JPWO2009110245A1 - Microwave chemical reaction apparatus and reaction method using the apparatus - Google Patents

Abstract

A microwave chemical reaction apparatus capable of obtaining a product with a low output for a short time and with a small number of man-hours. Granular or porous microwave absorption made of a main body 2 made of a microwave non-permeable material and having a circulation path for a liquid raw material, and activated carbon fixed in the circulation path so as to macroscopically block the circulation path It comprises a body 3, liquid feeding means 4 for circulating a liquid raw material in a certain direction in the circulation path, and a microwave generator 5 for irradiating the microwave absorber 3 with microwaves.

Description

  The present invention relates to an apparatus for heating a raw material using a microwave and promoting a chemical reaction, and this apparatus is particularly suitable for producing a biodiesel fuel by reacting a fatty acid or fat and an alcohol such as methyl alcohol. Used.

When microwaves are irradiated to a reaction raw material, the microwave has a number of advantages such as a temperature rise in a short time and uniform heating of the raw material. Therefore, it has been proposed to use it for various chemical reactions. For example, Patent Document 1 discloses an apparatus for irradiating microwaves while circulating a raw material in a tube. Patent Document 2 discloses a device including a container for stirring raw materials and a tube connected to the container for irradiating microwaves while flowing the mixture.
Special table 2006-516008 EP1404789

However, according to the embodiment, the apparatus described in Patent Document 1 requires a high output of 6 kW and 2 hours and a long time. Moreover, the apparatus described in Patent Document 2 needs to go through multiple stages such as a catalyst separation step, a neutralization step, and a washing step after the reaction. Therefore, any conventional apparatus increases the production cost of the product and is inferior in mass productivity.
Therefore, an object of the present invention is to provide a microwave chemical reaction apparatus capable of obtaining a product with a low output for a short time and with a small number of man-hours.

In order to solve the problem, the microwave chemical reaction apparatus of the present invention is
A main body made of a microwave non-permeable material and having a circulation path of a liquid raw material;
A granular or porous microwave absorber installed in the circulation path;
Liquid feeding means for circulating the liquid raw material in a certain direction in the circulation path;
And a microwave generator for irradiating the microwave absorber with microwaves.
In this specification, the microwave refers to an electromagnetic wave having a frequency of 3 MHz to 300 MHz.

  According to the apparatus of the present invention, since the main body is made of a microwave non-permeable material, the main body can be designed by selecting a material that is mechanically high in strength and excellent in resistance to a reaction system, such as stainless steel. . When the microwave absorber (hereinafter also referred to as “absorber”) is irradiated with microwaves while circulating the liquid raw material, the absorber is heated to a high temperature with a low output. Therefore, the liquid raw material passing through the absorber reacts quickly on the interface with the absorber. The unreacted raw material is uniformly mixed while circulating around the circulation path, and reacts when passing through the absorber again. Therefore, the reaction proceeds almost stoichiometrically. The absorber may be a solid that has a high dielectric loss, magnetic loss, or conductive loss. Metal oxide such as activated carbon, iron oxide, and alumina, metal nitride such as silicon nitride, and metal carbide such as silicon carbide. As well as mixtures thereof.

  The microwave absorber is preferably fixed in the circulation path so as to macroscopically block the circulation path. This is because the raw material is forced to pass through the gaps or pores between the granules constituting the absorber and touches the absorber. The porous microwave absorber preferably has a honeycomb structure. This is because a single block formed into a honeycomb shape can macroscopically block the circulation path and can be easily attached to and detached from the circulation path. The microwave absorber may carry an acid catalyst, a Lewis acid catalyst, an alkali catalyst, or a Lewis base catalyst. Since it is carried by the absorber, acid and alkali do not dissolve in the liquid, and a neutralization step and a washing step after the reaction are unnecessary. In addition, the acid catalyst and the alkali catalyst can be separated from the liquid at the same time that the absorber is taken out.

