阅读说明：本技术 一种有机污染土壤微波修复装备及其修复方法 (Microwave remediation equipment for organic contaminated soil and remediation method thereof ) 是由 张优 王恒钦 孟静娟 孙广银 袁彦辉 宋庆赟 郝辉锋 张超越 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种有机污染土壤微波修复装备及其修复方法,包括微波土壤修复装置和尾气微波催化燃烧装置；所述微波土壤修复装置包括上料传输带、连接在所述上料传输带出口的物料输送机、设置在所述物料输送机后端的微波反应腔、固定连接在所述微波反应腔出气口的集气管以及连接在所述集气管出口的尾气微波催化燃烧装置。本申请是一种连续型的微波土壤修复装备,可以方便地验证微波对石油污染土壤在不同工艺参数下的修复效果。微波土壤修复装置集成度高,不仅可以控制微波功率、传输带转速和微波辐照时间,还可以调节污染土壤的含水量和土壤进料厚度,以便本发明修复方法达到更好的土壤修复效果。(The invention discloses microwave remediation equipment and a remediation method for organic contaminated soil, wherein the microwave remediation equipment comprises a microwave soil remediation device and a tail gas microwave catalytic combustion device; the microwave soil remediation device comprises a feeding transmission belt, a material conveyor connected to an outlet of the feeding transmission belt, a microwave reaction cavity arranged at the rear end of the material conveyor, a gas collecting pipe fixedly connected to a gas outlet of the microwave reaction cavity, and a tail gas microwave catalytic combustion device connected to an outlet of the gas collecting pipe. The continuous microwave soil remediation equipment can conveniently verify the remediation effect of the microwave on the petroleum-polluted soil under different process parameters. The microwave soil remediation device has high integration level, can control microwave power, transmission belt rotation speed and microwave irradiation time, and can adjust the water content and soil feeding thickness of the polluted soil, so that the remediation method of the invention achieves better soil remediation effect.)

1. The microwave remediation equipment for organic contaminated soil is characterized in that: comprises a microwave soil remediation device and a tail gas microwave catalytic combustion device;

the microwave soil remediation device comprises a feeding conveyor belt (1), a material conveyor (2) connected to an outlet of the feeding conveyor belt (1), a microwave reaction chamber (4) arranged at the rear end of the material conveyor (2), a gas collecting pipe (5) fixedly connected to a gas outlet of the microwave reaction chamber (4), and a tail gas microwave catalytic combustion device (6) connected to an outlet of the gas collecting pipe (5);

the microwave soil remediation device also comprises an output conveyor belt (7) connected to the tail end of the microwave reaction cavity (4) and a homogenizer (8) arranged between the outlet of the material conveyor (2) and the microwave reaction cavity (4); the front end of the microwave reaction cavity (4) is provided with a moisture regulator (3);

the material conveyor (2) comprises a driving motor (21), a driving conveying roller (22), a driven conveying roller (23), a material conveying belt (24) and a supporting frame (25);

the material conveying belt (24) is sleeved on the driving conveying roller (22) and the driven conveying roller (23); the output shaft of the driving motor (21) is fixedly connected to the driving conveying roller (22);

the driving conveying roller (22), the driven conveying roller (23), the moisture regulator (3) and the homogenizer (8) are all fixedly connected to the support frame (25);

the microwave reaction cavity (4) is arranged at the upper end of the material conveying belt (24).

2. The microwave remediation equipment for organic contaminated soil as claimed in claim 1, wherein:

the microwave reaction cavity (4) comprises a reaction cavity body (41), a gas collecting pipe connecting pipe (42) arranged at the center of the upper part of the reaction cavity body (41), a hopper-shaped recovery cavity (43) sleeved on the tail gas recovery pipe and a first magnetron (44) fixedly connected to the lower end of the gas collecting pipe connecting pipe (42);

the material conveying belt (24) is arranged at the lower end of the first magnetron (44);

the front end and the rear end of the reaction cavity (41) are both provided with microwave suppressors (45); the lower end of the microwave suppressor (45) is fixedly connected with a temperature measuring probe (46);

the gas collecting pipe connecting pipe (42) is communicated with the gas collecting pipe (5);

the temperature measuring probe (46) is arranged at the upper end of the material conveying belt (24).

3. The microwave remediation equipment for organic contaminated soil as claimed in claim 2, wherein:

the microwave reaction cavity (4) also comprises a furnace door (49) arranged on one side surface of the reaction cavity (41), an observation window arranged on the furnace door (49), a dense metal shielding layer (47) arranged on the observation window and a choke groove (48) arranged on the periphery of the reaction cavity (41);

the choke groove (48) is tightly connected with the furnace door (49).

4. The microwave remediation equipment for organic contaminated soil as claimed in claim 2, wherein:

the first magnetron (44) has a frequency of 2.45 Hz.

5. The microwave remediation equipment for organic contaminated soil as claimed in claim 1, wherein:

the tail gas microwave catalytic combustion device comprises a microwave catalytic combustion reaction cavity (51) communicated with the gas collecting pipe (5), a second magnetron (52) arranged at the upper part of the microwave catalytic combustion reaction cavity (51), a waveguide pipe (53) connected with the second magnetron (52) and a heat exchanger (54) arranged at the lower part of the microwave catalytic combustion reaction cavity (51);

a tail gas circular shell is arranged at the periphery of the microwave catalytic combustion reaction cavity (51) and the heat exchanger (54); a microwave control system (56) is arranged at the upper part of the tail gas round shell;

transparent ceramic tubes are arranged on the inner walls of the periphery of the microwave catalytic combustion reaction cavity (51);

and metal baffles (58) are arranged at two ends of the ceramic tube.

6. The microwave remediation equipment for organic contaminated soil as claimed in claim 5, wherein:

the tail gas microwave catalytic combustion device also comprises a thermocouple (57) which is vertically inserted into the microwave catalytic combustion reaction cavity (51).

7. The microwave remediation equipment for organic contaminated soil as claimed in claim 5, wherein:

the tail gas microwave catalytic combustion device also comprises a circulating water cooling system (55);

and the circulating water cooling system (55) is connected with the heat exchanger (54) to form cold and hot water circulation.

8. The microwave remediation equipment for organic contaminated soil as claimed in claim 1, wherein:

the homogenizer (8) comprises a fixed frame (81) fixedly connected with the support frame (25), a connecting baffle plate (82) fixedly connected with the fixed frame (81), and equalizing teeth (83) arranged below the connecting baffle plate (82).

