CS257751B2 - Multicomponent membrane for gas separation - Google Patents

Abstract

Multicomponent membranes for gas separation are disclosed which are effective for separating at least one gas from gaseous mixtures by permeation wherein the multicomponent membranes are comprised of a coating in occluding contact with a porous separation membrane. The multicomponent membranes advantageously exhibit less resistance to permeate. gas flow for the at least one gas than for at least one remaining gas in the gaseous mixture. For at least one pair of gases the separation factor of the multicomponent membrane is significantly greater than the determined intrinsic separation factor of the material of the coating. Processes and apparatus for gas separation utilizing the multicomponent membranes are also disclosed.

Description

The invention relates to a multi-component gas separation membrane, in particular for the separation of gases containing hydrogen, helium, ammonia, carbon monoxide, carbon dioxide, nitrogen, argon, sulfur hexafluoride, methane and ethane, which consists of a coating material and a porous support.

Separation processes, including those in which the concentration of the desired component is increased and in which at least one desired gas is separated from the gas mixture, are particularly important, especially given the fact that stocks of chemical raw materials are not inexhaustible. In view of the above, there is an increasing need in technical practice for the separation of one or more gases from a gas mixture for further use in the production process. Numerous methods of selectively separating one or more gases from gas mixtures by means of separation membranes are known in the art. In order to achieve selective separation, the membrane must exhibit less resistance to the passage of one or more gases to the passage of at least one other gas contained in the mixture. In this selective separation, a preferential reduction or increase in the concentration of one or more desired gases in the mixture relative to the at least one other gas is thereby obtained, and thus a product having a different ratio of one or more desired gases to at least one other gas than the original gas mixture. However, to the selective separation of the one or more desired gases by using separation membranes have been utilized in industrial scale membrane should be capable of withstanding not only the conditions to which they may be subjected _t during the separating "process, ATE must also permit adequate selective separation of the one or more desired gases at a sufficiently high filtration rate per unit surface area of the membrane to make economically advantageous to use the separation process. Separation membranes, which exhibit relatively high values of selectivity of separation but unacceptable low values of filtration rate, require such large surface areas of the separation membrane that the use of these membranes would be unacceptable for industrial reasons in industrial conditions. Similarly, separation membranes that exhibit high filtration rates but low selectivity selectivity are also industrially unusable. Thus, in the development of separation membranes, the aim is not only to develop a measured selective membrane for separating one or more desired gases from the gas mixture, but also to achieve a sufficiently high

2377S1 notes of filtration rate so that the use of these separation membranes is also possible on an industrial scale for economic reasons.

Generally, gas passage through a membrane is typically effected by passing through pores, i.e., continuous fluid passageways that connect the inlet and outlet surfaces of the membrane (which pores may or may not be suitable for gas separation by Knudsen or diffusion). According to another mechanism, in the present view of membrane theory, gas passage through the membrane can be accomplished by the interaction of gas with the membrane material. In the latter mechanism, it is believed that as gas passes through the membrane, gas dissolves in the membrane material and diffuses gas through the membrane. The gas permeability constant is then given as a result of the gas solubility and diffusivity through the membrane. Thus, the membrane material has its permeability constant for the passage of the gas with the membrane material. The gas filtration rate, i.e. the gas flow through the membrane, depends on the permeability constant, but is also influenced by other factors such as the membrane thickness, the physical nature of the membrane, the differential pressure of the filtered gas through the membrane, the temperature, etc.

To address the particular problems encountered in performing separation operations, various modifications of membranes used for separating liquids have been developed to date. In the following, specific modifications of the membranes used for liquid separation and solving specific problems associated with such separation will be described, the description of which will need to be addressed in the design of these membranes, and the gas separation problems will be discussed. For example, cellulosic membranes which have been developed and used for desalination of water may be referred to generally as "dense" or "compact" membranes. These dense or compact membranes are membranes which are substantially free of pores, i.e. both membrane surfaces have no connection through channels through which fluid can flow and are substantially free of voids, i.e., they are not in the membrane material itself. cavities containing the membrane material. In the case of compact membranes, either of the two surfaces is suitable as an inlet surface, since the properties of the compact membrane are the same regardless of the side of the surface, i.e. the membrane is symmetrical. Since the membrane is substantially the same throughout its structure, it falls within the definition of isotropic membranes. Although some of these compact membranes are very selective, one of their major drawbacks is the low filtration rate due to the relatively higher membrane density. Therefore, it is uneconomical to build a plant for desalination of larger amounts of water using compact membranes. In order to increase the filtration rate of the membranes used to separate liquids, for example, fillers have been added to these membranes to adjust the porosity and make the membranes as thin as possible, thereby increasing the filtration rate. Although an improvement in the filtration rate has been achieved to some extent, these improved results have usually been achieved to the detriment of the selectivity of special membranes.

In an effort to improve membrane performance, it has been proposed to produce a modified membrane for desalting water from cellulose acetate, see Loeb et al. U.S. Pat. No. 3,133,132. In this method, a thin film is first formed by casting a cellulose acetate solution and then a dense membrane surface is formed on the film, which can be accomplished by various techniques such as solvent evaporation and subsequent dipping cold water. The formation of these dense surface membranes usually involves a final swelling process in hot water. Membranes produced by the method of Loeb et al. they are composed of two different layers, but made of the same cellulose acetate material, i. a thin dense, semi-permeable surface layer; and a less dense, non-selective carrier layer that contains cavities. Since these membranes do not have substantially the same density throughout their structure, they fall within the definition of anisotropic membranes. Because of these different layers and the different properties of the individual parts of the membrane, which can be observed depending on which side of the membrane the salt solution to be treated is supplied to, the membranes of Loeb et al. characterized as asymmetric membranes.

These asymmetric dense-coated membranes have, for example, been shown in practical desalination tests to have a higher filtration rate than older types of compact membranes. The improvement in the filtration rate of the Loeb-type membranes has been attributed to a reduction in the thickness of the dense selective layer. The less dense layer in this membrane forms a sufficiently strong structural support, thereby preventing the membrane from bursting in operations carried out under pressure while having low resistance to the filtrate flow. Thus, the separation takes place substantially on the dense surface layer, the primary function of the less dense carrier layer being to provide a physical carrier for the dense surface layer. However, in these L-Oeb-type membranes, these less dense carrier layers are often compacted by the pressures occurring during desalination of water.

Under these conditions, the less dense carrier layer loses some of its original volume (i.e., the volume that is formed by the cavities in the membrane), thereby preventing free flow of filtrate on the outlet side of the dense surface layer, resulting in a reduced filtration rate. Moreover, the acetate-cellulose membranes developed by Loeb et al. Are clogged and subject to various chemical degradations. Attention has therefore been paid to the development of Loeb-type membranes, but from materials other than cellulose acetate, in order to achieve better structural properties and increase the chemical resistance of the membranes. The processing of the Loeb polymer materials to obtain a one-component membrane that exhibits good selectivity and good filtration rate has proven extremely difficult. Most experiments have resulted in membranes that are either porous, i.e., having channels in a dense surface layer for fluid flow through which fluid separation cannot be performed, or which have a dense surface layer too thick to make the filtration rates achievable in practice . Moreover, these asymmetric membranes usually fail in cases where liquid separation is performed by reverse osmosis. As will be discussed below, it is even more difficult to obtain Loeb-type membranes having good selectivity and filtration rate for gas separation.

Further development of obtaining suitable separation membranes for water desalination and separation of liquids, such as organic substances from liquids, has resulted in composite membranes containing a porous carrier through which liquid can easily pass through the presence of flow channels but which is strong enough to withstand operating conditions of the separation process, and a thin semipermeable membrane that is supported on the support. These composite membranes include so-called " dynamically formed " membranes which are manufactured by continuously depositing polymeric material from the feed solution onto a porous carrier in the form of a film. This continuous deposition is necessary because the polymer film is introduced into the pores and passes through the porous substrate and therefore needs to be replenished. In addition, the film of polymeric material is usually sufficiently soluble in the divided liquid composition so that it also undergoes lateral erosion, i.e., washout from the carrier.

Composite desalting membranes are also known from the prior art, which are manufactured such that the porous support is provided with a substantially rigid diffusion or separation membrane. For example, U.S. Pat. No. 3,676,203 to Sachs et al. Discloses an acrylic acid-based separation membrane on a porous support such as cellulose acetate, polysulfone, etc. Thickness of the separation membrane. it is relatively large, for example up to 60 nm, so that the separation membrane is sufficiently strong and does not tend to penetrate or crack on the pores of the porous carrier. Other suggestions include the use of an anisotropic carrier whose surface is denser as a direct carrier of a separation membrane, see, for example, Cabasso et al., Research and Development by NS-1 and Related Polysulfone Hollow Fibers for Reverse Osmosis Desalination of Seawater, Gulf Research Institute, July 1975, publication National Technical Information Service, US Department of Commerce, No. PB 248 666. Cabasso et al. discloses composite water stripping membranes which consist of anisotropic polysulfone hollow fibers which are coated, for example, with polyethyleneimine which is crosslinked in situ, or with furfuryl alcohol polymerized in situ, to provide a superimposed separation membrane. Another procedure for obtaining reverse osmotic membranes is disclosed in U.S. Patent 3,556,305 to Shorr. This patent discloses three-component reverse osmosis separation membranes consisting of anisotropic porous material, an ultra-thin adhesive layer on the porous substrate, and a thin semipermeable membrane bound to the substrate by the adhesive layer. These ultra-thin semi-opaque oral membranes are often produced separately when bonded to the porous carrier material, with the separately produced ultrathin membrane and porous carrier then joining surfaces to one another.

Other types of membranes that are used to process liquids are so-called " ultrafiltration membranes in which pores of a desired diameter are formed. Sufficiently small molecules can pass through these pores, while larger or larger molecules are retained on the upstream side of the membrane. Examples of various types of ultrafiltration membranes are disclosed in U.S. Patent 3,556,992 to Massucco. These membranes have an anisotropic carrier and a gel is irreversibly pressed onto the carrier to obtain membranes having a suitable pore size for separating alkali hydroxides from hemicellulose, the ultrafiltration being carried out on a gel.

The foregoing analysis of the prior art relates to membranes for separating liquid from a liquid mixture, such as water desalination. Recently, the development of separation membranes suitable for separating gas from a gas mixture has gained importance. The passage of gases through the separation membranes has been subjected to various studies, and it has been noted that gas separation membranes have not been developed which have both a high filtration rate and a useful selectivity in gas separation, at least not for industrial use. In the following description illustrate specific modifications of membranes designed for gas separation, from which ^one can describe a sense of the problems in the art and thus of relevance to the present invention.

In the field of gas separation, efforts have first been made to exploit the knowledge gained in developing membranes for separating liquids from liquid mixtures. However, there are many different conditions when developing suitable separation membranes for gaseous systems as compared to developing suitable membranes for liquid systems. For example, the presence of small pores in the membrane may not adversely affect the performance of the liquid separation membrane, such as water desalination, due to the absorption and swelling of the membrane and the high viscosity and high cohesive properties of the liquids.

Since gases have extremely low absorption, viscosity and cohesive properties, there is no obstacle to the easy penetration of pores in such a membrane, resulting in little, if any, gas separation. A very important difference between liquids and gases that can affect selective partitioning through membranes is generally lower solubility of the gases in the membranes compared to the solubility of the liquids in these membranes, resulting in lower permeability constants for gases compared to the permeability constants for liquids. Other differences between liquids and gases that may affect selective separation by gas filtration through the membrane are density and internal pressure, the effect of temperature on viscosity, surface tension, and the degree of structure of the material structure.

It is known that materials that exhibit good gas separation properties often have lower permeability constants as compared to materials that have poor gas separation properties. In general, efforts in the art have been directed to obtaining a material for forming a gas separation membrane in as thin a form as possible, since low permeability must be considered to achieve an adequate filtration rate, with the membrane as preferably as possible. without pores so that the gases would pass through the membrane by interaction with the membrane material. One possible approach to the development of separation membranes suitable for gas systems consists in obtaining a composite membrane that superimposes on it an anisotropic porous support, where the superimposed membrane provides the desired separation, i.e. the superimposed membrane is semipermeable. The superimposed membranes are preferably thin enough; ultra-thin, thereby obtaining filtration rate values that are usable on an industrial scale. The main function of the porous support is to form the substrate and protect the superimposed membrane against damage to the fine, thin superimposed structure. Suitable carriers have a low resistance to the passage of the filtrate when selectively separating the filtered component from the mixture to be treated on this superimposed membrane. These carriers are preferably porous, since such a structure has a low resistance to the filtrate passing through and is still sufficiently supportive, i.e., having a pore size sufficiently small to prevent rupture of the superimposed membrane under partitioning conditions. Examples of gas separation membranes with a superimposed membrane on a porous support are disclosed in U.S. Patent 3,616,607 to Klass et al., U.S. Patent 3,657,113 to Stancell et al. and U.S. Patent 3,775,303 to Yasuda.

However, these composite gas separation membranes have drawbacks. For example, U.S. Patent No. 3,980,456 to Browall discloses the production of composite membrane layers for separating oxygen from air, consisting of a carrier comprised of a microporous polycarbonate sheet and a separately manufactured, i.e., a " a pre-made, superimposed ultra-thin separation membrane consisting of 80 percent polyphenylene oxide and 20 percent organopolysiloxane polycarbonate copolymer. Elimination of the presence of impurities in the form of extremely small particles; According to Browall, particles of a particle size below about 300 nm from the manufacturing sphere are practically impossible or impossible. These fine particles can be deposited under or between the preformed ultrathin membrane layers and, due to their large dimensions compared to ultrathin membranes, the ultrathin membrane is punctured. These cracks then reduce membrane efficiency. The Browall patent discloses the use of a preformed organosiloxanopolycarbonate copolymer as a sealing material for these ultra-thin membranes. the copolymer sealing the cracks caused by fine particles. Browal also discloses the use of a pre-fabricated ru layer as an adhesive between an ultra-thin membrane and a porous polycarbonate support. The composite membranes of Broiwal are then complex in terms of both materials and preparation methods.

From the foregoing, it is apparent that suitable anisotropic gas separation membranes have not yet been developed, except for superimposed membranes, which provide selective separation, and which exhibit a sufficient filtration rate and ensure separation selectivity for general industrial use. Furthermore, it is apparent from the above that composite gas separation membranes having a superimposed membrane to provide selective separation have achieved only slight or slight improvements in efficiency, and have proven unsuitable for various industrial scale purposes. In addition, although superimposed membranes are preferably ultra-thin in order to achieve the desired selectivity in separation, superposed membranes can significantly reduce the flow of filtered gas through the composite membrane as compared to the porous flow rate of a porous carrier that does not have a superposed membrane thereon.

The principle of a multi-component gas separation membrane consisting of a coating material which is in contact with the porous support consists in that the porous support is a porous separation membrane having a thickness ranging from 200 to 500 microns and having a volume of 10 to 10 microns. 80% formed by pores, and which consists of polysulfone

wherein n has a value of from 50 to 80, having at least about 35% greater than the determined internal separation factor of the coating material relative to at least one gas pair, and a coating material of 0.001 to 50 micrometer thick, consisting of a polysiloxane having with respect to one gas pair, the determined internal separation factor smaller than the determined internal separation factor of the multicomponent membrane is in occlusive contact with the porous separation membrane.

