CN216501452U

CN216501452U - Dangerous solid useless processing apparatus of high-power microwave plasma

Info

Publication number: CN216501452U
Application number: CN202121935037.5U
Authority: CN
Inventors: 朱铧丞; 杨阳; 黄卡玛
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2020-10-05
Filing date: 2021-08-17
Publication date: 2022-05-13
Anticipated expiration: 2031-08-17

Abstract

The utility model relates to the field of plasma equipment, in particular to a high-power microwave plasma dangerous solid waste treatment device, which solves the problem of dangerous solid waste treatment caused by small size and low power of plasma in the prior art. The utility model comprises a dangerous solid waste crushing and grinding device, a powder input device, a plasma generating device, a cracked gas processing device and a microwave cavity; the microwave generating device is arranged around the microwave cavity; the number of the microwave generating devices is not less than three; the microwave cavity is a hollow cylindrical multi-cavity. The utility model realizes the treatment of the dangerous solid waste plasma with large power and large size by using the high-power microwave plasma device as the dangerous solid waste treatment device, arranging a plurality of microwave generating devices with different distances and staggered heights and uniformly and intensively constraining electromagnetic waves at the central position of the quartz tube; the utility model has simple structure, high treatment efficiency and low cost, and meets the requirement of industrialization on a large scale.

Description

Dangerous solid useless processing apparatus of high-power microwave plasma

Technical Field

The utility model relates to the field of plasma equipment, in particular to a high-power microwave plasma dangerous solid waste treatment device.

Background

Dangerous solid wastes, namely dangerous solid wastes, are various in types, and municipal wastes, waste biomass, medical wastes, polychlorinated biphenyl, incineration fly ash, sludge, electronic wastes, waste asbestos and the like, so that the universality of dangerous solid waste disposal technology is limited, and the dangerous solid waste treatment process is complicated and variable.

The domestic and foreign solid waste treatment method mainly comprises landfill and incineration, and the landfill method has the problems of large floor area, secondary pollution and the like; although the incineration method can realize the harmlessness, reduction and recycling of the garbage, the garbage is easy to generate a large amount of dioxin and furan during combustion, and the dioxin is one of the most toxic organic matters in the world at present, mainly pollutes air, soil and water bodies, and further pollutes animals, plants and aquatic organisms; people are mainly injured by air, drinking water and food; dioxin can cause serious skin injury diseases, has strong carcinogenic and teratogenic effects, and has fatal toxicity to animals at a very small dose.

The plasma treatment had the following characteristics: 1) the plasma has extremely high energy density, temperature and extremely fast reaction time, can thoroughly decompose various organic matters into micromolecular combustible gas, has small occupied area, can achieve large treatment capacity, and can realize fast start and stop; 2) the applicable range of the plasma is very wide, and the plasma comprises various wastes such as solid, liquid, gas and the like; 3) because fuel combustion does not exist, the heat source is generated without oxidant, and compared with the conventional heat treatment process, the method has the advantages of much less smoke generated, easy treatment and low cost.

However, in the plasma treatment process, the gas flow rate is small, and the influence of the plasma on the entering waste is large, so that the defects of difficult arc striking, easy arc extinguishing and the like exist. The speed and temperature spatial distribution in the torch are greatly influenced by the volume flow change of the material carrying gas, the volume flow change of the reaction gas also has certain influence on the plasma temperature, and the arc can be extinguished due to the overhigh volume flow of the reaction gas.

And the following defects exist in the treatment process, which causes the blockage of the production quantity production:

1. most microwave plasmas realize plasmas in a waveguide compression or waveguide mode, the diameter of the plasmas is small, the diameter of the plasmas is only 3-4cm under 2450MHz, the microwave action area is short, and the maximum diameter of the plasmas is 5cm under the action of microwaves;

2. the microwave plasma generator forms plasma under a single mold cavity, so that the area of a plasma region is small, and the energy utilization rate is low;

3. the microwave plasma generator cannot radiate heat to the reaction cavity through self airflow due to low ventilation volume, so that high external heat radiation capacity is required. The device cannot realize large-scale gas treatment or large-scale plasma treatment application.

