous functional separation layer, and (iii) an upper catalytic activation layer;

[0179] FIG. 4 shows a schematic of a membrane in which the architecture and sequence between (i), (ii), (iii), (iv), (v) and (vi) are presented;

[0180] FIG. 5 shows a) representation of the separation of hydrogen through dense membranes based on ceramics capable of transporting protons and electron carriers at high temperature, b) representation of the separation of oxygen through dense membranes based on ceramics capable of transport of oxygen ions and electron carriers at high temperature;

[0181] FIG. 6 shows a scanning electron microscope image of a cross-section of an oxygen-permeable ceramic membrane exhibiting (i) a porous support, (iv) a porous catalytic layer, (ii) a non-porous functional separation layer;

[0182] FIG. 7 shows a scanning electron microscopy image of a ceramic membrane permeable to oxygen that presents components (i), (ii), (iii) and (iv), the last three layers being made up of a material composed of two crystalline phases, one that conducts mainly oxygen ions and another that conducts mainly electron carriers;

[0183] FIG. 8 shows design examples of functional layers made with inkjet printing technology (inkjet. a) Electric conductive lines on ionic conductive matrix; b) Arrangement in a chessboard form of different mixed conductors; c-d-e-f) Fractal arrangement of different mixed conductors;

[0184] FIG. 9 shows an example of multilayer design with pyramidal 3D architecture;

[0185] FIG. 10 shows scanning electron microscope image of a cross section of an oxygen-permeable ionic ceramic membrane prepared by inkjet technology, showing a 3-stage fading of the dense functional layer (ii) obtained by mixing two different crystalline phases; and FIG. 11 shows scanning electron microscope images of a cross section of an oxygen-permeable ionic ceramic membrane prepared by inkjet technology, wherein a 3D pattern is observed in the location of the grains of two different crystalline phases (spinel and fluorite) along of the axis parallel to the printing plane.

[0186] The present invention is illustrated by the following examples which are not intended to be limiting thereof.

DETAILED DESCRIPTION OF THE INVENTION

[0187] The various features and advantageous details of the subject matter disclosed herein are explained more fully with reference to the non-limiting embodiments described in detail in the following description.

Examples

Example 1

[0188] Preparation of Materials and Inks On a porous advanced ceramic (porous support (i) of yttrium-doped zirconium oxide with a PMMA pore former that has undergone a heat treatment of 1000° C. (2h), ramp 1° C./min), which acts as a support for the membrane and does not present catalytic activity, inks T1 and T2 have been deposited, which originate the porous (iv) and dense (ii) layers after sintering, respectively. Both printable inks are obtained from the combination of three inks (A, B and C).

[0189] The liquid components used for inks A, B and C have been water and long chain glycol. As conditioning agents (dispersants, preservatives, binders, surfactants, etc.) a system of specific additives for water-based work has been used, which made it possible to regulate the properties of the ink, facilitating its application in high thicknesses (required for the application) without adherence defects to the substrate, cracks or formation of surface irregularities, achieving uniform and smooth layers on the ceramic support.

[0190] As examples of dispersants or mixtures thereof, there are on the market, produced and distributed by LUBRIZOL, such as Solsperse 13940, Solsperse 36000, Solsperse 32500, Solsperse 28000, Solsperse 19000, Solsperse 16000, Solsperse 39000 or their respective assigned codispersants such as Solsperse 22000 and 5000.

[0191] Other additives: glycols such as diethylene glycol, glycerin, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,5-pentanediol, 1,6-hexanediol, polycarboxylic acids Preservative: they can be antioxidants such as ascorbic acid.

[0192] Examples of binders: emulsified polymers such as butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and polyglycols, triethanolamine, methylpyrrolidone, polyvinylpyrrolidone.

[0193] Conventional surfactants: anionic and/or nonionic emulsifiers such as, for example, ammonium or alkali metal salts of alkyl, aryl, alkylaryl sulfates, sulfonates or phosphates; alkyl sulfonic acids; sulfosuccinate salts; fatty acids; ethylenically unsaturated surface active monomers, and ethoxylated alcohols or phenols.

[0194] Antifoams can be, for example, block copolymers based on ethylene and propylene oxide, e.g. Pluronic 127, Pluronic 123, Pluronic L61.

[0195] The composition of each of the inks A, B and C is as follows:

[0196] Ink A has in composition an organic solid with a high specific surface area, the composition being as follows:

TABLE-US-00001 TABLE 1 Weight percentage with respect to the Ink A total weight of the ink Organic Solid (PMMA) 10-30 Water 15-35 Glycols PEG 200 (polyethylene glycol 200), 15-35 DEG(diethylene glycol) Dispersant: Acrylic polymer  2-20 Defoamer: Polymers and copolymers of alkoxanes 0.1-2.sup.  Surfactant: Siloxane modified with polyether 0.05-2   Preservative: Isothiazolone derivatives solution 0.01-0.05 [0197] Ink B has a high-density ceramic oxide as its composition, its composition being as

TABLE-US-00002 TABLE 2 Weight percentage with respect to the Ink B total weight of the ink Ceramic oxide 30-45 Glycols 15-35 Water 15-35 Dispersant: Acrylic polymer  1-20 Defoamer: Polymers and copolymers of alkoxanes 0.1-2.sup.  Surfactant: Siloxane modified with polyether 0.05-2   Preservative: Isothiazolone derivatives solution 0.01-0.05