9. The microwave remediation method for organic contaminated soil according to any one of claims 1 to 8, wherein:

firstly, lifting soil to a certain height along a feeding conveying belt (1);

thirdly, performing microwave irradiation on the soil on the lifting path through microwaves generated by the microwave reaction cavity (4);

thirdly, the speed of the material conveying belt (24) is controlled by controlling the output speed of the driving motor (21) to adjust the feeding speed of the polluted soil;

thirdly, regulating the moisture content of the polluted soil through a moisture regulator (3);

thirdly, adjusting the feeding thickness of the soil entering the material conveying belt (24) of the microwave reaction cavity (4) through a homogenizer (8);

in addition, a thermocouple (57) was introduced for real-time monitoring of the change in temperature of the contaminated soil in the microwave field.

10. The microwave remediation method of organic contaminated soil according to any one of claims 9, wherein:

the using conditions are that the microwave power is 540-720W, the microwave irradiation time is 15-25 min, the thickness of the soil layer is 3-5 cm, and the water content of the soil is 13% -19%.

Technical Field

The invention relates to the field of soil and underground water remediation, in particular to microwave remediation equipment for organic contaminated soil and a remediation method thereof.

Background

The soil combined pollution forms are various and can be divided into the following types according to the types of pollutants: (1) organic composite pollution, which is formed by two or more organic pollutants coexisting in soil; (2) inorganic composite pollution refers to a soil environment pollution phenomenon formed by two or more inorganic pollutants acting simultaneously; (3) organic-inorganic composite pollution, and an environmental pollution phenomenon that organic pollutants and inorganic pollutants simultaneously exist and interact in the environment.

Under a heavy metal/organic matter combined pollution system, different types of organic matters and heavy metals can generate interaction in soil, so that the remediation and treatment of the soil heavy metal/organic matter combined pollution under the same condition are more difficult. In addition, the comprehensive toxicity of the composite pollution to the soil ecological environment is stronger, and the human health is seriously threatened. However, the current heavy metal/organic matter combined pollution is usually combined by adopting a single or simple physical or chemical remediation technology, and the problems of secondary pollution caused by excessive use of remediation agents and easy soil residue are solved. The soil pollution condition is complex, no matter physical remediation, chemical remediation or biological remediation, certain defects exist, how to better combine various remediation technologies and screen efficient remediation agents, and breakthrough progress is made in the aspect of remediation engineering application of the composite contaminated site, so that the problem which needs to be solved at present is solved urgently.

The microwave remediation technology is to heat the contaminated soil by using microwaves as a heat source, so that soil pollutants can be volatilized, decomposed or fixed, and the purpose of soil remediation is achieved. Microwaves can not only treat VOCs and SVOCs, but also non-volatile substances such as heavy metals. According to different repairing objects, the microwave repairing can be divided into organic matter polluted soil repairing and heavy metal polluted soil repairing. The existing microwave repair technology has the defects of large heat loss, low purification efficiency, high purification cost and the like.

At present, the research on the microwave remediation of the contaminated soil mainly focuses on microwave treatment equipment and factors influencing the pollutant removal efficiency, and most of the research is limited to laboratory scale research, but the research on the interaction influence among the factors and pilot scale research is still few. Soil remediation commonly used in China is equipped with: the integrated contaminated soil remediation technology equipment, the combined contaminated soil remediation technology equipment, the vehicle-mounted in-situ injection equipment, the contaminated soil and underground water high-pressure rotary spraying injection equipment, the Finland Arabic soil remediation equipment, the Finland Arabic screening crushing bucket and the like are mostly based on international introduction, and after the introduction, key parameters such as stirring speed, soil temperature change trend and the like are often researched by adopting laboratory equipment. Because the soil texture and the pollution condition of the composite pollution site are complex and changeable, the existing in-situ remediation technical equipment for the soil has the characteristics of small application range, strict soil texture requirement, serious corrosion and uneven stirring and mixing of remediation agents and the soil.

Disclosure of Invention

The invention aims to provide microwave remediation equipment and a remediation method for organic contaminated soil, which are convenient to operate and can conveniently verify the remediation effect of microwave on petroleum contaminated soil under different process parameters in order to avoid the problems.

The technical scheme adopted by the invention is as follows:

an organic contaminated soil microwave remediation device comprises a microwave soil remediation device and a tail gas microwave catalytic combustion device;

the microwave soil remediation device comprises a feeding conveying belt, a material conveyor connected with an outlet of the feeding conveying belt, a microwave reaction cavity arranged at the rear end of the material conveyor, a gas collecting pipe fixedly connected with a gas outlet of the microwave reaction cavity, and a tail gas microwave catalytic combustion device connected with an outlet of the gas collecting pipe;

the microwave soil remediation device also comprises an output conveyor belt connected to the tail end of the microwave reaction cavity and a homogenizer arranged between the outlet of the material conveyor and the microwave reaction cavity; the front end of the microwave reaction cavity is provided with a moisture regulator;

the material conveyor comprises a driving motor, a driving conveying roller, a driven conveying roller, a material conveying belt and a supporting frame;

the material conveying belt is sleeved on the driving conveying roller and the driven conveying roller; the output shaft of the driving motor is fixedly connected to the driving conveying roller;

the driving conveying roller, the driven conveying roller, the moisture regulator and the homogenizer are all fixedly connected to the support frame;

the microwave reaction cavity is arranged at the upper end of the material conveying belt.

Further:

the microwave reaction cavity comprises a reaction cavity body, a gas collecting pipe connecting pipe arranged at the central position of the upper part of the reaction cavity body, a bucket-shaped recovery cavity sleeved on the tail gas recovery pipe and a first magnetron fixedly connected to the lower end of the gas collecting pipe connecting pipe;

the material conveying belt is arranged at the lower end of the first magnetron;

the front end and the rear end of the reaction cavity are both provided with microwave suppressors; the lower end of the microwave suppressor is fixedly connected with a temperature measuring probe;

the gas collecting pipe connecting pipe is communicated with the gas collecting pipe;

the temperature probe is arranged at the upper end of the material conveying belt.

Further:

the microwave reaction cavity also comprises a furnace door arranged on one side surface of the reaction cavity, an observation window arranged on the furnace door, a dense metal shielding layer arranged on the observation window and a choke groove arranged on the periphery of the reaction cavity;

the choke groove is tightly connected with the furnace door.

Further:

the frequency of the magnetron is 2.45 Hz.

