CN104741372A - Novel thermal desorption restoring system and novel thermal desorption restoring method for treating POPs (persistent organic pollutants) polluted soil - Google Patents

Abstract

The invention proposes a novel thermal desorption restoration method for treating persistent organic pollutants (POPs) polluted soil. The present invention uses cheap charcoal instead of activated carbon as the tail gas adsorbent, and mixes it with polluted soil as a combustion heat source to provide heat for the thermal desorption treatment soil. The thermal desorption process does not require any external The heat is supplied, and the ignited soil spontaneously completes the repair process. In addition, in order to avoid the generation of secondary pollutants, we have built a continuous repair mode, that is, the charcoal after adsorption can be mixed with the polluted soil again, and used as the combustion heat source for the next thermal desorption reaction. The cycle is repeated, and finally the The purpose of remediating POPs-contaminated soil is efficient, economical and environmentally friendly. Each sample after heat treatment was extracted by accelerated solvent extraction method, acidified with sulfuric acid, purified by multi-layer chromatography column, and finally the effect of repair treatment was verified by GC-MS and other analysis and test methods.

Description

A novel thermal desorption remediation system and method for treating POPs-contaminated soil

technical field

The invention belongs to the field of soil restoration, and in particular relates to a novel thermal desorption restoration system and method for treating polluted soil.

Background technique

The new thermal desorption technology for treating POPs-contaminated soil is developed based on the optimization and improvement of the traditional thermal desorption technology and combined with the sintering process. Although the traditional thermal desorption technology has the advantages of high remediation efficiency, stable reaction process and relatively simple operation, it still has the disadvantages of high energy consumption and high treatment cost in the process of treating actual POPs-contaminated soil, and will generate Secondary pollutants, such as: chlorobenzene, dioxin, etc., if the tail gas is not properly treated or the adsorbent is saturated, it is very easy to discharge excessive pollutants into the atmosphere, causing damage to the surrounding environment and human health. Serious harm. In addition, the carbonized substances (such as: activated carbon) adsorbed in the tail gas after use, etc., need to be treated again because they contain a large amount of pollutants, which will further increase the cost of treatment. Based on this, in order to reduce treatment energy consumption, cost and avoid secondary pollutants, this technology research and development of a new thermal desorption technology that uses charcoal as an exhaust gas adsorbent and combustion heat source at the same time. In the continuous repair mode, charcoal with strong adsorption capacity and low price is firstly selected to replace activated carbon as the tail gas adsorbent to adsorb the POPs in the tail gas generated during the thermal desorption process; secondly, the used charcoal is combined with POPs The polluted soil is mixed again in a certain proportion, so that it can act as a combustion heat source in the subsequent reaction process. This not only avoids the trouble of reprocessing the charcoal, but also uses the heat emitted by the charcoal for heating, which saves the processing cost.

POPs substances are a kind of bioaccumulative, refractory, highly toxic organic pollutants that exist in the environment and can migrate long distances with the atmosphere. Serious hazard to health. Once POPs substances are produced, they will first enter the atmosphere with industrial discharge activities, etc., and can migrate to places far away from the pollution source; after that, they can return to the ground and rivers through processes such as atmospheric deposition, and finally accumulate in soil or water deposits in things. It can enter the food chain through the re-release process of pollutants, accumulate in various animals and plants through bioaccumulation, and finally enter the human body. Therefore, in order to reduce the harm of POPs, the prevention and restoration of its contaminated soil has attracted extensive attention of domestic and foreign researchers.

Although in recent years, a variety of technologies for remediation of POPs-contaminated soil have been continuously researched and developed, but there are not many applied technologies with real practical value, and considering factors such as treatment cost, treatment time, and energy consumption, they can be used for actual POPs-contaminated site remediation , and can achieve better repair effect of the technology is very few. Therefore, there is an urgent need for a low-cost and effective POPs-contaminated soil remediation method.

Contents of the invention

The purpose of the present invention is to provide a novel thermal desorption repair system and method for treating POPs-contaminated soil under lower treatment cost and energy consumption conditions, so as to realize the restoration, purification and reuse of POPs-contaminated soil .