Solution

[0198] Finally, ink C has in composition a pigment based on metal oxides -electronic conductive crystalline phase-of low density, its composition being as follows:

TABLE-US-00003 TABLE 3 Weight percentage with respect to the Ink C total weight of the ink Pigment 30-45 Glycols PEG 200 (polyethylene glycol 200), 15-35 DEG (diethylene glyco) Water 15-35 Dispersant: Acrylic polymer  1-20 Defoamer: Polymers and copolymers of alkoxanes 0.1-2.sup.  Surfactant: Siloxane modified with polyether 0.05-2   Preservative: Isothiazolone derivatives solution 0.01-0.05

[0199] Each of these inks has been prepared using a microball mill commonly used in the manufacture of inkjet inks. To obtain the catalytic inks T1 and T2, the established amount of each of the preparations A, B and C has been dosed, in the percentages shown in Table 4, and an integration and homogenization process has been carried out (for example, agitation and grinding with ceramic micro-balls).

TABLE-US-00004 TABLE 4 Percentage by weight of the preparations that constitute the catalytic inks Catalitic ink A B C T1- porous catalitic layer (iv) 15-25 15-25 45-60 T2-dense functional separation (ii) — 20-30 70-80

[0200] Below, Table 5 specifies the approximate composition of both functional inks, as well as their main characteristics:

TABLE-US-00005 TABLE 5 Composition and properties of catalytic inks T1 and T2 COMPOSITION Solid content 25-45% respect to the total weight of the composition Liquid content 25-70% Aditive content  2-20% PROPERTIES Density 1.15-1.40 g/cm.sup.3 Viscosity under Shot Conditions 13-18 cP (rheometer) Particle size D.sub.99 0.8-1.5 μm Surface tension 26-33 mN/m

Inkjet Application of the Functional Layers

[0201] The prepared inks were deposited on flat supports made of advanced zirconium oxide ceramics doped with 3% molar of yttrium oxide that have high porosity (40%) and permeability to the passage of gases as a result of the combustion of the fugitive agent (microspheres of PMMA) present in the formulation in a previous thermal treatment at 1100° C.

[0202] These inks can be applied with different piezoelectric heads designed to support water as the main solvent, such as Dimatix 1024 M, L, HF, PQRL. Also the new heads from Seiko and Kiocera are suitable for these inks.

[0203] In this way it is possible to apply an amount of ink around 100 gr/m.sup.2 per head bar.

[0204] Taking into account that currently both, single pass machines and plotters, can install up to 12 bars, it is possible to get an idea of the amount of ink that can be downloaded.

Example 2

[0205] Deposition Process (Machinery, Heads, Deposition Parameters, Passes, Etc.) First, the T1 ink was applied to the available ceramic substrate using a Dimatix HF head.

[0206] In total, 225 g/m.sup.2 were applied, for which it was necessary to make a total of 3 passes of 75 g/m.sup.2 each.

[0207] Next, a total of 375 g/m.sup.2 of T2 ink was applied, for which it was necessary to make a total of 5 passes of 75 g/m.sup.2 each. After a drying process at 100° C., a heat treatment is carried out at 1450° C., obtaining a sintered membrane, which was finally deposited using T1 ink (to obtain the catalytic layer (iii)) and after a drying, it is sintered at 1100° C.

Example 3

[0208] Sample prepared in the same way as that described in example 2, but to which an aqueous solution of Pr and Ce nitrate, 1M, was infiltrated into the porous substrate. The membrane obtained is in accordance with the present invention and has a porous support (i), a functional non-porous separation layer about 100 μm thick (ii) and an upper porous catalytic activation layer (iii), according to the scheme shown in FIG. 2.

[0209] To evaluate the oxygen separation properties of the compounds under study, an experimental set-up made of quartz is available, in which one can analyze the behavior of different ceramic membranes.

[0210] The quartz assembly consists of a tube with two chambers separated by a ceramic membrane, with no point of communication between the two chambers due to the density (absence of porosity) of the membrane and the sealing made with O-rings.

[0211] On one side an oxygen-rich stream is fed, while on the other side a carrier gas is circulated or a vacuum is induced. This difference in oxygen content conditions serves as the driving force for oxygen diffusion to occur from the feed-reject side towards the permeate side. Using a gas chromatograph to quantify the oxygen content in the permeate stream, the flow of oxygen that permeates through the membrane under different conditions is determined, oxygen content in the feed chamber and aggressive atmospheres in the permeate (presence of CO.sub.2 and SO.sub.2).

[0212] Oxygen permeation was studied on the membrane described above. Permeation tests and catalytic studies were carried out on disc-shaped membranes with a diameter of 15 mm and a thickness of approximately 1 mm. The reaction temperature is controlled by a thermocouple close to the membrane. The permeate gas stream was analyzed using a Varian CP-4900 micro-CG equipped with three analysis modules: Molsieve5A, PoraPlot-Q and CP-Sil.

[0213] Table 6 shows the oxygen permeation obtained in milliliters (normal conditions) per minute and square centimeter (Nml.Math.min.sup.−1 cm.sup.−2) as a function of temperature. The results show that the membrane according to the present invention has a much higher oxygen permeation than a membrane prepared by uniaxial pressing of the same composition as layer (ii) of the membrane prepared according to the present invention and sintered at 1450° C.

TABLE-US-00006 TABLE 6 Example 950° C. 900° C. 850° C. 800° C. 700° C. Ink jet — — 0.45 0.2 0.075 Conventional monolitic 0.016 0.005 0.008 — —