CN114425289A

CN114425289A - Microwave reactor

Info

Publication number: CN114425289A
Application number: CN202011184455.5A
Authority: CN
Inventors: 汤文
Original assignee: Huanggang Anruinong Environmental Protection Technology Co ltd
Current assignee: Huanggang Anruinong Environmental Protection Technology Co ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2022-05-03

Abstract

The invention discloses a microwave reactor, which comprises a reaction device, a transmission device, a feed device and a supporting device, wherein the transmission device is arranged on the reaction device; the reaction device comprises a cubic hollow metal cavity, a cubic hollow metal feed inlet which is arranged on one side surface of the metal cavity and extends outwards and is not sealed at two ends, a discharge outlet which is consistent in shape and size is correspondingly arranged on the other side surface of the metal cavity, and wave-absorbing materials are attached to the inner walls of the feed inlet and the discharge outlet; the transmission device includes: the conveying belt penetrates through the metal cavity, the feeding hole and the discharging hole and is in contact with the bottom of the metal cavity, the lower portion of the conveying belt is supported by a plurality of rotatable supporting rollers which are evenly arranged on the lower side of the metal cavity, a heat dissipation plate is arranged in the metal cavity, the conveying belt is driven by the power rollers, and the power rollers are driven by the speed-adjustable motor.

Description

Microwave reactor

Technical Field

The invention belongs to the field of microwave energy application devices, and particularly relates to a microwave reactor.

Background

Aiming at the application requirement of a large-scale microwave reactor, a non-resonant microwave reaction cavity is provided, and the volume of the reaction cavity is greatly increased; the principle is that through reasonable design, direct power feeding is carried out in a large-scale reaction cavity to generate a plurality of field modes, so that fields in the cavity are concentrated in a certain specific area, and meanwhile, a guide pipe, a conveyor belt and the like are placed at the specific area to enable an object to be processed to continuously pass through the field concentrated area at a constant speed, so that the purpose of heating or improving the chemical reaction rate is achieved; but still has the defects of non-centralized field, poor reaction uniformity, low reaction efficiency, high energy consumption, difficult solid processing and the like. For example, in patent document CN104667849A, a serpentine waveguide feed is used, which can only continuously process gas and liquid samples, and the serpentine waveguide feed is not uniform, the radiation at the back end of the waveguide becomes weaker, and the end needs a device to absorb the energy not radiated, which is wasted.

According to the application requirements of the existing large-scale industrial microwave reactor, an efficient, uniform and quick large-scale continuous microwave reactor is required to be combined with the existing production line so as to achieve the purposes of reducing energy consumption, improving efficiency and ensuring processing consistency. Based on the technical scheme, the invention is innovatively improved aiming at the feeding mode and the field distribution of the large-scale non-resonant microwave reactor so as to further improve the reaction effect of the reactor.

Disclosure of Invention

The invention aims to provide a continuous transmission type quasi-diffraction wave-free microwave reactor aiming at the defects of the prior art, the mode that the existing waveguide port is directly fed into a microwave irradiation reactant is changed into the mode that the existing waveguide port is fed into a multi-feed port to generate the diffraction wave-free irradiation reactant, so that the reaction efficiency is improved, the reaction speed is accelerated, the reaction uniformity is improved, the energy is saved, and the continuous transmission type quasi-diffraction wave-free microwave reactor is combined with a continuous transmission type production line and is applied to large-scale industrial production.

In order to achieve the purpose, the invention adopts the technical scheme that:

a microwave reactor comprises a reaction device, a transmission device, a feed device and a support device; the reaction device comprises a cubic hollow metal cavity, a cubic hollow metal feed inlet which is arranged on one side surface of the metal cavity and extends outwards and is not sealed at two ends, a discharge outlet which is consistent in shape and size is correspondingly arranged on the other side surface of the metal cavity, and wave-absorbing materials are attached to the inner walls of the feed inlet and the discharge outlet; the transmission device includes: the conveying belt penetrates through the metal cavity, the feeding hole and the discharging hole and is in contact with the bottom of the metal cavity, the lower portion of the conveying belt is supported by a plurality of rotatable supporting rollers which are evenly arranged on the lower side of the metal cavity, a heat dissipation plate is arranged in the metal cavity, the conveying belt is driven by the power rollers, and the power rollers are driven by the speed-adjustable motor.

As a further aspect of the present invention, a power feeding apparatus includes: the device comprises a radiator, a feed waveguide, a power distribution and phase shifter, a coaxial transmission line and a microwave source; the power distribution and phase shifter consists of a coaxial waveguide-to-waveguide power divider and a waveguide power divider phase shifter; the microwave source is connected with the input end of the power distribution and phase shifter through a coaxial transmission line, the output end of the power distribution and phase shifter is connected with a plurality of feed waveguides, the feed waveguides penetrate through the metal cavity to be connected with the radiator, the radiator is a cubic metal block and is positioned at the middle lower position of the back of the metal cavity, a rectangular radiation opening which is in butt joint with the feed waveguides and has the same size is formed in the radiator, and thin quartz glass is attached to the radiation opening to prevent materials from falling into the radiation opening.