There is a need for a new hazardous solid waste treatment device that can solve the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model provides a high-power microwave plasma dangerous solid waste treatment device, which solves the problem of dangerous solid waste treatment caused by small size and low power of plasma in the prior art.

The technical scheme of the utility model is realized as follows: a high-power microwave plasma dangerous solid waste treatment device comprises a dangerous solid waste crushing and grinding device, a powder input device, a plasma generation device and a cracked gas treatment device; the plasma generating device comprises a plasma ignition device, a microwave generating device, a waveguide, a reaction cavity for processing gas into plasma, and a gas inlet for introducing powder into the reaction cavity; the microwave cavity is sleeved outside the reaction cavity; the axis position of the microwave cavity is superposed with the axis of the reaction cavity; the microwave generating device is arranged around the microwave cavity in a staggered manner at different distances through the waveguide; the number of the microwave generating devices is not less than three; the microwave cavity is a hollow cylindrical multi-cavity; the ignition device and the gas inlet are arranged at the lower end of the reaction cavity; the pyrolysis gas treatment device further comprises a heat energy circulation, and the heat energy circulation is connected with the dangerous solid waste crushing and grinding device and the powder input device.

Furthermore, the electromagnetic waves at the center of the reaction cavity are uniformly and intensively distributed; the microwave cavity and the waveguide positions are simulated and optimized by a finite element method.

Further, the microwave cavity is a metallic microwave cavity for concentrating microwave energy.

Furthermore, the reaction cavity is made of a material with small electromagnetic loss and high temperature resistance.

Further, the reaction chamber is a quartz tube, a cylindrical metal tube is further sleeved outside the quartz tube, the diameter of the metal tube is larger than that of the quartz tube, and the height of the metal tube is consistent with that of the quartz tube.

Preferably, the reaction chambers may be cascaded, in particular with the upper end of a quartz tube being coupled to the lower end of another quartz tube.

Further, the microwave generators are uniformly distributed at the longitudinal section of the quartz tube.

Further, the microwave generating device and the waveguide can be three groups, four groups or five groups.

The utility model discloses a high-power microwave plasma dangerous solid waste treatment device, which is characterized in that a high-power microwave plasma device is used as a dangerous solid waste treatment device, a plurality of microwave generating devices are arranged at different distances and in a staggered manner, and electromagnetic waves are uniformly and intensively bound at the central position of a quartz tube, so that the high-power large-size dangerous solid waste plasma treatment is realized; the utility model has simple structure, high treatment efficiency and low cost, and meets the requirement of industrialization on a large scale; the utility model can be cascaded to realize effective superposition of power.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1: the system module of the utility model is shown schematically;

FIG. 2: the structure schematic diagram of the four microwave sources;

FIG. 3: a simulation schematic diagram of four paths of microwave sources;

FIG. 4: a simulation schematic diagram of three paths of microwave sources;

FIG. 5: a simulation schematic diagram of five paths of microwave sources;

FIG. 6: a cascade schematic of the utility model;

wherein: 10. a feed inlet; 20. a hazardous solid waste crushing and grinding device; 30. a powder input device; 40. a plasma generating device; 41. a microwave cavity; 42. a waveguide; 43. a microwave generating device; 44. an air inlet; 45. A plasma ignition device; 46. a reaction chamber; 48. a cylindrical metal tube; 50. a cracked gas treatment unit; 60. a harmless discharge port; 61. and (4) circulating the heat energy.

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.

