Modified fiber for removing chlorine-containing compounds as well as preparation method and application of modified fiber

Abstract

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

Description

Technical Field

[0001] The invention belongs to the technical field of removing chlorine-containing compounds, and particularly relates to a modified fiber for removing chlorine-containing compounds, and a preparation method and application thereof. Background Art

[0002] The main components of gasoline, naphtha, aviation fuel oil and diesel are aliphatic hydrocarbons and cycloalkanes, and contain trace amounts of inorganic chlorine and organic chlorine. Chlorine has a high electron affinity and is easy to react with many substances. It also migrates 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 chlorine compounds in the raw materials must be strictly controlled to meet the process and product performance requirements.

[0003] At present, the widely used dechlorination technology in industry is hydrodechlorination, but a specific catalyst is required in the hydrodechlorination process. The generated HCl has high requirements on the equipment material due to its strong corrosiveness. It is also necessary to add an alkali washing method to remove it. The process is complicated and the energy consumption is high. In addition, the dechlorinating agent used in catalytic hydrogenation has low chlorine removal rate and catalyst regeneration is difficult. Other existing dechlorination technologies also have a series of problems such as high energy consumption, low chlorine removal rate, difficult regeneration and the process is not green, low-carbon and environmentally friendly. Patent CN103611566A discloses a catalyst for removing organic chlorine from high-chlorine oil products and a preparation method thereof. The catalyst prepared by the method has high hydrodechlorination activity and stability, but is only suitable for treating light oil products such as naphtha with high chlorine content. US5928500A discloses an adsorbent and a regeneration method for removing chlorides from hydrocarbon raw materials. The disadvantage of the adsorbent is that it is frequently regenerated, and the chloride removal effect decreases rapidly after the contact time with the raw material exceeds 16 hours. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a modified fiber for removing chlorine-containing compounds, which has the characteristics of good adsorption performance, effective removal of both organic chlorine and inorganic chlorine, no pollution, simple process and convenient operation; the present invention 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 applications.

[0005] In order to achieve the above object, according to one aspect of the present invention, a method for preparing modified fiber for removing chlorine-containing compounds is provided, comprising the following steps: (1) polyacrylonitrile fiber (PAN fiber for short), an amine compound and a solvent are mixed and reacted under ultrasonic conditions, and the reacted fiber is washed to neutrality and dried to obtain aminated polyacrylonitrile fiber; (2) The aminated polyacrylonitrile fiber, pyridine compound and solvent described in step (1) are mixed and reacted, and the fibers after the reaction are washed to neutrality and dried to obtain the modified fiber for removing chlorine-containing compounds.

[0006] In some embodiments, in step (1), the amine compound includes one or more of polyethyleneimine, diethylenetriamine, and triethylenetetramine.

[0007] In some embodiments, in step (1), the mass ratio of the polyacrylonitrile fiber to the amine compound is 1:(1-5).

[0008] In some embodiments, in step (1), the reaction temperature is 60°C-150°C.

[0009] In some embodiments, in step (1), the reaction pressure is 0 MPa-0.5 MPa.

[0010] In some embodiments, in step (1), the reaction time is 2h-24h.

[0011] In some embodiments, in step (1), the drying temperature is 60°C-90°C, and the drying time is 12h-24h.

[0012] In some embodiments, in step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridinecarboxaldehyde, 3-pyridinecarboxaldehyde, and 4-pyridinecarboxaldehyde.

[0013] In some embodiments, 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.

[0014] In some embodiments, in step (2), the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is 1:(1-4).

[0015] In some embodiments, in step (2), the reaction temperature is 40°C-80°C.

[0016] In some embodiments, in step (2), the reaction pressure is 0 MPa-0.2 MPa.

[0017] In some embodiments, in step (2), the reaction time is 2h-10h.

[0018] In some embodiments, in step (2), the drying temperature is 60°C-90°C, and the drying time is 12h-24h.

[0019] According to another aspect of the present invention, there is also provided a modified fiber for removing chlorine-containing compounds prepared according to the above preparation method, wherein the modified fiber has a pyridine functional group and an amino functional group.

[0020] In some embodiments, 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 %.

