A modified fiber for removing chlorine-containing compounds, and a method for preparing and using the same

Abstract

The application discloses a preparation method of modified fiber for removing chlorine-containing compounds, and belongs to the technical field of chlorine-containing compound removal. The preparation method comprises the following steps: reacting polyacrylonitrile fiber with an amine compound to obtain aminated polyacrylonitrile fiber; and reacting the aminated polyacrylonitrile fiber with a pyridine compound to obtain the modified fiber for removing chlorine-containing compounds. The modified fiber prepared by the preparation method contains specific contents of amino functional groups and pyridine functional groups, and has the characteristics of good adsorption performance, effective removal of organic chlorine and inorganic chlorine, no pollution, simple process and convenient operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of removing chlorinated compounds, and particularly relates to a modified fiber for removing chlorinated compounds and a preparation method and application thereof. BACKGROUND

[0002] The main components of gasoline, naphtha, aviation fuel oil and diesel are aliphatic hydrocarbons and naphthenes, and contain trace amounts of inorganic chlorine and organic chlorine. Since chlorine has a very high electron affinity, it is easy to react with many substances and migrate with process fluids, which is very harmful to equipment, catalysts and devices, and also has a certain impact on product performance. Therefore, the concentration of chlorinated compounds in the raw material must be strictly controlled to meet the process and product performance requirements.

[0003] The widely used dechlorination technology in the industry at present is hydrogenation dechlorination, but in the process of hydrogenation dechlorination, a specific catalyst is needed, the generated HCl has high corrosion to the equipment material, and an alkali washing method needs to be added to remove it, the process is complex, the energy consumption is high, and the dechlorination agent used in catalytic hydrogenation has the problems of low chlorine removal rate and difficult catalyst regeneration. The existing other dechlorination technologies also have the problems of high energy consumption, low chlorine removal rate, difficult regeneration and non-green, low-carbon and environmentally friendly process. Patent CN103611566A discloses a catalyst for removing organic chlorine in high-chlorine oil and a preparation method thereof. The catalyst prepared by the method has high hydrogenation dechlorination activity and stability, but is only suitable for treating high-chlorine-content naphtha and other light oil products. US5928500A discloses an adsorbent for removing chlorides in hydrocarbon raw materials and a regeneration method thereof. The adsorbent has the disadvantages of frequent regeneration and rapid decline in chloride removal effect after more than 16 hours of contact with the raw material. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a modified fiber for removing chlorinated compounds, which has the characteristics of good adsorption performance, effective removal of organic chlorine and inorganic chlorine, no pollution, simple process and easy operation. The present application also provides a preparation method thereof, which has a simple preparation process, is easy to operate and has good repeatability, and is suitable for large-scale industrial application.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a preparation method of a modified fiber for removing chlorinated compounds is provided, which comprises the following steps:

[0006] (1) mixing polyacrylonitrile fiber (abbreviated as PAN fiber), amine compound and solvent, and reacting under ultrasonic wave condition, washing the reacted fiber to neutral, and drying to obtain amine-modified polyacrylonitrile fiber;

[0007] (2) mixing the amine-modified polyacrylonitrile fiber of step (1), a pyridine compound and a solvent, and reacting, and washing the reacted fiber to neutral, and drying to obtain the modified fiber for removing chlorine-containing compounds.

[0008] In some embodiments, in step (1), the amine compound includes one or more of polyethyleneimine, diethylene triamine, and triethylene tetramine.

[0009] In some embodiments, in step (1), the mass ratio of the polyacrylonitrile fiber to the amine compound is 1: (1-5).

[0010] In some embodiments, in step (1), the reaction temperature is 60-150°C.

[0011] In some embodiments, in step (1), the reaction pressure is 0-0.5 MPa.

[0012] In some embodiments, in step (1), the reaction time is 2-24 h.

[0013] In some embodiments, in step (1), the drying temperature is 60-90°C, and the drying time is 12-24 h.

[0014] In some embodiments, in step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridine formaldehyde, 3-pyridine formaldehyde, and 4-pyridine formaldehyde.

[0015] In some embodiments, in steps (1) and (2), the solvent is independently selected from one or more of water, ethanol, butanone, ethylene glycol, and 1,4-dioxane.

[0016] In some embodiments, in step (2), the mass ratio of the amine-modified polyacrylonitrile fiber to the pyridine compound is 1: (1-4).

[0017] In some embodiments, in step (2), the reaction temperature is 40-80°C.

[0018] In some embodiments, in step (2), the reaction pressure is 0-0.2 MPa.

