CN1024324C - Treatment of permeable membranes - Google Patents
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- CN1024324C CN1024324C CN 88108819 CN88108819A CN1024324C CN 1024324 C CN1024324 C CN 1024324C CN 88108819 CN88108819 CN 88108819 CN 88108819 A CN88108819 A CN 88108819A CN 1024324 C CN1024324 C CN 1024324C
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Abstract
The present invention relates to a method for controlling a reinforced gas separation membrane for a long time. An osmosis membrane is heated at the temperature of 50 DEG C to 140 DEG C. Penetrating quality which is degenerated in a gas separation process can be restored and regenerated by adopting the method.
Description
The invention relates to a kind of new method of strengthening through the gas separation membrane of long-term use.More particularly, the invention relates in the preparation that behind long-term gas lock out operation, has the infiltrative doughnut permeable membrane of raising, and the recovery of the Penetration Signature of film.This film since feed stream in impurity and at the operating process mesometamorphism.
Therefore permeable membrane can optionally make a kind of component in the mist see through, and in this technical field, has been considered to realize a kind of convenience that desired gas separates and device that the large development potentiality are arranged.For the industrial operation of reality, permeable membrane must reach an acceptable selectivity to the separation of all gases component contained in the feed stream, simultaneously, also will reach the higher isolated yield and the stability of an expectation.Yet, film system through the use that continues after, be subjected to the influence of impurities in the feed stream, reduced the operating characteristics of film, any solution of this difficult problem is all had very big importance industrial.
In order to realize all gases lock out operation, various types of permeable membranes have been proposed now.These films generally can be divided three classes: (1) isotropic membrane, (2) asymmetric film, (3) composite membrane, so-called isotropic membrane and asymmetric film mainly are made of single permeable membrane material, it is required component in the separating mixed gas optionally, the density of the whole film body of isotropic membrane is identical, the shortcoming that these films are general is that the saturating rate of infiltration is low, promptly because the thickness of its required film is relatively large, seepage discharge is less, and the difference of asymmetric film is that it has two zones that form is different on the structure of film.A zone wherein is made up of a thin and fine and close semi-permeable face, it can optionally see through a kind of component in the mist, another zone then is made of the Support of a non-densification, porous, non-selectivity, and it is used for preventing that the sake zone of film from collapsing under pressure.The formation of composite membrane generally is that suitable permeable membrane material thin layer or coating are stacked on the porous matrix.Described permeable membrane separation of thin layers has determined the stalling characteristic of composite membrane, and it is preferably extremely thin, so that the above-mentioned high osmosis energy of mentioning is provided.Described matrix is only as supporting the film of putting thereon.No matter the film of which kind of type in use all will be gone bad, thereby influence its gas permeability and/or selectivity reduces.
Along with permeable membrane update and perfect, to the also corresponding raising of the requirement of its operation.Therefore, the developing direction in this field should be, extremely thin film, and their penetration property improves, and does not influence again simultaneously to separate or selectivity characteristic.Therefore, to the separation of multiple industrial gasses, more and more wish to make in a long time high permeability to realize more satisfactory combining with selectivity.Simultaneously, also wish to improve or improve preparation and have the raising gas permeability, but do not reduce the optionally method of film, and recover in use since in the feed stream impurities cause the characteristic of the film that goes bad.
Though isotropic membrane generally should not satisfy the requirement that gas separates, and asymmetric film is updated, be used for actual gas and separate, but do not have a kind of intrinsic flexibility as a rule so that they easily carry out optimization in specific gas separates.In order to improve permeability, the semi-permeable compacted zone of specific asymmetric membrane material can be done thinlyyer, but meanwhile, at the separation of handled gas component in the special-purpose, the selectivity of described material may not reach requirement, unless improve with the particular processing technology.
Have now found that at the United States Patent (USP) 3,133 of Loeb, the thin surface of the asymmetric film of these described in 132 is normally faulty, but have a lot of defectives.These defectives are forms such as residual hole, pinprick, have constituted the relatively large hole in aperture, and the feed gas that passes membrane material will preferentially pass these holes.As a result, owing on membrane structure, have these defectives, feed gas and the mutual interference mutually of permeable membrane material own, the gas separating degree reduces greatly.For asymmetric ps hollow fiber uf membrane, when these defectives were arranged, (hereinafter definition) was 1 to 1.5 to the selectivity of air, and when not having these defectives, selectivity is 6.0.People such as Henis have proposed a kind of solution, in his United States Patent (USP) 4,230,463, disclose asymmetric film is applied, and coating material has an intrinsic separation of determining, its value is less than the separation of separation membrane material.Used coating step such as Henis is described in United States Patent (USP) 4,230, in the table X VI on 463 51-52 hurdle.This step comprises: porous hollow fiber membrane is immersed in (useable solvents is diluted or do not diluted) in the liquid coating material, makes excessive liquid coating material drippage then, make it evaporation when solvent exists.By this step, can make selectivity to air be about 2 silicone coating to polysulfone hollow fibre, thereby make its selectivity bring up to 2～6 from above-mentioned 1～1.5, selectivity generally reaches 6 like this.The permeability of these siloxanes/polysulfone composite membrane (hereinafter definition) is generally quite low, promptly is less than about 0.2 cubic feet (normal temperature-pressure)/square feet Pascal sky (followingly all to be abbreviated as: ft
3(STP)/ft
2Psi days), thus wish that film is thinner, and promptly thinner fine and close face is to be particularly suitable for the increasing requirement to the operation of present technique field high flow capacity.Yet thinner film will bring the increase of a series of defectives, and they need be repaired to operate normally.Along with keeping punching to this step is improved, people wish to have the other step that required selectivity, permeability and long-life reasonable combination is provided in the actual industrial operation.Owing to these reasons, composite membrane provides maximum chance, realizes that industrial specific gas separates the selectivity that will reach and the reasonable combination of permeability, and composite membrane has been selected the membrane material that is particularly suitable for the desired gas separation for use.In order to reach the operation requirement, composite membrane not only will have extremely thin rete, and pair separating layer matrix structure of desired gas lock out operation best results also will be arranged.One of commercial Application that these are important is that the separation of air, particularly membrane material optionally make the oxygen infiltration, reclaims as the oxygen enrichment infiltration gas, and nitrogen-rich gas is discharged as non-infiltration gas.Thereby exist really the exploitation composite membrane needs, with the particularly suitable air separation, and other required gas lock out operation, as recover hydrogen from ammonia purgative gas and refining air-flow, the carbon dioxide in various operations such as the tertiary process is separated with methane.
