Compositions for treating waste plastic oil, their applications, and methods for removing impurities from waste plastic oil.

Abstract

This invention relates to the field of waste plastic oil recycling, and discloses a composition for treating waste plastic oil, its application, and a method for removing impurities from waste plastic oil. Based on the total amount of the composition, it contains the following components, stored independently or in combination: 30-45 wt% of a carboxylic acid polymer, 5-10 wt% of hydroxamic acid, 5-20 wt% of a polyether imidazoline compound, and 5-10 wt% of a demulsifier; wherein the polyether imidazoline compound is an alkylphenol resin polyether imidazoline. Using the composition provided by this invention to treat waste plastic oil, the removal rates of iron and calcium are 58% and 65% or more, respectively, and the removal rate of chlorine is 40% or more, reaching a maximum of 45.5%, exhibiting good demetallization and dechlorination effects. Furthermore, in a preferred embodiment, the reaction conditions are also more moderate.

Description

Technical Field

[0001] This invention relates to the field of waste plastic oil recycling, specifically to compositions for treating waste plastic oil, their applications, and methods for removing impurities from waste plastic oil. Background Technology

[0002] While plastics bring convenience to human society, they also create many environmental problems, becoming "white pollution" and harming human health. Statistics show that worldwide, over 60% of waste plastics end up in landfills and incineration because they cannot be properly utilized.

[0003] Common waste plastics include: polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), polycarbonate (PC), polylactic acid (PA), nylon, fiberglass (FRP), and polylactic acid film (BOPLA).

[0004] Waste plastics can be converted into recycled oil, known as plastic oil or waste plastic oil, under high temperatures or with a catalyst. Plastic oil can be used as fuel or a chemical feedstock, or, under appropriate processing conditions, it can be converted into high-value-added products such as diesel, low-carbon olefins, and high-octane gasoline. Preparing plastic oil from waste plastics and then using it as a raw material to manufacture high-value-added products represents a promising technology for the chemical recycling of waste plastics, attracting widespread attention both domestically and internationally.

[0005] Methods for pyrolysis and oilification of waste plastics include thermal pyrolysis, catalytic pyrolysis, thermal pyrolysis-catalytic reforming, and catalytic pyrolysis-catalytic reforming. The catalysts used include solid acid catalysts, alkali metal catalysts (such as CaO, BaO, Al2O3), and molecular sieves (ZSM-5).

[0006] Because there are many types of waste plastics and they contain a variety of additives, the impurity content in plastic oil is generally high, with the main impurities including chlorine and metals.

[0007] Metals such as calcium and iron in plastic oil have a significant impact on subsequent processing. These metals mainly come from the catalysts used in the catalytic cracking of plastics. Metals such as calcium and iron can exist in the form of fine particulate matter or combine with acidic substances in plastic oil to form oil-soluble compounds.

[0008] Chlorine in plastic oils has a significant impact on subsequent processing. The chlorine in plastic oils mainly comes from HCl released during the decomposition of PVC. Literature reports that PVC begins dechlorination at 200℃ and completes dechlorination before 350℃. HCl can add to other olefins or alkynes produced during cracking to form chlorinated alkanes or chlorinated olefins. HCl can also react with PET decomposition products to form chlorinated esters. These chlorinated hydrocarbons and esters release HCl again during plastic oil processing, causing equipment corrosion and salt buildup. Therefore, many plastic oil manufacturing companies have strict requirements on the PVC and PET content of waste plastic raw materials. However, due to the wide availability of waste plastics and the difficulty of sorting them, the actual plastic oils produced still have excessive chlorine content. For example, some companies produce plastic oils with a chlorine content of 0.25%-0.48%, which has a significant impact on subsequent processing.

[0009] There is currently no good method for removing impurities such as metals and chlorine from plastic oils; we can only refer to the methods used for dechlorination of distillate oils and demetallization of crude oils.

[0010] CN101392184A discloses a method for removing metals from hydrocarbon oil using phytic acid. The method includes: thoroughly mixing hydrocarbon oil, phytic acid, a demulsifier, and water; separating the oil phase and the aqueous phase; and extracting the metals from the oil phase into the aqueous phase for removal. The molar ratio of phytic acid to calcium in the feed oil is 0.01-10:1 to achieve the removal of metals such as calcium, iron, magnesium, and manganese from the hydrocarbon oil.

