Installation and method for producing a fiber from a polymer solution

Abstract

The invention relates to an installation for producing a fiber, in particular a spun fiber, from at least one polymer solution, comprising a control and regulating unit, a supply and feed unit for media, a feed unit for media, and a spinning unit for forming the fiber. At least the following installation units are provided, in the specified sequence, downstream of the spinning unit in order to treat the fiber: a. a solvent-exchange unit, into which or through which the fiber can be introduced or passed immediately after the spinning unit, and b. at least one post-treatment unit, comprising a thermal treatment unit having at least one thermal treatment station. At least one thermal treatment station of the thermal treatment unit is provided downstream of the exchange unit, said thermal treatment station being a temperature-control station and comprising an IR emitter, and the fiber can be at least temporarily received in and / or guided through the temperature-control station. The invention further relates to a production method having a temperature-control step using an IR emitter.

Description

[0001] Plant and method for producing a fiber from a polymer solution

[0002] The invention relates to a plant and a method for producing hollow fiber membranes for fluid separation, in particular for gas separation.

[0003] Manufacturing processes for membrane materials for fluid separation are known in the prior art, with such membrane materials based on polyimides being described, for example, in WO 2014 / 202324 A1 or WO 2011 / 009919. Such membrane materials, as integrally skinned asymmetric membranes (ISA membranes), have an active (separation) layer (separation layer) of 10 to 200 nm. It is generally known that polyimides represent a class of polymer materials that enable gas separation of a fluid mixture with a high permeance of one of the fluids and / or with high selectivity. Polyimides are also characterized by very good mechanical, chemical, and thermal resistance in gas separation applications.

[0004] It is known that polyimides and other glassy polymers used as membrane materials for gas separation exhibit a decrease in their initial separation performance, for example due to plasticization (softening) (“Quantification of sorption, diffusion, and plasticization properties of cellulose triacetate films under mixed-gas CO2 / CH4 environment” Genduso et al; J. of Membrane Science, Volume 610, 01.09.2020, Article number 118269), due to physical aging (“Physical aging of thin glassy polymer films monitored by gas permeability” Huang Y. et al; Polymer, Vol. 45, Issue 25, Pages 8377 - 8393, November 2004) and / or due to contact with impurities in the feed stream (“Properties of a polyimide gas separation membrane in natural gas streams”; White et al; J. of Membrane Science, Volume 103, Issue 1-2, Pages 73 - 82, July 14, 1995).

[0005] The aforementioned disadvantages can be partially or even completely avoided if the hollow fiber membrane is heated above 300 °C, as described, for example, in WO 2011 / 009919 A1 and US 9,873,093 B2. Furthermore, it is proposed to provide a defined heating gradient during annealing to achieve defined, high permeances and selectivity. This gradient, for example, as described in WO 2011 / 009919 A1, comprises three stages in a circulating air drying cabinet (convection oven), namely at 70 °C (0.5 h), 150 °C (2 h), and 250 °C (12 h).

[0006] For further improvement, WO 2014 / 202324 A1 proposes drying hollow fibers, preferably at a temperature in the range of 50 to 100 °C, and then annealing them. The drying process should remove, for example, water, isopropanol, or hexane, so that the total water and / or residual solvent content is in the range of 0 to 5 wt.%. This is because an excessively high residual water and solvent content during the annealing of entire membrane bundles leads to the membranes sticking together. Furthermore, excess water can lead to hydrolysis and thus chain breakage and a mechanically unstable membrane. According to WO 2014 / 202324 A1, it is advantageous if the maximum water content before the start of annealing is below 5 wt.%, even if any water content would evaporate during the annealing itself.

[0007] It is proposed to provide a drying unit and a tempering unit, wherein the tempering must be carried out at a temperature in the preferred range of 140 to 180 °C under vacuum in the range of 0.6 to 0.9 bar and under an inert gas atmosphere, wherein a very long tempering time of preferably 10 to 16 hours is required.

[0008] The disadvantage of these previously known and fundamentally proven processes and systems is that a relatively complex system design is required and very long treatment times for the fibers are necessary.

[0009] The object of this invention is therefore to provide a plant and a process for a fluid separation membrane which has a higher production capacity than known plants and processes, while maintaining or increasing product quality in terms of permeability and / or selectivity.

[0010] This object is achieved according to the invention with a system for producing a hollow fiber, wherein the hollow fiber is formed from at least one polymer solution. The system comprises a control and regulation unit, a storage and feed unit for media, and a spinning unit for forming the fiber. Downstream of the spinning unit, at least the following system units are included in the stated sequence for treating the fiber: a. an exchange unit for solvent exchange, which can in particular comprise a (first) fixing unit or can essentially be formed therefrom, into which the fiber can be fed or passed through immediately after the spinning unit, and wherein a washing unit can advantageously be included downstream of the fixing unit, b.at least one post-treatment unit, comprising a thermal treatment unit with at least one thermal treatment station, wherein downstream of the exchange unit at least one thermal treatment station of the thermal treatment unit is provided, which is designed as a tempering station, comprising at least one tempering furnace, wherein the at least one tempering furnace comprises at least one infrared emitter (IR emitter), wherein the fiber can be at least temporarily received in and / or passed through the at least one tempering furnace.In this case, the tempering furnace is designed and adjustable in such a way that the at least temporarily received and / or passable fiber and wherein the tempering furnace is designed to heat the at least temporarily received and / or passable fiber for a defined time (tempering time) up to a temperature which is below the glass softening temperature (TG), in particular and also i) in the range up to 80 °C below the glass softening temperature (TG), and / or ii) in the range of greater than 250 °C.

[0011] In an advantageous embodiment, the tempering furnace is designed and adjustable to heat the at least temporarily received and / or passable fiber i) for a defined time (tempering time) up to a limit temperature which is max. 1 °C to 4 °C below the glass softening temperature (TG), in particular to a limit temperature in the range from 70 °C to 1 °C below the glass softening temperature, preferably in the range from 65 °C to 1 °C and / or ii) to heat the fiber to a temperature of greater than 250 °C to 450 °C, preferably 280 °C to 450 °C.

[0012] In this case, it is particularly advantageous if the system is designed to always maintain a distance of 1 °C to 4 °C from the glass softening temperature (TG) with regard to the at least temporarily accommodated and / or passable fiber, in order not to damage the structure, in particular the desired porosity, of the hollow fiber. To avoid damage to the fiber due to fluctuations in the heating temperature, it may be preferable if the system is designed such that, instead of the aforementioned 1 °C distance from the TG, a distance of 1.5 °C, 2 °C, 2.5 °C, 3 °C, or 3.5 °C can be provided.

[0013] In this case, “max. 1 °C, in particular max. 4 °C” means that it is particularly advantageous if the distance of at least 1 °C, preferably 4 °C, from the respective glass softening temperature (TG) of the fiber material (polymer substrate) is maintained in order not to damage the structure, in particular the desired porosity, of the hollow fiber.

[0014] In order to set defined material states of the fiber and to improve the controllability of the tempering, according to an advantageous embodiment of the system it can be provided that at least one further thermal treatment unit is arranged, comprising a drying station upstream of the tempering station.

[0015] The fiber is thus annealed in the annealing station or annealing furnace directly or indirectly by the IR radiation of at least one IR emitter. "Indirectly" means that the IR radiation can reach an individual fiber through neighboring individual fibers and / or via reflectors.

[0016] Here, "annealing" means heating the fiber for a defined time (annealing time) to a limit temperature that is max. 1 °C to 4 °C below the glass softening temperature (TG), in particular in the limit temperature range of 80 °C to 1 °C below the glass softening temperature, preferably in the range of 70 °C to 1 °C, and particularly preferably in the range of 65 °C to 4 °C below the glass softening temperature. The glass softening temperature TG can be determined using various dynamic differential calorimetry (DSC), also called differential scanning calorimetry (DSC), in particular according to the method of DIN 53765.

[0017] Analogously, the decomposition temperature (Tz) of a fiber and / or fiber material (polymer substrate) can also serve as the upper limit temperature and limit temperature range, depending on which effect—decomposition or glass softening—occurs first when the fiber and / or fiber material (polymer substrate) is heated. Decomposition can, for example, consist of burning, incineration, cracking, embrittlement, or other destructive effects.

[0018] In the case of a fiber material with a material property of Tz < TG, where the degeneration is characterized by the fact that increased material shrinkage already sets in at Tz < TG, especially Tz « TG, the limit temperature should be lower than Tz. Thus, the system should advantageously be designed to always maintain the distance to Tz in a manner analogous to the limit temperature with respect to the at least temporarily absorbed and / or passable fiber, in order to avoid negatively affecting, in particular, the fiber dimensions (macrostructure) and / or the pore structure (microstructure) of the fiber.

[0019] Fiber materials exhibiting pronounced degradation at temperatures below and above Tz include PIM-1 polymers with high intrinsic microporosity. An example of a PIM is the polycondensation product of 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,T-spirobisindane (CAS No. 77-08-7) and 1,4-dicyanotetrafluorobenzene (CAS No. 1835-49-0).

[0020] This degradation temperature Tz can be determined by thermographic analysis in a nitrogen atmosphere (Konnertz, N. et al, Molecular mobility of the high performance membrane polymer PIM-1 as investigated by dielectric spectroscopy, ACS Macro Lett. 2016, 5, 528-532).

[0021] In this way, a temperature of more than 250 °C, in particular more than 280 °C, is achieved in the tempering oven by means of the IR radiators for the polymer materials in question, whereby the aforementioned material-dependent distance is maintained.

[0022] The thermal treatment unit according to the invention can thus comprise a single thermal treatment station for carrying out a single drying step, which is designed as a tempering station with a tempering furnace and the at least one IR emitter and by means of which the tempering of the fiber or the polymer material takes place. In this embodiment with a single thermal treatment station, strictly speaking, a combined drying and tempering step takes place. However, it has been shown that the high energy input in the tempering furnace onto an externally wet or very moist fiber leads to adverse impairments of the fiber during tempering. Thus, the thermal treatment unit can advantageously additionally comprise at least one further thermal treatment station for carrying out at least one further drying step, arranged upstream of the tempering station, in particular directly upstream of the tempering furnace.Due to the high temperatures applied, tempering in the tempering station always also represents an independent drying step for the fiber.

[0023] The additional thermal treatment station can advantageously comprise, or be connected to, a drying agent that is an alternative to IR radiation and a heating device that is an alternative to an IR radiator. In particular, a drying station for a standalone drying step can be provided downstream of the exchange station for discharging the solvent from the exchange station, in particular upstream of a coating station, for producing defined surface properties of the fiber upon introduction into the coating station. Furthermore, at least one further drying station for a further drying step can advantageously be provided downstream of a coating station, in particular for separating the solvent contained in the coating station or the coating agent used there.Even if "a thermal treatment unit" is mentioned here, this does not generally represent a structural unit; rather, it serves to linguistically bundle all thermal treatment stations or steps, i.e. different drying stations and execution of the respective drying steps. It is particularly advantageous if a drying station is provided immediately upstream of the tempering station, which can be identical to one of the aforementioned, in order to establish a defined state with regard to the moisture content of the fiber at the entrance to the tempering station and thus to enable the shortest possible duration, in particular for the high-energy tempering.

