Ionic liquid catalyst for producing renewable fuel from waste oil as well as preparation method and application of ionic liquid catalyst

Abstract

The invention discloses an ionic liquid catalyst for producing renewable fuel from waste grease as well as a preparation method and application of the ionic liquid catalyst, and belongs to the technical field of waste grease treatment. The self-synthesized ionic liquid catalyst is adopted to catalyze hydrogenation of the waste oil and fat to produce renewable fuel, impurities in the waste oil and fat can be adsorbed or converted into products, the yield and quality of the products are improved, and a foundation is laid for industrial production of second-generation biodiesel from the waste oil and fat.

Description

Technical Field

[0001] The present application relates to an ionic liquid catalyst for producing renewable fuel from waste oil and fat, and a preparation method and application thereof, belonging to the technical field of waste oil and fat treatment. Background Art

[0002] With the implementation of environmental protection and carbon emission reduction actions, the proportion of green fuels such as biodiesel and bio-jet fuel produced by bio-based oil processing is increasing year by year, resulting in the increasing shortage of raw material sources. Expanding the source of raw materials for green fuels has become an urgent issue. In the catering, food processing, oil production and processing, meat processing, fur processing and other industries, a considerable amount of waste oils including acidified oil, kitchen waste oil, sewage oil, deteriorated oil, animal fat, etc. are generated every year. These oils have low usable value and a long degradation process. They are environmental pollutants that cause eutrophication of water bodies and foul air.

[0003] If it is used as a raw material for green fuel, it will produce good social benefits and considerable economic gains. Currently, researchers are committed to using the above-mentioned waste oil to prepare renewable fuels such as diesel.

[0004] However, because waste bio-based oils contain many impurities and are seriously deteriorated, they contain not only natural components such as phospholipids, proteins, glycosyl diglycerides, heavy metal ions and unsaturated components, but also oxidative deterioration components such as alcohols, ketones, aldehydes, acids, as well as impurities such as dust, salt, and water. Most of these substances exist in the oil in the form of colloids that are difficult to separate and remove, causing the waste oil to produce corresponding thermal polymerization. Therefore, in the heating process at the beginning of production, thermal polymerization will occur and adhere to or accumulate on the heating equipment, causing the heat transfer components to overheat due to the obstruction of heat conduction, further aggravating the occurrence of thermal polymerization and forming a vicious circle. If the thermal polymer is not cleaned up in time, it will quickly develop into a blockage of the material passage of the heat exchange component and coking of the heat exchange surface, making it difficult to continue production continuously.

[0005] In order to solve this problem, the latest method in the industry is to extract a portion of the intermediate hot oil that is not heat-polymerizable after being upgraded by the reactor, and then further heat it to the required temperature value in a heating furnace, and then add it to the feed end and mix it with the cold initial feed in proportion, so as to "heat" the cold feed oil and dilute the impurities it contains. Since the process operation is manifested as the circulation of hot oil, this process method realizes the heating of the feed oil without equipment, which not only fundamentally avoids the problem of easy coking and carbonization of the heating equipment, but also improves the quality of the feed oil to a certain extent, which is conducive to reducing the pressure of subsequent processes.

[0006] For example, Patent 202211376662.X and Patent 202310606126.2 both use this method and cooperate with specific catalysts for hydrogenation pretreatment operations. However, the catalysts they use are all carbon-based catalysts, which are a type of solid catalyst. Solid catalysts are easily affected by impurities in the raw materials and become clogged, resulting in a short overall process operation cycle. Therefore, the use of carbon-based catalysts in the above two patents is mainly to utilize its impurity resistance function, but this type of catalyst has high requirements for equipment and is generally used in crude oil refining. If you want to use it for industrial applications to treat waste oil, you also need to specially treat the raw oil before mixing.

[0007] In view of the above shortcomings, researchers began to develop liquid catalysts and ionic liquid catalysts to replace traditional carbon-based catalysts. For example, patent HK1212547A discloses an ionic liquid catalyst for catalyzing oil to prepare biodiesel, but the ionic liquid catalyst catalyzes the transesterification reaction, and the obtained biodiesel belongs to the first-generation biodiesel, while the structure and performance of the second-generation biodiesel are closer to petrochemical diesel; in order to produce the second-generation biodiesel, patent 202210251260.0 discloses an oil-soluble molybdenum-based ionic liquid catalyst, which can catalyze waste oil to produce the second-generation biodiesel, and can make the yield of the second-generation biodiesel in the liquid phase product more than 85%. In order to improve the catalytic efficiency of the catalyst and reduce production costs, patent 202311642817.4 is committed to using bimetallic ionic liquid catalysis to make the yield of alkanes reach more than 90%. However, the yields and other parameters obtained in the above literature are all based on laboratory research. Since waste oil contains many impurities and is severely deteriorated, it is easy to coke and difficult to produce when it is used for industrial catalytic hydrogenation to prepare diesel, alkanes and other products. When using such ionic liquid catalysts for industrial catalytic hydrogenation production, it is still necessary to pre-treat the waste oil with a treatment agent or filter to remove solid impurities. For example, in patent 202311773339.0, it is necessary to use a pre-treatment agent to perform ester exchange reaction and impurity removal reaction on the waste oil to reduce the acid value and impurities of the waste oil before it can be used to produce renewable fuels such as diesel. Summary of the invention

[0008] In order to solve the above problems, an ionic liquid catalyst for producing renewable fuel from waste oil is provided. The liquid catalyst introduces functional segments into the ionic liquid catalyst through self-prepared functional halogenated alkane monomers, thereby ensuring the lipophilicity of the ionic liquid catalyst while achieving the removal of metal ions, impurities and phospholipids in the waste oil, thereby making it possible to industrially prepare second-generation biodiesel from waste oil and further improve the yield of second-generation biodiesel.

[0009] The method for producing renewable fuel by treating waste oil with ionic liquid catalyst adopts circulating oil to heat the raw waste oil, and increases the amount of circulating oil added, which can significantly reduce the impurity concentration in the raw oil, is more conducive to the catalysis of the liquid catalyst, and omits the step of reheating after mixing the liquid catalyst, omits the heat exchanger, and does not require repeated mixing of the raw materials. The operation process is simple, which is conducive to industrial promotion and use, and can also synergistically improve the yield and quality of the product.

[0010] According to one aspect of the present application, a method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat is provided, comprising the following steps:

[0011] (1) Preparation of functional halogenated alkane monomers: a halogenated alkane containing a carboxyl group and a functional monomer containing a hydroxyl group are reacted and treated to obtain a functional halogenated alkane monomer, wherein the functional monomer containing a hydroxyl group is at least one selected from the group consisting of N-cyclohexylhydroxylamine, N-(benzylcarbonyloxy)hydroxylamine, N-hydroxymethylnicotinamide, 5-hydroxytryptamine, and N-benzylethanolamine;

[0012] (2) Preparation of intermediate B: reacting a monomer containing a tertiary amine with a functional halogenated alkane monomer, treating the monomer to obtain intermediate A, and treating intermediate A with a strong alkaline anion exchange resin to obtain intermediate B;

[0013] (3) Preparation of ionic liquid catalyst: The intermediate B and the polymetallic acid salt are mixed and heated to react, and then dried to obtain the ionic liquid catalyst.

