JP7572702B2 - Microwave processing device, microwave processing method, and chemical reaction method - Google Patents

Description

The present invention relates to a microwave processing device, a microwave processing method, and a chemical reaction method.

Microwaves have spread from household use such as microwave ovens, and have since been researched and developed for use in industrial heating systems. For example, when used as a heating system, microwave irradiation directly heats the object being treated, allowing heating in a short time and reducing temperature unevenness caused by thermal conduction. Further advantages include the ability to heat without contact and the ability to selectively heat only those objects that absorb microwaves well.

Microwaves, which are electromagnetic waves, tend to cause uneven heating because their energy intensity changes with wavelength periods. In order to address this problem of uneven heating, the use of standing microwave waves has been considered. For example, Patent Document 1 describes a microwave heating device using a cavity resonator. In this technology, an axially symmetric microwave electric field parallel to the central axis is generated in a cylindrical cavity resonator, and a chemical reaction is caused to proceed in a circular tube arranged in a portion where the electric field intensity is concentrated. Patent Document 2 describes a flow-type microwave-utilizing chemical reaction device in which a flow tube is arranged along a portion where the electric field intensity of a single-mode standing wave formed in the cavity resonator is maximized, and the fluid is caused to flow in the flow tube, thereby heating the fluid quickly and uniformly. Furthermore, Patent Document 3 describes the use of a feedback control means that controls the oscillation frequency of a microwave generator to match the current resonance frequency of the cavity resonator. It is said that this allows the resonance state of TM ₀₁₀ to be constantly maintained, enabling high-precision heat treatment.
A technique has been developed in which a cavity resonator is used in this way to form a standing wave therein, thereby uniformly and efficiently heating an object to be processed.

JP 2005-322582 A JP 2010-207735 A JP 2009-80997 A

When an object to be treated is heated by standing microwave waves, the object absorbs the microwaves and generates heat, so the microwave energy is attenuated by heating the object. If the volume of the object to be treated occupies a large part of the cavity resonator that forms the standing waves, the microwave energy is also attenuated significantly, making it difficult to form a standing wave, which is a composite wave of the incident wave and the reflected wave. For this reason, there is a limit to the size of the object to be treated that can be treated using standing microwave waves.
For example, in the above-mentioned Patent Document 2, the inner diameter of the reaction tube in which the object to be treated is heated to cause a chemical reaction is set to 2.9 mm or less, and in a reaction tube with an inner diameter larger than that, it is difficult to heat the object to be treated to a desired temperature with high energy efficiency by the standing waves of microwaves. In the case of mass-producing a target product as a reaction product by circulating a fluid as the object to be treated through the reaction tube and heating the object in the reaction tube by the standing waves of microwaves, if the inner diameter of the reaction tube is small, it is necessary to increase the flow rate to improve production efficiency. As a result, a considerable pressure load is applied to the liquid delivery device. In addition, when the object to be treated is a highly viscous fluid or slurry and is heated while being circulated through the reaction tube, if the inner diameter of the reaction tube is small, the liquid delivery may not be possible.

The present invention aims to provide a microwave processing device that utilizes standing waves of microwaves to heat substantially the entire object to be processed, which is arranged over a much wider area than conventional standing wave heating, including the technology described in the above patent document, with excellent energy efficiency. The present invention also aims to provide a microwave processing method and a chemical reaction method that utilize the microwave processing device.

The above object of the present invention is achieved by the following means.
[1]
A microwave processing apparatus for irradiating a microwave into a cavity resonator to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more) in the cavity resonator,
The microwave has a frequency of 300 to 1000 MHz;
A microwave processing apparatus in which an object to be processed is placed along a portion where the electric field strength of the standing wave is maximized.
[2]
The microwave processing apparatus according to claim 1, wherein the object has a maximum length of 100 mm or less in a direction perpendicular to a direction in which the electric field strength of the standing wave is constant.
[3]
The microwave processing apparatus according to [1] or [2], wherein the cavity resonator that forms the standing wave of the TM _0n0 mode has a dimension of a microwave irradiation space of the cavity resonator in a direction in which the electric field strength of the standing wave is constant, the dimension being equal to or less than half the wavelength of the microwave.
[4]
The microwave processing apparatus according to any one of [1] to [3], further comprising a feedback control unit that causes a frequency of the microwave supplied into the cavity resonator to coincide with a frequency of a standing wave formed in the cavity resonator.
[5]
The microwave processing apparatus according to any one of [1] to [4], wherein a tube is arranged along a position where the electric field strength in the standing wave of the TM _0n0 mode is maximized, and the object to be processed is placed in the tube.
[6]
The microwave processing apparatus according to any one of [1] to [5], further comprising a loop antenna or a monopole antenna for supplying microwaves to a microwave irradiation space within the cavity resonator.
[7]
The microwave processing apparatus according to any one of [1] to [6], wherein the microwave processing apparatus is a chemical reaction apparatus that processes the object to be processed with microwaves to cause a chemical reaction.
[8]
A plurality of the cavity resonators are arranged in series,
an object to be processed is disposed through the plurality of cavity resonators in a direction in which the plurality of cavity resonators are connected in series and along a portion where an electric field intensity of a standing wave formed in the plurality of cavity resonators is maximized;
The microwave processing apparatus according to any one of [1] to [7], further comprising a microwave generator that supplies microwaves to each of the plurality of cavity resonators.
[9]
A microwave processing method for irradiating a cavity resonator with microwaves to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more) in the cavity resonator, and processing an object to be processed by using the standing wave, comprising:
The microwave has a frequency of 300 to 1000 MHz;
A microwave processing method in which the object to be processed is placed along a portion where the electric field strength of the standing wave is maximized.
[10]
The microwave processing method according to [9], wherein the temperature of the object to be processed is controlled during the processing of the object to be processed.
[11]
The microwave processing method according to [9] or [10], wherein a reaction involving the object to be processed is promoted or stopped by controlling a temperature of the object to be processed.
[12]
A chemical reaction method for treating an object to be treated by irradiating a microwave into a cavity resonator to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more) in the cavity resonator, comprising the steps of:
The microwave has a frequency of 300 to 1000 MHz;
A chemical reaction method comprising: placing the object to be processed along a portion where the electric field strength of the standing wave is maximized; and processing the object to be processed to cause a chemical reaction.

According to the microwave processing apparatus and microwave processing method of the present invention, the object to be processed can be arranged over a much larger area than in the past, and substantially the entire object to be processed can be processed with excellent energy efficiency.
Furthermore, according to the chemical reaction method of the present invention, the objects to be processed that are involved in the chemical reaction are arranged in a much larger area than in the past, and almost the entire objects to be processed are processed with excellent energy efficiency, thereby making it possible to cause a chemical reaction to occur efficiently and with high precision.

