Installation and method for producing a fiber from a polymer solution

Abstract

The invention relates to an installation for producing a hollow fiber, said hollow fiber being formed from at least one polymer solution. The installation comprises a control and regulating unit, a supply and feed unit for media, and a spinning unit for forming the fiber, and at least the following installation units are provided, in the specified sequence, downstream of the spinning unit in order to treat the fiber: - a solvent-exchange unit which can comprise in particular a (first) fixing unit or which can be substantially formed therefrom and into which or through which the fiber can be introduced or passed immediately after the spinning unit, a washing unit being advantageously provided downstream of the fixing unit, and - 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 comprising at least one temperature-control furnace; the at least one temperature-control furnace comprises at least one heating element; the fiber can be at least temporarily received in and / or guided through the at least one temperature-control furnace; and the temperature-control furnace is designed to heat the at least temporarily received and / or guided fiber for a defined time (temperature-control time) in particular up to a temperature which lies below the glass softening temperature (TG) and i) in the range below the glass softening temperature (TG) up to 80 °C and / or ii) in the range above 250 °C The invention further relates to a corresponding method for producing a fiber.

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] WO 2014 / 202324 A1 proposes, for further improvement, drying hollow fibers preferably at a temperature in the range of 50 to 100 °C and then annealing them. The drying process is intended to 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.%. The background to this is that an excessively high residual content of water and solvent during the annealing of entire membrane bundles leads to the membranes sticking together. Furthermore, excess water can lead to hydrolysis and thus to 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] WO 2014 / 202324 A1 proposes 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 with an oxygen content of less than 0.5 vol.%, 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 an improved plant and an improved process for a fluid separation membrane than known plants and processes, with constant or increased 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 media supply and feed unit, and a spinning unit for forming the fiber. Downstream of the spinning unit, at least the following system units are included for treating the fiber in the sequence mentioned: a) an exchange unit for solvent exchange, which in particular comprises a (first) fixing unit or can be essentially formed therefrom, into which the fiber can be introduced or passed directly 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 heating element and / or an inlet for a heating medium, wherein the fiber can be at least temporarily received and / or passed through the at least one tempering furnace, wherein the tempering furnace is designed to heat the at least temporarily received and / or passed through fiber for a defined time (tempering time) up to a (limit) temperature (tempering 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) ii) in the range of greater than 250 °C and below the glass softening temperature (TG).

[0011] Here, "annealing time" refers to the duration or residence time of the conveyed or temporarily resting fiber in the annealing furnace and within the annealing temperature ranges specified therein. "Limit temperature," "annealing temperature," or "temperature in the annealing chamber" are used synonymously unless otherwise stated. Here, the "interior of the annealing furnace" refers to the space in which the fiber to be annealed is arranged or guided, also called the "annealing chamber," and is exposed to the thermal influence of the heating element or heating medium for the purpose of annealing.

[0012] The system is preferably designed for continuous annealing of the fiber in the annealing furnace, in particular for a residence time of the fiber in the annealing furnace of less than 30 minutes, at atmospheric pressure or a pressure slightly higher than atmospheric pressure in the annealing furnace. The system, and in particular the annealing furnace, is advantageously designed such that the residence time of the fiber in the annealing chamber or a heating section corresponding to the annealing chamber is in the range of 0.5 to 180 s, preferably 1.0 to 120 s, particularly preferably 1.0 to 60 s, particularly preferably 1.0 to 30 s, ideally 1.0 to 15 s.

[0013] In this case, the annealing furnace and / or the annealing chamber can be designed free of guide elements that touch the fiber or can have guide elements that touch the fiber, which deflect the fiber axis at least for a partial distance within the annealing furnace and / or the annealing chamber and thus geometrically influence the residence time of the fiber in the annealing chamber.

[0014] There may be an advantage in a system variant if the system and in particular the tempering furnace are designed such that the temperature in the tempering chamber or a heating section corresponding to the tempering chamber is in the range from 300 to 800 °C, preferably in the range from 320 to 780 °C, particularly preferably in the range from 350 to 750 °C, particularly preferably in the range from 380 °C to 700 °C.

[0015] It has been found to be particularly advantageous if the system, the tempering station and / or the tempering oven are designed so that a ratio V1 [s / T] of the residence time [s] of the fiber to the temperature in the tempering chamber [K] in the range of 0.0006 to 0.6 s * K -1 preferably in the range of 0.0006 to 0.43 s * K' 1 , particularly preferably in the range of 0.048 to 0.429 s * K -1 , particularly preferably in the range of 0.176 to 0.429 s * K -1The advantageous ratio V1 was found particularly for the temperature range in the tempering chamber from 300 to 800 °C. It has also been found to be particularly advantageous if the system and / or the tempering furnace are designed so that a ratio V2 [s * m -1 * K -1 ] of residence time [s] to inner diameter of the tempering chamber [m] and temperature in the tempering chamber [K] in the range of 0.001 to 0.545 s * irr 1 * K -1 preferably in the range of 0.043 to 0.39 s * irr 1 * K -1 , particularly preferably in the range from 0.086 to 0.39 s ' rrr 1 * K -1 The advantageous ratio V2 was found particularly for the temperature range in the tempering chamber from 300 to 800 °C.

[0016] The system advantageously comprises pulling devices, particularly downstream of the annealing furnace. The pulling devices, also called "pullies," are particularly designed to exert a tension in mN per individual fiber on the annealing furnace and particularly in the annealing chamber of the annealing furnace in the range of 10 to 500 mN, preferably in the range of 10 to 200 mN, more preferably 10 to 100 mN, more preferably 10 to 50 mN, and more preferably 10 to 30 mN.

[0017] In particular, it is advantageous if the fibers are conveyed through the tempering furnace by the pulling device (pully) with the lowest possible tensile force. "Pulling devices" in this context refer to any drive unit that directly exerts a tensile force in the axial direction of the fiber via a motor drive, such as a winding wheel, a roller, a clamping conveyor belt, etc. In the case of rollers, these are in particular deflection rollers, against whose surface the fiber rests for an angular range, thereby changing the direction of the fiber axis, in particular changing the direction relative to the main conveying direction for a partial distance.

[0018] The heating element can be, for example, a resistance heater, a burner element, or a fluid-conducting heat exchanger, so that the heating element heats the fiber, preferably contactlessly, via a gas atmosphere in the annealing chamber. In this case, a distinction is made between a "heating gas inlet" and a "burner element," whereby in a burner element, the burner exhaust gases are not introduced into the annealing chamber unless otherwise specified.

[0019] In contrast, in this case, "heating gas introduction" means that at least a partial volume flow of a heating gas is introduced into the tempering chamber and flows around the fiber. A heating gas can have a burner and the burner exhaust gas generated there as its source, so that the heating gas is formed at least partially from burner exhaust gas, in particular has a high volume percentage of CO2. In a preferred embodiment, "heating element" does not comprise an IR emitter and "heating medium" does not comprise IR radiation. In this case, "no IR emitter" or "no IR radiation" also means a heater, such as a resistance heater, which emits a design-related portion of IR radiation, although this portion of radiation accounts for no or only a very small portion of the overall heating output, in particular for heating the fiber.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.

[0020] 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 passed-through 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.

[0021] 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.

[0022] 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.

[0023] The annealing station and / or the annealing furnace are thus designed to anneal the fiber using a continuous process for a defined period of time (annealing time). The fiber can also be conveyed within the annealing furnace in a step-by-step process for the actual annealing step, so that the fiber or fiber bundle is temporarily slowed down and / or temporarily stopped. Alternatively or additionally, the pulling device for conveying the fiber in the annealing station and / or the annealing furnace is designed and / or controllable for the continuous process and the control and regulation of the defined period of time (annealing time).