The multicomponent gas separation membrane according to the present invention consists of a coating which is in occlusive contact with the porous separation membrane, the separation properties of the multicomponent membrane being in principle determined by the porous separation membrane and not by the coating material. These multi-component membranes for separating at least one gas from the gas mixture have the desired selectivity while still exhibiting a useful filtration rate for industrial use. According to the present invention, multi-component membranes are obtained which can be made of different materials and thus provide greater freedom in the selection of suitable materials compared to the prior art, which is very advantageous in the actual gas separation. According to the present invention, multi-component membranes can be obtained from which the desired combination of filtration rate and selectivity can be achieved by membrane structure, production methods and combinations of constituents forming the membrane. In this way, it is possible to use a material having a high selectivity of separation but a relatively low permeability constant to obtain multi-component membranes having a desired filtration rate and, in addition, the desired selectivity of separation. Furthermore, the membranes of the present invention are relatively insensitive to the influence of contaminants (i.e. fine particles) during their manufacture, which previously caused difficulties in manufacturing composite membranes consisting of a pre-fabricated ultra-thin separation membrane superimposed on a carrier. The use of adhesives in the manufacture of the multi-component membranes of the present invention is preferably not necessary. It follows from the foregoing that the process for manufacturing the multi-component membrane of the present invention is not complicated and complicated.

The multicomponent membranes of the present invention can be made to have sufficiently high structural strength, stiffness, abrasion resistance, and chemical resistance, while at the same time exhibiting advantageous filtering speed and selectivity of separation that can be utilized on an industrial scale. The multi-component membranes of the present invention are further advantageous in that they are easy to handle, for example, few; susceptible to static electric forces, have little adhesion to other multi-component membranes occurring in their vicinity, and the like.

According to the present invention, the multi-component gas separation membranes consist of a porous separation membrane with an inlet and outlet surface and a covering material which is in contact with the porous separation membrane. The porous separation membrane has a substantially uniform composition, or uniform distribution of material throughout its structure, i.e. the porous separation membrane is substantially homogeneous. The porous separation membrane material exhibits the ability to selectively filter at least one gas from the gas mixture as compared to at least one other gas of the gas mixture, and this porous separation membrane is therefore defined as a "separation" membrane. By the above characterization of the separation membrane, which is said to be porous, it is meant that this membrane has continuous channels for the flow of gas, i. pores that connect the inlet and outlet surfaces of the membrane to each other. These continuous continuous ducts, if sufficient and large enough, allow substantially the entire gas mixture to flow through the porous separation membrane with little, if any, separation that would result from interaction with the porous separation membrane material. . However, according to the present invention, advantageous multi-component membranes have been developed which, due to the interaction with the material of the poirous separation membrane, can achieve an increased separation of at least one gas from the gas mixture compared to the separation on the porous separation membrane itself.

The multicomponent membrane according to the invention is formed, as already mentioned, by a porous separation membrane and a coating, both of which are in a special relationship with each other.

Some characteristics of this relationship can be appropriately illustrated by the relative separation factors relating to the two gases, the porous separation membrane, the coating, and the multi-component membrane as a whole. The separation factor [a _and ^b ] for the membrane and given gas pair a and b is defined as the ratio of the permeability constant (P _fI ) of the gas membrane to the permeability constant (P _b ) for the gas b. The separation factor is also equal to the permeability ratio [P _a / 1] membrane of thickness 1 for gas and gas mixtures to permeability of the same gas membrane b [Pi / 1), where permeability for> given gas is the volume of gas at standard temperature and pressure (STP), which passes through one square centimeter of membrane surface area per second at a partial pressure drop of 1.3 kPa per unit thickness of the membrane and is expressed as P = cm ³ / cm ² . 1.3 kPa.

In practice, the separation factor for a given gas pair and for a given membrane is determined using a variety of methods, in which sufficient information is obtained to calculate permeability or permeability constants for each of the gas pairs. Some of the many methods that are suitable for determining permeability constants, permeability, and separation factor are described by Hwang et al. in Techniques of Chemistry, Volume VII, Membranes in Separation, John Wiley and Sons, 1975, Chap. 12, pp. 296-322.

By internal separation factor in the present description is meant the separation factor of a material which has no gas flow channels through the material and is the highest achievable separation factor for the material. Such material can be referred to as continuous or non-porous material. The intrinsic separation factor of the material can be approximately determined by measuring the separation factor of the compact membrane from the material. However, when determining the internal separation factor, some problems may arise, for example related to defects that occur in the manufacture of the compact membrane, such as the presence of pores, the presence of fine particles in the compact membrane, the indeterminate molecular arrangement resulting from changes in membrane production. , etc. It follows from the above that the determined internal separation factor may have a value lower than the actual value of the internal separation factor. Thus, the term " determined in the intrinsic separation factor ⁴ " used in the description of the present invention refers to the separation factor of the dry compact membrane from the material.

The multi-component gas separation membranes of the present invention exhibit, with respect to at least one gas pair, a separation factor that is substantially higher than the determined internal separation factor of the coating material in occlusive contact with the porous separation membrane. The term "significantly higher ⁴⁴ when placing interrelationships separation factor of the multicomponent membrane and the determined intrinsic separation factor of the coating material is meant that the difference in separation factor is large, for example, usually at least about 35 ° / o higher. By slip contact ⁴ is meant such contact of the coating with the porous separation membrane in the resulting multicomponent membrane that the proportion of gases passing through the porous separation membrane material to the proportion of gases passing through the pores is greater than that in the porous separation membrane itself . Thus, this contact is of such a kind that in this multicomponent membrane, during the gas separation, the material of the porous separation membrane to the separation factor of the final multicomponent membrane for at least one gas pair as compared to the separation which occurs using the porous separation membrane alone. With respect to said at least one gas pair, the separation factor exhibited by the multicomponent membrane will then be greater than the separation factor exhibited by the porous ceparation membrane itself. Addition. with respect to said at least one gas pair, the porous separation membrane material exhibits a greater determined internal separation factor than the determined internal separation factor of the coating material. It should also be noted that with respect to at least one gas vapor, the separation factor exhibited by the multicomponent membrane is usually equal to or less than the determined internal separation factor of the porous separation membrane material. Regardless of the intended use of a multi-component gas separation membrane, the separation factor relationships may be demonstrated on at least one pair of gases, one of the group consisting of helium, hydrogen, ammonia and carbon dioxide, and the other of the group comprising carbon monoxide, nitrogen, argon, sulfur hexafluoride, methane and ethane. The interrelation of separation factors in some multicomponent membranes of the present invention can be demonstrated on a pair of gases wherein one of the gases is carbon dioxide and the other is selected from hydrogen, helium, and ammonia, or the gases are ammonia and the other gas is selected skupinyθ groups including carbon dioxide, hydrogen and helium.

According to the present invention, it is desirable that the multi-component membrane of the mole is at least 35% greater, preferably at least 50% greater, and in some cases at least 100% greater than the determined internal separation factor for at least one gas pair. coating material. Often, a separation factor is selected when referring to at least one of the gas pairs mentioned above, for said multi-component membrane at least 50 or 100 percent greater than the porous separation membrane factor of the separator.

The multicomponent membrane of the present invention, as mentioned above, comprises a coating that is in occlusive contact with the porous membrane of a material that is selective for filtering at least one gas from the gas mixture relative to the at least one other gas from the gas mixture. Said porous separation membrane has a considerable void volume, wherein the final multicomponent membrane has a separation factor substantially greater than the determined internal separation factor of the coating material relative to at least one gas pair. There are voids within the porous separation membrane that are not occupied by the porous separation membrane material. It follows that, when these voids are formed, the density of the porous separation membrane is less than the density of the porous separation membrane material. If it is stated that the void volume is significant, this means that there is a sufficiently large void volume volume in the porous separation membrane, e.g. at least 5 volume percent voids, thereby observing a noticeable increase in membrane filtration rate compared to has a compact membrane of the same material and thickness. The void volume is preferably up to about 90 percent, practically about 10 to 80 percent, suitably about 20 or 30 to 70 percent, based on the surface volume, i.e. the volume given by the external dimensions of the porous separation membrane. One method for determining the void volume of a porous separation membrane is to compare the density with the volume of the porous separation membrane material itself, and this volume corresponds to a membrane having the same physical outer dimensions and the same configuration as the porous separation membrane. Thus, the openings and hollow channels of the porous separation membrane do not affect the density of the porous separation membrane.

The density of the porous separation membrane may be substantially the same throughout its thickness, that is, the material is isotropic, or the porous separation membrane may be characterized in that it has at least one relatively dense region in its thickness that acts as a gas flow barrier at passing through the porous separation membrane, that is, the porous membrane is anisotropic. The coating is preferably in ocular contact with the relatively dense region of the aisetropic porous separation membrane. Since the relatively dense region can be porous, it can easily be made quite thin. compared to making a compact membrane of the same thickness. The use of porous separation membranes having relatively dense regions that are thin provides increased flow through the multi-component membrane.

The multicomponent membranes of the present invention consisting of a coating in occlusive contact with the porous separation membrane are of a material that is selective for filtering at least one gas of the gas mixture compared to at least one or more other gases of the gas mixture, the coating being applied using and, in respect of at least one gas pair, the multicomponent membrane exhibits a separation factor substantially greater than the determined intrinsic separation factor of the coating material.

A substance that is applied to a porous separating membrane is designated as essentially a liquid because it is meant a substance that is unable to maintain its shape in the absence of an external carrier. The coating material may be a liquid or a substance dissolved or suspended in the liquid solvent in the form of finely separated particles (e.g. of a colloidal size) to provide a substantially liquid substance for application to a porous separation membrane. According to the invention, it is preferred that the coating material or coating material in a liquid solvent is wettable, i.e., if it tends to adhere to the porous separation membrane material. Thus, contact of the coating with the porous separation membrane is greatly facilitated. The use of substantially liquid substances to produce a coating of a porous separation membrane permits the use of simpler methods compared to methods used to produce composite membranes from separately manufactured solid materials of the prior art. In addition, a wide range of different materials and application methods can be used for the coating, which can be adapted to different porous separation membrane configurations.

As already mentioned, the multicomponent membrane according to the invention consists of a coating which is in occlusive contact with a porous separation membrane made of polysulfone, the multicomponent membrane having a separation factor substantially greater than the determined internal separation factor of the coating material. The multi-component membrane has, in an alternative embodiment, a coating in occlusive contact with the porous hollow fiber separation membrane, wherein the membrane material is selective for filtering at least one gas of the gas mixture against one or more of the gas of the gas mixture. With respect to the at least one gas pair, the multicomponent membrane exhibits a separation factor substantially greater than the determined internal separation factor of the coating material. In hollow fibers, the outer surface may be the entry nobo exit surface of the porous separation membrane, and the inner surface may also be the entry or exit surface. The hollow fibers are advantageous in that they facilitate the construction of gas separation devices having a large gas separation surface area over a given apparatus volume. Hollow fibers are known to be able to withstand greater pressure differences than non-carrier film layers having substantially the same overall thickness and morphology.

When performing the multi-component membrane separation of the present invention, at least one gas from the gas mixture is separated from the at least one other gas by selective filtration to obtain a filtered product containing at least one separate gas. In this process, the gas mixture contacts one surface (i.e., the inlet surface) of the multicomponent membrane, and with respect to at least one gas pair in the gas mixture, the multicomponent membrane has a selective ability to filter one gas from the gas pair. The opposite surface (i.e. the exit surface) of the multicomponent membrane is maintained at a lower chemical potential for at least one of the filtered gases than the chemical potential on said first surface. In this process, at least one of the filtered gases is passed through a multicomponent membrane and removed from the proximal opposite surface to a filtered product having a different fraction of said at least one gas mixture to said at least one other gas mixture than the fraction of said at least one gas said at least one other gas in the original mixture. In the multicomponent membrane separation of the present invention, at least one gas is concentrated at the inlet side of the multicomponent membrane to obtain a concentrated product, and the at least one gas is filtered through the multicomponent membrane to obtain a filtered product in which said different gas ratio has a higher value.

The multi-component membrane according to the invention is characterized in that the porous coating separation membrane which is in occlusive contact with each other has a considerable void volume. The multicomponent membrane according to the invention is particularly suitable for selectively separating hydrogen from a gas mixture which contains, in addition to hydrogen, at least one of the following gases: carbon monoxide, carbon dioxide, helium, nitrogen, oxygen, argon, hydrogen sulphide, nitrous oxide, ammonia and hydrocarbons. up to 5 carbon atoms. The multicomponent membrane according to the invention is used in gas separation plants, the apparatus comprising at least one multicomponent membrane according to the invention. Said multicomponent membrane according to the invention has an inlet surface and an opposite outlet surface, the apparatus further comprising a unit for supplying process gas to the apparatus and for discharging gases from near the inlet surface of the multicomponent membrane and the filtered product near the outlet surface of the multicomponent membrane.

It has surprisingly been found that a coating material having a low determined internal separation factor may be used as a coating material, the coating being formed on a porous separation membrane, which may also have a low separation factor, thereby obtaining a multi-component membrane, which has a separation factor greater than that of both the coating and the porous separation membrane. This result is totally unexpected and contrasts with previous designs of prior art composite gas separation membranes having superimposed membranes supported on a porous carrier that essentially require the superimposed membranes to exhibit a high separation factor in order to achieve the desired selectivity for separation. membrane. It has been found that coatings having low separation factors can be used in conjunction with porous separation membranes to form multi-component membranes having a larger separation factor than both the coating and the porous separation membrane, resulting in highly preferred multi-component gas separation membranes. For example, materials having suitable separation factors but which have hitherto been difficult to use as superimposed membranes can be used as the porous separation membrane material of the present invention, wherein the porous separation membrane material with a given selectivity contributes significantly to the higher separation factor of the multi-component membrane.

Accordingly, the porous separation membrane of a multi-component membrane may be anisotropic with a thin but relatively dense separation region. The porous separation membranes then have the advantage of having a low resistance to filtration, which has hitherto known anisotropic membranes, and moreover the multicomponent membranes thus prepared exhibit the desired separation factors. In addition, the presence of flow channels that render the one-component (unfolded) anisotropic gas separation membranes unusable may be acceptable and even suitable as porous separation membranes in the multi-component membrane of the present invention. Preferably, the coating has a low filtration resistance and the coating material preferably has a low determined internal separation factor. In some multi-component membranes, the coating may have a tendency toward selective resistance in terms of permeation of the desired gas, yet the resulting multi-component membrane containing the coating may exhibit a separation factor greater than that of a porous separation membrane.

The multicomponent membrane according to the invention represents a combination of a pre-made porous separation membrane, i.e. a porous s-eparation membrane, which is produced before the coating is applied and the coating. In particular, the invention is directed to multi-component separation membrane membranes, wherein the selectivity of the separation nanoparticles; the porous separation membranes significantly contribute to the selectivity and relative filtration rate of the filtered gas through the multi-component membrane. Multicomponent membranes of the present invention may generally exhibit higher filtration rates than prior art composite membranes using superimposed membranes with high separation factors. Furthermore, the multi-component membranes of the present invention exhibit a separation factor that is superior to the coating and porous separation membranes. The multicomponent membranes of the invention may in some respects be analogous, but only seemingly, to prior art gas separation membranes having superimposed membranes having a high separation factor on a porous support. These prior art composite membranes do not use a carrier or substrate that contributes substantially to the separation process.

The multi-component membranes of the invention allow for great adaptability to specific types of separation, since both the coating and the porous separation membrane contribute to the overall separation performance. The result is an increased ability and ability of these membranes to adapt them to specific separation requirements, for example, separation of desired gas or gases from different gas mixtures to achieve desirable combinations of separation speed and selectivity that can be applied in industrial practice. The multi-component membranes of the present invention can be made of a variety of materials used for gas separation, which means greater possibilities for selecting suitable membrane materials for gas separation than hitherto. Moreover, these multi-component membranes are capable of providing good physical properties such as stiffness, abrasion resistance, strength, durability and good chemical resistance.

The invention is particularly directed to multi-component gas separation membranes comprising a coating in contact with a porous separation membrane, wherein the separation properties of the multi-component membrane are in principle determined by the porous separation membrane, as opposed to the prior art where the coating is a critical part .

