CN114015511A - Preparation method of biodiesel - Google Patents

Preparation method of biodiesel Download PDF

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Publication number
CN114015511A
CN114015511A CN202111346478.6A CN202111346478A CN114015511A CN 114015511 A CN114015511 A CN 114015511A CN 202111346478 A CN202111346478 A CN 202111346478A CN 114015511 A CN114015511 A CN 114015511A
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reaction
biodiesel
section
palm oil
venturi ejector
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梅华
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Jiangsu Nuo Meng Hydrogen Energy Technology Co ltd
Nanjing Tech University
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Jiangsu Nuo Meng Hydrogen Energy Technology Co ltd
Nanjing Tech University
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    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
    • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
    • C11C3/04—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fats or fatty oils
    • C11C3/10—Ester interchange
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/04—Pressure vessels, e.g. autoclaves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/0005—Catalytic processes under superatmospheric pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/08—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with moving particles
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L1/00—Liquid carbonaceous fuels
    • C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
    • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
    • C11C3/04—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fats or fatty oils
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/10—Biofuels, e.g. bio-diesel

Abstract

The invention discloses a preparation method of biodiesel, which takes methanol and palm oil as raw materials, takes solid alkali as a catalyst, adopts a jet loop reactor as a reactor, and introduces nitrogen into the jet loop reactor in the reaction process to maintain the reaction pressure, so as to prepare the biodiesel; the molar ratio of the methanol to the palm oil is (2-13): 1, adding the catalyst in an amount of 1-4% of the mass of the palm oil; the reaction temperature is 60-110 ℃, the reaction pressure is 0.4-1.5 Mpa, and the reaction time is 20-60 min. The invention adopts the jet loop reactor, takes the solid alkali as the catalyst and takes the methanol and the palm oil as the raw materials, fully utilizes the strong mass transfer effect of the Venturi jet reactor, effectively shortens the reaction time and improves the yield.

Description

Preparation method of biodiesel
Technical Field
The invention belongs to the technical field of chemical production, and particularly relates to a process method for producing biodiesel by adopting novel reactor equipment, namely a loop reactor.
Background
The biodiesel is a fatty acid methyl ester substance which is obtained by taking vegetable oil or animal fat as a main raw material through ester exchange reaction, is used as a green renewable resource, and becomes an ideal substitute of petroleum diesel by the unique property of the biodiesel.
In the preparation process of biodiesel (fatty acid methyl ester), the reaction rate is very low because triglyceride fatty acid and methanol are not well miscible. When a traditional stirred tank is used as a reactor, miscible ethers are usually added to form a homogeneous reaction system so as to accelerate the reaction rate, and most of the used catalysts are homogeneous base catalysts or acid catalysts, so that the process conditions have the problems of complex process, poor reproducibility, difficult separation and purification of products, complicated post-treatment, large discharge capacity, easy generation of three wastes and the like, and the application of the process is greatly limited.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provide a biodiesel production process which has high production efficiency and is easy to separate and purify products.
In order to achieve the aim, the invention provides a preparation method of biodiesel, which takes methanol and palm oil as raw materials, takes solid alkali as a catalyst, adopts a jet loop reactor as a reactor, and introduces nitrogen into the jet loop reactor in the reaction process to maintain the reaction pressure so as to prepare the biodiesel; the molar ratio of the methanol to the palm oil is (2-13): 1, adding a catalyst in an amount of 1.5-4% of the mass of the palm oil; the reaction temperature is 60-110 ℃, the reaction pressure is 0.5-1.5Mpa, and the reaction time is 20-60 min.
The jet loop reactor is a novel reactor system, reaction fluid circulates in a loop at a large flow rate, is jetted at a high speed through a Venturi ejector (mixer), and forms negative pressure at a working nozzle, so that process gas is sucked into the ejector to form micron-sized bubbles with large specific surface area, the gas-liquid contact is increased, and the gas-liquid (or gas-liquid-solid) multiphase reaction speed can be accelerated.