In order to solve the problems of the technologies described above, the present invention provides the following technical solutions:

A novel thermal desorption repair system for treating POPs polluted soil, the novel thermal desorption repair system includes a thermal desorption treatment system and a tail gas treatment system; the thermal desorption treatment system includes a constant temperature device and a reaction device, the reaction The device is placed in a constant temperature device; the tail gas treatment system includes a soil adsorption column, a water collection part, a cooling part, a charcoal adsorption column and XAD resin, and the devices in the above tail gas treatment system are connected through communication parts; the thermal desorption The treatment system and the tail gas treatment system are connected through communication components.

Further, the novel thermal desorption repair system also includes a flow meter and a vacuum pump, and the flow meter and the vacuum pump are connected to the XAD resin through connecting parts.

Further, the flow meter is a DC-5 dry flow meter, and the vacuum pump is a diaphragm vacuum pump.

Further, the soil in the soil adsorption column is POPs polluted soil.

Further, the connecting part is a polytetrafluoroethylene hose or a glass tube.

Another object of the present invention is achieved through the following technical solutions:

A novel thermal desorption remediation method for treating POPs-contaminated soil, the thermal desorption remediation method is realized by the above-mentioned novel thermal desorption remediation system for treating POPs-contaminated soil, and the method includes the following steps:

(1) Soil pretreatment: Mix contaminated soil with charcoal to prepare soil charcoal mixture, and spread the mixture in the reaction device;

The mass ratio of the charcoal to the soil charcoal mixture is 10%-30%.

(2) Thermal desorption treatment: place the reaction device described in step (1) in the constant temperature device, turn on the temperature switch of the constant temperature device, and place the preheated carbon block in the reaction device to realize the desorption of the soil charcoal mixture. Spontaneous combustion while turning on the vacuum pump;

(3) Tail gas treatment: After the vacuum pump is turned on, the tail gas generated during the thermal desorption process is led out from the bottom of the reaction device, enters the tail gas treatment system, and passes through the soil adsorption column, water collection part, cooling part, charcoal adsorption column and XAD resin in sequence , to realize tail gas treatment, the charcoal adsorption column obtains secondary charcoal after the tail gas passes through;

(4) When the temperature of the soil charcoal mixture drops below 500°C, turn off the vacuum pump; when the temperature of the soil charcoal mixture drops to 40°C, turn off the temperature switch of the thermostat to obtain the treated soil;

(5) The secondary charcoal described in step (3) can be recycled, and the secondary charcoal is mixed with the polluted soil to obtain a soil charcoal mixture, and the polluted soil can be recovered by following the above steps (1)-(4) sequentially. repair.

Further, in step (1), a layer of sand is evenly spread on the surface of the reaction device, and then the soil charcoal mixture is spread on the sand.

Further, the reaction device described in step (1) is fixed in a constant temperature device, and the induction tubes of thermocouples are inserted at equal intervals according to the height of the soil charcoal mixture in the reaction device to measure the temperature changes of different sample layers.

Further, the charcoal described in the step (1) is dried, and the condition of the drying treatment is 85° C.-95° C. for 3-5 hours.

Further, the particle size of the charcoal is less than 2mm.

Further, the preheating of the carbon block in step (2) is realized in a muffle furnace, and the temperature of the muffle furnace is set at 600°C.

Further, the pollutants of the POPs polluted soil include OCPs, PCBs or PCDD/Fs and mixtures of several kinds. There are four kinds of polluted soils, namely Beijing fluvo-aquic soil, Heilongjiang black soil, Hunan red soil and Beijing sandy soil.

Compared with the prior art, the novel thermal desorption technology for repairing POPs-contaminated soil of the present invention has the following beneficial effects:

1. This method uses charcoal instead of activated carbon. Compared with activated carbon, the price of charcoal will be much lower, only one-tenth of activated carbon. Studies have shown that the adsorption capacity of charcoal can meet the requirements of organic tail gas adsorption. Compared with Under these conditions, using charcoal as the tail gas adsorbent has higher economic benefits;

2. The present invention mixes charcoal and polluted soil as a combustion heat source, and the reaction process can be carried out spontaneously only by igniting the ignition source, without continuous external heat supply, which will save a lot of energy and reduce energy consumption;

3. In the novel thermal desorption repair method for POPs polluted soil of the present invention, the charcoal of the tail gas adsorbent is used again, and mixed with the polluted soil as a combustion heat source, which improves the utilization efficiency of raw materials, saves costs, and avoids the pollution of tail gas. The complex process of secondary treatment by adsorbent simplifies the remediation treatment process.

Description of drawings

Fig. 1 is the schematic diagram of novel thermal desorption treatment system of the present invention;

Figure 2 Diagram of the continuous repair model.

