A high catalytic efficiency lipase-mediated biodiesel production method

Abstract

This invention discloses a high-efficiency lipase-mediated biodiesel production method, belonging to the field of biodiesel preparation technology, comprising the following steps: S1, using waste animal and vegetable oils as raw materials, filtering and removing impurities, washing with water to remove phospholipids and inorganic acids, adjusting the pH to 5-5.5 to obtain pretreated waste animal and vegetable oils; S2, preparing a slow-release emulsifier, mixing the slow-release emulsifier with the pretreated waste animal and vegetable oils, stirring evenly, then sequentially adding water and liquid lipase lipids, continuing stirring to obtain a homogeneous oil-water interface reaction system; S3, adding methanol in stages at 40°C to the oil-water interface reaction system using a metering pump for reaction, after the reaction is completed, allowing it to settle, discharging the heavy phase to obtain the light phase, heating the light phase to 70-80°C to evaporate the methanol to obtain biodiesel. This invention solves the problem of low enzyme-catalyzed reaction efficiency caused by the instability of the oil-water interface in existing reaction processes.

Description

Technical Field

[0001] This invention belongs to the field of biodiesel preparation and relates to a biodiesel production method mediated by a highly catalytically efficient lipase. Background Technology

[0002] Biodiesel technology is a renewable and clean energy source that produces fatty acid methyl esters through esterification or transesterification reactions of animal and vegetable oils with short-chain alcohols such as methanol. Its products can replace petrochemical diesel. The core processes include alkaline catalysis, acid catalysis, enzymatic methods, and supercritical methods. Among them, enzymatic preparation of biodiesel is an important method for biodiesel production, with advantages such as pure reaction products, environmental protection and energy saving. Eversa Transform 2.0 is a liquid enzyme specifically developed for the biodiesel field. This enzyme has good stability in water, but it can only exhibit biological activity at the oil-water interface. Because enzymatic preparation of biodiesel is time-consuming, the water-oil interface of the reaction system is unstable during the long reaction time, which affects the progress of the enzyme-catalyzed reaction. Moreover, the enzyme activity is affected by methanol, resulting in incomplete liquid enzymatic reaction and low efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a highly efficient lipase-mediated biodiesel production method, which solves the problems of instability at the oil-water interface during the long reaction time in the liquid enzyme catalytic biodiesel production process, and the low efficiency and incomplete enzymatic reaction in liquid enzyme catalysis when methanol inhibits enzyme activity. The technical solution adopted by this invention is as follows: A highly catalytically efficient lipase-mediated biodiesel production method includes the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5-5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring evenly, and then adding water and liquid lipase ester in sequence, and continuing to stir to obtain a uniform oil-water interface reaction system. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. After the reaction was completed, the system was allowed to settle and the heavy phase was removed to obtain the light phase. The light phase was heated to 70-80℃ to evaporate the methanol and obtain biodiesel. The amount of water added is 2-4% of the mass of the pretreated waste animal and vegetable oils; The amount of liquid lipase added is 0.12-0.15% of the mass of the pretreated waste animal and vegetable oils; The amount of methanol added is 33-35% of the mass of the pretreated waste animal and vegetable oils; Furthermore, the liquid lipase is Eversa Transform 2.0 lipase.

[0004] Further, by mass fraction, the sustained-release emulsifier comprises the following components: 30% octenyl succinic anhydride modified starch microspheres, 35% polyglycerol fatty acid ester, 15% sucrose fatty acid ester, 6% xanthan gum, and the balance being deionized water.

[0005] Further, the sustained-release emulsifier is prepared by the following method: polyglycerol fatty acid ester, sucrose fatty acid ester, and deionized water are mixed at 55°C and stirred evenly to obtain a mixed emulsion; while maintaining 55°C, octenyl succinic anhydride modified starch microspheres are added to the mixed emulsion under stirring, and after stirring continuously for 1.5 h, xanthan gum is added, and stirring is continued for 60 min. The mixture is then transferred to a spray dryer, and spray drying is performed with an inlet air temperature of 160°C, an outlet air temperature of 80°C, and a feed rate of 15 mL / min to obtain the sustained-release emulsifier.

[0006] Furthermore, in step S2, the amount of slow-release emulsifier added is 3-5% of the mass of the pretreated waste animal and vegetable oils.