[0011] CN101314728A discloses a method for removing iron from hydrocarbon feedstock oil. This method uses an iron-removing agent prepared by mixing nitrogen-containing compounds with organic acids, which has a stronger iron ion chelating ability and can achieve better iron removal effect in a shorter reaction time and at a lower reaction temperature.

[0012] CN1760340A and CN1760341A respectively disclose methods for removing metals from hydrocarbon oils using carboxylic acid homopolymers or carboxylic acid copolymers. These methods use unsaturated carboxylic acid homopolymers or unsaturated carboxylic acid copolymers as demetallizing agents for hydrocarbon oils. They are particularly effective in removing metals such as calcium and iron, which exist in the form of naphthenates, from hydrocarbon oils. They are characterized by small dosage and high removal efficiency, and are applicable to hydrocarbon oils containing calcium exceeding the permissible limit.

[0013] Methods for demetallizing crude oil are relatively mature, and there are many existing technologies. However, the forms in which metals such as calcium and iron exist in plastic oils differ from those in crude oils. These metals originate from catalysts added during the pyrolysis of plastics to produce oil. During pyrolysis, acidic substances from the plastic oil are adsorbed onto the surface, becoming oil-soluble metals. Using a simulated electro-desalting process with a demetallizing agent results in a low metal removal rate. Therefore, methods for demetallizing crude oils are not applicable to the removal of metals from plastic oils.

[0014] Currently, the main methods for removing organochlorines include catalytic hydrogenation, advanced oxidation, metal reduction, nucleophilic substitution, electrochemical dechlorination, and biological dechlorination. Among these methods, catalytic hydrogenation has the highest dechlorination efficiency (greater than 90%), while other methods have relatively low removal rates (less than 40%).

[0015] Catalytic hydrogenation involves the reaction of hydrogen with organic chlorides on the surface of a catalyst to produce HCl and the corresponding hydrocarbons. CN104492480A and CN111171865A disclose methods for catalytic hydrodechlorination, but these methods involve high reaction temperatures (above 300℃) and pressures (above 2.5MPa), requiring high-temperature, high-pressure equipment, resulting in high equipment investment and operating costs. Furthermore, the HCl produced during catalytic hydrodechlorination can cause equipment corrosion, seriously affecting operational safety. Summary of the Invention

[0016] The purpose of this invention is to overcome the problem that existing methods for removing impurities from waste plastic oil have poor removal effects on metals and chlorine.

[0017] To achieve the above objectives, a first aspect of the present invention provides a composition for treating waste plastic oil, wherein, based on the total amount of the composition, the composition contains the following components, which are stored individually or in combination:

[0018] 30-45 wt% of a carboxylic acid polymer, 5-10 wt% of hydroxamic acid, 5-20 wt% of a polyether imidazoline compound, and 5-10 wt% of a demulsifier; wherein the polyether imidazoline compound is an alkylphenol resin polyether imidazoline having the general formula structure shown in Formula I:

[0019]

[0020] In the formula, R is nonyl or octyl; a is 2-10; x is 1-2; y is 5-8.

[0021] A second aspect of the present invention provides the use of the composition described in the first aspect in the treatment of waste plastic oil.

[0022] A third aspect of the present invention provides a method for removing impurities from waste plastic oil, the method comprising:

[0023] In the presence of a reaction solvent, waste plastic oil is brought into contact with each component of the composition described in the first aspect to react, and then the resulting reaction product is subjected to electro-desalting treatment, and then the product obtained from the electro-desalting treatment is subjected to oil-water separation.

[0024] Through the above technical solution, the composition provided by this invention is used to treat waste plastic oil, achieving iron and calcium removal rates of over 58% and over 65%, respectively, and a chlorine removal rate of over 40%, reaching a maximum of 45.5%, demonstrating good demetallization and dechlorination effects. Furthermore, in a preferred embodiment, the reaction conditions are also more moderate. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] In this invention, unless otherwise stated, all pressures are gauge pressures.