Further:

the tail gas microwave catalytic combustion device comprises a microwave catalytic combustion reaction cavity communicated with the gas collecting pipe, a second magnetron arranged at the upper part of the microwave catalytic combustion reaction cavity, a waveguide connected with the second magnetron and a heat exchanger arranged at the lower part of the microwave catalytic combustion reaction cavity;

a tail gas circular shell is arranged at the periphery of the microwave catalytic combustion reaction cavity and the heat exchanger; a microwave control system is arranged at the upper part of the tail gas round shell;

transparent ceramic tubes are arranged on the inner walls around the microwave catalytic combustion reaction cavity;

and metal baffles are arranged at two ends of the ceramic tube.

Further:

the tail gas microwave catalytic combustion device also comprises a thermocouple vertically inserted into the microwave catalytic combustion reaction cavity.

Further:

the tail gas microwave catalytic combustion device also comprises a circulating water cooling system;

and the circulating water cooling system is connected with the heat exchanger to form cold and hot water circulation.

Further:

the homogenizer comprises a supporting frame homogenizer fixing frame, a connecting baffle plate and pressure equalizing teeth, wherein the supporting frame homogenizer fixing frame is fixedly connected with the supporting frame homogenizer, the connecting baffle plate is fixedly connected to the fixing frame, and the pressure equalizing teeth are arranged below the connecting baffle plate.

Further: a microwave remediation method of organic contaminated soil,

firstly, lifting soil to a certain height along a feeding conveying belt;

thirdly, performing microwave irradiation on the soil on the lifting path through microwaves generated by the microwave reaction cavity;

thirdly, the feeding speed of the polluted soil is adjusted by controlling the output speed of the driving motor to control the speed of the material conveying belt;

thirdly, regulating the moisture content of the polluted soil through a moisture regulator;

thirdly, adjusting the feeding thickness of the soil entering the material conveying belt of the microwave reaction cavity through a homogenizer;

in addition, thermocouples were introduced for monitoring in real time the change in temperature of the contaminated soil in the microwave field.

Further:

the using conditions are that the microwave power is 540-720W, the microwave irradiation time is 15-25 min, the thickness of the soil layer is 3-5 cm, and the water content of the soil is 13% -19%.

Compared with the prior art, the invention has the following beneficial effects:

1. the continuous microwave soil remediation equipment can conveniently verify the remediation effect of the microwave on the petroleum-polluted soil under different process parameters. The microwave soil remediation device is high in integration level, not only can control microwave power, transmission band rotating speed and microwave irradiation time, but also can adjust the water content and the soil feeding thickness of polluted soil, so that a better soil remediation effect is achieved.

2. The microwave has the penetrating property, so that the soil can be heated inside and outside simultaneously without heat conduction, and the heating speed is very high. Meanwhile, because the soil is heated inside and outside simultaneously, the temperature difference between the inside and the outside of the material is small, the heating is ensured to be uniform, the drying speed of the soil with the water content below 30 percent can be shortened by hundreds of times, and meanwhile, the soil is not influenced by the irregular shape of the soil blocks. Compared with the traditional heating mode, the microwave irradiation has the characteristics of uniform heating, high speed, timely control, sensitive reaction, strong field, high temperature, strong penetrating power, cleanness, sanitation, no pollution and the like.

3. The utility model provides a be equipped with close mesh metal shielding layer on the observation window of microwave reaction chamber furnace gate, can effective impedance microwave, all set up choke groove structure around the furnace gate with the impedance from the microwave that the crack was revealed, the door body can reflect most microwave back to the furnace chamber with the tight combination of furnace chamber front bezel together, the microwave of a small part leakage is reflected in the choke groove of the door body to can be in the choke groove reflection consumption. A trace amount of microwave leaking from the choke groove can be absorbed by the door seal, effectively preventing microwave radiation from leaking from the door gap.

4. The thickness is piled up to the soil layer that pollutes soil on can adjusting the conveyer belt that gets into the microwave reaction chamber to the installation of homogenizer to can make soil evenly distributed more. Improving the microwave repairing effect.

5. The oven door of the microwave reaction cavity is provided with the safety interlock, the system can not normally run under the condition of not closing the oven door, the microwave reaction cavity is effectively prevented from starting to work under the condition that the oven door is open, and the safety of human bodies and the surrounding environment is ensured.

6. The application uses the microwave catalytic combustion device to carry out catalytic combustion treatment on the tail gas after microwave thermal desorption of the polluted soil so as to achieve the purpose of thoroughly purifying pollutants in the soil. The catalytic combustion technology has the advantages of simple equipment, easy control, low reaction temperature, no secondary pollution and the like, is suitable for treating volatile organic compounds with high concentration, low gas amount and no recycling value, and improves the environmental protection performance of equipment so that the repairing process is pollution-free.

7. Microwave heating directly transfers microwave energy to the catalyst through an independent microwave device without heating rod materials, and realizes the conversion of electromagnetic energy on the surface of the catalyst into heat energy. The microwave heating has the advantages of directional heating, fast temperature rise and fall, uniform heating, high mineralization rate and the like, and the microwave device has high automation degree and continuously adjustable power.

8. This application uses the microwave inhibitor to install at microwave reaction cavity both ends, prevents that microwave soil repair system from revealing from the reaction cavity at the in-process microwave of operation, and the radiation of production is released and is endangered the health in the environment, improves the environmental protection security of this equipment.

Drawings

FIG. 1 is a schematic structural diagram of the present invention;

FIG. 2 is a schematic structural view of the material conveyor of the present invention;

FIG. 3 is a schematic view of the internal structure of the microwave reaction chamber according to the present invention;

FIG. 4 is a schematic diagram of the external structure of the microwave reaction chamber according to the present invention;

FIG. 5 is a schematic view showing the structure of a choke groove according to the present invention;

FIG. 6 is a schematic structural diagram of the tail gas microwave catalytic combustion device of the present invention;

FIG. 7 is a schematic structural diagram of a homogenizer according to the present invention;

FIG. 8 shows the temperature change of the soil under different microwave powers;

FIG. 9 shows the variation of Nap removal rate at different microwave powers;

FIG. 10 shows the temperature change of the soil under different water contents;

FIG. 11 shows the change of the Nap removal rate under different water contents;

FIG. 12 shows the temperature change of soil under different soil layer thicknesses;

FIG. 13 shows the variation of Nap removal rate for different soil layer thicknesses.