1 is a schematic cross-sectional view showing a preferred embodiment of a basic form of a microwave processing apparatus according to the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of a microwave processing apparatus of the present invention in which cavity resonators are arranged in series. 1 is a graph showing the rate of temperature rise per unit microwave output when ethylene glycol is heated by standing waves of microwaves in the 915 MHz band. FIG. 13 shows a difference in the waveform of S21 depending on the inner diameter of a reaction tube when the reaction tube is filled with ethylene glycol and heated by standing waves of microwaves in the 915 MHz band. This figure shows the temperature rise characteristics when ethylene glycol, as the object to be heated, is circulated through a tube at high speed and heated by standing waves of microwaves in the 915 MHz band. 1 is a graph showing the rate of temperature rise per unit microwave output when ethylene glycol is heated by standing waves of microwaves in the 2.45 GHz band. FIG. 13 is a diagram showing a difference in the waveform of S21 depending on the inner diameter of a reaction tube when the reaction tube is filled with ethylene glycol and heated by standing waves of microwaves in the 2.45 GHz band. This is a diagram showing the temperature rise characteristics when ion-exchanged water, which is an object to be heated, is circulated through a pipe at high speed and heated by standing waves of microwaves in the 915 MHz band. FIG. 1 shows the temperature rise characteristics, i.e., the time changes of temperature, incident microwave waves, reflected microwave waves, and resonant frequency, when N,N-dimethylacetamide is used as the heated object and heated by microwaves. FIG. 1 shows the case where the microwave output is 40 W, FIG. 1 shows the case where the microwave output is 60 W, and FIG. 1 shows the case where the microwave output is 80 W. FIG. 13 is a diagram showing the waveform of S21 depending on the inner diameter of a reaction tube when toluene is filled in the reaction tube and microwave heating is performed in the 915 MHz band. 1 is a schematic cross-sectional view showing a preferred embodiment of a microwave processing apparatus of the present invention for heating an object to be heated in a test tube. FIG. 1 shows the temperature rise characteristics when the following liquid is heated as the heated object with microwave outputs of 20 W, 50 W, 100 W, and 200 W. FIG. 1 shows the temperature rise characteristics when ion-exchanged water is used, FIG. 1 shows the temperature rise characteristics when 1-methyl-2-pyrrolidone (boiling point 202° C.) is used, and FIG. 1 shows the temperature rise characteristics when N,N-dimethylacetamide is used. FIG. 13 is a diagram showing temperature rise characteristics when a reaction tube is filled with carbon powder as an object to be heated and heated using microwaves in the 915 MHz band and 2.45 GHz band. FIG. 13 is a diagram showing the waveform of S21 of a network analyzer when a reaction tube filled with carbon powder is heated using microwaves in the 915 MHz band. FIG. 13 is a diagram showing the waveform of S21 of a network analyzer when a reaction tube filled with carbon powder is heated using microwaves in the 2.45 GHz band. FIG. 13 shows the waveform of S21 of a network analyzer depending on the inner diameter of a reaction tube when a cavity resonator having an inner diameter smaller than that of Example 1 is used, the reaction tube is filled with ethylene glycol, and heated using microwaves having a frequency of 950 MHz to 980 MHz. FIG. 11 is a schematic cross-sectional view showing the basic form of the microwave processing device 1 (1D) used in Example 8. FIG. 13 is a relationship diagram showing the temperature vs. time relationship illustrating the temperature rise characteristics when ion-exchanged water is heated in Example 8. FIG. 13 is a relationship diagram between temperature and time, showing the temperature rise characteristics when the zeolite raw material liquid in Example 9 was subjected to microwave heating synthesis. FIG. 13 is a diagram showing an X-ray diffraction pattern of a synthetic product obtained by microwave heating synthesis of a zeolite raw material liquid in Example 9, in which the vertical axis shows diffracted X-ray intensity (Intensity) and the horizontal axis shows diffraction angle (2θ degree/CuKn).

The following describes a preferred embodiment of the microwave processing device of the present invention with reference to the drawings.

[Microwave Processing Device]
1, a microwave processing apparatus 1 (1A) has a cavity resonator 2 and microwave supply means 3 for supplying microwaves of a frequency capable of forming a standing wave in the cavity resonator 2. The microwave supply means 3 includes a microwave generator 4 for generating microwaves, and an antenna 5 for supplying the output microwaves into the cavity resonator 2. The microwave generator 4 is provided with a microwave oscillator for oscillating microwaves, and may further include a control unit 11 for controlling the microwave oscillator, an attenuator for adjusting the attenuation level of the microwave, an amplifier (not shown) for amplifying microwave power, an isolator for absorbing reflected waves, a matching device (not shown) for suppressing reflected waves, and the like.
The cavity resonator 2 forms a standing wave in the microwave irradiation space 2A therein. The standing wave has a single mode of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more).
For example, the energy (electric field strength) of the standing wave formed in the cavity resonator 2 at the central axis C of the cylindrical microwave irradiation space 2A is maximized. The standing wave energy is uniform in the direction of the central axis C. The tube 6 is arranged along the portion where this energy is maximized and uniform or its vicinity. The object to be processed 31 (indicated by an arrow in the drawing) is arranged in the tube 6. For example, in the case of a cylindrical cavity resonator 2 in which a standing wave of the TM _0n0 mode (n is an integer of 1 or more) is generated, the electric field strength is maximized at the central axis C and is uniform along the central axis C. For this reason, it is preferable that the tube 6 is arranged along the central axis C. The object to be processed 31 is arranged in the internal space 6A of the tube 6. The object to be processed 31 is arranged in the internal space 6A, which means that the object to be processed 31 exists in the internal space 6A, and includes a state in which the object to be processed 31 is stationary in the tube 6 and a state in which the object to be processed 31 is flowing in the tube 6. The object to be treated 31 may or may not fill the entire inside of the pipe 6 .
1 shows a configuration in which the pipe 6 is provided, but depending on the type of the object to be treated, the object to be treated may be disposed in a self-supporting state without the pipe 6. Furthermore, as long as the object to be treated is not circulated through the pipe 6, the pipe 6 does not need to have a shape with a hole therethrough, and may have, for example, a shape with one end closed (such as the shape of a test tube).

It is preferable that the microwave supply port 2S has an antenna 5 capable of applying a high frequency wave. The antenna 5 is connected to a microwave oscillator 4 via a cable 7.
Microwaves emitted from a microwave oscillator 4 can be supplied from an antenna 5 through a cable 7 into the cavity resonator 2. The microwave power can be adjusted by the microwave generator 4 and an amplifier (not shown), thereby making it possible to control the electric field intensity distribution of the standing wave formed in the cavity resonator 2.
The standing wave may be a frequency at which a standing wave of the above-mentioned TM mode or TE mode is formed within the cavity resonator 2 .
1, a microwave supply port using a waveguide may be provided instead of the antenna 5. By connecting a rectangular waveguide or a cylindrical waveguide capable of transmitting the frequency of the microwave to be supplied to the cavity resonator via an iris having an appropriate opening, microwave energy from a microwave oscillator can be introduced into the cavity resonator.
It should be noted that each of the above forms describes one example of the microwave processing device 1 of the present invention, and the microwave processing device 1 of the present invention is not limited to the above forms in any way except as specified in the present invention.

The frequency of the microwaves supplied into the microwave irradiation space 2A is 300 to 1000 MHz, preferably 700 to 1000 MHz, and more preferably 915 MHz microwaves. In the present invention, the 890 to 1000 MHz band is referred to as the 915 MHz band. By irradiating microwaves of the above frequency, it is possible to form a wide processing area in the width direction (perpendicular to the central axis C) of the object to be processed, as described below. This frequency range includes a band designated as the ISM band (Industrial, Scientific and Medical Use) for dielectric heating including microwave heating and high frequency (dielectric) heating. In the following description, when the 915 MHz band is described, the same effect can be obtained at 300 to 1000 MHz.
In addition, the cavity resonator 2 forming the standing wave of the TM _0n0 mode preferably has a dimension (height) H of the microwave irradiation space 2A in a direction (direction of the central axis C) where the electric field intensity of the standing wave is constant, for example, 1/2 of the wavelength or less. In the present invention, the "dimension H of the microwave irradiation space 2A" is the length where the distance from a certain point on the upper surface to a certain point on the lower surface constituting the microwave irradiation space 2A in parallel with the direction of the central axis C is maximum. In this way, the thickness of the cavity resonator 2 in the direction of the central axis C can be made compact. As a result, a microwave processing apparatus having a configuration in which the cavity resonators are stacked, a microwave generator is provided for each of the stacked cavity resonators, and microwaves are irradiated to each cavity resonator, thereby increasing the energy density in the cavity resonator and enabling more efficient heat processing.