The invention utilizes the action of air bubbles in the injection loop reactor to cut and shear liquid in an injection mixing area (a mixing section and a diffusion section of a Venturi ejector) and liquid in a reaction kettle, promotes the diffusion mass transfer between the liquids, and plays a role of strongly stirring a heterogeneous system formed by methanol-triglyceride-solid base catalyst-nitrogen for preparing biodiesel, thereby accelerating the chemical reaction speed. The invention obtains the process conditions more suitable for the preparation of the biodiesel by groping the production process parameters, and further improves the production efficiency.
Meanwhile, solid alkali is used as a catalyst to replace a homogeneous alkali catalyst in the traditional process, and the product is easy to separate and recycle after the reaction is finished.
Further, the jet loop reactor comprises a reaction kettle, a circulating pump, a heat exchanger and a Venturi ejector; the materials in the reaction kettle sequentially pass through the circulating pump, the heat exchanger and the Venturi ejector and then circularly enter the reaction kettle; the Venturi ejector comprises an inlet section, a nozzle, a mixing section and a diffusion section which are communicated in sequence, wherein the inlet section and the nozzle are in a tapered tubular shape, tapered annular air chambers are arranged on the peripheries of the inlet section and the nozzle, and the air chambers are communicated with the mixing section; the gas chamber is communicated with a gas inlet arranged at the upper part of the reaction kettle through a gas circulating pipe; the diffusion section is in a gradually expanding tubular shape; the specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38: (1.5-4): (2-6): (90-190): (800-1600), the opening angle of the diffuser section is 8-20 degrees.
According to the invention, the specification and the size of the Venturi ejector are improved and designed, so that the Venturi ejector is more suitable for the preparation of the biodiesel, the reaction rate is further improved, and higher equipment productivity is obtained.
In some embodiments, it is preferable that the linear velocity of the fluid at the nozzle of the Venturi ejector is controlled to be 90-130 m/s during the reaction process.
In some embodiments, the solid base is preferably KF/MgO, KF/CaO, KF/Al2O3Or K2CO3/Al2O3(ii) a The KF/MgO takes MgO as a carrier, and KF with the MgO mass of 60% is loaded on the KF/MgO; the KF/CaO takes CaO as a carrier, and 14 percent of the CaO is loaded on the carrierKF; the KF/Al2O3With Al2O3As a carrier, Al is loaded thereon2O315% by mass of KF; said K2CO3/Al2O3With Al2O3As a carrier, Al is loaded thereon2O320% by mass of K2CO3. More preferably, the solid base is K2CO3/Al2O3。
In some embodiments, it is more preferred that the molar ratio of methanol to palm oil is 8:1, adding the catalyst in an amount of 2% of the mass of the palm oil; in the reaction process, the reaction temperature is controlled to be 85 ℃, the reaction pressure is 0.9MPa, and the linear velocity of the fluid at the nozzle of the Venturi ejector is 115 m/s.
The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:3:4: 140: 1200, the opening angle of the diffuser section is 14 °.
Compared with the prior art, the invention has the following advantages:
1. the invention adopts the jet loop reactor, takes the solid alkali as the catalyst and takes the methanol and the palm oil as the raw materials, fully utilizes the strong mass transfer effect of the Venturi jet reactor, effectively shortens the reaction time and improves the yield.
2. The solid base catalyst is adopted to replace a homogeneous base catalyst, so that the method has the advantages of easiness in separation from the product, easiness in regeneration of the catalyst after reaction, low corrosion to equipment and the like, the finally obtained product biodiesel is easy to separate and purify, and the catalyst can be recycled.
Drawings
FIG. 1 is a schematic diagram of the configuration of a jet loop reactor for biodiesel production;
FIG. 2 is a schematic structural view of the venturi ejector of FIG. 1;
FIG. 3 is a graph showing the number of times of repeated use of the solid base of the present invention as a catalyst and the actual yield of biodiesel.
