Method for extracting cellulose online from multi-component fabrics and cellulose separation system

Abstract

The present invention relates to the field of textile technology, and in particular to a method for online extraction of cellulose from a multi-component fabric and a cellulose separation system, wherein the multi-component fabric comprises at least one non-cellulose fiber and at least one cellulose fiber; the method comprises the steps of reacting the multi-component fabric in an acid solution with a mass concentration of 1% to 15% and simultaneously performing online extraction of cellulose based on circulating filtration to obtain cellulose powder. The method for online extraction of cellulose from a multi-component fabric provided by the present invention can realize online extraction of cellulose with a high recovery rate from a fabric blended with multiple cellulose fibers and non-cellulose fibers.

Description

Technical Field

[0001] The invention relates to the field of textile technology, in particular to a method for online extraction of cellulose from multi-component fabrics and a cellulose separation system. Background Art

[0002] Among textiles, single fiber fabrics account for a very low proportion, and most of them are multi-component blended or interwoven fabrics. Among them, multi-component fabrics containing cellulose fibers are the main ones, such as polyester / cotton, cotton / spandex, cotton / nylon, viscose / polyester, viscose / nylon / spandex, etc., accounting for more than 85% of clothing fabrics. These multi-component fabrics, due to the entanglement of different types of fibers, traditional mechanized opening methods cannot separate fibers of different components. In addition, the source and component ratio of these multi-component waste textiles are often unknown, which leads to the quality of mechanically recycled products cannot be controlled; in addition, non-cellulose fibers in multi-component waste textiles, such as spandex components, are easy to entangle equipment, causing blockage, which makes it difficult to mechanically recycle the waste fabrics by opening and spinning. Therefore, under the current technical background, multi-component fabrics can only be used as low-end fillers, with poor recycling economic benefits and small scale. This also directly leads to the difficulty in expanding the scale of domestic waste textile recycling and increasing the industry output value, which is one of the current industry pain points.

[0003] Through chemical methods, the physical form of cotton or other cellulose fibers in multi-component fabrics can be changed so that they are no longer entangled with other component fibers, making them easier to separate. For example, cotton fibers will undergo acid hydrolysis under the action of acid. The acid hydrolysis mainly occurs in the non-crystalline area, and the cotton fibers will eventually be transformed into micron-sized cellulose powder with low degree of polymerization (DP; DP = 100-300). In this process, non-cellulose fibers, such as polyester fibers, are basically unaffected and can still maintain the initial fiber / fabric structure (A new methodology to recycle polyester from fabric blends with cellulose, Cellulose, 2010, 17, 215-222).

[0004] Chinese invention patent CN108424466A discloses a method for separating polyester-cotton blended fabrics by acid hydrolysis: at 95°C, under the conditions of hydrochloric acid aqueous solution, the cotton fibers in the polyester-cotton blended fabric are hydrolyzed into micron-sized cellulose powder (particles). During this process, the polyester is not affected and still maintains the initial fabric structure. After the acid hydrolysis reaction is completed, the polyester component and the cotton component can be separated and recovered by conventional separation methods based on the size difference between the cotton cellulose powder and the polyester fiber. The recovered cotton cellulose powder can be used as microcrystalline cellulose, but the cellulose powder recovery rate is less than 40%, and the cellulose component is seriously lost / lost.

[0005] Similarly, Chinese invention patent CN109467741A discloses a method for hydrolyzing cotton fibers into cellulose powder using an aqueous solution of an organic acid in a hydrothermal environment (110-150°C), and then separating the polyester fibers from the cellulose powder based on the difference in their physical sizes. The cellulose recovery rate is about 80%, but the price of organic acids (citric acid, p-toluenesulfonic acid, etc.) is much higher than that of traditional inorganic acids (sulfuric acid, hydrochloric acid, etc.), which increases the cost.

[0006] In addition to the specific implementation process, in fact, the degree of polymerization and crystallinity of cellulose fibers will also affect the recovery rate of cellulose. Under the same acid hydrolysis conditions, the lower the degree of polymerization or crystallinity of the cellulose fiber, the lower its cellulose yield. Due to the different raw materials used by different cellulose fibers (cotton or dissolving pulp with different degrees of polymerization or crystallinity), the different post-processing procedures that cotton fibers undergo in the process of weaving into fabrics (some post-processing procedures will change the degree of polymerization and crystallinity of cellulose fibers), and the different aging histories of cellulose fiber fabrics during use, the acid hydrolysis recovery rates of different cellulose fibers vary greatly, but generally speaking, the cellulose yield of cotton fibers is higher than that of regenerated cellulose fibers such as viscose and lyocell; the cellulose recovery rate of pre-consumption cellulose fibers is higher than that of post-consumption cellulose fibers. Among them, the pre-consumption refers to waste scraps and the like that appear in the industrial production process; the post-consumption refers to waste generated after use by consumers.