[0021] According to another aspect of the present invention, there is also provided an application method of the modified fiber for removing chlorine-containing compounds from hydrocarbon substances, which specifically comprises the following steps: (1) loading the modified fiber into a fixed bed reactor; (2) The raw material containing chlorine compounds is introduced into a fixed bed reactor to remove the chlorine compounds.

[0022] In some embodiments, in step (1), the filling height-to-diameter ratio of the fixed bed reactor is 2:1-12:1.

[0023] In some embodiments, in step (2), the volumetric space velocity of the raw material is 0.1h -1 -80h -1 .

[0024] In some embodiments, in step (2), the operating pressure of the fixed bed reactor is 0 MPa-0.5 MPa.

[0025] In some embodiments, in step (2), the reaction temperature of the fixed bed reactor is 25°C-80°C.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) The modified fiber for removing chlorine-containing compounds described in the present invention can be used to remove trace chlorine-containing compounds in hydrocarbon substances. The modified fiber described in the present invention contains a specific content of amino functional groups and pyridine functional groups, and has the characteristics of good adsorption performance, effective removal of both organic chlorine and inorganic chlorine, no pollution, simple process and convenient operation.

[0027] (2) The preparation method of the present invention has a simple preparation process, is easy to operate and has good repeatability, and is suitable for large-scale industrial application.

[0028] (3) The present invention adopts a process combining synthetic modified new materials with an adsorption fixed bed, and effectively removes trace amounts of chlorine from hydrocarbon substances by designing synthetic modified grafted PAN fibers and optimizing the adsorption conditions of the fixed bed. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0030] Herein, trace amounts refer to chlorine-containing compounds in hydrocarbon substances in an amount of 1 ppm to 50 ppm.

[0031] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0032] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0033] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0034] The present invention provides a modified fiber for removing chlorine-containing compounds, which has the characteristics of good adsorption performance, effective removal of both organic chlorine and inorganic chlorine, no pollution, simple process and convenient operation; the present invention 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.

[0035] In order to achieve the above object, according to one aspect of the present invention, a method for preparing a modified fiber for removing chlorine-containing compounds is provided, comprising the following steps: (1) mixing polyacrylonitrile fiber, an amine compound and a solvent, reacting them under ultrasonic conditions, washing the reacted fiber to neutrality and drying it to obtain aminated polyacrylonitrile fiber; (2) The aminated polyacrylonitrile fiber, pyridine compound and solvent described in step (1) are mixed and reacted, and the fibers after the reaction are washed to neutrality and dried to obtain the modified fiber for removing chlorine-containing compounds.

[0036] 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 after modification.

[0037] 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 found that by reacting the amine compound of the present invention with polyacrylonitrile fiber, a grafted modified fiber can be obtained, and 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 in hydrocarbon substances.

[0038] 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 can be 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 a suitable range, the reaction of the polyacrylonitrile fiber and the amine compound can be maximized while optimizing the economic cost.

[0039] 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 of 30kHz, 35kHz, 40kHz, 45kHz, 50kHz, 55kHz, 60kHz or any value within the range of 30kHz-60kHz.

[0040] 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.

[0041] Furthermore, according to the preparation method of the present invention, in step (1), the reaction temperature is preferably 70°C-110°C.

[0042] 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.

[0043] Furthermore, according to the preparation method of the present invention, in step (1), the reaction pressure is preferably 0 MPa-0.2 MPa.

[0044] According to the preparation method of the present invention, in step (1), the reaction time is 2h-24h. 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.

[0045] In the present invention, in step (1), there is no particular limitation on the washing method of the fibers after the reaction, and conventional washing methods in the art may be used, for example, washing with deionized water or a mixed solution of deionized water and alcohol.

[0046] According to the preparation method of the present invention, in step (1), the drying temperature is 60°C-90°C. It is understood that the drying temperature can be any specific value of 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or any value within the range of 60°C-90°C; the drying time is 12h-24h. It is understood that the drying time can be any specific value of 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h or any value within the range of 12h-24h. The present invention has no specific restrictions on the specific drying method, and conventional drying methods in the art can be used, such as suction filtration followed by drying, or direct drying.