[0027] As previously stated, a first aspect of the present invention provides a composition for treating waste plastic oil, wherein, based on the total amount of the composition, the composition contains the following components, which may be stored independently or in combination:

[0028] 30-45 wt% of a carboxylic acid polymer, 5-10 wt% of hydroxamic acid, 5-20 wt% of a polyether imidazoline compound, and 5-10 wt% of a demulsifier; wherein the polyether imidazoline compound is an alkylphenol resin polyether imidazoline having the general formula structure shown in Formula I:

[0029]

[0030] In the formula, R is nonyl or octyl; a is 2-10; x is 1-2; y is 5-8.

[0031] According to some embodiments of the present invention, preferably, the carboxylic acid polymer is at least one selected from acrylic acid polymer, hydrolyzed polymaleic anhydride, acrylic acid-maleic anhydride copolymer, acrylic acid-acrylate copolymer, and acrylic acid-2-acrylamide-2-methylpropylsulfonic acid (AMPS) copolymer, and more preferably an acrylic acid-acrylate copolymer. The acrylic acid-acrylate copolymer can be a binary copolymer or a ternary copolymer.

[0032] According to some embodiments of the present invention, preferably, the acrylic-acrylate copolymer is at least one selected from the following: acrylic-methyl acrylate copolymer, acrylic-hydroxyethyl acrylate copolymer, acrylic-hydroxypropyl acrylate copolymer, acrylic-hydroxyethyl methacrylate copolymer, acrylic-hydroxypropyl methacrylate copolymer, and acrylic-hydroxypropyl acrylate-methyl acrylate terpolymer, most preferably acrylic-hydroxypropyl acrylate copolymer. Using the acrylic-acrylate copolymer of the above-mentioned preferred embodiments, in combination with the components in the composition, is beneficial for obtaining better removal effects of impurities such as metals (e.g., calcium, iron) and chlorine.

[0033] According to some embodiments of the present invention, preferably, the weight-average molecular weight of the acrylic-acrylate copolymer is 1000-50000 g / mol, more preferably 2000-40000 g / mol.

[0034] According to some embodiments of the present invention, preferably, in the acrylic-acrylate copolymer, the molar ratio of acrylic structural units to acrylate structural units is 0.1-20:1, more preferably 0.5-10:1.

[0035] The acrylic-acrylate copolymer described in the preferred embodiment, in combination with the components in the composition, is beneficial for obtaining better removal of impurities such as metals (e.g., calcium, iron) and chlorine.

[0036] According to some embodiments of the present invention, the polyether imidazoline compound is an alkylphenol resin polyether imidazoline, which has the general formula structure shown in Formula I:

[0037]

[0038] In the formula, R is nonyl or octyl, preferably nonyl; a is 2-10, preferably 4-6; x is 1-2; y is 5-8;

[0039] Preferably, the polyether imidazoline compound is a nonylphenolic resin polyether imidazoline, i.e., R in Formula I is nonyl. Using the above preferred embodiment is beneficial for obtaining better removal effects of impurities such as metals (e.g., calcium, iron) and chlorine.

[0040] According to some embodiments of the present invention, the polyether imidazoline compound can be obtained commercially or prepared in-house.

[0041] According to some embodiments of the present invention, preferably, the polyether imidazoline compound is prepared by a method comprising the following steps:

[0042] (S1) The alkylphenol resin polyether is contacted with succinic anhydride to carry out a first reaction to obtain a carboxylated polyether; the first reaction is a carboxylation reaction.

[0043] (S2) The carboxylated polyether is contacted with diethylenetriamine to carry out a second reaction; the second reaction includes an amidation reaction and a cyclization reaction.

[0044] According to some embodiments of the present invention, preferably, in step (S1), the alkylphenol resin polyether has the general formula structure shown in Formula II:

[0045]

[0046] In the formula, R, a, x, and y are defined and selected as described above, and will not be repeated here.

[0047] Preferably, the alkylphenolic resin polyether is nonylphenolic resin polyether.

[0048] According to some embodiments of the present invention, the alkylphenol resin polyether can be obtained commercially or prepared in-house.