In order to realize these separation, many pellicles have been proposed, material that it is selected for use and form have varied.So-called composite membrane is that the thin layer with a suitable semipermeable membrane material is stacked on the matrix of relative porous.Separating layer is preferably extremely thin, so that above-mentioned high flow capacity to be provided.Matrix is that extremely thin and refining semi-transparent rete or stacked thereon coating provide support.These membrane structures are described in people's such as people's such as Salemme United States Patent (USP) 4,155,793 and Klass the United States Patent (USP) 3,616,607.
The permeable membrane that is used for the separation process of gas feed permeable membrane is required the rete or the perfection of separating layer height of film.Clearly, separating at gas is in the processes such as pervaporation, Perstruction, if rete does not have residual hole or other defective, free from admixture then will obtain best result.On the other hand, rete need be done thinly as far as possible and even as far as possible, obtaining needed high permeability, and the high yield of whole separation process.In these cases, the anomalad that exists is for often there being appearance such as residual hole, pinprick in the separation of thin layers of film device, normally each typical film preparation workshop section is as bringing in spinning, casting, coating, slaking and the film structural component preparation manipulation for these defectives, and impurity is brought by feed stream in can being to use.
For the problem of overcoming one's shortcomings, the United States Patent (USP) 3,980,456 of Browall discloses a kind of method, adopts second seal coating to be coated on as thin as a wafer the rete, to cover the defective that is caused by specific impurities.Composite construction characteristic complexity after treatment is in addition, general and fail not only to provide required separation selectivity but also the flow of infiltration gas or permeability are reduced greatly with being stacked in thin layer on the porous support matrix.
In people's such as Ward United States Patent (USP) 4,214,020, disclose a kind of method, it is immersed in a branch of doughnut in the coating solution, to apply on the outer surface of hollow fiber membrane device, skin by doughnut pressurizes to internal layer then, and coating solution is entered in the fiber.This method, cause forming one pantostrat/coating at the skin of doughnut, be specially adapted to use the coating solution material that gas is had high osmosis, coating has the asymmetric film in some residual hole, as the described method of people's such as above-mentioned Henis patent, thus preparation high-selective gas diffusion barrier.
United States Patent (USP) 4 people such as Arisaka, 127, in 625, a kind of method for preparing asymmetric hollow fiber is also disclosed, it is during the slurries of one one-tenth fiberized resin are condensed bath by the outer tube spinning of shaped double tube spinneret to a water, form a doughnut, simultaneously liquid, aqueous interior pipe ejection, with the interior side contacts of doughnut by this spinneret.In warm water, flood drying then.
United States Patent (USP) 4 people such as Riley, 243, in 701, disclose a kind of method that forms a kind of non-porous permeable membrane thin layer on the surface of porous supporting body again, it is that porous supporting body is passed through in the solution of a halogenated hydrocarbon solvent, and this solution contains permeable membrane, it is made of prepolymer and crosslinking agent, porous supporting body after the coating is taken out from solution, make prepolymer crosslinked under heating again, form composite membrane.
In people's such as Coplan United States Patent (USP) 4,467,001, the method and apparatus of a kind of coating, drying and a plurality of fibers of slaking is disclosed.Liquid coating is coated on the fibril with " U " shape pipe, dry, slaking on gaseous environment.
Should consider that also JEKoresh and ASofer are at " separating science and technology " (Separation Science and Technology, 18(8), PP723-734,1983) reach " penetration mechanism of carbon film of molecular sieve " (the Mechanism of Permeation Through Molecular-Sieve Carbon Membrane that on " the chemical faraday of association journal ", delivers in, J.Chem.Soc.Faraday Trans.1,1986,82, the 2057-2063) carbon film of molecular sieve described in.
Sell wholesale on July 2nd, 1974 in the United States Patent (USP) 3,822,202 of H.H.Hoehn, disclose a kind of to polyimides, polyamide and polyester polymers in vacuum, under at least 150 ℃-340 ℃ or higher high temperature, carry out the initial heat-treatment method.33 embodiment are wherein arranged, comprised 111 experiments, all carry out according to said invention, and in vacuum, 150 ℃-340 ℃, the time is to carry out under 1 minute to 6 hours the condition.Without any indication, making can be under lower temperature, the permeability of the film that recovery had been used in this patent.