[0047] According to the preparation method of the present invention, in step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridinecarboxaldehyde, 3-pyridinecarboxaldehyde, and 4-pyridinecarboxaldehyde.

[0048] In the present invention, polyacrylonitrile fiber is modified by using specific types of pyridine compounds and amine compounds, and the obtained modified fiber contains specific contents of amino functional groups and pyridine functional groups; the pyridine functional group can effectively adsorb trace organic chlorides in hydrocarbon substances, and the amino functional group can form ammonium chloride salts with inorganic chlorine, thereby effectively removing inorganic chlorine.

[0049] According to the preparation method of the present invention, 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.

[0050] 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).

[0051] In the present invention, the mass ratio of the aminated polyacrylonitrile fiber and the pyridine compound is controlled, so that the polyacrylonitrile fiber and the pyridine compound can be controlled to react well. If the mass ratio of the aminated polyacrylonitrile fiber and 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 and 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.

[0052] 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.

[0053] Furthermore, according to the preparation method of the present invention, in step (2), the reaction temperature is preferably 50°C-60°C.

[0054] 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.

[0055] Furthermore, in step (2), the reaction pressure is preferably 0 MPa-0.1 MPa.

[0056] According to the preparation method of the present invention, in step (2), the reaction time is 2h-10h. It can be understood that the reaction time can be any specific value of 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or any value within the range of 2h-10h.

[0057] According to the preparation method of the present invention, in step (2), the drying temperature is 60°C-90°C. It is understood that the drying temperature can be any specific value of 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or any value within the range of 60°C-90°C; the drying time is 12h-24h. It is understood that the drying time can be any specific value of 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h or any value within the range of 12h-24h. The present invention has no specific restrictions on the specific drying method, and conventional drying methods in the art can be used, such as suction filtration followed by drying, or direct drying.

[0058] According to another aspect of the present invention, there is also provided a modified fiber for removing chlorine-containing compounds prepared according to the above preparation method, wherein the modified fiber has a pyridine functional group and an amino functional group. In the modified fiber of the present invention, the pyridine functional group can effectively adsorb organic chlorine, and the amino functional group can effectively remove inorganic chlorine.

[0059] In some embodiments, based on the total weight of the modified fiber, the content of the pyridine functional group is 0.50wt%-2.1wt%, and the content of the amino functional group is 2.00wt%-6.50wt%; it can be understood that the content of the pyridine functional group can be any specific value among 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2.0wt%, 2.1wt%, or any value within the range of 0.50wt%-2.1wt%; the content of the amino functional group can be any specific value among 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, or any value within the range of 2wt%-6.5wt%. The present application can further control the removal effect of organic chlorine and inorganic chlorine by controlling the content of pyridine functional group and amino functional group.

[0060] According to another aspect of the present invention, there is also provided a method for applying the modified fiber, comprising the following steps: (1) loading the modified fiber into a fixed bed reactor; (2) The raw material containing chlorine compounds is introduced into a fixed bed reactor to remove the chlorine compounds.

[0061] According to the application method of the present invention, in step (1), the filling height-to-diameter ratio of the fixed bed reactor is 2:1-12:1. It can be understood that the filling height-to-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.

[0062] Furthermore, according to the application method of the present invention, in step (1), the filling height-to-diameter ratio of the fixed bed reactor is preferably 3:1-6:1.

[0063] According to the application method of the present invention, in step (2), the volume space velocity of the raw material is 0.1h -1 -80h -1 It is understood that the volumetric space velocity of the raw material can be 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 Any specific value or 0.1h -1 -80h -1 Any value in the range.

[0064] Furthermore, according to the application method of the present invention, in step (2), the volume space velocity of the raw material is preferably 1h -1 -50h -1 .

[0065] According to the application method of the present invention, in step (2), the operating pressure of the fixed bed reactor is 0 MPa-0.5 MPa. It can be understood that the operating 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.

[0066] Furthermore, according to the application method of the present invention, in step (2), the operating pressure of the fixed bed reactor is preferably 0 MPa-0.2 MPa.

[0067] 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 of 25°C, 30°C, 35°C, 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 25°C-80°C.