[0049] According to a preferred embodiment of the present invention, the alkylphenolic resin polyether is prepared by a method comprising the following steps:

[0050] 1) Under an inert atmosphere, alkylphenol resin and base I are reacted with propylene oxide to obtain an intermediate product; wherein:

[0051] The alkali I is sodium hydroxide and / or potassium hydroxide; the mass ratio of the alkylphenol resin, the alkali I, and the propylene oxide is 50-240:1:35-200.

[0052] The reaction conditions include: a temperature of 125-135℃, a pressure of 0.1-0.5MPa, and a time of 15min-2h;

[0053] 2) Under an inert atmosphere, the intermediate product and base II are reacted with ethylene oxide to obtain alkylphenol resin polyether; wherein:

[0054] The base II is sodium hydroxide and / or potassium hydroxide; the mass ratio of the intermediate product, the base II and the ethylene oxide is 100:1-2:10-30;

[0055] The reaction conditions include: a temperature of 115-125℃, a pressure of 0.1-0.5MPa, and a time of 15min-2h.

[0056] Preferably, in step 1), the alkylphenol resin can be commercially available or prepared in-house. Its preparation method may include:

[0057] In the presence of a catalyst, alkylphenols and formaldehyde undergo a condensation reaction. The catalyst can be an acid or a base, and the specific reaction conditions are well known to those skilled in the art and will not be described in detail here.

[0058] Preferably, in step 1), the degree of polymerization of the alkylphenol resin is 2-10, more preferably 4-6; the weight-average molecular weight is 440-2200 g / mol, more preferably 880-1320 g / mol.

[0059] According to some embodiments of the present invention, preferably, the weight-average molecular weight of the alkylphenol resin polyether is 440-2200 g / mol, more preferably 880-1320 g / mol; and the hydroxyl value is 25.5-127 mgKOH / g, more preferably 42.4-63.6 mgKOH / g.

[0060] According to some embodiments of the present invention, preferably, in step (S1), the mass ratio of the alkylphenol resin polyether to the succinic anhydride is 90-150:8, more preferably 100-120:8, and even more preferably 100-110:8.

[0061] According to some embodiments of the present invention, in step (S1), the first reaction is a carboxylation reaction. The equation for the first reaction is as follows:

[0062]

[0063] Preferably, the conditions for the first reaction include: a temperature of 100-120℃, more preferably 105-115℃; and a time of 1-8h, more preferably 2-6h.

[0064] According to some embodiments of the present invention, preferably, in step (S2), the mass ratio of the carboxylated polyether to the diethylenetriamine is 11-15:1, more preferably 12-14:1.

[0065] According to some embodiments of the present invention, in step (S2), the second reaction includes an amidation reaction and a cyclization reaction. The equation for the second reaction includes:

[0066]

[0067] Preferably, in step (S2), the contacting step includes: first mixing the carboxylated polyether with diethylenetriamine at a temperature of 140-160°C, preferably 145-155°C, and then heating to 230-250°C, preferably 235-245°C, until no water is generated.

[0068] According to some embodiments of the present invention, the inert atmosphere is provided by at least one inert gas selected from nitrogen, argon, neon and helium.

[0069] According to some embodiments of the present invention, preferably, the hydroxamic acid is salicylic acid.

[0070] According to some embodiments of the present invention, preferably, the demulsifier is at least one of fatty alcohol polyoxypropylene polyoxyethylene ether, polyol polyoxypropylene polyoxyethylene ether, polyethylene polyamine polyoxypropylene polyoxyethylene ether, alkylphenol polyoxypropylene polyoxyethylene ether, and alkylphenol amine polyoxypropylene polyoxyethylene ether.

[0071] According to some embodiments of the present invention, preferably, the composition further includes a solvent, said solvent being water and / or ethanol. Preferably, the solvent content is 35-65 wt%, more preferably 40-60 wt%, based on the total amount of the composition.

[0072] A second aspect of the present invention provides the use of the composition described in the first aspect in the treatment of waste plastic oil.

[0073] A third aspect of the present invention provides a method for removing impurities from waste plastic oil, the method comprising:

[0074] In the presence of a reaction solvent, waste plastic oil is brought into contact with each component of the composition described in the first aspect to react, and then the resulting reaction product is subjected to electro-desalting treatment, and then the product obtained from the electro-desalting treatment is subjected to oil-water separation.