The maximum length of the internal space 6A of the tube 6 in the direction perpendicular to the central axis C (the inner diameter when the cross section of the tube 6 is circular) is not particularly limited as long as a standing wave can be formed in the cavity resonator. For example, it can be 100 mm or less, preferably 50 mm or less, more preferably 20 mm or less, even more preferably 10 mm or less, and may be 8 mm or less. The maximum length of the tube 6 is usually 0.2 mm or more, preferably 0.5 mm or more, more preferably 2 mm or more, even more preferably 2.5 mm or more, and particularly preferably 3 mm or more.
The preferred range of the maximum length of the object to be treated in the direction perpendicular to the central axis C is the same as the maximum length of the internal space 6A of the tube 6 in the direction perpendicular to the central axis C. In this case, the object to be treated may be disposed in the tube 6, and depending on the type of the object to be treated (for example, when the object to be treated can maintain its shape even if it is not surrounded by the tube 6), the object to be treated may be disposed in the cavity resonator without providing the tube 6. In the present invention, the "maximum length of the internal space 6A of the tube 6 in the direction perpendicular to the central axis C" is the length at which the distance from one point to another point is maximum on the inner circumference of the cross section of the tube 6 in the direction perpendicular to the central axis C (the outer circumference of the cross section of the internal space 6A). Also, the "maximum length of the object to be treated in the direction perpendicular to the central axis C" is the length at which the distance from one point to another point is maximum on the outer circumference of the cross section of the object to be treated in the direction perpendicular to the central axis C.

In the microwave processing device 1, microwaves are supplied from a microwave generator 4 to a cavity resonator 2 having a tube 6 through which an object to be processed (not shown) exists or flows, and the above-mentioned standing wave is formed in the cavity resonator 2. For example, by providing the tube 6 along a portion where the electric field strength of the standing wave is at a maximum, the object to be processed 31 in the tube 6 can be processed with high energy efficiency. In the microwave processing device 1, the microwaves that form the standing wave are supplied into the microwave irradiation space 2A from a microwave supply port 2S provided in the cavity resonator 2.

The frequency of the standing wave is a frequency in the 915 MHz band, and it is sufficient if a standing wave can be formed in the cavity resonator 2. When microwaves having a frequency in the 915 MHz band are supplied from the microwave supply port 2S, a standing wave in the TM mode or TE mode as described above is formed in the cavity resonator 2. In the case of heating in which the peak of the electric field intensity is located on the central axis C, it is preferable that a standing wave in the TM _0n0 mode is formed, and it is more preferable that standing waves in the TM ₀₁₀ , TM ₀₂₀ , and TM ₀₃₀ modes are formed. Among these, it is even more preferable that a standing wave in the TM ₀₁₀ mode is formed, which allows the size of the cavity resonator 2 to be compact.

In the microwave processing apparatus 1A, the microwaves supplied from the microwave generator 4 are supplied with an adjusted frequency. By adjusting the frequency, the electric field intensity distribution of the standing wave formed in the cavity resonator 2 can be controlled to a desired distribution state. Also, the intensity of the standing wave can be adjusted by the output of the microwave power. In other words, it becomes possible to control the heating state of the object 31 to be processed.
Specifically, it can be preferably controlled by the control unit (feedback control unit) 11 described below. The feedback control unit 11 may be built in the microwave generator 4, or may be configured separately. This feedback control unit 11 can match the frequency of the microwave generated by the microwave generator 4 or the microwave generated by an amplifier (not shown) that amplifies the microwave to the frequency of the standing wave formed in the microwave irradiation space 2A of the cavity resonator 2. This matching preferably means a perfect match, but also includes a difference within a certain range, for example, within 2 MHz. Then, the microwave with the matched frequency is irradiated into the microwave irradiation space 2A. Therefore, it is preferable that the cavity resonator 2 is provided with a detection unit 12 that detects the frequency of the standing wave in the microwave irradiation space 2A. The detection unit 12 may be any unit that measures the energy intensity inside the microwave irradiation space 2A and processes the signal to detect the frequency.

A specific example of the control method in the feedback control unit 11 will be described. The detection unit 12 detects an output signal proportional to the energy intensity of the microwave in the microwave irradiation space 2A. On the other hand, the microwaves supplied to the microwave irradiation space 2A are microwaves generated from the microwave generator 4 or microwaves generated from the microwave generator 4 and amplified by an amplifier. At this time, when the frequency generated from the microwave generator 4 is swept over the entire 915 MHz band or a part of the 915 MHz band, the output signal from the detection unit 12 obtains a distribution with a maximum value. This maximum value means that a standing wave has been formed in the microwave irradiation space 2A, so the resonance frequency of a specified mode can be detected by comparing it in advance with the resonance frequency of the standing wave in the TM _0n0 mode. The feedback control unit 11 causes the frequency of the microwaves generated from the microwave generator 4 to match the frequency of the detected microwaves.
Alternatively, it is also possible to use a reflected wave signal from a reflected wave detector (not shown) installed between the microwave generator 4 and the cavity resonator 2 without using the detection unit 12. In this case, a small reflected wave, that is, the frequency of the reflected wave being a minimum value, means that energy is supplied to the cavity resonator 2 and a standing wave is formed. Therefore, it is also possible to derive the microwave resonator frequency from the minimum value of the reflected microwave wave.
In this way, a microwave having a frequency that matches the resonant frequency of the microwave derived from the maximum value detected by the detection unit 12 or the minimum value detected by a reflected wave detector (not shown) is generated from the microwave generator 4. Alternatively, a microwave having a frequency that matches the resonant frequency of the detected microwave is generated from the amplifier.
Then, microwaves having a frequency that matches the resonant frequency are supplied into the microwave irradiation space 2A.
It is desirable to perform the operation for detecting the resonance frequency periodically. When the disturbance is large or when the temperature, flow rate, and composition change significantly, it is desirable to perform the operation at a short interval, for example, one second or less, immediately after the start of the microwave treatment. On the other hand, when the disturbance is small or when the temperature, flow rate, and composition change are small, it may be performed at a long interval, for example, every minute, after the microwave treatment has started and a sufficient amount of time has passed and the treatment has stabilized.
When sweeping the frequency of the microwaves from the microwave generator 4 to detect the resonant frequency, it is preferable that the sweep frequency width is narrow. However, if the fluctuation is large, a maximum value may not be found within the sweep frequency if the sweep frequency width is narrow. In that case, it is preferable to widen the sweep frequency width and perform the sweep again to detect the resonant frequency.

