Fiber dissolving liquid adjustment system

Abstract

To reuse a resin fiber as a raw material for a new resin fiber.SOLUTION: There is provided a fiber dissolution liquid adjustment system, comprising: a raw liquid tank for storing a liquid in which a resin fiber is dissolved in an organic solvent; a storage tank to which the liquid may be transferred from the raw liquid tank; an adjustment tank to which the liquid may be transferred from the raw liquid tank and the storage tank; a distribution transfer line for transferring the liquid from the raw liquid tank to the storage tank or the adjustment tank; a raw liquid measurement unit for measuring a moisture content of the liquid stored in the raw liquid tank; an adjustment transfer line for transferring the liquid from the storage tank to the adjustment tank; a discharge line for discharging the liquid from the adjustment tank; an adjustment measurement unit for measuring a moisture content of the liquid stored in the adjustment tank; a distribution control unit that determines whether the liquid is to be transferred from the raw liquid tank to the storage tank or the adjustment tank through the distribution transfer line, depending on a magnitude relationship between a measurement value of the raw liquid measuring unit and a predetermined distribution reference value; and an adjustment control unit for adjusting an amount of the liquid transferred from the storage tank to the adjustment tank via the adjustment transfer line so that a measurement value of the adjustment measurement unit is adjusted within a predetermined reference range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fiber dissolving solution adjusting system. [Background technology]

[0002] Spinning equipment is widely used to produce resin fibers by extruding a resin solution (spinning solution) into a coagulation tank that stores a coagulation solution containing water as a main component. It has also been proposed to recover and dissolve resin fibers that have been manufactured into products in a solvent, thereby reusing them as raw materials for new resin fibers. For example, Patent Document 1 describes dissolving acrylic fibers in a solvent and reusing them as a spinning solution, and describes that if the moisture content of the recycled acrylic fibers exceeds 15%, they become less soluble in the solvent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-121922 Summary of the Invention [Problem to be solved by the invention]

[0004] In a spinning facility that extrudes a resin solution into a coagulation tank, resin fibers that cannot be used as a final product may be generated, for example, at the start and end of production. It has been considered to dissolve such resin fibers that cannot be used as a final product in a solvent and reuse them as raw materials for new resin fibers. However, the resin fibers recovered from the coagulation tank may contain a relatively large amount of water, making it difficult to adjust the moisture content of the solution when dissolved in a solvent. Furthermore, depending on the material of the resin fiber, its solubility in the solvent may be even lower.

[0005] In view of the above circumstances, an object of the present invention is to provide a fiber dissolved solution preparation system that can reuse resin fibers as raw materials for new resin fibers. [Means for solving the problem]

[0006] The present inventors conducted detailed studies on the solubility of resin fibers and discovered that, while it is common for resin fibers extruded into a coagulation tank to be coated with an oil before being stretched or heat-treated in a spinning facility, the oil coating the resin fibers reduces the solubility of the resin fibers. In other words, resin fibers before being oil-coated can dissolve in a solvent at a relatively high water content. Conversely, it was confirmed that resin fibers recovered from a spinning facility after being oil-coated have a higher amount of oil attached than resin fibers from used clothing, etc., and therefore have particularly poor solubility. Furthermore, the present inventors' research has revealed that the solubility of oil-coated resin fibers can be improved by deoiling them. Based on these research results, the present inventors have invented a fiber dissolution preparation system that allows resin fibers recovered from a spinning facility to be reused as a spinning solution.

[0007] (1) A fiber dissolving liquid preparation system according to one aspect of the present invention includes a raw liquid tank for storing a liquid in which resin fibers are dissolved in an organic solvent; a storage tank to which liquid can be transferred from the raw liquid tank; an adjustment tank to which liquid can be transferred from the raw liquid tank and the storage tank; a distribution transfer line for selectively transferring liquid from the raw liquid tank to either the storage tank or the adjustment tank; a raw liquid measuring unit for measuring the moisture content of the liquid stored in the raw liquid tank; an adjustment transfer line for transferring liquid from the storage tank to the adjustment tank; a discharge line for discharging liquid from the adjustment tank; a distribution control unit for determining whether the distribution transfer line should transfer the liquid from the raw liquid tank to the storage tank or the adjustment tank based on the relative magnitude of the moisture content measured by the raw liquid measuring unit and a predetermined distribution reference value; and an adjustment control unit for adjusting the amount of liquid transferred from the storage tank to the adjustment tank via the adjustment transfer line so that the moisture content measured by the adjustment measurement unit is within a predetermined reference range.