[0075] According to some embodiments of the present invention, preferably, the mass ratio of the waste plastic oil to the composition is 100:0.1-0.5.

[0076] According to some embodiments of the present invention, preferably, the total content of iron and calcium in the waste plastic oil, calculated by element, is in a mass ratio of 1:5-10 to the amount of the composition used.

[0077] According to some embodiments of the present invention, preferably, the total content of iron and calcium in the waste plastic oil, calculated by element, is 1-800 μg / g.

[0078] According to some embodiments of the present invention, preferably, the waste plastic oil contains 50-5000 μg / g of organochlorine by elemental calculation.

[0079] According to some embodiments of the present invention, preferably, the reaction solvent is water.

[0080] According to some embodiments of the present invention, preferably, the mass ratio of the waste plastic oil to the reaction solvent is 100:10-50.

[0081] According to some embodiments of the present invention, preferably, the reaction conditions include: a reaction temperature of 80-110°C, more preferably 90-110°C; and a reaction time of 1-10 h, more preferably 1-3 h.

[0082] According to some embodiments of the present invention, preferably, the conditions for the electro-desalination treatment include: a temperature of 80-130°C, preferably 80-120°C; an electric field strength of 100-300V / cm, preferably 150-250V / cm; and a time of 0.5-3h, preferably 1-2h.

[0083] The present invention will be described in detail below through embodiments.

[0084] In the following examples and comparative examples, unless otherwise specified, all raw materials used are commercially available products. Among them:

[0085] The acrylic acid-hydroxypropyl acrylate copolymer was purchased from Linhua Water Stabilizer Factory; the molar ratio of acrylic acid structural units to acrylate structural units was 2:1, and its weight-average molecular weight was 3000 g / mol; it was provided in the form of a 50 wt% aqueous solution.

[0086] Salicylic acid was purchased from Inokai Reagents Co., Ltd.

[0087] The demulsifier RP-2 (polyol polyoxypropylene polyoxyethylene ether) was purchased from Beijing Linhua Water Stabilizer Factory;

[0088] The properties of waste plastic oil are shown in Table 1, and the composition of its chlorinated compounds is shown in Table 2. These chlorinated hydrocarbons are products obtained by the addition of HCl produced from the decomposition of polyvinyl chloride and olefins or alkynes produced from the decomposition of plastics such as polyethylene (PE) and polypropylene (PP).

[0089] Table 1

[0090] project Raw material oil A Raw material oil B <![CDATA[Density (20 °C) / (kg / m 3 )]]> 850.2 863.4 Oxygen mass fraction / % - 3.4 Mechanical impurities / wt% ＜0.005 ＜0.005 Fe / (μg / g) 164 9.3 Ca / (μg / g) 234 0.2 Na / (μg / g) 7.6 ＜0.1 <![CDATA[Total chlorine (calculated as Cl - ) / wt%]]> 0.38 0.24 Total acid value (mgKOH / g) 0.8 20.11

[0091] Table 2

[0092]

[0093]

[0094] The following preparation examples illustrate the polyether imidazoline compounds and their preparation methods provided by the present invention.

[0095] Nonylphenolic resin polyether is prepared by a method comprising the following steps:

[0096] 1) Preparation of nonylphenol resin

[0097]

[0098] 100g of nonylphenol (molecular weight 220) was added to a three-necked flask and immersed in a 75°C constant temperature water bath. A certain amount of concentrated hydrochloric acid (37wt%) was added to adjust the pH of the solution to 3-5. After stirring evenly, 38.9g of formaldehyde (35wt%) (molecular weight 30) was added dropwise at a rate of 1 drop / s over 1 hour. The polymerization temperature was kept below 80°C. The supernatant was removed from the product, and the product was washed with water to obtain nonylphenol resin (with a weight-average molecular weight of 970g / mol and a degree of polymerization of 4).

[0099] 2) Preparation of nonylphenolic resin polyether

[0100]

[0101] 110g of the obtained nonylphenol resin and 1.1g of potassium hydroxide were added to a high-pressure reactor, purged with nitrogen to remove air, vacuumed, stirred, and heated to 130℃. Then, 132g of propylene oxide (molar ratio 6) was added dropwise at 0.3MPa and 135℃. After the addition was complete, the reaction continued for 0.5h, and the product was cooled and discharged to obtain the intermediate product.