The configuration of the microwave processing apparatus 1 of the present invention will now be described in detail.
<Cavity resonator>
The shape of the cavity resonator 2 used in the microwave processing device is not particularly limited as long as it has one microwave supply port 2S and forms a single-mode standing wave when microwaves are supplied. For example, a cylindrical or rectangular cavity resonator can be used. In this specification, a cylindrical cavity resonator is used to mean a cavity resonator whose inner cross-sectional shape perpendicular to the central axis C of the cavity resonator is circular, as well as a cavity resonator whose cross-sectional shape is elliptical or oblong. A rectangular cavity resonator means a cavity resonator whose inner cross-sectional shape perpendicular to the central axis C is polygonal, and the cross-sectional shape is preferably 4 to 10-sided. The corners of the polygon may be rounded.
The size of the cavity resonator 2 can be appropriately designed according to the purpose in the above-described embodiment. The cavity resonator 2 is preferably one having a low electrical resistivity and is usually made of metal, and examples of the material that can be used include aluminum, copper, iron, magnesium, brass, stainless steel, and alloys thereof. Alternatively, the surface of a resin, ceramic, or metal may be coated with a material having a low electrical resistivity by plating or vapor deposition. Materials containing silver, copper, gold, tin, or rhodium can be used for the coating.

<Microwave supply>
In the microwave processing apparatus 1 of the present invention, microwaves generated by a microwave generator 4 or a microwave amplifier (not shown) are supplied from a microwave supply port 2S through an antenna 5 into a microwave irradiation space 2A of a cavity resonator 2.

The microwave generator 4 may be a microwave generator whose oscillation frequency can be adjusted within the 915 MHz band. For example, a microwave generator using a semiconductor solid-state element or a microwave generator such as a magnetron may be used. From the viewpoint of being able to finely adjust the microwave frequency, it is preferable to use a microwave generator using a semiconductor solid-state element. Examples of microwave generators using semiconductor solid-state elements include microwave generators using Gunn diodes, avalanche diodes (Impatt diodes), etc. It is also preferable to have an amplifier that amplifies the microwaves generated by the microwave generator 4. This amplifier may be a microwave amplifier using a general high-frequency field effect transistor (FET).

In the embodiment shown in Fig. 1, a cylindrical cavity resonator is used as the cavity resonator 2. A microwave supply port 2S is provided on a wall surface (inner surface of the cylinder) parallel to the central axis C of the cavity resonator 2 or in the vicinity thereof. It is preferable to have an antenna 5 capable of applying a high frequency wave to the microwave irradiation space 2A through the microwave supply port 2S. As the antenna 5, it is preferable to use a magnetic field excitation antenna, for example, a loop antenna, or an electric field excitation antenna, for example, a monopole antenna. The antenna 5 is connected to the microwave generator 4 via a cable 7. For example, a coaxial cable can be used as the cable 7.
In this configuration, microwaves emitted from the microwave generator 4 are supplied from the antenna 5 through the cable 7 into the microwave irradiation space 2A. A matching box (not shown) for suppressing reflected waves and an isolator (not shown) for protecting the microwave generator may be installed between the microwave generator 4 and the antenna 5. The function of the matching box may also be achieved by adjusting the length of the cable.
It is preferable that the end face of the antenna 5 is connected to a ground potential such as a wall surface of the cavity resonator. By applying microwaves (high frequency waves) to this antenna 5, for example, a magnetic field is excited within the loop of the loop antenna, and a standing wave can be formed within the cavity resonator.
For example, when a single mode standing wave of _TM010 is formed in the above cylindrical cavity resonator, the electric field strength is maximized at the central axis C and is uniform in the direction of the central axis C. Therefore, in the tube 6, the object to be treated 31 present or flowing therein can be uniformly and highly efficiently heated by microwaves.
Alternatively, microwaves may be supplied from the microwave generator 4 to the microwave supply port 2S using a waveguide.

<Heating of object to be treated>
In the microwave processing apparatus of the present invention, the object 31 to be processed (for example, the object 31 to be heated placed in the tube 6) is placed in correspondence with the energy (electric field) intensity of the standing wave inside the cavity resonator 2. In particular, more efficient heating is possible if the object is placed along a portion where the electric field intensity of the standing wave formed in the cavity resonator 2 is maximized.

1, the object 31 to be heated placed in the tube 6 is not particularly limited, and may be a liquid, a solid, a powder, or a mixture thereof. Alternatively, a honeycomb structure, a catalyst, or the like (not shown) previously placed in the tube 6 may be used.
When the object 31 to be heated is caused to flow through the pipe 6, the temperature of the object 31 to be heated can be continuously controlled by transporting the object 31 using a liquid delivery means (e.g., a liquid delivery pump) 41 or the like. Since the progress of many chemical reactions can be controlled by temperature, the microwave processing device 1 of the present invention can be suitably used for controlling chemical reactions.
If the object to be heated can maintain its shape by itself, it does not need to be placed in a tube. For example, if the object to be heated is a fibrous solid, it can be transported inside the resonator without being supported by a tube or the like.
When the object to be heated is a honeycomb structure, the microwave processing device can be used, for example, to control the temperature of a gaseous substance passing through the honeycomb structure. When the object to be heated is a catalyst, the microwave processing device can be used to cause a chemical reaction by the action of the catalyst, as described later. It is also preferable that the catalyst is supported on the honeycomb structure.

It is also preferable that the microwave processing apparatus 1 (1B) of the present invention has a configuration in which a plurality of cavity resonators 2 are arranged in series in the direction of the central axis C.
That is, as shown in FIG. 2, the microwave processing apparatus 1 (1B) has a configuration in which the microwave processing apparatus 1A described above is stacked in a plurality of stages, and a plurality of cavity resonators 2 are arranged in series in a stacked state. In the drawing, as an example, a configuration in which three cavity resonators 21, 22, and 23 are stacked in the vertical direction is shown. The number of cavity resonators 2 is not limited to three. The number of cavity resonators 2 can be stacked from two to several thousand. A tube 6 is arranged in the plurality of cavity resonators 2, which penetrates a part in the series connection direction and in which the energy of the standing wave formed in each cavity resonator 2 is maximized and uniform in the axial direction. In this case, an object to be heated (not shown) is arranged in the tube 6. For example, in the case of a cylindrical cavity resonator 2 in which a standing wave of the TM _0n0 mode (n is an integer of 1 or more) is generated, the electric field intensity is maximized at the central axis of the cylinder and uniform along the central axis C, so that the tube 6 is preferably arranged on the central axis C of the cylinder.
A microwave generator 4 is provided for each of the cavity resonators 2, and microwaves are individually supplied to each of the cavity resonators 2. A microwave frequency in the 915 MHz band is used.
Furthermore, it is also preferable to provide a mechanism (not shown) between the respective resonators 2 or within the resonator 2 for preventing leakage of microwaves from within the resonator 2 .

In the microwave processing device 1B, microwaves are supplied from a microwave generator 4 to a cavity resonator 2 having a tube 6 through which an object to be heated exists or flows, forming a standing wave in the cavity resonator 2. The object to be heated in the tube 6 can be heated with high energy efficiency by the microwave energy in or near the part where the electric field strength of the standing wave is maximum. In the microwave processing device 1, the microwaves that form the standing wave are supplied into the cavity resonator 2 via an antenna 5 from a microwave supply port 2S provided in the cavity resonator 2.

[Microwave treatment method]
In the microwave processing method, microwaves are irradiated into a cavity resonator to form a single mode standing wave of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more) in the cavity resonator. The object to be processed is processed using the standing wave. The microwaves used have a frequency in the 915 MHz band. The object to be processed is placed along a portion where the energy (electric field) intensity of the standing wave is maximized. In the following description of the microwave processing method, the object to be processed is described as an object to be heated.
In this microwave processing method, it is preferable to use the microwave processing apparatus 1A or 1B described above. The microwave processing apparatus 1A will be described below, but the microwave processing apparatus 1B can also be applied in the same manner as the microwave processing apparatus 1A.
Specifically, the object to be heated 31 can be heated using the microwave processing apparatus 1A. First, microwaves, the frequency of which is adjusted as described above, are supplied from the microwave generator 4 into the microwave irradiation space 2A of the cavity resonator 2. By adjusting the frequency, the electric field intensity distribution of the standing wave formed in the cavity resonator 2 can be controlled to a desired distribution state, and the strength of the standing wave can be adjusted by the output of the microwave. In other words, it becomes possible to control the heating state (temperature) of the object to be heated 31 in the reaction tube 6 (internal space 6A).
The microwave frequency is the 915 MHz band frequency, and can form a specific single mode standing wave in the microwave irradiation space 2 A. In the case of the microwave processing device 1B, the type (mode) of the standing wave formed in each resonator may be different, but it is preferable that the type (mode) of the standing wave formed in each resonator is the same.