Detailed ways

In order to further introduce the present invention, the detailed steps and examples of its experimental process are introduced below. According to the Stockholm Convention, POPs substances can be divided into three categories, namely: pesticides (lindane, hexachlorobenzene, etc.), industrial products (polychlorinated biphenyls) and dioxins (dioxins). One of the three categories is now selected as the research object substance of the embodiment.

Example 1

A novel thermal desorption repair system for treating POPs polluted soil, the novel thermal desorption repair system includes a thermal desorption treatment system and a tail gas treatment system; the thermal desorption treatment system includes a constant temperature device and a reaction device, the reaction The device is placed in a constant temperature device; the tail gas treatment system includes a soil adsorption column, a water collection part, a cooling part, a charcoal adsorption column and XAD resin, and the devices in the above tail gas treatment system are connected through communication parts; the thermal desorption The treatment system and the tail gas treatment system are connected through communication components. Further, the connecting part is a polytetrafluoroethylene hose or a glass tube.

XAD resin is an aromatic hydrocarbon polymer (also known as: macroporous adsorption resin or fully porous resin), widely used in hydrophobic compounds; separation of phenol and organic matter; surfactants; aromatic hydrocarbon compounds; catalysts; metals; antibiotic extraction, etc. .

Further, the novel thermal desorption repair system also includes a flow meter and a vacuum pump, and the flow meter and the vacuum pump are connected to the XAD resin through connecting parts.

Further, the flow meter is a DC-5 dry flow meter, and the vacuum pump is a diaphragm vacuum pump.

Further, the soil in the soil adsorption column is POPs polluted soil.

A novel thermal desorption remediation method for treating POPs-contaminated soil, the thermal desorption remediation method is realized by the above-mentioned novel thermal desorption remediation system for treating POPs-contaminated soil, and the method includes the following steps:

(1) Soil pretreatment: Mix polluted soil with charcoal to prepare a soil charcoal mixture, spread the mixture in the reaction device; the mass ratio of the charcoal to the soil charcoal mixture is 10%-30% ;

(2) Thermal desorption treatment: place the reaction device described in step (1) in the constant temperature device, turn on the temperature switch of the constant temperature device, and place the preheated carbon block in the reaction device to realize the desorption of the soil charcoal mixture. Spontaneous combustion while turning on the vacuum pump;

(3) Tail gas treatment: After the vacuum pump is turned on, the tail gas generated during the thermal desorption process is led out from the bottom of the reaction device, enters the tail gas treatment system, and passes through the soil adsorption column, water collection part, cooling part, charcoal adsorption column and XAD resin in sequence , to realize tail gas treatment, the charcoal adsorption column obtains secondary charcoal after the tail gas passes through;

(4) When the temperature of the soil charcoal mixture drops below 500°C, turn off the vacuum pump; when the temperature of the soil charcoal mixture drops to 40°C, turn off the temperature switch of the thermostat to obtain the treated soil;

(5) The secondary charcoal described in step (3) can be recycled, and the secondary charcoal is mixed with the polluted soil to obtain a soil charcoal mixture, and the polluted soil can be recovered by following the above steps (1)-(4) sequentially. repair.

Further, in step (1), a layer of sand is evenly spread on the surface of the reaction device, and then the soil charcoal mixture is spread on the sand.

Further, the reaction device described in step (1) is fixed in a constant temperature device, and the induction tubes of thermocouples are inserted at equal intervals according to the height of the soil charcoal mixture in the reaction device to measure the temperature changes of different sample layers.

Further, the charcoal described in the step (1) is dried, and the condition of the drying treatment is 85° C.-95° C. for 3-5 hours.

Further, the particle size of the charcoal is less than 2mm.

Further, the preheating of the carbon block in step (2) is realized in a muffle furnace, and the temperature of the muffle furnace is set at 600°C.