[0102] 100g of the obtained intermediate product and 1.86g of potassium hydroxide were added to a high-pressure reactor. The reactor was purged with nitrogen and evacuated. Stirring was started and the temperature was raised to 120℃. Then, 19g of ethylene oxide was added dropwise at a pressure of 0.3MPa and a temperature of 125℃. After the addition was complete, the reaction was continued for 0.5h. The product was cooled and discharged to obtain nonylphenolic resin polyether (with a weight-average molecular weight of 1244g / mol and a hydroxyl value of 45mgKOH / g).

[0103] Preparation Example 1

[0104] (S1) In a three-necked flask, 100g of alkylphenol resin polyether was reacted with succinic anhydride to carry out a first reaction, yielding carboxylated polyether; wherein:

[0105] The alkylphenolic resin polyether is the nonylphenolic resin polyether obtained above;

[0106] The mass ratio of alkylphenol resin polyether to succinic anhydride is 100:8;

[0107] The first reaction is a carboxylation reaction; the conditions for the first reaction are: temperature 110℃, time 6h; wherein, after the reaction proceeds for 1h, the acid value is measured every 0.5h until the acid value no longer changes;

[0108] (S2) In a three-necked flask, 108 g of the above carboxylated polyether was contacted with diethylenetriamine to carry out a second reaction, yielding nonylphenolic resin polyether imidazoline Z1; wherein:

[0109] The mass ratio of carboxylated polyether to diethylenetriamine is 108:8.3;

[0110] The second reaction includes amidation and cyclization reactions; the contact steps are as follows: first, diethylenetriamine is added dropwise to carboxylated polyether at 150°C for mixing, and the water produced is continuously condensed and separated until the acid value is balanced. Then, the temperature is raised to 240°C until no more water is generated, and the reaction is stopped.

[0111] Preparation Example 2

[0112] Following the method of Preparation Example 1, except that in step (S1), the mass ratio of alkylphenol resin polyether to succinic anhydride is 100:6, while all other steps are the same, nonylphenol resin polyether imidazoline Z2 is obtained.

[0113] The following examples illustrate the composition for treating waste plastic oil and the method for removing impurities from waste plastic oil provided by the present invention.

[0114] Example 1

[0115] In the presence of a reaction solvent, 100g of waste plastic oil was contacted with a composition for treating waste plastic oil and reacted under reflux conditions. The resulting reaction product was then subjected to electro-desalting treatment, followed by oil-water separation to obtain an aqueous phase and an oil phase.

[0116] Waste plastic oil is raw material oil A; the types and amounts of each component in the composition for treating waste plastic oil are shown in Table 3; the mass ratio of waste plastic oil to the composition is 100:0.3;

[0117] The reaction solvent is water; the mass ratio of waste plastic oil to the reaction solvent is 100:20.

[0118] The reaction conditions were: reaction temperature 105℃; reaction time 1 hour.

[0119] The conditions for electro-desalination were: temperature 90℃; electric field strength 200V / cm; time 1h.

[0120] The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0121] Example 2

[0122] The method of Example 1 was followed, except that the amounts of each component in the composition for treating waste plastic oil were as shown in Table 3; all other aspects were the same, resulting in an aqueous phase and an oil phase. The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0123] Example 3

[0124] The method of Example 1 was followed, except that the amounts of each component in the composition for treating waste plastic oil were as shown in Table 3; all other aspects were the same, resulting in an aqueous phase and an oil phase. The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0125] Example 4

[0126] The method is the same as in Example 1, except that:

[0127] The types and amounts of each component in the composition for treating waste plastic oil are detailed in Table 3.

[0128] The mass ratio of waste plastic oil to this composition is 100:0.2;

[0129] The mass ratio of waste plastic oil to reaction solvent is 100:10;

[0130] The reaction conditions were: reaction temperature 90℃; reaction time 1 hour.

[0131] The conditions for electro-desalination were: temperature 90℃; electric field strength 200V / cm; time 1h.