In the figure, 1-reaction kettle, 2-Venturi ejector, 3-heat exchanger, 4-circulating pump, 5-gas circulating pipe, 6-inlet section, 7-mixing section, 8-diffusion section, 9-nozzle and 10-gas chamber.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
First, catalyst preparation
The reagents used were:
KF·2H2o (national chemical group chemicals, ltd A.R.);
K2CO3(national pharmaceutical group chemical agents, ltd A.R.);
MgO powder SBET＝186m2(ii)/g (national drug group chemical Co., Ltd A.R);
CaO (national chemical group, chemical Co., Ltd A.R);
the alumina carrier is from Jinling petrochemical alkylbenzene factory, has a diameter of 1-2mm, and is ground into powder for use, SBET＝211m2/g。
KF/Al2O3The preparation process comprises the following steps: grinding a certain amount of aluminum oxide into powder, sieving out 100-mesh and 200-mesh powder, and adding KF & 2H2And O (wherein the mass of KF is 15 percent of the mass of the alumina powder), adding a proper amount of distilled water, uniformly stirring, standing for 10 hours, drying at 60 ℃ for 24 hours, heating to 550 ℃ at the speed of 5 ℃/min, keeping the temperature for 6 hours, taking out, and cooling in a dryer for later use.
K2CO3/Al2O3The preparation process comprises the following steps: grinding a certain amount of alumina into powder, sieving out powder of 100 meshes and 200 meshes, adding K accounting for 20 percent of the mass of the alumina powder2CO3Adding appropriate amount of distilled water, stirring, standing for 10h, drying at 60 deg.C for 24h, heating to 600 deg.C at 5 deg.C/min, keeping the temperature for 5h, taking out, and cooling in a drier.
KF/MgO preparation process: weighing a certain amount of KF.2H by an isovolumetric immersion method2Dissolving O in a proper amount of deionized water, adding MgO powder as a carrier, allowing the mass of KF to be 60% of the mass of MgO, stirring and evaporating in a water bath at 80 ℃, heating to 550 ℃ at 5 ℃/min, keeping the temperature for 4h, taking out, and cooling in a dryer for later use.
KF/CaO preparation toolThe method comprises the following steps: weighing a certain amount of KF.2H by an isovolumetric immersion method2Dissolving O in a proper amount of deionized water, adding CgO powder of a carrier to ensure that the mass of KF accounts for 14% of the mass of CaO, stirring and evaporating in a water bath at 80 ℃, heating to 550 ℃ at the speed of 5 ℃/min, keeping the temperature for 4h, taking out and cooling in a dryer for later use.
Second, injection loop reactor for preparing biodiesel
As shown in fig. 1, the biodiesel production of the present invention was carried out using an injection loop reactor. The loop reactor comprises a reaction kettle 1, a Venturi ejector 2, a heat exchanger 3 and a circulating pump 4.
When the equipment works, the circulating pump 4 is started. The reaction fluid circulates in the loop at a high flow rate, the venturi ejector 2 ejects at high speed, creating a negative pressure at the working nozzle, so that the gas (process gas nitrogen) is sucked into the venturi ejector. One side of the top of the reaction kettle 1 is provided with a gas circulation pipe 5 which is connected with a gas inlet and can form gas circuit circulation locally. The small bubbles with large specific surface area are formed in the Venturi ejector, and the mass transfer process between gas-liquid-solid heterogeneous reaction materials is enhanced and the reaction time is shortened by dividing and stirring liquid flow. The lower end of the Venturi ejector is positioned below the liquid level, and the gas-liquid-solid mixed material and the materials in the reaction kettle are impacted, so that the effect of promoting dispersion and mixing is achieved, and the reaction is promoted to further proceed. The material enters a heat exchanger 4 from the bottom end of the reaction kettle through a circulating pump 3 and then enters a Venturi ejector 2 from the top end of the reaction kettle 1. The heat exchanger 4 removes or supplies heat released or absorbed during the reaction and controls the reaction temperature to fluctuate by + -1 deg.C. In the reaction process, a pressure regulating device is adopted to control and maintain a certain pressure of the reaction system.
The heat exchanger in the patent can adopt a tubular heat exchanger or a plate heat exchanger.
With reference to fig. 2, the venturi ejector of the present patent is composed in particular of an inlet section 6 in the shape of a convergent tube, a mixing section 7, a diffuser section 8, a nozzle 9 and a gas chamber 10. As shown in FIG. 1, the side of the gas chamber 1 is connected to the top gas inlet of the reaction vessel 1 through a gas circulation pipe 5 to provide a gas circulation space of a local region.