[0024] In this context, the "tempering station" is understood to mean, in particular, the central tempering furnace and all directly associated supply and disposal devices, such as, in particular, the gas supply line, gas discharge line, sensors, possibly the power control unit, the cooling unit with the necessary connections, etc. The "tempering furnace" comprises at least one IR emitter and can accommodate at least one individual fiber inside in order to heat it, at least temporarily, to a temperature below the glass softening temperature TG or the degeneration temperature Tz using IR radiation, as described herein. Even if the tempering station is not identical to the tempering furnace, in some cases no distinction is made between tempering station and tempering furnace below, whereby the context of the text reveals the intended meaning. For example, a formulation that "the tempering station comprises an IR emitter" is to be understood to mean that "the IR emitter is included in the tempering station as part of the tempering furnace."

[0025] Although the term "IR emitter" is primarily used below, this refers not only to the actual infrared radiation source (IR radiation source), but also to an IR unit comprising one or more IR emitters. A continuously operating system and a corresponding continuous process have been found that make it possible to reduce the annealing times known from the prior art by a factor of approximately 0.001 or more, using, for example, an electronic, batch-operated convection oven. Furthermore, lengthy heating steps can be completely avoided.

[0026] In this context, "polymer solution" refers not only to the substances mentioned herein as examples, but also to liquid and / or liquefied polymer melts. "Polymer solution" refers in particular to liquid and / or liquefied polymers, which are contained in a solvent or solvent mixture.

[0027] In the present context, "polymer solution" refers not only to the substances mentioned herein as examples, but also to liquid and / or liquefied polymer melts. "Polymer solution" refers in particular to liquid and / or liquefied polymers, which are contained in particular in a solvent or solvent mixture. The polymer solutions include: aromatic polyimides, aromatic polyetherimides, aromatic polyamides, polyarylene ethers, aromatic polybenzimidazoles and / or mixtures thereof; polysulfones and / or mixtures containing polysulfones;

[0028] Solutions of polymers exhibiting intrinsic microporosity (PIMs); generally, solutions of polymers suitable for the production of membranes for gas separation, in particular for the production of (spun) hollow fiber membranes; cellulose-based solutions suitable for the production of membranes for gas separation.

[0029] The polymer solution may further comprise 2D or 3D fillers that are suitable in terms of size and composition for spinning using the hollow fiber spinning unit. These fillers can advantageously be, for example, zeolites, MOF particles (metal-organic framework materials), mexenes (MXenes), and / or graphenes. Furthermore, hollow fiber membranes are intended to be included in which the active separation layer is formed at least partially from a 2D or 3D filler, such as zeolites, MOF particles (metal-organic framework materials), mexenes (MXenes), and / or graphenes.

[0030] Particularly when fillers are present in the polymer solution, it is advantageous to anneal individual fibers or smaller (partial) fiber bundles of up to a maximum of 180 individual fibers, ideally up to a maximum of 120 individual fibers, and ideally up to a maximum of 60 individual fibers per (partial) fiber bundle. Without being limited to one interpretation, fillers can lead to a greatly increased extinction and / or reflection of energy, especially IR radiation, thus reducing the homogeneity of the annealing of the individual fibers in the fiber bundle.

[0031] In the system, the fibers are preferably conveyed in strands and uncut, with the drive via conveyor rollers and / or at least one traction device in the main conveying direction. The main conveying direction represents the overriding direction of movement in the x-direction. Advantageously, the fibers are deflected multiple times along sections, deviating from the main conveying direction in the x-direction, particularly in the z-direction, for example, in the washing unit, the thermal treatment unit, etc., to allow for the required residence time in each unit.

[0032] The individual fibers, which are at least initially spaced apart from one another, are kept at a distance by comb-like or finger-like forming elements of forming units; usually the individual fibers are arranged next to one another in a line, ie spaced apart from one another in the y-direction.

[0033] In this context, "fibers" refers to the group of individual fibers, regardless of the plant location or the treatment type, unit, and / or station, whereby the plant location and treatment type, unit, and / or location are determined from the context. In particular, "fiber(s)" primarily refers to the uncut (individual) fiber(s) or fiber strand. The terms "fiber" and "individual fiber" are sometimes used synonymously.

[0034] The term "bundle," "sub-bundle," or "fiber (sub-)bundle" refers here to an arrangement of a plurality of individual fibers in which the individual fibers are arranged in contact with one another and, for example, substantially parallel to one another or twisted against one another around a common longitudinal axis. A "bundle," "sub-bundle," or "fiber (sub-)bundle," hereinafter referred to as "bundle," can be held and / or formed by a guiding and / or gripping tool, possibly only temporarily formed, unless expressly stated otherwise.

[0035] Furthermore, a “bundle” can be fixed and formed against each other at least temporarily on one or two sides by a fixing element, such as a banderol, a lacing, a clamp.

[0036] The "main conveying direction" is determined by the sequence of the systems' treatment units and stations, with the fibers themselves being redirected as needed by means of guide elements. Thus, the path-dependent thread travel direction along the fiber's longitudinal axis may differ from the (overarching) main conveying direction. In this case, the respective local "transport direction" within the system is considered to be parallel to the alignment of the "fiber's longitudinal axis," whereby local lateral shifts to change the (transverse) distances between fibers may be included.

[0037] Advantageously, the system comprises a plurality of guide and drive elements along the conveying path of the thread, which may be, for example, guide fingers, guide rollers, guide plates or other suitable elements, whereby the guide and drive elements may be located inside and outside the treatment unit, even inside liquids or a liquid volume. The media contained in the media supply and feed unit may be

[0038] - include fibre media, namely media and materials from which the fibre itself is formed at least temporarily, and

[0039] - Process media required for other treatments of the fiber and / or system components. These can include, for example, the core fluid for forming the hollow fiber, fixation media for the raw fiber, washing fluids such as water, alcohols, air, gases (N2), etc., or other consumable media.

[0040] The spinning unit advantageously comprises a plurality of spinning heads, wherein the spinning heads are designed in a generally known manner and are connected to the corresponding supply lines for media in order to form hollow fibers and to release them into a fixing unit or a fixing medium.

[0041] The control and regulation unit can be designed as a single or multi-part unit and is configured to operate the system at least partially automatically. Changing operating parameters and / or displaying system-relevant information can be done via a central cockpit and / or decentralized input devices.

[0042] Although treatment units such as "spinning unit," "fixing unit," "washing unit," etc., are referred to only in the singular, they can also be constructed in multiple parts or occur multiple times along the main conveyor line. For example, the generally known washing unit can consist of two or more washing stations or sinks filled with identical or different (washing) media and / or whose (washing) media have different physical properties, such as temperature, flow rate, flow direction, etc. The washing liquids are advantageously water-based and / or organic washing liquids.

[0043] Apart from the tempering device and the tempering step, with regard to the plant details and process details, reference is expressly made to WO 2014 / 202324 A1, the content of which is expressly incorporated into this application as an exemplary embodiment of the plant and process, insofar as a hollow fiber is produced from a polymer solution. This applies, for example, to the media used as well as the treatment units and their identical or analogous structure, such as the spinning unit, fixing unit (referred to therein as a "precipitation bath"), washing unit, and / or thermal treatment unit. The fixing unit is referred to in WO 2014 / 202324 A1 as a "precipitation bath," in which a solvent exchange takes place.The exchange occurs, for example, from an aprotic dipolar solvent of the polymer solution, such as dimethylformamide (DMF) and / or N-methyl-2-pyrrolidone (NMP), with a non-solvent for the polymer material, such as water. In at least one subsequent washing unit, the non-solvent is then removed using, for example, an organic solvent or mixture, such as isopropanol and / or hexane. This also applies, for example, to the fiber medium as feed for the spinning step, which is referred to as "casting solution" in WO 2014 / 202324 A1.

[0044] The post-treatment unit comprises the thermal treatment unit and thus also the tempering station, and can also comprise a washing unit upstream of the thermal treatment unit. Furthermore, the post-treatment unit can comprise at least one coating station, in particular a coating station in which a polymer material, such as polydimethylsiloxane (PDMS), is applied to the fiber as a coating agent. The application can be carried out using a bath or a spray device.

[0045] In an advantageous embodiment of the system, it can be provided that the thermal treatment unit comprises, as a thermal treatment station, in particular as a further thermal treatment station, a drying station through which the individual fibers are passed, wherein the drying station

[0046] - at least one drying element and / or

[0047] - comprises an inlet and outlet line for a drying medium, such as, in particular, a heated gas, and whereby the interior of the drying station is heated to a temperature of at least above 30 °C, advantageously above 40 °C, and ideally above 50 °C, whereby material-dependent limits for explosion protection must be observed. It is also advantageous if the interior can be heated to a maximum of 200 °C.

[0048] In the present context, “drying station” and any “thermal treatment station” that is not described as “tempering station”, “tempering furnace”, “for tempering” or similar means a station in which no tempering of the fiber takes place or can take place, and thus the fiber is heated or can only be heated well below the glass softening temperature due to its design and / or during normal operation.

[0049] The fibers are preferably dried at a temperature in the range between 50 and 100 °C, whereby the washing medium, in particular ethanol, isopropanol, butanol, heptane and hexane, is removed.

[0050] The drying station is ideally designed so that the total moisture content after drying is between 0 and 5 wt.%, preferably <3 wt.%, and especially preferably between 0.1 and 3 wt.%. The moisture content is formed essentially or exclusively from the proportions of water and the respective solvent.

[0051] Advantageously, the fibers are guided on the strand, ie uncut, through this treatment station and fed downstream, in particular immediately downstream of the tempering station.

[0052] In a further advantageous embodiment of the system, it can be provided that the thermal treatment unit comprises, as a thermal treatment station, in particular as a further treatment station, a dehumidification station through which the individual fibers are passed at a distance from one another transversely to the axial direction (longitudinal fiber axis (AF)), in particular as a strand and uncut, which station comprises at least one nozzle element which is directed onto the path of at least one individual fiber or fibers and by means of which a gas jet can be directed onto at least one individual fiber, in particular a group of individual fibers. Advantageously, all individual fibers are dehumidified by means of such nozzle elements. In this station, dehumidification essentially consists in adhering, external liquid being fluid-dynamically removed from the respective fiber by a gas pulse.In one embodiment, the nozzle element can be a gas nozzle and / or a group of gas nozzles designed as a gap nozzle.

[0053] In a further advantageous embodiment of the system, it can be provided that i) a grouping station with a grouping unit is arranged upstream of the tempering station, ii) the tempering station is arranged within a grouping unit, and / or iii) between two grouping stations of a grouping unit, wherein at least one grouping means is provided in the grouping station and / or in the grouping unit, by means of which at least one group of n individual fibers can be combined to form a bundle in mutual contact, where n is an integer value from 2 to 180, preferably from 20 to 150, ideally from 30 to 120. Groups of individual fibers are also possible in which n is > 180, in particular n to 600.

[0054] It has surprisingly been found that advantageously bundles of up to n = 180 individual fibers, preferably up to n = 120, ideally up to n = 80 can be simultaneously annealed by means of the continuously operating annealing furnace and the included IR emitters.

[0055] In an advantageous embodiment, it can be provided that the (final) bundle is formed in at least two steps, for example in a first step in a grouping station using grouping means to form two or more sub-bundles from the total number of conveyed individual fibers, and downstream in a grouping station the (final) bundle is formed with the total number of individual fibers. Advantageously, the annealing station with the IR emitter(s) of the annealing furnace is arranged between the first grouping station and the (last) grouping station for forming the (final) bundle. With very large bundles, this can have the advantage that a more uniform and, in particular, faster annealing of all individual fibers can take place. By treating the two or more sub-bundles in parallel in the annealing station or annealing furnace, the latter can be designed to be smaller in size.In a further advantageous embodiment of the system, it can be provided that the tempering station and / or the tempering furnace comprises a ventilation unit and / or is connected to or connected to a ventilation unit and / or the tempering furnace has at least one gas inlet opening, in particular a gas inlet opening for atmospheric air.