The multi-component membranes of the present invention are widely applicable to gas separation. The gas mixtures suitable for separation by the multi-component membranes of the invention are gaseous substances or substances which are normally liquid or solid, but are in a gaseous state at the temperature at which the separation takes place. The invention, as disclosed herein, relates mainly to the separation of, for example, oxygen from nitrogen, hydrogen from at least one of the following gases selected from the group consisting of carbon monoxide, carbon dioxide, helium, nitrogen, oxygen, argon, hydrogen sulfide, nitrous oxide, ammonia and hydrocarbons having from 1 to 5 carbon atoms, in particular methane, ethane and ethylene; further ammonia from at least one of hydrogen, nitrogen, argon and C 1 -C 5 hydrocarbons such as methane; carbon dioxide from carbon monoxide or C 1 -C 5 hydrocarbons, such as methane; helium from a C 1 -C 5 hydrocarbon such as methane; hydrogen sulfide of a C 1 -C 5 hydrocarbon such as methane, ethane or ethylene; and carbon monoxide from at least one of the group consisting of hydrogen, helium, male, and hydrocarbons containing 1 to 5 carbon atoms. It is to be understood, however, that the invention is not limited to these specific examples of separation of said gases, nor to the multicomponent membranes mentioned in the examples.

The multicomponent gas separation membranes of the present invention are in the form of a film or hollow fiber or fiber, the multicomponent membranes having a porous separation membrane or substrate and a coating in occlusive contact with the porous separation membrane. Some factors that affect the behavior of multicomponent membranes are the permeability constant of the coating and the porous separation membrane, the total cross-sectional area of the holes (ie pairs or flow channels) to the total surface area of the porous separation membrane, the relative thickness and porous separation membranes of the multi-component membrane. separation membrane and the most important factor is the relative resistance to the flow of filtered gas, both of the coating and of the porous separation membrane in the multi-component membrane.

Generally, the degree of multicomponent membrane separation is generally influenced by the relative resistance to gas flow for each gas of the gas mixture as the coating also has a porous separation membrane, which are selected according to their gas resistance.

The material suitable for making the porous separation membrane may be a solid natural or synthetic material having gas separation properties. In the case of polymers, the materials that form the porous separation membranes include both addition and condensation polymers, which may be cast, extruded or otherwise processed. The porous separation membranes can be made in a porous form, for example by casting from a solution that contains a solvent of the polymeric material, into a solvent that dissolves the other material little or not at all. The conditions used in spinning and / or casting and / or subsequent processing after this manufacture can affect the porosity and resistance to gas flow through the porous separation membrane.

Organic polymers mixed with inorganic filter materials are generally used to produce porous separation membranes. Typical polymers suitable for the porous separation membranes of the invention are substituted or unsubstituted polymers and are selected from the group consisting of polysulfones, polystyrenes, including styrene-containing copolymers, for example acrylonitrile styrene copolymers, styrene-butadiene copolymers and styrene-vinyl benzyl halide copolymers; polycarbonates, cellulose polymers such as cellulose acetate butyrate, cellulose propionate, ethyl cellulose, methyl cellulose, nitrocellulose, etc .; polyethers, polyarylene oxides such as polyphenylene oxide and polyxylylene oxide; polyesteramide diisocyanates; further polyurethanes, polyesters such as polyethylene terephthalate, polyalkyl methacrylate, polyalkylacrylates, polyphenylene terephthalate, etc .; polysulfides, polymers of monomers having an alpha-olefinic unsaturation other than those mentioned above, such as polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, vinyl poles such as polyvinyl chloride, polyvinyl fluoride, polyvinylidene chloride polyvinylidene fluoride, polyvinyl alcohol, polyvinyl esters such as vinyl polyacetate and polyvinylpropionate, polyvinylpyridines, polyvinylpyrrolidones, polyvinyl ethers, polyvinyl ketones, polyvinyl aldehydes, polyvinylvinylamines, polyvinylvinylamines, polyvinylbutyraldehydes, polyvinylvinylamines, polyvinylvinylamides, polyvinylvinylamides, polyvinylvinylamines, polyvinylvinylamines; polyallyls, polybenzobenzimidazole, polyhydrazides, polyoxadiazoles, polytriazoles, polybenzimidazole, polycarbodiimides, polyphosphazines, etc., and copolymers, including block copolymers, containing the repeating units mentioned above, such as acrylonitrile-vinylmethyl-sulfomethylsulfonyl ether-phenylsulfonyl ether terpolymers; and graft and mixed copolymers comprising any of the foregoing materials. Typical substituents of substituted polymers are halogens such as fluorine, chlorine, bromine, hydroxyl groups, lower alkyl groups, lower alkoxy groups, monocyclic aryl groups, lower acyl groups, and the like.

The selection of porous separation membranes for multi-component membranes according to the present invention for gas separation can be made on the basis of heat resistance, solvent resistance, mechanical strength of the porous separation membrane, as well as according to other factors given by the selective filtration working conditions. wherein the coating and the porous separation membranes have the desired relative separation patterns of the present invention for at least one gas pair.

The porous separation membrane is preferably at least partially self-supporting, and in some cases may be substantially self-supporting. The porous separation membrane may provide substantially all of the structural load-bearing capacity of the membrane, or the multi-component membrane may comprise as a component a structural carrier having little, if any, gas passing through.

The porous separation membrane, as already mentioned, consists of polysulfone. Polysulfones that can be used include those having a polymer backbone consisting of repeating structural units

where

R and R 'may be the same or different substituents and represent aliphatic or aromatic hydrocarbon radicals having 1 to 40 carbon atoms, the sulfur in the sulfone group being bound to the aliphatic or aromatic carbon atoms, and the polysulfone having an average molecular weight suitable for film or fiber formation typically, at least about 10,000. If the polysulfone is not crosslinked, its molecular weight is typically less than about 500,000, usually less than about 100,000. The repeating units are linked to each other, that is, the substituents R and R 'are linked to each other by a bond carbon-carbon or various other linking groups such as

-0-,

О

II —c-Ν—,

AND

Η о

II —Ν — С — Ν—, I I Η Η ο

li —О — C— etc.

Particularly preferred polysulfones are those in which at least one of the substituents R and R‘ is an aromatic hydrocarbon radical and the sulfonyl radical is bonded to at least one aromatic carbon atom. Typically, aromatic hydrocarbon radicals include phenylene and substituted phenylene radicals, biphenyl and substituted biphenyl radicals, biphenylmethane and substituted biphenylmethane radicals having the general formula

substituted and unsubstituted biphenylethers of formula (7)

R R '

V. (~ ^ O) —x {'A P

where

X represents an oxygen or sulfur atom, and the like. In said biphenylmethane and biphenylether radicals, R 1 to R 10 are substituents which may be the same or different and which have the structure where:

X 1 and X are either the same or different and are hydrogen or halogen (e.g., fluorine, chlorine, and bromine), p is zero or an integer positive, e.g., from about 1 to 6, and

Z represents a hydrogen atom, a halogen atom (e.g. fluorine, chlorine and bromine),

R 11 (where q is zero or 1, Y represents

-0-,

-S-ss -0C-,

II o

or

and R 11 represents a hydrogen atom, a substituted or unsubstituted alkyl group containing, for example, from 1 to about 8 carbon atoms, or a substituted or unsubstituted aryl group (for example, a monocyclic or bicyclic group containing from about 6 to 15 carbon atoms); at least one of nitrogen, oxygen and sulfur, monocyclic or bicyclic having about 5 to 15 ring atoms, a sulfate and sulfone group, especially a lower alkyl group or a monocyclic or bicyclic aryl group; a phosphorus atom, such as a phosphine, phosphate and phosphone group, especially a phosphate and phosphone group, containing a lower alkyl or monocyclic or bicyclic aryl group, an amino group, namely a primary, secondary, tertiary and quaternary amine group, usually containing lower alkyl or a monocyclic or bicyclic aryl radical, an isothiourea group, a thiourea group, a guanidyl group, a trialkylsilyl group, a trialkyltin group, a trialkyl lead group, a dialkylantimmonium group, etc. -4z | Έ ^X 2 z, i.e., R ⁷ to R ¹⁰ are hydrogen atoms. Polysulfones having an aromatic hydrocarbon residue typically have good thermal stability, are resistant to chemical attack, and have an excellent combination of stiffness and flexibility. Useful polysulfones are sold under various trade names and have linear chains of formula r

wherein n, which represents the degree of polymerization, is from about 5 ° to about 80.

Polyarylene ether sulfones are preferred. Also useful are polyethersulfones having a structure

By modifying the polymer, for example, by cross-linking, grafting, quaternizing, and the like, it is possible to produce other useful polysulfones.

In the production of porous membranes in the form of hollow fibers, spinning can be carried out under various conditions. One method for producing polysulfone hollow fibers is described by Cabass et al., Research and Development of NS-1 and Related Polysulfone Hollow Fibers for Reverse Osmosis Desalination of Seawater, supra. Particularly preferred hollow fibers from polysulfones and polyethersulfones can be made by spinning the polysulfones in a solution containing the polysulfone solvent. Typical solvents are dimethylformamide, dimethylacetamide and N-methylpyrrolidone. The weight content of the polymer in the solution may vary considerably, but must be sufficient to produce the hollow fibers under spinning conditions. The polymer content of the solution, expressed as a percentage by weight, is usually from about 15 to 50 percent, for example from about 20 to 35 percent. If the polysulfone and / or solvent contains contaminants such as water, particles, etc., the amount of such contaminants should be low enough to spin. If necessary, contaminants in the polysulfone and / or solvent can be removed. The size of the spinneret may vary depending on the desired inner and outer diameter of the hollow fiber produced. For example, one of the types of spinnerets may have nozzle diameters of 0.38 to about 0.88 millimeters and a nozzle tip diameter of about 0.2 to 0.38 millimeters with an injection capillary inside the tip. The diameter of the injection capillary may vary within the ranges given for the tip diameter. The spinning solution is typically maintained under a substantially inert atmosphere to prevent contamination and / or coagulation of the polysulfone prior to spinning and to avoid the risk of ignition of volatile and flammable solvents. Dry nitrogen is a suitable atmosphere. The presence of excess gas in the spinning solution can result in large holes.

The spinning may be carried out using a wet nozzle technique or a dry nozzle technique, i.e. the nozzle may be in a coagulation bath or may be outside the bath. The wet nozzle technique is usually used for its convenience. Preferably, the spinning conditions are such as to prevent inappropriate fiber tension. The spinning speed is usually in the range of 5 to 100 liters per minute, although a higher spinning speed can be used, provided that the fiber is not undesirably tensioned and that a sufficiently long residence time in the coagulation bath is ensured. In principle, any liquid that is not a polysulfone solvent can be used for the coagulation bath. Preferably, water is used as the main component in the coagulation bath. The fluid is usually injected inside the fiber. The fluid may be, for example, air, isopropyl alcohol, water or the like. The length of time the fiber is drawn off in the coagulation bath is at least sufficient to ensure the fiber solidifies. The temperature of the coagulation bath can be varied within a wide range, for example from -15 ° C to 90 ° C or more, most typically about 1 ° to 35 ° C, usually about 2 ° to 8 ° or · 10 ° C. It is further desirable that the coagulated hollow fiber be washed with water to remove the solvent. In this treatment, the fiber is immersed in a water bath for about two hours. Typically, the fibers are dried prior to application of the coating and use in a gas separation apparatus. The drying may be carried out at a temperature of about 0 to about 90 ° C, preferably at about room temperature, for example about 15 to 35 ° C, and at about 5% to about 95% relative humidity, preferably at about 40% to about 60% moisture.

The foregoing description of a method for producing porous hollow fiber separating membranes from polysulfone has been presented for illustrative purposes and to illustrate an exemplary method applicable to the production of the porous separation membranes of the present invention, without being limited thereto.

The coating may be in the form of a substantially continuous continuous membrane, i.e. a substantially non-porous membrane, the coating being in contact with the porous separation membrane, or the coating may be discontinuous or intermittent. If the coating is intermittent, it is sometimes referred to as occlusion material, because it can occlude the gas flow passages, i.e. the occlusion material. pores. The coating is preferably not thick enough to adversely affect the performance of the multicomponent membrane, for example by causing an undesired reduction in gas flow, or by causing resistance to the gas flow to such an extent that the separation factor of the multicomponent membrane is substantially the same as the separation factor. coating. The coating typically has an average thickness of up to about 50 nanometers. If the coating is intermittent, there may be areas in which there is no coating material. The coating can often have an average thickness ranging from about 0.0001 to 50 nanometers. In some cases, the average coating thickness is less than 1 nm and may even be less than about 0.5 nm. The coating may consist of one layer or at least two separate layers, which may or may not be of the same material. If the porous separation membrane is anisotropic, i. Since it has a relatively dense region in its structure that is a barrier to gas flow, it is desirable to apply the coating so that it is in occlusive contact with the relatively dense region. The relatively dense region may be on any surface of the porous separation membrane or may be in the center of the porous separation membrane layer. The coating is preferably applied to at least one of the surfaces, i. on the inlet or outlet surface of the porous separation membrane. If the multi-component membrane is in the form of a hollow fiber, then the coating may be applied to the outer surface, thereby protecting and / or storing the handling of the multi-component membrane.

Although any suitable method may be used to apply a coating to a porous separation membrane, it should be noted that this method has a major effect on the overall performance of the multi-component membrane. For example, the multicomponent membranes of the invention may be manufactured by coating a porous separation membrane with a material comprising a coating material such that the multicomponent membrane coating has a low resistance to gas flow compared to the total multicomponent membrane resistance.

The coating may be applied in any suitable manner, for example, the coating operation is spraying, glazing, immersion in a substantially liquid substance containing the coating material, and the like. As mentioned previously, the coating material is preferably contained in a substantially liquid substance upon application and may be in the form of a solution using a coating material solvent that does not substantially dissolve the porous separation membrane. In a preferred embodiment, the coating material is preferably applied to one surface of the porous separation membrane and a lower absolute pressure is applied to the other surface of the porous separation membrane. If the substantially liquid substance comprises a peroxymageable material and the polymerizable material is polymerized on the porous separation membrane after application to form a coating after application, then the second surface of the defeating separation membrane is preferably subjected to a lower absolute pressure during or prior to polymerization. However, the invention as such is not limited to a specific method by which a coating material is applied to a porous separation membrane. Particularly preferred coating materials have relatively high permeability constants for gases, so that the presence of the coating does not greatly reduce the filtration rate of the multi-component membrane. The resistance of the coating to the gas flow is preferably relatively small compared to the resistance of the multi-component membrane. As mentioned above, when preparing a multi-component membrane with a desired release factor according to the invention, the choice of coating materials depends on the relationship of the determined internal separation factor of the coating material to the determined internal separation factor of the porous separation membrane material. The coating material should be able to provide occlusive contact with the porous separation membrane. For example, when applied, the coating should be sufficiently wettable and adhesive to the porous separation membrane to allow occlusive contact to be formed. The wetting properties of the coating material can be determined by combining the coating material, either alone or in a solvent, with the porous separation membrane material. In addition, the coating material may be selected according to a suitable molecular weight, taking into account the average pore diameter of the porous separation membrane. If the molecular size of the coating material is too large for the coating material to enter the pores of the porous separation membrane, the coating material is not usable for occlusive contact.

If, on the other hand, the size of the molecules of the coating material is too small, it may pass through the pores of the porous separation membrane during the coating and / or during the separating operation. For a porous separation membrane with larger pores as opposed to a porous separation membrane with smaller pores, it is then appropriate to use a coating material having a larger molecular size. If the pores are very diverse in size, it is appropriate to use as a coating material a polymerizable material that is polymerized after application to a porous separation membrane, or? it is desirable to use two or more coating materials of different molecular sizes, for example, to apply coating materials in order of increasing molecular sizes.