In the drawings: 1, a feeding conveying belt; 2 a material conveyor; 21 driving a motor; 22 an active conveying roller; 23 driven conveying roller; 24 a material conveyor belt; 25, supporting frames; 3, a moisture regulator; 4, a microwave reaction cavity; 41 a reaction chamber; 42 gas collecting pipe connecting pipe; 43 hopper-shaped recovery cavities; 44 a first magnetron; 45 microwave suppressors; 46 temperature measuring probe; 47 dense mesh metal shielding layer; 48 a choke groove; 481 door seal; 49 a furnace door; 5, a gas collecting pipe; 51, a microwave catalytic combustion reaction cavity; 52 a second magnetron; 53 a waveguide; 54 heat exchanger; 55 circulating water cooling system; 56 a microwave control system; 57 a thermocouple; 58 a metal baffle; 6 tail gas microwave catalytic combustion device; 7, outputting the conveyor belt; 8, a homogenizer; 81 a fixing frame; 82 connecting the baffle plate; 83 grading teeth.

Detailed Description

The technical solution of the present patent will be described in further detail with reference to the following embodiments.

It is to be understood that the terms "height," "width," "upper," "lower," "left," "right," and the like, as used herein, refer to an orientation or positional relationship illustrated in the drawings of the present application for convenience in describing and simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered a representation of the present invention.

The microwave remediation technology is to heat the contaminated soil by using microwaves as a heat source, so that soil pollutants can be volatilized, decomposed or fixed, and the purpose of soil remediation is achieved. Microwaves can not only treat volatile VOCs and SVOCs, but also non-volatile substances such as heavy metals. According to different repairing objects, the microwave repairing can be divided into organic matter polluted soil repairing and heavy metal polluted soil repairing. Through simulated petroleum-contaminated soil and field, naphthalene in 16 PAHs (polycyclic aromatic hydrocarbons) optimally controlled by USEPA (ultra-stable oxygen gas) is taken as a target pollutant of the petroleum-contaminated soil, and the microwave remediation of the petroleum-contaminated soil simulated by the naphthalene is taken as a core content to carry out research: the single-factor experiment researches the influence of 4 factors on naphthalene removal efficiency in the microwave soil remediation process, namely changes the microwave power, the processing time, the soil layer thickness and the soil water content in a system, each group of experiments are provided with 3 groups of parallel experiments, and the optimal value range of each influence factor is determined.

And (2) taking a 20 g Nap contaminated soil sample, wherein the residual quantity of Nap in the soil is reduced along with the increase of the microwave irradiation time, the removal rate of Nap in the soil is increased along with the increase of the microwave irradiation time, when the microwave heating time is prolonged to 20-30 min, the content of the residual Nap in the soil is not obviously changed, and the change curve of the removal rate of Nap along with the time tends to be smooth, so that the microwave heating time is continuously prolonged after the microwave irradiation time reaches a certain degree, and the removal effect of Nap is not obviously improved. The analysis reason is that when the microwave heating time is short, the microwave energy absorbed by the soil is less, the conversion rate of heat energy is low, the soil can not rise to a higher temperature, the soil moisture evaporation is insufficient in a short time, and the Nap desorption is insufficient. After the microwave heating time is increased to 30 min, the Nap removal rate is slightly reduced, and the analysis reason is that a part of Nap pollutants can be re-adsorbed onto soil particles due to the overlong microwave irradiation time, so that the Nap content in the soil is slightly increased. And comprehensively considering economic factors and pollutant removal efficiency, and determining the optimal range of the microwave irradiation time to be 15-25 min.

The microwave heating characteristics of contaminated soil are related to the electric field strength of the applied microwave field. The change of the microwave output power can change the microwave field intensity, thereby influencing the heating effect of the polluted soil in the microwave field and further influencing the removal effect of petroleum substances in the polluted soil. In the experiment, 20 g of Nap contaminated soil is taken, the initial concentration of Nap in the soil is 325.24 mg.kg < -1 >, the water content of the soil is 16 percent, the microwave heating time is 20 min, and the influence effects of different microwave powers on the concentration of the residual Nap in the soil and the removal rate of the Nap are examined.

Experimental results show that when the microwave power is too small, the field intensity of a microwave field is weak, the contaminated soil cannot obtain enough energy, the heating rate of the contaminated soil is influenced, the soil cannot reach a high-temperature state in a short time, and the contaminated soil can reach the ideal removal temperature of pollutants under the lower microwave power, so that the soil can obtain enough energy by prolonging the microwave heating time. In addition, although the increase of the microwave power is beneficial to the desorption of pollutants in the soil, the medium for absorbing the microwaves can be heated up at a very high speed under the condition of excessive microwave output power, and the heat conduction of the wave absorbing medium can be influenced. In addition, the application of higher radiation power may result in reduced controllability of the reaction process, and the excess of microwaves causes not only unnecessary damage to the microwave reactor but also waste of energy. Therefore, the range of microwave power is 540-720W.

The change of the water content of the polluted soil changes the conductivity and the dielectric constant of the soil sample, water has higher dielectric loss factor, and the relative difference of the water content among the soil samples causes the difference of reaction temperature, thereby influencing the removal efficiency of pollutants. The initial concentration of Nap in the contaminated soil is 325.24 mg.kg < -1 >, the contaminated soil with different series of water contents is prepared and is respectively 3%, 5%, 7%, 10%, 13%, 16%, 19% and 22%, the addition amount of GAC in the soil sample is 5 wt%, and the influence of different soil water contents on the residual concentration of Nap in the contaminated soil and the removal rate of Nap is examined.