[0056] In this way, gas can be supplied and / or discharged. Furthermore, escaping vapors can be selectively diverted, and supplied gases, such as air and / or inert gases, e.g., N2 or CO2, can be suitably pretreated and conditioned. The ventilation unit can thus comprise or be connected to a gas conditioning unit. The gas conditioning unit advantageously includes any treatment elements for achieving favorable gas quality, such as (HEPA) filters, dehumidifiers, and / or temperature control units. A "ventilation unit" refers to any driven gas flow that is not exclusively driven by thermal factors.The ventilation unit is advantageously connected to the tempering station and / or the thermal treatment unit via a supply line and / or a discharge line, wherein the discharge line can be connected to a gas cleaning unit, such as a gas scrubber and / or a filter, in particular an activated carbon filter, in order to separate harmful gas components and / or to make them available for disposal.

[0057] Surprisingly, it has been found that the gas atmosphere in the annealing furnace has almost no influence on the quality of the fiber, especially on selectivity and permeance. Without wishing to commit to a specific interpretation, it is assumed that due to the very short annealing times, the oxidative influence of oxygen is very limited, thus allowing the annealing furnace to be open to the atmosphere.

[0058] In an advantageous embodiment, it can be provided that i) the tempering chamber of the tempering furnace is open to the atmosphere during normal operation and / or ii) has at least one gas inlet opening for the controlled (active) introduction of gas into the tempering chamber.

[0059] Here, "in intended operation" refers to the state of the annealing furnace, in particular a largely mechanically closed state of the annealing furnace, in which the annealing of a fiber inserted in the annealing chamber takes place. Furthermore, "open to the atmosphere" means that a wall opening and / or a feed channel is provided through which the fiber or fiber bundle can be introduced into the annealing chamber and, in parallel, a gas or gas mixture, especially air, can flow into the annealing chamber.

[0060] In a tempering furnace intended for a batch or continuous process, the fiber inlet and / or the fiber outlet can be designed as an inlet or outlet opening, such as a material recess. In an improvement of this embodiment, a lock chamber can be provided, in particular a heatable lock chamber, which is preferably heated with a heating gas, in order to limit the entry of cold and / or unconditioned ambient air. The heating gas can be air, an O2-containing gas mixture, or an inert gas, such as nitrogen (N2) or carbon dioxide (CO2). However, it has been shown that the passive entry of ambient air has no adverse effect on fiber quality, in particular not on selectivity and / or permeance.

[0061] To improve the controllability and regulation of the tempering furnace, in a further advantageous embodiment, the tempering furnace can comprise a gas supply line, in particular into the interior space comprising the at least one IR emitter (tempering chamber), wherein a gas (gas mixture) can be introduced into the tempering furnace by means of a connected or connectable ventilation station. In particular, air can be introduced into the interior of the tempering furnace. The gas supply line can comprise one or more inlet openings into the tempering furnace. Furthermore, the tempering furnace can comprise a gas outlet, in particular from the interior space comprising the at least one IR emitter, for discharging the hot gas mixture. The gas outlet can comprise one or more outlet openings from the tempering furnace.

[0062] The direct gas introduction into the annealing furnace provides a beneficial degree of freedom for controlling and regulating the furnace, allowing the fiber to be immediately protected, for example, in the event of temporary overheating of the annealing furnace components, without interrupting production. All of the aforementioned devices, elements, and components include all the necessary sensors and control and regulation units, or are connectable or connected to them.

[0063] In a further advantageous embodiment, the ventilation station is alternatively or additionally designed to introduce or pass an inert gas, in particular nitrogen (N2), into the tempering furnace. Advantageously, the ventilation station is designed to create a largely oxygen-free atmosphere in the tempering furnace. This can, in particular, consist of an oxygen content below 1000 ppm, advantageously below 500 ppm, ideally below 200 ppm.

[0064] The gas flow within the annealing furnace, and especially in the annealing chamber, is not limited and can be directly along or across the fiber and / or indirectly through internal chambers of the annealing furnace, which are separated from the interior space surrounding the fiber by components such as reflectors or partition walls. Gas flow or inflow parallel or largely parallel to the fiber is particularly advantageous, resulting in lower mechanical stress and vibrations in the fiber or fiber bundle.

[0065] In one advantageous embodiment, the tempering furnace itself has a cooling unit, in particular a cooling unit operated with a fluid, such as water. In another advantageous embodiment of the system, the IR emitter of the tempering furnace can have a power, based on the length (ms) of the IR emitter in meters, of at least 7.5 kW / rriE, advantageously of at least 10.0 kW / rriE, and ideally of at least 15 kW / rriE. The power of the IR emitter is advantageously max. 100 kW / rriE, preferably max. 50 kW / rriE, and ideally max. 35 kW / rriE. In particular, IR emitters that can be operated at a power of 8 to 17.5 kW / rriE can anneal a polymeric hollow fiber or a bundle of up to 100 individual fibers within a time of less than 15 s, ideally less than 10 s, and achieve permeances and selectivities that meet specifications.

[0066] In addition to the at least one IR emitter in the interior space surrounding the fiber (annealing chamber), the interior of the annealing furnace can have one or more reflectors. At least one reflector can be attached to a wall of the IR emitter or form at least part of a wall or wall section of the annealing furnace.

[0067] In a further advantageous embodiment, the tempering furnace can be designed in two or more parts and, for this purpose, has at least two mutually shielded (furnace) interiors or (furnace) sections. Such a tempering furnace is designed to heat the fiber in a first interior or section for a first treatment duration using a first IR radiation power in at least one heating step, and to temper the fiber downstream in a further interior or section for a further treatment duration using a further IR radiation power different from the first in at least one power step.Here, "shielded" means that at least one separating and / or deflecting element, in particular a separating element with a suitable small passage opening, is provided, so that, in particular, the IR radiation from the further interior space or section does not reach the first interior space or section in which the fiber heating can be carried out. The separating element can also be a lock element or intermediate space without a heating element, in particular without an IR emitter.

[0068] In a further advantageous embodiment, at least one fiber storage device can be provided before and / or after the annealing station, so that the fiber or bundle can be conveyed within the annealing station at a reduced conveying speed or at least temporarily stopped, i.e., can have a conveying speed of 0 m / s for a defined portion of the annealing period. Ideally, the fiber storage device is motor-driven and / or controllable; particularly advantageously, the fiber storage device is integrated into an adjacent treatment unit.

[0069] Advantageously, the system provides for the annealing furnace and / or the IR emitter to be channel- or channel-like and to have at least two walls or wall sections parallel to the local transport direction of the fiber, in particular in the direction of the fiber's longitudinal axis (AF), wherein the walls or wall sections can be covered with the aforementioned reflectors or at least partially formed therefrom. Thus, a fiber is guided uncut on a strand through the annealing station or the IR emitter and annealed during transport in the direction of the fiber axis. Thus, in this embodiment, the IR emitter can have an inlet opening and an outlet opening into which the fiber is continuously fed and discharged.To improve the controllability of the annealing step and the IR emitter, the IR emitter can comprise at least one guide and deflection mechanism, in particular a movable deflection mechanism, by means of which the fiber is deflected at least once in the region of and / or within the IR emitter. It is particularly advantageous if the guide and deflection mechanism is adjustable, in particular motor-driven, so that the residence time (annealing time) of a fiber or a fiber section in the IR emitter, and in particular in the region of the IR radiation, can be controlled as needed.

[0070] In a highly economical embodiment of the IR emitter or annealing station, it is configured as a lane or channel with walls parallel to the transport direction, in particular the fiber's longitudinal axis, with at least one IR radiation source being rod-shaped and also aligned parallel or largely parallel to the transport direction, in particular the fiber's longitudinal axis. In principle, the position and number of IR emitters relative to the conveyed fiber are not restricted, provided the expert observes the quality-relevant parameters, such as the emitter's radiation power, the duration of exposure to the fiber, and the uniformity of the radiation conduction to the fiber.

[0071] According to a very advantageous embodiment of the system, or analogously also of the method, the system and the method can be designed to continuously transport the fiber or fiber bundle from the spinning unit to at least the exit of the tempering station. In particular, it is advantageous to continuously transport the individual fibers uncut on the strand, or the at least one fiber bundle uncut on the strand, from the spinning unit through the tempering station.

[0072] In this context, “continuous” conveying or transport of the fiber also includes at least temporary intermediate storage and / or stacking in a fiber storage facility.

[0073] The at least one tempering station with the at least one tempering furnace can advantageously be arranged at one of the following plant locations:

[0074] Downstream of the washing unit, wherein no (further) thermal treatment station of the thermal treatment unit is arranged upstream of the tempering station, Downstream of at least one dehumidification station of the thermal treatment unit, Downstream of at least one drying station, in particular downstream of a drying station which is arranged downstream of a coating station or application station.

[0075] Overall, the tempering station serves in particular to finally temper the (raw) fiber that is (externally) wet or has (internally) residual moisture from, for example, detergent, solvent and / or exchange medium, so that the expert can provide a corresponding plant location at which the fiber arrives wet, i.e. undried or with a defined residual moisture after passing through a drying station.

[0076] A "wet fiber" here means that the fiber has not yet undergone a thermal treatment station after the washing unit, or that adhering (external) fluids have only been stripped off, dripped off, and / or roughly removed with a gas jet under pressure or vacuum. The annealing station is usually located after and outside the washing unit.

[0077] In a particularly advantageous embodiment of the system, a processing unit is arranged downstream of the tempering station. The processing unit can in particular comprise at least one winding wheel or a bundling tool and / or an applicator. Overall, the term “processing unit” should not be understood in a restrictive manner and describes a unit in which any type of temporary or permanent connection of individual fibers takes place. In particular, individual fibers or a fiber bundle can be wound up continuously, uncut, using the winding wheel until the winding wheel is fully loaded, and then cut and subsequently cut to a defined length and / or processed in some other way. A bundling tool can additionally or alternatively be used to temporarily or permanently bundle a (sub)group of fibers.For example, all or a portion of the uncut fibers are wrapped inline and, if necessary, tensioned against each other. For tensioning, a band, a sleeve, or other wrapping material can be wrapped around the fiber group and suitably secured. The finishing unit can be fully or partially enclosed by the post-treatment unit or connected to the post-treatment station. The bundled groups of individual fibers (fiber bundles) can advantageously be cut in the wrapping area; however, this is not to be understood as restrictive, and the cut can be made in front of, behind, or through the band, the sleeve, or the wrapping material in the transport direction of the fiber bundle.

[0078] Alternatively, the assembly unit is arranged upstream of the annealing station, wherein the annealing station comprises at least one annealing furnace with at least one IR emitter.

[0079] A further advantageous embodiment of the system provides for a fiber storage unit, also called a "band storage unit." This unit can be located, in particular, upstream of the tempering station. This fiber storage unit is advantageously equipped with movable deflection elements that are motor-driven and / or controllable. This allows fibers to be produced continuously upstream of the tempering station, while downstream of the fiber storage unit, the fibers or the (fiber) bundle can be withdrawn discontinuously and / or at different speeds. In particular, the fiber storage unit can enable the fiber and / or fiber bundle to be stopped in the tempering station.

[0080] In a further advantageous embodiment, the assembly unit comprises a cutting device for the fibers or the fiber group. In particular, a cutting device by means of which the conveyed fibers or fiber group can be cut inline. For this purpose, it is particularly advantageous if the bundling tool and / or the cutting device can be moved and / or pivoted in the conveying direction of the fiber in order to avoid interruption of fiber production. The assembly unit can further be designed to form a (final) bundle of yxn fibers or the y sub-bundles from a plurality of y sub-bundles each comprising n fibers and to fix it at least temporarily.