[0024] Advantageously, the tempering station is connectable to or comprises a ventilation unit for operating the tempering furnace and / or the tempering process, wherein preferably the tempering furnace is connectable to the ventilation unit or comprises a ventilation unit. The ventilation unit comprises, in particular, at least a gas supply and at least a gas discharge, wherein, in the simplest case, a gas discharge can be a separate opening in the tempering furnace and / or the supply and / or outlet opening for the fibers. Advantageously, the ventilation unit comprises a pressure sensor for detecting the pressure in one of the supply or discharge lines of the (cooling) gas or for the interior of the tempering furnace. A compressor can be integrated into the gas supply.The fiber feed and / or outlet opening is advantageously dimensioned such that a free flow cross-section for a gas or gas mixture remains adjacent to the fibers, particularly a ring- or frame-shaped flow cross-section encircling the fiber. A particular advantage of the encircling flow cross-section has been observed: a very stable, largely laminar gas flow parallel to the fiber develops in the annealing chamber. This allows for highly reproducible, stable process conditions in the annealing chamber of the annealing furnace.

[0025] The fiber is thus annealed directly or indirectly in the annealing station or annealing furnace. In this context, "direct" means that the fiber is heated via a temperature gradient by a heating element and / or a hot surface, and further convectively by a gas flowing in the annealing chamber. In this context, "indirect" means that heat transfer, such as solid-state radiation, can also reach an individual fiber through neighboring individual fibers via reflectors and / or heated components, walls, and / or wall sections.

[0026] 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 from 80 °C to 1 °C below the glass softening temperature, preferably in the range from 70 °C to 1 °C, particularly preferably in the range from 65 °C to 4 °C below the glass softening temperature. According to the invention, the fibers are annealed in a annealing furnace, whereby the desired high separation properties of the hollow fiber membranes are developed. When using the present invention in a continuous annealing furnace, annealing is to be understood analogously to WO 2014 / 202324 A1, to obtain gas separation membranes that exhibit very high selectivity and also very good permeance by annealing hollow fibers at temperatures close to the glass softening point.

[0027] The glass softening temperature (TG) can be determined using various dynamic differential calorimetry (DSC) methods, particularly according to the DIN 53765 method. The threshold temperature should still be below the decomposition temperature (TD). Thus, analogously to TG, the decomposition temperature (TD) of a fiber and / or fiber material (polymer substrate) can also be used to determine the upper threshold temperature and the threshold temperature range. This depends on whether the effects of decomposition or glass softening occur when the fiber and / or fiber material are heated at different or overlapping temperature ranges. Decomposition can occur, for example, in burning, incineration, cracking, embrittlement, or other destructive effects.

[0028] In the case of a fiber material with a material property of TD < TG, where the degradation is that increased material shrinkage already sets in at TD < TG, especially TD « TG, the limit temperature should be lower than TD in a similar manner. Thus, the system should advantageously be designed to always maintain the distance to TD with the limit temperature, analogous to TG, 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.

[0029] Fiber materials with pronounced degradation at temperatures below and above TD 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).

[0030] This degeneration temperature TD 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).

[0031] In this way, in the case of the polymer materials in question, a fibre temperature of greater than 250 °C, in particular greater than 280 °C, is achieved in the tempering oven, whereby the aforementioned material-dependent distance to TG and / or TD is maintained.

[0032] 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 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 a wet or very moist fiber leads to adverse effects on 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, in particular 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 represents an independent drying process or drying step for the fiber.

[0033] This additional thermal treatment station can advantageously comprise or be connected to an alternative drying agent and alternative heating device. 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.

[0034] The term “tempering station” in the present case should be 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, if applicable the power control unit, ventilation and / or cooling unit with the necessary connections, etc. The system and in particular the tempering furnace is designed to accommodate at least one individual fiber in its interior in a continuous process and to heat this at least temporarily to a temperature below the glass softening temperature TG or the degeneration temperature TD by means of a heating element and / or a heating gas, as described herein. Even if the tempering station is not identical to the tempering furnace, the term “tempering station” is not used herein in certain cases.A distinction is made between tempering station and tempering furnace, whereby the context of the text reveals what is meant. For example, a formulation that “the tempering station comprises a heating element” is to be understood to mean that the heating element is included in the tempering station as part of the tempering furnace.

[0035] Even if the term “heating element” is primarily used below, this does not only refer to a single heating element, but also to a group of heating elements, such as a group of heating coils of an electrical resistance heater and / or a plurality of heating gas inlets into the tempering chamber.

[0036] A system and a corresponding method have been found that make it possible to reduce the annealing times known from the prior art, for example, using a convection oven in batch mode, by a factor of approximately 0.001 or more through the design and continuous operation of the annealing oven. Furthermore, lengthy heating steps could be completely avoided. In particular, a system and a method were found that are designed for continuous operation, in particular for the continuous production of a hollow fiber as a membrane for gas separation.

[0037] In the present context, "polymer solution" means, in addition to the substances mentioned herein as examples, also liquid and / or liquefied polymer melts. "Polymer solution" means, in particular, 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;

[0038] 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.

[0039] The polymer solution may further comprise 2D or 3D fillers that, in terms of size and composition, are suitable 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 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.

[0040] Advantageously, the polymer solution is formed as described in EP 3083761 B1.

[0041] Particularly when fillers are present in the polymer solution, it is advantageous if the number n of individual fibers in a fiber bundle to be tempered is less than 600, and if bundles of individual fibers or smaller sub-bundles of up to a maximum of 180 individual fibers are tempered, preferably up to a maximum of 120 individual fibers, ideally up to a maximum of 100 individual fibers per sub-bundle. Without being limited to one interpretation, fillers can lead to greatly increased heat storage and / or energy reflection, so that the homogeneity of the tempering of the individual fibers in the fiber bundle decreases, in particular central individual fibers arranged in the bundle center are not tempered or are only incompletely tempered.

[0042] 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.

[0043] The individual fibers, which are at least initially spaced apart from one another, are kept apart by comb- or finger-like forming elements of forming units at least along a portion of the system. Typically, the individual fibers are arranged in a line next to one another, i.e., spaced apart from one another in the y-direction. In the annealing furnace, the fibers can be conveyed individually, in partial bundles, or as a single bundle. To form one or more (fiber) bundles, appropriate guide means and / or grouping tools can be provided upstream of the annealing furnace.

[0044] In this context, "fiber(s)" 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.

[0045] The term "bundle", "sub-bundle", "fiber bundle" or "fiber sub-bundle" refers here to an arrangement of a plurality of individual fibers in which the individual fibers are arranged touching one another and, for example, substantially parallel to one another or twisted against one another around a common longitudinal axis. A "bundle", "sub-bundle", "fiber bundle" or "fiber sub-bundle", hereinafter referred to as "bundle" for short, can be held and / or formed by at least one guiding and / or gripping tool, possibly only temporarily formed, unless expressly described otherwise. Furthermore, a "bundle" can be at least temporarily fixed and formed against one another on at least one or two sides by a fixing element, such as a band, lacing, or clamp.

[0046] 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.

[0047] Advantageously, the system comprises a plurality of guide and drive elements along the conveying path of the fiber thread, which may be, for example, guide fingers, guide rollers, guide plates or other suitable elements, wherein the guide and drive elements may be located inside and outside the treatment unit, even inside liquids or a liquid volume.

[0048] The media contained in the media feed and storage unit can

[0049] - include fibre media, namely media and materials from which the fibre itself is formed at least temporarily, and

[0050] - 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] This also applies, for example, to the fiber medium as feed for the spinning step, which is called “casting solution” in WO 2014 / 202324 A1.

[0056] 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.

[0057] In an advantageous embodiment of the system, it can be provided that the thermal treatment unit comprises a drying station as a thermal treatment station through which the individual fibers are passed, wherein the drying station

[0058] - at least one drying element and / or

[0059] - 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.