Example 2

This embodiment is a preferred scheme based on Example 1, and the novel thermal desorption restoration for the treatment of POPs-contaminated soil includes the following steps:

1. New thermal desorption treatment process

(1) Weigh 50g of sand, 25g of charcoal and 75g of soil (charcoal accounts for 25%) and mix the charcoal and soil evenly to obtain a soil charcoal mixture;

(2) Transfer the sand to the reaction tube, spread it flat, and use a ruler to measure the distance from the upper end of the reaction tube to the sand and record it;

(3) Pour the mixed soil charcoal mixture into the reaction tube, spread it flat, and measure the distance to the upper end, and record;

(4) After filling the soil charcoal mixture, fix the reaction tube in the incubator, insert the induction tubes of thermocouples at equal intervals according to the height of the sample in the reaction tube, and measure the temperature changes of different sample layers;

(5) Turn on the thermostat temperature switch and thermocouple switch;

(6) Transfer the carbon block burned in the muffle furnace (the whole carbon block is red) to the reaction tube with crucible tongs, and turn on the vacuum pump at the same time, and the heat treatment experiment begins;

(7) When the temperature of each soil layer drops below 500°C, turn off the vacuum pump; when the temperature drops to about 40°C, turn off the power of the incubator, store the data of the thermocouple and turn off the thermocouple to obtain the soil after thermal desorption treatment.

2. Sample pretreatment

The soil after the thermal desorption treatment was sampled respectively, a certain amount of diatomaceous earth was added, and then accelerated solvent extraction, acidification, multi-layer chromatography column purification, rotary evaporation and nitrogen blowing were carried out in sequence. The specific experimental conditions were as follows:

(1) Accelerated solvent extraction

The extractant is n-hexane and dichloromethane (volume ratio: 1:1); extraction conditions: 100°C, heating at 10.34MPa for 5 minutes, static extraction for 5 minutes, flushing volume of 100%, nitrogen purge time of 60s, cycle 3 times , take the extract for testing.

(2) Acidification with sulfuric acid

The solution after accelerated solvent extraction was transferred to a separatory funnel, an appropriate amount of concentrated sulfuric acid was added, oscillated, left to stand, and the liquid in the lower layer was released, and so operated N times until the upper layer solution was colorless and transparent.

(3) Multi-layer chromatography column purification

The preparation method of the multi-layer chromatography column: from bottom to top are 1g silica gel, 4g basic silica gel, 1g silica gel, 8g acid silica gel, 2g silica gel, 4g anhydrous sodium sulfate.

(4) Rotary evaporation

The acidified solution was transferred to a flask, and evaporated on a rotary evaporator until 5ml of the solution remained in the flask, and the evaporation was stopped.

(5) Nitrogen blowing

Move the solution after rotary evaporation to a KD bottle, and blow with nitrogen on a nitrogen blower until the solution is reduced to 1ml, and then stop the operation.

3. GC-MS analysis and determination

The experimental analysis adopts Agilent 7890A, the capillary column used is DB-5MS, 15m×0.25mm×0.1μm low-bleed elastic quartz capillary column, the carrier gas is high-purity nitrogen, and the chromatographic data is collected by micro-electron capture detector (μECD). The qualitative analysis of each pollutant was carried out by MS.

Chromatographic conditions: the inlet temperature is 290°C, the initial temperature is 80°C, keep for 0.75min; rise to 240°C, keep for 3min, and the heating rate is 10°C/min; then rise to 290°C, keep for 12min, and the heating rate is 20°C /min.

Transfer the solution in the KD-concentrated bottle to the sample bottle for analysis and determination on the machine.

Example 3

This example is a preferred solution based on Examples 1 and 2. This example is a new type of thermal desorption treatment for organochlorine pesticides (OCPs) polluted soil. Before the treatment, the concentration of organochlorine pesticides (OCPs) polluted soil is : 16 mg kg ^-1 , the components mainly include: hexachlorobenzene (HCB), DDT (DDT) and hexahexample (HCHs).

The thermal desorption repair method refers to Example 2.

(1) Processing efficiency

After thermal desorption treatment, the residual amount of OCPs in the soil is only: 0.25-0.46 mg kg ^-1 , and the degradation rate can reach more than 97%.

(2) Content of pollutants in exhaust gas

After thermal desorption treatment, the concentration of OCPs in the tail gas was within the range of 0.02-0.06 mg Nm ^-3 , and no more toxic organic pollutants such as dioxin were detected.

Example 4

This example is a preferred solution based on Examples 1 and 2. This example is a new type of thermal desorption treatment for polychlorinated biphenyls (PCBs) polluted soil, and the thermal desorption restoration method refers to Example 2.