As shown in fig. 1, the schematic structural diagram of the present invention discloses a high-power microwave plasma hazardous solid waste treatment device, which comprises a hazardous solid waste crushing and grinding device 20, a powder input device 30, a plasma generation device 40, and a cracked gas treatment device 50; the plasma generating device 40 comprises a plasma ignition device 45, a microwave generating device 43, a waveguide 42, a reaction cavity 46 for processing gas into plasma, and an air inlet 44 for introducing powder into the reaction cavity 46; the microwave cavity 41 is sleeved outside the reaction cavity 46; the axle center position of the microwave cavity 41 is superposed with the axle center of the reaction cavity 46; the microwave generating devices 43 are arranged around the microwave cavity 41 in a staggered manner at different distances through the waveguide 42; the number of the microwave generating devices 43 is not less than three; the microwave cavity 41 is a hollow cylindrical multi-cavity; the ignition device and the air inlet 44 are arranged at the lower end of the reaction cavity 46; the pyrolysis gas treatment device 50 further comprises a heat energy circulation 61, and the heat energy circulation 61 is connected with the dangerous solid waste crushing and grinding device 20 and the powder input device 30.

Further, the electromagnetic waves are uniformly and intensively distributed at the center of the reaction cavity 46; the microwave cavity 41 and waveguide 42 positions are simulated and optimized by a finite element method.

And (3) simulation process:

a. variables in the optimization process, such as the Z-axis coordinates of the four waveguides 42 and the radius of the metal cylindrical cavity, are defined, and the electric field distribution can be optimized by changing the numerical values;

b. constructing a geometric model: four metal rectangular BJ26 waveguides 42, metal cylindrical cavities, metal tubes and quartz tubes;

c. creating a definition: assigning actual meaning to each domain and boundary;

d. adding materials: giving each cavity and boundary different material properties;

e. defining physical field, adding four microwave source feed-in ports;

f. setting a parametric scan: writing the variation range of the optimizable variable, calculating all permutation and combination through comsol, and selecting the parameter value when the electric field distribution is optimized;

g. and (4) dividing a grid, running analysis, and obtaining an optimal result according to the electric field distribution diagram and the S11 value.

Further, the microwave cavity 41 is a metallic microwave cavity 41 for concentrating microwave energy. Further, the reaction chamber 46 is made of a material with low electromagnetic loss and high temperature resistance. Further, the reaction chamber 46 is a quartz tube, and a cylindrical metal tube 48 is further sleeved outside the quartz tube, wherein the diameter of the metal tube is larger than that of the quartz tube, and the height of the metal tube is consistent with that of the quartz tube.

Preferably, the reaction chambers 46 may be cascaded, in particular with the upper end of a quartz tube being coupled to the lower end of another quartz tube. The plasma generating device 40 is composed of a plurality of cavities, microwaves are input into the microwave cavity 41 through the rectangular waveguide 42, the plasmas are restrained in the quartz tube reaction cavity 46 and are isolated from the microwave cavity 41 through the quartz tube, electromagnetic waves are restrained from radiating outwards from an opening caused by the quartz tube through the metal tube isolation cavity, microwave energy is concentrated, stability of a plasma torch is facilitated, the microwave energy can be efficiently converted into the microwave plasmas through the multi-cavity structural design, the device is cascaded, and the two devices are cascaded in a mode that the quartz tubes are connected with one another, so that effective superposition of power is achieved.

As shown in the schematic block diagram of the system of FIG. 1, in the using process, dangerous solid wastes are fed into a crusher from a feed inlet 10 to be stirred and crushed, and then are placed in a solid waste silo, and are secondarily ground into powder by a grinder, and then enter a plasma generating device 40 through an air duct. Under 2450MHz, the microwave power can reach 4-12kW, microwave energy is fed into the multiple mold cavities, the microwave energy is focused in the multiple mold cavities through calculation design, and high-power microwave plasma is generated through an ignition device. The treatment reaction zone is a quartz tube and is isolated from the microwave cavity 41, combustion-supporting gas hydrogen is introduced into the quartz tube from a combustion-supporting port, the treatment reaction is carried out in an ultrahigh-temperature reaction environment, harmless CO2, H2O, acid gas and some solid particles are generated, the dust concentration is high, and microorganisms in the garbage are completely killed; the treatment gas is discharged from a discharge channel, the treatment gas firstly passes through a deacidification device, the acidic gas is purified and eliminated by adopting a conventional dry and wet scrubbing system, then is rapidly cooled and quenched by a quench tower, and then is adsorbed by active carbon to remove components generating peculiar smell, and finally, particles in the gas are removed by a vortex dust removal device; the high-temperature flue gas generated after complete combustion is discharged into the environment after passing through a flue gas purification system, the waste heat of the high-temperature flue gas is recycled and used for power generation, urban heating and the like, and the vitrified substances formed by high-temperature melting treatment of the slag generated by pyrolysis can be extracted to be made into cement or pure metal substances, so that the nontoxic and harmless treatment of the slag is realized, and the purified up-to-standard waste gas is finally discharged into the atmosphere.