Example 1
Example of screening reaction raw material ratio
Refluxing anhydrous methanol and sodium hydroxide to remove acid, processing to obtain palm oil and KF/Al2O3Adding the catalyst into a reaction kettle (5L); introducing nitrogen into the reaction system through the air inlet 16 until the system pressure is 1MPa, starting the circulating pump 4 to enable the fluid in the kettle to slowly flow, emptying, and repeatedly replacing the air in the injection loop reactor for 6 times. After the last replacement, keeping a certain pressure of the reaction system, immediately supplementing nitrogen to the reaction pressure after heating to the reaction temperature (the heating time is about 10min), and adjusting the flow rate from the circulating pump 4 to the nozzle of the Venturi ejector to a certain value, and recording the flow rate as the reaction starting time.
When the reaction is finished, the flow rate of the circulating pump 4 is immediately reduced and the temperature is rapidly reduced to the room temperature (the temperature reduction time is about 10 min). And (5) exhausting the gas in the reaction kettle and discharging the product in the reaction kettle. And taking part of the product, centrifuging and layering, taking the upper layer, and performing vacuum rectification and purification to calculate the actual yield according to the quality of the biodiesel obtained by final rectification and the quality of palm oil in the reaction raw material.
In the example, the actual yield of biodiesel was compared by changing the addition ratio of methanol to palm oil. The other production process parameters are as follows: the using amount of the catalyst is 2% of the palm oil by mass, the reaction pressure is 0.9MPa, the reaction temperature is 65 ℃, the reaction time is 40min, and the specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:2:3:150:1000, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, carrying out reduced pressure rectification to obtain yellow transparent liquid biodiesel, and calculating the yield of the biodiesel according to the proportion of the obtained product.
The actual yields obtained for the different feed addition ratios are shown in table 1 below.
TABLE 1 screening of the methanol/palm oil ratio (alcohol-to-oil ratio)
Figure BDA0003354178480000051
As can be seen from the table above, the actual yield gradually increases with the increase of the alcohol-oil ratio, but when the alcohol-oil ratio is higher than 8:1, the yield decreases; and when the alcohol-oil ratio is too small (2:1) or too large (13:1), the actual yield is greatly reduced, so that the alcohol-oil molar ratio is controlled to be (3-12): 1 to obtain better yield, and the optimal alcohol-oil ratio is 8: 1.
Example 2
Example of screening reaction temperature
The preparation method of biodiesel is the same as that of example 1.
In this example, the reaction temperature was varied to compare the actual yield of biodiesel. The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), the dosage of the catalyst is 2% of the mass of the palm oil, the reaction pressure is 0.9MPa, the reaction time is 40min, and the specification and the size of a Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:2:3:150:1000, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, carrying out reduced pressure rectification to obtain yellow transparent liquid biodiesel, and calculating the yield of the biodiesel according to the proportion of the obtained product.
The actual yields obtained for the different reaction temperatures are shown in table 2 below.
TABLE 2 screening results of reaction temperature
Reaction temperature C Actual yield%
50 56.6
65 82.7
75 84.2
85 88.6
95 83.1
105 79.4
120 70.5
As can be seen from the above table, the actual yield gradually increased as the reaction temperature increased, but the yield continued to decrease as the reaction temperature increased above 85 ℃. Meanwhile, when the reaction temperature is too high (120 ℃) or too low (50 ℃), the yield is obviously reduced. It is therefore preferred to control the temperature between 60-110 ℃ and the optimum reaction temperature is 85 ℃.
Example 3
Example of reaction pressure screening
The preparation method of biodiesel is the same as that of example 1.
In this example, the reaction pressure was varied and the actual yield of biodiesel was compared. The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), the dosage of the catalyst is 2% of the mass of the palm oil, the reaction temperature is 85 ℃, the reaction time is 40min, and the specification and the size of a Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:2:3:150:1000, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, carrying out reduced pressure rectification to obtain yellow transparent liquid biodiesel, and calculating the yield of the biodiesel according to the proportion of the obtained product.
The actual yields obtained for the different reaction pressures are shown in table 3 below.