" the auxiliary polyalcohol coating in the improvement of reverse osmosis membrane and the regeneration " (Supplemental Polymer Coatings in Reverse Oamosis Membrane Improvement and Regeneration at " desalination " book that GL.Dalton showed, Desalination, 24(1978) 235-248) in, described and a kind ofly handled the nonstandard or sex change cellulose acetate membrane of using in water and the separation process, made its insoluble method then with soluble polymer.This method requires to handle film with water-soluble aqueous solutions of polymers.In the 236th page, although the author points out to recover the desalting performance of the aqueous solution in separating with the heat treatment way, this method or technology itself can not be used this area simply.In contrast, the described method of the inventor of present patent application has been found very suitable applications way.
The technology of operating characteristic of handling the film that improves or recover to use in the fluid separation applications with various auxiliary agents is much, now discloses many.Sell wholesale on April 30th, 1974 in people's such as J.B.Ganci the United States Patent (USP) 3,808,303, molecule is added to greater than 400 ether (or water) in 50 ℃-90 ℃ the aqueous solution, absorbed until reverse osmosis membrane till the inorganic agent of effective dose.Sell wholesale on December 10th, 1974 in the United States Patent (USP) 3,853,755 of J.B.Ganci, the reverse osmosis membrane of poisoning is handled with 10 ℃-90 ℃ hydrolyzable tanning solution.Sell wholesale on May 27th, 1975 in people's such as C.Chen the United States Patent (USP) 3,886,066, non-porous pellicle contacts with 0 ℃-100 ℃, the Hydrolysable Tannins solution of pH value 1.5-6, and the initial solute flow by film is reduced.Shown the partial regeneration that is entitled as reverse osmosis membrane at one piece by D.B.Guy people " in (On-Site Regeneration of Reverse Osmosis Membranes; D.B.Guy et al.; WSIA magazine; 1982; Vol.9; No.1,35-43 page or leaf), tested with multiple material and handled film.All comprise method in all examples with the chemical substance treatment film.Similar techniques also is used and is disclosed on a publication that comprises the FLOCON product of the two parts of publications that comprise MT and AF product of GoodWill and Pfizer, and they clean or handle film with number of chemical reagent.In all examples, these methods all comprise uses one or more chemical reagent to handle film.
No matter how film prepares, all permeable membranes in use all can be gone bad, particularly under without the situation of preliminary treatment with the gas feed of removing residual volatile impurity such as lubricating oil and compressed oil steam or other impurity.Many effort are used so that activation recovering to a higher value.Yet so far, show industrial practicality, the permeability of a rotten permeable membrane and/or selectivity are returned to basically be at least the initial value of new film structural component without any method.Proposed or disclose under gentle relatively condition, to make film properties to recover without any a kind of in the method for above-mentioned discussion.In the past, done the effort that some makes performance recovery, but, therefore in practical operation,, then just removed this membrane module, with new replacement if permeability and/or selectivity no longer can reach requirement without any a kind of complete success.
The present invention is a kind of under quite gentle condition, by the heating permeable membrane, improves long penetration operation and/or makes the permeability of doughnut permeable membrane and/or the method that selectivity is recovered.This method is applicable to the permeable membrane of doughnut, spiral or any other desired structure.
The invention provides a kind of permeability that improves long-time penetration operation and/or gas separation membrane, the method that selectivity is reduced again, this method are applicable to new or with the processing of the gas separation membrane of crossing that is used for Selective Separation fluid mixture component.Permeable membrane is used for the component in the divided gas flow composition, as the Selective Separation of gas in the air.Method of the present invention both can be used as the prolongation penetration operation, can recover the permeability of pellicle in the gas separation process again.
Though record the method that washing method or method of chemical treatment gas separate the permeability properties recovery of used permeable membrane in the document; but the to the greatest extent understanding of our institute's energy does not have of the present invention and claimed method and gets the nod or relate in gas separation process.The present invention not only can prepare has permeability and/or the selectivity that higher initial gas separates, but also can be under quite gentle condition, the permeability of the film that these performances are gone bad in the use and/or selectivity are recovered, and film are not caused damage.This has great industrial value because so far again need not resemble existing frequent replacing film or film structural component (these materials cost usually are bigger), and make their permeability and/or selectivity return to its initial value, even higher than initial value.Can realize under the condition of a kind of so suitable mixing disclosed herein that this purpose is unexpected fully.
Because the permeable formation of film was extremely thin during gas separated, the trace impurity in use any gas raw material stream stockpiles on the film surface will cause permeability and/or optionally rotten.Heating can make impurity add in the feed stream with the hydrocarbon vapours of condensation dye thing and remove or desorb from the film surface.
Permeable membrane can heat separately, or with the film structural component heating, this is that those of ordinary skill in the art is to understand.Heating process can be carried out under dry or moistening condition, and it depends on handled specific film system.Heating-up temperature is about 80 ℃～140 ℃, preferably is about 100 ℃～125 ℃.Any temperature that is higher than 80 ℃ all can adopt in this scope, only otherwise damage porous supporting body or permeable membrane.In some cases, under vacuum, heat (as mentioned above) and/or to clean as nitrogen with inert gas be useful.It is invalid adopting vacuum separately.For this professional those of ordinary skill is clearly, and the used various polymer as film have different breaking-up temperature, and therefore these breaking-up temperature of the indication that Clicks here be should give and avoided.