The coating material may be a natural or synthetic material, usually polymers, which preferably have adequate properties to make occlusive contact with the porous separation membrane. Synthetic materials include both addition and condensation polymers. Typical examples of materials that can be used as coating materials are polymers, which may be substituted or unsubstituted, solid or liquid under gas separation conditions, namely synthetic rubbers, natural rubbers, relatively high molecular weight and / or high boiling liquids, organic prepolymers, polysiloxanes (silicone polymers), polysilazans, polyurethanes, polyapichlorohydrin, polyamines, polyimines, polyamides, copolymers containing acrylonitrile, such as polyesters (α-chloroacrylonitrile) copolymers, polyesters [including polylactams], for example polyalkylacrylates and polyalkyl methacrylates, where the alkyl alkyl group contains 1, up to 8 carbon atoms, polysebacates, polysuccinates and alkyl resins, terpenoid resins such as linseed oil, cellulose polymers, polysulfones, especially aliphatic polysulfones, polyallkylene glycols such as polyethylene glycol, polypropylene glycol polyalkylenepolysulphates, polypyrrolidones, monomer polymers having α-olefinic unsaturation, such as polyolefins, for example polyethylene, polypropylene, polybutadiene, poly-2,3-dichlorobutadiene, polyisoprene, polystyrene including polystyrene copolymers, for example styrene-butadiene polyvinyls such as polyvinyl alcobols, polyvinyl aldehydes (such as polyvinylformaldehyde and polyvinylbutyraldehyde], polyvinyl ketones (e.g. polymethylvinyl ketone), polyvinyl esters (e.g. polyvinylbenzoate), polyvinyl halides (e.g. polyvinylbromide, polyvinylbenzene halide), polyvinylidene halide, polyvinylbenzene halide, polyvinylidenide, polyvinylbenzene; -1,5-cyclooctadiene, polymethylisopropenyl ketone, fluorinated ethylene copolymer; polyarylene oxides such as polyxylylene oxide; polycarbonates, polyphosphates such as polyethylene methylene phosphate and the like; and any copolymers including block copolymers containing the repeating units of the above, and graft copolymers and mixtures containing any of the foregoing. When applied to a porous separation membrane, these polymers may or may not be polymerized.

Particularly suitable coating materials are polysiloxanes. Typical polysiloxanes may contain aliphatic or aromatic residues and usually have repeating units of 1 to about 20 carbon atoms. The molecular weight of the polysiloxanes may vary widely, but is usually at least 1000. Polysiloxanes that are applied to a porous separation membrane typically have a molecular weight of from about 1,000 to 300,000. Typically, the aliphatic and aromatic polysiloxanes are polymonosubstituted siloxanes, for example those where substituents are lower aliphatic groups, for example lower alkyl, including cycloalkyl groups, especially methyl, ethyl and propyl; further lower alkoxy groups, aryl groups which include mono- and bicyclic aryl groups including biphenylene, naphthalene, etc .; further lower mono and bicyclic aryloxy groups; furthermore acyl groups comprising lower aliphatic and lower aromatic acyl groups, and the like. Aliphatic and aromatic substituents may be substituted, for example, halogens such as fluorine, chlorine and bromine, by hydroxyl groups, lower alkyl groups, lower alkoxy groups, lower acyl groups, and the like. The polysiloxanes can be crosslinked by the action of crosslinking agents to form a silicone rubber. The polysiloxanes may thus be copolymers with a cross-linking comonomer, such as α-methylstyrene, which co-forms a cross-linked product. Typical catalysts that promote crosslinking include organic and inorganic peroxides. Crosslinking may be performed prior to application of the polysiloxanes on the porous separation membrane, but is preferably performed after application to the porous separation membrane. Typically, the polysiloxanes have a molecular weight of from about 1,000 to about 100,000 prior to cross-linking. Some polysiloxanes do not wet the polysulfone porous separation membrane enough to cause occlusive contact in the desired form. However, dissolving or dispersing polysiloxanes in a solvent that does not substantially affect the polysulfone may facilitate occlusive contact. Suitable solvents include conventional liquid solvents

2Э alkanes such as pentane, cyclohexane, etc., aliphatic alcohols such as mothanol, some halogenated alkanes, dialkyl ethers and the like, and mixtures thereof.

The following materials used to prepare porous separation membranes and coatings are representative useful materials whose combination can yield the multi-component membranes of the present invention that can be used for gas separation. These materials, whose combinations and applications are merely representative of a wide variety of materials useful in the present invention and therefore do not limit the scope of the invention, are merely illustrative of the applicability and suitability of these materials. Typical porous separation membrane materials for separating oxygen from nitrogen include acetate celluloses, for example acetate cellulose having a degree of substitution of about 2.5, polysulfone, a styrene-acrylonitrile copolymer, for example, having about 20 to 70 weight percent styrene and about 30 to 30 weight percent. 80 weight percent acrylonitrile, blends of styrene acrylonitrile copolymers and the like. Suitable coating materials include polysiloxanes (polysilicones), for example polydimethylsiloxane, poilyphenylmethylsloloxane, polytrifluoropropylmethylsiloxane, pre-cured and post-cured silicone rubber, etc., polystyrene, for example polystyrene with a degree of polymerization of from about 2 to 20, further polyopren, cis-1,4-isoprene, further containing aliphatic hydrocarbon containing from about 14 to 30 carbon atoms, for example hexadecane, linseed oil, especially crude linseed oil, etc.

Typical porous separation membrane materials for separating hydrogen from a hydrogen-containing gas mixture include acetate celluloses, such as acetate cellulose having a degree of substitution of about 2.5, polysulfone, a styrene acrylonitrile copolymer, such as having a styrene content ranging from about 20 to 70 percent by weight. an acrylonitrile in the range of about 30 to 80 percent by weight, styrene acrylonitrile copolymer blends, etc., polycarbonates, polyacrylene oxides such as polyphenylene oxide, polyxylene oxide, brominated polyxylylene oxide, brominated polyxylylene oxide post-treated with trimethylamine, thiourea, etc. include polysiloxanes (polysilicones), for example polydimethylsiloxane, pre-cured and post-cured silicone rubber, etc., polyisoprene, α-methylstyrene-dimethylsiloxane block copolymer, aliphatic carbon containing compounds a radical of about 14 to 30 carbon atoms, and the like.

The porous release membranes of the present invention are preferably sufficiently porous and therefore have a sufficient area of porous release material to effect industrial scale division. The porous separation membranes have a significant effect on the separation process carried out using the multi-component membranes of the present invention and it is therefore desirable to achieve a large ratio of total surface area to total pore cross-sectional area of the porous separation membrane. This result differs completely from the prior art in the field of composite membrane production, where the separation takes place essentially on a superimposed membrane and where the carriers are said to be as porous as possible while maintaining their original and main function, i.e., in the process. the function of the carrier of the superimposed membrane, and wherein preferably the carrier does not affect the flow of filtered gas, that is, it does not inhibit the gas flow of the superimposed membrane.

The amount of gas passing through the porous separation membrane material and its effect on the performance of the multicomponent membranes of the present invention is greatly influenced by the ratio of the total surface area to the total pore area and / or the average pore diameter of the porous separation membrane. The ratio of total surface area to surface area of total pore cross-sectional area is typically at least about 10 for porous separation membranes; 1, preferably at least 10 ³ : 1 to 10 ⁸ : 1, wherein some porous separation membranes may have this ratio of 10 ³ : 1 to 10 ®: 1 or 10 ¹² : 1. The average pore diameter of the cross-section may be within wide limits, typically in the range of about 0.5 to 2000 nm, and in some porous separation membranes, particularly some polysulfone porous separation membranes, the average pore diameter of the a cross-section of about 0.5 to 100 or even 500 nm, usually in the range of about 0.5 to 20 nm.

It is an essential feature of the present invention that the coating is in occlusive contact with the porous separation membrane, wherein samples developed by observing the function of the multi-component membranes of the present invention and in which a non-coated porous separation membrane is used. the flow resistance through the pores increased, and the ratio of the pores through the porous separation membrane material to the pores through the pores was higher.

For gas separation membranes, an effective separation thickness is a useful characteristic. Effective separation thickness in the description of the present invention means the thickness of a continuous (non-porous) and compact membrane formed of a porous separation membrane material having the same gas filtration rate as a multi-component membrane, i.e. the effective separation thickness is the permeability quotient of the porous separation material gas membranes divided by the permeability of the multi-component membrane for the gas. By obtaining a lower effective separation thickness, the gas flow rate of the gas is increased. The effective separation thickness of the multicomponent membranes is often substantially lower than the total thickness of the membrane, especially if the multicomponent membranes are anisotropic. The effective separation thickness of the multi-component membranes refers to the gas, which gas may be, for example, at least one of carbon monoxide, carbon dioxide, nitrogen, argon, sulfur hexafluoride, methane and ethane. This effective separation thickness is usually less than about 10,000 nm, preferably less than about 1,500 nm, i. in the range of about 10 to 1500 nm. In multi-component membranes containing, for example, polysulfone porous separation membranes, the effective separation thickness of the multi-component membrane for at least one of said gases is less than about 500 nm. The effective separation thickness of some multicomponent membranes, particularly with respect to at least one of the above-mentioned gas, is less than about 50 nm, preferably less than about 20% of the thickness of the multicomponent membrane.

According to the prior art, in one method of manufacturing gas separation membranes for pores containing pores, at least one of the pores of the porous membrane is treated, thereby compacting the surface and thereby reducing the occurrence of pores, which themselves reduce the selectivity of the separation membrane. The compaction is effected, for example, by chemical treatment with solvents or agents to swell the membrane material or by annealing, which can be carried out with or without contacting the membrane material with the liquid. Such compaction processes usually result in a significant reduction in the gas flow through the membrane. Some particularly preferred multicomponent membranes of the present invention exhibit greater permeability than a membrane substantially the same as the porous separation membrane used in the multicomponent membrane of the invention, except that at least one of the membrane surfaces has been treated to sufficiently compact the membrane to sufficiently anneal in the presence or absence of a liquid, thereby obtaining, with respect to at least one gas pair, a separation factor equal to or greater than the separation factor of the multi-component membrane. Another method to increase the selectivity of membrane separation is to adjust the manufacturing conditions, thereby obtaining a membrane less porous than a membrane produced under unchanged manufacturing conditions. An increase in the selectivity of the partition due to the modification of the manufacturing conditions is usually associated with a substantially lower gas flow through the membrane. Some particularly preferred multicomponent membranes of the present invention, e.g., membranes in which the porous hollow fiber membrane is more permeable than an anisotropic hollow fiber membrane formed from the porous separation membrane material, are capable of maintaining the hollow fiber configuration under the conditions of gas separation, for example at an absolute pressure difference of 1 MPa, and the hollow fiber anisotropic membrane has a separation factor equal to or greater than the separation factor of the multi-component membrane with respect to at least one gas pair.

Preferably, the porous separation membrane is sufficiently thick that no special apparatus is needed to handle it. The porous separation membrane typically has a thickness of about 20 to 500 nm; about 50 to 200 or 300 nm. If the multicomponent membrane is in the form of a hollow fiber, the fiber typically has an outer diameter of about 200 to 1000 microns, i.e. about 200 to 800 microns, and a wall thickness of about 50 to 200 or 300 microns.

In gas separation, including gas concentration processes using multicomponent membranes of the present invention, the exit side of the multicomponent membrane is maintained at a lower chemical potential for at least one filtered gas than the chemical potential of the inlet side. The driving force for the desired filtration process using the multicomponent membrane according to the invention is the difference in chemical potential of this multicomponent membrane, see for example Olaf A. Hougen а К. M. Watson: Chemical Process Principles, Volume II, John Wiley, New York (1947), resulting in differences in partial pressures The filtered gas enters, passes through, and is removed from near the exit side of the multicomponent membrane so that The operation of the multicomponent membrane according to the invention does not depend on the direction of gas flow or which surface of the membrane is the inlet surface, i.e., which comes into contact with the gas mixture to be treated.

In addition to the fact that the process of separating at least one gas from the gas mixture using the multi-component membrane of the present invention does not require costly cooling and / or other energy costly measures, this process provides numerous advantages in high degree of variability in performing selective filtration operations. The multicomponent gas separation membranes of the present invention, whether in the form of foil or hollow fiber, are useful for separating industrial gases, concentrating oxygen for medical use, for pollution control devices, and for any other process requiring separation of at least one gas from the gas mixture. Relatively less often, single-component membranes have both a sufficiently high degree of selectivity of separation and good filtration rate characteristics, and even then, these single-component membranes are suitable for separating only a few specific gases. In contrast, the multi-component gas separation membranes of the present invention can utilize a variety of materials to form a porous separation membrane, i. materials that were previously unsuitable for mono-component membranes due to the unacceptable combination of filtration rate and separation factor. Since the selection of materials for making the porous separation membrane can be made according to the invention according to its selectivity and permeability constant for the gases and not its ability to form thin and sufficiently non-porous membranes, the multicomponent membranes of the present invention can advantageously be adapted to separate various gases from gas mixtures.

In cross-section, the pores / pores of the separation membrane pore diameter can be of the order of tenths of a nanometer, and thus pores of the porous separation membrane and the surface between the coating and the porous separation membrane cannot be directly observed using currently available optical microscopes. Currently, technical means are available which allow greater sample magnification, such as scanning electron microscopy and transmission electron microscopy, but which require special sample preparation, which limits their usefulness in accurately imaging the contours of the samples, especially the organic sample. For example, scanning electron microscopy requires that the organic sample be coated with, for example, at least 4 to 5 nanometers a thick layer of gold to obtain reflection to obtain a readable image. Even the way the coating is applied can affect the scanned image. In addition, the mere presence of the coating required by scanning electron microscopy can furthermore obscure or obviously change the contours of the sample. Plus both in comparative. In electron microscopy and transmission electron microscopy, the methods used to obtain a sufficiently small sample can substantially change the contours of the sample. Thus, the complete structure of a multi-component membrane cannot be visually detected even with the best available microscope technique.

The multi-component membranes of the present invention have unique properties, which can be demonstrated by various methods and mathematical models whose results are consistent with the generally observed effects of the multi-component membranes of the present invention. However, these mathematical models do not limit the scope of the invention, but serve as further illustrations of the novel and advantageous properties of the multi-component membrane of the invention.

1, 2, 3, 4, 6 and 7, a multicomponent membrane according to the present invention is shown in order to illustrate the following mathematical model in more detail. FIG. 5 illustrates an analogy between the concept of flow resistances to the filtrate flow through the multi-component membrane of the invention in connection with the following mathematical model and the concept of flow resistances.

The illustrated models are only intended to facilitate understanding of the concepts associated with the following mathematical model, but are not illustrative of, nor intended to illustrate the true structure of the multi-component membranes of the invention. In order to explain the concept of the mathematical model in more detail, these models illustrate the features included in the mathematical model. To simplify the representation of these models, individual features and dimensional relationships are greatly overstated.

For the purpose of explaining the mathematical model below, Figures 1, 2 and 4 show models which illustrate the interface between the coating and the porous separation membrane, i. the magnified area indicated in FIG. 6 as the area between the lines A-A and R-B, but not necessarily on the same scale. Fig. 3 illustrates an enlarged model of the region designated in Fig. 7 as the region between lines C-C and D-D. In the illustrated models, similar designations of the parts or the same reference numerals refer to the same features.

Fig. 1 shows an enlarged cross-sectional view of a multi-component membrane comprising a substantially continuous continuous surface layer 1 of coating material X in contact with the material Y of the porous separation membrane and a solid part 2 comprising pores 3 filled or partially filled with material X.

FIG. 2 is an enlarged illustration of another type of multicomponent membrane where the material Y of the porous separation membrane forms a surface interface in the form of a curved surface, the surfaces being separated by gaps or partially filled by the coating material X and making a uniform contact.