[0081] In this case, “temporarily fix” means that the fibers of such a group are fixed to one another, for example tensioned, in such a way that they can be transported and / or further processed as a group and the falling out of an individual fiber is reliably prevented.

[0082] Typically, the formation of such (partial) or (final) bundles from a plurality of fibers is followed by gluing (potting) and final processing, i.e. formation of the filter cartridge, or the production of the filter module with insertion of the filter cartridge.

[0083] In a further advantageous embodiment, the post-treatment unit of the system comprises a discharge station. This is used, in particular, at the entrance to a drying unit or at the entrance to a finishing unit to dissipate interfering electrical charges. For this purpose, for example, a spray medium containing an electrolyte and / or an iron-containing substance is applied to the fibers. In an alternative embodiment, the electrical discharge occurs through contact, in particular sliding contact, with a grounded electrical conductor.

[0084] In a further advantageous embodiment, the post-treatment unit of the system comprises a coating station, wherein the coating station is used to apply at least one coating to the separation layer made of, for example, a polymer material on the base fiber, wherein the separation layer with the coating and the entire fiber or the at least one fiber bundle must subsequently be subjected to annealing in the annealing oven in order to set the desired separation properties of the hollow fiber membrane.

[0085] In a very advantageous embodiment, polydimethylsiloxane (PDMS) can be applied as a coating agent in the coating station (coating step), for example, using a spray device or an immersion bath. In the case of an ISA membrane, the PDMS coating serves, for example, to seal surface defects in the separation layer and may also slightly influence the separation properties of the separation layer. A fiber coated in this way is then advantageously dried in a drying station and subsequently annealed downstream, with the desired separation properties of the hollow fiber being developed overall in the annealing step using IR radiation. Ideally, each coating station is followed by a drying station.

[0086] The hollow fibers used for gas separation can be of two basic types: i) ISA membranes

[0087] These have a support structure and a thin outer layer as a separating layer, whereby the support structure and the outer separating layer are produced monolithically from the same material in the spinning process and specific high separating properties are formed in the annealing step by means of IR radiation. A first separating layer is formed when the solvent is exchanged (displaced) in the fixing station of the exchange unit, since a compacted layer in the form of a skin is formed on the outside of the membrane due to the displacement of the solvent. The thickness of this separating layer can be adjusted, for example, by the distance between the spinneret and the fixing bath. In a further advantageous embodiment, the separating layer orCoating the fiber with the aforementioned separation layer with at least one polymer material different from the base fiber (coating step), in particular with the polymer material polydimethylsiloxane (PDMS). ii) Asymmetric composite membrane (AK membrane), which comprises a base fiber as the basic or carrier structure and an applied outer separation layer, wherein at least one further coating layer may be included.

[0088] For this purpose, a porous base fiber is spun in a spinning device and the subsequent exchange steps, which, unlike the ISA membrane, does not yet have an outer separation layer. This base fiber is then coated with at least one material different from the base fiber as an outer separation layer in an application station (coating step). This separation layer can i) comprise or essentially consist of a polymer material that corresponds to one of the polymer solutions described herein, such as aromatic polyimide, aromatic polyetherimide, aromatic polypolyamides, polyarylene ethers, aromatic polybenzimidazoles and / or mixtures thereof, where appropriateat least one 2D or 3D filler may be included, such as zeolites or metal-organic framework materials or ii) be formed essentially from an inorganic material, such as at least one zeolite and / or at least one metal-organic compound, wherein suitable binders may be provided.

[0089] The base fiber and / or the separation layer of an AK membrane according to i) or ii) can be provided with a coating, in particular polydimethylsiloxane (PDMS), in a manner similar to the ISA membrane.

[0090] In one embodiment of the system and method, at least one application station or coating step can be provided for applying a separation layer to a base fiber to produce an AK membrane. Furthermore, at least one coating station can be provided, as described above.

[0091] According to the invention, the two aforementioned basic types of hollow fiber membrane are finally annealed in the annealing oven using IR radiation, whereby the desired high separation properties are formed.

[0092] Advantageously, a drying station is located immediately downstream of the at least one application station and / or the at least one coating station, in particular a drying station is provided immediately downstream of each application station and / or coating station.

[0093] The invention further comprises a method for producing a fiber which is spun from a polymer substrate, wherein the fiber is in particular a hollow fiber for gas separation, and comprising the following steps:

[0094] - spinning step of the fiber from the polymer solution,

[0095] - Exchange step for exchanging a solvent, in particular an aqueous solvent, wherein the exchange step may comprise at least one fixing step with a liquid fixing medium and / or at least one washing step in / with a washing medium, in particular in a basin with a washing medium, wherein the washing step may in particular follow the fixing step,

[0096] - at least one drying step comprising a tempering step in which the fiber is heated to a temperature below the glass softening temperature of the polymer substrate, wherein the fiber is heated, ie tempered, in the tempering step by means of at least one continuously operated tempering furnace (251) by IR emitters.

[0097] In this case, as already explained above with regard to the system, in an advantageous version of the method it can be provided that in the tempering step the fiber is tempered or heated in such a way that the fiber is heated for a defined time (tempering time), also called tempering time, to a temperature which is below the glass softening temperature (TG), in particular and also i) in the range up to 80 °C below the glass softening temperature (TG), and / or ii) in the range of greater than 250 °C.

[0098] In a further advantageous embodiment of the method, it can be provided that the fiber is tempered or heated during the tempering step in such a way that the fiber is heated for a defined time (tempering time) i) to a limit temperature which is max. 1 °C, in particular max. 4 °C below the glass softening temperature (TG), in particular to a limit temperature in the range from 70 °C to 1 °C below the glass softening temperature (TG), preferably to heat in the range from 65 °C to 1 °C and / or ii) the fiber is heated to a temperature of greater than 280 °C to 450 °C and below the glass softening temperature (TG).

[0099] It is particularly advantageous to maintain a distance of max. 1 °C to 4 °C from the glass softening temperature (TG) in order not to damage the structure, in particular the desired porosity, of the hollow fiber. To avoid damage to the fiber due to fluctuations in the heating temperature, it may be preferable to provide a distance of max. 1.5 °C, 2 °C, 2.5 °C, 3 °C or 3.5 °C from the TG instead of the aforementioned max. 1 °C distance from the TG. The respective max. temperature distance from the TG can be provided depending on the respective fiber material and on the system and / or the process.

[0100] In this context, "max. 1 °C, in particular max. 4 °C" means that it is particularly advantageous to maintain a distance of at least 1 °C, 1.5 °C, up to, for example, 4 °C from the respective glass softening temperature (TG) of the fiber material (polymer substrate) in order to avoid damaging the structure, especially the desired porosity, of the hollow fiber. This applies analogously to the degradation or decomposition temperature (Tz).

[0101] Even if a single fiber is discussed here, a group of individual fibers or a fiber bundle can also be treated in an analogous manner. In particular, one process variant involves treating a fiber bundle consisting of n individual fibers of up to n = 600 using IR radiation, as described above. It can be advantageous if the individual fibers in a fiber bundle are twisted, twisted, or tangled with each other with respect to a common (theoretical) central longitudinal axis. This has the advantage that the individual fibers come into closer contact, are thus more densely packed, and the risk of fiber breakage in individual fibers is reduced during shrinkage processes.

[0102] In a preferred process variant, the fiber can be treated during the annealing step using the IR emitter with an IR radiation power based on the emitter length in meters (IDE) of at least 5.0 kW / rriE, preferably at least 7.5 kW / rriE, and ideally at least 10 kW / rriE. It may also be advantageous if the IR radiation power is max. 100 kW / rriE, advantageously max. 50 kW / rriE, and ideally max. 35 kW / rriE.

[0103] All aspects and advantages described herein in connection with the plant apply identically or analogously to the process and vice versa, unless they are technically mutually exclusive or impossible.

[0104] Advantageously, the annealing step takes place in an inert or largely inert atmosphere in which the O2 content in the annealing furnace is below 1,000 ppm, advantageously below 500 ppm, and ideally below 200 ppm. The IR radiation is advantageously introduced by the IR emitter at least on one side toward the fiber or fiber bundle in the annealing furnace and advantageously distributed by reflection from at least one reflector within the annealing furnace.

[0105] A surprising and outstanding effect was found: the total annealing time using an IR emitter for a bundle of up to 80 individual fibers requires only 0.1% of the annealing time, for example, compared to a conventional annealing oven, such as a forced-air or convection oven. According to an advantageous embodiment of the method, the annealing time can thus be in the range of 0.1 to 60 s, preferably 0.5 to 30 s, ideally 1 to 20 s.

[0106] A further embodiment of the process can consist in the tempering step consisting of at least two sub-steps, namely a

[0107] 1) heating step in which the IR radiation power is in the range of 5 to 25% of the maximum IR radiation power, advantageously 7.5 to 15%, ideally 10%; and

[0108] 2) Power step in which the defined maximum IR radiation power is emitted by the IR emitter of the tempering furnace.

[0109] The duration of the heating step is advantageously 1 / 6 to 1 / 3 of the power step, wherein the power step is advantageously in the range of approximately 0.1 to 60 s, preferably 0.5 to 30 s, ideally 1 to 20 s.

[0110] Even though a distinction is made here between “annealing step” and “power step”, “annealing step” is sometimes also used synonymously with the “power step”, in which the maximum radiation power is emitted by the IR emitter.

[0111] In an advantageous embodiment of the method, it can be provided that

[0112] - the liquid polymer solution and / or

[0113] - the fiber spun from the polymer solution or the substrate, after fixation and / or after at least one thermal treatment station of the thermal treatment unit, has an extinction value E of less than 0.5; advantageously of less than 0.3; ideally of less than 0.2; wherein the extinction value E is defined as the quotient E = Ig (hn / lout) with lout being the intensity of the incident IR radiation and lout being the intensity of the exiting IR radiation.

[0114] The extinction of the IR radiation is determined depending on the wavelength and the layer thickness.

[0115] The absorbance of the liquid or reliquefied polymer solution can be measured, depending on the wavelength range, using a Vis spectrophotometer, such as the Specord 210 plus UV-VIS spectrometer from Analytik Jena and / or an IR spectrometer, such as the Vertex 70 FT-IR spectrometer from Bruker Corporation. Liquid polymer samples were placed in a cuvette of the respective spectrometer. A solid sample (a piece of foil) was placed in a connected sample holder of the aforementioned spectrometer and measured. The wavelengths were partially limited by the respective spectrometer and, if necessary, additionally resolved by a detector in the sample holder. The corresponding sample holder for solids of the UV-VIS spectrometer is an integrating sphere from Analytik Jena, while that of the Vertex 70 FT-IR spectrometer, for example, is the Integration Sphere from Bruker.

[0116] The VERTEX 70 spectrometer was able to cover the spectral range from 10 cm-1 (far IR / THz range), the mid and near IR range up to the visible / UV spectral range (28,000 cm' 1 ) can be measured.

[0117] To measure the solid substrate, film pieces were prepared. A 25% polymer solution (e.g., containing polyimide) was applied to a glass plate with the solvent used in production and brought to a defined layer thickness of 0.5 mm using a casting knife. The solvent was then evaporated under an inert atmosphere in an oven at approximately 80 °C for at least 60 minutes. The solidified film pieces were then removed from the glass plate with water and dried again. The thickness of the solidified film pieces ranged from 30 μm to 120 μm.

[0118] The piece of film produced in this way was placed in the respective sample holder and the extinction or the extinction coefficient of the transmitted beam through the piece of film was recorded with the respective spectrometer as a function of wavelength.