The removal rate of Nap increases and then decreases along with the increase of the soil moisture content. The water content of the soil is increased from 3 percent to 16 percent, the concentration of the Nap remained in the soil is reduced from 81.20 mg.kg < -1 > to 19.84 mg.kg < -1 >, and the removal rate of the Nap is increased from 75.0 percent to 93.8 percent. The removal rate of Nap reached a maximum of 93.9% when the soil moisture content was 16%, at which time the residual Nap in the soil was 19.84 mg/kg-1. The relative dielectric constant of the soil is 2.6 at room temperature, the dielectric loss factor is 0.02, the relative dielectric constant of the water is 77, the dielectric loss factor is 13, compared with the soil, the water has a very high dielectric loss factor value, and the effective dielectric loss factor value of a soil system can be increased by the water, so that the microwave heating capacity of the soil is improved. Therefore, under the same microwave power and irradiation time, the soil contains a certain amount of water, so that the temperature rise rate of the soil can be effectively improved, and the soil can rapidly enter high temperature. On the other hand, since Nap belongs to SVOCs and has a volatile property, Nap volatilizes along with the evaporation of water, and therefore, the increase of the soil moisture content contributes to the removal of Nap in the soil. However, when the water content of the contaminated soil is more than 16%, the removal rate of Nap in the soil tends to decrease, and experimental data show that the water content is increased to 22%, the removal rate of Nap in the soil is decreased by 4.5% compared with the removal rate under the condition of the soil water content of 16%, and the concentration of the residual Nap in the soil is 34.58 mg kg < -1 >. The analysis reason is that the specific heat capacity of water is larger than that of soil, and the specific heat capacity of the soil mixture system is increased due to the increase of the soil moisture content, so that the microwave heating temperature-rising capacity of the soil system is weakened. And when the water content of the soil reaches more than 20%, the soil is in a slurry shape and is sticky in texture, the permeability of the soil is obviously reduced, and the migration of soil pollutants is hindered. On the other hand, the soil moisture content is too high and will restrain the soil and heat up, because more microwave energy can be absorbed to moisture, the evaporation of moisture can consume a large amount of heat energy and lead to the soil can't reach higher temperature, is unfavorable for desorption of soil pollutant, and this is unanimous with the research result of liu xianbao etc.. However, as water has a high dielectric constant, the residual water in the soil can still rapidly absorb the wave and raise the temperature along with the evaporation of the water in the microwave heating process, so that the removal efficiency of the Nap after the microwave irradiation for 20 min is still higher than that of the polluted soil with the water content within 10%. Therefore, the optimal water content of the polluted soil in the microwave thermal remediation process is 13% -19%.

Different soil amounts mean different volumes and heights of soil in the reactor, the studied soil layer thickness series is 1, 2, 3, 4, 5 and 6 cm, the soil mass is about 10, 20, 30, 40, 50 and 60 g, 700W microwave power is provided, irradiation is carried out for 20 min, the initial concentration of Nap in the soil is 325.24 mg.kg < -1 >, the soil water content is 16 percent, the proportion of GAC to the soil is kept unchanged and is 5 percent by weight in the experimental process, and the influence of different soil layer thicknesses on the residual Nap content in the polluted soil and the Nap removal rate are examined.

The removal rate of Nap is gradually reduced when the thickness of the soil layer is increased. The thickness of the soil layer is increased to 4 cm from 1 cm, the concentration of the residual Nap in the polluted soil is reduced to 11.38 mg kg < -1 > from 60.49 mg kg < -1 >, the removal rate of the Nap in the soil is increased to 96.5% from 81.4%, the thickness of the soil layer is 1-3 cm, and the increase range of the removal rate of the Nap is relatively large. When the thickness of the soil layer is increased from 4 cm to 6 cm, the concentration of the residual Nap in the soil is increased to 27.75 mg-kg < -1 >, the removal rate of Nap is reduced from 96.5 percent to 91.5 percent, and the removal rate of Nap is reduced by 5.0 percent. When the soil thickness is 4 cm, the removal rate of Nap reaches the maximum value, and the concentration of the residual Nap in the soil under the condition is 11.38 mg kg < -1 >. The analysis reason is that under the condition that the microwave energy is enough, the increase of the thickness of the soil layer of the polluted soil in the same container indicates that the soil quality is also increased, so that the contact degree of the polluted soil exposed to the microwave radiation and a microwave field is increased, the soil system converts the absorbed microwave energy into heat energy, the power of the heat energy for maintaining the microwave heating of the polluted soil is also increased, and therefore, the total amount of the microwave energy converted into the heat energy is correspondingly increased. Experimental results show that the microwave thermal remediation efficiency of the petroleum-polluted soil is not reduced along with the increase of the soil thickness. In addition, previous studies show that the microwave heating temperature of soil is related to the electric field intensity of a microwave field, the effective dielectric loss factor of soil and the like, and the direct relationship between the microwave heating temperature of soil and the soil quality is not shown. Therefore, the increase of the treatment amount of the contaminated soil within a certain range does not weaken the temperature raising effect of the soil and the removal efficiency of Nap, but it should be noted that it does not mean that the treatment energy of the contaminated soil can be infinitely increased while the microwave heating temperature of the soil and the removal efficiency of the contaminants are not affected. Because the penetration depth of the microwave into the material is limited. The microwave can directly heat the inside and the outside of the polluted soil in the microwave field simultaneously through the dielectric loss of electromagnetic energy, and can directly enter the inside of the soil without the conduction of a medium, the microwave energy is continuously absorbed by the soil and converted into heat energy, and the field intensity and the power of the microwave field are attenuated at the moment. The penetration depth of the microwaves is used to indicate the ability of the microwaves to penetrate into the soil medium, and exceeding the penetration limit of the microwaves will result in the treated contaminated soil sample not absorbing sufficient microwave energy. In the process of repairing polluted soil by microwaves, although the removal rate of the pollutants by the microwaves can be improved by increasing the thickness of the soil layer, the increase of the thickness of the soil layer needs to have a certain limit, so that the experimental condition for determining the thickness of the soil layer is 3-5 cm within the range of experimental conditions such as microwave intensity and the like.

According to test results, the using conditions suitable for the method are that the microwave power is 540-720W, the microwave irradiation time is 15-25 min, the soil layer thickness is 3-5 cm, and the soil moisture content is 13% -19%.

As shown in fig. 1 to 7, an organic contaminated soil microwave remediation device and a remediation method thereof include an organic contaminated soil microwave remediation device, which is characterized in that: comprises a microwave soil remediation device and a tail gas microwave catalytic combustion device; the microwave soil remediation device comprises a feeding conveyor belt 1, a material conveyor 2 connected to an outlet of the feeding conveyor belt 1, a microwave reaction cavity 4 arranged at the rear end of the material conveyor 2, a gas collecting pipe 5 fixedly connected to a gas outlet of the microwave reaction cavity 4, and a tail gas microwave catalytic combustion device 6 connected to an outlet of the gas collecting pipe 5; the microwave soil remediation device further comprises an output conveyor belt 7 connected to the tail end of the microwave reaction cavity 4 and a homogenizer 8 arranged between the outlet of the material conveyor 2 and the microwave reaction cavity 4; the front end of the microwave reaction cavity 4 is provided with a moisture regulator 3; the material conveyor 2 comprises a driving motor 21, a driving conveying roller 22, a driven conveying roller 23, a material conveying belt 24 and a supporting frame 25; the material conveying belt 24 is sleeved on the driving conveying roller 22 and the driven conveying roller 23; the output shaft of the driving motor 21 is fixedly connected to the driving conveying roller 22; the driving conveying roller 22, the driven conveying roller 23, the moisture regulator 3 and the homogenizer 8 are all fixedly connected to a support frame 25; the microwave reaction cavity 4 is arranged at the upper end of the material conveying belt 24.