[Chemical reaction method]
In the chemical reaction method, microwaves are irradiated into the microwave treatment space 2A in the cavity resonator 2 to form a single mode standing wave of TM _0n0 (n is an integer of 1 or more) or TE _10n (n is an integer of 1 or more) in the microwave treatment space. Then, the object to be treated is treated using the standing wave. This treatment is mainly a heat treatment, but also includes a treatment such as breaking molecular bonds by reaction. In the following explanation of the chemical reaction method, the object to be treated is described as an object to be heated. As the microwave, a microwave with a frequency of 300 to 1000 MHz is used, preferably a microwave with a frequency of 700 to 1000 MHz, and more preferably a microwave with a frequency of 915 MHz band is used. This 915 MHz band refers to a frequency range of 890 to 1000 MHz as above. It includes arranging the object to be heated along the part where the energy (electric field) intensity of the standing wave is maximum, and heating the object to be heated to cause a chemical reaction.
In the above chemical reaction method, it is preferable to use the microwave processing apparatus 1A or 1B described above. The microwave processing apparatus 1A will be described below, but the microwave processing apparatus 1B can also be applied in the same manner as the microwave processing apparatus 1A.
In the chemical reaction method, the reaction involving the object to be heated can be promoted or stopped by controlling the temperature of the object to be heated. For example, the reaction can be promoted by increasing the temperature of the object to be heated, and the reaction can be stopped by stopping the heating and decreasing the temperature.

When the microwave processing apparatus 1A is applied to a chemical reaction method, for example, a reaction raw material supply port for supplying reaction raw materials is provided at one end of a tube (also called a reaction tube) 6, and a reaction product discharge port for discharging reaction products is provided at the other end, although this is not shown in the figure. The reaction raw materials may be liquid raw materials, gaseous raw materials, or solid powder raw materials accompanying these.
Alternatively, a reaction tube 6 made of a material that transmits microwaves may be installed in the cavity resonator 2, with one end of the reaction tube 6 connected to a reaction raw material supply port and the other end connected to a reaction product discharge port. Examples of materials that transmit microwaves include glass materials such as quartz, resin materials such as Teflon (registered trademark), and ceramic materials such as alumina.
The reaction raw materials can be introduced, for example, by a liquid delivery means 41 provided at the supply port, or the raw materials can be sucked from the reaction raw material supply port by providing a suction means (for example, a suction pump) (not shown) at the discharge port.

Examples of the chemical reaction include rearrangement reaction, substitution reaction, addition reaction, cyclization reaction, condensation reaction, reduction reaction, oxidation reaction, hydrogenation reaction, catalytic reduction reaction, isomerization reaction, cleavage reaction, disproportionation reaction, catalytic decomposition reaction, selective catalytic reduction reaction, selective oxidation reaction, racemization reaction, etc. Further examples include radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, inorganic reaction, etc. used in polymer synthesis, but are not limited to these, and various other chemical reactions can be mentioned. In addition, a catalytic reaction utilizing the action of a catalyst is also preferable.
Specific examples of chemical reactions include reactions for oxidatively decomposing volatile organic substances, reactions for reducing nitrogen oxides to nitrogen and oxygen, reactions for fixing sulfur oxides to calcium, and reactions for converting heavy oil into light oil. In addition, examples include the production of lower hydrocarbons by reforming shale gas, the production of synthetic gas (a mixed gas of carbon monoxide and hydrogen) from natural gas, the production of synthetic gas using hydrocarbons as raw materials, and the production of synthetic gas from coal and components produced from coal. In addition, examples include reactions related to the production of synthetic gas from petroleum, the production of alcohols, aldehydes, carboxylic acids, ethers, alkanes, etc. from synthetic gas, and reactions for converting carbon dioxide into chemicals. In addition, examples include reactions related to the production of oxygen-containing compounds by partial oxidation of hydrocarbons, the production of unsaturated hydrocarbons by conversion of saturated hydrocarbons, and the production of liquid crystal compounds, luminescent materials, etc. by coupling between aromatic rings or aromatic rings and aliphatic rings. In addition, examples include the production of labeled compounds in which hydrogen is replaced with deuterium, polymerization reactions related to the production of oligomers and polymers from monomers containing unsaturated hydrocarbons, and inorganic reactions. The above chemical reactions can be usually caused by heating the reaction raw materials that cause the target reaction by microwave irradiation. Alternatively, the reaction raw materials can be passed through a catalyst and irradiated with microwaves to cause a chemical reaction. For example, the reaction raw materials can be supplied into the above-mentioned reaction tube, standing waves can be formed by microwave irradiation, and the reaction raw materials in the reaction tube can be heated by the maximum part of the electric field strength of the standing wave to cause a chemical reaction. Alternatively, a catalyst can be placed in the reaction tube, the reaction raw materials can be passed through the catalyst, and the reaction raw materials can be heated by the maximum part of the electric field strength of the standing wave in the same manner as above, or the catalyst can be heated to cause a chemical reaction.

The above chemical reactions themselves are publicly known, and the chemical reaction method of the present invention can be applied to a wide range of publicly known chemical reactions, except for the control of the heating state.

In the chemical reaction method of the present invention, the conditions such as reaction time, reaction temperature, reaction substrate, reaction medium, etc. may be appropriately set according to the target chemical reaction. For example, chemical reaction conditions can be appropriately set by referring to Chemistry Handbook (edited by Suzuki Shuichi and Mukaiyama Mitsuaki, Asakura Publishing, 2005), Microwave Chemical Process Technology II (edited by Takeuchi Kazuhiko and Wada Yuji, CMC Publishing, 2013), JP 2010-215677 A, JP 2011-137226 A, etc.

The microwave processing device 1 of the present invention can be configured to place the above-mentioned heated object 31 in the cavity resonator 2, and heat the heated object 31 locally or substantially entirely by the standing waves formed in the cavity resonator 2. It can also be configured to generate a chemical reaction by using it as a microwave chemical reaction device that generates a chemical reaction by heating the heated object 31. The chemical reaction generated by heating the heated object 31 may be a chemical reaction of the heated object 31 itself to generate a reaction product, or a chemical reaction may be generated by the action (typically catalytic action) of the heated heated object 31.

Next, the present invention will be specifically described based on examples, but the present invention should not be interpreted as being limited to the following examples.

[Example 1]
As an embodiment of the present invention, a microwave processing apparatus 1A shown in Fig. 1 was used. The microwave processing apparatus 1A has a microwave oscillator 4, a cavity resonator 2 for forming a standing wave of TM ₀₁₀ mode, a tube 6, and a liquid sending means 41 for sending a heated object 31 to the tube 6. The cavity resonator 2 is configured as a metallic cavity resonator having a cylindrical microwave irradiation space 2A therein. The inner diameter of this microwave irradiation space 2A is set to 248 mm so that a standing wave called TM ₀₁₀ can be formed. The inner diameter refers to the diameter of a circle that is a cross-sectional shape in a direction perpendicular to the central axis C of the cylindrical microwave irradiation space.