Because many industrial process doughnut permeable membrane element, there is the termination of polymeric encapsulate its each end, so preferably it is placed in the baking oven when handling with the inventive method and heats, or makes thermal current pass through assembly to heat.In this way, dirt or impurity promptly are removed.When a new member.When making the heating of member or film carry out initial treatment as stated above, can be enough to usually improve initial permeability, and the permanent operation of reinforced film.For this professional those of ordinary skill, the preparation of doughnut permeable membrane element is known, and need not be further described, because doing detailed description in the publication now.This respect also can be with reference to United States Patent (USP) 3,442,002; 3,499,062; 4,207,192 and 4,631,128.
Accompanying drawing with graph direct the beat all result that the inventive method realizes has been described.Data among the figure are from comparative example I and embodiment 1 and 2, and it refers to the separation of gas in the air, pressure 100 Pascals, and 25 ℃ of temperature, all situations selectivity to oxygen separation between oxygen and nitrogen is 3.8.
Curve A in the accompanying drawing, based on embodiment 1, the rotten situation of the permeability of the doughnut film structural component that initial heating handles is not carried out in its expression by method of the present invention.Can see that the initial permeability of oxygen is about 0.39ft
3(STP)/ft
2Psi days.Operate after 400 hours, permeability drops to about 0.32ft
3(STP)/ft
2Psi days.In this stage, in an air circulation oven, recovered in 1 hour with 120 ℃ of temperature heating.Behind the film structural component cool to room temperature, proceed air separation.After processing finishes, just air separation at the beginning, the permeability of oxygen is raised to unexpected 0.54ft dramatically
3(STP)/ft
2Psi days, approximately exceed primary oxygen permeability about 40%.This permeability descends again after after a while, is stabilized in about 0.4ft then
2(STP)/ft
2Psi days.It is worthy of note handle after, permeability is stabilized in and equates with the initial value of untreated member or slightly on the high value.
Curve B in the accompanying drawing is based on embodiment 2, its expression be to adopt the mode identical in 120 ℃ of heating 1 hour down, the result who doughnut permeable membrane member is carried out the initial heating processing with used member in the curve A experiment.In this embodiment, the initial permeability of the oxygen of member is about 0.53ft after the heat treatment
2(STP)/ft
2Psi days, be much higher than the numerical value of curve A and curve C.Permeability reduces gradually, is stabilized in about 0.4ft then
3(STP)/ft
2Psi days.No matter it is worthy of note, be that member heats improving its initial permeability (curve B), or member heats recovering its permeability (curve A), and permeability all is stabilized on the roughly the same value at last.
Curve C in the accompanying drawing is based on the comparative example I, the situation of permeability when its expression film structural component is handled without method of the present invention.It is corresponding to present traditional operation.In this case, the primary oxygen permeability is about 0.39ft
2(STP)/ft
2Psi days.After operation in 325 hours, oxygen permeability drops to 0.3, is stabilized in about 0.33ft subsequently
3(STP)/ft
2Psi days.No matter be noted that under two kinds of situations that member is handled, be initial to improve its permeability, still subsequently to recover its permeability, the stationary value of the permeability of oxygen is 0.4ft
3(STP)/ft
2Psi days, exceed the undressed stationary value 0.33ft of member greatly
3(STP)/ft
2Psi days.
According to the present invention, the permeable membrane member is that the preparation of these members is not a part of the present invention with conventional method preparation.Any known preparation process comprises used encapsulation process, all may be utilized.After the member preparation was finished, their available methods of the present invention were carried out initial treatment.This comprises makes member at about 50 ℃～140 ℃, preferably is about 80 ℃～140 ℃, preferably is about about 0.5～3 hour of 100 ℃～125 ℃ following heat treated, and preferably is about 1 hour.Temperature and time otherwise cause member to damage, it can not be superheated to the polymer that makes film and/or seal and damage or damage.Therefore, Shi Yi temperature must be selected in the said temperature scope according to used specific polymer of member and used pressure.As long as know the composition of polymer, the professional promptly knows to adopt which kind of temperature and pressure that film is damaged.
Film can under atmospheric pressure or be below or above heating under the atmospheric pressure.As long as do not damage film when heat treatment, any pressure all can adopt.
Heating can be adopted any traditional mode, as in heating cabinet, has or do not have circulation, uses steam, uses hot gas, with microwave or infrared heating device, or any other suitable method.
Member is through using, and the recovery of rotten film structural component is handled on permeability and/or selectivity, and is identical with processing mode to new structural member.