[0008] (2) In the fiber dissolving solution preparation system of (1) above, the distribution reference value may be a value within the reference range.

[0009] (3) In the fiber dissolving liquid preparation system of (1) or (2) above, the distribution control unit may cause the distribution transfer line to transfer the liquid from the raw liquid tank to the storage tank when the moisture content measured by the raw liquid measurement unit is equal to or greater than the distribution reference value, and may cause the distribution transfer line to transfer the liquid from the raw liquid tank to the adjustment tank when the moisture content measured by the raw liquid measurement unit is less than the distribution reference value.

[0010] (4) The fiber dissolving liquid adjustment system described in (3) above further includes a water injection line for injecting water into the adjustment tank and a liquid volume measuring unit for measuring the amount of liquid stored in the storage tank, and the adjustment control unit may stop the transfer of liquid through the adjustment transfer line and inject water into the adjustment tank through the water injection line when the amount of liquid stored measured by the liquid volume measuring unit is equal to or less than a predetermined lower limit liquid volume.

[0011] (5) In the fiber dissolving liquid preparation system according to any one of (1) to (4) above, the lower limit of the reference range may be equal to or greater than the average moisture content of the liquid supplied to the raw liquid tank. [Effects of the Invention]

[0012] According to the present invention, resin fibers recovered from a spinning facility can be reused as a spinning solution. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing the configuration of a fiber dissolving solution preparation system according to one embodiment of the present invention. [Figure 2] 2 is a flowchart showing the procedure for preparing a fiber dissolving solution in the fiber dissolving solution preparation system of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, hatching and component reference numerals may be omitted. In such cases, reference should be made to other drawings. Furthermore, the dimensions of various components in the drawings have been adjusted for clarity.

[0015] 1 is a schematic diagram showing the configuration of a fiber dissolving solution preparation system 1 according to one embodiment of the present invention. The fiber dissolving solution preparation system 1 includes a stock solution tank 11, a storage tank 12, an adjustment tank 13, a distribution and transfer line 21, an adjustment and transfer line 22, a discharge line 23, a water injection line 24, a stock solution measurement unit 31, an adjustment and measurement unit 32, a liquid volume measurement unit 33, and a control device 40.

[0016] The fiber solution preparation system 1 can be used to adjust the moisture content of a liquid (fiber solution) in which resin fibers are dissolved in an organic solvent to within a predetermined standard range and supply the liquid to spinning equipment through a discharge line 23, thereby allowing the liquid to be used as part of the spinning solution. Examples of materials for the resin fibers include acrylic resin and modacrylic resin. Examples of organic solvents include polar solvents such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and dimethylacetamide (DMAC).

[0017] The lower limit of the standard range is preferably equal to or greater than the average moisture content of the liquid supplied to the liquid source tank 11 so that the moisture content of the liquid finally discharged from the fiber dissolution liquid preparation system 1 falls within the standard range depending on the amount of water supplied from the water injection line 24. On the other hand, the upper limit of the standard range of moisture content can be set so that a spinning solution that can be spun in the spinning equipment can be prepared.

[0018] The stock solution tank 11 is supplied with a liquid in which resin fibers are dissolved in an organic solvent and stores the supplied liquid. The liquid supplied to the stock solution tank 11 is expected to have a relatively large fluctuation in moisture content. As a specific example, the stock solution tank 11 may be randomly supplied with a liquid with a relatively high moisture content obtained by recovering resin fibers before they are coated with an oil agent in a spinning facility and dissolving them in an organic solvent, and a liquid with a relatively low moisture content obtained by recovering resin fibers after they are coated with an oil agent in a spinning facility and then subjecting them to a deoiling treatment and dissolving them in an organic solvent. Such random supply of liquids can be achieved by using a single batch-type dissolution tank to perform both a process of dissolving resin fibers before they are coated with an oil agent and a process of dissolving resin fibers that have been subjected to a deoiling treatment. The stock solution tank 11 may also serve as a dissolution tank.