A tube 6 made of quartz glass or polytetrafluoroethylene (PTFE) was installed so as to penetrate along the central axis C of the microwave irradiation space 2. A liquid sending pump was attached to one side as a liquid sending means 41 so that the fluid could flow through this tube 6. On the other side of the reaction tube 6, a thermocouple (K type, diameter 0.25 mm) was attached as a thermometer 42 at a position 1 cm from the outlet 2 _OUT of the cavity resonator 2 so that the temperature of the fluid could be measured. In addition, a detection unit 12 was attached to measure the electric field intensity inside the microwave irradiation space 2A.

A semiconductor microwave oscillator capable of adjusting the frequency was used as the microwave oscillator 4. The oscillation frequency of the microwave oscillator was adjusted by controlling the signal from the detector 12 so that the frequency was such that a standing wave of _TM010 could be maintained within the cavity resonator 2.

Regarding the size of the microwave generator 4 and the cavity resonator 2, a semiconductor microwave generator (895-935 MHz, maximum output 300 W) was used that generates microwaves with a frequency in the 915 MHz band, and the cavity resonator 2 had an inner diameter of 248 mm and an irradiation length to the reaction tube 6 of 40 mm. The tube 6 used had the size and material shown in Table 1.

In this Example 1, ethylene glycol was heated at a flow rate of 100 ml/h and a microwave output of 20 W. Figure 3 shows the rate of temperature rise per microwave output when ethylene glycol was heated using the tube 6 shown in Table 1. The vertical axis of Figure 3 represents the temperature rise (ΔT/°C) obtained by subtracting the starting temperature from the reached temperature, and further represents the temperature rise divided by the microwave output. As shown in Figure 3, it was found that a tube 6 with an inner diameter of 4 mm was able to heat ethylene glycol most efficiently.

To confirm the formation of standing waves in the cavity resonator 2, a network analyzer (E5071C, manufactured by Agilent Technologies) was used to examine the waveform of S21. S21 is the microwave [transmitted wave voltage]/[incident wave voltage] (forward characteristic). When a standing wave is formed in the cavity resonator 2, S21 shows an upwardly convex waveform. Figure 4 shows the waveform of S21 when the tube 6 shown in Table 1 is used and the tube 6 is filled with ethylene glycol. Since an upwardly convex shape was shown in all tubes with inner diameters of 1 to 6 mm, it was found that a standing wave was formed and microwave heating was performed in a single mode.

[Example 2]
In Example 2, microwave heating was performed in the same manner as in Example 1, except that ethylene glycol was microwave-heated at a high flow rate. Figure 5 shows the temperature rise characteristics when ethylene glycol was microwave-heated at a flow rate higher than that of Example 1. A tube 6 with an inner diameter of 6 mm was used. The temperature reached at a microwave output of 100 W and a flow rate of 600 ml/h was 111°C, and the temperature reached at a microwave output of 300 W and a flow rate of 1800 ml/h was 129°C. The temperature fluctuation in the reached temperature was within ±2°C in both cases, and ethylene glycol could be heated even at a high flow rate using a tube 6 with an inner diameter of 6 mm.

[Comparative Example 1]
As Comparative Example 1, ethylene glycol was heated using a microwave oscillator equipped with a semiconductor element generating microwaves in the 2.45 GHz band. Microwave heating was performed in the same manner as in Example 1, except that the frequency of the microwave generator was different.

Regarding the size of the microwave oscillator and cavity resonator, a microwave oscillator that generates microwaves in the 2.45 GHz band (oscillation frequency: 2.4 to 2.6 GHz, maximum output: 100 W) was used. In addition, a cavity resonator with an inner diameter of 90 mm and an irradiation length to the tube 6 of 10 mm was used. The tube 6 used had the size and material shown in Table 1.

In this Comparative Example 1, ethylene glycol was heated at a flow rate of 100 ml/h and a microwave output of 20 W, as in Example 1. Figure 6 shows the rate of temperature rise per microwave output when ethylene glycol was heated using tube 6 in Table 1. The vertical axis of Figure 6 is the temperature rise (ΔT/°C) obtained by subtracting the starting temperature from the reached temperature, and then dividing this by the microwave output. The graph shows that the heating efficiency decreases as the inner diameter increases, and at an inner diameter of 4 mm, it is about 1/5 of that at an inner diameter of 1 mm.

As in Example 1, the waveform of S21 was examined using a network analyzer to confirm the state of standing waves formed in the cavity resonator. Figure 7 shows the waveform of S21 when the tube 6 shown in Table 1 is used and the tube 6 is filled with ethylene glycol. In the tube 6 with an inner diameter of 2 mm or less, the waveform of S21 shows an upwardly convex shape, indicating that standing waves are formed and microwave heating is performed in a single mode. However, in the tube 6 with an inner diameter of 4 mm or more, the intensity decreased to the background level (approximately -70 dB or less). In addition, the graph when a tube 6 with an inner diameter of 4 mm or more is used shows an almost flat shape, indicating that microwave heating is performed in a multimode state rather than a single mode state in which standing waves are formed.

[Example 3]
In Example 3, ion-exchanged water and N,N-dimethylacetamide, which are classified as polar solvents like ethylene glycol, were heated using the same microwave processing device 1A as in Example 1. A quartz tube 6 with an outer diameter of 8 mm and an inner diameter of 6 mm was used. FIG. 8 shows the temperature rise characteristics when ion-exchanged water (boiling point 100°C) was used as the object to be heated and heated by standing waves of microwaves in the 915 MHz band. In the case of ion-exchanged water, the temperature reached at a microwave output of 10 W was about 57°C at a flow rate of 100 ml/h, the temperature reached at a microwave output of 20 W was about 80°C, and the boiling point was reached at an output of 30 W. FIG. 9 shows the temperature rise characteristics when N,N-dimethylacetamide (boiling point 165°C) was used as the object to be heated and heated by microwaves. That is, the time changes of the temperature, incident microwave wave, reflected microwave wave, and resonant frequency are also shown. (a), (b), and (c) are the cases where the microwave output is 40 W, 60 W, and 80 W. In the case of N,N-dimethylacetamide, the temperatures reached when heated at a flow rate of 480 ml/h with microwave outputs of 40 W, 60 W, and 80 W were approximately 100°C, approximately 120°C, and approximately 150°C, respectively. Since the reflected wave was nearly 0 W and the resonance frequency changed in accordance with the temperature change, it was found that the frequency feedback control unit 11 always generated microwaves optimal for forming standing waves. As described above, it was found that any of the solvents could be heated to near the boiling point using a tube 6 with an inner diameter of 6 mm.

[Example 4]
Toluene, which is classified as a non-polar solvent, was heated using the same microwave processing device 1A as in Example 1. A quartz tube with an outer diameter of 8 mm and an inner diameter of 6 mm and a quartz tube with an outer diameter of 20 mm and an inner diameter of 18 mm were used as reaction tubes. When the microwave output was 100 W and the flow rate was 100 ml/h, it was possible to increase the temperature by 10°C or more in 2 minutes in both reaction tubes, and it was found that even non-polar solvents that are difficult to heat with microwaves can be heated.

As in Example 1, the waveform of S21 was examined using a network analyzer to confirm the state of standing wave formation in the cavity resonator. Figure 10 shows the waveform of S21 when toluene is filled in the reaction tube. Since the waveform of S21 shows an upward convex shape in both tubes 6 with an inner diameter of 6 mm and 18 mm, it was found that a standing wave was formed and microwave heating was performed in a single mode.