[0060] 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.

[0061] 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 determined essentially or exclusively by the proportions of water and the respective solvent. Advantageously, the fibers are passed through this treatment station in strand form, i.e., uncut, and fed downstream, particularly directly downstream, to the annealing station.

[0062] 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 (flushing 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 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 the fluid-dynamic removal of the adhering external liquid 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.

[0063] 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 within a grouping unit, and / or iii) the tempering station 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 contact with one another. In this case, n is fundamentally unlimited, and values ​​up to n = 600 individual fibers are possible, wherein n is advantageously an integer value from 2 to 180, preferably from 20 to 150, ideally from 30 to 120.

[0064] 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 from the total number of conveyed individual fibers two or more sub-bundles are formed and downstream in a grouping station the (final) bundle with the total number of individual fibers is formed. Advantageously, the tempering station with the tempering 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 tempering of all individual fibers can take place. By treating the two or more sub-bundles in parallel in the tempering station or tempering furnace, the latter can be designed to be smaller.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 (ambient air).

[0065] 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. Thus, a ventilation unit can comprise or be connected to a gas conditioning unit. The gas conditioning unit advantageously comprises 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 thermally or passively driven. "Passively driven" means that the gas is at least partially entrained by the conveyed fiber.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.

[0066] Surprisingly, it has been found that the gas atmosphere, i.e., the gas composition and, in particular, low O2 concentrations, in the annealing furnace has almost no influence on the quality of the fiber, especially not on the selectivity and / or 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.

[0067] Advantageously, in one embodiment of the system, it can be provided that the ventilation unit comprises at least one gas conditioning unit for the supplied cooling gas and / or is connected thereto.

[0068] Even if the term "cooling gas" is generally used for the supplied gas in the present case, and this indicates an essential function or purpose of the gas supplied into the interior of the tempering furnace, this should not be understood in a restrictive manner. Cooling gas also refers to the gas or gas component that flows at least partially, in particular completely through the interior of the tempering furnace, in particular at least partially through the space between the wall elements, (lateral) reflectors, spaces between a heating element, etc., in that, during normal operation, the fibers to be tempered are also arranged so that the cooling gas can flow around these fibers at least partially. If a heat exchanger is used in the tempering furnace, this can preferably be arranged as a double wall, wall element or self-supporting heat exchanger inside the tempering furnace in order to maintain a constant temperature and / or prevent a limit temperature from being exceeded, i.e.This prevents overheating of individual components of the tempering furnace. In particular, cooling gas can be used to create a defined, constant gas atmosphere at the entrance to the tempering chamber and thus also within the tempering chamber, even in conditions that fluctuate significantly throughout the year and / or day.

[0069] The gas conditioning unit can form a single structural unit or consist of multiple elements, such as, in particular, a drying unit for setting a defined humidity (H2O) in the cooling gas, a filter unit, in particular a HEPA filter, for setting a defined particle content or a largely particle-free state in the cooling gas. Furthermore or alternatively, the gas conditioning unit can comprise or be formed from a gas separation unit or module, by means of which O2 depletion, in particular from ambient air, can be initiated. The gas separation unit can, in particular, comprise at least one hollow fiber filter module, which is identical or analogous to the filter modules and / or filter materials described herein.

[0070] The ventilation unit, the cooling unit, and / or the gas conditioning unit can comprise at least one flow control unit, in particular a flow control unit that can be controlled and / or regulated by the control and regulation unit. Alternatively or additionally, the ventilation unit, the cooling unit, and / or the gas conditioning unit can be connected or can be connected to such a flow control unit.

[0071] The gas supply via a ventilation station into the tempering furnace and the tempering chamber, especially in addition to a heating element such as a resistance heater, has a beneficial effect on the controllability and regulation of the atmosphere in the tempering chamber. The gas supply line can comprise one or more inlet openings and / or channels into the tempering furnace. Furthermore, the tempering furnace can comprise a gas outlet, in particular from the at least one tempering chamber, for the controlled and / or regulated discharge of the hot gas mixture. The gas outlet can comprise one or more outlet openings from the tempering furnace.

[0072] 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.

[0073] In an advantageous embodiment, it can thus 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, in particular for the controlled introduction of an O2-containing gas mixture.

[0074] In particular, heating gas from an external heating gas source can be fed into the tempering chamber via at least one gas inlet opening.

[0075] Here, "open to the atmosphere" means that even in a tempering furnace that is mechanically closed or closable, at least one passage opening exists during intended, closed operation through which a fiber can be conveyed during operation of the tempering furnace. Advantageously, a tempering furnace has two passage openings: an inlet and an outlet for the fiber.

[0076] 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.

[0077] 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 surprisingly been shown that the passive entry of ambient air has no adverse effect on the fiber quality, in particular not on the selectivity and / or permeance.

[0078] In a further advantageous embodiment, the ventilation station is alternatively or additionally designed to introduce or pass an inert gas into the tempering furnace, in particular nitrogen (N2). Advantageously, the ventilation station is designed to create a low-oxygen atmosphere in the tempering furnace; this can in particular consist in the O2 content being reduced, but being equal to or greater than 5.0 mol%, in particular equal to or greater than 10 mol%, preferably equal to or greater than 15 mol%. However, it has proven particularly preferred if ambient air is used as the cooling gas, in particular ambient air conditioned by means of a gas conditioning unit is used, which in particular has not been depleted of O2 and / or has been modified with regard to the gas proportions N2, O2, CO2 or noble gas, i.e. enriched or depleted.

[0079] The gas flow within the annealing furnace, and especially in the annealing chamber, is not limited and can be directed 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.

[0080] In order to shorten reaction times when it is necessary to lower the temperature in the tempering chamber, the tempering furnace in an advantageous embodiment has a cooling unit, in particular a cooling unit which is operated with a fluid, such as water.

[0081] In a further advantageous embodiment of the system, the heating element of the tempering furnace, such as a resistance heater, can have a power based on the length (m) of the tempering furnace or the resistance heater in meters of at least 7.5 kW / m, advantageously of at least 10.0 kW / m and ideally of at least 15 kW / m. Advantageously, the power of the resistance heater is max. 100 kW / m, preferably max. 50 kW / m, and ideally of max. 35 kW / m. In particular, heating elements that can be operated at a power of 8 to 17.5 kW / m can temper a polymeric hollow fiber or a bundle of up to 100 individual fibers within a time period of less than 15 s, ideally less than 10 s, and specification-compliant permeances and selectivities can be achieved.

[0082] In addition to at least one heating element, the tempering furnace may have one or more reflectors in the interior, wherein a reflector may be attached to a wall or it may at least form part of an inner wall or an inner wall section of the tempering furnace.

[0083] In a further advantageous embodiment, it can be provided that the tempering furnace is constructed in two or more parts and for this purpose has at least two interior spaces (tempering spaces) or sections that are shielded from one another. Such a tempering furnace is designed to heat the fiber in a first interior space or section for a first treatment duration at a first power level in at least one heating step and to temper the fiber downstream in a further interior space or section for a further treatment duration at a further power level that is different from the first in at least one power level. Here, “shielded” means that at least one separating and / or deflecting element is provided, in particular a separating element with a suitable small passage opening. This ensures that the energy from the further interior space or section does not reach the subsequent interior space or sections.The separating element can also be a lock element or intermediate space without a heater, a heating element and / or heating gas inlet, in particular without an IR radiation emitter.

[0084] In a further advantageous embodiment, at least one fiber storage unit can be provided before and / or after the tempering station, particularly before the tempering station, so that the fiber or bundle can be conveyed within the tempering 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 tempering period. Ideally, the fiber storage unit is motor-driven and / or controllable; particularly advantageously, the fiber storage unit is integrated into an adjacent treatment unit.