[0019] The storage tank 12 receives the liquid transferred from the raw liquid tank 11 and stores the transferred liquid. As will be described in detail later, a liquid having a moisture content equal to or greater than a predetermined distribution reference value is introduced into the storage tank 12. The storage tank 12 may have an agitator 121 that agitates and homogenizes the stored liquid. Homogenizing the liquid stored in the storage tank 12 improves the accuracy of controlling the moisture content of the liquid discharged from the discharge line 23. The agitator 121 may be one that rotates a stirring blade within the liquid, or one that circulates the liquid to homogenize it.

[0020] The adjustment tank 13 receives liquid transferred from the concentrate tank 11 and the storage tank 12 and stores the transferred liquid. The adjustment tank 13 mixes the liquid supplied directly from the concentrate tank 11, the liquid supplied from the storage tank 12, and water supplied from the water injection line 24 to adjust the moisture content of the liquid to within a standard range. For this reason, the adjustment tank 13 preferably has an agitator 131 that agitates and homogenizes the stored liquid. The agitator 131 may be one that rotates a stirring blade within the liquid, or one that circulates the liquid to homogenize it.

[0021] The distribution transfer line 21 selectively transfers liquid from the concentrate tank 11 to either the storage tank 12 or the adjustment tank 13. For this reason, the distribution transfer line 21 may be configured to include a distribution transfer pump 211 and a switching valve 212. Note that if the concentrate tank 11 is placed at a higher position than the storage tank 12 and the adjustment tank 13, the distribution transfer pump 211 may be omitted. Furthermore, the distribution transfer line 21 may have separate flow paths for transferring liquid from the concentrate tank 11 to the storage tank 12 and for transferring liquid from the concentrate tank 11 to the adjustment tank 13.

[0022] The adjustment transfer line 22 transfers the liquid from the storage tank 12 to the adjustment tank 13. For this reason, the adjustment transfer line 22 may be configured to include an adjustment transfer pump 221. Moreover, the adjustment transfer line 22 may be configured to further include an adjustment valve 222 so as to adjust the amount of liquid transferred to the adjustment tank 13. When the storage tank 12 is placed at a higher position than the adjustment tank 13, an on-off valve may be provided instead of the adjustment transfer pump 221. Moreover, instead of the adjustment valve 222, a rotation speed control means such as an inverter that adjusts the rotation speed of the adjustment transfer pump 221 may be provided.

[0023] The discharge line 23 discharges the liquid from the adjustment tank 13. For this reason, the discharge line 23 may be configured to have a discharge pump 231. If the liquid can be transferred from the adjustment tank 13 to the next equipment by a head, an on-off valve may be provided instead of the discharge pump 231.

[0024] The water injection line 24 injects water into the adjustment tank 13. The water injection line 24 may be configured to have an adjustment valve 241 for adjusting the amount of water injected.

[0025] The concentrate measuring unit 31 measures the moisture content of the liquid stored in the concentrate tank 11. The concentrate measuring unit 31 can be disposed near the connection position of the concentrate tank 11 with the distribution transfer line 21, or on the distribution transfer line 21. The concentrate measuring unit 31 can be configured to measure the sound velocity and specific gravity of the liquid, and calculate the moisture content of the liquid from the measured sound velocity and specific gravity. The sound velocity can be measured by vibrating the liquid using an ultrasonic oscillator.

[0026] The adjusting and measuring unit 32 measures the moisture content of the liquid stored in the adjusting tank 13. The adjusting and measuring unit 32 can be disposed near the connection position of the discharge line 23 of the adjusting tank 13 or in the discharge line 23. The configuration of the adjusting and measuring unit 32 can be the same as that of the undiluted solution measuring unit 31.

[0027] The liquid volume measuring unit 33 measures the amount of liquid stored in the storage tank 12. The liquid volume measuring unit 33 may be composed of a level sensor that detects the height of the liquid surface, one or more switches that detect when the height of the liquid surface has reached a certain height, etc.