TABLE 3 screening results of reaction pressure
Reaction pressure MPa Actual yield%
0.3 72.8
0.5 78.6
0.7 83.5
0.9 88.6
1.2 87.4
1.4 82.3
1.6 76.5
As can be seen from the above table, with the increase of the reaction pressure, the actual yield also gradually increased, but when the reaction pressure is greater than 0.9Mpa, the yield continuously decreased; and when the reaction pressure is too high (1.6MPa) or too low (0.3MPa), the yield is remarkably reduced. Therefore, it is preferable to control the pressure to 0.5 to 1.5MPa, and the optimum reaction pressure is 0.9 MPa.
Example 4
Example of catalyst dosage selection
The preparation method of biodiesel is the same as that of example 1.
In this example, the amount of catalyst was varied to compare the actual yield of biodiesel. The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), the reaction temperature is 85 ℃, the reaction time is 40min, and the specification and the size of a Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:2:3:150:1000, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, carrying out reduced pressure rectification to obtain yellow transparent liquid biodiesel, and calculating the yield of the biodiesel according to the proportion of the obtained product.
The actual yields obtained with different catalyst amounts are shown in table 4 below.
TABLE 4 screening results of catalyst amounts
Figure BDA0003354178480000081
As can be seen from the above table, in order to obtain better yield, the amount of the catalyst should be controlled between 1.5% and 4%, and the optimal amount of the catalyst is 2% of the palm oil by mass.
Example 5
Example of reaction time screening
The preparation method of biodiesel is the same as that of example 1.
In this example, the reaction time was varied and the actual yield of biodiesel was compared. The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), the dosage of the catalyst is 2 percent of the mass of the palm oil, the reaction temperature is 85 ℃, the reaction pressure is 0.9MPa, and the specification and the size of a Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:2:3:150:1000, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, carrying out reduced pressure rectification to obtain yellow transparent liquid biodiesel, and calculating the yield of the biodiesel according to the proportion of the obtained product.
The actual yields obtained for the different reaction times are shown in table 5 below.
TABLE 5 screening results of reaction time
Reaction time min Actual yield%
10 61.6
20 75.4
40 88.6
60 86.9
80 84.8
As can be seen from the above table, better yield can be obtained by controlling the reaction time to be between 20 and 80min, and the optimal reaction time is 40 min.
Example 6
The preparation method of biodiesel is the same as that of example 1.
This implementationIn the examples, the molar ratio of methanol to palm oil was 3:1 (methanol pre-feeding amount is 290g, palm oil pre-feeding amount is 2700g), KF/Al is adopted as the catalyst2O3The pre-feeding amount is 2 percent (54g) of the palm oil mass, the reaction pressure is 0.8MPa, the reaction temperature is 70 ℃, and the reaction time is 55 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:2.5:3.5:140:1300, the opening angle of the diffuser section is 15 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 110 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 91.5% according to the proportion of the obtained product.
Example 7
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 5:1 (methanol pre-feeding amount is 480g, palm oil pre-feeding amount is 2700g), KF/Al is adopted as the catalyst2O3, the pre-feeding amount is 1.5 percent (40.5g) of the mass of the palm oil, the reaction pressure is 0.6MPa, the reaction temperature is 65 ℃, and the reaction time is 50 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:2:3:150:1000, the opening angle of the diffuser section is 11 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 125 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 90.4% according to the proportion of the obtained product.
Example 8
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 8:1 (the methanol pre-feeding amount is 770g, the palm oil pre-feeding amount is 2700g), and the catalyst adopts K2CO3/Al2O3The pre-feeding amount is 2 percent (54g) of the palm oil mass, the reaction pressure is 0.9MPa, the reaction temperature is 85 ℃, and the reaction time is 40 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: inner diameter of nozzle: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:3:4: 140: 1200, the opening angle of the diffuser section is 14 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in reaction is 115 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 98.6 percent according to the proportion of the obtained product.
Example 9
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 6: 1 (the methanol pre-feeding amount is 580g, the palm oil pre-feeding amount is 2700g), KF/MgO is adopted as a catalyst, the pre-feeding amount is 2.5 percent (67.5g) of the mass of the palm oil, the reaction pressure is 1MPa, the reaction temperature is 75 ℃, and the reaction time is 45 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:3:4:170:1400, the opening angle of the diffuser section is 18 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 105 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 95.5 percent according to the proportion of the obtained product.