[Example 5]
In this embodiment, the liquid was heated by the microwave processing device 1C shown in FIG. 11. This microwave processing device 1C had the same configuration as the microwave processing device 1A, except that the liquid was not circulated in the tube. This microwave processing device was a batch-type microwave processing device consisting of a microwave oscillator (not shown), a TM ₀₁₀ cavity resonator 2, and a magnetic stirrer 51. The magnetic stirrer 51 was equipped with a stirrer 52 for stirring the liquid in the tube 6. A quartz test tube with an outer diameter of 10 mm and an inner diameter of 8 mm was used as the tube 6, and was placed along the central axis of the cavity resonator 2 to heat the liquid. An optical fiber thermometer (FL-2000 (product name) manufactured by Anritsu Meter Co., Ltd.) (not shown) was used to measure the temperature, and the temperature of the liquid at the upper surface position of the cavity resonator 2 was measured. Ion-exchanged water, 1-methyl-2-pyrrolidone (boiling point 202°C), and N,N-dimethylacetamide were used as the heating liquid. 3 ml of each was placed in a test tube and stirred with a stirrer. The height of the liquid in the test tube was 68 mm, while the irradiation height of the cavity resonator 2 was 20 mm. FIG. 12(a) shows the temperature rise characteristics of ion-exchanged water, FIG. 12(b) shows 1-methyl-2-pyrrolidone, and FIG. 12(c) shows N,N-dimethylacetamide. These temperature rise characteristics are the temperature rise characteristics when each liquid is heated with microwave outputs of 20 W, 50 W, 100 W, and 200 W. It was found that by increasing the microwave output, each liquid was heated to near the boiling point in about 20 seconds. From the above, it was found that the microwave processing device 1 (1C) of the present invention, which uses a 915 MHz band microwave with a long wavelength, can also heat tubes with a large inner diameter, and is therefore suitable for batch microwave heating using test tubes.

[Example 6]
In this example, microwave heating of a solid (powder) was performed. Using the same microwave processing device 1A as in Example 1, carbon powder was filled into a quartz tube 6 having an outer diameter of 20 mm and an inner diameter of 18 mm, and the tube was placed along the central axis C of the microwave irradiation space 2 and heated. A radiation thermometer (TMHX-CN0500 (product name) manufactured by Japan Sensor Co., Ltd.) (not shown in FIG. 1) was used to measure the temperature, and the surface temperature of the tube 6 was measured. The bulk density of the carbon powder in the tube 6 was 0.26 g/cm ^3. FIG. 13 shows the temperature rise characteristics during microwave heating. The temperature reached at a microwave output of 50 W was about 300° C.

[Comparative Example 2]
A microwave processing device equipped with a semiconductor element generating microwaves in the 2.45 GHz band, similar to that in Comparative Example 1, was used, and the tube 6 similar to that in Example 6 was used, carbon powder was filled in the tube 6, and microwave heating was performed by disposing the tube 6 in the same manner as in Example 6. The temperature rise characteristics during microwave heating are also shown in Figure 13. The reached temperature at a microwave output of 50 W was about 90°C.

To confirm the state of standing wave formation in the cavity resonator 2, the waveform of S21 was examined using a network analyzer. Figure 14 shows the waveform of S21 when the reaction tube was filled with carbon powder and heated using microwaves in the 915 MHz band. Figure 15 shows the waveform of S21 when heating was performed using microwaves in the 2.45 GHz band. In the case of microwave heating in the 915 MHz band, the waveform of S21 shows an upward convex shape, which indicates that standing waves are formed and microwave heating is performed in a single mode. On the other hand, in the case of microwave heating in the 2.45 GHz band, the intensity of S21 was reduced to the background level (approximately -70 dB or less), and microwave heating was performed in a multi-mode state rather than a single mode state in which standing waves are formed, and the heating efficiency was greatly reduced.

[Example 7]
In Example 7, S21 was measured when a reaction tube 6 filled with ethylene glycol was installed using a cavity resonator with an inner diameter (239 mm) smaller than the inner diameter of the microwave irradiation space of the cavity resonator used in Example 1. In Example 7, the same microwave processing device 1A as used in Example 1 was used, except for the inner diameter of the cavity resonator and the frequency of the microwave generated by the microwave generator 4. FIG. 16 shows the waveform of S21 measured using a network analyzer when ethylene glycol was filled in the tube 6 with each inner diameter shown in Table 1 and microwaves were irradiated. The waveform of S21 showed a waveform with an upward convex shape in all reaction tubes 6 with inner diameters of 1 to 4 mm, so that a standing wave was formed, and it was found that a single-mode standing wave was formed and microwave heating was possible even with microwaves with a frequency of 950 to 980 MHz, which is different from Example 1.

[Example 8]
In Example 8, the microwave processing apparatus 1D shown in FIG. 17 was used to perform microwave heating of ion-exchanged water. This microwave processing apparatus 1D has the same configuration as the microwave processing apparatus 1A, except that a pressure gauge 61 and an exhaust valve 62 are provided at the outlet of the reaction tube 6. That is, it is a pressurizable flow-type microwave processing apparatus consisting of a microwave oscillator 4, a _TM010 mode cavity resonator 2, a pressure gauge 61, and an exhaust valve 62. A quartz reaction tube having an outer diameter of 6 mm and an inner diameter of 4 mm was used as the reaction tube 6, and was installed along the central axis C of the cavity resonator 2. A radiation thermometer (not shown) was used to measure the temperature, and the surface temperature of the reaction tube 6 was measured. The liquid was delivered at 30 ml/h (residence time: about 60 seconds) using a double plunger pump, and heating was performed while maintaining the microwave output at a constant value of 90 W. The pressure inside the reaction tube during heating was maintained in the range of 0.5 to 0.8 MPa by adjusting the exhaust valve.

Figure 18 shows the temperature rise characteristics when ion-exchanged water (boiling point 100°C) is heated. The temperature was raised to approximately 150°C, but the ion-exchanged water did not boil. From the above, it was found that the configuration of this microwave processing device 1D is a device configuration that can heat liquids to above their boiling point.

[Example 9]
In Example 9, microwave heating synthesis of zeolite was carried out as an example of a chemical reaction using the microwave processing device 1D shown in FIG. 17. The reaction tube 6 and the radiation thermometer (not shown) had the same device configuration as in Example 8. The raw material solution was prepared by dissolving sodium aluminate, a 30 mass% colloidal silica solution, and sodium hydroxide in pure water, mixing them so that Na:Al:Si:H ₂ O = 4:1:1:125, and then stirring at room temperature for 24 hours. Thereafter, the raw material solution was fed to the liquid feeding means 41 at a flow rate of 15 ml/h (residence time: about 120 seconds) using a double plunger pump, and microwave heating was performed with the set temperature set to 140°C. The pressure inside the reaction tube during heating was maintained in the range of 0.5 to 0.8 MPa by adjusting the exhaust pressure valve 62. The precipitate was collected by centrifuging the solution after heating, and was repeatedly washed by centrifugation several times using pure water. The precipitate was then dried and particle analysis was performed. For particle analysis, an X-ray diffraction device (SmartLab manufactured by Rigaku Corporation) was used.

Figure 19 shows the temperature rise characteristics when the zeolite raw material solution is heated. The temperature ranges from 130 to 150°C, with the set temperature being 140°C, and it was found that the zeolite raw material solution can be heated in the temperature range of about 151°C, the boiling point of water at a pressure of 0.5 MPa. Figure 20 shows the X-ray diffraction pattern of the synthesized product. Peaks indicating the synthesis of LTA-type zeolite were confirmed.