The microwave reaction cavity 4 comprises a reaction cavity 41, a gas collecting pipe connecting pipe 42 arranged at the central position of the upper part of the reaction cavity 41, a hopper-shaped recovery cavity 43 sleeved on the tail gas recovery pipe and a first magnetron 44 fixedly connected to the lower end of the gas collecting pipe connecting pipe 42; the material conveying belt 24 is arranged at the lower end of the first magnetron 44; the front end and the rear end of the reaction cavity 41 are both provided with microwave suppressors 45; the lower end of the microwave suppressor 45 is fixedly connected with a temperature measuring probe 46; the gas collecting pipe connecting pipe 42 is communicated with the gas collecting pipe 5; the temperature probe 46 is arranged at the upper end of the material conveying belt 24. The microwave reaction chamber 4 further comprises a furnace door 49 arranged on one side surface of the reaction chamber 41, an observation window arranged on the furnace door 49, a dense metal shielding layer 47 arranged on the observation window and a choke groove 48 arranged around the reaction chamber 41; the choke groove 48 is tightly connected with the oven door 49.

The microwave power of the microwave soil remediation device is continuously adjustable (250-1500W), the rotating speed of the belt conveyor is divided into 3 gears, the width of the belt is 1.5 m, the rotating speed of one gear is 0.33 cm & s < -1 >, the microwave irradiation time is 30.8 min, the rotating speed of the second gear is 0.9 cm & s < -1 >, the microwave irradiation time is 11.2 min, the rotating speed of the third gear is 1.37 cm & s < -1 >, and the microwave irradiation time is 7.4 min. The polluted soil is placed on a conveyer belt from a feeding port at the front end of the device and enters the microwave reaction cavity through a belt conveyor.

The frequency of the first magnetron 44 is 2.45 HZ. The magnetron of the microwave soil remediation device adopts the frequency of 2.45 GHz, and based on the working principle of a microwave resonant cavity, the working mode of the microwave is ensured to be within the central resonant frequency range, and when the selected frequency is 2.45 GHz in the running process of microwave remediation of polluted soil, the electric field can be distributed uniformly. The microwave suppressors 45 are arranged at two ends of the microwave reaction cavity 4, so that the microwave is prevented from leaking from the reaction cavity in the operation process of the microwave soil remediation system, and the generated radiation is released to the environment to harm human health. The temperature measuring probe 46 is used for detecting the change condition of the soil temperature of the equipment in the operation process in real time, and the microwave reaction cavity 4 is also provided with a pressure measuring probe which is used for detecting the change condition of the pressure in the microwave reaction cavity so as to ensure that the soil can reach the temperature required by the removal of target pollutants and the safety performance of the system. Moisture regulator 3 installs at 4 front ends in microwave reaction chamber, is connected with external source water receiving pipe, and the influence of soil moisture content to microwave remediation efficiency is showing, consequently, can realize the regulation to soil moisture content through moisture regulator 3. The observation window of the microwave reaction chamber 4 oven door is provided with a dense metal shielding layer 47 which can effectively resist microwave, the periphery of the oven door 49 is provided with a choke groove 48 structure which can resist microwave leaked from the door seam, the door body is tightly combined with the oven cavity front plate to reflect most of microwave back to the oven cavity, and a small part of leaked microwave is reflected to the choke groove of the door body and can be reflected and consumed in the choke groove. A trace amount of the microwave leaking from the choke groove can be absorbed by the gate seal 481, effectively preventing the microwave radiation from leaking from the gate gap. The oven door of the microwave reaction cavity is provided with the safety interlock, the system can not normally run under the condition of not closing the oven door, the microwave reaction cavity 4 is effectively prevented from starting to work under the condition that the oven door 49 is open, and the safety of human bodies and the surrounding environment is ensured. The homogenizer 8 is installed between the moisture regulator 3 and the microwave reaction chamber 4 (front end), and the homogenizer 8 comprises a fixing frame 81 fixedly connected to the supporting frame 25, a connecting baffle 82 fixedly connected to the fixing frame 81, and a pressure equalizing tooth 83 arranged below the connecting baffle 82.

The repair equipment of the invention is used for verifying the use conditions of the early-stage small experiment:

in the soil remediation process, the electric field distribution rule in the microwave reaction cavity is basically unchanged when the microwave power is different, and the electric field intensity peak value of the microwave field is increased along with the increase of the microwave input power. The change of the microwave power can affect the maximum electric field intensity of the microwave reaction cavity, but hardly affects the electric field distribution rule of the microwave reaction cavity, the microwave field intensity in the microwave reaction cavity is increased while the microwave power is increased, and the microwave field intensity is closely related to the heating and temperature rising process of the microwaves, so that the microwave heating process of the polluted soil can be promoted by increasing the power. The water content of the contaminated soil was 11.25% and the concentration of Nap in the soil was 75.37 mg.kg-1. Under the conditions that the soil feeding thickness is 4 cm and the rotating speed of the conveyor belt is 0.33 cm s < -1 >, different microwave powers, namely 250, 500, 750 and 1000W are set, and the heating temperature and the Nap removal rate of the petroleum-polluted soil are examined along with the change of the microwave irradiation time, as shown in FIG. 8 and FIG. 9.

As can be seen from FIG. 8, the heating rate of the contaminated soil and the maximum heating temperature that can be achieved are generally increased along with the increase of the microwave power and the irradiation time, which is specifically shown in the following that the temperature of the contaminated soil is rapidly increased in the initial stage of microwave irradiation (less than 20 min), and the temperature change of the contaminated soil tends to be stable in 20-30 min. The microwave power is 250W, and the contaminated soil can be heated to 155 ℃ after being irradiated by the microwave for 20 min. The microwave power is increased from 250W to 750W, the temperature rising rate of the polluted soil is obviously improved, the microwave irradiation is carried out for 20 min, and the polluted soil can be heated to 245 ℃. When 1000W of microwave power is applied, the maximum heating temperature of the soil is 256 ℃.