[0068] 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.

[0069] In the present invention, the fiber is first modified by amination grafting, and then further reacted with a specific pyridine compound to prepare a modified fiber having a pyridine functional group and an amino functional group. The modified fiber of the present application can effectively remove inorganic chlorine and organic chlorine in hydrocarbons. The pyridine functional group can effectively adsorb trace organic chlorine-containing compounds in hydrocarbon substances, and the amino functional group can form ammonium chloride salt with inorganic chlorine, thereby achieving effective removal of inorganic chlorine.

[0070] 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 content of the present invention by way of example, and are not intended to limit the present invention.

[0071] 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 microcomputer and other units.

[0072] In the present invention, the content of pyridine functional groups in the modified fiber is calculated by detecting the content of unreacted pyridine raw materials in the reaction solution using gas chromatography; the content of amino functional groups in the modified fiber is titrated and calculated using a potentiometric titrator.

[0073] 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.

[0074] Example 1 12 g of PAN fiber and 600 g of polyethyleneimine (4% aqueous solution) were weighed and added into a stirred reactor. The mixture was reacted at 120°C for 3 h under the action of ultrasound. 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 fiber was filtered and the filtered aminated fiber was dried in a vacuum drying oven at 70°C for 12 h. The aminated polyacrylonitrile fiber A1 was obtained by cooling.

[0075] Weigh 5g of dry aminated polyacrylonitrile fiber A1 and 10g of 2-acetaldehyde pyridine and put them into a 500ml round-bottom flask, add 300ml of ethanol, and put the flask into a constant temperature 60℃ water bath reactor to react for 6h. After the reaction, take out the fiber with tweezers, and wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral. Put the washed fiber into a 60℃ vacuum drying oven and dry it for 8h to obtain the modified fiber A2 for removing chlorine-containing compounds.

[0076] Weigh 5g of modified fiber A2 and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) is introduced into the fixed bed reactor. The volumetric space velocity is 15h -1 , and obtain dechlorinated diesel.

[0077] After testing and calculation, the content of pyridine functional groups in the modified fiber A2 was 1.24wt%, and the content of amino functional groups was 4.23wt%; the chlorine content in the dechlorinated diesel was 0.23ppm, and the chlorine removal rate was 98.55%.

[0078] Example 2 Add 260 ml of 1,4-dioxane into a three-necked flask with magnetic stirring, and add weighed 12 g of PAN fiber and 40 g of triethylenetetramine into the above three-necked flask. Under the action of ultrasound, the temperature is 120°C, react for 6 hours, cool down, take out the fiber, put it into a beaker and wash it several times until the pH of the fiber is neutral, filter it, put the filtered aminated fiber into a vacuum drying oven at 70°C and dry it for 12 hours, and cool it to obtain aminated polyacrylonitrile fiber B1.

[0079] Weigh 5g of dry aminated polyacrylonitrile fiber B1 and 10g of 3-formaldehyde pyridine into a 500ml round-bottom flask, add 300ml of methanol, and place the flask in a 55℃ constant temperature water bath reactor for 6h. After the reaction, take out the fiber with tweezers, wash it repeatedly with 60-70℃ warm water and methanol until the fiber is neutral, and dry the washed fiber in a 60℃ vacuum drying oven for 8h to obtain the modified fiber B2 for removing chlorine-containing compounds.

[0080] Weigh 5g of modified fiber B2 and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 4:1. After completion, chlorine-containing naphtha (chlorine content 38.75ppm) is introduced at a volume space velocity of 10h -1 , and obtain dechlorinated diesel.

[0081] After testing and calculation, the content of pyridine functional groups in the modified fiber B2 was 1.35wt%, and the content of amino functional groups was 4.86wt%; the chlorine content in the dechlorinated naphtha was 2.16ppm, and the chlorine removal rate was 94.43%.

[0082] Example 3 200g of water was added into a three-necked flask with magnetic stirring, and 12g of PAN fiber and 50g of triethylenetetramine were weighed into the three-necked flask. The reaction temperature was controlled at 90°C under the action of ultrasound. After stirring for 6 hours, the temperature was lowered 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 placed in a vacuum drying oven and dried at 70°C for 12 hours, and the temperature was lowered to obtain the aminated polyacrylonitrile fiber C1.