FIG. 3 illustrates on a larger scale another multi-component membrane in which the material is within the pores 3 but does not form a continuous surface layer.

Fig. 4 illustrates another multicomponent membrane to facilitate understanding of the mathematical model described below. This Fig. 4, together with Fig. 5, represents the analogy of a well-known resistor electrical circuit.

Fig. 6 is a further cross-sectional view of the illustrated model, wherein the coating material X is provided with a pore blocking film cast on a dense surface of a porous separation membrane characterized in that it has progressively increasing density and porous structure throughout membrane layer.

Finally, FIG. 7 illustrates a cross-section of an occluded-anodotropic separation membrane model that does not necessarily require a continuous surface layer 1.

The following equations illustrate a mathematical model that was designed to elucidate the effects of the multi-component membranes of the invention. When using this mathematical model appropriately, separation membranes and coating materials can be selected to obtain the preferred multicomponent membranes of the invention.

As will be discussed below, the flow rate Qr, _{and the} gas through the multicomponent membrane can be reported as a function of resistance to the gas flow through each part (see, for example, the illustrated model in Fig. 4) of the multicomponent membrane analogously to the mathematical equivalent of the electrical flow of Fig. 5.

QT.a ⁼ ApT, and

fya ^R3 , a

- (1) where p _Ta is the differential pressure of gas at the multi-component membrane, and

R _Vn , R ₂ , and а Кз, а are the resistances to the gas flow through the surface layer 1, the resistance of the solid portions 2 of the porous separation membrane to the gas flow and the pore resistance 3 of the porous separation membrane to the gas flow.

The flow Q _{T h of the} second gas b through the same multicomponent membrane can be expressed in the same way, but with the appropriate gas pressure difference ba for the surface layer resistance 1 k of the gas flow b, the solid portions 2 of the porous separation membrane k the gas flow and pores 3 k of the gas flow b. Each of these resistors for gas b may differ from the resistors for gas a. In this way, selective filtration through a multi-component membrane can be achieved. Preferred multicomponent membranes can be modeled by varying the values of R1, R2 and R3 for each of the gases a and b to give the desired flow rates for each of the gases a and b, and varying the resistance to the gas flow and gas b.

Other equations that are useful to elucidate the mathematical model are given below.

The two gas separation factor a ^and _b ^a is defined for any separating material by equation (2) for the membrane ú of the material at a given thickness 1 and surface area A:

_a . Pfl.n Qa APb P ^h ~ _n b 'QbAPa (2) where

Pn a and Pn.b are permeability constants n for gases a and b, a

Q _a and Q _b are the gas flows a and b through the membrane, wherein

Ap _and а Арь represent the driving force of the process, that is, the partial pressure differences of the gases a and b through the membrane. _And gas flow rate Q membrane of a material gas and N can be expressed as _ APAP n and A _n _ .DELTA.Pa ^Ча ~ 1 ,. ~ Rn.a (3) where.

A "is the surface area of the membrane of material n, l _n is the thickness of the membrane of material n, and R", _and is the resistance of the membrane of material n to the gas flow a.

It can be seen from equation (3) that the resistance R, _1H can be expressed mathematically by equation (4):

(4)

This resistance is mathematically similar to the electrical resistance of the material to the current flow.

This mathematical model can be illustrated by the model shown, for example, in Fig. 4. A porous separation membrane can be conceived as comprising solid portions 2 of material Y and pores or holes 3. Material X is present in the illustrated model as surface layer 1 and as a material which is present in the pores 3 of the porous separation membrane. Each of these areas, i. the surface layer 1, the solid part 2 of the porous separation membrane and the pores 3 containing material X has a resistance to the gas flow so that the total multicomponent membrane can be compared to an analogous electrical circuit shown in FIG. Rt in series with two resistors Rz and R3 which are parallel to each other.

If the material X is formed in the form of a continuous compact surface layer 1, then the flow resistance Rt to the gas flow can be expressed by equation (4) and will be a function of the surface thickness It, the surface area Ai and the permeability constant P _x .

The porous separation membrane of the multi-component membrane of the present invention can be modeled as two resistors connected in parallel. According to equation (4), the resistance R2 of the solid portions 2 of the porous separation membrane containing material Y is a function of the thickness 12 of these solid portions; the total surface area Ag of the solids 2 and the permeability constant P _{Y of the} material Y. The pore resistance R3 of the porous separation membrane 3 is parallel to Rz. The pore resistance of R3 is given by equation (4), i.e. a thickness of 1з. divided by the permeability constant P i and the total surface area of the pore cross-section Аз. For the purposes of the mathematical model, it is assumed that 1з is given by the average penetration depth of material X into the pores 3, as shown in Figure 11a of the painted model in Fig. 4, and the permeability constant Рз is given by the permeability constant P _x of X.

The permeability constant P _x and P _Y are measurable properties of materials. The surface area A 1 can be determined based on the configuration and size of the multi-component membrane, the surface areas A 1 and A 2 can be determined using a conventional scanning electron microscope in combination with procedures based on gas flow measurement through the porous separation membrane. The thicknesses Ii, I2 and 1з can be determined in the same way. The Q _ru value for a multicomponent membrane can be calculated from equations (1) and (4) using the values A, I, I, I2, 13, P _x , Ai, Up, Аз, which can be determined experimentally. The separation factor _h ^u can be determined in a similar manner from equations (1) and (2).

The mathematical model facilitates the design of the preferred multicomponent membranes of the present invention. For example, since the separation of the at least one gas of the gaseous mixture from the at least one other gas is effected by means of preferred multi-component membranes substantially on the porous separation membrane, the porous separation membrane material may be according to its determined internal separation factor for said gases as well as its physical and chemical properties such as strength, stiffness, durability, chemical resistance, and others. The shape of the porous separation membrane can then be formed from the material using any suitable method. As noted above, the porous separation membrane may be characterized by scanning electron microscopy, preferably in combination with gas flow measurement, as exemplified by H. Yasudou et al., See Journal of Applied Science, Vol. 18, pp. 805-819 (1974).

The porous separation membrane can be modeled as two parallel resistances to the gas flow, namely the resistance of the solids 2 and the pore resistance 3. The pore resistance R3 depends on the average pore size, which determines whether the gas flow will be laminar flow or diffusion flow. Knudsen (see, for example, Hwang et al., Techniques of Chemistry, Vol. VII, Membranes in Separations, John Wiley & Sons, 1975, Chapter 12.) and pore numbers. Since the rate of diffusion of gases through open pores is much higher than the solid material, then the calculated resistance R3 to the pore gas flow is usually considerably less than the calculated resistance R? of the porous separation membrane, although the total pore cross-sectional area is much smaller than the total surface area of the solids. In order to increase the proportion of filtered gas through the solids 2 relative to the gas flow through the pores 3, the pore resistance R3 must be increased in proportion to the resistance R2 of the solids. This can be done in the model by placing X material in the pores, thereby reducing the diffusion velocity of the gases through the pores.

The multi-component membrane with the desired separation factor is obtained from the data relating to the desired increase in pore resistance to gas flow after obtaining an estimate of the pore resistance to gas flow and the resistance of the porous separation membrane to gas flow material. For convenience, it is preferable, but not unforgettable, to assume that the depth of the coating material in the pores (1з) and the distance (I2) of the minimum gas infiltration into the porous separation membrane material are the same. Then, based on the knowledge of the permeability constants of the coating materials, the coating material having the desired resistance can be selected. The coating material may also be selected according to other properties (in addition to increasing the R 3 value) as described below. If the coating material forms a surface layer on the porous separation membrane, as illustrated in Fig. 4, it may cause a flow reduction. The mathematical model of this situation is described in equation (1). In such a case, the properties of the coating material should be such that flow through the coating is not unduly reduced.

The choice of coating material depends on its determined internal separation factor relative to the determined internal separation factor of the porous separation membrane material and its ability to produce the desired resistance in the multi-component membrane. The coating material should be able to make occlusive contact with the porous separation membrane. The coating material of the appropriate molecular size may be selected according to the average pore size of the porous separation membrane. If the size of the coating material molecules is too large, or if the coating material connects the pores of the bridge surface, it follows from the model that the R3 resistance of the pores should not be increased relative to the R2 resistance of the solid portions of the porous separation membrane.

2S7751, in which case the ratio of the gases filtered through the solids 2 relative to the gases that have passed through the pores of diffusion should not increase against the ratio in the porous separation membrane itself. If, on the other hand, the size of the molecules of the coating material is too small, the coating may be drawn into the pores during the coating and / or during the separation operations.

The coating is usually carried out in the form of a surface layer 1 (see the illustrated model in FIG. 4) and, moreover, the coating material is also contained in the pores. In these cases, the surface layer 1 represents the resistance to the flow of gas Ri, which is in series with the combination of resistors of the porous separation membrane. If this situation occurs, the coating material should preferably be selected such that the surface layer of the multicomponent membrane does not impose excessive resistance to the gas flow (while having sufficient resistance in the pores) to effectively effect the separation of at least one of the porous separation membrane. Pair of gaseous gas mixtures. This could be achieved, for example, by using a coating material exhibiting high gas permeability constants and low selectivity.

Also, the thickness L1 of the surface layer, as shown in said model, can itself influence the flow and selectivity of the multicomponent membrane, since the resistance R1 of the surface layer 1 is a function of its thickness L1.

After selecting the appropriate materials X and Y, various forms of multi-component membranes can be modeled from these materials using equations (1), (2) and (4). From this mathematical model, for example, we can obtain information regarding the appropriate ratios of the total pore cross-sectional area з to the total surface area з 4-А of the porous separation membrane and the appropriate thickness of the separation layer 12 of the porous separation membrane. For example, this information may be useful in determining the production process of a porous separation membrane to have a desired surface area ratio of Α5 / Α2ΨΑ3, a desired separation thickness I2 as well as a desired thickness of the surface layer. In the case of porous hollow fiber anisotropic separation membranes, said parameters can be achieved by selecting spinning conditions and / or post-processing.

The above analysis illustrates the way in which different configurations of multicomponent membranes can be mathematically modeled. Also, some methods have been disclosed whereby relative resistance values of the surface layer 1, solid portions 2 and pores 3 of the porous separation membrane can be varied relative to at least one gas pair, thereby obtaining advantageous multi-component membranes having high flow rates as well as high selectivity for at least one gas pair.

In the following, a mathematical analysis will be performed which, by combining equations (3) and (4), yields the resulting equation (1).

From the well-known Ohm law for · electrical resistance, it is possible to obtain a mathematical expression for the total resistance R ^{T of the} electrical circuit, which is illustrated in Figure 5:

R ₁ = R _{1 +} R ₁₃ = R ₁₊ ^

15) where

R23 is a connected resistor R2 and R3 when both last resistors are connected in parallel, this value corresponds to the last term of equation (5).

Similarly, the mathematical model described above uses the same mathematical equations to express the total resistance to the gas flow through the multicomponent membrane, as illustrated on an enlarged scale in the model of Fig. 4. The resistance R23 represents the common resistance of both portions of the porous separation membrane. ie. If the coating does not form a substantially continuous surface layer 1, but this material X only enters the pores 3, then there is a situation as illustrated in Fig. 3 where the resistance of the surface layer Ri is then zero, and this term falls out of Equation (5) and all subsequent equations derived from Equation (5).

The total flow of a given gas through a multicomponent membrane is equal to the flow of electric current and at steady state is given by Equation (6):

Qr.u = Q1, a = Q23, _and (6) where

Q _{1 < a} is the gas flow through the surface layer 1, a

Q? 3, and θ combined flow through both solid portions 2 and pores 3 (filled with material X) of the porous separation membrane.

Q23, a ⁼ Q2, and Ь Оз, а (7)

The total partial pressure drop of gas in the multicomponent membrane is the sum of the partial pressure loss of the surface layer 1, the value Лр1, _а, and partial pressure losses solid portions 2 and the pores 3 filled with the porous separation membrane, the value of ₂ з Др, _а:

Apr.a = ,ρι, α + Д _{23 (} а (8)

The gas flow through each part of the multi-component membrane can be expressed by Equation (3), expressing the resistances and partial pressure losses of each part of the membrane as follows:

Italy (9)

Язз, а

Арзз.а (R,, and ^R 3.a L (10)

From equations (6), (8), (9) and (10), the expression p ₂₃ , _a , expressed in terms of resistances and total partial pressure loss, can be derived:

Лр23.а = ΑΡτ, η

Italy (11)

Equation (11) together with equation (6) and equation (10) provide equation (1).

According to the present invention, the coating is in occlusive contact with the porous separation membrane to obtain a multi-component membrane. The mathematical model described, which has been presented in order to explain some of the phenomena associated with the multi-component membranes of the invention, shows that the pores 3 of the porous separation membrane contain material X. The flow resistance of the five springs containing material X is much greater. than the resistance to the gas flow through pores that are not filled with material X, since the permeability of gases by any material is lower than the permeability of gases through open channels. Consequently, the Rs value in the multicomponent membrane is increased and, according to equation (10), R? then has a less significant effect on R? 3. Since Rs is opposite R? In the multi-component membrane, the proportion of part of the gas passing through the solid portions of the porous separation membrane to the part of the gas passing through the pores 3 filled with material X is higher than that in the porous separation membrane itself. Thus, the separation factor of at least one gas pair in the multi-component membrane is increased by interaction with the material Y compared to the separation factor in the porous separation membrane itself.

The following examples illustrate the multi-component membranes of the present invention without limiting the scope of the invention. All parts and percentages pertaining to gases are by volume and all percentages pertaining to liquids and solids are by weight unless otherwise indicated.

Examples 1 to 3

Examples 1 to 3 and Table 1 show multicomponent membranes consisting of a porous acetate cellulose separation membrane and a coating. Examples 2 and 3 show composite hollow fiber membranes for separating two different gas mixtures. In these two cases, it is seen that the membrane from the porous substrate divides to another stage the gas mixture even in the absence of coating, but in both cases the separation factor is much smaller than the determined internal separation factor of the acetate cellulose. In such porous separation membranes, most of the gas passes through the pores, with only a relatively small amount of filtrate passing through the cellulose acetate.

After coating of the separation membranes, the gas separation factor relating to the multi-component membranes of Examples 2 and 3 is greater than the determined internal separation factor of the coating material and the separation factor of the porous separation membrane. If we then compare the gas flow through the cellulose acetate with the pore gas flow in the multi-component membrane, then the gas flow through the cellulose acetate is greater. Thus, the separation factor of the multi-component membrane is much closer to the determined internal cellulose acetate separation factor.

Example 1 shows various hollow fiber samples of acetate cellulose with somewhat different properties of the coated and uncoated sample, which example can be compared to the results of Example 2. Although the porous separation membrane has a higher oxygen permeability and a lower separation factor, it has multi-component membrane higher separation factor compared to both the coating material and the porous separation membrane material when considered separately.