[0132] Everything else is the same, resulting in an aqueous phase and an oil phase;

[0133] The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0134] Example 5

[0135] The method of Example 1 is followed, except that the waste plastic oil is raw material oil B, and all other aspects are the same, to obtain an aqueous phase and an oil phase;

[0136] The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0137] Comparative Example 1 (without reflux treatment)

[0138] The method is the same as in Example 1, except that a conventional electro-desalination method is used to treat the waste plastic oil, as detailed below:

[0139] Take 100g of waste plastic oil, preheat it to 95℃, and then mix it with the waste plastic oil treatment composition and reaction solvent using a Waring mixer for 30s. The resulting oil-water mixture is then subjected to electro-desalting treatment, and the product obtained from the electro-desalting treatment is subjected to oil-water separation. Wherein:

[0140] The mass ratio of waste plastic oil to this composition is 100:0.3;

[0141] The reaction solvent is water; the mass ratio of waste plastic oil to the reaction solvent is 100:20.

[0142] The conditions for electro-desalination were: temperature 90℃; electric field strength 200V / cm; time 1h.

[0143] The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0144] Comparative Example 2

[0145] The method of Example 1 was followed, except that the composition for treating waste plastic oil did not contain salicylic acid and polyether imidazoline compounds. The types and amounts of each component are shown in Table 3. All other aspects were the same, and an aqueous phase and an oil phase were obtained. The obtained oil phase was analyzed for its metal and total chlorine content, and the results are shown in Table 4.

[0146] Table 3

[0147]

[0148] Table 4 (wherein, pre-desorption oil refers to waste plastic oil, and post-desorption oil refers to the obtained oil phase).

[0149]

[0150] The results above show that when waste plastic oil is treated with the composition provided by the present invention, the removal rates of iron and calcium are above 58% and 65%, respectively, and the removal rate of chlorine is above 40%, with a maximum of 45.5%, demonstrating good demetallization and dechlorination effects.

[0151] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composition for treating waste plastic oil, characterized in that, Based on the total amount of the composition, the composition contains the following components, which may be stored individually or in combination: 30-45 wt% carboxylic acid polymer, 5-10 wt% hydroxamic acid, 5-20 wt% polyether imidazoline compound and 5-10 wt% demulsifier; The carboxylic acid polymer is at least one of acrylic acid polymer, hydrolyzed polymaleic anhydride, acrylic acid-maleic anhydride copolymer, acrylic acid-acrylate copolymer, and acrylic acid-2-acrylamide-2-methylpropylsulfonic acid copolymer. The demulsifier is at least one of fatty alcohol polyoxypropylene polyoxyethylene ether, polyol polyoxypropylene polyoxyethylene ether, polyethylene polyamine polyoxypropylene polyoxyethylene ether, alkylphenol polyoxypropylene polyoxyethylene ether, and alkylphenol amine polyoxypropylene polyoxyethylene ether. The polyether imidazoline compound is an alkylphenol resin polyether imidazoline, which has the general formula structure shown in Formula I: Formula I; In the formula, R is nonyl or octyl; a is 2-10; x is 1-2; y is 5-8.

2. The composition according to claim 1, wherein, The carboxylic acid polymer is an acrylic acid-acrylate copolymer.

3. The composition according to claim 2, wherein, The acrylic-acrylate copolymer is at least one of the following: acrylic-methyl acrylate copolymer, acrylic-hydroxyethyl acrylate copolymer, acrylic-hydroxypropyl acrylate copolymer, acrylic-hydroxyethyl methacrylate copolymer, acrylic-hydroxypropyl methacrylate copolymer, and acrylic-hydroxypropyl acrylate-methyl acrylate terpolymer.

4. The composition according to claim 3, wherein, The weight-average molecular weight of the acrylic acid-acrylate copolymer is 1000-50000 g / mol.

5. The composition according to claim 4, wherein, The weight-average molecular weight of the acrylic acid-acrylate copolymer is 2000-40000 g / mol.

6. The composition according to claim 5, wherein, In the acrylic acid-acrylate copolymer, the molar ratio of acrylic acid structural units to acrylate structural units is 0.1-20:

1.

7. The composition according to claim 6, wherein, In the acrylic acid-acrylate copolymer, the molar ratio of acrylic acid structural units to acrylate structural units is 0.5-10:

1.