[0019] In some embodiments, in step (2), the reaction time is 2-10 h.

[0020] In some embodiments, in step (2), the drying temperature is 60-90°C, and the drying time is 12-24 h.

[0021] According to another aspect of the present application, there is further provided a modified fiber for removing chlorine-containing compounds, prepared according to the above preparation method, wherein the modified fiber has pyridine functional groups and amino functional groups.

[0022] In some embodiments, the content of the pyridine functional groups is 0.50wt%-2.1wt%, and the content of the amino functional groups is 2.00wt%-6.50wt%, based on the total weight of the modified fiber.

[0023] According to another aspect of the present application, there is further provided a method for using the modified fiber for removing chlorine-containing compounds from hydrocarbon substances, which specifically comprises the following steps:

[0024] (1) packing the modified fiber in a fixed bed reactor;

[0025] (2) passing a raw material containing chlorine-containing compounds into the fixed bed reactor for removing the chlorine-containing compounds.

[0026] In some embodiments, in step (1), the packing height-diameter ratio of the fixed bed reactor is 2:1-12:1.

[0027] In some embodiments, in step (2), the volume space velocity of the raw material is 0.1h -1 -80h -1 .

[0028] In some embodiments, in step (2), the operating pressure of the fixed bed reactor is 0MPa-0.5MPa.

[0029] In some embodiments, in step (2), the reaction temperature of the fixed bed reactor is 25℃-80℃.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] (1) The modified fiber for removing chlorine-containing compounds can be used for removing trace amounts of chlorine-containing compounds from hydrocarbon substances. The modified fiber contains specific contents of amino functional groups and pyridine functional groups, and has the characteristics of good adsorption performance, effective removal of organic chlorine and inorganic chlorine, no pollution, simple process, and easy operation.

[0032] (2) The preparation method is simple, easy to operate, and has good repeatability, and is suitable for large-scale industrial application.

[0033] (3) The present application uses a process combining synthetic modified materials with an adsorption fixed bed, and through the design of synthetic modified grafted PAN fibers and the optimization of the adsorption conditions of the fixed bed, the effective removal of trace amounts of chlorine from hydrocarbon substances is achieved. DETAILED DESCRIPTION

[0034] To enable those skilled in the art to have a better understanding of the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0035] Herein, trace refers to the content of the chlorine-containing compound in the hydrocarbon substance being 1-50 ppm.

[0036] Theories or mechanisms described and disclosed herein, whether right or wrong, should not limit the scope of the present application in any way, i.e., the present application can be implemented without being limited by any particular theory or mechanism.

[0037] Herein, when describing embodiments or examples, it should be understood that they are not intended to limit the present application to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the described methods and materials included in the scope defined by the claims.

[0038] Herein, for the sake of brevity, all possible combinations of the various technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not conflict, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope of the present specification.

[0039] The present application provides a modified fiber for removing chlorine-containing compounds, which has the characteristics of good adsorption performance, effective removal of organic chlorine and inorganic chlorine, no pollution, simple process and easy operation; the present application also provides a preparation method thereof, which is simple, easy to operate and has good repeatability, and is suitable for large-scale industrial application.

[0040] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a preparation method of a modified fiber for removing chlorine-containing compounds is provided, comprising the following steps:

[0041] (1) mixing polyacrylonitrile fiber, amine compound and solvent, and reacting under ultrasonic wave condition, washing the reacted fiber to neutral, and drying to obtain amine-modified polyacrylonitrile fiber;

[0042] (2) mixing the amine-modified polyacrylonitrile fiber of step (1), pyridine compound and solvent, and reacting, washing the reacted fiber to neutral, and drying to obtain the modified fiber for removing chlorine-containing compounds.

[0043] The present invention has no special limitation on the raw material polyacrylonitrile fiber, and conventional polyacrylonitrile fiber in the art can be used. For example, the diameter of the polyacrylonitrile fiber can be 1.5dtex-3dtex, and the length of the polyacrylonitrile fiber can be 35mm-50mm. Polyacrylonitrile fibers of different specifications have no obvious effect on the dechlorination performance of the modified product.

[0044] According to the preparation method of the present invention, in step (1), the amine compound includes one or more of polyethyleneimine, diethylenetriamine, and triethylenetetramine. The inventors have discovered that by reacting the amine compound of the present invention with polyacrylonitrile fiber, a grafted modified fiber can be obtained. The grafted modified fiber has a side chain containing an amino functional group, and the amino functional group in the side chain can effectively remove inorganic chlorine from hydrocarbon substances.