[0119] It has proven particularly advantageous if the extinction (IR absorption) of the fiber or of an analogous polymer substrate (solid) or of the polymer solution (liquid) with respect to IR radiation is in the range from 0.6 to 1.8 pm, ideally in the range from 0.75 to 1.75. In other words, it is advantageous if the solidified, unannealed polymer substrate in particular is largely transparent to the aforementioned wavelengths of IR radiation, so that very good, homogeneous heating of all fibers is possible, even for a fiber bundle. The wavelength range of the respective maxima of the IR radiation is particularly preferably between 800 nm and 2000 nm, with IR emitter powers based on the length of the IR radiator of 2 to 20 kW / rriE.

[0120] Surprisingly, it was observed that, due to the aforementioned low extinction in the wavelength ranges mentioned, even a large group of individual fibers can be annealed as a (dense) bundle, which nevertheless exhibits very homogeneous separation properties in terms of permeance and selectivity as individual fibers. In the present experiments, groups of up to 100 individual fibers were successfully annealed as fiber bundles using IR radiation, achieving the required specifications analogous to the conventionally annealed fibers.

[0121] In a further embodiment of the process, it may be advantageous for the fiber to be conveyed during at least part of the annealing step. Advantageously, the fiber is conveyed throughout the entire annealing step.

[0122] According to a further improved method variant, it can be provided that the tempering furnace i) is open to the atmosphere, in particular has an inlet or outlet opening for the fiber and a passive gas or air introduction takes place with the conveyed fiber into the tempering furnace and / or ii) comprises or can be connected to a ventilation station, via which a gas mixture), in particular air, N2 and / or CO2, is introduced into the interior (tempering chamber) of the tempering furnace.

[0123] In alternative embodiments of the process, as described above for the tempering furnace, gas is guided via locks.

[0124] Thus, in a further advantageous embodiment of the method, the tempering furnace can be open to the atmosphere. In this case, atmospheric gas (air) can be passed through the fiber inlet and / or the fiber outlet as an inlet or outlet opening for a continuous process. In a simple method variant, no lock chamber is provided. In an improvement of this embodiment, a lock chamber can be provided, in particular a heatable lock chamber, via which an initial temperature control of the fiber and shielding of the interior of the tempering furnace takes place. Preferably, a heating gas is introduced into the lock chamber in order to limit the entry of cold or strongly temperature-fluctuating ambient air or to reduce the thermal stress on the fiber at the outlet. Alternatively, the lock chamber can comprise a heating element.The heating gas can be a gas mixture, such as air or a gas mixture containing O2. Alternatively or additionally, the gas (mixture) can comprise at least one inert gas, such as nitrogen (N2) or carbon dioxide (CO2).

[0125] To improve the controllability of the manufacturing process, a further advantageous embodiment provides for a gas supply, particularly into the interior space containing the at least one IR emitter. A gas mixture, particularly air, is introduced into the interior space by means of a connected or connectable ventilation station in the tempering furnace, for example, using an (active) compressor. The gas supply can be provided via one or more inlet openings in the tempering furnace, with a gas outlet provided.

[0126] The direct gas introduction provides a degree of freedom for controlling and regulating the furnace for the process and effectively protects the fiber in the event of, for example, temporary overheating of the components of the annealing furnace, without interrupting the process.

[0127] Even though the system and method are primarily described for continuous tempering, the present invention is not limited to this. The IR emitter can also be a batch unit, so that the fibers, a fiber bundle, or a group of fiber bundles are tempered in batch operation using at least one IR emitter. For this purpose, the fibers are advantageously cut to a desired length before tempering and / or advantageously fixed at least temporarily as (partial) bundles, analogous to the treatment units of the systems described herein. For batch tempering, it is generally advantageous to temper the individual fibers or fiber bundles while hanging vertically in the axial direction, so that the individual fibers remain largely aligned parallel to one another.

[0128] Absorption is a measure of the attenuation of the intensity of light or radiation, including IR radiation, through adsorption or scattering after the beam has passed through a material. Absorption is measured using spectrometers.

[0129] The inventive solution is described in detail below using exemplary embodiments. It shows:

[0130] Fig. 1 the system in a first embodiment;

[0131] Fig. 2 the system in a second embodiment;

[0132] Fig. 3 the system in a third embodiment;

[0133] Fig. 4 the system in a fourth embodiment;

[0134] Fig. 5 the system in a fifth embodiment;

[0135] Fig. 6 two variants for the transport of the fiber in the annealing station;

[0136] Fig. 7 shows the experimental setup as a schematic representation;

[0137] Fig. 8 shows a graph comparing the temperature profiles from the tests with the known annealing; Fig. 9 shows a graph of extinction versus the IR spectral radiation of an emitter, along with nine characteristic curves;

[0138] Fig. 10 four graphs in two partial representations I., II., comparing bundles of 10 and 80 individual fibers with regard to permeance and selectivity;

[0139] Fig. 11 two graphs for different fiber bundles, as normalized permeance; selectivity against the introduced radiation energy and

[0140] Fig. 12 shows a graph of comparative transmission measurements.

[0141] The system 100, as shown in Figure 1, has a main conveying direction A, which is shown from left to right and represents the x-direction in a Cartesian system. The system 100 comprises a control and regulation unit 130, a feed and supply unit 140, a spinning unit 106, a fixing unit 150, a washing unit 160, and a post-treatment unit 170. The post-treatment unit 170 comprises a thermal treatment unit 200, with a drying station 210 of the inventive tempering station 250, and a finishing unit 180. The fiber 110 is transported through the system 100 in the main conveying direction A and is deflected and redirected several times in the y-direction or z-direction along partial sections. The control and regulation unit 130 is connected to the system 100 or parts thereof via data lines 132, as sketched by way of example with a dash-dotted line.

[0142] Other elements for the power and data lines, as well as the automation of such a system 100, are generally known to those skilled in the art and are not further described here. The storage and feed unit 140 is also only shown in outline and comprises tanks 142 or a tank storage facility for media, in particular for the polymer solution 102 from which the fiber 110 is formed, as well as process media 104, a pump (unit) 146, and an (inert) gas reservoir. These are connected to the spinning unit 106 in a media-conducting manner. The fiber 110 is formed in the spinning unit 106 in a manner not described in detail, as described, for example, for a hollow fiber from a polymer solution in WO 2014 / 202324 A1. Alternatively, the fiber can also be obtained from a polymer melt, in particular as a hollow fiber.The process media 104 are in particular the process media required during the spinning process, such as in particular the core fluid for forming the inner cavity of the respective individual fiber 110.

[0143] The freshly formed fiber 110 is introduced into the fixing medium, a non-solvent, of the fixing unit 150 and guided out of the basin of the fixing unit 150 via guide rollers 108. The individual fibers 110 are oriented in the y-direction at a defined spacing from one another by means of comb-like or multi-finger-shaped lane guides 109. The washing unit 160 comprises a plurality of guide rollers 108 arranged below the fluid level of the washing liquid and by means of which the fibers 110 are held in the washing liquid, in particular in an organic washing liquid, for a defined running time in order to remove the non-solvent from the fiber 110. In a manner not shown, the washing unit 160 can comprise several basins connected in series.The drying station 210 is connected downstream of the washing unit 160. In a grouping station 260 at the entrance to the drying station 210, the fibers 110 are gathered into a bundle 112 and guided as a strand through the drying stations via diverter rollers 108. The drying station 210 is connected to a gas supply line 212 and a gas discharge line 214, with a heat exchanger 216 for heating the supply line C being connected to the gas supply line 212. The supply line C is, in particular, dehumidified air. Within the drying station 210, the bundle 112 is deflected several times as a strand by deflector rollers 108, while the heated gas flows around it and dries it.The deflection rollers 108 are usually static bodies over which the conveyed fiber 110 or the bundle 112 is pulled, wherein in embodiments not shown it may be advantageous to drive at least individual deflection rollers 108 in such a way that they rotate about their own longitudinal axis and in the direction of the fiber longitudinal axis AF and thus reduce the tension within the fiber 110 or the bundle 110.

[0144] The tempering station 250, connected in the main conveying direction A, comprises a tempering furnace 251 as the central element with an IR emitter 252 and a reflector 254, both of which are arranged in a housing 256 of the tempering furnace 251. The tempering furnace 251 is designed as a channel and continuously receives the pre-dried bundle 112 at the inlet side for a tempering time (throughput time) of approximately 10 s, wherein the tempering time can be divided into two or more sub-steps, such as a heating step and a power step.

[0145] The annealing station 250 or the annealing furnace 251 is connected to a gas supply unit 270 and a gas discharge unit 272, with a compressor 226 and a gas filter unit 274 being part of the gas discharge unit 272. The gas supply and discharge lines 270, 272 are part of a ventilation unit, with the gas supply line 270 being connected to an inert gas source. At the discharge end of the annealing station 250 opposite the inlet side, a conveying means 280 is arranged, which is designed as a forming and conveying unit and conveys the (fiber) bundle 112 in a compressed state to the assembly unit 180. Within the drying station 210, the bundle 112 can be guided vertically (z-direction) in sections (multiple times) by corresponding deflections 108 or, as shown in Figure 3, for example, can be guided horizontally (multiple times) (x-direction).Here, “vertical” or “horizontal” means the main orientation for the purpose of linguistic illustration and also includes (slightly) inclined orientations.

[0146] The assembly unit 180 comprises a fixing station 182, a cutting station 184, a lifting unit 186, and a transport element 188. The bundle 112 is transported to the assembly unit 180 via the conveyor 280, where it is fixed as a group (fiber bundle) at the free end and / or in the separation or cutting area of ​​the bundle using at least one fixing means (not shown in detail), such as a band, a ribbon, a cord, etc., in particular by wrapping it multiple times and thus fixing it as a group. In parallel or subsequently, the bundle 112 is grasped by the lifting unit 186, which in the illustrated embodiment is designed as an xyz lifting and gripping unit. In the cutting station 184 and a separating means symbolically represented as a knife blade, a bundle 112 is cut to a desired length from the bundle strand, which is then temporarily stored or stacked as the finished bundle 112, if necessary.

[0147] The assembled bundles 112 are then discharged from the assembly unit 180 in the forwarding direction B by means of the transport means 188.

[0148] The system 100 shown in Figure 2 differs from the system shown in Figure 1, particularly in that no drying station 210 is provided, but rather the fibers 110, after the washing unit 150, are fed directly into the tempering station 250 or the tempering oven 251, which can basically be designed analogously to the aforementioned tempering station 250 from Figure 1. The tempering station 250 is connected downstream of the washing unit 160, wherein in a grouping station 260 at the entrance to the tempering station 250, the fibers 110 are gathered into a bundle 112 and are guided as a strand in a straight line, i.e., without further deflection, through the tempering station 250. A dehumidification station 220 is arranged on the outgoing conveyor line and above the washing unit 160, which, in the area of ​​the deflection roller 108 there, drives the liquid adhering to the fiber 110 back into the basin of the washing unit 160 by means of the nozzle units 222.

[0149] The lower detailed illustration, outlined in dashed lines, shows the top view of the guidance of the fibers 110 at the transition from the washing unit 160 to the tempering station 250 and the grouping station 260 there. Two further, analogous top views are shown in Figure 6. As shown in the detailed view of Figure 2, at the exit of the washing unit 160, the fibers are spaced apart from one another in the y-direction by means of the lane guide 109 and compressed downstream by the lateral guide rails 262 of the grouping station 260 into a bundle 112 of the then touching individual fibers 110.

