High-calorific-value biodiesel based on modified formula and preparation method of high-calorific-value biodiesel

Abstract

The invention relates to the technical field of biodiesel, in particular to high-calorific-value biodiesel based on a modified formula and a preparation method thereof.The preparation method comprises the following steps that S1, catering waste grease is pretreated, and pretreated catering waste grease is obtained; s2, carrying out esterification treatment on the pretreated catering waste grease, and adopting a composite treatment agent in the treatment process to obtain a crude product; s3, the crude product is subjected to catalytic cracking quality improvement, and a cracking product is obtained; s4, carrying out hydrogenation saturation treatment on the cracking product to obtain a mixed alkane product; and S5, carrying out purification and fractionation on the mixed alkane product to obtain the high-calorific-value biodiesel. According to the invention, after oil and alcohol are adsorbed into the spaces, the concentration of reactants is locally improved, and the reactants are limited around acidic sites, so that the reaction efficiency is greatly improved, the conversion efficiency of the biodiesel is effectively improved, and the calorific value performance of the biodiesel is further improved.

Description

Technical Field

[0001] This invention relates to the field of biodiesel technology, specifically to a high-calorific-value biodiesel based on a modified formulation and its preparation method. Background Technology

[0002] Biodiesel, a renewable and clean liquid fuel, is produced through processes such as transesterification and catalytic cracking. It can effectively replace petrochemical diesel and alleviate the energy crisis and environmental pollution problems.

[0003] In existing technologies, biodiesel production typically uses relatively simple raw materials, resulting in low material utilization and affecting the calorific value of the biodiesel. Therefore, this invention provides a high-calorific-value biodiesel based on a modified formulation and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a high-calorific-value biodiesel based on a modified formulation and its preparation method. The biodiesel prepared by this invention has a high calorific value, which effectively improves the performance of biodiesel.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing high-calorific-value biodiesel based on a modified formulation includes the following steps: S1: Pretreatment, pretreatment of waste cooking oil to obtain pretreated waste cooking oil; S2: Esterification treatment, which involves esterifying pretreated waste cooking oil. A composite treatment agent is used in the process to obtain a crude product. S3: Refining process, refining the crude product to obtain high-calorific-value biodiesel based on modified formulation; The refining process includes the following steps: A. Separation process: The crude product undergoes separation processing to obtain the preparatory material; B. Dehydration and purification treatment: The prepared material is dehydrated and purified to obtain the base material; C. Adsorption treatment: The base material is subjected to adsorption treatment to complete the final refining process and obtain high-calorific-value biodiesel based on the modified formula.

[0006] The composite treatment agent comprises the following raw materials in parts by weight: 40-60 parts powder, 8-12 parts dopamine hydrochloride, 9.5-14.5 parts epichlorohydrin, and 0.3-0.8 parts initiator.

[0007] Furthermore, the pretreatment method for the waste cooking oil is as follows: the recovered waste cooking oil is centrifuged at 3000-4000 rpm for 10-20 min, the solid impurities at the bottom are discarded, and the separated oily substance is mixed with 2-4% anhydrous magnesium sulfate by mass. The mixture is stirred at 150-200 rpm for 30-50 min, then allowed to stand for 20-30 min, and filtered through a 200-mesh filter to obtain the pretreated waste cooking oil, wherein the anhydrous magnesium sulfate has a particle size of 100 μm.

[0008] Furthermore, the preparation method of the composite treatment agent is as follows: the powder is dispersed in deionized water at a solid-liquid ratio of 1:20, dopamine hydrochloride is added, and the mixture is stirred at 20-30℃ for 22-26 hours. Then epichlorohydrin is added, the temperature is raised to 55-65℃, and the mixture is stirred for 2.8-3.2 hours. Finally, an initiator and acrylic acid of equal mass to epichlorohydrin are added, the temperature is raised to 65-75℃, and the mixture is stirred for 3.8-4.2 hours. After the reaction, the mixture is transferred to a centrifuge and centrifuged at 3500-4500 rpm for 15-25 minutes. The solid product is collected and washed three times with deionized water at 5 times the mass of the solid product. The final solid product is placed in a vacuum drying oven and vacuum dried at 55-65℃ for 10-14 hours to obtain the composite treatment agent.

[0009] Furthermore, the dopamine hydrochloride has a particle size of 150 μm, the epichlorohydrin has a purity greater than 99%, and the initiator is ammonium persulfate with a particle size of 100 μm.