[0007] The above patent involves an implementation method for acid hydrolysis and separation of polyester / cotton blended fabrics. The acid hydrolysis reaction is carried out in a glass flask or a small high-pressure reactor. After obtaining the unseparated, mixed polyester and cotton powder (cellulose powder) slurry through the acid hydrolysis reaction, it is necessary to go through an additional separation process to complete the separation of the polyester and cotton cellulose components to achieve the purpose of extracting cellulose, that is, the acid hydrolysis process and the separation process are not carried out simultaneously. Secondly, in the above implementation method, the recovery rate of the cellulose component is still low, the loss is large, and it is difficult to meet the needs of commercial operation. In addition, the non-cellulose fiber involved in the above patent is only polyester. It is not known whether it is still applicable when the non-cellulose fiber is nylon, spandex, and other synthetic fibers that have a completely different molecular structure from polyester. Summary of the invention

[0008] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a method for online extraction of cellulose from multi-component fabrics and a cellulose separation system which can simultaneously perform acid hydrolysis and separation processes.

[0009] In order to solve the above technical problems, the present invention provides a method for online extraction of cellulose in a multi-component fabric, wherein the multi-component fabric comprises at least one non-cellulose fiber and at least one cellulose fiber;

[0010] The method comprises the steps of reacting the multi-component fabric in an acid solution with a mass concentration of 1% to 15% and simultaneously performing online cellulose extraction based on circulating filtration to obtain cellulose powder.

[0011] Further providing a cellulose separation system, comprising a reactor, a cellulose powder collector, a circulation pump, and a non-cellulose fiber collector;

[0012] Wherein, the reactor comprises a discharge port and a discharge port, and a stirring paddle and a heating module arranged inside the reactor;

[0013] The discharge port, the cellulose powder collector and the non-cellulose fiber collector are all provided with filter screens;

[0014] The cellulose powder collector is connected to the discharge port through a pipeline, and the non-cellulose fiber collector is connected to the discharge port through a pipeline; the liquid inlet end of the circulation pump is connected to the liquid outlet end of the cellulose powder collector and the liquid outlet end of the non-cellulose fiber collector through pipelines, respectively, and the liquid outlet end of the circulation pump is connected to the reactor through a pipeline;

[0015] The reactor is used to contain the multi-component fabric and the acidic solution;

[0016] The multi-component fabric includes at least one non-cellulosic fiber and at least one cellulosic fiber;

[0017] The mass concentration of the acidic solution is 1% to 15%.

[0018] The beneficial effects of the present invention are as follows: the separation method provided by the present invention can realize the online extraction of cellulose fibers, that is, the acid hydrolysis and separation processes are carried out simultaneously, which overcomes the disadvantage of the existing process that the cellulose fibers need to be finally extracted and separated after the acid hydrolysis is completed, thereby saving time and cost. In addition, compared with the traditional non-online extraction method (acid hydrolysis and separation processes are carried out sequentially), the method provided by the present invention can improve the recovery rate of cellulose and reduce the loss of cellulose components. Finally, the present invention can separate cellulose fibers from a variety of synthetic fibers by controlling the mass concentration of the acidic solution, thereby improving the applicability of the separation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic structural diagram of a cellulose separation system in a specific embodiment of the present invention.

[0020] Explanation of reference numerals: 1. Reactor; 2. Cellulose powder collector; 3. Discharge port; 4. Circulation pump; 5. Discharge port; 6. Non-cellulose fiber collector. DETAILED DESCRIPTION

[0021] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0022] A method for online extraction of cellulose in a multi-component fabric, wherein the multi-component fabric includes at least one non-cellulose fiber and at least one cellulose fiber; the method includes the steps of reacting the multi-component fabric in an acidic solution with a mass concentration of 1% to 15% and simultaneously performing online cellulose extraction based on circulating filtration to obtain cellulose powder.

[0023] The cellulose fiber is selected from at least one of natural cellulose fiber, natural regenerated cellulose fiber and regenerated cellulose modified fiber, such as cotton fiber, hemp fiber, acetate fiber, viscose fiber, lyocell fiber, cuprammonium fiber and other regenerated cellulose fibers or modified fibers thereof.