[0014] The ionic liquid catalyst prepared in the present application adopts a synthetic functional halogenated alkane monomer so that the catalyst contains a long-chain alkyl group with a functional group. The introduction of the long-chain alkyl group with a functional group can ensure the lipophilicity of the ionic liquid catalyst, promote the uniform dispersion of the ionic liquid catalyst in the raw material, and realize the adsorption of metal ions, impurities and phospholipids during the catalytic hydrogenation of the ionic liquid catalyst, thereby reducing the content of harmful substances in the raw oil, reducing coking, and facilitating industrial continuous production.

[0015] Optionally, the halogenated alkane containing a carboxyl group has 6 to 11 carbon atoms;

[0016] Preferably, the carboxyl-containing halogenated alkane is selected from at least one of 6-chlorohexanoic acid, 7-chloroheptanoic acid, 8-chlorooctanoic acid, 9-chlorononanoic acid, 10-chlorodecanoic acid, 11-chloro-undecanoic acid, 6-bromohexanoic acid, 7-bromoheptanoic acid, 8-bromooctanoic acid, 9-bromononanoic acid, 10-bromodecaneic acid, and 11-bromo-undecanoic acid.

[0017] The above-mentioned halogenated alkane containing carboxyl groups contains at least 6 carbon atoms, and reacts with a functional monomer containing hydroxyl groups to prepare a long-chain halogenated alkane monomer with functional groups, so that the functional halogenated alkane monomer retains the original long-chain alkane and can introduce functional groups such as amino, cycloalkyl, carbonyl, ester, benzene ring, etc., thereby achieving the removal of metal ions, impurities and phospholipids.

[0018] In addition, the ionic liquid catalyst for the synthesis of functional halogenated alkanes prepared in the present application can also realize the hydrogenation conversion of alcohols, aldehydes, ketones, acids and other substances in waste oils and fats into alkanes, thereby reducing the impurity content of the product and improving the yield of second-generation biodiesel.

[0019] Optionally, in step (3), the molar ratio of intermediate B to polymetallic acid salt is (3-4):1, the reaction temperature is 60-70°C, the reaction time is 60-72h, nitrogen is continuously introduced during the reaction, and the tail gas is introduced into dilute sulfuric acid, the molar ratio of dilute sulfuric acid to polymetallic acid salt is 1:0.06, and the concentration of ammonium sulfate in dilute sulfuric acid is detected. When the concentration is ≤1mmol / L, the reaction is terminated, followed by rotary evaporation drying at 80-90°C, and finally vacuum drying at 80°C for at least 72h.

[0020] Optionally, the functional monomer containing a hydroxyl group is selected from N-(benzylcarbonyloxy)hydroxylamine.

[0021] The N-cyclohexylhydroxylamine functional monomer contains an amino group and a cycloalkyl group, wherein the amino group can improve the removal rate of ions, impurities and phospholipids, and the cycloalkyl group can increase the lipophilicity of the ionic liquid catalyst, thereby achieving uniform dispersion of the ionic liquid catalyst.

[0022] N-(Benzylcarbonyloxy)hydroxylamine contains an amino group, an ester group and a benzene ring, wherein the amino group and the benzene ring can achieve the removal of metal ions, impurities and phospholipids, the ester group can increase the compatibility with waste oils and fats, and achieve uniform dispersion of the ionic liquid catalyst. In addition, the benzene ring structure can also improve the temperature resistance of the ionic liquid catalyst, so that the ionic liquid catalyst still maintains a high catalytic effect at high temperatures.

[0023] N-hydroxymethylnicotinamide contains an amino group, a carbonyl group and a benzene ring. The carbonyl group is used to increase lipophilicity, but compared with the ester group, its compatibility with waste oils and fats decreases. Therefore, the catalytic effect of N-hydroxymethylnicotinamide is lower than that of N-(benzylcarbonyloxy)hydroxylamine.

[0024] 5-hydroxytryptamine has two amino groups that can increase the adsorption of metal ions, impurities and phospholipids, but its lipophilicity is lower than that of N-(benzylcarbonyloxy)hydroxylamine. In addition, since the hydroxyl group is set on the benzene ring, the reaction yield with halogenated alkanes containing carboxyl groups is reduced, and the production cost increases.

[0025] The benzene ring contained in N-benzylethanolamine can improve the temperature resistance of the ionic liquid catalyst. However, the tertiary amine group contained in it has a lower adsorption effect on metal ions, impurities and phospholipids than the amino group of N-(benzylcarbonyloxy)hydroxylamine, and long-term operation will still cause the system to have the risk of coking.

[0026] Optionally, the monomer containing a tertiary amine is selected from at least one of trihexylamine, triheptylamine, trioctylamine, pyridine, N-methylimidazole, N-methylpyrrole, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethylhexanediamine, and 4,4'-bipyridine.

[0027] Preferably, the monomer containing tertiary amine is selected from at least one of N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethylhexanediamine and 4,4'-bipyridine.

[0028] The tertiary amine monomer contains two tertiary amine groups. When the intermediate A is prepared by reacting the tertiary amine monomer with a functional halogenated alkane monomer, the intermediate A contains a diquaternary ammonium salt structure. Compared with ionic liquid catalysts prepared from other monomers, the intermediate A has higher dispersibility and catalytic efficiency in waste oils and fats, and has a bisymmetrical structure, which can make the catalytic efficiency of the catalytic active center after combining with the polymetallic acid salt the same, thereby improving the catalytic uniformity of the waste oils and fats, so as to obtain a second-generation biodiesel with higher yield and more stable performance.

[0029] Optionally, the polymetallic acid salt is a trimetallic acid salt comprising at least molybdenum and nickel metals;

[0030] Preferably, the trimetallic acid salt is selected from at least one of molybdenum nickel cobaltate, molybdenum nickel manganate, and molybdenum nickel zincate;

[0031] More preferably, the preparation method of the trimetallic acid salt is:

[0032] Hydrogen peroxide, nickel sulfate and a third metal sulfate are added to deionized water, and then slowly added dropwise to a boiling ammonium molybdate solution. During the dropping process, the ammonium molybdate solution is kept boiling. After the dropping is completed, the solution is boiled for 1-2 hours to obtain a trimetallic acid salt. The third metal sulfate is selected from one of cobalt sulfate, manganese sulfate or zinc sulfate.