[0045] According to the preparation method of the present invention, in step (1), the mass ratio of the polyacrylonitrile fiber to the amine compound is 1:(1-5). It is understood that the mass ratio of the polyacrylonitrile fiber to the amine compound can be any specific value of 1:1, 1:2, 1:3, 1:4, 1:5, or any value within the range of 1:(1-5). The inventors have found that by controlling the mass ratio of the polyacrylonitrile fiber to the amine compound within an appropriate range, the reaction between the polyacrylonitrile fiber and the amine compound can be maximized while optimizing the economic cost.

[0046] According to the preparation method of the present invention, in step (1), the ultrasonic frequency is 30kHz-60kHz. It can be understood that the ultrasonic frequency can be any specific value among 30kHz, 35kHz, 40kHz, 45kHz, 50kHz, 55kHz, 60kHz or any value within the range of 30kHz-60kHz.

[0047] According to the preparation method of the present invention, in step (1), the reaction temperature is 60°C-150°C. It can be understood that the reaction temperature can be any specific value of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or any value within the range of 60°C-150°C.

[0048] Furthermore, according to the preparation method of the present invention, in step (1), the reaction temperature is preferably 70°C-110°C.

[0049] According to the preparation method of the present invention, in step (1), the reaction pressure is 0 MPa-0.5 MPa. It can be understood that the reaction pressure can be any specific value among 0, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa or any value within the range of 0 MPa-0.5 MPa.

[0050] Further, according to the preparation method of the present application, in step (1), the reaction pressure is preferably 0 MPa-0.2 MPa.

[0051] According to the preparation method of the present application, in step (1), the reaction time is 2h-24h, and it can be understood that the reaction time can be any specific value among 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h or any value within the range of 2h-24h.

[0052] In the present application, in step (1), the washing method of the fiber after reaction is not specifically limited, and a conventional washing method in the art can be used, for example, deionized water can be used for washing, or a mixed solution of deionized water and alcohol can be used for washing.

[0053] According to the preparation method of the present application, in step (1), the drying temperature is 60℃-90℃, and it can be understood that the drying temperature can be any specific value among 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃ or any value within the range of 60℃-90℃; the drying time is 12h-24h, and it can be understood that the drying time can be any specific value among 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h or any value within the range of 12h-24h. The present application does not have a specific limitation on the specific drying method, and a conventional drying method in the art can be used, for example, suction filtration followed by drying or direct drying.

[0054] According to the preparation method of the present application, in step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridine formaldehyde, 3-pyridine formaldehyde, and 4-pyridine formaldehyde.

[0055] In the present application, by using a specific kind of pyridine compound and amine compound to modify the polyacrylonitrile fiber, the modified fiber contains a specific content of amino functional group and pyridine functional group; the pyridine functional group can effectively adsorb trace organic chlorides in hydrocarbon substances, and the amino functional group can form ammonium chloride salt with inorganic chlorine, thereby effectively removing the inorganic chlorine.

[0056] According to the preparation method of the present application, in step (1) and step (2), the solvent is independently selected from one or more of water, ethanol, butanone, ethylene glycol, and 1,4-dioxane.

[0057] According to the preparation method of the present invention, in step (2), the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is 1:(1-4). It can be understood that the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound can be any specific value of 1:1, 1:2, 1:3, 1:4 or any value within the range of 1:(1-4).

[0058] In the present invention, controlling the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound can control the reaction between the polyacrylonitrile fiber and the pyridine compound to be optimal. If the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is too high, the amount of the pyridine compound added to the aminated polyacrylonitrile fiber is low, resulting in insufficient removal of organic chlorine. If the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is too low, the amount of the pyridine compound added to the aminated polyacrylonitrile fiber is large, resulting in insufficient removal of inorganic chlorine.

[0059] According to the preparation method of the present invention, in step (2), the reaction temperature is 40°C-80°C. It can be understood that the reaction temperature can be any specific value of 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or any value within the range of 40°C-80°C.

[0060] Furthermore, according to the preparation method of the present invention, in step (2), the reaction temperature is preferably 50°C-60°C.

[0061] According to the preparation method of the present invention, in step (2), the reaction pressure is 0 MPa-0.2 MPa. It can be understood that the reaction pressure can be any specific value among 0 MPa, 0.1 MPa, 0.2 MPa or any value within the range of 0 MPa-0.2 MPa.

[0062] Furthermore, in step (2), the reaction pressure is preferably 0 MPa-0.1 MPa.

[0063] According to the preparation method of the present invention, in step (2), the reaction time is 2 h to 10 h. It can be understood that the reaction time can be any specific value of 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or any value within the range of 2 h to 10 h.