Table 1 “Permeability of multi-component membranes using porous acetate cellulose separation membranes ^b to separate oxygen from air and hydrogen from carbon monoxide / hydrogen

Example # 1 2 3 coating ^c polydimethyl- polydimethyl- polydimethyl- siloxane siloxane siloxane viscosity 0.1 Pa. with viscosity 0.1 Pa. with viscosity 0.1 Pa. with coating process ^d AND В C process gas air air CO / H2 concentrated gas (filtrate) O2 O2 H2 coating material, determined internal separation factor ^e , separation of O2 from N2 or Ha from CO 2.33 2.33 1.9 porous separation membrane, permeability ^a (O2 or H2 separation) 5,9.10 ⁶ 4.4.10 2.7. ⁵ porous separation membrane, separation factor ^e , (separation of O2 from N2 or H2 from CO) 2.2 1.6 9.2 multi-component membrane, separation factor ^e (separation of Osod N2 or H2 from CO) 4.09 5.03 22.0 multi-component membrane, permeability ^a (O2 or H2 separation) 2,2.10 ⁶ 1.6.10 ' ⁶ 1,5.10-5 cellulose acetate, determined internal separation factor ^e (separation of O2 from N2 or H2 from CO) 5.9 5.9 about 50

"Membrane permeability for a given gas is the volume of gas in cm ³ in normal conditions (pressure and temperature) which passes cm ² membrane surface area per second at a partial pressure difference of 13 mbar between the input and output side of the membrane per unit of thickness (unit cm ³ / cm ^{2 (} 1.3 kPa) ^b acetate cellulose (substitution degree about 2.5) spun by OSW Final Report No. 14—30-3030, Development of High Flux Hollox Osmosis For Brackish Water Softening, 1973. The fiber in Example 2 was post-treated with warm water ^C All coatings were liquid when applied and were not further vulcanized, polymerized or crosslinked after coating ^d Coating methods See Table 16 'The membrane separation factor for a gas pair is defined as membrane permeability for the first gas divided the permeability of the membrane to the second gas of the gas pair.

Examples 4 to 10

Examples 4 to 10 illustrate various liquid coatings for porous separation membranes of polysulfone in the form of a hollow fiber for selective separation of oxygen from air, which are shown in Table 2. These porous separation membranes do not separate oxygen from nitrogen. The coating membranes used are high molecular weight organic and silicone fluids that have a sufficiently low vapor pressure such that they do not evaporate readily from the coated surface and have separation factors for separating oxygen from nitrogen typically less than about 2.5. The size of the coating material molecules is small enough to achieve occlusive contact with the porous separation membrane, but is not unsuitably small enough to pass through the pores during coating and / or split coating material. The observed separation factors of these multi-component membranes are higher than that of the porous separation membrane (1.0 in all examples) and the coating material (2.5 or less for all of the coating materials shown in the examples).

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Examples 11 to 15

Examples 11-15 illustrate various coatings that are applied to the porous separation membrane either as liquids and immediately processed into solid polymer coatings (post-vulcanization) or as normal solid polymers dissolved in a solvent. The results are shown in Table 3. In these examples, oxygen is separated from the air by means of the multi-component membranes. In the above examples, variously processed porous polysulfone separation membranes are used in the form of a hollow fiber.

Table 3

Permeability of ⁸ multi-component membranes that use a polysulfone ^b porous separation membrane and polymerized coatings to separate oxygen from air

Example # 11 12 13 14 15 Dec coating additionally additionally poly (cis- additionally additionally vulkani- vulkani- -1,4-iso- vulkani- vulkani- zovaný zovaný pren) zovaný zovaný silicone silicone silicone siliko- rubber rubber rubber new rubber coating process ^c determined by internal separation E E D F F coating material factor permeability ^and porous sepa- 2.3 2.3 2,5-2,7 2.3 2.3 separation membranes (air) separation factor ^{d, e} porous 1,8.1ο- ⁴ 1,8. ΙΟ ⁴ 6.2. ⁴ ' ⁴ 2.1. ΙΟ ⁴ 1,2. ⁵ ' ⁵ separation membranes (division Chod N2) separation factor ^{d of} multicomponent membrane 1.0 1.0 1.0 1.0 about 1 (separation of O2 from N2) permeability ³ multicomponent 4.8 3.4 4.6 5.9 5.4 membranes (O2) 1,2. ΙΟ ³ 1.4. ⁵ ' ⁵ 5.8. ⁸ “ ⁸ 8,9.10-6 9,7.10-6 ^and see Table ^1b see Table 2

^c see table 1 note d ^d see table 1 note e ^e see table 2 note g

Examples 16 to 18

Examples 16 to 18 show that multi-component membranes that use a porous polysulfone separation membrane and which are in the form of a hollow fiber can also effectively separate hydrogen from the CO / H2 mixture. In Examples 16 and 18, the separation factor of the porous separation membrane was not measured prior to coating, but experiments with similar porous separation membranes indicate that the separation factors can be expected to have a value between about 1.3 and 2.5. This assumption is verified in Example 17, where the measured separation factor of the porous separation membrane for separating H2 from CO was 1.3. In some cases the separation of H2 from CO was 1.3. In some cases, the separation of H 2 from CO takes place by these porous separation membranes by Knudsen diffusion. These examples illustrate the possibilities of using various coatings, coating processes, permeability and separation factors of multi-component porous separation membranes. The same multi-component membranes were used in Examples 14 and 17 and in Examples 15 and 18. A comparison of these examples shows that. the use of a multi-component diaphragm in one or more gas mixtures does not prevent the diaphragm from being used later to separate another gas mixture. The results obtained are shown in Table 4.

Table 4 ’· '·

Permeability of multi-component membranes in which polysulfothic- ¹ porous separation membranes are used in the separation of hydrogen from CO / H2 mixtures

Example # 16 17 18 coating procedure ⁰ D F F determined internal separation factor of the coating material (H2 / CO separation) 3.5 1.9 1.9 permeability of ³ porous separation membranes (Hz) 9. * ⁵ separation factor ^{d, e} multicomponent membranes (H2 / CO separation) 15.4 30.2 31 permeability of ¹ multicomponent membrane (H2) 3,4.10 ⁵ 5,9.10-5 6,0.10- ⁵

^and see Table No. ^1b see Table No. 2 'see Table No. 1 note d see Table No. 1 note e “determined by an internal separation polysulf in the form of a continuous compact film for separating hydrogen from CO is about 40

Examples 19 to 21

Examples 19 to 11, the results of which are shown in Table 5, illustrate the filtration properties of multicomponent membranes of the invention assembled from various coating materials on a porous hollow fiber separating membrane of copolystyrene acrylonitrile in the form of a hollow fiber for air separation and CO / H2. In each example, the multi-component membrane had a higher separation factor than both the coating and the porous separation membrane itself. In Example 21, a porous separation membrane having a separation factor 15 for separating hydrogen from CO prior to post-train application is shown. the porous separation membrane has relatively few pores and the average pore diameter must be small. Comparison of Examples 20 and 21 shows that the multicomponent membrane in Example 20 has a higher filtration rate and a higher separation factor than the porous separation membrane of Example 21, although this membrane has a larger separation factor than the porous separation membrane of Example 20. From this It follows that the multicomponent membranes of the invention have a better filtration rate than a membrane having the same or greater separation factor, which consists essentially of a porous separation membrane material.

Table 5

Permeability of ³ multi-component membranes in which ¹ ”copolystyrenacrylonitrile separation membrane was used when separating hydrogen from CO / H2 and oxygen from air

Example # 19 Dec 20 May 21 coating additionally vulka- polydimethyl- polydimethylsiloxane nlzovaný slllko- siloxane, visco- viscosity 0.1Pa. with coating process ^b new rubber F zita 0.1 Pa. s В В feed gas air Ha / CO Ha / CO concentrated gas (filtrate) ^{02 /} Hz Hz determined internal separation factor ^{c of} coating material (U2 / № or H2 / CO division) 2.3 1.9 1.9 permeability of ³ porous separation membranes (air or H2I 6,5.10 ' ⁶ 6,5.10-5 5.6. ⁶ ' ⁶ separation factor of porous separation membrane (O2 / N2 or Ш / С0 division) 1.0 3.9 15 Dec separation factor 'of multicomponent membranes (O2 / N2 or H2 / CO separation) 3.8 25 45 permeability of ³ multicomponent membranes (O2 or H2 separation) 3.4.10 ' ⁶ 6,2.10-6 2,3.10-6 the determined internal separation factor ⁶ 'of the porous separation membrane material 7.0 80 80

^a see table 1 ^b see table 1 note d ^c see table 1 note e ^ the determined internal separation factor of the substrate is the separation factor of the continuous compact film of the material ^e copolymers consisting of 33% acrylonitrile and 67% styrene, in Examples 21 and 20 of higher molecular weight than Example 19; all were spun by hollow fiber-shaped duty from a spinning solution containing 27.5% solids in dimethylformamide to an aqueous coagulant at 0-10 ° C

Example 22

In this example, the multi-component membranes of Examples 15 and 18 were used to divide the gas stream, which consisted of five components. The gas stream to be treated contained hydrogen, carbon dioxide, carbon monoxide, nitrogen and methane with water and methanol up to saturation. The feed stream to be treated was fed at 40 psi at 40 ° C to the outer surface of the multicomponent membrane. The internal pressure was 0.1 MPa. In this example, the following values of permeability and separation factors for individual gases relative to hydrogen were found:

permeability ⁺ for: separation factor Hz from: H ₂ (8,5.10'5) CO ₂ (3.7.10 ' ⁵ ) CO2 2.3 CO (0.27.10'5) WHAT 31.0 N2 (0.68.10'5) Nz 12.4 СШ (0.23 ΙΟ ' ⁵ ) CH < 36.9

⁺ in cm ³ / cm ² units. p. 1.3 kPa at standard temperature and pressure

From the above results, it can be seen that hydrogen can be readily separated from a gas mixture containing at least one of the CO, N 2 - and CH 4 gases. The presence of one or more other gases in the mixture, such as water and methane vapor, does not prevent separation on the multi-component membrane of the present invention. It is also apparent from the above that other gases can be separated from the mixture, for example, the separation factor for separating carbon dioxide from carbon monoxide would be a permeability ratio of about 14. Example 22 also illustrates the effect of a porous separation membrane with respect to o the relative filtration rate of the multi-component membrane. The coating material has a determined internal separation factor for separating hydrogen from carbon dioxide of about 0.3 to 0.4 (i.e., carbon dioxide passes faster than hydrogen) and yet the multi-component membrane has a separation factor for separating hydrogen from carbon dioxide of 2.3. This value is substantially the same, within the range of the experimental error, with the determined internal polysulfone separation factor for the separation of hydrogen from carbon dioxide.

Example 23

Example 23 (Table 6) shows the permeability values of a multi-component membrane (P / L) for a number of gases, the porous polysulfone separation membrane being in the form of a hollow fiber. Example 23 also shows permeability values for the same gases when passing through a continuous (i.e., continuous) compact film of polysulfone material. The ratio of any two P or P / L values defines the approximate separation factor for these gases when passing through a compact film or multi-component membrane. This example illustrates a clear tendency that the permeability of multi-component membranes usually varies from gas to gas in the same order as the permeability of a polysulfone compact film. This tendency suggests that the material of the porous separation membrane contributes significantly to gas separation by means of a multi-component membrane. This example shows that a multi-component membrane can be used to separate any gases from one another. The table below shows, for example, that ammonia from hydrogen or nitrogen, helium from methane, nitrous oxide from nitrogen, oxygen from nitrogen or hydrogen sulphide from methane can easily be separated using the multi-component membrane according to the invention. The advantages of these multicomponent membranes according to the invention reside in the high filtration rates, which is confirmed by the values given in Table 6 below.

Table 6

Permeability ^{3 of a} multi-component membrane consisting of a polysulfone porous separation membrane ⁵ and a compact polysulfone ⁰ film for various gases

Gas Multicomponent Polysulfone ⁰ membrane ⁵ continuous compact

P / l (.10 ⁶ ) ^and film, P (.10 ¹¹ ) ^and

NH3 210 530 Hs 55 130+ Не 55 50 N2O 45 82 CO.2 38 69 H2S 31 31 02 / 8.3 11 Ar 3.3 4.5 CH4 2.3 2.5 WHAT 2.4 3.2 N2 1.4 1,8 C2H4 1.7 2.2

^{and the} permeability of the multicomponent membrane is the P / L value expressed in units given in Table 1, cf. note a. The permeability of the polysulfone compact film is a P value, since 1 or the thickness of the compact film is readily measurable. The unit P is cm ³ / cm ² . with 1.3 kPa.

The multicomponent membrane in this example is a porous polysulfone separation membrane coated with post-cured silicone rubber, such as in Example 15, using the coating procedure F described in Table ^16c see Table 2, note b ⁺ for assay a hydrogen film other than that used to determine the permeability of the other gases was used.

Examples 24 to 26

These examples are comparative and do not fall within the scope of the present invention.

Table 7 below shows the results of Examples 24-26, which illustrate that not all composite membranes are within the scope of the present invention, i.e., they do not represent multi-component membranes having a separation factor substantially greater than the stated internal the separation factor of the coating material, although they are composed of porous separation membranes and coating materials, which may be used together with other coating materials or porous separation membranes to produce multi-component membranes of the present invention.

Example 24 shows a multi-component membrane of a porous polysulfone separation membrane coated with a pre-vulcanized silicone rubber. Since the pre-vulcanized silicone rubber has too large a molecular size to form an occlusive contact according to the invention, for example, the molecules can only link the pores of the bridge, the coating will not change the resistance in the pores to the gas flow. In Example 24, the coating material is a pre-cured polymer with the same polymer backbone as the post-cured silicone rubber, see for example Examples 11, 14 and 15 and Table 3. However, the pre-cured silicone rubber has a much higher molecular weight and molecular size due to pre-vulcanization in comparison with said post-vulcanized silica.

Table 7 with lean rubber and apparently cannot fill the pores, suggesting that the composite membrane has a separation factor equal (within the experimental error) to the separation factor of the coating material.

Example 25 illustrates a multi-component membrane wherein the coating material is additionally vulcanized silicone rubber and wherein the porous separation membrane is of polyacrylonitrile. Polyacrylonitrile in a continuous non-porous form has a very low gas permeability. With respect to this model, the porous separation membrane will have a very high resistance to the flow of gas through the solids (see solids 2 of Fig. 1), so that occlusal contact with a high permeability coating material such as for example, post-cured silicone rubber, the gas flow is predominantly through the coating and the filled pores. The multi-component membrane then has a separation factor equal to or less than the membrane coating separation factor.

The multicomponent membrane, illustrated in Example 26, has a separation factor lower than the determined internal separation factor of the coating material. This situation is similar to that in Example 24 in that the polyvinyl butyraldehyde used as a coating material has a high molecular weight. In addition, it does not wet the polysulfone as well as many silicones and other preferred coatings. Furthermore, polyvinyl butyraldehyde has a relatively low permeability. The finding that the separation factor of the multi-component membrane is lower than the expected separation factor of the coating material presupposes imperfections in the coating itself.

Example 24 (not within the scope of the invention) coating: pre-cured silicone rubber porous hollow fiber membrane: commercially available polysulfone treated gas concentrated gas (filtrate) coating process ³ determined internal separation factor ^b coating material permeability ^c porous separation membrane separation factor ^b porous separation membranes separation factor ^b multicomponent membranes permeability ^c multicomponent membrane air oxygen E separation 02 from N2: 1,7 for air: 1,8.10 “ ⁴ O2 separation from N2: 1,0 O2 separation from N2: 1,61 for O2: 4.1.10 ~ ⁵

257751 ' 55 Table 7 (continued) 56

Example 25 (not within the scope of the invention) coating: post-vulcanized silicone rubber porous hollow fiber membrane: polyacrylonitrile

Processed gas Concentrated gas (filtrate) Coating process ⁸ Determined internal separation factor * ³ Coating material Permeability * Porous separation air oxygen F O2 split from N2: 2.3 membrane separation factor ¹³ porous for air: 2.3.10 ~ ³ separation membranes separation factor * ³ multicomponent membranes permeability * multicomponent membranes O2 split from N2: 1,0 O2 split from N2: 1,9 for oxygen: 1,7.10 ~ ^s

Example 26 (not within the scope of the present invention) coating: polyvinyl butyraldehyde porous membrane in the form of a hollow fiber: commercially available polysulfone treated gas concentrated gas (filtrate) coating process ⁸ determined internal separation factor ^b coating material permeability * porous separation membranes separation factor * ³ porous separation membranes separation factor * ³ multicomponent membranes permeability * multicomponent membranes ^and see table 1, note d * 'see table 1, note e ^e see table 1, note and air oxygen

C separation of O2 from N2: 4.7 for air: 1.8. 10 ~ ⁴ O2 split from N2: 1,0 O2 split from N2: 4,0 for O2: 1,4.10

Examples 2 7 to 3 4

The results of Examples 27-34 are shown in Table 8. These examples illustrate a series of porous separation membranes that have been post-treated after spinning, and methods for influencing the separation properties of multi-component membranes made of post-treated porous separation membranes. membranes. The coating material and application methods shown in Table 8 are substantially identical, in order to confirm that changes in the filtration rate and separation factor of the multicomponent membranes (both for treated air and for the СО / Нг gas mixture) were due to changes in the relatively dense regions of the porous separation membrane. It is believed that the processing can affect the accessible pore cross-sectional area (As) relative to the total surface area (A2 + A3) of the porous separation membrane. Decreasing the value of Аз relative to the total surface area will increase the relative pore resistance of the porous separation and multi-component membranes to the gas flow. This in turn will force the filtered gas to pass more through the porous separation membrane material and the separation factor of the multi-component membrane will approach the internal separation factor of the porous separation membrane material.