As a further aspect of the present invention, a supporting device includes: a load-bearing table; the reaction device, the transmission device and the feed device are arranged on the bearing workbench; the non-slip mat is arranged below the bearing workbench and attached to the ground.

The invention relates to a microwave reactor, which radiates quasi-diffraction-free electromagnetic waves by radiators in reasonable arrangement to act on processed materials from the side surface, and because the diffraction-free waves avoid the diffraction effect when the electromagnetic waves propagate in the space, the field intensity is not attenuated along with the propagation distance, the microwave reactor has the advantages of concentrated energy, strong penetrating power, uniform action and high efficiency, greatly improves the total volume of the action of an electric field and reactants, improves the reaction efficiency, reduces the energy consumption and saves the cost. The quasi-diffraction-free electromagnetic wave requires that the radiation port surface field obeys the amplitude-phase distribution of a Bezier function, namely the amplitude and the phase of the emergent field of each rectangular radiation port of the radiator (31) are determined according to the distance from the center of the radiator, and the quasi-diffraction-free electromagnetic wave is realized by adjusting the power distribution and the phase shifter (33); the concrete distribution is as follows:

E(ρ)＝E0J0(kBρ)

wherein, E0 is the feed electric field intensity of the central radiation opening; j0 is a zero order Bessel function; KB is a radial beam and can be used for regulating the penetration depth of the diffraction-free wave, and the smaller the KB value is, the larger the penetration depth is, and the height of the metal cavity (11) and the side length of the radiator (31) are required to be determined. Thus, the feeding strength and phase of the other 24 radiation ports are determined by substituting the distance rho between the center of the radiation port and the center of the radiator (31) into the formula. At the moment, the wave emitted from the radiator is quasi-diffraction-free wave, the influence of diffraction expansion of electromagnetic waves in space transmission is avoided, and the quasi-diffraction-free electromagnetic wave has the advantages of energy concentration, uniform action, adjustable action depth and high efficiency.

In the transverse comparison with the reactant of the long-strip coal block with the side length of the cross section of 100mm, compared with the prior continuous direct feed type microwave reactor, the reaction efficiency of the quasi-diffraction-free microwave reactor is improved by more than 2.4 times, and meanwhile, the good reaction uniformity can be kept in the reactant; inside the reactants, the maximum and minimum values of specific absorption rate (i.e. the efficiency of absorption of microwave energy by a volume of the body) differ by only 9%; this shows that all reactants can be reacted well and efficiently, and there is no situation that part of reactants in the traditional reactor are reacted insufficiently and the other part is reacted excessively, which indirectly reduces the requirement for the output power of the microwave source, reduces the energy consumption and saves the cost.

In conclusion, the beneficial effects of the invention are as follows:

the invention is different from the existing direct feed type, the feed structure generates diffraction-free beams to directly irradiate reaction materials, the influence of diffraction expansion in the process of electromagnetic wave propagation is avoided, the electromagnetic energy is concentrated, the effect is uniform, the action depth is adjustable, the reaction efficiency is high, and the energy is saved. The invention adopts a non-resonant structure, the shape and the volume of the cavity are not limited by a field mode and a resonance point, a power division phase-shifting network externally arranged in the reaction cavity is adopted, the structure is compact, the space of the reaction cavity is not occupied, the field distribution effect in the cavity is not influenced, the invention has unique advantages in the processing aspect of large solid materials, can be combined with a continuous flow water type production line and is applied to large-scale industrial production. The feeding and discharging port is opened, the absorption cavity paved with the wave-absorbing material is utilized to inhibit microwave leakage, the open structure enables a sample to continuously and directly enter, microwave leakage is extremely small, and the microwave-absorbing device is safe and reliable.