[0007] Further, the octenyl succinic anhydride modified starch microspheres were prepared by the following method: dried corn starch and deionized water were mixed at a mass ratio of 1:4, placed in a constant temperature water bath, heated to 40°C, and stirred until the starch was fully swollen. Then, 0.5% of the corn starch mass of ammonium persulfate was added, and stirring was continued until homogeneous to obtain a starch solution. The mixture of liquid paraffin and Span-80 was heated to 60°C. Under stirring, the starch solution was added dropwise to the mixture of liquid paraffin and Span-80. After the addition was complete, octenyl succinic anhydride was added dropwise, while adjusting the pH of the system to 8.0-8.5. After the addition was complete, 2% of the starch mass of N,N'-methylenebisacrylamide was added, the temperature was raised to 70°C, and the reaction was continued with stirring. After the reaction was complete, the mixture was cooled to room temperature and anhydrous ethanol was added to break the emulsion. The mixture was then allowed to stand and filtered to obtain a filter cake. The filter cake was washed and dried to obtain octenyl succinic anhydride modified starch microspheres.

[0008] Furthermore, the specific steps of step S3 are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 2-3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 14-16 hours; 3.4. Later reaction stage: Maintain 40℃, add the remaining methanol to the oil-water interface reaction system, stir evenly and react for 2-3 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 70-80℃ to evaporate the methanol to obtain biodiesel.

[0009] Furthermore, the amount of octenyl succinic anhydride added is 4% of the mass of corn starch.

[0010] Furthermore, the mass ratio of liquid paraffin to Span-80 is 95:5.

[0011] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention provides a high-catalytic-efficiency lipase-mediated biodiesel production method. By using a slow-release emulsifier, the oil-water interface is kept stable during the reaction process over a long enzymatic reaction period, providing a stable reaction environment for liquid lipase and solving the problem of low enzymatic reaction efficiency caused by unstable oil-water interface in existing reaction processes. 2. The present invention also adjusts the method of adding methanol, thereby reducing the impact of methanol on the enzyme without affecting the reaction efficiency and products. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart of the present invention. Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0013] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0014] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0015] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0016] like Figure 1 As shown, this embodiment of the invention provides a method for producing biodiesel mediated by a highly catalytically efficient lipase, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5-5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring evenly, and then adding water and liquid lipase ester in sequence, and continuing to stir to obtain a uniform oil-water interface reaction system. S3. At 40℃, methanol was added in stages using a metering pump to carry out the reaction in an oil-water interface reaction system. The specific steps are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 2-3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 14-16 hours; 3.4. Later reaction stage: Maintain 40℃, add the remaining methanol to the oil-water interface reaction system, stir evenly and react for 2-3 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 70-80℃ to evaporate the methanol to obtain biodiesel. The amount of water added is 2-4% of the mass of the pretreated waste animal and vegetable oils; The amount of liquid lipase added is 0.12-0.15% of the mass of the pretreated waste animal and vegetable oils; The amount of methanol added is 33-35% of the mass of the pretreated waste animal and vegetable oils; The amount of slow-release emulsifier added is 3-5% of the mass of the pretreated waste animal and vegetable oils; The liquid lipase is Eversa Transform 2.0 lipase.

[0017] In the following examples: the slow-release emulsifier comprises the following components by mass fraction: 30% octenyl succinic anhydride modified starch microspheres, 35% polyglycerol fatty acid esters, 15% sucrose fatty acid esters, 6% xanthan gum, and the balance being deionized water; and the slow-release emulsifier is prepared by the following method: polyglycerol fatty acid esters, sucrose fatty acid esters, and deionized water are mixed at 55°C and stirred evenly to obtain a mixed emulsion; while maintaining 55°C, octenyl succinic anhydride modified starch microspheres are added to the mixed emulsion under stirring, and after stirring continuously for 1.5 hours, xanthan gum is added, and stirring is continued for 60 minutes. The mixture is then transferred to a spray dryer, and the inlet air temperature is set to 160°C, the outlet air temperature to 80°C, and the feed rate to 15 mL / min for spray drying to obtain the slow-release emulsifier.