^; In all the examples in Table 8, the porous separation membrane is a porous hollow fiber polysulfone membrane that has been wet-spun from a dope containing 25% solids in dimethylformamide as solvent to an aqueous coagulant at a temperature of about 3 ° C using a nozzle with a tube into which water was injected and the fiber was wound at a speed of 21.4 m / min. The porous separation membrane used in each of the examples was kept in deionized water at room temperature for spinning until further processing.

2 57 7 51

Table 8

Post-processing of the hollow fiber membrane

The multicomponent membranes of Examples 27-34 contained a post-vulcanized silicone rubber coating applied by coating method F, see Table 16. The post-spinning of the hollow fiber membrane was performed after spinning but before the coating was applied.

Example 27 post-treatment process gas concentrated gas (filtrate) permeability * multi-component membranes separation factor ⁶ multi-component membranes permeability · porous separation membranes after post-treatment separation factor ⁶ porous separation membranes after post-treatment

Example 28 post-treatment process gas concentrated gas (filtrate) permeability ¹ multi-component membranes separation factor ⁶ multi-component membranes permeability ³ porous separation membranes after post-treatment separation factor ⁶ porous separation membranes after post-treatment

Example 29 post-treatment process gas process gas (filtrate) permeability ³ multi-component membranes separation factor ⁶ multi-component membranes permeability ³ porous separation membranes after post-treatment separation factor ⁶ porous separation membranes after post-treatment evaporation of water in air air oxygen for oxygen: 1.5.10 ⁵ O2 division from N2: 4.7 for air: 3.7.10 * ⁴ O2 division from N2: 1.0 water evaporation in air

СО, H2 H2 for H2: 7,6.10 * ⁵ H2 separation from CO: 23,1 for H2: about 2,0.10 * ⁴ H2 separation from CO: about 2,6, evaporation of water in air; followed by exposure of the fiber to acetone vapor at 25 ° C under internal vacuum in the hollow fiber; then alternating immersion in water and methanol under internal vacuum in the hollow fiber (3 cycles); then alternating immersion in water and isopropyl alcohol (2 cycles) air oxygen for oxygen: 7.7.10 * ⁶ O2 separation from N2: 5.3 for oxygen: 3.5.10 * ⁵ O2 separation from N2: 1.0

Table 8 (continued)

Example 30 post-treatment process gas concentrated gas (filtrate) multi-component membrane permeability multi-component membrane separation factor ³ permeability of the porous separation membrane after post-treatment separation factor ^{11 of the} porous separation membrane after post-treatment

Example 31 aftertreatment process gas concentrated gas (filtrate) permeability ^{11 of} multi-component membrane separation factor ¹¹ multi-component membrane permeability "porous separation". after the post-treatment membrane, the separation factor ^{11 of the} porous post-treatment membrane

Example 32 post-treatment process gas concentrated gas (filtrate) multicomponent membrane permeability separation factor ^b multicomponent membrane permeability of the porous separation membrane after post-treatment separation factor ^{11 of} post-treated porous water-air evaporation separation membranes; followed by exposure of the fiber to acetone vapors. at 25 ° C under internal vacuum in the hollow fiber; then alternating immersion in water and methanol under internal vacuum in the hollow fiber (3 cycles); then alternate immersion in water and isopropyl alcohol (2 cycles)

CO, Нг

H2 for Нг: 4,5.10 ~ ⁵ division of H2 from CO: 30,4 for H2: 1,5. 10 ' ⁴ H2 separation from CO: 5.1 evaporation of water in air; followed by heating in a hot air furnace at 80-95 ° C for approximately 3 hours air oxygen for oxygen: 1,6,10 ^-5 O2 separation from N2: 5,0 for air: 3,7.10 ~ ⁴ O2 separation from N2: 1.0 water evaporation in air; then heating in a hot air oven at 80-95 ° C for approximately 3 hours CO 2, H 2

Ngg for Ngg: 9.8. 10 ~ ⁵ separation of H2 from CO: 23 for H2: about 2.5: 10 ^-4 division Нг from CO: about 1.3

Example 33 aftertreatment process gas concentrated gas (filtrate) multi-component membrane permeability separation factor ^b multi-component membranes permeability ³ post-treated porous separation membranes separation factor ⁶ post-treated porous separation membranes

Example 34 aftertreatment process gas concentrated gas (filtrate) permeability * multi-component membranes separation factor ⁶ multi-component membranes permeability ³ post-treated porous separation membranes separation factor ⁶ post-treated porous separation membranes ^and see Table 1, Note and ⁶ See Table 1 , note e.

drying by exchanging water with isopropyl alcohol, then exchanging isopropyl alcohol with pentane, then evaporating pentane in air air oxygen for oxygen: 2,0.10 ' ⁵ division O2 from №: 4,2 for air: 1,5. 10 ³ separation of O2 from N2: 1,0 drying by exchange of water with isopropyl alcohol, then exchange of isopropyl alcohol with pentane, then evaporation of pentane in air

СО, H2

H2 for H2 = 1.2. ⁴ “ ⁴ division of H ₂ from CO: 15.9 for H2: about 2.5. 10 ^-4 H2 separation from CO: about 1.3

Examples 35 to 39

The results of Examples 35-39 are shown in Table 9, which illustrate the effect of the additives contained in the coating material on the separation factor of the multi-component membrane when separating the two gas mixtures (air and CO / H2). These additives were added to the coating material in small amounts prior to application of the coating to the porous separation membrane. These additives may alter the separation properties of the multicomponent membranes, for example by changing the wetting properties of the coating material. This affects its ability to make occlusive contact with the porous separation membrane. If the additive improves occlusal contact, then the separation factor of the multi-component membrane containing the additive should approach the internal separation factor of the porous separation membrane material more than the separation factor of a similar multi-component membrane that does not contain the additive.

All porous hollow fiber separating membranes used in Examples 35 to 39 originated from the same winding coil and were made of commercially available polysulfone in highly porous form (see note et al., Wherein the spinning process was the same as the hollow spinning process). The internal separation factor of polysulfone for the separation of oxygen from nitrogen from air is about 6.0 and the partition of hydrogen from carbon monoxide from the CO / H2 mixture is about 40.

СО

Table б. 9

Effect of additives in coating material on separation factor of multicomponent membrane

Example # 35 36 37 38 ^e 39 ^e coating polydi- polydi- polydi- in advance in advance methyl- methyl methyl vulkani- vulkani- siloxane siloxane siloxane zovaný si- zovaný si- likonový likonový rubber rubber coating additive - 0.2% g-al- 0,4% fe- - 4,3% vul- material ¹ ' vinoxyl residue ^d nanthrenu of the lubricating agent (silicone polymer) separation factor ”multicomponent membranes (separation Ozod N2) separation factor” 3.0 to 3.3 4.9 4.8 3.9 4.4 multi-component membranes (H2od CO division) 3.8 16.5 10.7 14.6 20.5

^and all multicomponent membranes in Examples 35-39 contained a polysulfone separation membrane that was highly porous prior to coating. All percentages are percentages by weight ^c see Table 1, Note e ^{d The} galvinoxyl residue is a commercially available raw material and its structure is following:

^The components of the silicone rubber component have determined internal separation factors of 2.3 for the separation of oxygen from nitrogen and 1.1 for the separation of carbon monoxide.

Examples 40 to 43

The results of Examples 40-43, which are shown in Table 10, illustrate multi-component membranes whose porous separation membranes were produced under various spinning conditions. The multicomponent membranes of Examples 40 to 43 were formed from a porous polysulfone separation membrane on which an additionally vulcanized silicone rubber coating was applied (see the pilling procedure F, Table 16). Porous membranes of polysulfone hollow fiber were spun by wet spinning said solution into an aqueous coagulant, said temperature and said rate of spinning, using a spinneret having a nozzle for injecting into the cavity Lanta coagulation, the fiber ¹ during its formation. The range of permeability (Оз and H2) and the separation factors of the multi-component membranes for separating oxygen from nitrogen and separating hydrogen from carbon monoxide, as shown in Examples 40 to 43, either for treated air or for CO / H2 mixture, and a porous separation membrane material to the gas flow. The characteristics of the porosity and the effective separation thicknesses of the substrate are largely determined by the conditions under which the material was spun. These characteristics may vary depending on the post-spinning processing of the porous substrate (see Examples 27-34).

Spinning conditions for porous hollow fiber polysulfone separation membranes

Example 40

Table 10 Solvent Coagulation Temperature (° C) Spinning Rate Spinning Solution Concentration (wt% Polymer) Separation Factor » ^b Multicomponent Membrane (O2 separation from N2) permeability * for · O2 Separation Factor ^b Multicomponent Membrane (separation Ha from CO) permeability * for H2 permeability * porous air separation membranes

Example 41 solvent coagulation temperature spinning rate spinning solution concentration (% by weight of polymer) separation factor ^b multicomponent membrane (O2 separation from N2) permeability * for oxygen separation factor ^b multicomponent membrane (H2 separation from CO) permeability * for hydrogen permeability ³ porous separation membranes for air

Example 42 dimethylformamide

21.4 m / min%

4,5

7.7.10- °

16.7

5.0. ⁵ ' ⁵

6.ΙΙΓ ⁴ Dimethylformamide ^C C

21.4 m / min%

5.09.

6.2. 10 ~ ⁶

4.9. 10-5

9.ΙΟ ⁴ solvent coagulation temperature spinning rate spinning solution concentration (% by weight of polymer) separation factor ^{b of} multicomponent membrane (separation of O2 from N2) permeability * for oxygen separation factor ^{b of} multicomponent membrane (separation of H? From CO) permeability * for hydrogen permeability * porous air separation membranes

Example 43 solvent coagulation temperature spinning rate spinning solution concentration (% by weight of polymer) separation factor ^b multicomponent membrane (O 2 separation from N2) permeability * for oxygen separation factor ^b multicomponent membrane (H2 separation from CO) permeability * for hydrogen permeability * porous separation air membranes * See Table 1, Note a ^b See Table 1, Note e.

dimethylformamide

5 ° C m / min%

5.9

8,0.10 ' ^β

5.9. ΙΟ *. 10 ' ⁴ dimethylformamide ^C C m / min%

5.6

6,0.10 ^G

3.8.10 ' ⁵

4,5. ⁴ “ ⁴

Examples 44 to 51

Examples 44 to 51, the results of which are shown in Table 11, illustrate multi-component membranes of the invention wherein the porous separation membranes in the shape of an anisotropic acrylonitrile styrene copolymer had an internal separation factor for separating hydrogen from carbon monoxide 76. The films were cast from solvents containing dimethylformamide and an insoluble component as indicated in the table to

Table 11

Film-shaped multicomponent membranes Example 44 Coating porous separation membrane Process gas Coating process® Determined internal separation factor ^{b of} coating material (Нг separation from CO) Separation factor ^b Porous separation membrane (Hz from CO) Separation factor ^{b of} multi-component membrane (H2)

Example 45 Coating:

porous seiparation membrane process gas pustup coating ¹ determined internal separation factor ¹ 'of coating material (H2 separation from CO) separation factor ¹ ' porous separation membranes, (separation from Hz from CO) separation factor ' ^{1 from} multi-component membranes (separation from Hz from CO)

Example 46 Coating Porous Separation Membrane Process Gas Coating Procedure Determined Internal Separation Factor ^{b of} Coating Material (H2-CO Separation) Separation Factor ^{b of} Porous Separation Membrane (Hz-CO Separation) Separation Factor ^{b of} Multicomponent Membranes (Hz-CO Separation) Plate Desolvated in air for 5 to 45 seconds, coagulated as described below and then immersed in water at 25 ^and C, washed, removed and dried. Examples 48 to 51 illustrate multicomponent membranes in the form of dense films. These examples illustrate multicomponent membranes of the invention that are film-shaped and may also include porous release membranes having coatings on both surfaces.

additionally vulcanized silicone rubber copolymer acrylonitrile and styrene in a ratio of 32: 68 (weight%) ^c H2, CO

В

1.9

34.8 polydimethylsiloxane copolymer of acrylonitrile and styrene in a ratio of 32:68 (w / w) ^d

Hz, CO

В

1.9

12.2

23.8 additionally cured silicone rubber copolymer acrylonitrile and styrene in a ratio of 32: 68 (weight%) ^e Hz, CO

В

1.9

4.0

23.5 Polydimethylsiloxane akrylonltrilu copolymer and styrene in a ratio of 32:68 (weight ° / o] ^of polydimethylsiloxane

H2, CO

В

1.9

Example 47 Coating Porous Separation Membrane Coating Process Gas Coating Method Determined Internal Separation Factor ⁶ Coating Material Separation Factor ⁶ Porous Separation Membranes (Hz-CO Separation) Separation Factor ⁶ Multicomponent Membrane Coated on One Side (Separation №od CO) Multicomponent Separation Factor ⁶ membranes coated on both sides (separation of H2 from CO)

Example 48 Coating Porous Separation Membrane Process Gas / Concentrated Gas Coating Procedure * Determined Internal Separation Factor ^{6 of} Coating Material Separation Factor ⁶ Porous Separation Membrane Separation Factor ^{6 of} Multicomponent Membrane

EXAMPLE 49 Coated Gas / Concentrated Gas (Filtrate) Porous Separation Membrane Coating Procedure ³ Determined Internal Separation Factor ^{6 of} Coating Material Separation Factor ⁶ Porous Separation membrane Separation Factor ^{6 of a} multi-component membrane.

Example 50 Coating Porous Separation Membrane Processed Gas Concentrated Gas (filtrate) Coating Procedure ³ Determined Internal Separation Factor ^{6 of} Coating Material Separation Factor ⁶ Porous Separation Diaphragm Separation Factor ^{6 of} Multicomponent Membrane

3.4

7.6 additionally cured silicone rubber 25: 75 acrylonitrile: styrene copolymer (weight%) air oxygen

E

2.3 O2 separation from N2: 3.6 O2 separation from N2: 5.4 polydimethylsiloxane polymer blend of two acrylonitrile styrene copolymers air oxygen

AND

2.3 O2 separation from N2: 4.9 O2 separation from N2: 6.1 polydimethylsiloxane acrylonitrile: styrene copolymer in a ratio of 32: 68 (weight%), suspension polymerization air oxygen

AND

2.3 O2 splits from N2: 1.0 O2 splits from N2: 6.3

Example 51 Coating of a gas-treated porous separation membrane. concentrated gas (filtrate) coating process ^and provided for in he internal separation factor ¹ 'coating material separation factor ^b of the porous separation membrane separation factor of ^1' multicomponent membrane ^iJ see table no. 16 ^b see Table no. 1, note e polydimethylsiloxane copolymer of acrylonitrile and styrene in ratio 32: 68 (weight%); polymerization in air oxygen block

AND

2.3 O2 separation from N21: 3.6 O2 separation from N2: 4.9 ^L coagulation carried out in 50:50 by volume ethylene glycol-water for 30 minutes at 25 ° C coagulation carried out in isopropyl alcohol mixture - water in a ratio of 90: 10 parts by volume for 30 minutes at 25 ° C ^e coagulation carried out in isopropanol / water in a ratio of 10: 90 parts by volume for 30 minutes at 25 ° C coagulation carried out in water at 25 ° C ^fJ C.