[0033] Although the catalytic activity of molybdenum is lower than that of nickel, the content of molybdenum involved in the catalysis is high. The catalytic activity of nickel is high, but there will be more nickel that cannot effectively participate in the catalytic process. Therefore, molybdenum and nickel in the above-mentioned trimetallic acid salt are used as basic catalytic metals, which can cooperate with the catalytic properties of the two metals, so that the catalytic efficiency can be further improved when combined with the third metal. At the same time, it is not easily affected by metal elements, impurities and phospholipids in waste oils and fats, thereby improving the service life of the catalyst. In addition, the trimetallic acid salt has a good reaction combination effect with the intermediate B prepared above, and a better catalytic hydrogenation effect is obtained on the waste oil raw materials.

[0034] Optionally, the molar ratio of the nickel sulfate to ammonium molybdate is (0.5-0.8):1, the molar ratio of the cobalt sulfate, manganese sulfate or zinc sulfate to ammonium molybdate is (0.3-0.4):1, the hydrogen peroxide accounts for 8-10wt% of the weight of ammonium molybdate, and the concentration of hydrogen peroxide in the hydrogen peroxide is 30wt%.

[0035] Based on the above-mentioned catalytic properties of molybdenum and nickel, the molar ratio of the trimetallic salt nickel sulfate to ammonium molybdate, the molar ratio of cobalt sulfate, manganese sulfate or zinc sulfate to ammonium molybdate, that is, the ratio of nickel, molybdenum and the third metal (cobalt, manganese, zinc) in the ionic liquid catalyst, can improve the catalytic activity of the ionic liquid catalyst under the above-mentioned ratio, so that it can still maintain a high activity at high temperature of catalytic hydrogenation. If the proportion of ammonium molybdate is reduced, the overall catalytic activity of the liquid catalyst decreases; if the molar ratio of nickel sulfate is reduced, the service life of the ionic liquid catalyst decreases, resulting in a significant decrease in the late catalytic efficiency of catalytic hydrogenation, thereby reducing the product yield; if the proportion of the third metal is reduced, the overall catalytic activity and the service life of the catalyst will also be reduced, thereby reducing the yield of the product.

[0036] Optionally, in step (1), the specific method of reacting and treating the halogenated alkane containing a carboxyl group and the functional monomer containing a hydroxyl group to obtain the functional halogenated alkane monomer is:

[0037] A carboxyl-containing halogenated alkane and a hydroxyl-containing functional monomer in a molar ratio of 1:(1.1-1.2) are dissolved in a solvent, concentrated sulfuric acid is added as a catalyst, and then reacted at 60-70°C for at least 5 hours to obtain a crude product, the solvent is removed by vacuum distillation, and the product is extracted with ethyl acetate for 3-5 times and dried to obtain the product.

[0038] Optionally, in step (2), the specific method of reacting the monomer containing the tertiary amine with the functional halogenated alkane monomer and treating to obtain the intermediate A is:

[0039] The monomer containing the tertiary amine and the functional halogenated alkane monomer are dissolved in a solvent, heated under reflux for reaction for 22-24 hours, the solvent is removed by rotary evaporation, and the mixture is extracted with a mixed solvent of ether and acetonitrile for 3-5 times, and then dried to obtain the intermediate A.

[0040] Optionally, in step (2), the specific method of treating intermediate A with a strong basic anion exchange resin to obtain intermediate B is:

[0041] Dissolve intermediate A in an organic solvent and then add it to a - The product is placed in an ion exchange column of a strongly basic anion exchange resin, eluted with ethanol, and the strongly basic eluate with a pH value greater than 8 is collected and dried to obtain intermediate B.

[0042] According to another aspect of the present application, an ionic liquid catalyst prepared by the method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat as described in any one of the above items is provided.

[0043] According to another aspect of the present application, a method for producing renewable fuel by treating waste oil with an ionic liquid catalyst is provided, comprising the following steps:

[0044] S1: Mix circulating oil, waste grease and ionic liquid catalyst in a weight ratio of (1-6): 1:

[0045] (0.002-0.005) is mixed to form a premix, and then the temperature is raised to 280-380°C and then enters the first reactor for hydrogenation catalysis, wherein the ionic liquid catalyst is an ionic liquid catalyst prepared by the preparation method according to claim 1;

[0046] S2: The gas phase effluent of the first reactor enters the second reactor for further hydrogenation catalysis to obtain reactants and circulating oil, and the bottom effluent of the first reactor enters the ash discharge hot high-pressure separator to discharge waste containing high-ash oil and tailings;

[0047] S3: The reactants flow out to the hot high-pressure separator to separate into gas phase A and liquid phase A. The gas phase A enters the cold high-pressure separator to separate circulating hydrogen, combined distillate oil and residual oil. A part of the liquid phase A is used as circulating oil, and the other part enters the hot low-pressure separator to separate waste containing high-ash oil and tailings and liquid phase B;

[0048] S4: Liquid phase B enters a fractionation tower for fractionation to obtain renewable fuel.

[0049] Although some production processes also use recycled oil to return and mix with raw oil for catalytic hydrogenation, the amount of recycled oil used is relatively small. When waste oil is produced industrially, there is still a coking problem due to the excessive impurity content in the waste oil. After running for a certain period of time, the system often needs to be shut down for cleaning, which increases manpower and material resources and reduces production efficiency. In the preparation method of the present application, recycled oil with a high circulation ratio and waste oil are mixed and then catalytically hydrogenated. On the basis of saving heat energy, the colloid in the raw material is diluted, so that the production system is not easy to coke, and the production continuity is guaranteed. In the long run, it will still increase the industrial production capacity and have the best comprehensive benefits. It can also dilute or adsorb the sulfide and chloride in the raw material, thereby reducing the sulfur content and chlorine content in the product.

[0050] The first reactor used in the above method is a suspended bed reactor, which reduces the impurity content during the catalytic hydrogenation of the ionic liquid catalyst, thereby ensuring the smooth reaction of the second reactor. In addition, the amount of circulating oil used in this application is large, and the affinity with the long-chain alkyl of the functional group in the ionic liquid catalyst is better, so the circulating oil can promote the above-mentioned ionic liquid catalyst to be evenly dispersed in the waste oil and fat raw oil, promote the ionic liquid catalyst to better play the catalytic role, improve the catalytic efficiency, and then improve the product yield; and because it can be evenly dispersed and has better affinity with the circulating oil and waste oil, the long-chain alkyl of the functional group in the ionic liquid catalyst in the above process can play a better effect of removing impurities, metal ions and phospholipids, thereby reducing the content of impurities in the product.

[0051] Optionally, the temperature of the premix after heating is 300-360°C.

[0052] Optionally, the circulating oil has a density of 0.76-0.82 ml / g, and is a biomass hydrocarbon compound with a cetane index of more than 80.

[0053] Optionally, the renewable fuel includes biodiesel and / or biojet fuel;

[0054] Preferably, the renewable fuel includes hydrocarbon-based biodiesel, naphtha and kerosene.