[0085] Advantageously, the system provides for the tempering furnace to be designed in the shape of a channel or lane 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), as it exists during normal operation of the system. The walls or wall sections can be covered with the aforementioned reflectors, heating elements, heat exchangers or can be at least partially formed from them. Thus, a fiber is guided uncut on a strand through the tempering station and tempered during transport in the direction of the fiber axis. According to this embodiment, the tempering furnace can therefore have an inlet opening and an outlet opening into which the fiber is continuously fed and discharged. To improve the controllability of the tempering step and the tempering furnace, at least one guide and deflection can be included, in particularA movable deflection device, by means of which the fiber is deflected at least once in the area and / or within the tempering furnace. It is particularly advantageous if the guide and deflection device is adjustable, in particular motor-adjustable, so that the residence time of a fiber or a fiber section in the tempering furnace, and in particular in the area of ​​the heating element and / or the heating gas inlet / throughput, can be controlled as needed. Residence time in the tempering furnace and tempering time are also used synonymously in this context.

[0086] In a highly economical design of the annealing station, it is designed as a lane or channel with walls aligned parallel to the transport direction, particularly the longitudinal fiber axis. In principle, the position and number of heating elements and / or heating gases relative to the conveyed fiber are not restricted, provided the expert observes the quality-relevant parameters, such as the power of the heating elements, the duration of exposure to the fiber, and the uniformity of the energy input to the fiber.

[0087] 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.

[0088] 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.

[0089] The at least one tempering station with the at least one tempering furnace can advantageously be arranged at one of the following plant locations:

[0090] Downstream of the washing unit, whereby 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,

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] Alternatively, the assembly unit is arranged upstream of the tempering station, wherein the tempering station comprises at least one tempering furnace.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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. In the annealing step, the desired separation properties of the hollow fiber are developed overall by means of energy input up to the limit or annealing temperature. Ideally, each coating station is followed by a drying station.

[0103] The hollow fibers used for gas separation can be of two basic types: i) ISA membranes

[0104] 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 separation properties are formed in the annealing step. Here, a first separating layer is formed during the exchange (displacement) of the solvent in the fixing station of the exchange unit, since a compacted layer similar to 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 of the spinneret from the fixing bath. In a further advantageous embodiment, it can be provided that the separating layer or the fiber with the said separating layer is coated with at least one polymer material that is different from the base fiber (coating step), in particular with the polymer material polydimethylsiloxane (PDMS).ii) Asymmetric composite membrane (AK membrane) comprising a base fiber as a basic or support structure and an applied outer separation layer, which may include at least one further coating layer.

[0105] 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, for example, aromatic polyimide, aromatic polyetherimide, aromatic polypolyamides, polyarylene ethers, aromatic polybenzimidazoles and / or mixtures thereof, wherein at least one 2D or 3D filler can be included, such as, for example, zeolites, MOF particles (metal-organic framework materials), mexenes (MXenes) and / or graphenes or ii) be formed essentially from an inorganic or metal-organic material, such as, for example,Zeolites, MOF particles (Metal-Organic Framework Materials), mexenes (MXenes) and / or graphenes, whereby suitable binders may be provided.

[0106] 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.

[0107] 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.

[0108] According to the invention, the two aforementioned basic types of hollow fiber membrane are finally tempered in the tempering furnace, whereby the desired high separation properties are formed.

[0109] 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.

[0110] 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:

[0111] - spinning step of the fiber from the polymer solution,

[0112] - 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,

[0113] - at least one drying step, comprising a tempering step in which the fiber is heated to a temperature below the glass softening temperature (TG) 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 by a heating element and / or a heating gas.

[0114] In this case, in the tempering step, the fiber is continuously heated by means of at least one heating element (252) and / or a heating medium in a tempering furnace to a temperature which is 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 and below the glass softening temperature (TG).

[0115] The temperature in the annealing furnace can be higher than TG and must be determined depending on the geometry of the annealing furnace, especially the interior, and the residence time of the fiber in the annealing furnace.

[0116] In this process, the fiber is continuously heated in the annealing furnace using a heating element and / or a heating medium in a surrounding gas atmosphere. Furthermore, a cooling gas can be passively introduced or actively introduced, which at least partially creates the gas atmosphere during the annealing step.

[0117] The manufacturing process is preferably a process for continuously annealing the fiber in a annealing furnace, in particular for a fiber residence time in the annealing furnace of less than 30 minutes, at atmospheric pressure or at a pressure slightly elevated relative to atmospheric pressure. In an advantageous process variant, the fiber residence time in the annealing chamber or a heating section corresponding to the annealing chamber is 0.5 to 180 s, preferably 1.0 to 120 s, particularly preferably 1.0 to 60 s, particularly preferably 1.0 to 30 s, ideally 1.0 to 15 s.

[0118] In this case, the fiber can advantageously be transported without contact in the annealing chamber, or the fiber can be deflected by contacting guide elements along the fiber axis for at least a partial distance within the annealing furnace and / or the annealing chamber, so that the fiber's residence time in the annealing chamber is geometrically influenced by deflection. One process variant can be advantageous if the temperature in the annealing chamber or a heating section corresponding to the annealing chamber is in the range of 300 to 800 °C, preferably in the range of 320 to 780 °C, particularly preferably in the range of 350 to 750 °C, particularly preferably in the range of 380 °C to 700 °C.

[0119] It has been found to be particularly advantageous if, in a process variant, the ratio V1 [s / T] of the residence time [s] of the fiber in the annealing chamber to the temperature in the annealing chamber [K] is in the range from 0.0006 to 0.6 s / K, preferably in the range from 0.0006 to 0.43 s / K, particularly preferably in the range from 0.048 to 0.429 s / K, particularly preferably in the range from 0.176 to 0.429 s / K. The advantageous ratio V1 was found in particular for the temperature range in the annealing chamber from 300 to 800 °C.

[0120] It has further been found to be particularly advantageous if, according to a process variant, a ratio V2 [s / m*K] of the residence time [s] of the fiber in the annealing chamber to the inner diameter of the annealing chamber [m] and the temperature in the annealing chamber [K] is given, which is in the range from 0.001 to 0.545 s / m*K, preferably in the range from 0.043 to 0.39 s / m*K, particularly preferably in the range from 0.086 to 0.39 s / m*K. The advantageous ratio V2 was found in particular for the temperature range in the annealing chamber from 300 to 800 °C.

[0121] Advantageously, the method provides that a tensile force in mN per individual fiber is exerted on the fiber, which is in the range from 10 to 500 mN, preferably in the range from 10 to 200 mN, particularly preferably from 10 to 100 mN, particularly preferably from 10 to 50 mN, particularly preferably from 10 to 30 mN.

[0122] Advantageously, the method provides that n individual fibers are annealed in parallel in the annealing step, where n =< 600, preferably n =< 180, particularly preferably n =< 120, ideally n <= 100. Furthermore, it is advantageous if n individual fibers are annealed in parallel in the annealing step, where n >= 2, preferably n >= 10, particularly preferably n >= 20, ideally n >= 40. This results in an advantageous range of 2 to 600 individual fibers which are annealed in parallel in the annealing step as, for example, a single fiber bundle or corresponding smaller fiber bundles.

[0123] In a variant of the method, it may be advantageous if the annealing time is in the range of 0.5 to 60 s, preferably 1 to 30 s, ideally 1 to 20 s. If a multi-stage annealing is carried out, or a annealing in which a preliminary heating step is carried out, followed by at least one power step in which the fiber is annealed at maximum power, the aforementioned annealing times refer to the power step or the sum of the power steps. In a further improvement, which in particular results in better controllability of the continuous process, it can be provided that a cooling gas is supplied which cools at least a part of the tempering furnace and / or the fiber in the tempering step, wherein the cooling gas flows through the tempering furnace (251) at a gas exchange frequency (AF) of 0.15 per minute to 30 per minute, cooling gas and wherein the heating energy introduced into the tempering furnace (251) is =< 50 kJ / m.