Example 10
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 8:1 (the methanol pre-feeding amount is 770g, the palm oil pre-feeding amount is 2700g), KF/CaO is adopted as a catalyst, the pre-feeding amount is 3 percent (81g) of the mass of the palm oil, the reaction pressure is 1.1MPa, the reaction temperature is 90 ℃, and the reaction time is 35 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffusion section is 38:3.5:5:160:1500, the opening angle of the diffusion section is 15 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 120 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 92.1% according to the proportion of the obtained product.
Example 11
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 10: 1 (methanol pre-feeding amount is 853g, palm oil pre-feeding amount is 2400g), and K is adopted as a catalyst2CO3/Al2O3The pre-feeding amount is 3.5 percent (84g) of the palm oil mass, the reaction pressure is 1.2MPa, the reaction temperature is 95 ℃, and the reaction time is 30 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:3:4:105:1100, the opening angle of the diffuser section is 10 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 123 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 89.8 percent according to the proportion of the obtained product.
Example 12
The preparation method of biodiesel is the same as that of example 1.
In this example, the molar ratio of methanol to palm oil was 12: 1 (methanol pre-feeding amount is 1024g, palm oil pre-feeding amount is 2400g), and the catalyst adopts KF/Al2O3The pre-feeding amount is 2.8 percent (67.2g) of the mass of the palm oil, the reaction pressure is 1.4MPa, the reaction temperature is 100 ℃, and the reaction time is 25 min. The specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:2:3.5:180:1150, the opening angle of the diffuser section is 12 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 128 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 90.2% according to the proportion of the obtained product.
Example 13
The product obtained after the reaction in example 8 was centrifuged, filtered, washed with methanol, and calcined at 600 ℃ for 2 hours to obtain a catalyst powder. Repeatedly used for preparing the biodiesel. The graph of the repeated use times and the actual yield of the biodiesel in the obtained product is shown in figure 3.
As can be seen from FIG. 3, the recovered and regenerated catalyst still maintains good activity, and higher biodiesel yield is obtained.
Comparative example 1
The preparation method of biodiesel is the same as that of example 1.
The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), and K is adopted as a catalyst2CO3/Al2O3The using amount of the catalyst is 2% of the mass of the palm oil, the reaction temperature is 85 ℃, the reaction pressure is 0.9MPa, the reaction time is 40min, and the specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:2:3:150:750, the opening angle of the diffuser section is 22 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain the yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 65.5 percent according to the proportion of the obtained product.
Comparative example 2
The preparation method of biodiesel is the same as that of example 1.
The other production process parameters are as follows: the alcohol-oil ratio is 8:1 (770 g of methanol and 2700g of palm oil), and the catalyst adopts KF/Al2O3The using amount of the catalyst is 2% of the mass of the palm oil, the reaction temperature is 85 ℃, the reaction pressure is 0.9MPa, the reaction time is 40min, and the specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: the length of the diffuser section is 38:3.5:5:160:1700, the opening angle of the diffuser section is 25 degrees, and the linear velocity of the fluid at the nozzle of the Venturi ejector in the reaction is 95 m/s. Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 70.4% according to the proportion of the obtained product.
Comparative example 3
1200g of deacidified palm oil and 340g of anhydrous methanol, KF/Al were sequentially added to a 2L autoclave2O354g of catalyst powder, charging nitrogen gas under 1MPa, replacing for 3 times, starting stirring and heating, adjusting the rotating speed to 750 r/min, heating to 85 ℃, and passing throughThe pressure regulator maintained the reaction pressure at 1MPa, which is recorded as the start of the reaction, and the reaction time at 5 h.
Taking the mixture after the reaction, centrifuging, layering, and carrying out vacuum rectification to obtain yellow transparent liquid biodiesel, wherein the yield of the biodiesel is 35.2% according to the proportion of the obtained product.

Claims (7)

1. The preparation method of the biodiesel is characterized in that the preparation method takes methanol and palm oil as raw materials, takes solid alkali as a catalyst, adopts a jet loop reactor as a reactor, and introduces nitrogen into the jet loop reactor in the reaction process to maintain the reaction pressure to prepare the biodiesel; the molar ratio of the methanol to the palm oil is (2-13): 1, adding a catalyst in an amount of 1.5-4% of the mass of the palm oil; the reaction temperature is 60-110 ℃, the reaction pressure is 0.5-1.5Mpa, and the reaction time is 20-60 min.