[0055] Optionally, the waste grease includes at least one of acidified oil, waste kitchen grease, sewage oil and animal fat, and the acid value of the waste grease is greater than 40 mgKOH / g.

[0056] According to another aspect of the present application, there is provided an application of the method for producing renewable fuel by treating waste oil with an ionic liquid catalyst as described above in the preparation of bioenergy, biodiesel and biojet fuel.

[0057] The beneficial effects of this application include but are not limited to:

[0058] 1. According to the method of producing renewable fuel by treating waste oil with ionic liquid catalyst of the present application, the waste oil is treated by using circulating oil with high circulation ratio and liquid catalyst, and the high-efficiency catalysis and impurity removal of ionic liquid catalyst are combined, which fundamentally avoids the problem of coking and clogging of equipment (heating furnace tube) caused by raw materials, improves the continuity of production system operation, reduces the heat energy consumption of the system, reduces costs, saves investment, and facilitates industrial production and processing.

[0059] 2. According to the method of producing renewable fuel by treating waste oil with ionic liquid catalyst of the present application, the content of metal ions and other impurities in waste oil can be reduced through the improvement of ionic liquid catalyst, and the oxidative deteriorated components can be turned into treasure and directly converted into the final required product, which solves the technical problem of low product yield and low quality caused by many types and high content of impurities in waste oil, and has great economic benefits.

[0060] 3. According to the method of producing renewable fuel by treating waste oil with ionic liquid catalyst of the present application, no additional processing steps are added to the original hydrogenation treatment of waste oil. Therefore, the operation process of the method is simple, and the generation amount of renewable fuel is increased, the production efficiency is high, and it is easy to promote industrial production.

[0061] 4. According to the ionic liquid catalyst for producing renewable fuel from waste oil and fat of the present application, by improving the long-chain alkyl group carried by the existing ionic liquid catalyst, it is possible to remove metal ions, impurities and phospholipids in the waste oil and fat while ensuring the lipophilicity of the ionic liquid catalyst. The ionic liquid catalyst can directly catalyze the treatment of waste oil and fat to prepare second-generation biodiesel without pretreatment of the waste oil and fat, reduce coking, and can be used for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0063] Figure 1 This is a schematic diagram of a system for producing renewable fuel by treating waste oil through hot oil circulation according to Example 1 of the present application.

[0064] List of parts and reference numerals:

[0065] 1. Crude oil storage tank; 2. Booster pump; 3. Circulating oil heating furnace; 4. First reactor; 5. Second reactor; 6. Circulating oil pump; 7. Hot high-pressure separator; 8. Hot low-pressure separator; 9. Fractionation oil heating furnace; 10. Distillation tower; 11. One-side line oil; 12. Two-side line oil; 13. Three-side line oil; 14. Ash discharge hot high-pressure separator; 15. Ash settling tank; 16. Cold high-pressure separator; 17. Circulating hydrogen compressor; 18. Fresh hydrogen compressor; 19. Catalyst tank. DETAILED DESCRIPTION

[0066] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0067] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0068] Unless otherwise specified, the methods used in the embodiments of the present application are conventional methods in the prior art.

[0069] Example 1

[0070] refer to Figure 1 The present embodiment discloses a system for producing renewable fuel by treating waste oil through hot oil circulation, which includes a raw oil storage tank 1, a booster pump 2, a circulating oil heating furnace 3, a first reactor 4, a second reactor 5, a circulating oil pump 6, a hot high-pressure separator 7, a hot low-pressure separator 8, a fractionation oil heating furnace 9, a fractionation tower 10, a side line oil 11, a second side line oil 12, a third side line oil 13, an ash discharge hot high-pressure separator 14, an ash settling tank 15, a cold high-pressure separator 16, a circulating hydrogen compressor 17, a fresh hydrogen compressor 18, and a catalyst tank 19.

[0071] The basic process of producing renewable fuel using this system is:

[0072] S1: The waste oil after mechanical impurities and clear water are removed is placed in the raw oil storage tank 1 for storage, and dimethyl sulfide accounting for 2wt% of the waste oil is added to the raw oil storage tank 1 to make it evenly mixed with the waste oil. After that, the waste oil is pressurized by the booster pump 2, and then mixed with hydrogen to form a hydrogen-mixed oil. The hydrogen-mixed oil is then mixed with the circulating oil from the circulating heating furnace 3 and the ionic liquid catalyst from the catalyst tank 19, and then heated and homogenized to form a feed oil with a temperature of 280-380°C. The feed oil enters the first reactor 4 for catalytic hydrogenation, during which degumming, demetallization and other reactions and the removal of ash impurities in the product are also completed;

[0073] S2: The bottom material of the first reactor 4 is discharged through the ash discharge hot high-pressure separator 14 to discharge waste containing high-ash oil and tailings. The gaseous effluent of the first reactor 4 enters the second reactor 5 for hydrofining treatment to obtain reactants and circulating oil. The circulating oil is returned to the circulating heating furnace 3 through the circulating oil pump 6 for further temperature increase to be used for the mixed hydrogen oil to be evenly heated and homogenized.

[0074] S3: The reactant flows out to the hot high-pressure separator 7 to separate into gas phase A and liquid phase A. The gas phase A enters the cold high-pressure separator 16 to separate and remove water and water-soluble salts to obtain circulating hydrogen, combined distillate oil and residual oil. The circulating hydrogen is combined with the fresh hydrogen added by the fresh hydrogen compressor 18, and then the pressure is increased by the circulating hydrogen compressor 17, introduced into the feed end and mixed with the raw material oil for recycling. The combined distillate oil passes through the fractionation oil heating furnace 9 and enters the fractionation tower 10, and the residual oil is discharged for treatment;

[0075] Part of the liquid phase A is used as circulating oil and enters the circulating oil heating furnace 3 through the circulating oil pump 6, and the other part enters the hot low-pressure separator 8 to separate the liquid phase B and waste containing high-ash oil and tailings;

[0076] S4: Liquid phase B enters into the fractionation tower 10 for fractionation, and obtains one-side line oil 11 (naphtha), two-side line oil 12 (kerosene) and three-side line oil 13 (hydrocarbon-based biodiesel), which become various product oils that can be blended with green diesel and jet fuel. The residue at the bottom of the fractionation tower 10 is mainly heavy oil components that have not reacted completely, which are returned to the feed end and mixed with the raw oil for further processing;

[0077] The waste containing high-ash oil and tailings discharged from the bottom of the first reactor 4 and the hot low-pressure separator 8 enters the ash settling tank 15 for separation, and the residual oil is discharged for treatment. The rest is returned to the initial end of the process and mixed with the raw oil for further hydrogenation treatment.