[0124] Advantageously, the cooling gas at the inlet has an inlet temperature that is 5 to 50 °C below the outlet temperature at the tempering furnace, preferably 5 to 30 °C, ideally 5 to 15 °C.

[0125] The "exchange frequency" or synonymously "gas exchange frequency" refers here to the volume of the interior of the tempering furnace, in particular the portion of the interior in which the fiber is accommodated and the heating element or the heating gas acts thermally on the fiber, in particular acts directly thermally on the fiber, wherein this interior and / or portion of the interior of the tempering furnace is flowed through by the cooling gas.

[0126] Overall, it was observed that targeted (cooling) gas flow and guidance are crucial for the uniformity of fiber quality, particularly for shaded fibers, and for energy distribution in the annealing furnace. Furthermore, it was surprisingly found that, with regard to fiber selectivity and permeability, there is a correlation between the exchange frequency and the supplied energy. It was discovered that higher exchange frequencies result in improved permeability with constant or essentially constant selectivity. Furthermore, lower exchange frequencies resulted in improved selectivities with slightly reduced permeabilities. Thus, this provides a lesson that a plant operator can control and regulate the exchange frequencies and / or the energy input depending on the specifications of the fiber to be produced.

[0127] 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 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). It is particularly advantageous here if the distance of max. 1 °C to 4 °C from the glass softening temperature (TG) is maintained in order not to damage the structure, in particular the desired porosity, of the hollow fiber.To avoid fiber damage due to fluctuations in the heating temperature, it may be preferable to provide a maximum distance of 1.5 °C, 2 °C, 2.5 °C, 3 °C, or 3.5 °C from the TG instead of the aforementioned maximum distance of 1 °C. The respective maximum temperature distance from the TG can be specified depending on the respective fiber material and the system and / or process.

[0128] 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).

[0129] It is particularly advantageous if the method for producing a tempered fiber is carried out using a system configured according to at least one of the embodiments and variants described herein. It has proven particularly advantageous if the tempering chamber of the tempering furnace is designed as a channel or alley, and the fiber is guided contact-free within the tempering chamber. This means that the fiber is not contacted by deflection elements on one or more sides during the tempering step. In this way, particularly uniform membrane properties can be achieved.

[0130] It may be an advantage in a variant of the method that a group of m individual fibers are formed into at least one bundle of n = 5 to 600 individual fibers in a grouping step before the annealing step and subsequently annealed as a bundle, wherein either

[0131] - n is smaller than m, so that two or more sub-bundles are formed or

[0132] - n is equal to m, so that only one bundle is formed.

[0133] With a very large total number m of individual fibers, it can be advantageous to form sub-bundles of n individual fibers to reduce shadowing and insulation between the fibers in the annealing chamber. The sub-bundles can be annealed in a common annealing chamber in the annealing furnace. Alternatively or additionally, sub-bundles can be annealed in a second annealing furnace and / or separate annealing chamber.

[0134] One advantage of a variant of the method can be that the fiber is transported continuously from the spinning unit at least to the exit of the tempering station, in particular is transported uncut. In a further preferred embodiment of the method, it can be provided that the tempering step takes place at a pressure which is in the range of max. + 2 bar to atmospheric pressure, preferably + 1 bar, preferably + 0.5 bar or equal to atmospheric pressure. This ensures in particular that a defined flow direction always prevails within the tempering chamber in the tempering furnace and in particular that no external air is sucked in. The flow direction of the cooling gas within the tempering chamber is not restricted, although it has proven advantageous to flow against the fibers in countercurrent for at least part of the length or section.This has the advantage that the heat (energy) is transported from the fiber sections exposed to the heating element for the longest time to the fiber sections exposed for the shorter time and thus cooler.

[0135] 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, from 2 to n = 600, using a tempering furnace and the heating element therein, 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 packed more densely, and the risk of fiber breakage in individual fibers is reduced during shrinkage processes.

[0136] In a preferred process variant, the fiber can be treated during the annealing step using the heating element with a power of at least 5.0 kW / m, preferably at least 7.5 kW / m, and ideally at least 10 kW / m, based on the length of the heating element in meters (m). It may also be advantageous if the heating power is a maximum of 100 kW / m, advantageously a maximum of 50 kW / m, and ideally a maximum of 35 kW / m.

[0137] 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.

[0138] Advantageously, the annealing step can take place in an inert or largely inert atmosphere in which the O2 content in the annealing furnace is below 1,000 ppm. Surprisingly, however, it has proven technically feasible and economically very advantageous to adjust the atmosphere in the annealing furnace to a gas mixture of equal to or greater than 5.0 mol%, in particular equal to or greater than 10 mol%, preferably equal to or greater than 15 mol%. It has proven particularly preferred and surprising to carry out the annealing step in ambient air, in particular conditioned ambient air. The remaining gas components of the cooling gas are advantageously N2, in particular the remaining gas components are above 95 mol% N2. Thus, ambient air with ~21 mol% O2 can be supplied.

[0139] Here, “conditioned ambient air” means that ambient air or any other O2-containing gas mixture is filtered in a suitable manner before being introduced into the tempering furnace and / or the tempering step, in particular with regard to particle concentration, and / or is conditioned with regard to humidity and / or temperature.

[0140] The energy for tempering is advantageously introduced by a heating element, such as a resistance heater, a burner, a heat exchanger, etc., at least on one side in the direction of the fiber or fiber bundle in the tempering furnace and advantageously distributed by convection and / or reflection from at least one inner wall and / or at least one reflector within the tempering furnace. Alternatively or additionally, the energy can be introduced directly into the interior via a heating medium, such as a heating gas. The heating gas can be generated indirectly via a heat exchanger or in a combustor as combustion exhaust gas. The combustion exhaust gas can in particular originate from the combustion of a carbon-containing substance, in particular a carbon-containing gas or gas mixture. The carbon-containing gas or gas mixture can advantageously be or comprise methane, ethane, propane or butane.

[0141] An outstanding effect was surprisingly discovered: the total annealing time using a continuous volume flow of a heating gas and / or a continuously operating heating element, such as a resistance heater, for a bundle of up to 80 individual fibers requires only, for example, 0.1% of the annealing time compared to a conventional, batch-operated annealing furnace, such as an electric forced-air or convection furnace. 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.

[0142] To limit diffusion processes in the fiber containing residues of solvent or exchange medium, it may be advantageous not to perform the energy input during annealing in a single step. Thus, a further process embodiment may consist of the annealing step consisting of at least two sub-steps, namely

[0143] 1) at least one heating step in which the power is in the range of 5 to 25% of the maximum power, advantageously 7.5 to 15%, ideally 10%; and

[0144] 2) at least one power step in which the defined maximum power for tempering is introduced into the tempering furnace.

[0145] In the case of such a multi-stage annealing step, the annealing time is essentially calculated based on the power step or the sum of the power steps. The duration of the heating step is advantageously 1 / 6 to 1 / 3 of the power step, with the power step advantageously being in the range of approximately 0.1 to 60 s, preferably 0.5 to 30 s, ideally 1 to 20 s.

[0146] Although a distinction is made here between "annealing step" and "power step," "annealing step" is sometimes used synonymously with the "power step," in which the maximum power is applied by the heating element and / or the heating medium to the annealing furnace. There is an advantage in terms of simple and efficient process control if the heating step is carried out by cooling with a cooling gas over at least a portion of the annealing furnace, in particular by cooling with an incoming gas stream.

[0147] In a further embodiment of the process, it may be advantageous for the fiber to be conveyed during at least part of the heating and / or power annealing step. Advantageously, the fiber is conveyed throughout the entire annealing step.