[0064] According to the preparation method of the present application, in step (2), the drying temperature is 60-90°C, and it can be understood that the drying temperature can be any specific value selected from 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or any value within the range of 60-90°C; the drying time is 12-24 hours, and it can be understood that the drying time can be any specific value selected from 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours or any value within the range of 12-24 hours. The present application does not have specific limitations on the specific drying method, and the conventional drying method in the art can be used, for example, the modified fiber can be first filtered and then dried, or it can be directly dried.

[0065] According to another aspect of the present application, there is also provided a modified fiber for removing chlorine-containing compounds, which is prepared by the above preparation method and has pyridine functional groups and amino functional groups. In the modified fiber of the present application, the pyridine functional groups can effectively adsorb organic chlorine, and the amino functional groups can effectively remove inorganic chlorine.

[0066] In some embodiments, the content of the pyridine functional groups is 0.50-2.1 wt% based on the total weight of the modified fiber, and the content of the amino functional groups is 2.00-6.50 wt%; it can be understood that the content of the pyridine functional groups can be any specific value selected from 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt% or any value within the range of 0.50-2.1 wt%; the content of the amino functional groups can be any specific value selected from 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt% or any value within the range of 2-6.5 wt%. By controlling the content of the pyridine functional groups and the amino functional groups, the present application can further control the removal effect of organic chlorine and inorganic chlorine.

[0067] According to another aspect of the present application, there is also provided a method for using the modified fiber, which comprises the following steps:

[0068] (1) filling the modified fiber into a fixed bed reactor;

[0069] (2) passing the chlorine-containing compound-containing raw material into the fixed bed reactor to remove the chlorine-containing compounds.

[0070] According to the application method of the present application, in step (1), the packing height-diameter ratio of the fixed bed reactor is 2:1-12:1, and it can be understood that the packing height-diameter ratio of the fixed bed reactor can be any specific value of 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1 or any value within the range of 2:1-12:1.

[0071] Further, according to the application method of the present application, in step (1), the packing height-diameter ratio of the fixed bed reactor is preferably 3:1-6:1.

[0072] According to the application method of the present application, in step (2), the volume space velocity of the raw material is 0.1h -1 -80h -1 , and it can be understood that the volume space velocity of the raw material can be any specific value of 0.1h -1 , 1h -1 , 5h -1 , 10h -1 , 15h -1 , 20h -1 , 25h -1 , 30h -1 , 35h -1 , 40h -1 , 45h -1 , 50h -1 , 55h -1 , 60h -1 , 65h -1 , 70h -1 , 75h -1 , 80h -1 or any value within the range of 0.1h -1 -80h -1 .

[0073] Further, according to the application method of the present application, in step (2), the volume space velocity of the raw material is preferably 1h -1 -50h -1 .

[0074] According to the application method of the present application, in step (2), the operating pressure of the fixed bed reactor is 0MPa-0.5MPa, and it can be understood that the operating pressure can be any specific value of 0, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa or any value within the range of 0MPa-0.5MPa.

[0075] Further, according to the application method of the present application, in step (2), the operating pressure of the fixed bed reactor is preferably 0MPa-0.2MPa.

[0076] According to the application method of the present invention, in step (2), the reaction temperature of the fixed bed reactor is 25°C-80°C. It can be understood that the reaction temperature of the fixed bed reactor can be any specific value among 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, and 80°C, or any value within the range of 25°C-80°C.

[0077] Furthermore, according to the application method of the present invention, in step (2), the reaction temperature of the fixed bed reactor is preferably 30°C-55°C.

[0078] In the present invention, fibers are first modified by amination and grafting, and then further reacted with specific pyridine compounds to produce modified fibers with pyridine and amino functional groups. The modified fibers described herein can effectively remove inorganic and organic chlorine from hydrocarbons. The pyridine functional groups effectively adsorb trace amounts of organic chlorine-containing compounds in hydrocarbons, while the amino functional groups react with inorganic chlorine to form ammonium chloride salts, effectively removing inorganic chlorine.

[0079] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the present invention, and are not intended to limit the present invention.

[0080] In the present invention, the chlorine content in the raw material is analyzed and detected using a Compass 4294 portable X-ray fluorescence sulfur analyzer (XRF) and a WC-200 microcomputer salt content analyzer. The WC-200 microcomputer salt content analyzer includes a coulometer, a titration cell, a stirrer, and other units.

[0081] In the present invention, the pyridine functional group content in the modified fiber is calculated by detecting the content of unreacted pyridine raw materials in the reaction solution using gas chromatography; the amino functional group content in the modified fiber is titrated and calculated using a potentiometric titrator.