[0078] Specifically, the temperature of the first reactor is 280-380°C, the pressure is 4-10MPa, and the hydrogen-oil ratio is 600-1000; the temperature of the second reactor is 260-320°C, the pressure is 4-8MPa, the volume space velocity is 0.5-3.0h-1, and the hydrogen-oil ratio is 400-800.

[0079] Example 2

[0080] This embodiment relates to the preparation of an ionic liquid catalyst, and the specific steps are as follows:

[0081] (1) Preparation of functional halogenated alkane monomers: a halogenated alkane containing a carboxyl group and a functional monomer containing a hydroxyl group are reacted and treated to obtain a functional halogenated alkane monomer, wherein the functional monomer containing a hydroxyl group is at least one selected from the group consisting of N-cyclohexylhydroxylamine, N-(benzylcarbonyloxy)hydroxylamine, N-hydroxymethylnicotinamide, 5-hydroxytryptamine, and N-benzylethanolamine;

[0082] (2) Preparation of intermediate B: reacting a monomer containing a tertiary amine with a functional halogenated alkane monomer, treating the monomer to obtain intermediate A, and treating intermediate A with a strong alkaline anion exchange resin to obtain intermediate B;

[0083] (3) Preparation of ionic liquid catalyst: The intermediate B and the polymetallic acid salt are mixed and heated to obtain the ionic liquid catalyst.

[0084] The halogenated alkane containing a carboxyl group is selected from at least one of 6-chlorohexanoic acid, 7-chloroheptanoic acid, 8-chlorooctanoic acid, 9-chlorononanoic acid, 10-chlorodecanoic acid, 11-chloro-undecanoic acid, 6-bromohexanoic acid, 7-bromoheptanoic acid, 8-bromooctanoic acid, 9-bromononanoic acid, 10-bromodecaneic acid, and 11-bromo-undecanoic acid.

[0085] The monomer containing tertiary amine is selected from at least one of trihexylamine, triheptylamine, trioctylamine, pyridine, N-methylimidazole, N-methylpyrrole, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethylhexanediamine and 4,4'-bipyridine.

[0086] The polymetallate is a trimetallate containing at least molybdenum and nickel metals;

[0087] Preferably, the trimetalate is selected from at least one of molybdenum nickel cobaltate, molybdenum nickel manganate, and molybdenum nickel zincate, and the preparation method of the trimetalate is:

[0088] Hydrogen peroxide, nickel sulfate and a third metal sulfate are added to deionized water, and then slowly added dropwise to a boiling ammonium molybdate solution. During the dropping process, the ammonium molybdate solution is kept boiling. After the dropping is completed, the solution is continued to be boiled to obtain a trimetallic acid salt. The third metal sulfate is selected from one of cobalt sulfate, manganese sulfate or zinc sulfate.

[0089] According to the above preparation method, ionic liquid catalysts 1#-13# and comparative ionic liquid catalysts D1#-D2# were prepared. The specific preparation method is as follows:

[0090] Ionic liquid catalyst 1#

[0091] (1) Preparation of functional halogenated alkane monomer: 0.1 mol of 6-chlorohexanoic acid and 0.11 mol of N-cyclohexylhydroxylamine were dissolved in a mixed solvent of ethanol and N,N-dimethylformamide (the volume ratio of ethanol to N,N-dimethylformamide was 1:1), and concentrated sulfuric acid accounting for 2 wt% of 6-chlorohexanoic acid was added as a catalyst, and then reacted at 60° C. for 8 h to obtain a crude product, and the solvent was removed by vacuum distillation, and the product was extracted with ethyl acetate for 3 times and dried to obtain the product;

[0092] (2) Preparation of intermediate B: 0.08 mol of trihexylamine and 0.08 mol of functional halogenated alkane monomer were dissolved in a mixed solvent of ethanol and acetone (the volume ratio of ethanol to acetone was 1:1), heated under reflux for 24 h, and the solvent was removed by rotary evaporation. The mixture was extracted three times with a mixed solvent of ether and acetonitrile in a volume ratio of 1:1, and then dried to obtain intermediate A. Intermediate A was dissolved in ethanol and added to a flask filled with OH - In an ion exchange column of a strong alkaline anion exchange resin, ethanol is used for elution, and the strong alkaline eluate with a pH value greater than 8 is collected and dried at 80°C for 24 hours to obtain intermediate B;

[0093] (3) Preparation of ionic liquid catalyst: Hydrogen peroxide (hydrogen peroxide concentration is 30 wt%) accounting for 8 wt% of the weight of ammonium molybdate, 0.05 mol of nickel sulfate and 0.04 mol of zinc sulfate are added to deionized water, and then slowly added dropwise to a boiling 0.1 mol ammonium molybdate solution at a dropping rate of 2 drops / second. During the dropping process, the ammonium molybdate solution is kept boiling. After the dropping is completed, the solution is boiled for 1 hour to obtain a trimetallic acid salt. The intermediate B and the trimetallic acid salt in a molar ratio of 3:1 are mixed and heated to 60°C for reaction for 72 hours. During the reaction, nitrogen is continuously introduced and the tail gas is introduced into dilute sulfuric acid. The molar ratio of the dilute sulfuric acid to the trimetallic acid salt is 1:0.06. The concentration of ammonium sulfate in the dilute sulfuric acid is detected. When the concentration is ≤1 mmol / L, the reaction is terminated. The solution is then dried by rotary evaporation at 80°C for 6 hours and finally dried in vacuum at 80°C for 72 hours to obtain an ionic liquid catalyst 1#.

[0094] Ionic Liquid Catalyst 2#

[0095] (1) Preparation of functional halogenated alkane monomer: 0.1 mol of 11-chloro-undecanoic acid and 0.11 mol of N-hydroxymethylnicotinamide were dissolved in a mixed solvent of ethanol and N,N-dimethylformamide (the volume ratio of ethanol to N,N-dimethylformamide was 1:1), and concentrated sulfuric acid accounting for 2 wt% of 11-chloro-undecanoic acid was added as a catalyst, and then reacted at 70° C. for 5 h to obtain a crude product, and the solvent was removed by vacuum distillation, and the product was extracted with ethyl acetate for 5 times and dried to obtain the product;

[0096] (2) Preparation of intermediate B: 0.08 mol of pyridine and 0.08 mol of functional halogenated alkane monomer were dissolved in a mixed solvent of ethanol and acetone (the volume ratio of ethanol and acetone was 1:1), heated under reflux for 22 h, and the solvent was removed by rotary evaporation. The mixture was extracted with a mixed solvent of ether and acetonitrile in a volume ratio of 1:1 for 5 times, and then dried to obtain intermediate A. Intermediate A was dissolved in ethanol and added to a flask filled with OH - In an ion exchange column of a strong alkaline anion exchange resin, ethanol is used for elution, and the strong alkaline eluate with a pH value greater than 8 is collected and dried at 80°C for 24 hours to obtain intermediate B;