[0028] The control device 40 controls the sorting and transfer line 21, the conditioning and transfer line 22, the discharge line 23, and the water injection line 24. The control device 40 may be configured with a dedicated circuit, or may be configured with a computer device that executes an appropriate control program. The control device 40 has a sorting control unit 41 that controls the sorting and transfer line 21 based on the moisture percentage measured by the raw solution measuring unit 31, and an adjustment control unit 42 that controls the conditioning and transfer line 22 and the water injection line 24 based on the moisture percentage measured by the adjusting and measuring unit 32. These components are conceptualized by the function of the control device 40, and do not necessarily have to be clearly distinguished in terms of physical configuration and program configuration.

[0029] The distribution control unit 41 determines whether to transfer the liquid from the stock solution tank 11 to the storage tank 12 or the adjustment tank 13 via the distribution transfer line 21, depending on the magnitude relationship between the moisture content measured by the stock solution measuring unit 31 and a predetermined distribution reference value. In this embodiment, if the moisture content measured by the stock solution measuring unit 31 is equal to or greater than the distribution reference value, the distribution control unit 41 transfers the liquid from the stock solution tank 11 to the storage tank 12 via the distribution transfer line 21. If the moisture content measured by the stock solution measuring unit 31 is less than the distribution reference value, the distribution control unit 41 transfers the liquid from the stock solution tank 11 to the adjustment tank 13 via the distribution transfer line 21. The distribution reference value is preferably a value within a reference range. By setting the distribution reference value within the reference range, the amount of liquid transferred from the storage tank 12 to the adjustment tank 13 can be reduced, enabling stable control and reducing the capacity of the storage tank 12.

[0030] The adjustment control unit 42 adjusts the amount of liquid transferred from the storage tank 12 to the adjustment tank 13 via the adjustment transfer line 22 so that the moisture content measured by the adjustment measurement unit 32 falls within a standard range. Specific adjustment methods that can be used include well-known methods such as PID control and on / off control. In this embodiment, the moisture content of the liquid discharged from the adjustment tank 13 is maintained within the standard range by mixing the liquid with a high moisture content transferred from the stock solution tank 11 to the storage tank 12 with the liquid with a low moisture content transferred from the stock solution tank 11 to the adjustment tank 13. This allows the moisture content of the fiber dissolving solution in the fiber dissolving solution adjustment system 1 to be adjusted to a range that allows reuse as a spinning solution, without having to adjust the moisture content of the resin fibers recovered from the spinning equipment.

[0031] Furthermore, the adjustment control unit 42 can be configured to stop the transfer of liquid from the storage tank 12 to the adjustment tank 13 through the adjustment transfer line 22 when the amount of stored liquid measured by the liquid amount measuring unit 33 is equal to or less than a predetermined lower limit liquid amount, and to inject water into the adjustment tank 13 through the water injection line 24. In this way, by configuring the final water deficiency to be supplemented by injecting water from the water injection line 24, it is possible to use the entire amount of liquid discharged from the stock liquid tank 11 without waste, and to obtain a fiber dissolving liquid that can be used as a spinning solution.

[0032] As is clear from the description of the fiber dissolving liquid preparation system 1, Fig. 2 shows an example of the procedure for the method for adjusting the moisture content of fiber dissolving liquid in the fiber dissolving liquid preparation system 1. This moisture content adjustment method includes a step (step S1) of checking whether the moisture content of the liquid in the raw liquid tank 11 is equal to or greater than the standard value for sorting, a step (step S2) which is executed if the moisture content of the liquid in the raw liquid tank 11 is equal to or greater than the standard value for sorting and transfers the liquid from the raw liquid tank 11 to the storage tank 12, a step (step S3) which is executed if the moisture content of the liquid in the raw liquid tank 11 is not equal to or greater than the standard value for sorting and transfers the liquid from the raw liquid tank 11 to the adjustment tank 13, a step (step S4) which is executed if the moisture content of the liquid in the adjustment tank 13 is equal to or greater than the lower limit of the standard range and transfers the liquid from the raw liquid tank 11 to the storage tank 12. is equal to or greater than the lower limit of the standard range, and is a step of discharging the liquid from the adjustment tank 13 (step S5); a step of checking whether the amount of liquid stored in the storage tank 12 is equal to or less than the lower limit liquid volume (step S6); a step of transferring the liquid from the storage tank 12 to the adjustment tank 13 (step S7); and a step of pouring water into the adjustment tank 13 (step S8), and is executed when the amount of liquid stored in the storage tank 12 is equal to or less than the lower limit liquid volume.