The plasma generating devices 40 can be three, four or five groups. Plasma electron density, electron temperature and gas temperature all increase with increasing microwave input power. The increase of the microwave power can accelerate the collision reaction in the plasma, thereby leading to the increase of the electron density generation speed and providing more heat sources for heating the gas. The multiple inputs greatly improve the quality of the plasma torch within the reaction chamber 46.

Four microwave sources:

the utility model consists of four BJ26 waveguides 42, a metal cylindrical cavity, a metal tube and a quartz tube. The four rectangular waveguides 42 are embedded on the wall of the metal cylinder, the quartz tube penetrates through the center of the cylinder cavity, and the metal tube covers the outer layer of the quartz tube to separate the cylinder cavity from the quartz tube; the method adopts the finite element method-based multi-physical field simulation software COMSOL5.4 to carry out geometric modeling and creation definition, endows each domain and boundary with actual significance, sets material properties, defines related physical fields and divides grids, and carries out simulation and numerical analysis.

In the four-path plasma structure, microwaves are input from the four waveguide 42 ports with certain power, so that the microwave power is effectively increased, the electron density, the electron temperature and the gas temperature of the plasma are increased along with the increase of the microwave input power, and the collision reaction in the plasma is accelerated, so that the electron density generation speed is accelerated, and more heat sources are provided for heating the gas.

After microwave is input by the ports of the four waveguides 42 with certain power, an electric field distribution diagram in the cylindrical cavity is observed, and the geometric dimension of the cylindrical cavity and the corresponding positions of the four waveguides 42 and the bottom of the cylindrical cavity are continuously changed: specifically, the method comprises the following steps:

when the coordinates z of the four microwave sources are 0, that is, four microwave sources are parallel, the four microwave sources are located in the middle of the microwave cavity 41 to feed microwaves, and at this time, the electric field distribution in the microwave cavity 41 cannot be concentrated in the quartz tube in the microwave cavity 41, so that the four microwave sources are distributed in a staggered manner, and the purpose of concentrating the electric field at the center of the circle is achieved.

When three microwave sources are located on the same Z plane, two microwave sources are located on the same Z plane, and none of the microwave sources are located on the same Z plane, the Z-axis coordinates of the four microwave sources are respectively set as Z1, Z2, Z3 and Z4, a parameterized scanning list is added, a Z coordinate dislocation range is given, the optimal electric field distribution is selected through different arrangement combinations, and when none of the four microwave sources is parallel, the electric field is favorably concentrated at the circle center.

Increasing power, and determining the optimal electric field distribution as shown by the graph by simulating different staggered distances of the four microwave sources; furthermore, when the z-axis coordinate of each microwave source is fixed and unchanged, the maximum electric field intensity and the best focusing effect can be obtained by simulating electric field patterns under different metal cylindrical cavity radiuses.

And then constantly optimize electric field focusing effect, form powerful microwave plasma torch, finally confirm that cylinder cavity radius is 115mm, four metal rectangle BJ26 wave guides 42 are wide for 84.6mm, high for 43.2mm, the depth is 205mm apart from cylinder cavity outer most ring distance, four metal rectangle wave guides 42 rotate 90 degrees and distribute in proper order in the cylinder cavity wall, its distance apart from the top is respectively: 18.4mm, 33.4mm, 28.4mm and 23.4mm, and the heights are staggered.

As shown in the simulation diagram of the first embodiment of fig. 2, the temperature in the quartz tube is concentrated and uniform.