[0024] The non-cellulose fiber is a synthetic fiber, such as at least one of polyester, nylon, spandex, polypropylene, acrylic and the like.

[0025] In one embodiment, the acidic solution is an aqueous solution of hydrochloric acid and / or sulfuric acid. The mass concentration of the acidic solution is 1% to 15%, preferably 2% to 10%. At this mass concentration, the subsequent waste acid treatment pressure is low, and the cotton fiber can be decomposed into micron-sized powder instead of cellulose fiber. The mass loss (degradation) is not large or negligible, and the initial fiber morphology can still be maintained, that is, the acidic solution at this mass concentration can selectively degrade cotton fiber (cellulose fiber).

[0026] Specifically, the method comprises the following steps:

[0027] S1, breaking the multi-component fabric to obtain rags;

[0028] S2, mixing the rags in the acidic solution and heating to a reaction temperature, and circulating a reaction solution consisting of the acidic solution and the cellulose particles acidified and decomposed from the rags through a filter screen until no more cellulose particles are dissolved from the rags;

[0029] S3, collecting the rag residues and the cellulose particles retained by the filter, washing and drying them to obtain non-cellulose fibers and cellulose powder respectively.

[0030] During the acid hydrolysis reaction, the ratio between the rags and the acid solution is crucial. When the concentration of the rags is too high, the reaction is incomplete and a large amount of cellulose fibers are not hydrolyzed. When the concentration of the rags is too low, the production efficiency is low and the energy consumption is high. Therefore, the mass ratio of the rags to the acid solution is preferably 1: (5-100), and more preferably 1: (10-50).

[0031] The reaction temperature is 80-160°C, preferably 90-150°C. When the reaction temperature is higher than the boiling point of the acidic solution under normal pressure, it must be carried out in a closed reactor. The higher the temperature, the smaller the minimum acid dosage for degrading the cellulose fibers into powder. However, when the temperature is higher than 150°C, non-cellulose fibers will also undergo non-negligible degradation, resulting in mass loss and reduced recovery rate. Lowering the temperature can save heating energy, but the required acid concentration is also higher, and the cost of waste acid treatment increases.

[0032] The size of the rags can be considered according to the convenience of actual production and operation. The size of the rags is preferably 8 to 200 cm. 2 By breaking up the cloth, the contact area between the cloth and the acid solution is increased, thereby increasing the reactivity (reaction rate, reaction degree, etc.), and facilitating the feeding and discharging of the reactor.

[0033] The reaction time directly determines the extent of the acidolysis reaction. When the reaction time is too short, the extent of acidolysis is insufficient, and cellulose fibers such as cotton fibers are difficult to convert into suitable particles. When the reaction time is too long, there is a problem of excessive degradation of cellulose fibers, which seriously reduces the recovery rate of cellulose fibers. Therefore, in the acidolysis reaction process in which acidification and separation are carried out simultaneously, the reaction time is preferably 15 to 240 minutes, and more preferably 20 to 180 minutes.

[0034] In one embodiment, see Figure 1As shown, the reaction process is carried out in a cellulose separation system. The cellulose separation system includes a reactor 1, a cellulose powder collector 2, a circulation pump 4 and a non-cellulose fiber collector 6. Wherein, the reactor includes a discharge port 3 and a discharge port 5, as well as a stirring paddle and a heating module arranged therein. The discharge port, the cellulose powder collector and the non-cellulose fiber collector are all provided with filter screens. The discharge port and the discharge port are both provided with control valves. The cellulose powder collector is connected to the discharge port through a pipeline, and the non-cellulose fiber collector is connected to the discharge port through a pipeline. The liquid inlet end of the circulation pump is respectively connected to the liquid outlet end of the cellulose powder collector and the liquid outlet end of the non-cellulose fiber collector through a pipeline, and the liquid outlet end of the circulation pump is connected to the reactor through a pipeline. Specifically speaking, first, pour the rags and the acid solution into the reactor (the control valves of the discharge port and the discharge port are both closed) and mix them, and stir them with the stirring paddle and heat them with the heating module. When heated to the preset reaction temperature, open the control valve of the discharge port (the control valve of the discharge port is closed at this time), so that the acid solution with dispersed cellulose particles enters the cellulose powder collector through the discharge port, and finally re-enters the reactor through the circulation pump. In this process, the filter screen on the discharge port is used to intercept non-cellulose fiber components to ensure that the non-cellulose fibers stay inside the reactor, and the cellulose particles produced by acid hydrolysis will pass through the filter screen at the discharge port with the liquid due to their small particle size (1-200 μm), and when passing through the cellulose powder collector, they will be intercepted by the filter screen in the cellulose powder collector. This cycle is repeated until no more cellulose particles are dissolved from the rags, or when the preset reaction time is reached, the discharge port is closed and the discharge port is opened. At this time, the rag residue in the reactor (the remaining non-cellulose fiber components after the cellulose components are separated) is sent to the non-cellulose fiber collector through the discharge port, and the acid solution is re-sent into the reactor through the circulation pump (the control valve of the discharge port is in a closed state at this time), so the acidic substance can be re-added for use in the next cycle. The non-cellulose fibers in the non-cellulose fiber collector and the cellulose particles in the cellulose powder collector are washed with alkaline or neutral water, and then dried to obtain non-cellulose fibers and cellulose powder, respectively.