[0150] Compaction occurs in the y-direction and in the z-direction, whereby additional height guides (not shown) analogous to the lateral guide rails 262 can be provided in order to carry out the compaction in the z-direction in a mechanically defined manner and to avoid deformation of the hollow fiber geometry. For this purpose, at least two groups of the fibers to be bundled are guided through such height guides at different heights (z-direction) for a defined conveying distance before they are deposited on top of one another in the z-direction and formed into a common bundle 112. This system design without a drying station 210 and the associated process control has been made possible by the use of an annealing station 250 with an IR emitter 256 because it has surprisingly been found that continuous annealing makes it possible to prevent sticking even of initially relatively wet individual fibers 110 in the bundle 112.In other words, even relatively moist fiber bundles 112 can be tempered by means of IR radiation without or after only slight drying.

[0151] The elimination of drying station 210 and the associated pipes and units will result in significant energy savings and a significant reduction in the space required by the plants.

[0152] Figure 3 shows, in a highly schematic manner, the system 100 and the fiber 110, as well as the bundle 112 on its path through the system 100. In addition to, or in contrast to, the exemplary embodiments of Figures 1 and 2, the system 100 comprises a coating station 120 and a discharge station 190, which are known in principle. The aforementioned grouping stations are not shown in Figure 3 and can be provided as needed. Analogous to the system 100 shown in Figure 1, the at least temporary winding, stacking and / or cutting of the fiber bundles 112 takes place in the assembly unit 180. Differently, in this system embodiment, the assembled and cut fiber bundles 112, in particular a plurality of at least temporarily assembled fiber bundles 112, are annealed batchwise in a annealing oven 251 of the annealing station 250 downstream of the assembly unit 180 by means of an IR emitter (not shown).

[0153] In the exemplary embodiment of Figure 4, in contrast to the system variant of Figure 4, the annealing furnace 251 of the annealing station 250 is arranged upstream of the assembly unit 180. The spaced-apart individual fibers 110 or the at least one fiber bundle 112 are continuously transported and annealed through the annealing furnace 251. In particular, the transport speed and / or the length of the annealing furnace 251 are dimensioned and / or coordinated such that the required residence time (annealing time) of the individual fibers 110 or the at least one fiber bundle 112 in the area of ​​influence of the IR emitter (not shown) can be maintained.

[0154] In the embodiment of Figure 5, in contrast to the previous embodiments of Figures 1 to 4, the invention additionally includes a fiber storage 230, which is arranged upstream of the tempering station 250 as part of the thermal treatment unit 200. Thus, a storage step for the fibers 110 or the bundle 112 can take place before the tempering step.

[0155] The fiber storage 230 has two opposing groups of deflection elements 232, which can be dynamically driven individually or as a group to change their relative position to one another. In this way, a defined fiber length or bundle length can be stored, while, for example, downstream of the fiber storage 230, the fibers 110 or the fiber bundle 120 are transported more slowly or temporarily stopped than is the case upstream of the fiber storage 230.In other words, the system has a first conveyor section F1, in which the fibers can be conveyed at a first conveyor speed v1, in particular can be conveyed continuously, and a second conveyor section F2, in which the fibers can be conveyed at a second conveyor speed v2, in particular can be conveyed discontinuously and / or at a variable speed, wherein a (dynamic) fiber storage 230 is arranged between and / or in the transition from the conveyor section F1 and the conveyor section F2.

[0156] The conveyor line F1 comprises the spinning unit 106, the fixing unit 150, and the washing unit 160, and the conveyor line F2 comprises the tempering station 250 with the tempering furnace 251. A strand drive can be provided in the area of ​​the conveyor line F1 and / or F2 (in each case) to draw the fibers 110 or the bundle 122. In particular, in the conveyor line F2, the strand drive serves to completely or partially empty the fiber storage 230 and / or to accelerate the fibers 110 or the bundle(s) 112, as an acceleration means out of the tempering station 250.

[0157] In this embodiment, in particular the storage capacity of the motor-driven fiber storage 230, the possible acceleration and transport speed of the fiber storage 230 during the accelerated removal of the stored fibers 110, 112 and the length of the tempering furnace 251 are dimensioned and / or coordinated with one another in such a way that the required residence time (tempering time) of the individual fibers 110 or of the at least one fiber bundle 112 in the area of ​​influence of the IR emitters (not shown) can be maintained.

[0158] Figure 6 shows a plan view of two further embodiments of grouping stations 260 and the alignments and positions of individual fibers 110 produced thereby in the annealing station 250. Partial view I shows grouping station 260, which essentially consists of two comb-like or multi-finger-like lane guides 109, wherein the two opposing lane guides 109 have different spacings between the individual fingers or individual guides. Both lane guides have the same number of individual fingers, or the number of individual fingers depends on the number of parallel-guided individual fibers 110. Depending on the cross-sectional area and geometry of the individual fingers, individual fibers 110 can be located on each side of individual fingers.

[0159] The lane guide 109 arranged at the entrance of the annealing station 250 and the annealing furnace 251 brings the individual fibers 110 closer to each other, for example, to within 2 mm to 3 mm. No compaction occurs until the parallel individual fibers 110 touch each other, and the individual fibers 110 essentially span a common plane with their fiber longitudinal axes. Although this embodiment is the most complex in terms of construction, it enables the shortest annealing times for the fibers 110 and thus requires the shortest extension of the annealing station 250 in the main conveying direction (x-direction). Optionally, a second grouping station 260 can be arranged downstream, by means of which the final bundle is formed.

[0160] Partial view II shows the grouping station 260 (here 260.1), which also essentially consists of two comb- or multi-finger-like lane guides 109, whereby the two opposing lane guides 109 also have different spacings between the individual fingers or individual guides. The lane guide 109 arranged at the inlet of the tempering station 250 has a significantly smaller number of individual fingers or individual guides than the lane guide 109 at the exit to the washing unit 160 or the drying station 210. This is due to the fact that the grouping station 260 and the incoming lane guide 109 form several partial bundles 112 from the total number of individual fibers 110, and the subsequent partial bundles 112 are guided through the tempering station 250. In the example shown, three sub-bundles 112.1, 112.2 and 112.3, which are annealed parallel to one another in the annealing station 250 and transported through this annealing station 250. The partial bundles 112.1, 112.2 and 112.3 can subsequently be combined into a (final) bundle 112 in a second grouping station 260.2.

[0161] Even though the annealing furnace 251 is always depicted in a horizontal (lying) orientation, with the transport direction of the fiber 110 or the fiber bundle 112 aligned along the x-axis or the main transport direction A, this is not to be understood as limiting. It will be understood by those skilled in the art that the annealing furnace 251 can assume any orientation and / or inclination in space, in particular vertical or oblique. The orientation and / or transport direction of the fibers and / or the fiber bundle then follows this orientation of the annealing furnace in an analogous manner and can, in particular, also be from bottom to top or from top to bottom.

[0162] The laboratory and experimental setup shown in Figure 7 and the graphs shown in Figures 8 to 11 are described and discussed below together with the discussion of the experimental results.

[0163] Experiments and test results

[0164] The tests were carried out using an annealing station 250, as shown in Figure 7. The annealing station comprised, as its central element, an annealing furnace 251 having a closed housing 256 and in which an IR emitter 252 extended longitudinally.

[0165] The housing 256 had a base element and a head element and was designed as an elongated, cuboid-shaped body whose longitudinal axis was aligned perpendicular to the horizontal during laboratory operation. The IR emitter 252 was arranged off-center on one side and had a length of approximately 21 cm. The emitter 252 was surrounded by curved metallic reflectors 254, which had an extension of approximately 27 cm in the direction of the longitudinal axis and protruded upwards and downwards beyond the IR emitter 254 on both sides. In addition to the reflectors 254, which extended essentially parallel to the IR emitter 252, head and foot reflectors were present, so that when closed, the interior of the housing 256 had a central IR radiation chamber and a rear chamber, with essentially no IR radiation being able to enter the rear chamber.The housing 256 was divided longitudinally and connected by hinges so that it could be opened to insert or remove individual fibers or a fiber bundle (not shown in Fig. 7).

[0166] A fixing unit 258 was arranged on the head element, which was designed to hold individual fibers 110 or a fiber bundle 112 suspended. The individual fibers 110 or the fiber bundle 112 were clamped at the free, lower end with a weight 259, so that a constant tensile force could be applied to the individual fiber 110 or the fiber bundle 112. During normal operation, the weight 259 was held suspended on the fibers at a slight distance above the foot element. The fixing unit 258 and the weight 259 were arranged in the rear space, for which purpose the reflectors in the head and foot areas had a corresponding feedthrough opening.

[0167] In the footwell, a lateral guide and contact surfaces for the weight are also arranged so that a fiber bundle can be twisted or wound around the longitudinal axis once or several times as required and can be tempered in such a twisted or wound arrangement of the individual fibers in the fiber bundle.

[0168] A gas supply line 270 consisting of two lines led into the interior of the housing, through which a constant volume flow of nitrogen (N2) could be introduced. The N2 volume flow was discharged from the interior of the housing, usually continuously, via a central gas discharge line 272.

[0169] The IR emitter 252 was connected to a control unit 134 for power control, whereby the control software was stored in a connected control and regulation unit 130 and operated by a processor unit there, which in laboratory operation was a commercially available PC.

[0170] The fixing unit 258 and the weight 259 were designed to fix a fiber bundle 112 of up to 100 individual fibers 110 and to hold it under constant tensile force.

[0171] The tests were conducted in batch mode. Furthermore, a closed water cooling system was installed in the housing, which was connected to a corresponding cooling circuit.

[0172] Test procedure The supplied volume flow of N2 as inert gas was 300 ml / min and the O2 content was < 100 ppm in the interior of the housing 256. The following parameters were monitored by sensors: the N2 volume flow of the gas supply and gas outlet, the O2 concentration in the gas outlet, the temperature in the interior of the housing in the head space and in the foot space, the volume flow of the cooling water and the shrinkage of the fibers.

[0173] The weight used was 12g per 10 individual fibers, and 40 l / h of water was passed through the water cooling system as cooling water flow.

[0174] The exposure (annealing step) of the fibers to IR radiation took place in two steps:

[0175] 1) Heating step and a subsequent

[0176] 2) Performance step

[0177] During the heating step, the fiber was exposed to IR irradiation for 2 seconds at a maximum of 10% of the IR emitter's power, relative to the 100% of the intended subsequent power in the power step (target power). In this case, 100% was the maximum emitter power. During the power step, the fibers were exposed to IR irradiation at the intended maximum power (target power) for 4 to 21 seconds.

[0178] After the tempering step, the housing 256 of the tempering station 250 was immediately opened and the fibers or fiber bundle were removed without adhering to a defined cooling time or cooling curve.

[0179] Surprisingly, the separation properties, in particular the permeance and selectivity of the hollow fibers and the filter modules made from them, which had been annealed by means of IR radiation in such a short period of time, were in the range of the known, conventionally annealed hollow fibers, as explained in detail below.

[0180] Figure 8 shows a graph comparing the two annealing methods. In the graph shown, the maximum emitter power applied is normalized to 1 (left y-axis), the maximum temperature in the convection oven is also normalized to 1 (right y-axis), and plotted against the logarithmic time axis in seconds (x-axis). The inventive annealing method using IR radiation is shown essentially on the left in the graph and as a solid line. The comparative test with a conventional electric furnace (convection oven), in which the fibers were also annealed while suspended under constant tensile weight in an inert atmosphere, is shown as a dashed line.In the annealing process according to the invention, a heating step 300 was maintained for 1 s, a ramp-up 302 of the IR emitter power was also maintained for 1 s, and a power step 304 was maintained for 4 s. This was followed by a cooling step 306, which occurred through the opening of the housing 256 to the atmosphere. The ramp-up 302, or the time required for this, essentially results from the device-specific delay time to provide the maximum IR emitter power, based on the power level of the heating step.