[0097] (3) Preparation of ionic liquid catalyst: Hydrogen peroxide (hydrogen peroxide concentration is 30 wt%) accounting for 10 wt% of the weight of ammonium molybdate, 0.08 mol of nickel sulfate and 0.03 mol of manganese sulfate are added to deionized water, and then slowly added dropwise to a boiling 0.1 mol ammonium molybdate solution at a dropping rate of 1 drop / second. The ammonium molybdate solution is kept boiling during the dropping process. After the dropping is completed, the solution is boiled for 2 h to obtain a trimetallic acid salt. The intermediate B and the trimetallic acid salt in a molar ratio of 4:1 are mixed and heated to 70°C for reaction for 60 h. Nitrogen is continuously introduced during the reaction, and the tail gas is introduced into dilute sulfuric acid. The molar ratio of the dilute sulfuric acid to the trimetallic acid salt is 1:0.06. The concentration of ammonium sulfate in the dilute sulfuric acid is detected. When the concentration is ≤1 mmol / L, the reaction is terminated. The mixture is then rotary dried at 90°C for 4 h, and finally vacuum dried at 80°C for 72 h to obtain an ionic liquid catalyst 2#.

[0098] Ionic Liquid Catalyst 3#

[0099] (1) Preparation of functional halogenated alkane monomers: 0.1 mol of 9-bromononanoic acid and 0.11 mol of N-(benzylcarbonyloxy)hydroxylamine were dissolved in a mixed solvent of methanol and dimethyl sulfoxide (the volume ratio of methanol to dimethyl sulfoxide was 1:1), and concentrated sulfuric acid accounting for 2 wt% of 9-bromononanoic acid was added as a catalyst, and then reacted at 65° C. for 6 h to obtain a crude product, and the solvent was removed by reduced pressure distillation, and the product was extracted with ethyl acetate for 5 times and dried to obtain the product;

[0100] (2) Preparation of intermediate B: 0.08 mol of N-methylimidazole and 0.08 mol of functional halogenated alkane monomer were dissolved in a mixed solvent of methanol and chloroform (methanol and chloroform volume ratio was 1:1), heated to reflux for reaction for 22 h, and the solvent was removed by rotary evaporation. The mixture was extracted with a mixed solvent of ether and acetonitrile in a volume ratio of 1:1 for 5 times, and then dried to obtain intermediate A. Intermediate A was dissolved in methanol and added to a flask filled with OH - In an ion exchange column of a strong alkaline anion exchange resin, methanol is used for elution, and the strong alkaline eluate with a pH value greater than 8 is collected and dried at 80°C for 24 hours to obtain intermediate B;

[0101] (3) Preparation of ionic liquid catalyst: Hydrogen peroxide (hydrogen peroxide concentration is 30 wt%) accounting for 10% of the weight of ammonium molybdate, 0.06 mol of nickel sulfate and 0.04 mol of cobalt sulfate are added to deionized water, and then slowly added dropwise to a boiling 0.1 mol ammonium molybdate solution at a dropping rate of 2 drops / second. The ammonium molybdate solution is kept boiling during the dropping process. After the dropping is completed, the solution is boiled for 1.5 hours to obtain a trimetallic acid salt. The intermediate B and the trimetallic acid salt in a molar ratio of 4:1 are mixed and heated to 65°C for reaction for 70 hours. Nitrogen is continuously introduced during the reaction, and the tail gas is introduced into dilute sulfuric acid. The molar ratio of the dilute sulfuric acid to the trimetallic acid salt is 1:0.06. The concentration of ammonium sulfate in the dilute sulfuric acid is detected. When the concentration is ≤1 mmol / L, the reaction is terminated. The solution is then dried by rotary evaporation at 80°C for 6 hours, and finally dried in vacuum at 80°C for 72 hours to obtain an ionic liquid catalyst 3#.

[0102] Ionic liquid catalyst 4#

[0103] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that 5-hydroxytryptamine is used to replace N-(benzylcarbonyloxy)hydroxylamine, and the rest is the same as ionic liquid catalyst 3#.

[0104] Ionic Liquid Catalyst 5#

[0105] The difference between the present ionic liquid catalyst and the ionic liquid catalyst 3# is that N-benzylethanolamine is used to replace N-(benzylcarbonyloxy)hydroxylamine, and the rest is the same as the ionic liquid catalyst 3#.

[0106] Ionic Liquid Catalyst 6#

[0107] The difference between the present ionic liquid catalyst and the ionic liquid catalyst 3# is that N-methylpyrrole is used to replace N-methylimidazole, and the rest is the same as the ionic liquid catalyst 3#.

[0108] Ionic liquid catalyst 7#

[0109] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that 0.04 mol of N,N,N',N'-tetramethylethylenediamine is used to replace 0.08 mol of N-methylimidazole, and the rest is the same as ionic liquid catalyst 3#.

[0110] Ionic liquid catalyst 8#

[0111] The difference between this ionic liquid catalyst and ionic liquid catalyst 3# is that 0.04 mol of N,N,N',N'-tetramethyl-1,4-butanediamine is used to replace 0.08 mol of N-methylimidazole, and ethanol is used as the solvent instead of methanol. The rest is the same as ionic liquid catalyst 3#.

[0112] Ionic Liquid Catalyst 9#

[0113] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that 0.04 mol of N,N,N',N'-tetramethylhexanediamine is used to replace 0.08 mol of N-methylimidazole, and acetone is used as the solvent instead of chloroform. The rest is the same as ionic liquid catalyst 3#.

[0114] Ionic liquid catalyst 10#

[0115] The difference between the present ionic liquid catalyst and the ionic liquid catalyst 3# is that 0.04 mol of 4,4'-bipyridine is used to replace 0.08 mol of N-methylimidazole, and the rest is the same as the ionic liquid catalyst 3#.

[0116] Ionic liquid catalyst 11#

[0117] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that in step (3), the cobalt sulfate is replaced by nickel sulfate (0.1 mol of nickel sulfate), and the rest is the same as ionic liquid catalyst 3#.

[0118] Ionic liquid catalyst 12#

[0119] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that in step (3), nickel sulfate is replaced by cobalt sulfate (0.1 mol of cobalt sulfate), and the rest is the same as ionic liquid catalyst 3#.

[0120] Ionic liquid catalyst 13#

[0121] The difference between the present ionic liquid catalyst and ionic liquid catalyst 3# is that in step (3), nickel sulfate is replaced by manganese sulfate, and the rest is the same as ionic liquid catalyst 3#.

[0122] Comparison of ionic liquid catalyst D1#

[0123] The difference between the comparative ionic liquid catalyst and ionic liquid catalyst 3# is that dodecane bromide is used to replace the functional halogenated alkane monomer synthesized in step (1), and the rest is the same as ionic liquid catalyst 3#.