[0035] Of course, in the above process, the rags and the acidic solution can also be mixed by gas bubbling or other methods instead of the stirring paddle. The filter screen on the discharge port can be integrally formed with the reactor, or connected to the connecting flange or integrally formed with the connecting flange, and fixed to the discharge port through the connecting flange. Among them, the pore size of the filter screen located on the discharge port should be larger than the particle size of the cellulose particles (1 to 200 μm) but smaller than the minimum side length of the rags, so as to allow the cellulose particles to pass through the filter screen and flow into the cellulose powder collector, while retaining the non-cellulose fibers in the reactor. The pore size of the filter screen located in the cellulose powder collector should be smaller than the particle size of the cellulose particles, so as to retain the cellulose particles in the acidic solution in the cellulose powder collector. Similarly, a filter screen is also provided in the non-cellulose fiber collector, and its pore size should be smaller than the minimum side length of the rags, so that the rags (non-cellulose fibers) after the cellulose powder is extracted can be retained and collected by the non-cellulose fiber collector.

[0036] The pore size of the filter should be selected according to the particle size of the cellulose particles (unwashed and dried cellulose powder) and the minimum side length of the rags. For example, when the minimum side length of the rags is 5 cm, the pore size a of the filter at the discharge port is preferably 1 μm < a < 5 cm, more preferably 500 μm < a < 2 cm; and for the filter in the cellulose powder collector, the pore size b is preferably b < 5 μm, more preferably b < 1 μm.

[0037] It should be noted that the filter screen described herein may be of any shape, such as a flat filter screen or a basket-shaped filter basket. The aperture refers to the diameter of the largest filter hole in the filter screen. In this embodiment, the aperture of the filter holes in the filter screen may be non-uniform or uniform.

[0038] In one embodiment, the acidic wastewater generated when washing cellulose particles and non-cellulose fibers can be fed back into the reactor after adding acid and used as the acidic solution required for acid hydrolysis. It can also be directly discharged into a wastewater treatment device for purification after neutralization to meet the discharge standards.

[0039] The cellulose online extraction method provided by the present invention also has the beneficial effects of improving the cellulose recovery rate (extraction rate) and reducing the loss of cellulose components. In the traditional cellulose separation and extraction process (the acid hydrolysis process and the extraction and separation process are carried out in sequence), the cellulose powder generated by the acid hydrolysis of the cellulose fibers cannot be separated from the acid hydrolysis system in time. Only when all the cellulose fibers are converted into powder form can the acid hydrolysis reaction be terminated, and the powdered cellulose can be separated from the remaining fibers / fabrics through the subsequent separation and extraction process. In this process, due to the unevenness of the reaction and the fact that the acid hydrolysis rate of the cellulose fibers on the surface of the fabric is higher than that of the cellulose fibers inside the fabric, the cellulose powder generated early undergoes additional acid hydrolysis time, resulting in an aggravated degree of degradation and increased mass loss.

[0040] The online extraction method provided by the present invention has been verified by the inventors to effectively improve the cellulose yield. The inventors believe that the reasons for obtaining the above-mentioned beneficial effects include but are not limited to: during the online extraction process, once the cellulose powder in the reactor is generated, it will be extracted online from the reactor to the filter screen in the cellulose powder collector. Due to the action of the circulation pump, the cellulose powder forms a filter layer on the filter screen and is in a tightly stacked state. In this state, the hydrogen bonding effect between the cellulose powders is greatly enhanced, the hydrolysis activity of the ether oxygen bonds on the main chain of the cellulose molecules on the surface of the powder is reduced, and the acidic hydrolysis is inhibited, that is, the rate of continued degradation of the cellulose powder collected in the cellulose powder collector is greatly reduced, and the mass loss is also reduced, thereby improving the recovery rate.