[0010] Furthermore, the preparation method of the powder is as follows: the mixture is added to a 55-60% fuming sulfuric acid aqueous solution at a mass ratio of (8-10):1, and stirred at 100-200 rpm for 2.5-3.5 h at 35-45℃. After the reaction, the product is slowly poured into ice water to quench it. The pH of the system is adjusted to 2-3 with a sodium bicarbonate solution of 8-10% by mass. The solid product is collected by filtration, washed with deionized water until neutral, and vacuum dried at 55-65℃ for 8-10 h to obtain the powder.

[0011] Further, the preparation method of the mixture is as follows: Konjac glucomannan powder is added to an ethanol aqueous solution with a mass fraction of 5-7% at a mass ratio of 1:(10-15), stirred at 100-150 rpm for 1-1.5 h at 20-30℃, filtered, and dried at 100-110℃ for 3-4 h to obtain refined konjac glucomannan. The refined konjac glucomannan is mixed with chitosan oligosaccharide at a mass ratio of (5-10):1, and a 10% mass concentration sodium hydroxide solution accounting for 8-10% of the mass of the refined konjac glucomannan is added. The mixture is stirred and activated at 70-80℃ for 1.5-2 h, filtered and washed until neutral, and dried at 100-110℃ to constant weight to obtain the mixture, wherein the particle size of the konjac glucomannan is 150 μm.

[0012] Furthermore, the esterification treatment method is as follows: a composite treatment agent and methanol are added to the pretreated waste cooking oil, and concentrated sulfuric acid with a mass fraction of 98% is slowly added dropwise. The mixture is stirred at 150-250 rpm for 3.5-4.5 hours at 65-70°C to obtain a crude product. The mass of the composite treatment agent is 5-8% of the mass of the pretreated waste cooking oil, the volume of methanol is 20-25% of the volume of the pretreated waste cooking oil, and the amount of concentrated sulfuric acid added is 1-2% of the mass of the pretreated waste cooking oil.

[0013] Furthermore, the separation process is as follows: the crude product is transferred to a separatory device, washed with hot water at 60-70°C, allowed to stand and separate, the lower aqueous phase is separated and discarded, the resulting oil phase is washed repeatedly until it is neutral, the washed oil phase is allowed to stand and separate for 8-12 hours, the lower glycerol phase is separated and removed, the separation process is completed, and the prepared material is obtained.

[0014] Furthermore, the dehydration and purification process is as follows: 2% anhydrous sodium sulfate is added to the prepared material, and the mixture is stirred at 200-300 rpm for 20-30 min. After filtration, the filtrate is obtained. The filtrate is then subjected to vacuum distillation at -0.095 MPa and 90°C to complete the dehydration and purification process and obtain the base material. The adsorption treatment method is as follows: the base material is passed through a composite adsorption column containing activated alumina and fine-pore silica gel to complete the adsorption treatment, thereby obtaining high-calorific-value biodiesel based on the modified formula.

[0015] Furthermore, a high-calorific-value biodiesel based on a modified formulation is prepared by a method for preparing high-calorific-value biodiesel based on a modified formulation.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, during the preparation of biodiesel, a composite treatment agent is loaded with oils and methanol. After the reaction, the used composite treatment agent is removed from the crude product through separation. The sulfonated modified konjac glucomannan and chitosan oligosaccharide complex in the composite treatment agent form a framework with high specific surface area and porosity. Through physical adsorption, it captures and accommodates oil and methanol molecules, which is equivalent to fixing the reactants on the catalyst surface, improving the binding efficiency. Dopamine hydrochloride undergoes self-polymerization on the powder surface to form a polydopamine coating, which is more compatible with polar methanol and non-polar oils. Epichlorohydrin, as a crosslinking agent, and acrylic acid, as a functional monomer, copolymerize under the action of an initiator, crosslinking the preceding framework material and polydopamine coating into a stable three-dimensional network structure of solid particles. After the oil and alcohol are adsorbed into these spaces, the reactant concentration is locally increased and confined around the acidic sites, which greatly improves the reaction efficiency, thereby effectively improving the conversion efficiency of biodiesel and thus improving the calorific value performance of biodiesel. Attached Figure Description

[0017] Figure 1 The present invention provides a flowchart of a high-calorific-value biodiesel based on a modified formulation and its preparation method. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0020] Example 1:

[0021] S1: Pretreatment, pretreatment of waste cooking oil to obtain pretreated waste cooking oil; The pretreatment method for waste cooking oil is as follows: the recycled waste cooking oil is centrifuged at 3000 rpm for 10 min, the solid impurities at the bottom are discarded, and the separated oily substance is mixed with 2% anhydrous magnesium sulfate by mass. The mixture is stirred at 150 rpm for 50 min, then allowed to stand for 20 min, and filtered through a 200-mesh filter to obtain the pretreated waste cooking oil. The anhydrous magnesium sulfate has a particle size of 100 μm. S2: Esterification treatment, which involves esterifying pretreated waste cooking oil. A composite treatment agent is used in the process to obtain a crude product. The esterification treatment method is as follows: a compound treatment agent and methanol are added to the pretreated waste cooking oil, and concentrated sulfuric acid with a mass fraction of 98% is slowly added dropwise. The mixture is stirred at 150 rpm for 3.5 hours at 65°C to obtain a crude product. The mass of the compound treatment agent is 5% of the mass of the pretreated waste cooking oil, the volume of methanol is 20% of the volume of the pretreated waste cooking oil, and the addition of concentrated sulfuric acid is 1% of the mass of the pretreated waste cooking oil. S3: Refining process, refining the crude product to obtain high-calorific-value biodiesel based on modified formulation; The refining process includes the following steps: A. Separation process: The crude product undergoes separation processing to obtain the preparatory material; The separation process is as follows: the crude product is transferred to a separatory device, washed with hot water at 60°C, allowed to stand and separate, the lower aqueous phase is separated and discarded, the resulting oil phase is washed repeatedly until it is neutral, the washed oil phase is allowed to stand and separate for 8 hours, the lower glycerol phase is separated and removed, the separation process is completed, and the prepared material is obtained. B. Dehydration and purification treatment: The prepared material is dehydrated and purified to obtain the base material; The dehydration and purification process is as follows: 2% anhydrous sodium sulfate is added to the prepared material, and the mixture is stirred at 200 rpm for 20 min. After filtration, the filtrate is obtained. The filtrate is then subjected to vacuum distillation at -0.095 MPa and 90 °C to complete the dehydration and purification process and obtain the base material. C. Adsorption treatment: The base material is subjected to adsorption treatment to complete the final refining process and obtain high-calorific-value biodiesel based on the modified formula; The adsorption treatment method is as follows: the base material is passed through a composite adsorption column containing activated alumina and fine-pore silica gel to complete the adsorption treatment and obtain high-calorific-value biodiesel based on the modified formula. The composite treatment agent comprises the following raw materials in parts by weight: 40 parts powder, 8 parts dopamine hydrochloride, 9.5 parts epichlorohydrin, and 0.3 parts initiator; The preparation method of the composite treatment agent is as follows: the powder is dispersed in deionized water at a solid-liquid ratio of 1:20, dopamine hydrochloride is added, and the mixture is stirred at 20°C for 22 hours. Then epichlorohydrin is added, the temperature is raised to 55°C, and the mixture is stirred for 2.8 hours. Finally, an initiator and acrylic acid of equal mass to epichlorohydrin are added, the temperature is raised to 65°C, and the mixture is stirred for 3.8 hours. After the reaction, the mixture is transferred to a centrifuge and centrifuged at 3500 rpm for 15 minutes. The solid product is collected and washed three times with deionized water at a mass of 5 times that of the solid product. The final solid product is placed in a vacuum drying oven and vacuum dried at 55°C for 10 hours to obtain the composite treatment agent. The particle size of dopamine hydrochloride is 150 μm, the purity of epichlorohydrin is greater than 99%, and the initiator is ammonium persulfate with a particle size of 100 μm. The preparation method of the powder is as follows: the mixture is added to a 55% fuming sulfuric acid aqueous solution at a mass ratio of (8):1, and stirred at 100 rpm for 2.5 h at 35°C. After the reaction, the product is slowly poured into ice water to quench it. The pH of the system is adjusted to 2 with an 8% sodium bicarbonate solution. The solid product is collected by filtration, washed with deionized water until neutral, and vacuum dried at 55°C for 8 h to obtain the powder. The preparation method of the mixture is as follows: Konjac glucomannan powder is added to 5% ethanol aqueous solution at a mass ratio of 1: (10), stirred at 100 rpm for 1 h at 20°C, filtered and dried at 100°C for 3 h to obtain refined konjac glucomannan. The refined konjac glucomannan is mixed with chitosan oligosaccharide at a mass ratio of (5): 1, and 10% sodium hydroxide solution at a mass concentration of 8% of the refined konjac glucomannan is added. The mixture is stirred and activated at 70°C for 1.5 h, filtered and washed until neutral, and dried at 100°C to constant weight to obtain the mixture. The particle size of the konjac glucomannan is 150 μm.