[0148] 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 or a gas mixture, in particular air, N2 and / or CO2, is introduced into the interior (tempering chamber) of the tempering furnace.

[0149] In alternative embodiments of the method, as explained above for the tempering furnace, gas is guided through at least one lock.

[0150] 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, which can be passively drawn out while hot.

[0151] It is advantageous if the gas or gas mixture, especially air, which is passively or actively introduced with the fiber flows parallel to the conveying direction of the fiber, in particular flows in the same direction as the fiber. This avoids vibrations and thus mechanical stress on the fiber, although the flow direction of the gas or gas mixture is generally possible. However, it has proven particularly advantageous if the cooler, incoming gas flows in the same direction into the tempering furnace, since this makes the temperature transition for the cold, incoming fiber less rapid, similar to multi-stage tempering. In a simple but very economical process variant, no lock chamber is provided. In an improvement to this embodiment, a lock chamber can be provided, in particular a heatable lock chamber, via which an initial heating of the fiber and shielding of the interior of the tempering furnace takes place.Preferably, a heating gas is introduced into the lock chamber to limit the ingress of cold or strongly temperature-fluctuating ambient air and / or to reduce the thermal stress on the fiber at the outlet. The heating gas can be a gas mixture, such as air or an O2-containing gas mixture. Alternatively or additionally, the gas (mixture) can comprise at least one inert gas, such as nitrogen (N2) or carbon dioxide (CO2). Alternatively, the lock chamber can comprise a heating element to achieve the same effect.

[0152] To improve the controllability of the manufacturing process, a further advantageous embodiment provides for a gas supply, particularly into the at least one interior space (annealing chamber) in addition to a heating element arranged and / or acting there. A gas mixture, particularly air, is introduced into the interior space of the annealing furnace by means of a connected or connectable ventilation station, for example, a compressor (active). The gas supply can be provided via one or more inlet openings in the annealing furnace, with a gas outlet provided.

[0153] 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 annealing furnace components, without interrupting the process. This is particularly advantageous when the heating element, such as a resistance heater, and / or an internal, fluid-conducting chamber are separated from the annealing chamber and the fiber conveyed therein by a heavy-duty wall element, thus resulting in significant system inertia and / or longer dead times until control changes to lower temperatures (cooling effects) take effect on the conveyed fiber.

[0154] Although the system and method are primarily described for continuous tempering, the present invention is not limited to this. The tempering furnace can also be a batch unit, so that the fibers, a fiber bundle, or a group of fiber bundles are tempered in batch mode using at least one heating element and / or the heating gas.

[0155] Alternatively, the fibers can advantageously be cut to a desired length before annealing and / or advantageously fixed at least temporarily as (partial) bundles, analogous to the treatment units of the systems described herein. With this stepwise or batchwise annealing, it is generally advantageous to anneal the individual fibers or fiber bundles while hanging or held vertically in the axial direction, so that the individual fibers remain largely aligned parallel to one another.

[0156] The inventive solution is described in detail below using exemplary embodiments. It shows:

[0157] Fig. 1 the system in a first embodiment,

[0158] Fig. 2 the system in a second embodiment,

[0159] Fig. 3 shows the plant in a third embodiment, Fig. 4 shows the plant in a fourth embodiment, Fig. 5 shows the plant in a fifth embodiment, Fig. 6 shows two embodiments for the transport of the fiber in the tempering station, Fig. 7 shows the test setup as a schematic representation and Fig. 8 shows another graph comparing the residence times in the tempering oven.

[0160] 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 presentation and feed 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 tempering station 250 according to the invention, as well as 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.Other elements for the power and data lines, as well as the automation of the system, are generally known to those skilled in the art and are not further described here. The storage and supply unit 140 is also only shown in outline and includes tanks 142 or a tank storage facility for media, in particular for the polymer solution 102 from which the fiber 110 is formed and process media 104, a pump (unit) 146, and an (inert) gas supply. These are connected to the spinning unit 106 in a media-conducting manner.

[0161] 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. 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, wherein the individual fibers 110 are oriented in the y-direction at a defined spacing from one another by means of a comb-like or multi-finger-shaped channel guide 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.

[0162] 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.

[0163] The tempering station 250 connected in the main conveying direction A comprises a tempering furnace 251 as a central element with a heating element 252, wherein the heating element 252 is designed as an electrical resistance heater and is arranged in the 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 (residence time) of approximately 2 to 20 seconds, wherein the tempering time can be divided into two or more sub-steps, such as a heating step and a power step.

[0164] The tempering station 250 or the tempering furnace 251 is connected to a ventilation unit 290, which comprises a gas supply unit 270 and a gas discharge unit 272, wherein a compressor 226 and a gas filter unit 274 are parts of the gas discharge unit 272. In the example shown, the gas supply and discharge lines 270, 272 are part of the ventilation unit 290, wherein the gas supply unit 270 comprises a gas source and / or is connected to supply and / or intake elements for atmospheric outside air. Furthermore, a flow control unit 136 is connected to the gas supply unit 270, which in the example shown is a controllable gas valve and / or throttle. The flow control unit 136 is connected to the central control and regulation unit 130 via the data line 132 and can be centrally controlled.In an alternative embodiment not shown, the flow control unit 136 is a (only) locally adjustable and / or controllable gas valve or throttle. The ventilation unit 290 further comprises a gas conditioning unit 298, by means of which ambient air is drawn in, the cooling gas flow is dehumidified, and filtered using a HEPA filter.

[0165] By means of the compressor 226, a complete flow through the filter 274 can be ensured, particularly at higher flow resistances, by a downstream filter 274, because the inlet and outlet of the fiber bundle 112 may not be sealed from the annealing chamber. This is intended to prevent excessive heating and / or detrimental escape of gases from the annealing chamber. In a simplified embodiment (not shown), no compressor and / or filter is provided in the gas discharge unit 272.

[0166] At the discharge end of the tempering station 250 opposite the input side, a conveyor 280 is arranged, which is designed as a forming and conveying unit and which forwards the fiber bundle 112 in compacted formation to the finishing 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 Fig. 3, 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.

[0167] 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 several 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 off from the (bundle) strand to a desired length, which is then temporarily stored or stacked as a finished bundle 112.

[0168] Subsequently, the finished bundles 112 are discharged from the finishing unit 180 in the forwarding direction B by means of the transport means 188. The system 100 shown in Figure 2 differs from the system shown in Figure 1 in particular in that no drying station 210 is provided; instead, 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. In the example shown in Figure 2, the tempering oven 251 has a resistance heater 253 as heating element 252, opposite which a reflector 254 is arranged in the interior of the tempering oven 251.The tempering station 250 is connected downstream to 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 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.

[0169] 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.

[0170] Compaction takes place 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 a tempering station 250 with a resistance heater 256 because it has surprisingly been found that with continuous tempering it is 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 without or after only slight drying by means of, for example, resistance heating.

[0171] The elimination of the drying station 210 and the associated lines and units results in significant energy savings and a significant reduction in the space required by the systems. Figure 3 shows a very schematic representation of the systems 100 and the fiber 110, as well as the bundle 112 on its way 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.In contrast to this, 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 furnace 251 of the annealing station 250 downstream of the annealing unit 180 by means of a resistance heater (not shown).

[0172] In the embodiment of Figure 4, in contrast to the system variant of Figure 3, the tempering furnace 251 of the tempering 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 through the tempering furnace 251 and tempered. In particular, the transport speed and / or the length of the tempering furnace 251 are dimensioned and / or coordinated such that the required residence time (tempering time) of the individual fibers 110 or the at least one fiber bundle 112 in the area of ​​influence of the resistance heater (not shown) can be maintained.

[0173] 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.

[0174] 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. 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.

[0175] 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.

[0176] 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.