For the convenience of describing, the present invention is described in any further with doughnut or polysulfone hollow fibre composite membrane especially.But should be noted that scope of the present invention is not limited in is used on the asymmetric, compound of hollow fiber or the porous molecular screen type film.Any employing all is scopes of the present invention by the permeable membrane element in the gas lock out operation of method processing of the present invention.In addition, according to the present invention, spiral, plain film formula that these permeable membranes also can be made into, or other required configuration, and described doughnut formula.Those of ordinary skill understands multiple feasible preparation method and they are in industrial possible purposes.For example, press JCabasso and APTamrakis " composite hollow fiber membrane " (Composite Hollow Fiber Membranes JAppPolymSci at " polymer applications science magazine ", 23,15091525(1979) the doughnut of disclosed method preparation in the literary composition, have continuous passage, fluid is flowed along outer and interior interlayer.Usually, the averga cross section diameter of micropore is less than 20000 dusts, at some doughnut middle section diameter less than 1000 or 5000 dusts.To good especially doughnut, especially in the gas that the material of doughnut plays a crucial role to separation separates, in the patent as above-mentioned Henis etc., average micropore diameter of section 5～200 dusts of only having an appointment.Usually total surface area is at least about 10: 1 to the ratio of the micropore sectional area of total doughnut.To gas separation membrane, especially in the gas that the material of doughnut plays a crucial role to separation separated, total surface was at least about 10 with the ratio of total doughnut micropore sectional area
3: 1, some doughnut even can reach about 10
3: 1～10
8: 1.
The wall thickness of useful is doughnut is enough, does not need with special equipment it to be handled.Usually, doughnut has about 20～1000 microns external diameter, and perhaps 50～1000 microns, as 250～1000 microns, its wall thickness is at least about 5 microns.Wall thickness can be up to about 200 or 300 microns in some doughnut.In order to obtain the required flow that passes through doughnut, particularly when the doughnut that is at least about 50 microns with wall thickness, can there be a large amount of voidages in the doughnut, the space is the zone that does not have the doughnut material in the hollow fiber walls.Therefore, when these spaces occurred, the density of doughnut was less than the density of the tight material of doughnut.Usually, the space is useful, and its volume can show 90% of volume (being the volume that overall size constitutes) up to doughnut, as 10%～80%, is 20% or 30%-70% sometimes.Except in gas feed general with dirt, another dirt source is the used lubricating oil of pump or miscellaneous equipment, it is taken on the film by gas raw material stream.
The used material of doughnut can be natural solid material or synthetic, and is organic or inorganic.The selection of doughnut material can be based on the mechanical strength of hear resistance, solvent resistance and/or doughnut, and used separation process and the shown other factors of separation condition.Therefore, the selection of doughnut material can based on this doughnut material whether the separation of convection cell have a significant impact (the doughnut material has the useful separated characteristic), and coating whether convection cell separate influential and decide.Doughnut can be flexible or belong to rigidity basically.Its used material can be inorganic matter such as hollow glass, pottery, sintering metal or analog, fiber.Using under the situation of polymer, as long as can make the porous hollow fiber shape with the method that is fit to, then addition polymers and condensation polymer all can.Generally organic matter or organic polymer and inorganic material (filler) are mixed with doughnut.Typical polymer can be to replace or unsubstituted polymer, and they can be selected from polysulfones, and polystyrene comprises containing the styrol copolymer class, as acrylonitritrile-styrene resin, and SB and styrene-ethylene base benzyl halide copolymer; Polycarbonate-based, the cellulosic polymer class, as cellulose, cellulose acetate; Cellulose acetate-butyrate, cellulose propionate, methylcellulose, nitrocellulose etc.; Polyamide-based and polyimide comprises aromatic polyamide and aryl polyimides; Polyethers, polyarylether class such as polyphenylene oxide; The polyesteramide diisocyanates; Poly-amino methyl ethyl ester class; Polyesters (comprising poly-aryl compound), as polyethylene terephthalate, poly-alkyl methacrylate, polyalkyl acrylate, polyphenylene terephthalate etc.; Multiple sulfides; The polymer class of the unsaturated 'alpha '-olefin monomers except that above-mentioned, as polyethylene, polypropylene, PB Polybutene-1, poly-(4-methylpentene-1), the polyvinyl compounds, as polyvinyl chloride, polyvinyl fluoride, polyvinylidene chloride, Kynoar, polyvinyl alcohol, polyvinyl ester class such as polyvinyl acetate and polyvinyl proprionate; Poly-phosphine piperazine class or the like.The preparation method of doughnut is general, and the professional knows.
Be deposited on divided thin film absciss layer on the porous matrix or filmogen and generally be add with the solution form in a suitable solvent or be shaped by in-situ polymerization.The technical staff knows that many such materials can get, and wherein some is selective to partially mixed thing gas, and some does not have.This is not a conclusion of the present invention, because method of the present invention is to improve the permeability that the permanent film that uses has.
The typical filmogen that is suitable for can be to replace or unsubstituted polymer, and these materials comprise synthetic rubber, natural rubber.HMW and/or high boiling liquid, organosilicon prepolymer polymers class, polysiloxanes (siloxane polymer) class, the polysilazane class, polyurethanes, poly-table chlorhydrin, the polyamine class, poly-imines class, polyamide-based, contain the acrylonitrile copolymer class as poly-(α-Lv Bingxijing) copolymer analog, polyesters (poly-lactam and poly-arylide), as polyalkyl acrylate class and poly-alkyl methacrylate class, poly-succinate class, alkyd resins class, cellulosic polymer class, polysulfones, particularly fatty family polysulfones, poly-(alkylidene) glycols such as polyethylene glycol, polypropylene glycol etc., the polymer class such as the polyolefin that get by unsaturated 'alpha '-olefin monomers, polyethylene for example, polypropylene, polybutadiene, poly-(2, the 3-dichloroprene), neoprene, polystyrene comprises polystyrene copolymer, as SB, polyvinyl compounds such as polyvinyl alcohol, Pioloform, polyvinyl acetal (as polyvinyl formal and polyvinyl butyral resin), polyethylene ketone (as poly-ethylene methacrylic ketone), polyvinyl ester, (as the polyethylene benzoic ether, polyethylene halogen, poly-acetylenedihalide, the ethylene fluoride copolymer, the polyarylether class, as poly-inferior dimethyl phenylate, polycarbonate-based or the like and any copolymer that comprises the block copolymer that contains above-mentioned repeating part, and contain above-mentioned graft and blend, and the monomer of any above-mentioned polymer.The solvent that is fit to comprises liquid alkane, as pentane, cyclohexane etc., and aliphatic alcohol such as methyl alcohol, some halogenated alkane and halo dialkyl ether, and dialkyl ether or the like, the mixture that also comprises.