[0022] Example 2:

[0023] S1: Pretreatment, pretreatment of waste cooking oil to obtain pretreated waste cooking oil; The pretreatment method for waste cooking oil is as follows: the recycled waste cooking oil is centrifuged at 3500 rpm for 15 min, the solid impurities at the bottom are discarded, and the separated oily substance is mixed with 3% anhydrous magnesium sulfate by mass. The mixture is stirred at 175 rpm for 40 min, then allowed to stand for 25 min, and filtered through a 200-mesh filter to obtain the pretreated waste cooking oil. The anhydrous magnesium sulfate has a particle size of 100 μm. S2: Esterification treatment, which involves esterifying pretreated waste cooking oil. A composite treatment agent is used in the process to obtain a crude product. The esterification treatment method is as follows: a compound treatment agent and methanol are added to the pretreated waste cooking oil, and concentrated sulfuric acid with a mass fraction of 98% is slowly added dropwise. The mixture is stirred at 200 rpm for 4 hours at 67°C to obtain a crude product. The mass of the compound treatment agent is 6% of the mass of the pretreated waste cooking oil, the volume of methanol is 23% of the volume of the pretreated waste cooking oil, and the addition of concentrated sulfuric acid is 1.5% of the mass of the pretreated waste cooking oil. S3: Refining process, refining the crude product to obtain high-calorific-value biodiesel based on modified formulation; The refining process includes the following steps: A. Separation process: The crude product undergoes separation processing to obtain the preparatory material; The separation process is as follows: the crude product is transferred to a separatory device, washed with hot water at 65°C, allowed to stand and separate, the lower aqueous phase is separated and discarded, the resulting oil phase is washed repeatedly until it is neutral, the washed oil phase is allowed to stand and separate for 10 hours, the lower glycerol phase is separated and removed, the separation process is completed, and the prepared material is obtained. B. Dehydration and purification treatment: The prepared material is dehydrated and purified to obtain the base material; The dehydration and purification process is as follows: 2% anhydrous sodium sulfate is added to the prepared material, and the mixture is stirred at 250 rpm for 25 min. After filtration, the filtrate is obtained. The filtrate is then subjected to vacuum distillation at -0.095 MPa and 90 °C to complete the dehydration and purification process and obtain the base material. C. Adsorption treatment: The base material is subjected to adsorption treatment to complete the final refining process and obtain high-calorific-value biodiesel based on the modified formula; The adsorption treatment method is as follows: the base material is passed through a composite adsorption column containing activated alumina and fine-pore silica gel to complete the adsorption treatment and obtain high-calorific-value biodiesel based on the modified formula. The composite treatment agent comprises the following raw materials in parts by weight: 50 parts powder, 10 parts dopamine hydrochloride, 12 parts epichlorohydrin, and 0.5 parts initiator; The preparation method of the composite treatment agent is as follows: the powder is dispersed in deionized water at a solid-liquid ratio of 1:20, dopamine hydrochloride is added, and the mixture is stirred at 25°C for 24 hours. Then epichlorohydrin is added, the temperature is raised to 60°C, and the mixture is stirred for 3 hours. Finally, an initiator and acrylic acid of equal mass to epichlorohydrin are added, the temperature is raised to 70°C, and the mixture is stirred for 4 hours. After the reaction, the mixture is transferred to a centrifuge and centrifuged at 4000 rpm for 20 minutes. The solid product is collected and washed three times with deionized water at a mass of 5 times that of the solid product. The final solid product is placed in a vacuum drying oven and vacuum dried at 60°C for 12 hours to obtain the composite treatment agent. The particle size of dopamine hydrochloride is 150 μm, the purity of epichlorohydrin is greater than 99%, and the initiator is ammonium persulfate with a particle size of 100 μm. The preparation method of the powder is as follows: the mixture is added to a 57% fuming sulfuric acid aqueous solution at a mass ratio of (9):1, stirred at 150 rpm for 3 h at 40°C, and stirred at 150 rpm for 3 h at 40°C. After the reaction, the product is slowly poured into ice water to quench it. The pH of the system is adjusted to 2.5 with a 9% sodium bicarbonate solution. The solid product is collected by filtration, washed with deionized water until neutral, and vacuum dried at 60°C for 9 h to obtain the powder. The preparation method of the mixture is as follows: Konjac glucomannan powder is added to 6% ethanol aqueous solution at a mass ratio of 1:(12), stirred at 150 rpm for 1.2 h at 25℃, filtered and dried at 105℃ for 3.5 h to obtain refined konjac glucomannan. The refined konjac glucomannan is mixed with chitosan oligosaccharide at a mass ratio of (7):1, and 10% sodium hydroxide solution with a mass concentration of 9% of the refined konjac glucomannan is added. The mixture is stirred and activated at 75℃ for 1.7 h, filtered and washed until neutral, and dried at 105℃ to constant weight to obtain the mixture. The particle size of konjac glucomannan is 150 μm.