[0018] In the following examples: the octenyl succinic anhydride modified starch microspheres were prepared by the following method: dried corn starch and deionized water were mixed at a mass ratio of 1:4, placed in a constant temperature water bath, heated to 40°C, and stirred until the starch was fully swollen (stirring rate 150 r / min, stirring for 30 min). Then, 0.5% (by mass) of ammonium persulfate was added to the corn starch mixture, and stirring was continued until homogeneous to obtain a starch solution. A mixture of liquid paraffin and Span-80 at a mass ratio of 95:5 was heated to 60°C and stirred (stirring...) At a rate of 300 r / min, starch solution was added dropwise to a mixture of liquid paraffin and Span-80. After the addition was complete, 4% (by weight of corn starch) of octenyl succinic anhydride was added dropwise, while adjusting the pH of the system to 8.5. After the addition was complete, 2% (by weight of starch) of N,N'-methylenebisacrylamide was added, the temperature was raised to 70°C, and the reaction was continued with stirring (6 h). After the reaction was complete, the mixture was cooled to room temperature and anhydrous ethanol was added to break the emulsion. The mixture was then allowed to stand and filtered to obtain a filter cake. The filter cake was washed and dried to obtain octenyl succinic anhydride modified starch microspheres.

[0019] Example 1 This embodiment provides a highly catalytically efficient lipase-mediated biodiesel production method, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with the pretreated waste animal and vegetable oils, stirring until homogeneous, and then sequentially adding water and liquid lipase lipoprotein (Eversa Transform 2.0 lipase), continuing stirring to obtain a homogeneous oil-water interface reaction system. The amount of water added is 2% of the mass of the pretreated waste animal and vegetable oils; the amount of liquid lipase lipoprotein added is 0.12% of the mass of the pretreated waste animal and vegetable oils; and the amount of slow-release emulsifier added is 3% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. The amount of methanol added was 33% of the mass of the pretreated waste animal and vegetable oils. The specific steps are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 2 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 14 hours; 3.4. Later reaction stage: Maintain 40℃, add the remaining methanol to the oil-water interface reaction system, stir evenly and react for 2 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 80℃ to evaporate the methanol to obtain biodiesel.

[0020] Example 2 This embodiment provides a highly catalytically efficient lipase-mediated biodiesel production method, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring until homogeneous, and then sequentially adding water and liquid lipase lipoprotein (Eversa Transform 2.0 lipase), continuing stirring to obtain a homogeneous oil-water interface reaction system. The amount of water added is 3% of the mass of the pretreated waste animal and vegetable oils; the amount of liquid lipase lipoprotein added is 0.13% of the mass of the pretreated waste animal and vegetable oils; and the amount of slow-release emulsifier added is 4% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. The amount of methanol added was 34% of the mass of the pretreated waste animal and vegetable oils. The specific steps are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 15 hours; 3.4. Later reaction stage: Maintain 40℃, add methanol to the oil-water interface reaction system, stir evenly and react for 2 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 80℃ to evaporate the methanol to obtain biodiesel.

[0021] Example 3 Based on Example 1, this preferred embodiment of the present invention provides a method for producing biodiesel using a highly catalytically efficient lipase-mediated process, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring until homogeneous, and then sequentially adding water and liquid lipase lipoprotein (Eversa Transform 2.0 lipase), continuing stirring to obtain a homogeneous oil-water interface reaction system. The amount of water added is 4% of the mass of the pretreated waste animal and vegetable oils; the amount of liquid lipase lipoprotein added is 0.15% of the mass of the pretreated waste animal and vegetable oils; and the amount of slow-release emulsifier added is 5% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. The amount of methanol added was 35% of the mass of the pretreated waste animal and vegetable oils. The specific steps are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 16 hours; 3.4. Later reaction stage: Maintain 40℃, add methanol to the oil-water interface reaction system, stir evenly and react for 3 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 80℃ to evaporate the methanol to obtain biodiesel.

[0022] Comparative Example 1 This comparative example provides a highly catalytically efficient lipase-mediated biodiesel production method, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Water and liquid lipase (Eversa Transform 2.0) are added sequentially to the waste animal and vegetable oils, and stirring is continued to obtain a homogeneous oil-water interface reaction system; wherein, the amount of water added is 3% of the mass of the pretreated waste animal and vegetable oils; wherein, the amount of liquid lipase added is 0.13% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added to the oil-water interface reaction system at 40℃ for 20 hours. After the reaction was completed, the system was allowed to settle and the heavy phase was removed to obtain the light phase. The light phase was heated to 80℃ to evaporate the methanol and obtain biodiesel. The amount of methanol added was 34% of the mass of the pretreated waste animal and vegetable oils.