As previously mentioned, filmogen is coated to the porous matrix surface from solution.This is layed onto in the solution by making the porous matrix surface pass or soak usually, should be appreciated that porous matrix can be dry, or uses the liquid compatible with the solvent that is used for being prepared into coating solution wetting in advance.Any solvent or solvent mixture to filmogen all can adopt, and this also is that the professional knows, and they know which solvent is suitable for specific filmogen.Solvent can be dissolved into membrane substance, and they can be inorganic or organic matter, can obtain homogeneous phase or uniform solution.Can remove by evaporation drying or liquid bath then and desolvate, also can select for use in addition in the solvent also can a kind of coagulating agent to filmogen.
A kind of way that realizes the inventive method is represented in following explanation.Clearly it is not to implement unique way of the present invention, is limitation of the present invention so can not understand.In addition, for convenience, use porous hollow fiber, they are coated with filmogen, thereby form hollow fiber composite membrane.Be coated to the film on the porous hollow fiber stromal surface, its thickness generally is about 300～7000 dusts, preferably is about 500～2000 dusts.
Hollow fiber composite membrane is made an assembly, and seal according to a conventional method with solid polymer at two ends, and the high-pressure side of assembly and low-pressure side are separated, thereby it be can be used in the gas separation.By discovery of the present invention, before being used for the gas separation, making assembly be heated to aforesaid temperature and handle.In some cases, find that this initial heating processing procedure compares with the assembly that carries out heat treated without the inventive method, increased the long-time permeability of assembly, in addition, assembly can need not method of the present invention carry out heat treated and be used for the gas separation when beginning, then, when the permeability reduction of assembly and when rotten, make rotten assembly carry out heat treated, like this, selectivity and/or permeability will return to the initial value of assembly and equate or higher value.Then, these numerical value will be stabilized in than without method of the present invention assembly being carried out the higher value of initial value at the beginning of the assembly that heat treated promptly comes into operation.
Also available then method of the present invention continues to handle to assembly, no matter whether assembly carries out initial heating handles, and it can repeat repeatedly, and till this processing method was inoperative to hollow fiber composite membrane, it depended on certain products.
The selectivity of film used herein or film device or title separation, be interpreted as its expression: the easy infiltration component of mixture to be separated is to the ratio of difficult infiltration component infiltration rate, and mean permeability is expressed as cubic feet (normal temperature-pressure)/square feet Pascal sky.
Large quantities of polysulfone hollow fibre matrix used in the specific embodiment of the present invention can be according to the prior art for preparing of knowing.Doughnut generally is spinning from the serosity combination of required fibre-forming polymer, poly-cold, washing and make.Be entitled as " composite hollow fiber membrane " (Composite Hollow Fiber Membranes according to people such as Cabasso at " polymer applications science magazine " book, Journal of Applied Polymer Science Vol.23,1509～1525(1979)) described in the literary composition, polysulfone hollow fibre is formed by polysulfones, polyvinylpyrrolidone and dimethylacetylamide three component solution spinning, the polymer total concentration is preferably 40～52%(weight in the solution), the ratio of polysulfones/polyvinylpyrrolidone is 1.5～2.0.Known pipe one pipe inspection technology is used in the spinning step, and 21 ℃ water is as the quenching medium of fiber in the outer tube.The quenching medium of fibrillar center is an air.Fiber is washed under about 50 ℃～60 ℃,, be coated with stain again and form the required composite membrane of membrane material subsequently with the doughnut drying.For reaching this purpose, ps hollow fiber uf membrane is passed through a hot-air drying tower drying down at 30 ℃.Dried doughnut applies equably with ECN7NF solution immediately.The preparation of ethyl cellulose solution is that 1% ethyl cellulose is dissolved in the isopropyl alcohol, filters with 1.5 millimicrons of glass filters, it is coated with steeps on the polysulfones again.Make dry doughnut by the coating solution in the container for paint, with it around to dry in an air-oven before the knot device.The polysulfone hollow fibre composite membrane that obtains has an ethyl cellulose material coating, and thickness is about 0.2 micron.
Used film structural component in following experiment and embodiment is that end with the fibril of a branch of about 8 inches long composite membranes is encapsulated in the epoxy section of jurisdiction and constitutes, and its high-pressure side and low-pressure side are separated.In each operation, all use non-same member and under engaging in speculation and profiteering, carry out the side examination near zero point.Each member has about 0.5 square feet of film surface area.