[0083] Weigh 5g of dry aminated polyacrylonitrile fiber C1 and 10g of 2-formaldehyde pyridine and put them into a 500ml round-bottom flask, add 300ml of methanol, and put the flask into a 60℃ constant temperature water bath reactor to react for 6h. After the reaction, take out the reaction fiber with tweezers, and wash it repeatedly with 60-70℃ warm water and methanol until the fiber is neutral. Put the washed fiber into a 60℃ vacuum drying oven and dry it for 8h to obtain the modified fiber C2 for removing chlorine-containing compounds.

[0084] Weigh 5g of modified fiber C2 and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 6:1. After completion, aviation fuel oil (chlorine content 5.75ppm) was introduced into the reactor with a volume space velocity of 5h -1 , and obtain dechlorinated aviation fuel oil.

[0085] After testing and calculation, the content of pyridine functional groups in the modified fiber C2 was 1.37wt%, and the content of amino functional groups was 4.93wt%; the chlorine content in the dechlorinated aviation fuel oil was 0.24ppm, and the chlorine removal rate was 95.83%.

[0086] Example 4 Add 260g of ethylene glycol into a three-necked flask with magnetic stirring, add weighed 12g of PAN fiber and 18g of diethylenetriamine into the three-necked flask, react at 110°C for 6h under the action of ultrasound, cool down, take out the fiber, put it into a beaker and wash it several times until the pH of the fiber is neutral, filter it, put it into a vacuum drying oven and dry it at 70°C for 12h, and cool it down to obtain aminated polyacrylonitrile fiber D1.

[0087] Weigh 5g of dry aminated polyacrylonitrile fiber D1 and 19g of 2-acetaldehyde pyridine and put them into a 500ml round-bottom flask, add 300ml of ethanol, and put the flask into a 60℃ constant temperature water bath reactor to react for 6h. After the reaction, take out the reaction fiber with tweezers, and wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral. Put the washed fiber into a 60℃ vacuum drying oven and dry it for 8h to obtain the modified fiber D2 for removing chlorine-containing compounds.

[0088] Weigh 5g of modified fiber D2 and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 3:1. After completion, chlorinated gasoline (chlorine content 8.94ppm) was introduced at a volume space velocity of 20h -1 , and obtain dechlorinated gasoline.

[0089] After testing and calculation, the content of pyridine functional groups in the modified fiber D2 was 2wt%, and the content of amino functional groups was 2wt%; the chlorine content in the dechlorinated gasoline was 0.28ppm, and the chlorine removal rate was 96.87%.

[0090] Example 5 Add 260g of ethylene glycol into a three-necked flask with magnetic stirring, add weighed 12g of PAN fiber and 60g of triethylenetetramine into the three-necked flask, react at 110°C for 6h under the action of ultrasound, cool down, take out the fiber, put it into a beaker and wash it several times until the pH of the fiber is neutral, filter it, put the filtered fiber into a vacuum drying oven at 70°C for 12h, and cool it to obtain the aminated fiber E1.

[0091] 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 put the flask into a 50℃ constant temperature water bath reactor to react for 6h. After the reaction, use tweezers to take out the reaction fiber, and wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral. Put the washed fiber into a 60℃ vacuum drying oven and dry it for 8h to obtain the modified fiber E2 for removing chlorine-containing compounds.

[0092] Weigh 5g of modified fiber E2 and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 4:1. After completion, chlorine-containing naphtha (chlorine content 38.75ppm) was introduced at a volume space velocity of 10h -1 , and obtain dechlorinated diesel.

[0093] After testing and calculation, the content of pyridine functional groups in the modified fiber E2 was 0.7wt%, and the content of amino functional groups was 6wt%; the chlorine content in the dechlorinated naphtha was 2.21ppm, and the chlorine removal rate was 94.30%.

[0094] Example 6 Weigh 5g of modified fiber C2 and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated gasoline (chlorine content 9.08ppm) is introduced and the volume space velocity is 15h -1 , and obtain dechlorinated gasoline.