  In a preferred mechanical configuration of the present invention, the circulation path is formed together with the U-shaped pipe by communicating the U-shaped pipe with the main body standing in the vertical direction and the straight pipe portions of the U-shaped pipe at their intermediate positions. The liquid feeding means is attached to the upper end of the first straight pipe portion, and the microwave generator is attached to the upper end of the second straight pipe portion. According to this configuration, the gravity acting on the liquid is suppressed from flowing toward the microwave generator. Therefore, it is possible to directly irradiate the liquid raw material without attenuation of the microwave from the microwave transmission source (magnetron) without using the microwave transmitting material. However, even if one of the second straight pipe part and the microwave generator has a microwave permeable gas impermeable filter that prevents the gas generated in the main body from reaching the microwave transmission source. Good. Examples of the microwave permeable gas impermeable material include a fluororesin.

  Further, the liquid feeding means is an impeller having a rotation shaft parallel to the first straight pipe portion of the U-shaped tube, and blades are attached to a rotation shaft lower than the connection tube, and the microwave absorption The body is preferably arranged in the circulation path in the second straight pipe section. This is because the liquid can be fed while stirring the liquid by the impeller, and the liquid returned through the absorber through the connecting pipe can flow down to the upper part of the impeller by its own weight and can be fed again. It is preferable that the second straight pipe portion has an inner diameter larger than that of the first straight pipe portion because the flow resistance by the absorber is reduced. One more preferable additional element is a reflux condenser attached between the upper end of the second straight pipe portion and the connecting pipe. This is because by attaching the reflux condenser, the vaporized liquid is liquefied again and the raw material composition is stabilized. Yet another preferred additional element is a drain attached to the bent portion of the U-shaped tube. This is because the product can be removed from the drain without changing the posture of the apparatus.

Suitable reaction methods using the reactor are:
The microwave absorber is fixed at a position in the circulation path so that the microwave absorber is sufficiently immersed in a predetermined amount of the liquid raw material to be charged and its upper surface is within 30 cm from the liquid surface. The microwave generator is provided at a position where microwaves can be irradiated from above,
The predetermined amount of liquid raw material is charged into the main body,
The microwave absorber is irradiated with microwaves while circulating the liquid raw material.
According to this method, since the entire microwave absorber is immersed in the liquid material, the liquid material is efficiently heated. And since the distance between the upper surface of the microwave absorber and the liquid surface is within 30 cm, by irradiating the microwave from above the absorber, the microwave penetrates the liquid raw material on the absorber and is almost attenuated. Without being absorbed by the absorber.

  It is possible to obtain a product with low output in a short time and with a small number of man-hours in various reactions requiring thermal energy such as esterification, transesterification, nucleophilic substitution, electrophilic substitution, non-electrophilicity, non-nucleophilicity, transfer, and elimination. As a result, the product can be provided at low cost.

It is a lineblock diagram showing the microwave chemical reaction device concerning an embodiment. It is a partially broken front view which shows the principal part of the apparatus. It is a partially broken left side view. FIG. 4 is an enlarged cross-sectional view of a part IV in FIG. 2.

Explanation of symbols

1 Microwave Chemical Reactor 2 Body 3 Activated Carbon Honeycomb 4 Impeller 5 Microwave Generator 6 Reflux Cooler

  FIG. 1 is a block diagram showing a microwave chemical reaction apparatus (hereinafter referred to as “apparatus”) according to an embodiment, FIG. 2 is a partially broken front view showing the main part of the apparatus, and FIG. FIG. 4 is an enlarged cross-sectional view of a portion IV in FIG. The apparatus 1 includes a main body 2 made of stainless steel, an activated carbon honeycomb 3 as a microwave absorber, an impeller 4 as a liquid feeding means, a microwave generator 5, and a reflux cooler 6.

  The main body 2 is a connecting pipe 22 that forms a circulation path together with the U-shaped pipe 21 by communicating the U-shaped pipe 21 standing in the vertical direction and the straight pipe portions 21a, 21b of the U-shaped pipe 21 at their intermediate positions. It consists of. An electric motor 41 as a drive source of the impeller 4 is disposed on the straight pipe portion 21a, and the rotating shaft 42 of the impeller 4 penetrates the upper end surface of the straight pipe portion 21a in a liquid-tight manner via a bearing 46 and is downward. It extends. A thrust bearing 21b having a cross shape in plan view that supports the tip of the rotating shaft 42 is fixed to the inner surface of the lower end of the straight pipe portion 21a. Blades 43, 44 and 45 are attached to the outer peripheral surface of the rotating shaft 42 at a position lower than the connection port of the connecting pipe 22. The upper and lower blades 43 and 45 are orthogonal to the middle blade 44 in plan view.