The comparative example I
Carry out one group of air separation with four members as method for preparing.Each member carries out the air separation test with the undressed air stream that contains about 5～10ppm oil vapour under 100 Pascals, 25 ℃.The average primary oxygen permeability of four members is 0.4ft
3(STP)/ft
2Psi days, average O
2/ N
2Selectivity is about 4.After continued operation in 300 hours, oxygen permeability is reduced to 0.3ft
3(STP)/ft
2Psi days.Selectivity does not change.Handled about 2000 hours continuously, these numerical value do not change again.800 hours operation of beginning is represented with curve C in the accompanying drawing.This is as embodiment 1,2,3,6 and 7 comparative example.
The following examples are used for further specifying the present invention.Operate under time of indication and arbitrarily stop.
Embodiment 1
With the member of an aforesaid method preparation, flow to the separation of line space gas at 100Psi, 25 ℃ of following undressed air that contain about 5～10ppm oil vapour of using.In the starting stage that gas separates, the initial permeability of oxygen is about 0.39ft
3(STP)/ft
2Psi days, O
2/ N
2Selectivity is 4.Operate after 400 hours, oxygen permeability is about 0.32ft
3(STP)/ft
2Psi days.In this stage, shift out member, be placed in the cross-ventilation baking oven and heated 1 hour down in 120 ℃, cool to room temperature is proceeded air separation again, and one recovers to separate, and the permeability of oxygen is elevated to unexpected 0.54ft dramatically
3(STP)/ft
2Psi days.This shows that it has improved approximately 40% than the initial permeability of oxygen, improves about 70% than the permeability of handling with the inventive method before the member.This permeability descended in 75 hours gradually, and 900 hour operating time intrinsic permeability afterwards is stabilized in about 0.38～0.4ft
3(STP)/ft
2Psi days.Again assembly is heated down in 120 ℃ in an identical manner, cools off, and then carry out air separation.After the one recovery air separation, oxygen permeability is elevated to about 0.53ft once more
3(STP)/ft
2Psi days.It drops to about 0.39ft gradually in subsequently 2100 hours
3(STP)/ft
2Psi days.These data show with method of the present invention can obtain unexpected effect, also can not add to repeat to strengthen with limiting.800 hours operating conditions of beginning is shown in the curve A of accompanying drawing.
Embodiment 2
A member that makes as stated above, in a cross-ventilation baking oven, in 120 ℃ of down heating 1 hour, cool to room temperature again at 100Psi, under 25 ℃, flows to line space gas separation test with the undressed air that contains about 5～10ppm oil vapour.The primary oxygen permeability is 0.52ft
3(STP)/ft
2Psi days, O
2/ N
2Selectivity is 3.8.Through about 575 hours, oxygen permeability dropped to about 0.4ft gradually
3(STP)/ft
2Psi days.Remain on this value then and reach 800 hours again.The curve B of accompanying drawing is represented this embodiment.
The member that is noted that embodiment 1 is after recovering to handle through heating, and its oxygen permeability is stabilized in the slightly high numerical value of the initial permeability of ratio.The member of embodiment 2 then begins with a higher primary oxygen permeability, reduces gradually then, the member that is stabilized in embodiment 1 at last after heating recovers to handle on the stable numerical value.The data of these two examples show that the time of heat treated does not show important, and it can carry out when beginning, or are carrying out after operating after a while.It also shows, carries out heat treated by method of the present invention in separation process, and its permeability will remain on its initial value, even higher than initial value.Yet its rate of gushing of the member in the comparative example is stabilized in a numerical value lower than primary oxygen permeability, and is significantly less than embodiment 1 and 2 stationary values that reached.As mentioned above, the data that obtain in this comparative example also are used for making accompanying drawing.
Embodiment 3
Prepare a permeable membrane member by above-mentioned conventional method, this member heated 1 hour down in 120 ℃ in a compression chamber, compression chamber's compressed air, and feed side pressure is 100 Pascals, open side pressure 0.Cool to room temperature under atmospheric conditions then.In heating process, this assembly carries out the air separation test with embodiment 1 described method.The primary oxygen permeability is 0.47ft
3(STP)/ft
2Psi days, the selection coefficient of oxygen and nitrogen was 3.7, and after continued operation in 800 hours, it is stable that permeance property keeps, and at this moment, the oxygen permeability of member is 0.39ft
3(STP)/ft
2Psi days, selecting coefficient was 4.These data show in the method for the invention, and the hot gas of compression can be used for handling film.
Embodiment 4
The member that makes as stated above with the undressed air stream that contains about 5～10ppm oil vapour, at about 20 ℃, under the 100Psi condition, carries out the air separation test.The initial permeability of oxygen is 0.48ft
3(STP)/ft
2Psi days, O
2/ N
2Selectivity is about 4, operates after 336 hours, and oxygen permeability drops to 0.41ft
2(STP)/ft
2Psi days.Selectivity there is not change substantially.At this moment, member was heated 1 hour with steam (100 ℃ in atmospheric pressure), make its cool to room temperature again.After air separation was recovered, oxygen permeability was elevated to 0.67ft
3(STP)/ft
2Psi days, selectivity was 3.8, and after 512 hours air separation subsequently, oxygen permeability is 0.64ft
3(STP)/ft
2Psi days.Selectivity is 3.9.
These data show wet heating source such as steam, and with dried heating source such as hot-air, or the convection oven heating is equally effective in the present invention.