[0082] In the present application, the chemical raw materials used in the examples and comparative examples are all commercially available. The raw material PAN fiber is produced by Qilu Petrochemical Acrylonitrile Plant, and the brand of polyethyleneimine is E107077.

[0083] Example 1

[0084] 12 g of PAN fiber and 600 g of polyethyleneimine (4% aqueous solution) were weighed and added to a stirred reactor. The mixture was reacted at 120°C under ultrasonic conditions for 3 h. The mixture was then cooled and the fiber was taken out and washed several times in a beaker until the pH of the fiber was neutral. The filtered fiber was dried in a vacuum drying oven at 70°C for 12 h. The temperature was then lowered to obtain aminated polyacrylonitrile fiber A1.

[0085] Take 5g of dry amine polyacrylonitrile fiber A1, 10g of 2-ethanoyl pyridine into a 500ml round bottom flask, add 300ml of ethanol, put the flask into a constant temperature 60℃ water bath reactor for 6h. After the reaction is completed, take out the fiber with tweezers, wash repeatedly with warm water and ethanol at 60-70℃ until the fiber is neutral, put the washed fiber into a 60℃ vacuum drying oven for 8h, and obtain modified fiber A2 for removing chlorine-containing compounds.

[0086] Weigh 5g of modified fiber A2 into a fixed bed reactor, the filling volume is 30ml, the height-diameter ratio is 5:1, and after completion, chlorine-containing diesel oil (chlorine content 15.19ppm) is introduced, the volume space velocity is 15h -1 , and dechlorinated diesel oil is obtained.

[0087] After detection and calculation, the pyridine functional group content in modified fiber A2 is 1.24wt%, the amino functional group content is 4.23wt%; the chlorine content in dechlorinated diesel oil is 0.23ppm, and the chlorine removal rate is 98.55%.

[0088] Example 2

[0089] Put 260ml of 1,4-dioxane into a three-necked flask with magnetic stirring, add weighed 12g of PAN fiber and 40g of triethylenetetramine into the above three-necked flask, and react under the action of ultrasonic wave at a temperature of 120℃ for 6h. After cooling, take out the fiber, put it into a beaker, wash repeatedly until the fiber is neutral, and then filter. Put the filtered amine fiber into a vacuum drying oven for 12h at 70℃, and then cool to obtain amine polyacrylonitrile fiber B1.

[0090] Take 5g of dry amine polyacrylonitrile fiber B1, 10g of 3-formaldehyde pyridine into a 500ml round bottom flask, add 300ml of methanol, and put the flask into a constant temperature 55℃ water bath reactor for 6h. After the reaction is completed, take out the fiber with tweezers, wash repeatedly with warm water and methanol at 60-70℃ until the fiber is neutral, put the washed fiber into a 60℃ vacuum drying oven for 8h, and obtain modified fiber B2 for removing chlorine-containing compounds.

[0091] Weigh 5g of modified fiber B2 into a fixed bed reactor, the filling volume is 30ml, the height-diameter ratio is 4:1, and after completion, chlorine-containing naphtha (chlorine content 38.75ppm) is introduced, the volume space velocity is 10h -1 , and dechlorinated diesel oil is obtained.

[0092] After detection and calculation, the pyridine functional group content in modified fiber B2 is 1.35wt%, the amino functional group content is 4.86wt%; the chlorine content in dechlorinated naphtha is 2.16ppm, and the chlorine removal rate is 94.43%.

[0093] Example 3

[0094] Put 200g water into a three-necked flask with magnetic stirring, put the weighed 12g PAN fiber and 50g triethylene tetramine into the three-necked flask, control the reaction temperature at 90℃ under the action of ultrasonic wave, after stirring for 6h, cool down, take out the fiber, put it into a beaker and wash for several times until the fiber is neutral, then filter, put the filtered fiber into a vacuum drying oven and dry at 70℃ for 12h, then cool down to get the aminated polyacrylonitrile fiber C1.

[0095] Put 5g dry aminated polyacrylonitrile fiber C1 and 10g 2-formaldehyde pyridine into a 500ml round-bottom flask, add 300ml methanol, put the flask into a 60℃ constant temperature water bath reactor and react for 6h, after the reaction, take out the reacted fiber with tweezers, wash it repeatedly with warm water and methanol at 60-70℃ until the fiber is neutral, then put the washed fiber into a 60℃ vacuum drying oven and dry for 8h to get the modified fiber C2 for removing chlorine-containing compounds.