Drawings

FIG. 1 is a front view of a microwave reactor of the present invention;

FIG. 2 is a side view of a microwave reactor of the present invention except for the roller and motor portions;

fig. 3 is a top view of the radiator of the invention;

in the figure: 11. the microwave oven comprises a metal cavity, 12 parts of a feeding hole, 13 parts of a discharging hole, 21 parts of a conveyor belt, 22 parts of a speed-adjustable motor and a power roller, 23 parts of a supporting roller, 31 parts of a radiator, 32 parts of a feed waveguide, 33 parts of a power distribution and phase shifter, 34 parts of a coaxial transmission line, 35 parts of a microwave source, 4 parts of a load-bearing workbench and 5 parts of the microwave oven. Non-slip mat, 6. heat sink.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Examples

The embodiment provides a microwave reactor, which comprises a reaction device, a transmission device, a feeding device and a supporting device; the reaction device comprises a cubic hollow metal cavity 11, a cubic hollow metal feed inlet 12 which is arranged on one end face of the metal cavity and extends outwards and is not sealed at two ends, a discharge outlet 13 which is consistent in shape and size is correspondingly arranged on the other end face, and thin wave-absorbing materials are attached to the inner walls of the feed inlet 12 and the discharge outlet 13 to prevent microwave leakage; the transmission device includes: the conveyor belt passes through the metal cavity 11, a heat dissipation plate 6 is arranged in the metal cavity 11 and can help the machine to dissipate heat, the feed inlet 12 and the discharge outlet 13 are contacted with the bottom of the metal cavity, the lower part of the conveyor belt is supported by a plurality of rotatable supporting rollers uniformly arranged on the lower side of the metal cavity, the conveyor belt is driven by the power rollers, and the power rollers are driven by the adjustable-speed motor; a radiator 31, a feed waveguide 32, a power distribution and phase shifter 33, a coaxial transmission line 34, and a microwave source 35; the power distribution and phase shifter 33 is composed of a coaxial waveguide-to-waveguide power divider and a waveguide power divider phase shifter; the microwave source is connected with the input end of the power distribution and phase shifter through a coaxial transmission line, the output end of the power distribution and phase shifter is connected with a plurality of feed waveguides, the feed waveguides penetrate through the metal cavity 11 to be connected with the radiator, the radiator is a solid cubic metal block and is positioned at the middle lower part of the side surface of the metal cavity 11, rectangular radiation ports which are butted with the feed waveguides and have the same size are formed in the radiator, and thin quartz glass is attached to the radiation ports to prevent materials from falling into the radiation ports; the supporting device comprises: a load-bearing table 4; the reaction device, the transmission device and the feed device are arranged on the bearing workbench; the non-slip mat 5 is arranged below the bearing workbench 4, and the non-slip mat 5 is attached to the ground.

The invention is a microwave reactor, which radiates quasi-diffraction-free electromagnetic waves by radiators with reasonable layout to act on processing materials, has the advantages of energy concentration, uniform effect at different depths and high efficiency, greatly improves the total volume of the action of an electric field and reactants, improves the reaction efficiency, reduces the energy consumption and saves the cost. Quasi-non-diffracting electromagnetic waves require a distribution of the radiation port surface field obeying the Bezier function, i.e. the amplitude and phase of the exit field of each rectangular radiation port of the radiator 31 are determined according to their distance from the center of the radiator by adjusting the power distribution and phase shifter 33.

The frequency of the microwave source 35 should be different according to the physicochemical characteristics of the processed object, and a proper microwave frequency band is found, and generally, the lower frequency microwave energy keeps better penetrability so as to improve the reaction uniformity; the size of the metal cavity (11) is determined according to the size of an object to be processed in an application scene; the cross section shapes of the feed inlet (12) and the discharge outlet (13) are determined according to the shape and the volume of the processed object, and can be rectangular, circular, semicircular and the like, and the flat-plate type rubber wave-absorbing material of RAT-2G type is pasted on the inner wall of the cross section shapes to prevent residual microwave energy from leaking, so that the length of the feed inlet and the discharge outlet can be determined according to the output power of a microwave source and the maximum radiation standard of national 1mW/cm 2. The overall length of the metal cavity (11) is more than 1m, so that a good reaction effect can be obtained. The speed-adjustable motor (23) controls the conveying speed of the processed object, and the speed-adjustable motor and the output power of the microwave source (35) jointly control the degree and the speed of the microwave reaction. The power division ratio and the output phase of the power distribution and phase shifter (33) are uniquely determined by a parameter kb, and the kb is determined according to the width W of the cross section of the metal cavity (11) and the side length L of the radiator (31):

wherein lambda is the free space wavelength of the electromagnetic wave, the feed waveguide (32) is a BJ26 type standard rectangular waveguide, and the length is more than 0.5 times lambda; the radiator (31) is provided with radiation ports which are equal in number, shape and size and correspond to the feed waveguides (32), and the transverse and longitudinal distances between the centers of the radiation ports are lambda.

The power distribution and phase shifter (33) consists of a CTW-5 type coaxial rotary waveguide one-to-five power divider (331) and 5 MOW-5 type waveguide one-to-five power divider phase shifters (332), and finally 1-to-25 coaxial rotary waveguide power distribution and phase shifter is realized; the coaxial transmission line (34) is first connected to a coaxial waveguide five-to-one power divider (331), and the ports from top to bottom shown in fig. 3 are P1-P5, respectively, and the power division ratios thereof are shown in the following table. The 5 output ports of the power divider (331) are respectively connected to a one-to-five power dividing phase shifter (332), and the output amplitude and phase of the power dividing phase shifter (332) are set as described above and calculated by the formula E (ρ) -E0J 0(kB ρ).