[0124] Comparison of ionic liquid catalyst D2#

[0125] The difference between the comparative ionic liquid catalyst and the ionic liquid catalyst 3# is that a monometallic salt is used in step (3) instead of a trimetallic salt to synthesize a monometallic ionic liquid catalyst. The specific steps of step (3) are as follows: an equal amount of hydrogen peroxide to the ionic liquid catalyst 3# is added to deionized water, and then slowly dripped into a boiling 0.1 mol ammonium molybdate solution at a dripping rate of 2 drops / second. During the dripping process, the ammonium molybdate solution is kept boiling. After the dripping is completed, the solution is continued to boil for 1.5 hours, that is, To obtain molybdenum metal salt, the intermediate B and molybdenum metal salt in a molar ratio of 4:1 were mixed and heated to 65°C for reaction for 70 hours. Nitrogen was continuously introduced during the reaction, and the tail gas was introduced into dilute sulfuric acid. The molar ratio of dilute sulfuric acid to molybdic acid was 1:0.06. The concentration of ammonium sulfate in dilute sulfuric acid was detected. When the concentration was ≤1mmol / L, the reaction was terminated. Thereafter, the catalyst was dried by rotary evaporation at 80°C for 6 hours, and finally dried in vacuum at 80°C for 72 hours to obtain comparative ionic liquid catalyst D2#. The rest was the same as ionic liquid catalyst 3#.

[0126] Example 3

[0127] A method for obtaining renewable fuel by hydrogenating waste oil and fat using the system for producing renewable fuel by treating waste oil and fat through hot oil circulation of Example 1, wherein the ionic liquid catalyst used in this example is the ionic liquid catalyst prepared in Example 2. The specific differences in the treatment methods are shown in Table 1 below, where "-" in Table 1 represents the same as method 4. The density of the circulating oil used is 0.76-0.82 ml / g, and it is a biomass hydrocarbon compound with a cetane index of more than 80.

[0128] Table 1

[0129]

[0130] Test Case

[0131] The hydrocarbon-based biodiesel, naphtha and kerosene prepared by the methods of Example 3 were calculated, and each oil product was tested. The test results are shown in Tables 2-4 below.

[0132] Table 2 Hydrocarbon-based biodiesel

[0133]

[0134] The C15-C18 alkane content in Table 2 is tested and calculated according to SH / T 0410, and the index is ≥70% to be qualified; the sulfur content is tested and calculated according to GB / T 34100, and the index is ≤10mg / kg to be qualified; the total pollutant content refers to the content of all pollutants including metal ions, impurities and phospholipids, and is tested and calculated according to GB / T33400, and the index is ≤24mg / kg to be qualified; the acidity is measured in KOH, and is tested and calculated according to GB / T7304, and the index is ≤5mg / 100ml to be qualified; the oxidation stability is measured in total insoluble matter, and is tested and calculated according to SH / T 0175, and the index is ≤2.5mg / 100ml to be qualified.

[0135] Table 3 Naphtha

[0136]

[0137] The sulfur content in Table 3 is tested and calculated according to SH / T 0689, and the index is qualified when ≤10mg / kg; the iron content is tested and calculated according to SH / T 0712, and the index is qualified when ≤0.01g / L; the colloid content is tested and calculated according to GB / T8019, and the unwashed solvent colloid content is qualified when ≤30mg / 100ml; the phosphorus content is tested and calculated according to SH / T0020, and the index is qualified when ≤0.0002. The "-" in Table 3 means that it was not measured.

[0138] Table 4 Kerosene

[0139]

[0140]

[0141] The halogen content in Table 4 is tested and calculated according to ASTM D7359, and the index is qualified when it is ≤1mg / kg; the metal content refers to the total content of aluminum, calcium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, lead, palladium, platinum, tin, strontium, titanium, vanadium and zinc, which is tested and calculated according to NB / SH / T 0892, and the content of each metal is qualified when it is ≤0.1mg / kg. There are a total of 22 metal elements mentioned above, so the metal content in Table 4 is qualified when it is ≤2.2mg / kg; the sulfur content is tested and calculated according to SH / T 2689, and the index is qualified when it is ≤15mg / kg; the acid value is tested and calculated according to GB / T 12574, and the index is qualified when it is ≤0.015mgKOH / g.

[0142] According to the above data, the ionic liquid catalyst prepared in the present application can catalyze the catalytic hydrogenation of waste oils and fats to obtain naphtha, kerosene and hydrocarbon-based biodiesel, wherein the total yields of the three products are: method 1 is 87.1%, method 2 is 86.2%, method 3 is 86.3%, method 4 is 86.9%, method 5 is 83.9%, method 6 is 84.2%, method 7 is 86.3%, method 8 is 87.3%, method 9 is 87.7%, method 10 is 87.8%, method 11 is 87.4%, method 12 is 84.4%, method 13 is 84.3%, method 14 is 84.2%, method 15 is 83.0%, method 16 is 83.2%, and method 17 is 83.6%. It is proved that the use of ionic liquid catalyst to catalyze waste grease in the present application can generate great economic benefits. At the same time, the above methods can be carried out in batch production in the system of Example 1 without causing coking of the equipment and without the need to add pretreatment agents to the waste grease for additional pretreatment, thereby reducing the cost of waste grease recycling and improving the convenience and controllability of the process.

[0143] According to the comparison between method 4 and methods 5 and 6, the type of functional monomer containing hydroxyl groups can change the type of functional groups in the long chain carried by the ionic liquid catalyst, thereby affecting the catalytic efficiency of the ionic liquid catalyst and the removal effect of metal ions, impurities and phospholipids.

[0144] According to the comparison between Method 7-Method 11 and Method 4, the type of tertiary amine monomer in the ionic liquid catalyst will also affect the catalytic efficiency and the removal effect on metal ions, impurities and phospholipids. The tertiary amine monomers used in Method 8-Method 11 all contain two tertiary amines, thereby forming two quaternary ammonium salt groups. Compared with the tertiary amine monomer with only one tertiary amine, it has higher catalytic activity and better removal effect on metal ions, impurities and phospholipids.

[0145] According to the comparison between methods 12, 13 and 4, when intermediate B remains unchanged, the simple molybdenum-cobalt catalyst and molybdenum-nickel catalyst bimetallic acid salt will reduce the catalytic efficiency of the ionic liquid catalyst under the same catalytic conditions, and the removal effect of metal ions, impurities and phospholipids will also decrease compared with the molybdenum-nickel-cobalt trimetallic acid salt. Therefore, the trimetallic acid salt with a third metal added based on molybdenum-nickel in the present application has a better coordination effect with intermediate B; according to the comparison between methods 14 and 4, it can be seen that by replacing the molybdenum-manganese base metal with the molybdenum-nickel base metal, even at the same content and the coordination of the third catalytic metal, its catalytic activity and the removal effect of metal ions, impurities and phospholipids are reduced, thereby proving that the trimetallic salt of the present application makes full use of the catalytic properties of molybdenum-nickel to obtain the best catalytic effect; according to the comparison between methods 16 and 4, the catalytic efficiency of the ionic liquid catalyst D2# formed by the single metal and the intermediate B decreases more, and the removal effect of metal ions, impurities and phospholipids decreases more than that of the dimetallic acid salt of method 12.