[0041] It should be noted that the recovery rate below is calculated based on mass loss.

[0042] Example 1

[0043] See also Figure 1As shown, the method for online extraction of cellulose in multi-component fabrics comprises the following steps: 200 g of polyester-cotton blended fabric (polyester content 65%) is crushed into 2×4 cm size; the above-mentioned scraps are mixed with 10 L A 2 wt % aqueous hydrochloric acid solution was added to a 13 L reactor 1, and the stirring paddle of the reactor was turned on to mix the reactants evenly; the heating module of the reactor 1 was turned on to heat the mixture in the reactor to 150° C.; the side discharge port 3 of the reactor 1 (the discharge port was provided with a filter screen with a pore size of 1 mm) was opened to discharge the cellulose particles and acidic liquid formed by the acid hydrolysis of the cellulose fibers in the reactor from the discharge port 3 to a cellulose powder collector 2 (3 L in volume, equipped with a 1.5 L filter basket with a pore size of 1 μm), and the liquid passing through the cellulose powder collector 2 was pumped back to the reactor 1 through a circulation pump (flow rate controlled at 100 L / h), and the cycle was repeated until the liquid in the reactor 1 did not contain cellulose powder, then the reaction was stopped and the discharge port 3 was closed; the discharge port 5 of the reactor 1 was opened to discharge the solid-liquid mixture (rag residue and acidic solution) in the reactor 1 into a non-cellulose fiber collector 6 (6 L in volume, equipped with a 3L filter basket with a filter hole size of 1.5mm), close the discharge port 5; pump the acidic solution in the non-cellulose fiber collector 6 back to the reactor 1 through the circulation pump 4; pass neutral or alkaline water into the non-cellulose fiber collector 6 and the cellulose powder collector 2 to clean the non-cellulose fibers and cellulose powder in the collector, and the waste liquid generated by the cleaning is extracted by the circulation pump and collected separately. When the extracted liquid is neutral, stop cleaning, take out the non-cellulose fibers and cellulose powder in the non-cellulose collector 6 and the cellulose powder collector 2, dry them at a drying temperature of 80°C and a drying time of 24h, and then perform analysis and testing (the purity detection method is carried out according to GB / T2910-2009 standard); add 2wt% hydrochloric acid aqueous solution to the reactor 1 to make the internal acid solution volume reach 10L, add 200g of polyester-cotton blended fabric (polyester content 65%) crushed into 2×4cm size again, and start the next round of extraction and separation reaction.

[0044] The analysis and test results are shown in Table 1.

[0045] Table 1

[0046]

[0047] Example 2

[0048] The method for online extraction of cellulose in multi-component fabrics is different from that in Example 1 in that the polyester-cotton blended fabric is replaced by a cotton / nylon blended fabric (cotton content 65%).

[0049] The analysis and test results are shown in Table 2.

[0050] Table 2

[0051]

[0052] Example 3

[0053] The method for online extraction of cellulose in multi-component fabrics is different from that of Example 1 in that the polyester-cotton blended fabric is replaced with a cotton / spandex blended fabric (cotton content 90%), the concentration of the acid solution is 10 wt%, and the reaction temperature is set to 90°C.

[0054] The analysis and test results are shown in Table 3.

[0055] Table 3

[0056]

[0057] Example 4

[0058] The method for online extraction of cellulose from multi-component fabrics is different from that of Example 1 in that the polyester-cotton blended fabric is replaced by a viscose / polyester blended fabric (viscose content 35%).

[0059] The analysis and test results are shown in Table 4.

[0060] Table 4

[0061]

[0062] Example 5

[0063] The method for online extraction of cellulose in multi-component fabrics is different from that of Example 1 in that the polyester-cotton blended fabric is replaced with a polyester / cotton / nylon / spandex blended fabric (cotton content 30%).

[0064] The analysis and test results are shown in Table 5.

[0065] Table 5

[0066]

[0067] Description of the beneficial effects of improving cellulose recovery rate:

[0068] Example 6

[0069] The method for online extraction of cellulose in multi-component fabrics is different from that in Example 1 in that the polyester-cotton blended fabric is replaced by single-component cotton fabric A (degree of polymerization DP: 1160; degree of crystallinity: 61.5%), cotton fabric B (degree of polymerization DP: 726; degree of crystallinity: 56.3%) or viscose fabric C (degree of polymerization DP: 491; degree of crystallinity 44.9%), and the reaction time is set to 3 hours.