[0023] Comparative Example 2 Based on Example 2, but unlike Example 2, this comparative example does not include a slow-release emulsifier. It provides a highly catalytically efficient lipase-mediated biodiesel production method, comprising the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Water and liquid lipase lipase (EversaTransform 2.0) are added sequentially to the pretreated waste animal and vegetable oils, and stirring is continued to obtain a homogeneous oil-water interface reaction system; wherein the amount of water added is 3% of the mass of the pretreated waste animal and vegetable oils; wherein the amount of liquid lipase lipase added is 0.13% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. The amount of methanol added was 34% of the mass of the pretreated waste animal and vegetable oils. The specific steps are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 15 hours; 3.4. Later reaction stage: Maintain 40℃, add methanol to the oil-water interface reaction system, stir evenly and react for 2 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 80℃ to evaporate the methanol to obtain biodiesel.

[0024] Comparative Example 3 Based on Example 2, but unlike Example 2, this comparative example does not use a segmented addition method when adding methanol, but uses a one-time addition method. This comparative example provides a high-catalytic-efficiency lipase-mediated biodiesel production method, which includes the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring until homogeneous, and then sequentially adding water and liquid lipase lipoprotein (Eversa Transform 2.0 lipase), continuing stirring to obtain a homogeneous oil-water interface reaction system. The amount of water added is 3% of the mass of the pretreated waste animal and vegetable oils; the amount of liquid lipase lipoprotein added is 0.13% of the mass of the pretreated waste animal and vegetable oils; and the amount of slow-release emulsifier added is 4% of the mass of the pretreated waste animal and vegetable oils. S3. Methanol was added to the oil-water interface reaction system at 40℃ for 20 hours. After the reaction was completed, the system was allowed to settle and the heavy phase was removed to obtain the light phase. The light phase was heated to 80℃ to evaporate the methanol and obtain biodiesel. The amount of methanol added was 34% of the mass of the pretreated waste animal and vegetable oils.

[0025] Comparative Example 4 Based on Example 2, the difference from Example 2 is that the emulsifier in this comparative example is not a slow-release emulsifier. The added emulsifier is a polyglycerol fatty acid ester and sucrose fatty acid ester complex with a mass ratio of 7:3. The amount added is the same as in Example 2, and the rest are the same.

[0026] Comparative Example 5 Based on Example 2, the difference from Example 2 is that the slow-release emulsifier in this comparative example includes the following components: 30% starch microspheres, 35% polyglycerol fatty acid esters, 15% sucrose fatty acid esters, 6% xanthan gum, and the balance being deionized water. The preparation method is the same as in Example 2, wherein the starch microspheres are corn starch microspheres; the remaining parts are the same as in Example 2.

[0027] Experimental Example 1 According to standard GB / T 20828-2015, the total glycerol content (mass fraction), acid value (calculated as KOH, mg / g), and ester content (mass fraction) in the biodiesel prepared in Examples 1-3 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0028] Table 1. Partial performance test results of biodiesel According to standard GB / T 20828-2015, the acid value should not exceed 0.50 mg KOH / g. The acid value reflects the content of acidic substances in biodiesel. Excessive acidity can corrode engine fuel system components such as fuel pumps, injectors, and fuel lines, shortening equipment lifespan. It may also lead to poor oxidation stability of biodiesel, generating gum and sludge, affecting combustion efficiency, and causing a decline in engine performance. The acid value in this application is far below 0.50 mg KOH / g. According to the results of liquid enzymatic reactions, the lower the total glycerol content, the more complete the transesterification reaction. Generally, a total glycerol content of <1% indicates that the transesterification reaction is essentially complete. The preparation method in this application results in a complete reaction and yields biodiesel with a low acid value.

[0029] Experimental Example 2 The appearance characteristics, kinematic viscosity at 40°C, density at 15°C, flash point, cetane number, and sulfur content of the biodiesel obtained in Examples 1-3 were tested in accordance with the standards specified in GB / T 20828-2015. The appearance characteristics can be directly observed, and the results are shown in Table 2.

[0030] Density determination was performed according to GB / T 1884 "Laboratory Determination of Density of Crude Oil and Liquid Petroleum Products (Density Meter Method)"; kinematic viscosity determination was performed according to GB / T 265 "Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity of Petroleum Products"; flash point (closed cup) determination was performed according to GB / T 261 "Determination of Flash Point - Binsky-Martin Closed Cup Method"; cetane number determination was performed according to GB / T 386 "Determination of Cetane Number of Diesel Oil"; sulfur content determination may be performed according to SH / T 0689 "Determination of Total Sulfur Content of Light Hydrocarbons, Engine Fuels and Other Oils (Ultraviolet Fluorescence Method)".