Embodiment 5
With existing method (United States Patent (USP) 4,207,192 and United States Patent (USP) 4,631,128), and with the composite hollow fiber membrane that above-mentioned described method makes, prepare a gas separating member, its length is 26 inches, and diameter is 5 inches.This member carries out the laboratory test of air separation at 23 ℃ of compressed air of using about 100Psi down, carries out some hrs, and the permeability of oxygen is 0.57ft
3(STP)/ft
2Psi days.O
2/ N
2Selectivity is 4, deposit about 5 weeks after, more under the same conditions to component test 3 hours, this moment, its oxygen permeability was 0.51ft
3(STP)/ft
2Psi days, selectivity was identical, after the week, carried out pilot scale at Yi Xiaochang, continued 6 months intermittently.During this period, air separation has been carried out 2100 hours, and then, the mensuration permeability is 0.38ft
3(STP)/ft
2Psi.Selectivity is 4.Member shifts out from the pilot plant device, is heated to 100 ℃, keeps 2 hours under this temperature, adopts under atmospheric pressure, passes member as heating means by hot air circulate.Air at room temperature replacement with 100Psi adds hot-air, and member was cooled off in 1 hour, and the permeability of recovering the back member is 0.51ft
3(STP)/ft
2Psi days.O
2/ N
2Selectivity be 4.These numerical value remain unchanged in operations in 450 hours subsequently.These data clearly illustrate that by the inventive method and improve the afterclap that permeability reached.
Embodiment 6
A member that is made by said method at 100psi, carries out air separation test under 25 ℃ with the undressed air stream that contains 5～10ppm oil vapour, and in the starting stage that gas separates, the primary oxygen permeability is 0.4ft
3(STP)/ft
2Psi days.O
2/ N
2Selectivity be 3.8.After operation in 377 o'clock, permeability is 0.30ft
3(STP)/ft
2Psi days.Selectivity is 4.In 80 ℃ of heating 1 hour, cool to room temperature was proceeded air separation to member again in a convection current baking oven.At this moment, oxygen permeability is brought up to 0.41ft
3(STP)/ft
2Psi days.In operations in about 930 hours subsequently, oxygen permeability is 0.3ft
2(STP)/ft
2Psi days.Selectivity is 4.Member again in a convection current baking oven in 120 ℃ of heating one hour, cool to room temperature again continues air separation.After this heat treated, oxygen permeability is brought up to 0.44ft
3(STP)/ft
2Psi days, selectivity was 3.7, and through after the operation in 2000 hours, oxygen permeability is 0.32ft again
3(STP)/ft
2Psi days.Selectivity 4.This embodiment shows can be suitable for very wide temperature range, and can carry out the repetition heat treated to same member, so that stalling characteristic is recovered.
Embodiment 7
A member that makes as stated above at 100Psi, carries out air separation test under 25 ℃ with the undressed air stream that contains 5～10ppm oil vapour.In the starting stage that gas separates, the initial permeability of oxygen is 0.41ft
3(STP)/ft
2Psi days, O
2/ N
2Selectivity be about 4.After operation in 400 hours, oxygen permeability is 0.31ft
3(STP)/ft
2Psi days.In 120 ℃ of heating 1 hour, cool to room temperature continued air separation to this member again in a convection current baking oven.At this moment, the permeability of oxygen is 0.52ft
3(STP)/ft
2Psi days, selectivity was 3.8.
Claims (9)
1, a kind of infiltrative method that is used for improving the gas separation membrane that gas separates, it is characterized in that making the permeable membrane of in use having degraded under about 50 ℃-140 ℃ temperature, to carry out heat treated, should be about 0.5 to 3 hour heat time heating time, reaching is enough to improve permeability.
2,, it is characterized in that temperature is about 80 ℃-140 ℃ according to the method for claim 1.
3,, it is characterized in that temperature is about 100 ℃-125 ℃ according to the method for claim 1.
4,, it is characterized in that described permeable membrane is a composite hollow fiber membrane according to the method for claim 2.
5,, it is characterized in that described composite hollow fiber membrane is to constitute by apply one deck filmogen on a porous hollow fiber matrix according to the method for claim 4.
6,, it is characterized in that the porous hollow fiber matrix of described permeable membrane is polysulfones according to the method for claim 5.
7, according to the method for claim 5, the filmogen that it is characterized in that described permeable membrane is an ethyl cellulose.
8,, it is characterized in that heat treated carries out being lower than under the atmospheric pressure according to the method for claim 1.
9,, it is characterized in that described heat treated carries out being higher than under the atmospheric pressure according to the method for claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88108819 CN1024324C (en) | 1987-11-02 | 1988-11-02 | Treatment of permeable membranes |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/115,927 US4877421A (en) | 1987-11-02 | 1987-11-02 | Treatment of permeable membranes |
| CN 88108819 CN1024324C (en) | 1987-11-02 | 1988-11-02 | Treatment of permeable membranes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1042314A CN1042314A (en) | 1990-05-23 |
| CN1024324C true CN1024324C (en) | 1994-04-27 |
Family
ID=25742524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88108819 Expired - Fee Related CN1024324C (en) | 1987-11-02 | 1988-11-02 | Treatment of permeable membranes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1024324C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105457501B (en) * | 2015-12-19 | 2018-01-05 | 杭州水处理技术研究开发中心有限公司 | A kind of preparation method of efficient gas seperation film |
-
1988
- 1988-11-02 CN CN 88108819 patent/CN1024324C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1042314A (en) | 1990-05-23 |
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