RU2521343C1 - Method of vegetable oil re-etherification - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of a vegetable oil re-etherification includes introduction in a reactor heated up to 60°C of a vegetable oil, methyl alcohol in molar ratio 1:6, potassium hydroxide, taken in a quantity 1-3% of the oil volume, with the following mixing of a reaction mass. Mixing of the reaction mass is realised in a vortex device by interaction of two vortex streams, which move along the axis of the device towards each other.

EFFECT: application of the claimed method will make it possible to simplify technology of the vegetable oil re-etherification, reduce costs for its carrying out with preservation of high output and quality of the target product without considerable increase of reaction time.

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Description

The invention relates to a method for producing biodiesel using the transesterification process of vegetable oil and can be used in the petrochemical and fuel industries to obtain components of liquid biodiesel synthesized from renewable raw materials of plant origin.

A known method for carrying out the transesterification reaction, comprising mixing a vegetable oil heated to 50-80 ° C and a solution of alkali (catalyst) in alcohol. The reaction mass is stirred for some time (up to 2 hours), then defend until complete separation of the ether and glycerol phases. The upper ether layer is separated, neutralized with a solution of inorganic acid, washed with water [Stopsky N.A. Chemistry of fats and processed products of fatty raw materials: Textbook / N.A. Stopsky. - M .: Kolos, 1992. - 285 p.]. The duration of the transesterification process does not allow to realize in this case a continuous scheme for the production of biodiesel. One way to increase the speed and reduce the reaction time is to increase the temperature and pressure during the process. A known method for the production of biodiesel fuel (RU 2412236 C2, C11C 3/04 dated 12/15/2008) by transesterification of vegetable oil with ethyl alcohol in a reactor at a temperature of 250-280 ° C, a pressure of 15-20 MPa, for 5-10 minutes. Then the mixture is cooled and fed to the extractor. The extraction is carried out with carbon dioxide under supercritical conditions at a flow rate of carbon dioxide of 20-35 l / h, a temperature of 240-260 ° C and a pressure of 15-20 MPa.

A significant disadvantage of this method is the complexity of the hardware design and high energy consumption to achieve high temperatures and pressures.

The duration of the transesterification process is due to the fact that the components of the reaction mass — vegetable oil and alcohol — are immiscible reaction reagents. At the initial stage, the reaction mass consists of two phases (alcohol and lipid). Heterogeneous reactions do not occur in the entire volume of the system, but only in the volume of one of the phases (in our case, lipid) as a result of the diffusion of a component from another phase (alcohol) into it. The kinetics of the process at the beginning of the reaction is controlled by the mass transfer of reagents by diffusion. Therefore, an increase in the reaction rate can be achieved by intensifying mass transfer and turbulizing the flow.

The closest is the method for transesterification of vegetable oils (RU 2425863 C2, C11B 3/00 dated 09/15/2009), according to which, to intensify the process of transesterification of vegetable oils, the process is carried out by applying a rotating electromagnetic field that creates a vortex layer of ferromagnetic particles. The presence in the reaction mass of ferromagnetic particles, intensively moving in a rotating electromagnetic field and forming a vortex layer, leads to an increase in the area of contact between the alcohol and lipid phases. With the intensification of mixing under the action of friction, the thickness of the boundary layer decreases, which leads to an increase in the numerical values of the diffusion coefficient. The influence of an electromagnetic field leads to the activation of reacting particles, which increases the reaction rate and reduces the transesterification time to 10 seconds. The disadvantages of this transesterification method include attrition of ferromagnetic particles and the associated increased wear of the reactor, the need to create a special reactor cooling system.

The objective of the invention is to simplify the technology for transesterification of vegetable oil, reducing the cost of its implementation while maintaining a high yield and quality of the target product and without a significant increase in reaction time.

The solution to this problem is achieved by the fact that in the method of transesterification of vegetable oil, which involves introducing into the reactor heated to 60 ° C vegetable oil, methyl alcohol in a molar ratio of 1: 6, potassium hydroxide taken in an amount of 1-3% of the oil volume, followed by by mixing the reaction mass, according to the invention, the reaction mass is mixed in a vortex device due to the interaction of two vortex flows moving along the axis of the device towards each other.

The process of transesterification of vegetable oils is carried out in a vortex device. In a vortex device, intensification of mixing is achieved, but not due to the movement of ferromagnetic particles, but as a result of the interaction of two vortices moving along the device’s axis towards each other: a peripheral one, rotating according to the law of a potential vortex, and an axial one, rotating according to the law of a quasi-solid body (See, for example , A. P. Merkulov. Vortex effect and its application in engineering. Publishing house "Engineering". - M., 1969. - 183 p.). The decisive role in the energy transfer from the axial to peripheral layers is given to the microcavitation process, which is formed in a vortex medium, in which the energy is released due to the “collapse” of the cavities formed in the liquid filled with gas and turbulent pulsations, their radial component. Even in those parts of the chamber where the statistical temperature at the flow axis is lower than the temperature of the peripheral layers, radial pulsations transfer heat upward along the radius. The turbulent pulsating effect resulting from this leads to the activation of methanol molecules and triacylglycerols of vegetable oil.

The invention is illustrated by drawings, where figure 1 presents a design diagram of a vortex device; figure 2 is a cross section aa of the chamber of the vortex device.

The vortex device comprises a housing 1 and a chamber 2 with tangentially connected nozzles 3 and 4, a diaphragm 5 is attached to the chamber 2, a cover 6 is installed on the back of the housing for technological maintenance of the vortex device.

The method is as follows.

Vegetable oil is supplied through the supply pipe 3, at the same time, a pre-prepared solution of potassium hydroxide in methyl alcohol is supplied through the pipe 4. Mixing is carried out in chamber 2, with further passage of the reaction mass through the volume of the housing 1, further mixing occurs due to the intense interaction of peripheral and axial flows. The output of the transesterification reaction products is carried out through the diaphragm 5.

The essence of the proposed method with the best results is described in the example.

Example.

100 g of sunflower oil heated to a temperature of 60 ° C and a solution of 1.4 g of potassium hydroxide in 20 g of methyl alcohol are introduced into the vortex device through nozzles 3 and 4 under pressure P = 0.2 MPa. The components of the reaction mass are mixed in the chamber 2, then the reaction mass passes through the volume of the housing 1, where it is further mixed due to the intense interaction of peripheral and axial flows. The output of the transesterification reaction products is carried out through the diaphragm 5. The resulting products are defended, the upper ether layer is separated, neutralized with a solution of phosphoric acid, washed with water. A mixture of biodiesel components (fatty acid methyl esters) is obtained in 99% yields. The reaction time is 60 s.

The result of using the present invention is to simplify the technology for transesterification of vegetable oil, reducing the cost of its implementation while maintaining a high yield and quality of the target product and without a significant increase in reaction time.

Claims (1)

A method for transesterification of vegetable oil, comprising introducing into the reactor heated to 60 ° C vegetable oil, methyl alcohol in a molar ratio of 1: 6, potassium hydroxide taken in an amount of 1-3% of the volume of oil, followed by stirring of the reaction mixture, characterized in that mixing the reaction mass is carried out in a vortex device due to the interaction of two vortex flows moving along the axis of the device towards each other.

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