[0024] Example 3:

[0025] S1: Pretreatment, pretreatment of waste cooking oil to obtain pretreated waste cooking oil; The pretreatment method for waste cooking oil is as follows: the recycled waste cooking oil is centrifuged at 4000 rpm for 20 min, the solid impurities at the bottom are discarded, and the separated oily substance is mixed with 4% anhydrous magnesium sulfate by mass. The mixture is stirred at 200 rpm for 50 min, then allowed to stand for 30 min, and filtered through a 200-mesh filter to obtain the pretreated waste cooking oil. The anhydrous magnesium sulfate has a particle size of 100 μm. S2: Esterification treatment, which involves esterifying pretreated waste cooking oil. A composite treatment agent is used in the process to obtain a crude product. The esterification treatment method is as follows: a compound treatment agent and methanol are added to the pretreated waste cooking oil, and concentrated sulfuric acid with a mass fraction of 98% is slowly added dropwise. The mixture is stirred at 250 rpm for 4.5 hours at 70°C to obtain a crude product. The mass of the compound treatment agent is 8% of the mass of the pretreated waste cooking oil, the volume of methanol is 25% of the volume of the pretreated waste cooking oil, and the addition of concentrated sulfuric acid is 2% of the mass of the pretreated waste cooking oil. S3: Refining process, refining the crude product to obtain high-calorific-value biodiesel based on modified formulation; The refining process includes the following steps: A. Separation process: The crude product undergoes separation processing to obtain the preparatory material; The separation process is as follows: the crude product is transferred to a separatory device, washed with hot water at 70°C, allowed to stand and separate, the lower aqueous phase is separated and discarded, the resulting oil phase is washed repeatedly until it is neutral, the washed oil phase is allowed to stand and separate for 12 hours, the lower glycerol phase is separated and removed, the separation process is completed, and the prepared material is obtained. B. Dehydration and purification treatment: The prepared material is dehydrated and purified to obtain the base material; The dehydration and purification process is as follows: 2% anhydrous sodium sulfate is added to the prepared material, and the mixture is stirred at 300 rpm for 30 min. After filtration, the filtrate is obtained. The filtrate is then subjected to vacuum distillation at -0.095 MPa and 90 °C to complete the dehydration and purification process and obtain the base material. C. Adsorption treatment: The base material is subjected to adsorption treatment to complete the final refining process and obtain high-calorific-value biodiesel based on the modified formula; The adsorption treatment method is as follows: the base material is passed through a composite adsorption column containing activated alumina and fine-pore silica gel to complete the adsorption treatment and obtain high-calorific-value biodiesel based on the modified formula. The composite treatment agent comprises the following raw materials in parts by weight: 60 parts powder, 12 parts dopamine hydrochloride, 14.5 parts epichlorohydrin, and 0.8 parts initiator; The preparation method of the composite treatment agent is as follows: the powder is dispersed in deionized water at a solid-liquid ratio of 1:20, dopamine hydrochloride is added, and the mixture is stirred at 30°C for 26 hours. Then epichlorohydrin is added, the temperature is raised to 65°C, and the mixture is stirred for 3.2 hours. Finally, an initiator and acrylic acid of equal mass to epichlorohydrin are added, the temperature is raised to 75°C, and the mixture is stirred for 4.2 hours. After the reaction, the mixture is transferred to a centrifuge and centrifuged at 4500 rpm for 25 minutes. The solid product is collected and washed three times with deionized water at a mass of 5 times that of the solid product. The final solid product is placed in a vacuum drying oven and vacuum dried at 65°C for 14 hours to obtain the composite treatment agent. The particle size of dopamine hydrochloride is 150 μm, the purity of epichlorohydrin is greater than 99%, and the initiator is ammonium persulfate with a particle size of 100 μm. The preparation method of the powder is as follows: the mixture is added to a 60% fuming sulfuric acid aqueous solution at a mass ratio of (10):1, stirred at 200 rpm at 45°C for 3.5 h, and stirred at 200 rpm at 45°C for 3.5 h. After the reaction, the product is slowly poured into ice water to quench it, and the pH of the system is adjusted to 3 with a 10% sodium bicarbonate solution. The solid product is collected by filtration, washed with deionized water until neutral, and vacuum dried at 65°C for 10 h to obtain the powder. The preparation method of the mixture is as follows: Konjac glucomannan powder is added to 7% ethanol aqueous solution at a mass ratio of 1:(15), stirred at 150 rpm for 1.5 h at 30°C, filtered and dried at 110°C for 4 h to obtain refined konjac glucomannan. The refined konjac glucomannan is mixed with chitosan oligosaccharide at a mass ratio of (10):1, and 10% sodium hydroxide solution at a mass concentration of 10% of the refined konjac glucomannan is added. The mixture is stirred and activated at 80°C for 2 h, filtered and washed until neutral, and dried at 110°C to constant weight to obtain the mixture, wherein the particle size of konjac glucomannan is 150 μm.