Fig. 9 shows that the removal efficiency of naphthalene contaminants during microwave irradiation of contaminated soil shows a similar trend to the microwave heating temperature rise curve of soil. Under the condition that the microwave output power of the microwave soil remediation device is set to 1000W, 94.1 percent of Nap removal rate can be realized within 20 min of 1000W microwave irradiation, the residual Nap concentration is 4.45 mg.kg < -1 >, and the first type of construction land soil pollution risk screening standard (20 mg.kg < -1 >) is reached. The microwave power is 750W, the microwave heating is carried out for 20 min, the removal rate of Nap in the polluted soil is 92.3 percent, and the concentration of the residual Nap is 5.80 mg.kg < -1 >. The microwave power is 250W and 500W respectively, the removal rate of Nap is 59.5 percent and 71.5 percent respectively by microwave heating for 20 min, and the residual Nap concentration in the soil is 30.52 mg/kg-1 and 21.48 mg/kg-1 respectively. Similar to the temperature variation trend of the contaminated soil, the removal rate of the soil contaminant Nap is correspondingly increased along with the increase of the microwave output power, and the increase amplitude of the removal rate of the Nap is reduced after the microwave power is more than 750W. Experimental results show that the microwave field intensity of the microwave reaction cavity can be improved by increasing the microwave power, the microwave heating effect of the petroleum-polluted soil is enhanced, and the removal efficiency of the petroleum pollutants is effectively improved.

Analysis and verification of soil physicochemical property

In order to investigate the influence of the microwave remediation process on the physicochemical properties of the soil, experimental analysis contrasts the change of the physicochemical properties of the soil before and after microwave remediation, as shown in the following table. The results show that the cation exchange capacity of the soil and the organic matter content of the soil are slightly reduced after the microwave thermal remediation, and the pH value and the soil density of the soil are slightly increased. The contaminated soil is heated by microwave for 20 min, the highest reaction temperature is 290 ℃, the organic matters in the soil are reduced to 3.47 g/kg-1 from the original 4.01 g/kg-1, only 13.47 percent is reduced, and the cation exchange capacity of the soil is reduced by the reduction of the organic matters caused by heating. However, in general, the basic physicochemical properties of the soil before and after microwave remediation are not much different from those of the soil before remediation. This is because the maximum temperature of the soil is maintained at about 290 ℃ during microwave irradiation, and the damage to the physicochemical properties of the soil is smaller in a shorter microwave irradiation time than in other thermal remediation methods.

TABLE 3-1 analysis of soil physicochemical Properties

In order to observe the change of the surface appearance structure of the soil before and after microwave thermal desorption from a microscopic level, the soil before and after microwave thermal remediation is characterized by a Scanning Electron Microscope (SEM) in an experiment. The results show that the soil particles are not uniform in size and are not uniformly distributed before microwave remediation, and part of the soil particles are agglomerated together. Because the petroleum polluted soil contains high-viscosity colloid and asphalt substances and has high concentration, part of soil particles can be bonded and agglomerated. After the microwave thermal desorption treatment is carried out for 20 min, the highest temperature of the soil in the microwave heating process is 280-290 ℃, the viscosity of the soil is slightly reduced along with the removal of pollutants in the soil, the soil particles are more dispersed than before the treatment, and the surfaces of the soil particles are gradually rough. The repairability of the microwave to the petroleum-polluted soil is verified.

Verification of influence of soil moisture on soil temperature rise and Nap removal rate

In general, the water content of soil in an actual petroleum-contaminated site is in the range of several percent to ten and several percent. The tested petroleum polluted soil has the water content of 11.25 percent and the concentration of Nap of 75.37 mg-kg & lt-1 & gt, so that the removal effect of the soil water content on petroleum pollutants in the microwave remediation process is better researched, and the polluted soil with the water content which cannot be measured in series is artificially prepared. Under the conditions that the microwave power is 750W and the feeding thickness of the polluted soil is about 4 cm, the rotating speed of the conveyor belt is adjusted to be 0.33 cm s < -1 >, and the change curves of the microwave heating temperature and the Nap removal rate of the polluted soil along with the irradiation time under different soil moisture contents, namely 5%, 11.25%, 16% and 20%, are examined, and the change curves are shown in a figure 10 and a figure 11.

As can be seen from fig. 10, as the water content of the contaminated soil increases from 5% to 16%, the maximum temperature reached by the soil in the same microwave heating time increases. And (3) heating for 20 min by microwave, wherein the temperature of the polluted soil with the water content of 5 percent is 213 ℃, and the temperature of the polluted soil with the water content of 16 percent is 280 ℃. However, as the water content of the soil increases from 16% to 20%, the temperature rise curve of the soil tends to decrease. The contaminated soil with the water content of 20% is heated for 20 min by microwave, the temperature is 270 ℃, and the temperature is reduced compared with the temperature of the contaminated soil with the water content of 16%. On the other hand, water has a dielectric constant and a dielectric loss factor value, and the relative dielectric constant of water at room temperature is about 77, the dielectric loss factor is about 2, and the dielectric loss factor values of soil and petroleum substances are about 0.02 and about 0.002, respectively, so that it is seen that the dielectric loss factor value of water is much higher than that of soil and petroleum substances, and thus the increase of the soil moisture content enhances the microwave heating of the soil system. In addition, the specific heat capacity of water is usually larger than that of soil, and the specific heat of a soil system is correspondingly increased along with the increase of the water content of the soil, so that the microwave heating capacity of the soil is weakened. The net result of the increased water content of the soil may be a tendency for the ratio of the effective dielectric dissipation factor to the specific heat capacity of the material to increase and then to gradually stabilize as the water content increases. 3-7, the change of the Nap removal rate with time and the change of the soil temperature-rising curve with time show similar trends under different soil water contents. The water content of the polluted soil is increased from 5 percent to 16 percent, the removal rate of Nap is increased from 81.4 percent to 95.6 percent within 20 min, and the residual Nap in the soil is reduced from 14.01 mg.kg < -1 > to 3.32 mg.kg < -1 >. Is far less than the screening value of the soil pollution risk of the first type of construction land. As the water content increased from 16% to 20%, the Nap removal rate began to decrease, and the microwave heating was carried out for 20 min, whereby the Nap removal rate was 93.4%, and the residual Nap in the soil was 4.97 mg kg-1. Therefore, when the soil moisture content is increased to a certain degree, the removal rate of Nap in the soil is reduced along with the increase of the soil moisture content, which is consistent with the experimental result of a laboratory test. The analysis reason is that in the process of microwave heating of the contaminated soil, the evaporation of soil moisture consumes a part of energy, so that the microwave energy consumed by the evaporation of the moisture is increased along with the increase of the soil moisture content, and therefore when the soil moisture content is too high, the wave-absorbing and temperature-raising behaviors of the contaminated soil are weakened, and the removal rate of pollutants in the soil is reduced.