[0146] According to the comparison between method 15 and method 4, the ionic liquid catalyst prepared by the present application using the synthetic functional halogenated alkane monomer can significantly improve the catalytic efficiency of waste oil and improve the removal effect of metal ions, impurities and phospholipids compared to the ionic liquid catalyst prepared by ordinary long-chain halogenated alkane, and is more suitable for industrial catalysis of waste oil to produce renewable fuels such as second-generation biodiesel. In addition, as the process proceeds, the coking rate of method 15 is significantly higher than that of method 4. When the comparative ionic liquid catalyst D1# is used to hydrogenate waste oil to produce second-generation biodiesel, it is necessary to shut down the system after a certain period of operation, and clean the coking area before it can be used normally. The production efficiency is significantly reduced compared to method 4.

[0147] According to the comparison between Method 17 and Method 4, the decrease in the proportion of circulating oil will lead to a decrease in the dilution effect of the raw waste oil, which will lead to a decrease in the dispersion effect of the ionic liquid catalyst in the waste oil, and then the catalytic efficiency and the removal effect of metal ions, impurities and phospholipids will all decrease. In addition, Method 17 is the same as Method 15. As the process progresses, the coking rate increases significantly compared to Method 4. It is necessary to stop the system after a certain period of operation to clean the coking area. It is an intermittent production, and the production efficiency is significantly reduced compared to Method 4.

[0148] The above description is only an embodiment of the present application. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an ionic liquid catalyst for producing renewable fuel from waste oils and fats, characterized in that: The steps include: (1) Preparation of functional halogenated alkane monomers: a halogenated alkane containing a carboxyl group and a functional monomer containing a hydroxyl group are reacted and treated to obtain a functional halogenated alkane monomer, wherein the functional monomer containing a hydroxyl group is at least one selected from the group consisting of N-cyclohexylhydroxylamine, N-(benzylcarbonyloxy)hydroxylamine, N-hydroxymethylnicotinamide, 5-hydroxytryptamine, and N-benzylethanolamine; (2) Preparation of intermediate B: reacting a monomer containing a tertiary amine with a functional halogenated alkane monomer, treating the monomer to obtain intermediate A, and treating intermediate A with a strong alkaline anion exchange resin to obtain intermediate B; (3) Preparation of ionic liquid catalyst: The intermediate B and the polymetallic acid salt are mixed and heated to react, and then dried to obtain the ionic liquid catalyst.

2. The method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat according to claim 1, characterized in that the number of carbon atoms of the halogenated alkane containing a carboxyl group is 6-11; Preferably, the carboxyl-containing halogenated alkane is selected from at least one of 6-chlorohexanoic acid, 7-chloroheptanoic acid, 8-chlorooctanoic acid, 9-chlorononanoic acid, 10-chlorodecanoic acid, 11-chloro-undecanoic acid, 6-bromohexanoic acid, 7-bromoheptanoic acid, 8-bromooctanoic acid, 9-bromononanoic acid, 10-bromodecaneic acid, and 11-bromo-undecanoic acid.

3. The method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat according to claim 1, characterized in that the functional monomer containing a hydroxyl group is selected from N-(benzylcarbonyloxy)hydroxylamine.

4. The method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat according to claim 1, characterized in that the monomer containing a tertiary amine is selected from at least one of trihexylamine, triheptylamine, trioctylamine, pyridine, N-methylimidazole, N-methylpyrrole, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethylhexanediamine, and 4,4'-bipyridine.

5. The method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat according to claim 1, characterized in that the polymetallic acid salt is a trimetallic acid salt comprising at least molybdenum and nickel metals; Preferably, the trimetallic acid salt is selected from at least one of molybdenum nickel cobaltate, molybdenum nickel manganate, and molybdenum nickel zincate; More preferably, the preparation method of the trimetallic acid salt is: Hydrogen peroxide, nickel sulfate and a third metal sulfate are added to deionized water, and then slowly added dropwise to a boiling ammonium molybdate solution. During the dropping process, the ammonium molybdate solution is kept boiling. After the dropping is completed, the solution is boiled for 1-2 hours to obtain a trimetallic acid salt. The third metal sulfate is selected from one of cobalt sulfate, manganese sulfate or zinc sulfate.

6. The ionic liquid catalyst prepared by the method for preparing an ionic liquid catalyst for producing renewable fuel from waste oil and fat according to any one of claims 1 to 5.

7. A method for producing renewable fuel by treating waste oil with an ionic liquid catalyst, characterized in that: The steps include: S1: Mix circulating oil, waste grease and ionic liquid catalyst in a weight ratio of (1-6): 1: (0.002-0.005) are mixed to form a premix, and then the mixture is heated to 280-380°C and enters the first reactor (4) for hydrogenation catalysis, wherein the ionic liquid catalyst is an ionic liquid catalyst prepared by the preparation method according to claim 1; S2: The gaseous effluent of the first reactor (4) enters the second reactor (5) for further hydrogenation catalysis to obtain reactants and circulating oil, and the bottom effluent of the first reactor (4) enters the ash discharge hot high-pressure separator (14) to discharge waste containing high-ash oil and tailings; S3: The reactants flow out to the hot high-pressure separator (7) to separate into gas phase A and liquid phase A. The gas phase A enters the cold high-pressure separator (16) to separate circulating hydrogen, combined distillate oil and residual oil. A portion of the liquid phase A is used as circulating oil, and the other portion enters the hot low-pressure separator (8) to separate waste containing high-ash oil and tailings and liquid phase B. S4: Liquid phase B enters the fractionation tower (10) for fractionation to obtain renewable fuel.

8. The method for producing renewable fuel by treating waste oil with an ionic liquid catalyst according to claim 7, characterized in that: The temperature of the premix after heating is 300-360°C; The waste grease includes at least one of acidified oil, kitchen waste grease, sewage oil and animal fat; The acid value of the waste oil is greater than 40 mgKOH / g; The renewable fuel includes biodiesel and / or biojet fuel; Preferably, the renewable fuel includes hydrocarbon-based biodiesel, naphtha and kerosene.

9. The method for producing renewable fuel by treating waste oil and fat with an ionic liquid catalyst according to claim 7, characterized in that: The circulating oil has a density of 0.76-0.82 ml / g and is a biomass hydrocarbon compound with a cetane index of more than 80.

10. Use of the method for producing renewable fuel by treating waste oil with an ionic liquid catalyst as claimed in any one of claims 7 to 9 in the preparation of bioenergy, biodiesel and bio-jet fuel.

Images