[0096] Put 5g modified fiber C2 into a fixed bed reactor, the filling volume is 30ml and the height-diameter ratio is 6:1, then pass in aviation fuel oil (chlorine content 5.75ppm) at a volume space velocity of 5h-1 to get dechlorinated aviation fuel oil. -1

[0097] After detection and calculation, the content of pyridine functional group in the modified fiber C2 is 1.37wt%, the content of amino functional group is 4.93wt%, and the chlorine content in the dechlorinated aviation fuel oil is 0.24ppm, the chlorine removal rate is 95.83%.

[0098] Example 4

[0099] Put 260g ethylene glycol into a three-necked flask with magnetic stirring, put the weighed 12g PAN fiber and 18g diethylene triamine into the three-necked flask, react at 110℃ for 6h under the action of ultrasonic wave, cool down, take out the fiber, put it into a beaker and wash for several times until the fiber is neutral, then filter, put the filtered fiber into a vacuum drying oven and dry at 70℃ for 12h, then cool down to get the aminated polyacrylonitrile fiber D1.

[0100] Put 5g dry aminated polyacrylonitrile fiber D1 and 19g 2-acetaldehyde pyridine into a 500ml round-bottom flask, add 300ml ethanol, put the flask into a 60℃ constant temperature water bath reactor and react for 6h, after the reaction, take out the reacted fiber with tweezers, wash it repeatedly with warm water and ethanol at 60-70℃ until the fiber is neutral, then put the washed fiber into a 60℃ vacuum drying oven and dry for 8h to get the modified fiber D2 for removing chlorine-containing compounds.

[0101] ​5 g of modified fiber D2 was weighed and loaded into the fixed bed reactor with a filling volume of 30 ml and a height-to-diameter ratio of 3:1. After completion, chlorinated gasoline (chlorine content 8.94 ppm) was introduced at a volume space velocity of 20 h -1 , and obtain dechlorinated gasoline.

[0102] After testing and calculation, the pyridine functional group content in the modified fiber D2 was 2wt%, and the amino functional group content was 2wt%; the chlorine content in the dechlorinated gasoline was 0.28ppm, and the chlorine removal rate was 96.87%.

[0103] Example 5

[0104] 260 g of ethylene glycol was added to a three-necked flask with magnetic stirring, and 12 g of PAN fiber and 60 g of triethylenetetramine were added to the three-necked flask. The mixture was reacted at 110°C for 6 h under the action of ultrasound. The mixture was cooled, and the fiber was taken out and placed in a beaker and washed several times until the pH of the fiber was neutral. The fiber was filtered and dried in a vacuum drying oven at 70°C for 12 h. The temperature was then lowered to obtain the aminated fiber E1.

[0105] Weigh 5g of dry aminated fiber E1 and 6g of 2-acetaldehyde pyridine and put them into a 500ml round-bottom flask, add 300ml of ethanol, and place the flask in a 50℃ constant temperature water bath reactor to react for 6h. After the reaction is completed, use tweezers to take out the reaction fiber, and wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral. Place the washed fiber in a 60℃ vacuum drying oven and dry it for 8h to obtain the modified fiber E2 for removing chlorine-containing compounds.

[0106] 5 g of modified fiber E2 was weighed and loaded into a fixed bed reactor with a filling volume of 30 ml and a height-to-diameter ratio of 4:1. After completion, chlorine-containing naphtha (chlorine content 38.75 ppm) was introduced at a volume space velocity of 10 h -1 , and obtain dechlorinated diesel.

[0107] After testing and calculation, the pyridine functional group content in the modified fiber E2 was 0.7wt%, and the amino functional group content was 6wt%; the chlorine content in the dechlorinated naphtha was 2.21ppm, and the chlorine removal rate was 94.30%.

[0108] Example 6

[0109] 5 g of modified fiber C2 was weighed and loaded into a fixed bed reactor with a filling volume of 30 ml and a height-to-diameter ratio of 5:1. After completion, chlorinated gasoline (chlorine content 9.08 ppm) was introduced at a volume space velocity of 15 h -1 , and obtain dechlorinated gasoline.

[0110] After testing and calculation, the chlorine content in dechlorinated gasoline is 0.21ppm, and the chlorine removal rate is 97.58%.

[0111] Example 7

[0112] 5 g of modified fiber B2 was weighed into a fixed bed reactor with a packing volume of 30 ml and a height-diameter ratio of 5:1, and after completion, chlorine-containing gasoline (chlorine content 9.08 ppm) was introduced at a volume space velocity of 15 h -1 , to obtain dechlorinated gasoline.