[0026] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain a composite treatment agent.

[0027] Comparative Example 2 differs from Example 1 in that the composite treatment agent in this comparative example contains only powder.

[0028] Comparative Example 3 differs from Example 1 in that no pretreatment is performed on the waste cooking oil in this comparative example.

[0029] Performance testing: The high-calorific-value biodiesel prepared based on the modified formulations in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing, and the test data are recorded in the table below: Table 1 Testing items cetane number Calorific value (MJ / kg) Example 1 77 45.9 Example 2 79 46.3 Example 3 76 46.1 Comparative Example 1 62 40.8 Comparative Example 2 68 42.7 Comparative Example 3 70 43.5 In performance testing, The cetane number test shall be conducted in accordance with GB386-2021; The calorific value data of the high-calorific-value biodiesel prepared based on the modified formulation in Examples 1-3 and Comparative Examples 1-3 were tested using the oxygen bomb calorimetry method.

[0030] By comparing and analyzing the relevant data in the table, it can be seen that the biodiesel prepared by this invention has a high cetane number and calorific value. This indicates that the high-calorific-value biodiesel based on the modified formulation provided by this invention has a broader market prospect and is more suitable for promotion.

[0031] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing high-calorific-value biodiesel based on a modified formulation, characterized in that, Includes the following steps: S1: Pretreatment, pretreatment of waste cooking oil to obtain pretreated waste cooking oil; S2: Esterification treatment, which involves esterifying pretreated waste cooking oil. A composite treatment agent is used in the process to obtain a crude product. S3: Refining process, refining the crude product to obtain high-calorific-value biodiesel based on modified formulation; The refining process includes the following steps: A. Separation process: The crude product undergoes separation processing to obtain the preparative material; B. Dehydration and purification treatment: The prepared material is dehydrated and purified to obtain the base material; C. Adsorption treatment: The base material is subjected to adsorption treatment to complete the final refining process and obtain high-calorific-value biodiesel based on the modified formula; The composite treatment agent comprises the following raw materials in parts by weight: 40-60 parts powder, 8-12 parts dopamine hydrochloride, 9.5-14.5 parts epichlorohydrin, and 0.3-0.8 parts initiator.

2. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The pretreatment method for the waste cooking oil is as follows: the recovered waste cooking oil is centrifuged at 3000-4000 rpm for 10-20 min, the solid impurities at the bottom are discarded, and the separated oily substance is mixed with 2-4% anhydrous magnesium sulfate by mass. The mixture is stirred at 150-200 rpm for 30-50 min, then allowed to stand for 20-30 min, and filtered through a 200-mesh filter to obtain the pretreated waste cooking oil, wherein the anhydrous magnesium sulfate has a particle size of 100 μm.

3. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The preparation method of the composite treatment agent is as follows: the powder is dispersed in deionized water at a solid-liquid ratio of 1:20, dopamine hydrochloride is added, and the mixture is stirred at 20-30℃ for 22-26 hours. Then epichlorohydrin is added, the temperature is raised to 55-65℃, and the mixture is stirred for 2.8-3.2 hours. Finally, an initiator and acrylic acid of equal mass to epichlorohydrin are added, the temperature is raised to 65-75℃, and the mixture is stirred for 3.8-4.2 hours. After the reaction, the mixture is transferred to a centrifuge and centrifuged at 3500-4500 rpm for 15-25 minutes. The solid product is collected and washed three times with deionized water at 5 times the mass of the solid product. The final solid product is placed in a vacuum drying oven and vacuum dried at 55-65℃ for 10-14 hours to obtain the composite treatment agent.

4. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The dopamine hydrochloride has a particle size of 150 μm, the epichlorohydrin has a purity of greater than 99%, and the initiator is ammonium persulfate with a particle size of 100 μm.

5. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The powder is prepared as follows: the mixture is added to a 55-60% fuming sulfuric acid aqueous solution at a mass ratio of (8-10):1, and stirred at 100-200 rpm for 2.5-3.5 h at 35-45℃. After the reaction, the product is slowly poured into ice water to quench it. The pH of the system is adjusted to 2-3 with an 8-10% sodium bicarbonate solution. The solid product is collected by filtration, washed with deionized water until neutral, and vacuum dried at 55-65℃ for 8-10 h to obtain the powder.

6. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 5, characterized in that, The preparation method of the mixture is as follows: Konjac glucomannan powder is added to an ethanol aqueous solution with a mass fraction of 5-7% at a mass ratio of 1:(10-15), stirred at 100-150 rpm for 1-1.5 h at 20-30℃, filtered, and dried at 100-110℃ for 3-4 h to obtain refined konjac glucomannan. The refined konjac glucomannan is mixed with chitosan oligosaccharide at a mass ratio of (5-10):1, and a 10% mass concentration sodium hydroxide solution accounting for 8-10% of the mass of the refined konjac glucomannan is added. The mixture is stirred and activated at 70-80℃ for 1.5-2 h, filtered and washed until neutral, and dried at 100-110℃ to constant weight to obtain the mixture, wherein the particle size of the konjac glucomannan is 150 μm.

7. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The esterification treatment method is as follows: a compound treatment agent and methanol are added to the pretreated waste cooking oil, and concentrated sulfuric acid with a mass fraction of 98% is slowly added dropwise. The mixture is stirred at 150-250 rpm for 3.5-4.5 hours at 65-70℃ to obtain a crude product. The mass of the compound treatment agent is 5-8% of the mass of the pretreated waste cooking oil, the volume of methanol is 20-25% of the volume of the pretreated waste cooking oil, and the amount of concentrated sulfuric acid added is 1-2% of the mass of the pretreated waste cooking oil.

8. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The separation process is as follows: the crude product is transferred to a separatory device, washed with hot water at 60-70°C, allowed to stand and separate into layers, the lower aqueous phase is separated and discarded, the resulting oil phase is washed repeatedly until it is neutral, the washed oil phase is allowed to stand and separate into layers for 8-12 hours, the lower glycerol phase is separated and removed, the separation process is completed, and the prepared material is obtained.

9. The method for preparing high-calorific-value biodiesel based on a modified formulation according to claim 1, characterized in that, The dehydration and purification process is as follows: 2% anhydrous sodium sulfate is added to the prepared material, and the mixture is stirred at 200-300 rpm for 20-30 min. After filtration, the filtrate is obtained. The filtrate is then subjected to vacuum distillation at -0.095 MPa and 90°C to complete the dehydration and purification process and obtain the base material. The adsorption treatment method is as follows: the base material is passed through a composite adsorption column containing activated alumina and fine-pore silica gel to complete the adsorption treatment, thereby obtaining high-calorific-value biodiesel based on the modified formula.

10. A high-calorific-value biodiesel based on a modified formulation, characterized in that, It is prepared by the method for preparing high-calorific-value biodiesel based on the modified formulation as described in any one of claims 1-9.

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