[0177] 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 resistance heating (not shown) can be maintained.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] Even though the annealing furnace 251 is always depicted in a horizontal (lying) orientation, in which the transport direction of the fiber 110 or the fiber bundle 112 is 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.

[0182] The laboratory and experimental setup shown in Figure 7 and the graphs shown in Figure 8 are described and discussed below together with the discussion of the experimental results.

[0183] Experimental setup

[0184] The tests were carried out using a tempering station 250, as shown in Figure 7, which is designed analogously to Figure 3 and is essentially a detailed representation of Figure 3. The tempering station 250 comprised, as its central element, a tempering furnace 251 having a closed housing 256 comprising two half-shells which, in the closed state shown, form the tempering chamber 254 as an interior space. A through-opening 258 is arranged on each of the end faces. Resistance heaters 252, outlined by a grid-like pattern, are integrated into the housing 256 in both half-shells. A channel-like interior space is formed inside the tempering furnace 251 as the tempering chamber 254, through which the fiber bundle 112, coming from the drying station 180, is conveyed in the tempering step. The elements for bundling the individual fibers 110 into a fiber bundle 112 are not shown.

[0185] Temperature measurement is performed via a temperature sensor 294. The temperature sensor 294, the resistance heater 252, and the fiber drive (not shown) are connected to the control and regulation unit 130 via data lines. The tests were conducted in continuous operation. The annealing furnace 251 was thermally insulated on the outer shell but not actively cooled.

[0186] Downstream of the annealing furnace 251, the bundle 112 was cut to length and measured for selectivity and permeance.

[0187] 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.

[0188] Permeability and permeance

[0189] The gas permeabilities are measured in Barrer (10' 1 °-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 m -2 fr 1 bear 1 .

[0190] permeability

[0191] 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.

[0192] The permeability of the polymer (substrate) can be calculated according to the following formula: P Permeability in Barrer (1O -10 cm 3 (STP) cm) / (cm 2 s cmHg)

[0193] [barrer] = 1 ,333*1017 * [Nm 3 *m / (m 2 *s*Pa)] with STP (Standard Temperature and Pressure): is 0°C, 101325 Pa

[0194] Vdead volume of the permeate side in cm 3

[0195] MWGAS Molar mass of the gas in g mol -1

[0196] I Thickness of the foil in cm p Density of the gas in g cm -3

[0197] R gas constant in cm 3 cmHg K -1 mole -1

[0198] T Temperature in Kelvin

[0199] A Area of ​​the film in cm 2

[0200] 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

[0201] 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:

[0202] P / l permeance in GPU (Gas permeation units. 10 -6 cm 3 cm -2 s -1 cmHg -1 )

[0203] Q Gas flow of the permeate side in cm 3 (STP) / s

[0204] R gas constant in cm 3 cmHg K -1 mole -1

[0205] T Temperature in Kelvin

[0206] A Outer surface of the hollow fiber in cm 2

[0207] 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

[0208] The selectivities of different gas pairs are pure gas selectivities. The selectivity between two gases is calculated from the quotient of their permeabilities:

[0209] S = Pi / P2

[0210] S ideal gas selectivity

[0211] Pi permeability or permeance of the gas 1

[0212] P2Permeability or permeance of gas 2

[0213] Try

[0214] Tests 1 and 2 were conducted in the test setup described above, as shown in Figure 7. Reference fibers from a batch process and an unannealed fiber were compared with fibers continuously annealed according to the invention. The reference fibers were annealed in an electric convection oven under vacuum for 6 hours as a fiber bundle of 80 individual fibers (VOa), a fiber bundle of 80 unannealed individual fibers, and continuously conveyed and annealed fiber bundles of the same number of individual fibers with different residence times in the continuously operated annealing oven. The residence times of the fiber or a discrete fiber section in the annealing oven were derived from the different conveying speeds of the fiber.

[0215] Try

[0216] Experiments V1 and V2 investigated the influence of the residence time of the conveyed polyimide fiber at a higher constant temperature in the annealing furnace than in Experiment 1. Two bundles of polyimide fibers were compared at different temperatures.

[0217] Table 1 shows the measured values ​​from the two tests V1 and V2. The fibers were spun from the polymer material polyimide, and in all tests, the core temperature of the annealing furnace was constant at approximately 450 °C. The core temperature was measured in the center of the furnace, with the temperature gradient along the longitudinal axis in the interior (annealing chamber) remaining negligible due to the introduction of ambient air.

[0218] A Nabertherm® RSRC 120-1000 / 13 continuous tube furnace was used as the annealing furnace (251). It features a continuous working tube heated by an external resistance heater in a heating section. A metal tube served as the working tube. The metal working tube was not heated at the inlet and outlet sides of the heating section and was cooled by atmosphere. The continuous furnace was operated in a non-inclined, horizontal orientation. The working tube represents the annealing chamber in the heating section.

[0219] The fiber bundle of at least 30 individual fibers was fed into one end of the working tube (input side), passed through the heated area (heating section) and was led out at the other end (output side) under tensile stress.

[0220] The technical data of the continuous tube furnace included the following:

[0221] - maximum temperature of 1300°C in the interior (tempering room)

[0222] - Rated power max. 13.7 kW - 14.4 kW

[0223] - stainless steel working tube open on both sides

[0224] - Thermocouple type S, freely radiating heating elements on the working tube

[0225] - Outer furnace casing made of stainless steel structural sheets, perforated

[0226] - Hinged, hood-like furnace housing; especially inner furnace hood with integrated resistance heating

[0227] Integrated control and switching unit

[0228] There was an option for three-zone control of the resistance heating, with the same temperature always being maintained in all three zones. Due to its design, the continuous tube furnace had an adjustable speed for the mounted working tube between 0.28 and 6 revolutions per minute, which was not used in the tests.

[0229] Due to the design, the heating section is divided into three zones, with the resistance heating coils embedded in an inner furnace hood positioned opposite the working tube in each of the three zones, directly impacting it. Furthermore, the continuous furnace featured thermally insulated inlet and outlet nozzles on this inner furnace hood. No resistance heating coils were located on the outside of these nozzles, meaning they were neither directly heated nor cooled.

[0230] To determine the fiber's residence time in the annealing chamber (heating section), the inlet and outlet nozzles were also considered part of the heating section due to the heat conduction of the metallic working tube. The length of the heating section thus included the insulated inlet and outlet nozzles and corresponds to the length of the annealing chamber of the annealing furnace.

[0231] The inner furnace hood was thermally insulated from the environment on the shell side and had a round passage opening on the flat end faces on the inlet and outlet sides, which essentially corresponded to the inner diameter of the working tube and was 110 mm, through which the respective fiber bundle consisting of n individual fibers was passed.

[0232] Before the annealing step, the individual fibers were continuously dried upstream of the annealing furnace at a temperature of approximately 80 °C. Cooling gas was introduced into the annealing furnace as ambient air in an unregulated (passive) manner together with the conveyed fiber bundle and exited the outlet opening there unregulated and heated. The fiber bundle comprised 30 individual fibers (n = 30). Downstream, the fiber bundle was cut and measured for O2 permeance and O2 / N2 selectivity as described herein. The hot exhaust air exiting the outlet opening was extracted and removed via an exhaust hood in the interior of the test facility. The temperature in the annealing chamber of the continuous furnace was approximately 450 °C.

[0233] Table 1: Results of Experiment 01

[0234] The corresponding graph is shown in Figure 8. The y-axis shows the normalized O2 / N2 selectivity, and the x-axis the normalized O2 permeance, which was normalized based on the reference fiber (V2_0b). The solid trend line serves primarily as a visual guide and does not represent a mathematical relationship in the strict sense. The different symbols have the meanings indicated in the graph legend. A measurement point for the unannealed fiber is not shown in the graph in Figure 8.