[0113] The chlorine content in the dechlorinated gasoline was calculated and detected to be 0.29 ppm, and the chlorine removal rate was 96.81%.

[0114] Comparative Example 1

[0115] This comparative example used unmodified polyacrylonitrile fibers to remove chlorine-containing compounds, and the specific steps were as follows:

[0116] 5 g of unmodified polyacrylonitrile fibers was weighed into a fixed bed reactor with a packing volume of 30 ml and a height-diameter ratio of 5:1, and after completion, chlorine-containing aviation fuel oil (chlorine content 5.75 ppm) was introduced at a volume space velocity of 5 h -1 , to obtain dechlorinated aviation fuel oil.

[0117] The chlorine content in the dechlorinated aviation fuel oil was calculated and detected to be 5.75 ppm, and the chlorine removal rate was 0.

[0118] Comparative Example 2

[0119] This comparative example used polyacrylonitrile fibers modified only by amination to remove chlorine-containing compounds, and the specific steps were as follows:

[0120] 5 g of aminated polyacrylonitrile fiber A1 was weighed into a fixed bed reactor with a packing volume of 30 ml and a height-diameter ratio of 5:1, and after completion, chlorine-containing diesel oil (chlorine content 15.19 ppm) was introduced at a volume space velocity of 15 h -1 , to obtain dechlorinated diesel oil.

[0121] The chlorine content in the dechlorinated diesel oil was calculated and detected to be 8.23 ppm, and the chlorine removal rate was 45.82%.

[0122] Comparative Example 3

[0123] 12 g of PAN fibers and 400 g of polyethyleneimine (0.8% aqueous solution) were weighed into a reaction kettle with stirring, and under the action of ultrasonic waves, the temperature was 120°C for 3 h, then cooled, the fibers were taken out, washed in a beaker until the pH of the fibers was neutral, and then filtered. The aminated fibers were placed in a vacuum drying oven at 70°C for 12 h, and then cooled to obtain aminated polyacrylonitrile fibers F1.

[0124] Take 5 g of dry aminated polyacrylonitrile fiber F1, 10 g of 2-ethenylpyridine into a 500 ml round-bottom flask, add 300 ml of ethanol, and place the flask in a constant-temperature 60°C water bath reactor for 6 h. After the reaction is complete, use tweezers to take out the fiber, and repeatedly wash it with warm water at 60-70°C and ethanol until the fiber is neutral. Place the washed fiber in a 60°C vacuum drying oven for 8 h to obtain modified fiber F2.

[0125] Weigh 5 g of modified fiber F2 into a fixed bed reactor with a packing volume of 30 ml and a height-diameter ratio of 5:1. After completion, pass in chloro-containing diesel oil (chlorine content 15.19 ppm) at a volume space velocity of 15 h -1 to obtain dechlorinated diesel oil.

[0126] After detection and calculation, the pyridine functional group content in the modified fiber F2 is 0.36 wt%, the amino functional group content is 1.79 wt%, the chlorine content in the dechlorinated diesel oil is 7.47 ppm, and the chlorine removal rate is 50.82%.

[0127] Comparative Example 4

[0128] Take 5 g of dry aminated polyacrylonitrile fiber A1, 10 g of 2-methylpyridine into a 500 ml round-bottom flask, add 300 ml of ethanol, and place the flask in a constant-temperature 60°C water bath reactor for 6 h. After the reaction is complete, use tweezers to take out the fiber, and repeatedly wash it with warm water at 60-70°C and ethanol until the fiber is neutral. Place the washed fiber in a 60°C vacuum drying oven for 8 h to obtain modified fiber L.

[0129] Weigh 5 g of modified fiber L into a fixed bed reactor with a packing volume of 30 ml and a height-diameter ratio of 5:1. After completion, pass in chloro-containing diesel oil (chlorine content 15.19 ppm) at a volume space velocity of 10 h -1 to obtain dechlorinated diesel oil.

[0130] After detection and calculation, the pyridine functional group content in the modified fiber L is 0%, the amino functional group content is 4.23 wt%, the chlorine content in the dechlorinated diesel oil is 7.26 ppm, and the chlorine removal rate is 52.21%.

[0131] Comparative Example 5

[0132] Weigh 12 g of PAN fiber, 600 g of polyethyleneimine (4% aqueous solution), and 24 g of 2-ethenylpyridine into a stirred reaction kettle. After reacting at 120°C for 3 h, cool it down, take out the fiber, place it in a beaker, and wash it multiple times until the fiber is neutral. Then, use a suction filter, and place the filtered modified fiber into a vacuum drying oven at 70°C for 12 h. After cooling, obtain modified fiber M.