Three and five microwave sources:

on the basis of four microwave sources, the structures of the plasma generators of three microwave sources and five microwave sources are respectively, and the design and the size of the rest parts of the device are not changed except the number and the positions of the waveguides 42; the simulation optimization process is the same as the steps of the plasma generators of the four microwave sources, the comsol is used for carrying out optimization simulation analysis on the plasma generators of the three microwave sources and the five microwave sources, and after the optimal optimization parameters are respectively determined, the optimal electric field distribution diagram is obtained; the maximum electric field of the plasma generator of the three-way microwave source is 2.12 x 10³V/m, the plasma generator of five microwave sources is difficult to focus the highest electric field energy at the center of a circle, while the plasma generator of four microwave sources has the maximum electric field of 2.49-10³V/m, and perfectly concentrates electric field energy in a certain range.

Plasma electron density, electron temperature and gas temperature all increase with increasing microwave input power. The increase of the microwave power can accelerate the collision reaction in the plasma, thereby leading the electron density generation speed to be accelerated, simultaneously providing more heat sources for heating the gas, and greatly improving the quality of the plasma torch in the reaction cavity 46 by multi-path input.

The utility model discloses a high-power microwave plasma dangerous solid waste treatment device, which is characterized in that a plurality of microwave generating devices 43 are arranged at different distances and in staggered heights to serve as dangerous solid waste treatment devices, and electromagnetic waves are uniformly and intensively bound to the central position of a quartz tube, so that the high-power large-size dangerous solid waste plasma treatment is realized; the utility model has simple structure, high treatment efficiency and low cost, and meets the requirement of industrialization on a large scale; the utility model can be cascaded to realize effective superposition of power.

It is understood that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the utility model, and it is intended to cover in the appended claims all such changes and modifications.

Claims

1. A high-power microwave plasma dangerous solid waste treatment device comprises a dangerous solid waste crushing and grinding device, a powder input device, a plasma generation device and a cracked gas treatment device; the plasma generating device comprises a plasma ignition device, a microwave generating device, a waveguide, a reaction cavity for processing gas into plasma, and a gas inlet for introducing powder into the reaction cavity; the method is characterized in that:

the microwave cavity is sleeved outside the reaction cavity; the axis position of the microwave cavity is superposed with the axis of the reaction cavity; the microwave generating device is arranged around the microwave cavity in a staggered manner at different distances through the waveguide;

the number of the microwave generating devices is not less than three;

the microwave cavity is a hollow cylindrical multi-cavity;

the ignition device and the gas inlet are arranged at the lower end of the reaction cavity;

the pyrolysis gas treatment device further comprises a heat energy circulation, and the heat energy circulation is connected with the dangerous solid waste crushing and grinding device and the powder input device.

2. The high-power microwave plasma dangerous solid waste treatment device according to claim 1, wherein: the electromagnetic waves at the center of the reaction cavity are uniformly and intensively distributed.

3. The high-power microwave plasma dangerous solid waste treatment device according to claim 2, wherein: the microwave cavity is a metallic microwave cavity for concentrating microwave energy.

4. The high-power microwave plasma dangerous solid waste treatment device according to claim 3, wherein: the reaction cavity is made of a material with small electromagnetic loss and high temperature resistance.

5. The high-power microwave plasma dangerous solid waste treatment device according to claim 4, wherein: the reaction chamber is a quartz tube, a cylindrical metal tube is further sleeved outside the quartz tube, the diameter of the metal tube is larger than that of the quartz tube, and the height of the metal tube is consistent with that of the quartz tube.

6. The high-power microwave plasma dangerous solid waste treatment device according to claim 5, wherein: the reaction chambers can be cascaded, and particularly, the upper end of one quartz tube is connected with the lower end of another quartz tube.

7. The high power microwave plasma hazardous solid waste treatment device according to any one of claims 1-6, characterized in that: the microwave generating devices are uniformly distributed at the longitudinal section of the quartz tube.

8. The high-power microwave plasma dangerous solid waste treatment device according to claim 7, wherein: the microwave generating device and the waveguide can be three groups, four groups or five groups.