[0033] As described above, in the fiber dissolving liquid adjustment system 1, the distribution control unit 41 temporarily separates the liquid with a high moisture content from the liquid discharged from the stock liquid tank 11 into the storage tank 12, and the adjustment control unit 42 maintains the moisture content of the liquid in the adjustment tank 13 within a standard range by adding the separated liquid to the storage tank 12 so that the moisture content of the liquid in the adjustment tank 13 does not decrease too much. This allows the resin fiber recovered from the spinning equipment to be easily reused as a spinning solution.

[0034] While the present invention has been described above as an embodiment, it is not limited to the above embodiment and various modifications and variations are possible. For example, the fiber dissolving liquid preparation system according to the present invention may be configured to separate liquid having a moisture content below a standard separation value into a storage tank. Furthermore, the fiber dissolving liquid preparation system according to the present invention may be configured to issue an alarm, stop the operation due to an error, or take other appropriate action when the amount of liquid stored in the storage tank falls below a minimum liquid level.

[0035] The fiber dissolving liquid adjustment system of the present invention may further include a retained liquid measuring unit that measures the moisture content of the liquid stored in the storage tank, and the adjustment control unit may be configured to adjust the amount of liquid transferred from the storage tank to the adjustment tank via the adjustment transfer line, taking into account the moisture content measured by the retained liquid measuring unit. [Explanation of symbols]

[0036] 1. Fiber dissolving solution preparation system 11 Stock solution tank 12 Holding tank 121 Mixing device 13 Adjustment tank 131 Mixing device 21 Sorting and Transfer Line 211 Transfer pump 212 Switching valve 22 Regulating Transfer Line 221 Regulating transfer pump 222 Control valve 23 Discharge Line 231 Discharge Pump 24 Water injection line 241 Regulating valve 31 Stock solution measuring section 32 Adjustment measurement section 33 Liquid volume measurement unit 40 Control device 41 Distribution control unit 42 Adjustment control section

Claims

1. a liquid tank for storing a liquid in which resin fibers are dissolved in an organic solvent; a holding tank into which liquid can be transferred from the raw liquid tank; an adjusting tank to which liquid can be transferred from the stock solution tank and the storage tank; a sorting and transferring line that selectively transfers the liquid from the raw liquid tank to either the storage tank or the adjustment tank; a raw liquid measuring unit for measuring the moisture content of the liquid stored in the raw liquid tank; a regulation transfer line that transfers liquid from the storage tank to the regulation tank; a discharge line for discharging liquid from the adjustment tank; an adjusting / measuring unit that measures the moisture content of the liquid stored in the adjusting tank; a distribution control unit that determines whether the liquid is to be transferred from the concentrate tank to the storage tank or the adjustment tank via the distribution transfer line, depending on the magnitude relationship between the moisture content measured by the concentrate measurement unit and a predetermined distribution reference value; an adjustment control unit that adjusts the amount of liquid transferred from the storage tank to the adjustment tank through the adjustment transfer line so that the moisture content measured by the adjustment measurement unit falls within a predetermined reference range; A fiber dissolving solution adjusting system comprising:

2. The fiber dissolving solution adjusting system according to claim 1 , wherein the distribution reference value is a value within the reference range.

3. 3. The fiber dissolving liquid preparation system according to claim 1, wherein the distribution control unit causes the distribution transfer line to transfer the liquid from the raw liquid tank to the storage tank when the moisture content measured by the raw liquid measurement unit is equal to or greater than the distribution reference value, and causes the distribution transfer line to transfer the liquid from the raw liquid tank to the preparation tank when the moisture content measured by the raw liquid measurement unit is less than the distribution reference value.

4. a water injection line for injecting water into the adjusting tank; a liquid volume measuring unit for measuring the liquid volume stored in the storage tank; Furthermore, The fiber dissolving liquid adjustment system of claim 3, wherein the adjustment control unit stops the transfer of liquid to the adjustment transfer line and injects water into the adjustment tank through the water injection line when the liquid storage amount measured by the liquid volume measuring unit is below a predetermined lower limit liquid volume.

5. 3. The fiber dissolving liquid preparation system according to claim 1, wherein the lower limit of the reference range is equal to or greater than the average moisture content of the liquid supplied to the liquid source tank.

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