2. The method of claim 1, wherein the jet loop reactor comprises a reaction kettle, a circulation pump, a heat exchanger, and a venturi ejector; the materials in the reaction kettle sequentially pass through the circulating pump, the heat exchanger and the Venturi ejector and then circularly enter the reaction kettle; the Venturi ejector comprises an inlet section, a nozzle, a mixing section and a diffusion section which are communicated in sequence, wherein the inlet section and the nozzle are in a tapered tubular shape, tapered annular air chambers are arranged on the peripheries of the inlet section and the nozzle, and the air chambers are communicated with the mixing section; the gas chamber is communicated with a gas inlet arranged at the upper part of the reaction kettle through a gas circulating pipe; the diffusion section is in a divergent tubular shape; the specification and the size of the Venturi ejector are as follows: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38: (1.5-4): (2-6): (90-190): (800-1600), the opening angle of the diffuser section is 8-20 degrees.
3. The preparation method of claim 2, wherein the linear velocity of the fluid at the nozzle of the venturi ejector is controlled to be 90-130 m/s during the reaction.
4. The method according to claim 3, wherein the solid base is KF/MgO, KF/CaO, KF/Al2O3Or K2CO3/Al2O3(ii) a The KF/MgO takes MgO as a carrier, and KF with the MgO mass of 60% is loaded on the KF/MgO; the KF/CaO takes CaO as a carrier, and KF with 14% of the weight of the CaO is loaded on the carrier; the KF/Al2O3With Al2O3As a carrier, Al is loaded thereon2O315% by mass of KF; said K2CO3/Al2O3With Al2O3As a carrier, Al is loaded thereon2O320% by mass of K2CO3。
5. The method according to claim 3, wherein the solid base is K2CO3/Al2O3(ii) a Said K2CO3/Al2O3With Al2O3As a carrier, Al is loaded thereon2O320% by mass of K2CO3。
6. The method of manufacturing of claim 5, wherein the venturi ejector is sized to: inlet section opening inner diameter: nozzle bore diameter: the inner diameter of the closed air chamber: length of mixed section: diffusion segment length 38:3:4: 140: 1200, the opening angle of the diffuser section is 14 °.
7. The method of claim 6, wherein the molar ratio of methanol to palm oil is 8:1, adding the catalyst in an amount of 2% of the mass of the palm oil; in the reaction process, the reaction temperature is controlled to be 85 ℃, the reaction pressure is 0.9MPa, and the linear velocity of the fluid at the nozzle of the Venturi ejector is 115 m/s.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1664072A (en) * 2005-02-25 2005-09-07 江苏工业学院 Method for producing biological diesel oil by using solid base catalyst
US20090223118A1 (en) * 2005-12-02 2009-09-10 Acqua International Group Inc Method and Apparatus for Manufacturing and Purifying Bio-Diesel
US20090270657A1 (en) * 2007-04-23 2009-10-29 Evert Van Der Heide Process for the preparation of a 1,2-alkylene diol and a dialkylcarbonate
US20120157699A1 (en) * 2010-12-17 2012-06-21 Arisdyne Systems, Inc. Process for production of biodiesel
CN110052293A (en) * 2019-05-24 2019-07-26 山东建筑大学 A kind of biodiesel magnetic solid base catalyst and its preparation method and application

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1664072A (en) * 2005-02-25 2005-09-07 江苏工业学院 Method for producing biological diesel oil by using solid base catalyst
US20090223118A1 (en) * 2005-12-02 2009-09-10 Acqua International Group Inc Method and Apparatus for Manufacturing and Purifying Bio-Diesel
US20090270657A1 (en) * 2007-04-23 2009-10-29 Evert Van Der Heide Process for the preparation of a 1,2-alkylene diol and a dialkylcarbonate
US20120157699A1 (en) * 2010-12-17 2012-06-21 Arisdyne Systems, Inc. Process for production of biodiesel
CN110052293A (en) * 2019-05-24 2019-07-26 山东建筑大学 A kind of biodiesel magnetic solid base catalyst and its preparation method and application

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