[0181] In the comparative test, a preheating phase 400 of approximately 30 minutes was carried out, followed by a ramp-up phase 402 of the convection furnace to maximum conduction and temperature of approximately 2 hours, an annealing phase at the annealing temperature for approximately 2.0 hours and a subsequent cooling phase 406 before opening the electric furnace of approximately 0.8 hours.

[0182] The hollow fibers produced according to the invention are particularly suitable for the gas separation of CO2, O2, CH4 and N2, in particular for the gas separation of air or biogases.

[0183] The suitability of the fiber for gas separation is evaluated primarily with regard to permeance and selectivity. Permeance is the ratio of permeability to the thickness of the fiber or membrane wall and represents a measure of the gas flow through the fiber wall or membrane, thus providing an indicator of the structure and permeability of the hollow fiber or fiber bundle.

[0184] Permeability and permeance

[0185] The gas permeabilities are measured in Barrer (IO -10 cm 3 cm -2 cm s' 1 cmHg' 1 ). The permeances of the hollow fiber membranes for gases are given in GPU (Gas Permeation Unit, 10 -6 cm 3 cm- 2 s' 1 cmHg 1) or derived units. The permeance is the ratio of permeability and substrate thickness (membrane thickness) in corresponding units, such as the unit I nr 2 h 1 bear 1 .

[0186] permeability

[0187] The permeability of gases is measured using the pressure increase method. In this method, a flat foil with a thickness between 10 and 70 μm is exposed to a gas or gas mixture on one side. On the other side, the permeate side, a vacuum (approximately 10-2 mbar) is maintained at the beginning of the test. The pressure increase on the permeate side is then recorded over time.

[0188] The permeability of the polymer (substrate) can be calculated according to the following formula: P Permeability in barriers (IO -10 cm 3 (STP) cm) / (cm 2 s cmHg)

[0189] [barrer] = 1 ,333*1017 * [Nm 3 *m / (m 2*s*Pa)] with STP (Standard Temperature and Pressure): is 0 °C, 101325 Pa

[0190] Vdead volume of the permeate side in cm 3

[0191] MWGAS Molar mass of the gas in g mol 1

[0192] I Thickness of the foil in cm p Density of the gas in g cm 3

[0193] R gas constant in cm 3 cmHg K -1 mole -1

[0194] T Temperature in Kelvin

[0195] A Area of ​​the film in cm 2

[0196] A p Pressure difference between feed and permeate side in cmHg dp / dt Pressure increase per time on the permeate side in cmHg s -1

[0197] When measuring the permeance of hollow fibers, a volume increase method is used. The permeance P / l is calculated (because the thickness of the separation layer is unknown) using the following formula:

[0198] P / l permeance in GPU (Gas permeation units. 10 -6 cm3 crrr 2 s -1 cmHg -1 )

[0199] Q Gas flow of the permeate side in cm 3 (STP) / s

[0200] R gas constant in cm 3 cmHg K 1 mole 1

[0201] T Temperature in Kelvin

[0202] A Outer surface of the hollow fiber in cm 2

[0203] A p Pressure difference between feed and permeate side in cmHg dp / dt Pressure increase per time on the permeate side in cmHg s 1

[0204] The selectivities of different gas pairs are pure gas selectivities. The selectivity between two gases is calculated from the quotient of their permeabilities:

[0205] S = Pi / P2

[0206] S ideal gas selectivity

[0207] Pi permeability or permeance of the gas 1

[0208] P2Permeability or permeance of gas 2

[0209] Tests V1 to V3 Tables 1a and 1b show the comparative test (V1) and two tests according to the invention with two nominally different IR emitters (V2, V3). The annealed fibers were taken from an electric convection oven (V1) of an existing production process (comparative test). These were compared with fibers from the aforementioned test or laboratory device (V2, V3), which were annealed using IR emitters in a batch process. In tests V2 and V3, a bundle of 80 individual fibers was annealed using IR radiation in one batch run.

[0210] Table 1 a: Test conditions of tests V1 to V3 (TS - tempering step)

[0211] Table 1 b: Test results of experiments V1 to V3.

[0212] The permeance and selectivity were standardized to the values ​​of comparative test C1, i.e., the conventional annealing process. It was shown that improved permeance and consistent or slightly improved selectivity could be achieved using the annealing process according to the invention. Furthermore, it was observed that the fibers annealed using IR radiation exhibited significantly lower radial shrinkage. The radial shrinkage mentioned is the ratio of the radius of the dried and unannealed fiber (100%) to the annealed fiber. The radii of individual fibers or a group of individual fibers were measured in the laboratory using a calibrated light microscope.

[0213] Absolutely surprising and unforeseeable, the duration of the annealing process could be reduced from approximately 6 hours to less than 10 seconds with IR annealing, with the same and partly improved separation performance, permeance and selectivity of the fibers.

[0214] Experiment V4 (Fig. 9)

[0215] The set of curves in Figure 9 shows the spectral radiation spectrum of a 3.1 kW IR emitter (nominal power) with a length of 0.2 mE at different IR emitter powers in nine characteristic curves 310 to 328. The characteristic curves differ in terms of the power, which was gradually reduced by 10% starting from the outer characteristic curve 310.

[0216] At each wavelength from 0.25 to 5 pm, the absorbance of the polyimide substrate was measured as a function of the wavelength using VIS spectroscopy or NIR spectroscopy (curve 350). The absorbance is plotted against the y-axis in the range from 0 to 1, with the value 1 representing complete absorption (absorbance) and the value 0 representing complete transmission or transparency for light in the respective wavelength range (x-axis).

[0217] The IR emitter powers were measured for the outermost characteristic curve 310. The other eight characteristic curves 312 to 328 show the IR emitter power reduced by 10% each, as follows:

[0218] Curve 310 1 ,0 * 3 kW

[0219] Curve 312 0.9 * 3 kW

[0220] Curve 314 0.8 * 3 kW to

[0221] Curve 326 0.3 * 3 kW

[0222] Curve 328 0.2 * 3 kW

[0223] Curve 330 shows the position of the maximum of characteristic curves 310 to 328, which follows Wien's law. It was found that for all characteristic curves 310 to 328, the polyimide substrate is virtually transparent to IR radiation, particularly in the wavelength ranges of the maxima of characteristic curves 310 to 328, and exhibited an extinction of less than 0.4.

[0224] Here, extinction is defined as the ratio of outgoing to transmitted IR radiation of a wavelength or in a wavelength range, as explained above.

[0225] The choice of a polymer substrate with such low adsorption properties for IR radiation in the range of 0.6 to 1.8 pm, ideally in the range of 0.75 to 1.75 pm, has the great advantage that a large group of individual fibers can be annealed as a (dense) bundle, while still exhibiting very homogeneous separation properties with regard to permeance and selectivity. In the present experiments, groups of up to 100 individual fibers were successfully annealed as fiber bundles using IR radiation.

[0226] Figure 12 shows the measured transmittance values ​​comparing an isotropic film and a membrane made of the same polymer substrate, polyimide. The graph is plotted as transmittance in percent [%] (y-axis) against the wavelengths from 900 nm to 4900 nm (x-axis). The membrane proved to be slightly less transparent than the isotropic film, which can be considered an aspect of its heatability using IR radiation.

[0227] Experiment V5 (Fig. 8 and Fig. 9)

[0228] In experiment V5, fiber bundles of two IR emitters with a length of 0.2 rriE and different nominal powers were annealed, with the first IR emitter having a nominal power of 2.1 kW and the second IR emitter having a nominal power of 2.8 kW. The measured values ​​achieved with the first IR emitter are shown as "o" in the graphs, the measured values ​​achieved with the second IR emitter are shown with an "x". The measured permeance (left graph) and selectivity (right graph) are normalized to the permeance and selectivity of a fiber bundle that was annealed with a conventional electric convection oven, whereby the line is defined at the value y = 1. This can also be referred to as the target value or specification. The measurements were taken at IR emitter powers (x-axis) of 0.75 kW to 1.6 kW.

[0229] The absolute energy input during the annealing step at the set power (x-axis) of the respective IR emitter is shown as a numerical value next to the respective measured value (symbol). The different energy inputs in kJ thus result from the duration of the annealing step.

[0230] The measurement points shown correspond to the values ​​in Table 2, where column 1 shows the number of individual fibers in the bundle, column 2 the nominal power of the IR emitters, column 4 the absolute energy input, column 5 the normalized O2 permeance, column 6 the normalized O2 / N2 selectivity and columns 7 and 8 the corresponding standard deviations from the values ​​in columns 5 and 6, respectively.

[0231] Table 2: Test results of test V5

[0232] (Legend of Table 2: nom. - nominal, SD - standard deviation; IR-E - IR emitter; norm. - standardized)

[0233] The two partial representations I. and II. differ in that in partial representation I. a fiber bundle of 10 individual fibers was annealed by the two IR emitters and in partial representation II. fiber bundles of 80 individual fibers were annealed in the two IR emitters.

[0234] The normalized permeance of 6 indicates complete gas permeability to the gas mixture (left graph), as is the case with an unannealed hollow fiber. This value correlates with a normalized selectivity of 0.4, which does not separate the gas mixture into the individual gases O2 and N2.

[0235] The graph in Figure 11 summarizes the results of Figure 10 for fiber bundles of 10 and 80 individual fibers for permeance and selectivity in one graph each. Thus, the measurement points in the left graphs I and II of Figure 10 correspond to those in the left graph of Figure 11. Analogously, the measurement points in the right graphs I and II of Figure 10 correspond to those in the right graph of Figure 11. The graphs in Figure 11 provide a simple logarithmic plot (y-axis).

[0236] For the fiber bundles consisting of 10 individual fibers, the corresponding measured values ​​are shown as small circles in the graphs of Figure 11; for the fiber bundles with 80 individual fibers, the corresponding measured values ​​are shown as "x" in the graphs of Figure 11. Despite the 8-fold number of individual fibers, a higher permeance and only a slightly reduced selectivity were observed, based on an exponential, mathematical relationship between the measured values, as indicated by the dashed lines.

[0237] To demonstrate the homogeneity of gas permeation across the entire bundle of 80 fibers, the standard deviation of O2 permeance and O2 / N2 selectivity was measured by dividing the 80-fiber bundle from one annealing test into 10 sub-bundles, each of which was measured separately for permeation. The average standard deviation for permeance was 25% and for selectivity, 7%. Considering the numerous experimental error sources (high proportion of manual work), these values ​​were an indicator of good homogeneity of the individual fibers of an 80-fiber bundle during annealing using IR radiation.

[0238] All fiber bundles with 80 individual fibers met the (usual) specification for intended gas separation and were comparable and in some cases better than the fiber bundles commercially annealed in an electric convection oven.

[0239] Increasing the number of treated individual fibers by eight times did not lead to a linear relationship with the gas separation properties of the fiber bundle. A relationship between logarithmic permeance and selectivity and the performance of the IR emitters was observed (exponential relationship). Overall, the eight-fold increase in the number of fibers under the test conditions led to

[0240] - a slight decrease in O2 / N2 selectivity with increasing power of the IR emitter and

[0241] - a 1.3-fold increase in permeance with increasing power of the IR emitter, both plotted and evaluated in the semi-logarithmic system.