The specific dimensions of this example are: the length of the outer conductor (11) is 1.5m, the width is 1m, the height is 0.6m, and the material is copper; the width of the conveyor belt (21) is 0.6m, the thickness is 4mm, and the conveyor belt is made of rubber; the microwave source (33) adopts a 2.4GHz-2.5GHz frequency-adjustable amplitude-modulated microwave source, and the coaxial transmission line (34) adopts a 50-16 type hard coaxial line; the length of the feed inlet (12) and the discharge outlet (13) is 0.8m, the width is 0.6m, the height is 0.3m, the thickness is 2mm, the material copper is attached to the inner wall of the feed inlet and the discharge outlet, the RAT-2G type flat plate type rubber wave-absorbing material is attached to the inner wall of the feed inlet and the discharge outlet, the vertical incidence reflectivity of the wave-absorbing material is-15 dB to-20 dB, the leakage power density is 0.21mW/cm2 when the output power of the microwave source (33) is 3kW, and the national standard is met. The radiator (31) is 612mm long, 612mm wide and 1mm high, the material copper is evenly distributed with 25 rectangular feed holes with the length of 86.36mm and the width of 43.18mm, the distance between adjacent feed holes is 122.45mm, and the radiator (31) is covered with quartz glass with the thickness of 7 mm. The feed waveguide (32) is a BJ26 standard rectangular waveguide, 62mm long.

Further, the above technical solution can be changed as follows: (1) the microwave power supply normally works at the microwave frequency of 915MHz or 2.45GHz for civil industry, and can meet more requirements by changing the whole size and the parameter kb in a feed function to adapt to microwaves with different frequencies; (2) the shapes of the feed inlet (12) and the discharge outlet (13) can be changed on the cross section to adapt to the shapes of processed objects, such as rectangle, circle, ellipse and the like, and the lengths are reasonably set to ensure that the electromagnetic leakage of the material inlet and the material outlet after the wave absorbing material is attached is less than 1mW/cm 2; (3) the conveyor belt 21 can be made of various materials, such as a rubber conveyor belt or a polymer conveyor belt which takes nylon and aramid as frameworks, and the materials need to have lower loss and thinner thickness; (4) the shape, size and number of the rectangular feeding ports on the radiator (31) can be changed into a circle, a square and the like.

The invention adopts non-diffraction wave to irradiate the target reactant and has the advantages of high electric field intensity, concentrated electromagnetic energy, uniform action, adjustable action depth and high reaction efficiency.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

Claims

1. A microwave reactor comprises a reaction device, a transmission device, a feed device and a support device; the device is characterized in that the reaction device comprises a cubic hollow metal cavity, a cubic hollow metal feed inlet which is arranged on one side surface of the metal cavity and extends outwards and is not sealed at two ends, a discharge outlet which is consistent in shape and size is correspondingly arranged on the other side surface of the metal cavity, and wave-absorbing materials are attached to the inner walls of the feed inlet and the discharge outlet; the transmission device includes: the conveying belt penetrates through the metal cavity, the feeding hole and the discharging hole and is in contact with the bottom of the metal cavity, the lower portion of the conveying belt is supported by a plurality of rotatable supporting rollers which are evenly arranged on the lower side of the metal cavity, a heat dissipation plate is arranged in the metal cavity, the conveying belt is driven by the power rollers, and the power rollers are driven by the speed-adjustable motor.

2. A microwave reactor according to claim 1, wherein the feed means comprises: the device comprises a radiator, a feed waveguide, a power distribution and phase shifter, a coaxial transmission line and a microwave source; the power distribution and phase shifter consists of a coaxial waveguide-to-waveguide power divider and a waveguide power divider phase shifter; the microwave source is connected with the input end of the power distribution and phase shifter through a coaxial transmission line, the output end of the power distribution and phase shifter is connected with a plurality of feed waveguides, the feed waveguides penetrate through the metal cavity to be connected with the radiator, the radiator is a cubic metal block and is positioned at the middle lower position of the back of the metal cavity, a rectangular radiation opening which is in butt joint with the feed waveguides and has the same size is formed in the radiator, and thin quartz glass is attached to the radiation opening to prevent materials from falling into the radiation opening.

3. A microwave reactor according to claim 1, wherein the support means comprises: a load-bearing table; the reaction device, the transmission device and the feed device are arranged on the bearing workbench; the non-slip mat is arranged below the bearing workbench and attached to the ground.