The homogenizer 8 is connected with the baffle 82 and the equalizing tooth 83 in sequence through the fixing frame 81, the thickness of the soil layer of the polluted soil on the conveying belt entering the microwave reaction cavity can be adjusted by the installation of the homogenizer 8, and the soil can be distributed more uniformly. In other embodiments, a height adjusting device may be added to the fixing frame 81 to adjust the thickness of the soil layer for repairing different soil qualities.

Verification of influence of soil layer thickness on soil temperature rise and Nap removal rate

In the test, the influence of the soil layer thickness on the soil temperature rise and the Nap removal rate is set to 750W, the rotating speed of the conveyor belt is 0.33 cm s < -1 >, the rotating speed is 1, 2, 3, 4 and 5 cm under different soil feeding thicknesses, and the microwave heating temperature and the Nap removal rate of the polluted soil change along with the irradiation time, which is shown in a figure 12 and a figure 13. In the microwave thermal remediation process, the temperature of the polluted soil and the removal rate of Nap are not reduced due to the increase of the soil feeding thickness, but are improved along with the increase of the soil layer thickness in a certain range. When the thickness of the soil feed is increased from 1 cm to 4 cm, the microwave irradiation is carried out for 20 min, the microwave heating temperature of the polluted soil is increased from 173 ℃ to 246 ℃, the removal rate of Nap is increased from 82.3 percent to 92.3 percent, and the concentration of the residual Nap in the soil is reduced from 13.34 mg.kg < -1 > to 5.80 mg.kg < -1 >. However, when the soil feed thickness was increased to 5 cm, it was found that the temperature rise curve of the contaminated soil was slightly lowered, and the maximum temperature reached by the soil was 210 ℃ under which the removal rate of Nap was 88.6% and the residual concentration of Nap was 8.59 mg.kg-1. This is because when sufficient microwave energy is provided, an increase in the thickness of the soil feed means an increase in the quality of the contaminated soil within the microwave reaction chamber, resulting in an increase in the total amount of thermal energy converted into the contaminated soil, and the power of the thermal energy to maintain the heating temperature of the contaminated soil increases with the increase in soil quality under the same microwave irradiation conditions. When the microwave thermal remediation process of the polluted soil is carried out, the thickness of the soil layer on the conveyor belt is increased from 1 cm to 4 cm, and the condition that the temperature rising behavior of the soil is weakened does not occur. Although the increase of the treatment capacity of the contaminated soil can enhance the thermal effect of the contaminated soil under microwave irradiation to a certain extent, which is beneficial to the conversion of the thermal energy of the soil, the increase of the treatment capacity of the contaminated soil does not mean that the amount of the contaminated soil can be infinitely increased because the penetration depth of the microwaves is limited, and the penetration of the microwaves are influenced by the feeding thickness of the soil, if the feeding thickness of the soil exceeds the penetration limit of the microwaves, the microwave heating effect of the soil can be weakened, and the removal of pollutants is not facilitated. On the other hand, the amount of the microwave energy consumed by the polluted soil is increased while the treatment capacity of the polluted soil is increased, so that more microwave energy needs to be provided to meet the requirement of soil temperature rise, such as increasing the microwave power and prolonging the microwave irradiation time, but the microwave power is too high, so that the energy is wasted, the control of the microwave irradiation process is influenced, and the instrument is possibly damaged, so that the soil layer thickness needs to be controlled within a reasonable range, and experiments show that the optimal condition is about 4 cm.

The invention can also be provided with a receiving tank at the end of the belt conveyor for receiving cooling water for cooling circulation. The gas collecting pipe 5 is arranged at the rear end of the microwave repairing device and is mainly used for collecting organic gas volatilized from the microwave reaction cavity 4.

The tail gas microwave catalytic combustion device comprises a microwave catalytic combustion reaction cavity 51 communicated with the gas collecting pipe 5, a second magnetron 52 arranged at the upper part of the microwave catalytic combustion reaction cavity 51, a waveguide pipe 53 connected with the second magnetron 52 and a heat exchanger 54 arranged at the lower part of the microwave catalytic combustion reaction cavity 51;

a tail gas circular shell is arranged at the periphery of the microwave catalytic combustion reaction cavity 51 and the heat exchanger 54; the microwave control system 56 is arranged at the upper part of the tail gas round shell; transparent ceramic tubes are arranged on the inner walls of the periphery of the microwave catalytic combustion reaction cavity 51; metal baffles 58 are provided at both ends of the ceramic tube. The exhaust gas microwave catalytic combustion apparatus further comprises a thermocouple 57 vertically inserted into the microwave catalytic combustion reaction chamber 51. The tail gas microwave catalytic combustion device further comprises a circulating water cooling system 55; the circulating water cooling system 55 is connected with the heat exchanger 54 to form a cold and hot water circulation.

The microwave catalytic combustion device is tightly connected with the gas collecting pipe 5, the organic waste gas entering the gas collecting pipe 5 is subjected to microwave catalytic combustion treatment, the microwave catalytic combustion device is effectively prevented from polluting the environment due to harmful gas desorbed from polluted soil, is made of metal materials, and the catalytic combustion reaction chamber is of a cylindrical structure and is made of transparent ceramic pipes. Metal baffles 58 with holes are provided at both ends of the ceramic tube to prevent leakage of microwave radiation, and the microwave reaction chamber is connected to the second magnetron 52 through a waveguide 53 at a certain distance to prevent a reduction in the service life of the second magnetron 52 due to an excessive temperature in the reaction chamber. In addition, in order to reduce the interference of microwave to the temperature measurement of the thermocouple 57, the thermocouple 57 is vertically inserted into the catalytic reaction center in the chamber, and the reaction temperature of the catalytic bed can be monitored in real time.

The application relates to a repairing method of microwave repairing equipment for organic contaminated soil, which comprises the following steps:

firstly, lifting soil to a certain height along a feeding conveying belt 1;

thirdly, performing microwave irradiation on the soil on the lifting path by using microwaves generated by the microwave reaction cavity 4;

thirdly, the speed of the material conveying belt 24 is controlled by controlling the output speed of the driving motor 21 to adjust the feeding speed of the polluted soil;

thirdly, regulating the moisture content of the polluted soil by a moisture regulator 3;

thirdly, the feeding thickness of the soil entering the material conveying belt 24 of the microwave reaction chamber 4 is adjusted through the homogenizer 8;

in addition, a thermocouple 57 was introduced for monitoring in real time the change in temperature of the contaminated soil in the microwave field.

The embodiments described above are only preferred embodiments of the invention and are not exhaustive of the possible implementations of the invention. Any obvious modifications to the above would be obvious to those of ordinary skill in the art, but would not bring the invention so modified beyond the spirit and scope of the present invention.