[0070] Example 7

[0071] The method for online extraction of cellulose in multi-component fabrics is different from that of Example 6 in that: before the reaction, the filter screen in the cellulose powder collector 2 is removed (in this state, the cellulose powder collector cannot collect cellulose powder, that is, the online extraction function cannot be realized); after the reaction is completed, the remaining acid hydrolyzate and the suspension mixture composed of solid cotton cellulose in the system are all discharged into a separately prepared filtration device (Buchner funnel + filtration bottle + vacuum pump; using 1 μm filter paper) for vacuum filtration to obtain a cellulose filter cake, which is filtered and washed with clean water until it is neutral, dried at a drying temperature of 80° C. and a drying time of 24 h, and then weighed.

[0072] The cellulose recovery results and comparisons of Examples 6-7 are shown in Table 6.

[0073] Table 6

[0074]

[0075] As can be seen from Tables 1 to 6, the method for online extraction of cellulose from multi-component fabrics provided by the present invention can be applied to a variety of blended materials of non-cellulose fibers and cellulose fibers, and the recovery rate and recovery purity of cellulose powder, as well as the recovery rate and recovery purity of non-cellulose fibers are high. At the same time, the first round and the subsequent rounds of cycles show similar recovery rates and purities of non-cellulose fibers and cellulose powder, that is, the method for online extraction of cellulose from multi-component fabrics provided by the present invention can effectively shorten the processing time and reduce the processing cost.

[0076] In summary, the method for online extraction of cellulose from multi-component fabrics provided by the present invention can realize online extraction of cellulose fibers, that is, realize simultaneous acid hydrolysis and separation processes, overcome the disadvantage of the existing process that an additional separation process is required after the acid hydrolysis is completed to finally extract and separate cellulose fibers, thereby saving time and cost. In addition, compared with the traditional non-online extraction method (acid hydrolysis and separation processes are carried out sequentially), the method provided by the present invention can improve the recovery rate of cellulose and reduce the loss of cellulose components. Finally, the present invention can separate cellulose fibers from a variety of synthetic fibers by controlling the mass concentration of the acidic solution, thereby improving the applicability of the separation method.

[0077] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for online extraction of cellulose from a multi-component fabric, characterized in that: The multi-component fabric includes at least one non-cellulosic fiber and at least one cellulosic fiber; The method is carried out in a cellulose separation system, which comprises a reactor, a cellulose powder collector, a circulation pump and a non-cellulose fiber collector; wherein the reactor comprises a discharge port and a discharge port, and a stirring paddle and a heating module arranged inside the reactor; the discharge port, the cellulose powder collector and the non-cellulose fiber collector are all provided with filter screens; the cellulose powder collector is connected to the discharge port through a pipeline, and the non-cellulose fiber collector is connected to the discharge port through a pipeline; the liquid inlet end of the circulation pump is respectively connected to the liquid outlet end of the cellulose powder collector and the liquid outlet end of the non-cellulose fiber collector through a pipeline, and the liquid outlet end of the circulation pump is connected to the reactor through a pipeline; The method comprises the following steps: S1, breaking the multi-component fabric to obtain rags; S2, adding the rags and an acidic solution with a mass concentration of 1% to 15% into a reactor for mixing, and heating to 80 to 160° C., and circulating a reaction solution consisting of the acidic solution and the cellulose particles acidified and decomposed from the rags through a filter screen until no more cellulose particles are dissolved from the rags; the acidic solution is an aqueous solution of hydrochloric acid and / or sulfuric acid, and the mass ratio of the rags to the acidic solution is 1:(5 to 100); S3, collecting the rag residues and the cellulose particles retained by the filter, washing and drying them to obtain non-cellulose fibers and cellulose powder respectively.

2. The method according to claim 1, characterized in that: The cellulose fiber is selected from at least one of natural cellulose fiber, natural regenerated cellulose fiber and regenerated cellulose modified fiber.

3. The method according to claim 1, characterized in that: The non-cellulosic fibers are synthetic fibers.

4. The method according to claim 1, characterized in that: The mass concentration of the acidic solution is 2% to 10%.

5. The method according to claim 1, characterized in that: The size of the rags is 10~200cm 2 .

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