[0235] On the one hand, it was surprisingly shown that, despite the very short annealing times of less than 10 s, selectivities and permeances could be achieved that are in the range of the conventionally produced reference fiber. The annealing time of the reference fiber was approximately 6 hours in the electric convection oven, thus reducing the residence time by several hours. With regard to selectivities, improvements of up to 26% were even achieved, with only minor losses in permeance. It was particularly surprising that a dependence of selectivity and / or permeance on the residence time was evident, so that selectivity and permeance can be described as a function of the residence time in the annealing oven.

[0236] It was particularly surprising that a dependence of selectivity and / or permeance on the residence time and / or temperature in the annealing chamber was evident, so that selectivity and permeance can be described as a function of the residence time in the annealing furnace. It has thus been shown that, depending on the desired specification, a desired optimum in permeance and selectivity can be achieved by adjusting the process parameters residence time and / or temperature.

[0237] A continuous gas flow in the conveying direction through the annealing furnace was observed, which was detectable due to the hot gases escaping at the fiber outlet. In this operating mode of the annealing furnace, with only passively introduced gas (in this case, ambient air), a largely laminar flow in the conveying direction through the annealing chamber is assumed.

[0238] 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.

[0239] This result is particularly surprising because the prior art, such as WO 2014 / 202324 A1 or WO 2011 / 009919 A1, always requires an inert atmosphere during the annealing step. It has now been demonstrated that, in the case of continuous, very short-term annealing with high energy inputs, a pure N2 atmosphere or an atmosphere severely depleted of O2 is not required to produce highly permeable and highly selective gas separation membranes. Furthermore, it was found that the slow heating of the fibers in the annealing step of 0.1 to 10 °C / min (end of page 10) recommended in WO 2014 / 202324 A1 can be significantly reduced without any disadvantages regarding the selectivity and permeance of the fiber.

[0240] Reference symbol

[0241] 100 system

[0242] 102 polymer solution

[0243] 104 Process medium

[0244] 106 spinning unit

[0245] 108 Leadership role

[0246] 109 Alley routing (y-direction)

[0247] 110 fiber

[0248] 112 fiber bundles, fiber sub-bundles

[0249] 120 coating stations (PDMS)

[0250] 130 Control and regulation unit

[0251] 132 data line

[0252] 134 Control (Power)

[0253] 136 Flow control (unit)

[0254] 140 Feeding and feeding unit, also supply unit

[0255] 142 tanks

[0256] 144 Inert gas supply

[0257] 146 Pump (unit)

[0258] 150 Fixing unit

[0259] 160 washing units

[0260] 170 post-treatment unit

[0261] 180 assembly units

[0262] 182 Fixing station, banding station

[0263] 184 Cutting station

[0264] 186 Lifting unit (xyz unit)

[0265] 188 transport element, conveyor belt

[0266] 190 unloading station

[0267] 200 thermal treatment units

[0268] 210 Drying station

[0269] 212 Gas supply line

[0270] 214 Gas discharge

[0271] 216 heat exchangers

[0272] 220 dehumidification station

[0273] 222 nozzle unit

[0274] 224 Gas supply line

[0275] 226 Compressor 230 Fiber storage

[0276] 232 deflection elements (dyn., movable)

[0277] 240 replacement unit

[0278] 250 tempering station

[0279] (thermal treatment station 3)

[0280] 251 Tempering furnace

[0281] 252 heating element, e.g.

[0282] 254 Temper room (interior)

[0283] 256 housings

[0284] 258 passage opening

[0285] 260 grouping station

[0286] 270 Gas supply unit

[0287] 272 Gas discharge unit

[0288] 274 Gas filter unit

[0289] 280 funding

[0290] 290 ventilation unit

[0291] 292 heat exchangers

[0292] 294 Unit of measurement (temperature)

[0293] 296 Measuring unit (flow)

[0294] 298 Gas conditioning unit

[0295] 300 heating steps

[0296] 302 Ramp-Up

[0297] 304 Performance step

[0298] 306 Cooling step

[0299] A Main conveying direction

[0300] B Forwarding direction

[0301] C supply line

[0302] 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 heating element (252) and / or an inlet for a heating medium, wherein the fiber (110) can be at least temporarily received and / or passed through the at least one tempering furnace (251), 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 up to a limit temperature which is below the glass softening temperature (TG) in the range of: i) to 80 °C below the glass softening temperature (TG) and / or ii) greater than 250 °C, and wherein the tempering station (250) and / or the tempering furnace (251) is particularly designed to continuously temper the fiber (110)., 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 (290) or is connected to a ventilation unit (290) and / or the tempering furnace (251) has at least one gas inlet opening, in particular a gas inlet opening for air.

8. Installation according to one of the preceding device claims, characterized in that the heating element (252) and / or the heating gas, in particular the resistance heating, has a power of - has at least 7.5 kW / m, advantageously at least 10 kW / m and ideally at least 15 kW / m and - of max. 100 kW / m, advantageously of max. 50 kW / m, ideally of max. 35 kW / m.

9. Plant according to one of the preceding device claims, characterized in that the tempering furnace (251) is designed in the form of a tube, channel or alley, having at least two walls or wall sections, in particular parallel to the fiber longitudinal axis (AF).

10. Plant according to one of the preceding device claims, characterized in that the at least one tempering station (250), comprising the tempering oven (251), is arranged at one of the following plant 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. Installation according to one of the preceding device claims, characterized in that it is designed to guide the fiber (110) from the spinning unit (106) to at least to the exit of the tempering station (250) continuously.

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) which is 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 continuously in the tempering step by means of at least one heating element (252) and / or a heating medium in a tempering furnace (251) to a temperature which is 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 and below the glass softening temperature (TG).

16. The method according to claim 15, characterized in that in the tempering step n individual fibers are tempered in parallel, where n =< 600, preferably n =< 180, particularly preferably n =< 120, ideally n <= 100.

17. The method according to claim 16, characterized in that in the tempering step n individual fibers are tempered in parallel, where n >= 2, preferably n >= 10, particularly preferably n >= 20, ideally n >= 40.

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

19. Method according to one of the preceding method claims, characterized in that a cooling gas is supplied which cools at least a part of the tempering furnace (251) in the tempering step, wherein the cooling gas flows through the tempering furnace (251) with a gas exchange frequency (AF) of 0.15 per minute up to 30 per minute, Cooling gas and the heating energy introduced into the tempering furnace (251) is =< 50 kJ / m.

20. 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 iii) is heated to a temperature in the range greater than 280 °C to 450 °C and below the glass softening temperature (TG). 21 . Method according to one of the preceding method claims, characterized in that the tempering step is carried out at a pressure which is in the range of max. + 2 bar to atmospheric pressure, preferably max. + 1 bar, preferably max. + 0.5 bar, ideally equal to or substantially equal to atmospheric pressure.

22. Method according to one of the preceding method claims, characterized in that the cooling gas supplied to the tempering furnace (250) in the tempering step is oxygen (O2) in a concentration of equal to or greater than 5.0 mol%, in particular equal to or greater than 10 mol%, preferably equal to or greater than 15 mol%, in particular ambient air, with ~21 mol%.

23. one of the preceding method claims, characterized in that during the annealing step the fiber (110) is heated by means of the heating element (253) and / or the heating medium with respect to the length of the heating element with a power of - at least 5.0 kW / m, preferably at least 7.5 kW / m and ideally at least 10 kW / m, and where - the line is max. 100 kW / m, advantageously max. 50 kW / m and ideally max. 35 kW / m.

24. 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.

25. 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 bundle (112) of n = 5 to 600 individual fibers (110) and subsequently annealed as a bundle (112), wherein either - n is smaller than m, so that two or more sub-bundles (112) are formed or - n is equal to m, so that only one bundle (112) is formed.

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

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