  The inner diameter of the straight pipe portion 21b is twice that of the straight pipe portion 21a. A net 21d is fixed to the inner surface of the straight pipe portion 21b, and a columnar activated carbon honeycomb 3 having a thickness of 7 cm and an outer diameter substantially equal to the inner diameter of the straight pipe portion 21b is placed thereon. The position of the net 21d in the vertical direction in the straight pipe portion 21b can be changed, and is determined according to the thickness of the activated carbon honeycomb 3 and the raw material to be charged. The upper surface of the activated carbon honeycomb 3 is at a position lower by about 5 mm than the lower end of the connection port of the connecting pipe 22. A waveguide 51 of the microwave generator 5 is liquid-tightly attached to the upper end of the straight pipe portion 21b. The attachment opening of the waveguide 51 is closed by a fluororesin filter 52 so that the fluid in the main body 2 does not enter the waveguide 51. And the reflux cooler 6 is attached to the outer peripheral surface of the straight pipe part 21b between the upper end of the straight pipe part 21b and the connection port of the connecting pipe 22, and the circumferential direction 90 degree | times rotation position and 180 rotation position respectively A first charging port 21e and a second charging port 21h are provided.

A drain 21 g is provided in the curved pipe portion 21 f of the U-shaped pipe 21 facing the connecting pipe 22. Further, thermometer protection tubes 7a and 7b are liquid-tightly attached to the upper end surface and the lower end side surface of the straight tube portion 21b so as to protrude into the straight tube portion 21b, respectively. Safety valves 7c and 7d are attached to the vicinity of the upper end of the straight pipe portion 21a and the reflux cooler 6, respectively.
Depending on the type of reaction, the activated carbon honeycomb 3 may contain paratoluenesulfonic acid, paratoluenesulfonic acid derivative, acid catalyst such as sulfuric acid, Lewis acid catalyst such as ferric chloride, alkali such as potassium hydroxide and sodium hydroxide. A catalyst or Lewis base catalyst is supported.

A procedure for causing a chemical reaction using the apparatus 1 will be described below by taking biodiesel fuel production as an example.
Waste oil A containing fatty acid triglyceride is passed through a filter 8 and stored in a polyethylene waste oil tank 9 and methanol B in a polyethylene methanol tank 10. Separately, para-toluenesulfonic acid is dissolved in methanol, and the activated carbon honeycomb 3 is dipped in this so that the activated carbon honeycomb 3 carries para-toluenesulfonic acid. The activated carbon honeycomb 3 is placed on the net 21d in the straight pipe portion 21b, and the waste oil A and methanol B are introduced into the main body 2 from the waste oil tank 9 and the methanol tank 10 through the respective charging ports at a predetermined ratio. The input amount is determined so that the liquid level is 5 to 10 cm higher than the upper surface of the activated carbon honeycomb 3. Thereafter, the safety valves 7c and 7d are opened, the cooling water is introduced into the reflux cooler 6 from the cooling water inlet 61, discharged from the cooling water outlet 62, and the motor 41 is energized to rotate the impeller 4 while introducing it. The activated carbon honeycomb 3 is irradiated with microwaves of 2.45 GHz from the microwave generator 5 through the wave tube 51.

  The introduced waste oil A and methanol B become a mixture in which fatty acid triglyceride and methanol are mixed at the molecular level by the action of the impeller 4, and from the straight pipe part 21a to the straight pipe part 21b through the curved pipe part 21f. It is sent, passes through the activated carbon honeycomb 3, and returns to the straight pipe portion 21 a through the connecting pipe 22. The electromagnetic energy of the microwave is absorbed by the activated carbon honeycomb 3 and changed into heat, and the activated carbon honeycomb 3 is rapidly heated. For this reason, when the mixture passes through the activated carbon honeycomb 3, a methyl esterification reaction of fatty acid occurs at the interface between the activated carbon honeycomb 3 and the liquid raw material by the catalytic action of paratoluenesulfonic acid. The unreacted mixture is circulated through the circulation path again and used for the reaction. When the reaction is completed, the drain 21g is opened and the product fatty acid methyl ester is taken out.