[0095] After testing and calculation, the chlorine content in dechlorinated gasoline is 0.21ppm, and the chlorine removal rate is 97.58%.

[0096] Example 7 Weigh 5g of modified fiber B2 and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated gasoline (chlorine content 9.08ppm) is introduced and the volume space velocity is 15h -1 , and obtain dechlorinated gasoline.

[0097] After testing and calculation, the chlorine content in dechlorinated gasoline is 0.29ppm, and the chlorine removal rate is 96.81%.

[0098] Comparative Example 1 This comparative example uses unmodified polyacrylonitrile fiber to remove chlorine-containing compounds, and the specific steps are as follows: Weigh 5g of unmodified polyacrylonitrile fiber and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated aviation fuel oil (chlorine content 5.75ppm) is introduced into the fixed bed reactor at a volume space velocity of 5h -1 , and obtain dechlorinated aviation fuel oil.

[0099] After testing and calculation, the chlorine content in dechlorinated aviation fuel is 5.75ppm and the chlorine removal rate is 0.

[0100] Comparative Example 2 This comparative example uses polyacrylonitrile fiber that has been modified by amination only to remove chlorine-containing compounds, and the specific steps are as follows: Weigh 5g of aminated polyacrylonitrile fiber A1 and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) is introduced into the reactor at a volume space velocity of 15h -1 , and obtain dechlorinated diesel.

[0101] After testing and calculation, the chlorine content in dechlorinated diesel is 8.23ppm, and the chlorine removal rate is 45.82%.

[0102] Comparative Example 3 12 g of PAN fiber and 400 g of polyethyleneimine (0.8% aqueous solution) were weighed and added into a stirred reactor. The mixture was reacted at 120°C for 3 h under the action of ultrasound. The fiber was then cooled and taken out. The fiber was washed several times in a beaker until the pH of the fiber was neutral. The fiber was filtered and the filtered aminated fiber was dried in a vacuum drying oven at 70°C for 12 h. The aminated polyacrylonitrile fiber F1 was obtained by cooling.

[0103] Weigh 5g of dry aminated polyacrylonitrile fiber F1 and 10g of 2-acetaldehyde pyridine and put them into a 500ml round-bottom flask, add 300ml of ethanol, and put the flask into a constant temperature 60℃ water bath reactor to react for 6h. After the reaction, take out the fiber with tweezers, wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral, and put the washed fiber into a 60℃ vacuum drying oven to dry for 8h to obtain modified fiber F2.

[0104] Weigh 5g of modified fiber F2 and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) is introduced and the volumetric space velocity is 15h -1 , and obtain dechlorinated diesel.

[0105] After testing and calculation, the content of pyridine functional groups in the modified fiber F2 was 0.36wt%, and the content of amino functional groups was 1.79wt%; the chlorine content in the dechlorinated diesel was 7.47ppm, and the chlorine removal rate was 50.82%.

[0106] Comparative Example 4 Weigh 5g of dry aminated polyacrylonitrile fiber A1 and 10g of 2-methylpyridine and put them into a 500ml round-bottom flask, add 300ml of ethanol, and put the flask into a constant temperature 60℃ water bath reactor to react for 6h. After the reaction, take out the fiber with tweezers, and wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral. Put the washed fiber into a 60℃ vacuum drying oven and dry it for 8h to obtain modified fiber L.

[0107] Weigh 5g of modified fiber L and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) is introduced at a volume space velocity of 10h -1 , and obtain dechlorinated diesel.

[0108] After testing and calculation, the pyridine functional group content in the modified fiber L was 0%, the amino functional group content was 4.23wt%, the chlorine content in the dechlorinated diesel was 7.26ppm, and the chlorine removal rate was 52.21%.

[0109] Comparative Example 5 12 g of PAN fiber, 600 g of polyethyleneimine (4% aqueous solution) and 24 g of 2-acetaldehyde pyridine were added to a stirred reactor, reacted at 120°C for 3 h, cooled, the fiber was taken out, put into a beaker and washed several times until the pH of the fiber was neutral, filtered, and the filtered modified fiber was placed in a vacuum drying oven at 70°C for 12 h and dried, and cooled to obtain modified fiber M.