[0133] 5 g of modified fiber M was weighed and loaded into a fixed bed reactor with a filling volume of 30 ml and a height-to-diameter ratio of 5:1. After completion, chlorinated diesel (chlorine content 15.19 ppm) was introduced at a volume space velocity of 15 h -1 , and obtain dechlorinated diesel.

[0134] After testing and calculation, the content of pyridine functional groups in the modified fiber M was 0.63wt%, and the content of amino functional groups was 0.72wt%; the chlorine content in the dechlorinated diesel was 12.21ppm, and the chlorine removal rate was 19.62%.

[0135] Comparative Example 6

[0136] Weigh 5 g of dry aminated polyacrylonitrile fiber A1 and 10 g of pyridine hydrochloride and place them in a 500 ml round-bottom flask. Add 300 ml of ethanol and place the flask in a constant temperature 60°C water bath reactor for reaction for 6 hours. After the reaction, take out the fiber with tweezers and repeatedly wash it with 60-70°C warm water and ethanol until the fiber becomes neutral. Place the washed fiber in a 60°C vacuum drying oven and dry it for 8 hours to obtain modified fiber N for removing chlorine-containing compounds.

[0137] 5 g of modified fiber N was weighed and loaded into a fixed bed reactor with a filling volume of 30 ml and a height-to-diameter ratio of 5:1. After completion, chlorinated diesel (chlorine content 15.19 ppm) was introduced at a volume space velocity of 10 h -1 , and obtain dechlorinated diesel.

[0138] After testing and calculation, the content of pyridine functional groups in modified fiber N was 0.06wt%, and the content of amino functional groups was 0.72wt%; the chlorine content in dechlorinated diesel was 13.47ppm, and the chlorine removal rate was 11.32%.

[0139] Comparison of the Examples and Comparative Examples shows that the modified polyacrylonitrile fiber obtained according to the preparation method of the present invention is more effective in removing trace chlorine from hydrocarbon substances, with a chlorine removal rate of over 94%. This demonstrates that the modified polyacrylonitrile fiber prepared by the present application has excellent adsorption properties and can effectively remove both organic and inorganic chlorine. Comparative Examples 5 and 6 show that the modified fiber obtained by the method of Comparative Example 5 has a relatively low pyridine content, resulting in a relatively low chlorine removal rate; the modified fiber obtained by the method of Comparative Example 6 has a relatively low amino content, resulting in a relatively low chlorine removal rate.

[0140] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing modified fibers for removing chlorine-containing compounds, characterized in that: The steps include: (1) Mixing polyacrylonitrile fiber, an amine compound, and a solvent, reacting the mixture under ultrasonic conditions, washing the reacted fibers to neutrality, and drying the fibers to obtain aminated polyacrylonitrile fibers; (2) mixing the aminated polyacrylonitrile fiber, the pyridine compound and the solvent described in step (1) to react, washing the fiber after the reaction to neutrality and drying to obtain the modified fiber for removing chlorine-containing compounds; In step (1), the amine compound includes one or more of polyethyleneimine, diethylenetriamine, and triethylenetetramine; In step (1), the mass ratio of the polyacrylonitrile fiber to the amine compound is 1:(1-5); In step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridinecarboxaldehyde, 3-pyridinecarboxaldehyde, and 4-pyridinecarboxaldehyde; In step (2), the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is 1:(1-4).

2. A modified fiber for removing chlorine-containing compounds prepared according to the preparation method according to any one of claim 1, characterized in that: The modified fiber has pyridine functional groups and amino functional groups.

3. The modified fiber for removing chlorine-containing compounds according to claim 2, characterized in that: Based on the total weight of the modified fiber, the content of the pyridine functional group is 0.50 wt%-2.1 wt%, and the content of the amino functional group is 2.00 wt%-6.50 wt%.

4. A method for applying the modified fiber according to any one of claims 2 or 3, characterized in that: It is used to remove chlorine-containing compounds from hydrocarbon substances, and specifically includes the following steps: (1) filling the modified fiber into a fixed bed reactor; (2) The raw material containing chlorine compounds is passed into a fixed bed reactor to remove the chlorine compounds.

5. The application method according to claim 4, characterized in that: In step (1), the filling height-to-diameter ratio of the fixed bed reactor is 2:1-12:

1.

6. The application method according to claim 4, characterized in that: In step (2), the volumetric space velocity of the raw material is 0.1h -1 -80h -1 The operating pressure of the fixed bed reactor is 0MPa-0.5MPa, and the reaction temperature of the fixed bed reactor is 25℃-80℃.