8. The composition according to claim 1, wherein, In Equation I, R is a nonylene; a is 4-6.

9. The composition according to claim 1, wherein, The polyether imidazoline compound is prepared by a method comprising the following steps: (S1) The alkylphenol resin polyether is contacted with succinic anhydride to carry out a first reaction to obtain a carboxylated polyether; the first reaction is a carboxylation reaction; (S2) The carboxylated polyether is contacted with diethylenetriamine to carry out a second reaction; the second reaction includes an amidation reaction and a cyclization reaction.

10. The composition according to claim 9, wherein, In step (S1), the mass ratio of the alkylphenol resin polyether to the succinic anhydride is 90-150:

8.

11. The composition according to claim 10, wherein, The mass ratio of the alkylphenol resin polyether to the succinic anhydride is 100-120:

8.

12. The composition according to claim 11, wherein, The mass ratio of the alkylphenol resin polyether to the succinic anhydride is 100-110:

8.

13. The composition according to claim 11, wherein, In step (S1), the conditions for the first reaction include: a temperature of 100-120°C and a time of 1-8 hours.

14. The composition according to claim 13, wherein, The conditions for the first reaction include: a temperature of 105-115℃ and a time of 2-6 hours.

15. The composition according to any one of claims 9-14, wherein, In step (S2), the mass ratio of the carboxylated polyether to the diethylenetriamine is 11-15:

1.

16. The composition according to claim 15, wherein, The mass ratio of the carboxylated polyether to the diethylenetriamine is 12-14:

1.

17. The composition according to any one of claims 9-14, wherein, In step (S2), the contacting step includes: first mixing the carboxylated polyether with diethylenetriamine at a temperature of 140-160°C, and then heating to 230-250°C.

18. The composition according to claim 17, wherein, In step (S2), the contacting step includes: first mixing the carboxylated polyether with diethylenetriamine at a temperature of 145-155°C, and then heating to 235-245°C.

19. The composition according to any one of claims 1-14, wherein, The hydroxamic acid is salicylic acid.

20. The composition according to any one of claims 1-14, wherein, The composition further includes a solvent, which is water and / or ethanol; the solvent content is 35-65 wt% based on the total amount of the composition.

21. The composition according to claim 20, wherein, The solvent content is 40-60 wt% based on the total amount of the composition.

22. The use of the composition according to any one of claims 1-21 in the treatment of waste plastic oil.

23. A method for removing impurities from waste plastic oil, the method comprising: In the presence of a reaction solvent, waste plastic oil is brought into contact with each component of the composition according to any one of claims 1-21 to react, and then the resulting reaction product is subjected to electro-desalting treatment, and then the product obtained from the electro-desalting treatment is subjected to oil-water separation.

24. The method according to claim 23, wherein, The mass ratio of the waste plastic oil to the composition is 100:0.1-0.

5.

25. The method according to claim 23, wherein, In the waste plastic oil, the total content of iron and calcium, calculated by element, is in a mass ratio of 1:5-10 to the amount of the composition used.

26. The method according to claim 23, wherein, The waste plastic oil contains, by elemental calculation, a total content of iron and calcium of 1-800 µg / g.

27. The method according to claim 23, wherein, The waste plastic oil contains 50-5000 µg / g of organochlorine compounds, calculated as elements.

28. The method according to any one of claims 23-27, wherein, The reaction solvent is water.

29. The method according to any one of claims 23-27, wherein, The mass ratio of the waste plastic oil to the reaction solvent is 100:10-50.

30. The method according to any one of claims 23-27, wherein, The reaction conditions include: a reaction temperature of 80-110℃ and a reaction time of 1-10h.

31. The method according to claim 30, wherein, The reaction conditions include: a reaction temperature of 90-110℃ and a reaction time of 1-3h.

32. The method according to any one of claims 23-27, wherein, The conditions for the electro-desalination treatment include: a temperature of 80-130℃, an electric field strength of 100-300V / cm, and a time of 0.5-3h.

33. The method according to claim 32, wherein, The conditions for the electro-desalination treatment include: a temperature of 80-120℃, an electric field strength of 150-250V / cm, and a time of 1-2h.

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