[0242] Surprisingly, with increasing power, the permeance of the fibers decreases more rapidly in fiber bundles consisting of 10 individual fibers (lower dashed line) than in fiber bundles with 80 individual fibers (upper dashed line), as shown in the left graph. Furthermore, it was surprisingly observed that with increasing energy input, a nearly identical increase in selectivity is observed for both fiber bundles.

[0243] Without being bound to a specific interpretation, the reasons for the high, homogeneous separation performance of the hollow fiber annealed according to the invention are seen as follows: i) The high transparency (low extinction) of the fibers towards IR radiation, especially at the wavelength in the maximum power range of the IR emitter (< 5% extinction (IR absorption)), ii) refraction of the IR radiation and relatively uniform scattering and transmission to neighboring fibers (radiation homogenization), and iii) strong convective energy transport in the annealing furnace through the gas flow (convective-thermal homogenization in the annealing furnace). ...

[0244] List of reference symbols

[0245] 100 system

[0246] 102 polymer solution

[0247] 104 Process medium

[0248] 106 spinning unit

[0249] 108 Leadership role

[0250] 109 Alley routing (y-direction)

[0251] 110 fiber

[0252] 112 fiber bundles, fiber sub-bundles

[0253] 120 coating stations (PDMS)

[0254] 130 Control and regulation unit

[0255] 132 data line

[0256] 134 Control (Power)

[0257] 140 Feeding and feeding unit, also supply unit

[0258] 142 tanks

[0259] 144 Inert gas supply

[0260] 146 Pump (unit)

[0261] 150 Fixing unit

[0262] 160 washing units

[0263] 170 post-treatment unit

[0264] 180 assembly units

[0265] 182 Fixing station, banding station

[0266] 184 Cutting station

[0267] 186 Lifting unit (xyz unit)

[0268] 188 transport element, conveyor belt

[0269] 190 unloading station

[0270] 200 thermal treatment units

[0271] 210 Drying station

[0272] 214 Gas discharge

[0273] 220 dehumidification station

[0274] 222 nozzle unit

[0275] 224 Gas supply line

[0276] 226 compressors

[0277] 230 fiber storage

[0278] 232 Deflection elements (dynamic, movable) 240 Exchange unit

[0279] 250 tempering station

[0280] (thermal treatment station 3)

[0281] 251 Tempering furnace

[0282] 252 IR emitters

[0283] 254 Reflector

[0284] 256 housings

[0285] 258 Fixation

[0286] 259 Weight

[0287] 260 grouping station

[0288] 270 Gas supply unit

[0289] 272 Gas discharge unit

[0290] 274 Gas filter unit

[0291] 280 funding

[0292] 300 heating steps

[0293] 302 Ramp-Up

[0294] 304 Performance step

[0295] 306 Cooling step

[0296] 310 - 328 characteristic curve

[0297] 330 Curve of the maxima from 310 - 328

[0298] 350 IR absorption curve

[0299] 400 warm-up phase

[0300] 402 Rump-Up Phase

[0301] 404 Tempering phase

[0302] 406 Cooling phase

[0303] A Main conveying direction

[0304] B Forwarding direction

[0305] C supply line

[0306] F1, F2 conveyor line

Claims

Claims 1. A plant (100) for producing a hollow fiber, in particular a spun hollow fiber, from at least one polymer solution (102), comprising a control and regulation unit (130), a media supply and feed unit (140), a spinning unit (106) for forming the fiber (110), wherein downstream of the spinning unit (106) for treating the fiber (110), at least the following plant units are included in the stated sequence: a. an exchange unit for solvent exchange (240), in particular comprising a (first) fixing unit (150) into which the fiber can be introduced or passed directly after the spinning unit (106), and advantageously comprising at least one washing unit (160) downstream of the fixing unit (150), b. at least one post-treatment unit (170), comprising a thermal treatment unit (200) with at least one thermal treatment station, characterized in thatthat downstream of the exchange unit (240), at least one thermal treatment station of the thermal treatment unit (200) is provided, which is designed as a tempering station (250) comprising at least one tempering furnace (251), and wherein the at least one tempering furnace (251) comprises at least one infrared emitter (IR emitter) (252), wherein the fiber (110) can be at least temporarily received and / or passed through the at least one tempering furnace (251) comprising the IR emitter (252), and wherein the tempering furnace (251) is designed to heat the at least temporarily received and / or passed-through fiber (110) for a defined time to a temperature that is below the glass softening temperature (TG), in particular also in the range i) up to 80 °C below the glass softening temperature (TG), and / or ii) greater than 250 °C.

2. Plant according to claim 1, characterized in that i) the tempering chamber of the tempering furnace (251) is open to the atmosphere during normal operation and / or ii) has at least one gas inlet opening for the controlled (active) introduction of gas into the tempering chamber.

3. Plant according to one of the preceding claims, characterized in that the tempering furnace (251) is designed to heat the at least temporarily received and / or passable fiber (110) i) for a defined time up to a limit temperature which is max. 1 °C to 4 °C below the glass softening temperature (TG).

4. Plant according to one of the preceding claims, characterized in that the thermal treatment unit (200) comprises, as a further thermal treatment station, a drying station (210) upstream of the tempering station (250), through which the individual fibers (110) can be passed on the strand, wherein the drying station (210) comprises a. - at least one drying element and / or b. - an inlet and outlet line for a drying medium, such as in particular a heated gas, and with which the interior of the drying station (210) can be heated to at least a temperature of above 30 °C, advantageously above 40 °C and ideally above 50 °C, wherein the interior can be heated to a maximum of 200 °C.

5. System according to one of the preceding device claims, characterized in that the thermal treatment unit (200) comprises, as a further thermal treatment station upstream of the tempering station (250), a dehumidification station (220), in which the individual fibers (110) are guided through at a distance from one another transversely to the axial direction (fiber longitudinal axis (AF)), which comprises at least one nozzle element (222) which is directed onto the path of at least one individual fiber (110), and by means of which a gas jet can be guided onto at least one individual fiber (110), in particular a group of individual fibers (110).

6. System according to one of the preceding device claims, characterized in that i) a grouping station (260) of the grouping unit is arranged upstream of the tempering station (250), ii) the tempering station (250) is arranged within a grouping unit, and / or iii) between two grouping stations (260) of a grouping unit, wherein at least one grouping means is provided in the grouping station (260), by means of which at least one group of n individual fibers (110) can be arranged in mutually touching contact as a bundle (112), wherein n is an integer value from 2 to 180, preferably from 20 to 150, ideally from 30 to 120, wherein optionally up to n = 600 is possible.

7. Plant according to one of the preceding device claims, characterized in that the tempering station (250) comprises a ventilation unit or is connected to a ventilation unit and / or the tempering furnace (251) has at least one gas inlet opening, in particular a gas inlet opening for air.

8. System according to one of the preceding device claims, characterized in that the IR emitter (252) has a power related to the emitter length of - has at least 7.5 kW / rriE, advantageously at least 10 kW / rriE and ideally at least 15 kW / rriE and - of max. 100 kW / rriE, advantageously of max. 50 kW / rriE, ideally of max. 35 kW / rriE.

9. System according to one of the preceding device claims, characterized in that the tempering furnace (251) comprising the at least one IR emitter (252) is designed in the manner of a channel or alley, having at least two walls or wall sections parallel to the fiber longitudinal axis (AF).

10. System according to one of the preceding device claims, characterized in that the at least one tempering station (250), comprising the tempering oven (251) with the IR emitter (252), is arranged at one of the following system locations: a. Downstream of the washing unit (160), wherein no (further) thermal treatment station of the thermal treatment unit (200) is arranged upstream of the tempering station (250), b. Downstream of at least one dehumidification station (220) of a thermal treatment unit (200), c. Downstream of at least one drying station, in particular downstream of a drying station which is arranged downstream of a coating station or application unit.

11. Plant according to one of the preceding device claims, characterized in that a finishing unit (180) is arranged downstream of the tempering station (250).

12. Plant according to one of the preceding device claims, characterized in that a fiber storage (230) is arranged upstream of the tempering station (250).

13. Plant according to one of the preceding device claims, characterized in that it is designed to continuously transport the fiber (110) from the spinning unit (106) to at least the exit of the tempering station (250).

14. Plant according to one of the preceding device claims, characterized in that the post-treatment unit (170) comprises a coating station (120) and / or a discharge station (190).

15. A method for producing a fiber (110) spun from a polymer solution (102), in particular for the parallel production of m (individual) fibers (110), comprising the following steps: - spinning step of the fiber (110) from the polymer solution (102), - exchange step for exchanging a solvent, wherein the exchange step may comprise at least one fixing step with a liquid fixing medium and / or at least one washing step in / with a washing medium, in particular in a basin with a washing medium, - drying step comprising a tempering step in which the fiber (110) is heated to a temperature below the glass softening temperature (TG), characterized in that the fiber (110) is heated in the tempering step by means of at least one continuously operated IR emitter (252).

16. The method according to claim 14, characterized in that in the tempering step, the heating of the fiber (110) is tempered by heating the fiber (110) for a defined time to a temperature which is below the glass softening temperature (TG), and i) is in the range up to 80 °C below the glass softening temperature (TG), and / or ii) is in the range of greater than 250 °C.

17. Method according to one of the preceding method claims, characterized in that in the tempering step the fiber (110) is heated for a defined time i) to a limit temperature which is max. 1 °C, in particular max. 4 °C below the glass softening temperature (TG) and / or ii) is heated to a limit temperature in the range from 70 °C to 1 °C below the glass softening temperature (TG) and / or ii) is heated to a temperature in the range from greater than 280 °C to 450 °C and below the glass softening temperature (TG).

18. Method according to one of the preceding method claims, characterized in that during the annealing step the fiber (110) is irradiated by means of the IR emitter (252) with an IR radiation power related to the emitter length of - at least 5 kW / rriE, preferably at least 7.5 kW / rriE and ideally at least 10 kW / rriE, and where - the IR radiation power is max. 100 kW / rriE, advantageously max. 50 kW / rriE and ideally max. 35 kW / rriE.

19. Method according to one of the preceding method claims, characterized in that the fiber (110) is produced on a system (100) which is designed according to at least one of the preceding device claims 1 to 14.

20. Method according to one of the preceding method claims, characterized in that the tempering step consists of at least two sub-steps: - a heating step in which the IR radiation power is in the range of 5 to 25% of the maximum IR radiation power, advantageously 7.5 to 15%, ideally 10% and - a power step, with a maximum IR radiation power of 100 kW / rriE, advantageously of max. 50 kW / rriE and ideally of max. 35 kW / rriE.

21. Method according to one of the preceding method claims, characterized in that at least one group of m individual fibers (110) are formed (aligned) before the annealing step in a grouping step to form at least one (partial) bundle (112) of n = 5 to 180 individual fibers (110) and subsequently annealed as a bundle (112), wherein either - n is smaller than m, so that two or more (partial) bundles (112) are formed or - n is equal to m, so that only one bundle (112) is formed.

22. Method according to one of the preceding method claims, characterized in that the fiber (110) is continuously transported from the spinning unit (106) to at least the exit of the tempering station (250).

23. Process according to one of the preceding process claims, characterized in that the annealing time is in the range of 0.1 to 60 s, preferably 0.5 to 30 s, ideally 1 to 20 s.

24. Method according to one of the preceding method claims, characterized in that the tempering furnace i) is open to the atmosphere, in particular has an inlet and / or outlet opening for the fiber and a passive air introduction takes place with the conveyed fiber into the tempering furnace and / or ii) comprises or is connectable to a ventilation station, via which a gas mixture, in particular air, N2 and / or CO2, is introduced into the interior of the tempering furnace.

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