[0031] Table 2. Partial performance test results of biodiesel Based on the data in Tables 1 and 2, it can be seen that this application can obtain high-quality biodiesel, and the preparation method of this application has high catalytic efficiency and complete reaction.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high catalytic efficiency lipase-mediated biodiesel production method, characterized by: Includes the following steps: S1. Using waste animal and vegetable oils as raw materials, the raw materials are filtered to remove impurities, washed with water to remove phospholipids and inorganic acids, and the pH is adjusted to 5-5.5 to obtain pretreated waste animal and vegetable oils. S2. Prepare a slow-release emulsifier by mixing the slow-release emulsifier with pretreated waste animal and vegetable oils, stirring evenly, and then adding water and liquid lipase in sequence, and continuing to stir to obtain a uniform oil-water interface reaction system. S3. Methanol was added in stages using a metering pump in an oil-water interface reaction system at 40℃. After the reaction was completed, the system was allowed to settle and the heavy phase was removed to obtain the light phase. The light phase was heated to 70℃-80℃ to evaporate methanol and obtain biodiesel. The amount of water added is 2%-4% of the mass of the pretreated waste animal and vegetable oils; The amount of liquid lipase added is 0.12%-0.15% of the mass of the pretreated waste animal and vegetable oils; The amount of methanol added is 33%-35% of the mass of the pretreated waste animal and vegetable oils; The liquid lipase is Eversa Transform 2.0 lipase; The sustained-release emulsifier comprises the following components by mass fraction: 30% octenyl succinic anhydride modified starch microspheres, 35% polyglycerol fatty acid ester, 15% sucrose fatty acid ester, 6% xanthan gum, and the balance being deionized water. The sustained-release emulsifier was prepared by the following method: polyglycerol fatty acid ester, sucrose fatty acid ester, and deionized water were mixed at 55°C and stirred until homogeneous to obtain a mixed emulsion; while maintaining 55°C, octenyl succinic anhydride modified starch microspheres were added to the mixed emulsion under stirring, and after stirring for 1.5 h, xanthan gum was added, and stirring was continued for 60 min. The mixture was then transferred to a spray dryer, and spray drying was performed with an inlet air temperature of 160°C, an outlet air temperature of 80°C, and a feed rate of 15 mL / min to obtain the sustained-release emulsifier. In step S2, the amount of slow-release emulsifier added is 3%-5% of the mass of the pretreated waste animal and vegetable oils; The octenyl succinic anhydride modified starch microspheres were prepared by the following method: Dry corn starch and deionized water were mixed at a mass ratio of 1:4 and placed in a constant temperature water bath. The mixture was heated to 40°C and stirred until the starch was fully swollen. Then, 0.5% (by weight of corn starch) of ammonium persulfate was added, and the mixture was stirred until homogeneous to obtain a starch solution. A mixture of liquid paraffin and Span-80 was heated to 60°C. Under stirring, the starch solution was added dropwise to the mixture. After the addition was complete, octenyl succinic anhydride was added dropwise while adjusting the pH of the system to 8.0-8.

5. After the addition was complete, 2% (by weight of starch) of N,N'-methylenebisacrylamide was added. The mixture was heated to 70°C and stirred continuously. After the reaction was complete, the mixture was cooled to room temperature and anhydrous ethanol was added to break the emulsion. The mixture was then allowed to stand and filtered to obtain a filter cake. The filter cake was washed and dried to obtain octenyl succinic anhydride modified starch microspheres. The specific steps of step S3 are as follows: S3.1 Initial reaction stage: Add 10% of the total amount of methanol to the oil-water interface reaction system at 40℃, stir evenly, and react for 2-3 hours; S3.2, Mid-reaction stage: Maintain 40℃, add 18% of the total amount of methanol to the oil-water interface reaction system, stir evenly and react for 14-16 hours; S3.3, Later reaction stage: Maintain 40℃, add the remaining methanol to the oil-water interface reaction system, stir evenly and react for 2-3 hours. After the reaction is completed, let it stand and settle, remove the heavy phase and obtain the light phase. Heat the light phase to 70-80℃ to evaporate the methanol to obtain biodiesel.

2. The method of claim 1, wherein the catalytic efficiency of the lipase is high. The amount of octenyl succinic anhydride added is 4% of the mass of corn starch.

3. The method of claim 1, wherein the catalytic efficiency is high. The mass ratio of liquid paraffin to Span-80 is 95:5.

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