1, 1A, 1B, 1C, 1D Microwave processing device 2, 21, 22, 23 Cavity resonator 2A Microwave irradiation space 2 _OUT outlet 3 Microwave supply port 4 Microwave generator 5 Antenna 6 Tube, reaction tube 7 Cable 11 Control unit (feedback control unit)
12 Detection unit 31 Processing object (heated object)
41 Liquid delivery means 42 Thermometer 51 Magnetic stirrer 52 Stirrer 61 Pressure gauge 62 Pressure relief valve C Central shaft

Claims (10)

A microwave processing apparatus for irradiating a microwave into a cavity resonator to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) in the cavity resonator,
The microwave has a frequency of 895 to 935 MHz;
A tube is disposed along a portion where the electric field strength of the standing wave is maximized, and an object to be treated is placed in the tube ;
A microwave processing apparatus, wherein the maximum length of the object to be processed is 3 mm or more and 20 mm or less in a direction perpendicular to the direction in which the electric field strength of the standing wave is constant.
(However, this does not include the following water quality analyzers, activated gas reaction devices, and light source devices.
[Water quality analyzer]
A water quality analysis device having a reaction tube made of a material that transmits microwaves within a microwave irradiation space, and a heating medium fixed to a position within the reaction tube where microwave energy is concentrated, and which supplies sample water to the reaction tube, and analyzes the gas obtained by contacting the heating medium heated by microwaves with the sample water, or the liquid obtained by cooling the gas, to measure the carbon content in the sample water.
[Activated gas reaction device]
An activated gas reaction apparatus comprising an activation chamber, a means for supplying a raw material gas to the activation chamber, a microwave power generator for activating the raw material gas supplied to the activation chamber, and a reaction chamber into which the activated gas is transported and supplied to the outside of the activation chamber.
[Light source device]
A light source device comprising: a microwave resonator having an internal space for generating a standing wave of microwaves; a microwave supplying means for supplying microwaves to the internal space of the microwave resonator ; and a gas cell in which a medium is enclosed and disposed in the internal space of the microwave resonator, the light source device generating light by exciting the medium in the gas cell with the standing wave of microwaves generated in the internal space of the microwave resonator, and outputting the generated light to the outside of the microwave resonator through a light outlet hole provided in the microwave resonator. 2. The microwave processing apparatus according to claim 1, wherein the cavity resonator forming the standing wave of the TM _0n0 mode has a dimension of a microwave irradiation space of the cavity resonator along a direction in which the electric field strength of the standing wave is constant, the dimension being equal to or less than 1/2 of the wavelength of the microwave. 3. The microwave processing apparatus according to claim 1, further comprising a feedback control section for matching a frequency of the microwave supplied into the cavity resonator with a frequency of a standing wave formed in the cavity resonator . 4. The microwave processing apparatus according to claim 1, further comprising a loop antenna or a monopole antenna for supplying microwaves to a microwave irradiation space in the cavity resonator. The microwave processing apparatus according to claim 1 , which is a chemical reaction apparatus that heats the object to be processed by microwaves to cause a chemical reaction. A plurality of the cavity resonators are arranged in series,
an object to be processed is disposed through the plurality of cavity resonators in a direction in which the plurality of cavity resonators are connected in series and along a portion where an electric field intensity of a standing wave formed in the plurality of cavity resonators is maximized;
6. The microwave processing apparatus according to claim 1, further comprising a microwave generator for separately supplying microwaves to each of said plurality of cavity resonators. A microwave processing method for irradiating a microwave into a cavity resonator to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) in the cavity resonator and processing an object to be processed by using the standing wave, comprising the steps of:
The microwave has a frequency of 895 to 935 MHz;
A tube is arranged along a portion where the electric field strength of the standing wave is maximized, and the object to be processed is placed in the tube ;
A microwave processing method in which the maximum length of the object to be processed is 3 mm or more and 20 mm or less in a direction perpendicular to the direction in which the electric field strength of the standing wave is constant.
(However, this does not include the microwave processing method in the water quality analyzer, activated gas reaction device, and light source device described below.
[Water quality analyzer]
A water quality analysis device having a reaction tube made of a material that transmits microwaves within a microwave irradiation space, and a heating medium fixed to a position within the reaction tube where microwave energy is concentrated, and which supplies sample water to the reaction tube, and analyzes the gas obtained by contacting the heating medium heated by microwaves with the sample water, or the liquid obtained by cooling the gas, to measure the carbon content in the sample water.
[Activated gas reaction device]
An activated gas reaction apparatus comprising an activation chamber, a means for supplying a raw material gas to the activation chamber, a microwave power generator for activating the raw material gas supplied to the activation chamber, and a reaction chamber into which the activated gas is transported and supplied to the outside of the activation chamber.
[Light source device]
A light source device comprising: a microwave resonator having an internal space for generating a standing wave of microwaves; a microwave supplying means for supplying microwaves to the internal space of the microwave resonator ; and a gas cell in which a medium is enclosed and disposed in the internal space of the microwave resonator, the light source device generating light by exciting the medium in the gas cell with the standing wave of microwaves generated in the internal space of the microwave resonator, and outputting the generated light to the outside of the microwave resonator through a light outlet hole provided in the microwave resonator. 8. The microwave processing method according to claim 7 , wherein the temperature of the object to be processed is controlled in the processing of the object to be processed. 9. The microwave processing method according to claim 7 , wherein a reaction involving the object to be processed is promoted or stopped by controlling a temperature of the object to be processed. A chemical reaction method comprising: irradiating a microwave into a cavity resonator to form a single-mode standing wave of TM _0n0 (n is an integer of 1 or more) in the cavity resonator; and heating an object to be treated by the standing wave,
The microwave has a frequency of 895 to 935 MHz;
a tube is arranged along a portion where the electric field strength of the standing wave is maximized, the object to be treated is placed in the tube , and the object to be treated is heated to cause a chemical reaction;
A chemical reaction method in which the maximum length of the object to be processed is 3 mm or more and 20 mm or less in a direction perpendicular to the direction in which the electric field strength of the standing wave is constant.
(However, this does not include the following water quality analyzers, activated gas reaction devices, and chemical reaction methods using microwave processing in light source devices.
[Water quality analyzer]
A water quality analysis device having a reaction tube made of a material that transmits microwaves within a microwave irradiation space, and a heating medium fixed to a position within the reaction tube where microwave energy is concentrated, and which supplies sample water to the reaction tube, and analyzes the gas obtained by contacting the heating medium heated by microwaves with the sample water, or the liquid obtained by cooling the gas, to measure the carbon content in the sample water.
[Activated gas reaction device]
An activated gas reaction apparatus comprising an activation chamber, a means for supplying a raw material gas to the activation chamber, a microwave power generator for activating the raw material gas supplied to the activation chamber, and a reaction chamber into which the activated gas is transported and supplied to the outside of the activation chamber.
[Light source device]
A light source device comprising: a microwave resonator having an internal space for generating a standing wave of microwaves; a microwave supplying means for supplying microwaves to the internal space of the microwave resonator ; and a gas cell in which a medium is enclosed and disposed in the internal space of the microwave resonator, the light source device generating light by exciting the medium in the gas cell with the standing wave of microwaves generated in the internal space of the microwave resonator, and outputting the generated light to the outside of the microwave resonator through a light outlet hole provided in the microwave resonator.

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