  Since there is almost no obstacle between the waveguide 51 and the activated carbon honeycomb 3, the microwave is irradiated to the activated carbon honeycomb 3 with almost no attenuation. Since the raw material vaporized with the temperature rise of the activated carbon honeycomb 3 is liquefied again by the reflux cooler 6, the raw material composition does not change. The para-toluenesulfonic acid remains supported on the activated carbon honeycomb 3 even after the reaction is completed, and is not mixed into the product. Therefore, the product can be used as biodiesel fuel as it is. The loading of paratoluenesulfonic acid on the activated carbon honeycomb 3 may be performed in a state where the activated carbon honeycomb 3 is placed on the net 21d. In this case, methanol used for loading can be reused as a raw material for esterification. .

Claims (15)

A main body made of a microwave non-permeable material and having a circulation path of a liquid raw material;
A granular or porous microwave absorber installed in the circulation path;
Liquid feeding means for circulating the liquid raw material in a certain direction in the circulation path;
A microwave chemical reaction device comprising: a microwave generator for irradiating the microwave absorber with microwaves.   The apparatus according to claim 1, wherein the microwave absorber is fixed in the circulation path so as to macroscopically block the circulation path.   The apparatus according to claim 1, wherein the microwave absorber is made of one or more selected from activated carbon, metal oxide, metal nitride, and metal carbide.   The apparatus according to claim 1, wherein the porous microwave absorber has a honeycomb structure.   The apparatus according to claim 1, further comprising an acid catalyst, a Lewis acid catalyst, an alkali catalyst, or a Lewis base catalyst supported on the microwave absorber.   The apparatus according to claim 1, wherein the liquid feeding means is an impeller having a rotation axis parallel to the circulation path direction.   The apparatus of claim 1, wherein the microwave impermeable material is stainless steel.   The main body is composed of a U-tube standing in a vertical direction and a connecting pipe that forms the circulation path together with the U-shaped pipe by communicating the straight pipe portions of the U-shaped pipe at their intermediate positions. The apparatus according to claim 1, wherein the liquid feeding means is attached to an upper end of the straight pipe portion, and the microwave generator is attached to an upper end of the second straight pipe portion.   The one of the second straight pipe portion and the microwave generator has a microwave permeable gas impermeable filter that prevents gas generated in the main body from reaching the microwave transmission source. The device described.   The liquid feeding means is an impeller having a rotating shaft parallel to the first straight pipe portion, and blades attached to a rotating shaft lower than the connecting pipe, and the microwave absorber is a second straight pipe. The apparatus according to claim 8, wherein the apparatus is disposed in the circulation path in a pipe section.   The apparatus according to claim 10, wherein the second straight pipe portion has a larger inner diameter than the first straight pipe portion.   The apparatus according to claim 8, further comprising a reflux cooler attached between the upper end of the second straight pipe portion and the connecting pipe.   The apparatus according to claim 8, further comprising a drain attached to a bent pipe portion of the U-shaped pipe.   The apparatus according to claim 1, wherein the liquid raw material is a fatty acid or a mixture of fat and oil and methyl alcohol. A main body made of a microwave non-permeable material and having a circulation path of a liquid raw material, a granular or porous microwave absorber, a liquid feeding means for circulating the liquid raw material in a certain direction in the circulation path, and the micro Prepare a microwave generator that irradiates the wave absorber with microwaves,
The microwave absorber is fixed at a position in the circulation path so that the microwave absorber is sufficiently immersed in a predetermined amount of the liquid raw material to be charged and its upper surface is within 30 cm from the liquid surface. The microwave generator is provided at a position where microwaves can be irradiated from above,
The predetermined amount of liquid raw material is charged into the main body,
A microwave chemical reaction method, wherein the microwave absorber is irradiated with microwaves while circulating a liquid raw material.

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