Examples 52 to 57

Examples 52-57 illustrate several multi-component hollow fiber membranes. The porous hollow fibers can be produced by wet spinning as mentioned above. The polycarbonate fiber of Examples 52 and 53 was spun by a spinning solution method of a spinning solution consisting of 27.5% by weight of polycarbonate in N-methylpyrrolidine, into an aqueous coagulant at 25 ° C at a rate of 21.4 meters / min. The polysulfone hollow fiber of Example 54 was spun from a spinning solution consisting of 27.5% by weight of polysulfone in a solvent mixture (dimethylacetamide-acetone 80:20) to an aqueous coagulant at 2 ° C at a speed of 21.4 m / m. min. The fiber of the acrylonitrile-styrene copolymer of Example 55 was spun from a spinning solution consisting of 27.5% by weight of the copolymer in a mixture of solvents (dimethylformamide-foirmamide in a ratio of 80:20) to an aqueous coagulant at 3 ^° C at a rate of 21 ^° C. 4 meters / min. The acrylonitrile-styrene copolymer fiber of Examples 56 and 57 was spun from a spinning solution consisting of a 25% w / w copolymer in the same solvent mixture as in Example 55 into an aqueous coagulant at about 20 ° C at a speed of 21.4 m. / min. The results of the testing of multi-component hollow fibers in the separation of the hydrogen-carbon monoxide mixture are shown in Table 12 below.

Table 12

Example # 52 53 54 process gas additionally vulcanized silicone rubber polycarbonate Hz, CO block copolymer of α-methylstyrene and dimethylsiloxane polycarbonate Hz, CO block copolymer of α-methylstyrene and dimethylsiloxane polysulfone Hz, CO coating process ^c F D D determined internal separation factor ^{0 of} coating material (separation of Hz from CO) 1.9 2.1 2.1 separation factor of porous separation membrane (separation of Hz from CO) 3.29 1.3 3.0 separation factor ^{d of} multicomponent membrane (separation of H2 from CO) 7.5 9.4 15.6 permeability ”of multi-component membrane (Hz) 4.41 · 10 ' ⁵ 9,95.10 5 6.7.10 ~ ⁵ permeability of ³ porous separation membranes (for Hz) 2,58.1СГ ⁴ 5.3. 10 ~ ⁴ 4.8. ΙΟ ⁴ determined internal separation factor ^b of porous separation membrane material (separation of H2 from CO) 23.2 23.2 40 ^and see Table 1, Note a, ^d see Table 1, Note e, 'see Table 1, Note a ^{, J} continuous film separation factor from a given material Example 55 56 57 process gas post-cured silicone rubber acrylonitrile-styrene copolymer (33: 67), post-treated with methanol, dried Hz, CO post-cured silicone rubber acrylonitrile-styrene copolymer (44: 56), post-treated with methanol, dried Hz, CO additionally cured silicone rubber acrylonitrile-styrene copolymer (44: 56) without additional processing Hz, CO coating procedure ¹ F F F determined internal separation factor ^{d of} coating material (separation of H2 from CO) 1.9 1.9 1.9 separation factor ^{0 of} porous separation membrane (separation of H2 from CO) 3.0 3.2 separation factor ^{d of} multicomponent membrane (separation of H2 from CO) 32 67.5 17 permeability of ³ multi-component membranes (Hz) 3,2.10-5 1.9.1O ~ ⁵ 4,46.10'5 permeability of ³ porous separation membranes (for H2J 2.9. ⁴ “ ⁴ __ 3,4.10-4 determined internal separation factor ⁶ of porous separation membrane material (separation of Hz from CO) 85 about 100 about 100 ³ see Table 1, Note a, ^c see Table 16, ^b see Table 1, Note e

^b a continuous film separation factor from said material

СЕ

Example 58

This example illustrates a multi-component membrane of the invention having a multiple coating to achieve the desired separation factor. A hollow fiber porous separation membrane (63% acrylonitrile and 37% styrene copolymer) was made by wet spinning from a solution containing 27.5% by weight of the copolymer in dimethylformamide / formamide (93: 7) to water at 2 ° C. at 21.4 m / min. This fiber was first treated by immersion in methanol under vacuum under vacuum in the fiber cavity, then dried and reprocessed with methanol and dried. The dried fiber was then coated according to procedure D (see Table 16) with poles (cis-isoprene) in pentane, cured for 30 minutes at 85 ° C and then coated with a 10% post-vulcanized silicone rubber solution in pentane according to Procedure F (see Table 16). The coated substrate was then re-coated with a (cis-isoprene) solution, dried. and re-coated with a solution of post-cured silicone rubber, and then cured for 30 minutes at 90 ° C, 30 minutes at 100 ° C and finally 35 minutes at 105 ° C. The results of the testing of uncoated porous multi-component membranes and multi-coated multi-component membranes are shown in Table 13 below.

Table 13 determined internal separation factor of coating material (separation of H2 from CO) separation factor ^{b of} porous separation membrane (separation of CO from CO) separation factor * ⁵ multicomponent membranes (separation of H2 from CO) separation factor ^b multicomponent membranes (separation of H2 from CO ) permeability ^and porous separation membranes (for H2) permeability ^and multi-component membranes (for H2) determined internal separation factor ⁰ of porous separation membrane material (H2 separation from CO) cis-isoprene 3.5 additionally cured silicone rubber 1.9

5.09

2.65. 10-5

6.5. ΙΟ ⁷

320 ^a see Table 1, Note a ^b See Table 1, Note e ^c Separation factor of continuous film from given material

Examples 59 and 60

Examples 59 and 60 illustrate multi-component membranes having a porous separation membrane of brominated polyxylylene oxide, and the porous separation membrane is hollow fiber coated and coated. This hollow fiber was produced by wet spinning from a spinning solution consisting of 30% by weight polymer in N-methylpyrrolidone to an aqueous coagulant at 85 ° C at a rate of 14.8 L / min. According to Example 59, the thickened polyxylylene oxide in which substantially methyl groups were brominated was coated without further processing after spinning. In Example 60, the brominated polyxylylene oxide was post-treated by soaking for 20 hours in a 10% aqueous solution of trimethylamine. In both examples, a silicone rubber coating was applied and applied by the V process (see Table 16). The results obtained are shown in Table 1-4.

2: 5 77 51

S7

Table 14

Example

additionally vulcanised silicone rubber additionally vulcanised silicone rubber determined internal separation factor ^{6 of the} coating material thickened polyxylylene oxide brominated polyxylylene oxide, post - treated with (CH3J3N (Hz-CO separation) Separation Factor ^{6 of the} porous separation membrane 1.9 1.9 (separation of H2 from CO) multicomponent separation factor 1.48 2.85 membrane (separation of H2 from CO) permeability ³ multicomponent 11.1 9.59 membrane (for H2) permeability ³ porous separation 9.58.10 ~ ⁵ 1,27.10 ⁵ membrane (for H2) the determined internal separation factor ⁰ of the porous separation membrane material [division] 1,25.1СГ ³ 3.83. ⁵ ' ⁵ H2 from CO3 ³ see Table 1, Note and ⁶ See Table 1, Note e 15 Dec 34 ^c a continuous film separation factor from the material

Example 61

In this example, a multicomponent membrane according to the invention is illustrated in which a porous hollow fiber-shaped brominated polyxylylonoxide-like porous separation membrane has been provided in various ways. The hollow fiber of polyoxylylene oxide of Example 59 was post-treated by soaking for about 70 hours at 50 ° C in a 5% (w / w) solution of thiourea in water-methanol (95: 5 by volume). After drying, the hollow fiber membrane was coated with a 5% solution of silicone rubber in pentane by Procedure F (see Table 16). By testing the post-treated hollow fiber porous separation membrane and the coated multi-component membrane, the following results were found: _t determined internal separation factor ^{6 of} coating material (H2 separation from CO) 1.9 separation factor ⁶ porous separation membrane (separation) *

H2 from CO) 5,6 separation factor ⁶ multicomponent membranes (division from CO) 46,1 permeability ³ multicomponent membranes for H2 '7,2.10 ⁶ permeability ³ porous separation membranes for H2 3,9.10 ~ ⁵ determined internal separation factor ^{0 of} material porous separation membranes (H2 to CO separation) of about 150 ^and see Table 1, Note a ^b See Table 1, Note e ^ Continuous film separation factor from the material

Examples 62 and 63 These examples illustrate the broad applicability of the multi-component membranes of the invention, showing that the coating can be formed on the outer or inner and outer surfaces of the porous hollow fiber membrane. These examples also illustrate a gas separation process wherein the gas mixture to be treated was a mixture of hydrogen and carbon monoxide and the mixture was contacted with the opposite surface of the multicomponent membrane to which the coating was formed. In Example 62, a porous hollow fiber polysulfone separation membrane was coated on the inner surface with a three-percent solution of silicone rubber in pentane by slowly pumping the solution through the hollow fiber opening and leaving the fiber to flow through the silicone rubber flow by F (see Table 16). . The results of these two examples are shown in Table 15 below.

air dry. Permeability was determined by filtering the H 2 / CO mixture from the outer surface into the cavity of the resulting membrane. In Example 63, the hollow fiber of Example 62 was additionally coated with the same blank No. 15

Example determined internal separation factor ^{0 of} coating material (separation of H2 from CO) separation factor ^{c of} porous separation membrane (separation of H2 from CO) separation factor ^{0 of} multicomponent membrane (separation of H2 from CO) permeability ¹ 'multicomponent membrane (for I-I2) permeability ⁶ porous separation membranes (for H2) additionally vulcanized silicone rubber polysulfone ³ (coating only in the fiber cavity)

2.3

3.23

22.0

3.6. 10 ~ ⁵

2,06.10 additionally cured silicone rubber polysulfone ³ (coating both in the cavity and on the outer surface of the fiber)

2.3

3.23

21.2

2.31. ⁵ ' ⁵

2.06. ^{4 4} pol polysulfone commercially available wet-spun from a spinning solution containing 30% by weight of polysulfone in a dimethylformamide / N-methylpyrrolidone (50:50) solvent mixture to water at 2 ° C at a rate of 21, 4 m / min and taken after washing and tensioning at 33 m / min ^b see Table 1, Note a ^c See Table 1, Note e

Example 64

This example illustrates a method for manufacturing a multi-component hollow fiber membrane comprising a polysulfone porous separation membrane and a coating of post-cured silicone rubber. The commercially available polysulfone polymer was dried for about 25 hours at a temperature of 100 ° C and a pressure of about 20 psi. The dried polysulfone was mixed with dimethylacetamide (moisture content less than about 0.1 wt%) at a temperature of about 65-70 ° C to provide a solution containing 27.5 wt% polysulfone. This solution was then transferred to a storage vessel under a nitrogen atmosphere at a pressure of about 1 bar. The solution was not heated in the tank, so it was cooled to room temperature.

The polymer solution was then pumped from a storage vessel into a hollow fiber spinneret which was immersed in a water bath at about 4 ° C. The spinneret had an outer nozzle diameter of 0.0559 centimeter, an inner tube diameter of 0.0229 cm, and a nozzle diameter of 0.0127 cm. The polymer solution was pumped into the spinneret while measuring the velocity to a speed of about 7.2 mm / min, and the fiber advanced from the spinneret at a rate of about 33 m / min. The polymer solution coagulated into a hollow fiber upon contact with a water bath. Distilled water was fed through the spinneret nozzle to coagulate the interior of the hollow fiber. The fiber was passed through a water bath on a path of about one meter. The water bath was continuously cleaned to keep the concentration of dimethylacetamide in the bath less than about 4 wt%.

The fiber was then immersed in a second water bath maintained at about 4 ° C. The fiber was routed through the bath for about five meters. After leaving the second water bath, the fiber still contained some dimethylacetamide.

The fiber that was discharged from the second water bath was immersed in two other water baths at ambient temperature, each of which was guided along a path of about five meters. The fiber was wound on a spool, but only under a tension that was just sufficient to wind. The fiber was wetted with water during winding, and after winding the fiber, the bobbin was immersed in a water tank, where it was left at ambient temperature. The fiber was then dried at ambient temperature, preferably at about 20 ° C and 50% relative humidity. The dried fiber was coated with an approximately 5% solution of silicone rubber in the form of a prepolymer containing dimethylsiloxane and a curing agent in n-pentane. The coating was applied by dipping the fiber into a prepolymer solution while keeping the solution under pressure. The fiber was allowed to air dry in a

5,775 l cross-linked to form a silicone rubber coating.

Table 16

Coating procedures

The A-hollow fiber porous membrane was immersed in undiluted liquid coating material. The excess liquid was allowed to drip.

The porous hollow fiber-shaped membrane was immersed in undiluted liquid coating material and a vacuum was created in the porous hollow fiber cavity. After removal of the fiber, vacuum was removed and excess liquid was allowed to drip.

The C-porous hollow fiber membrane was immersed in a liquid coating material diluted with a hydrocarbon solvent. The solvent was allowed to evaporate.

The hollow fiber shaped porous membrane was immersed in a liquid hydrocarbon solvent coating material while creating a vacuum in the hollow fiber cavity. After removal of the fiber, vacuum was removed and the solvent was allowed to evaporate.

The hollow fiber-shaped porous membrane was immersed in a solution comprising a coating material in the form of a polymerizable prepolymer, an appropriate curing agent, and a hydrocarbon solvent. The solvent was evaporated and the membrane prepolymer was cured.

The F-coating process was identical to that described in E, except that a vacuum was created in the hollow fiber cavity for as long as the hollow fiber was immersed in the coating solution.

Claims (6)

Multi-component membrane for the separation of gases, in particular for the separation of gases containing hydrogen, helium, ammonia, carbon monoxide, carbon dioxide, nitrogen, argon, sulfur hexafluoride, methane and ethane, consisting of a coating material in contact with a porous carrier; characterized in that the porous support is a porous separation membrane having a thickness of 200 to 500 μπι, the volume of which is 10 to 80% pores, and which consists of a polysulfone of the formula wherein n is 50 to 80 having at least k an internal gas separation factor of at least 35% greater than the internal gas separation factor of the coating material, and a polysiloxane thickness of 0.0001 to 50 µm of a coating material having an internal gas separation factor of less than is the determined internal separation factor of the multicomponent membrane, it is occlusive with a porous separation membrane. Multicomponent membrane according to claim 1, characterized in that the porous separation membrane is anisotropic. Multicomponent membrane according to Claim 1, characterized in that the coating consists of an aliphatic or aromatic polysiloxane having repeating units of 1 to 20 carbon atoms. Multicomponent membrane according to claim 3, characterized in that the coating consists of a polysiloxane which is crosslinked in the form of a silicone rubber and has a molecular weight of 1,000 to 100,000 before crosslinking. Multicomponent membrane according to claim 1, characterized in that, with respect to at least one of the gases selected from the group consisting of carbon monoxide, carbon dioxide The nitrogen, argon, sulfur hexafluoride, methane and ethane are effective multi-component membrane thicknesses of less than 1500 nanometers for said gas and the ratio of total surface area to total pore cross-sectional area of the porous separation membrane is at least 10 ³ : 1. 6. The multi-component membrane of claim 1, wherein the coating is in contact with both surfaces of the porous separation membrane and the coating in contact with each surface has an average thickness of up to 50 nanometers.