[0110] Weigh 5g of modified fiber M and load it into the fixed bed reactor with a filling volume of 30ml and a height-to-diameter ratio of 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) was introduced at a volume space velocity of 15h -1 , and obtain dechlorinated diesel.

[0111] 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%.

[0112] Comparative Example 6 Weigh 5g of dry aminated polyacrylonitrile fiber A1 and 10g of pyridine hydrochloride and put them into a 500ml round-bottom flask, add 300ml of ethanol, and put the flask into a constant temperature 60℃ water bath reactor to react for 6h. After the reaction, take out the fiber with tweezers, wash it repeatedly with 60-70℃ warm water and ethanol until the fiber is neutral, and put the washed fiber into a 60℃ vacuum drying oven to dry for 8h to obtain modified fiber N for removing chlorine-containing compounds.

[0113] Weigh 5g of modified fiber N and load it into the fixed bed reactor. The filling volume is 30ml and the height-to-diameter ratio is 5:1. After completion, chlorinated diesel (chlorine content 15.19ppm) is introduced and the volume space velocity is 10h -1 , and obtain dechlorinated diesel.

[0114] 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%.

[0115] By comparing the examples and comparative examples, it can be seen that the modified polyacrylonitrile fiber obtained by the preparation method of the present invention has a more obvious effect on removing trace chlorine in hydrocarbon substances, and the chlorine removal rate can reach more than 94%, indicating that the modified polyacrylonitrile fiber prepared by the present application has good adsorption performance and can remove both organic chlorine and inorganic chlorine very well. It can be seen from comparative examples 5 and 6 that the modified fiber obtained by the method of comparative example 5 has a low pyridine content, so the chlorine removal rate is low; the modified fiber obtained by the method of comparative example 6 has a low amino content, so the chlorine removal rate is low.

[0116] 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 protection scope 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 them under ultrasonic conditions, washing the reacted fiber to neutrality and drying it to obtain aminated polyacrylonitrile fiber; (2) The aminated polyacrylonitrile fiber, pyridine compound and solvent described in step (1) are mixed and reacted, and the fibers after the reaction are washed to neutrality and dried to obtain the modified fiber for removing chlorine-containing compounds.

2. The method for preparing modified fiber for removing chlorine-containing compounds according to claim 1, characterized in that: In step (1), the amine compound includes one or more of polyethyleneimine, diethylenetriamine, and triethylenetetramine.

3. The method for preparing modified fiber for removing chlorine-containing compounds according to claim 1, characterized in that: In step (1), the mass ratio of the polyacrylonitrile fiber to the amine compound is 1:(1-5).

4. The method for preparing modified fiber for removing chlorine-containing compounds according to claim 1, characterized in that: In step (2), the pyridine compound includes one or more of 2-acetaldehyde pyridine, 2-pyridinecarboxaldehyde, 3-pyridinecarboxaldehyde, and 4-pyridinecarboxaldehyde.

5. The method for preparing modified fiber for removing chlorine-containing compounds according to claim 1, characterized in that: In step (2), the mass ratio of the aminated polyacrylonitrile fiber to the pyridine compound is 1:(1-4).

6. A modified fiber for removing chlorine-containing compounds prepared according to the preparation method according to any one of claims 1 to 5, characterized in that: The modified fiber has a pyridine functional group and an amino functional group.

7. The modified fiber for removing chlorine-containing compounds according to claim 6, characterized in that: Based on the total weight of the modified fiber, the content of the pyridine functional group is 0.50wt%-2.1wt%, and the content of the amino functional group is 2.00wt%-6.50wt%.

8. A method for using the modified fiber according to any one of claims 6 or 7, characterized in that: Used to remove chlorine-containing compounds in hydrocarbon substances, specifically including the following steps: (1) loading the modified fiber into a fixed bed reactor; (2) The raw material containing chlorine compounds is introduced into a fixed bed reactor to remove the chlorine compounds.

9. The application method according to claim 8, characterized in that: In step (1), the filling height-to-diameter ratio of the fixed bed reactor is 2:1-12:

1.

10. The application method according to claim 8, 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℃.