(1) Processing efficiency

Before and after thermal desorption treatment, the removal rate and degradation rate of PCBs can be calculated by the following two formulas:

Removal rate RE _PCBs (%) = (initial concentration of PCBs in soil - concentration in soil after PCBs treatment) ÷ initial concentration of PCBs in soil

Degradation rate DEPCBs (%) = (initial concentration of PCBs in soil-concentration in soil after PCBs treatment-concentration of PCBs charcoal adsorption column-concentration of PCBs cooling part-concentration in PCBs tail gas) ÷ initial concentration of PCBs in soil

It can be obtained by calculation that in the process of using the new thermal desorption treatment technology to remediate different PCBs-contaminated soils, the removal rate of PCBs can reach more than 99%, and the initial concentration of PCBs-contaminated soil will not affect its removal rate; while PCBs degradation The degradation rate is above 70%, and its degradation rate will increase with the increase of PCBs pollution concentration. When the initial concentration is 90mg kg-1PCBs polluted soil, its degradation rate can reach more than 85%.

(2) Structural composition of PCBs in soil after treatment

Before thermal desorption treatment, the structural composition of PCBs-contaminated soil was as follows: 4-chlorinated PCBs accounted for the most components, reaching more than 60%, followed by 3-chlorinated PCBs, 5-chlorinated PCBs and 6-chlorinated PCBs, and high-chlorinated PCBs The proportion of generation PCBs (6-10) is very small, only 2.2%. However, the structural composition of PCBs changed significantly after thermal desorption treatment. The main manifestations were: the components of low-chlorinated PCBs increased, while the components of high-chlorinated PCBs were not detected. According to calculation, 1-4 chlorinated PCBs accounted for more than 95% of the total PCBs residues. This indicates that during the thermal desorption process, PCBs mainly undergo dechlorination and degradation reactions.

(3) The content of pollutants in the exhaust gas

After thermal desorption treatment, the total amount of PCBs in PCBs-contaminated soil tail gas was 0.012-0.019 mg Nm ^-3 , far below the international standard limit value for PCBs exhaust, and only low-chlorinated PCBs (less than 6 chlorinated PCBs ) were detected in the exhaust. In addition, since PCBs are the precursors of dioxin substances, they can be transformed under certain conditions to produce more toxic PCDD/Fs substances. Therefore, the PCDD/Fs content in the exhaust gas was also detected in the study. The results show that its concentration value is 0.19-0.25 ng Nm ^-3 , converted into toxic equivalent concentration: 0.00047-0.00081ng-TEQ Nm ^-3 , meeting the international emission requirements for dioxin substances (0.1 ng-TEQ Nm ^{- 3} ). This is mainly because the treatment temperature of the new thermal desorption technology is higher (higher than 600 degrees Celsius), and the tail gas temperature cooling unit is set at the tail gas treatment end, which can better inhibit the regeneration of dioxin substances.

Example 5

This example is a preferred solution based on Examples 1 and 2. This example is a new type of thermal desorption treatment for dioxin-contaminated soil. Refer to Example 2 for the thermal desorption restoration method.

(1) Processing efficiency

As shown in Table 1, before thermal desorption treatment, the total concentration and toxic equivalent concentration of dioxin substances PCDD/Fs were: 500,000 ng g ^-1 and 1340 ng-TEQ g ^-1 , far exceeding the environmental 1000 pg-TEQ g ^-1 of dioxin-contaminated soil. However, after the treatment, the concentration of PCDD/Fs in the soil decreased to 66-1770 pg g ^-1 , and the corresponding toxic equivalent concentration also decreased to 0.0078-23 pg-TEQ g ^-1 , much lower than the dioxin soil in the environment Toxic equivalent concentration limit. It can be obtained by calculation that the removal efficiency of PCDD/Fs can reach more than 99%. Some experimental conditions, such as: changes in air flow rate will affect the removal efficiency of dioxins, but all meet the concentration requirements after treatment.

Table 1 PCDD/Fs concentration and removal efficiency in soil before and after treatment

(2) Structural composition of dioxins in soil after treatment

Before thermal desorption treatment, the content of PCDDs was higher than that of PCDFs, the ratio was 1.9. It can be seen from Table 1 that highly chlorinated PCDD/Fs, such as: 8-chlorinated OCDD, OCDF, 7-chlorinated HpCDD, and HpCDF account for a large proportion of the structure of dioxins. Then, after thermal desorption treatment, the structural composition of 4-8 chlorinated PCDD/Fs did not change significantly, and still showed a trend of gradually decreasing concentration from high chlorinated to low chlorinated PCDD/Fs. This shows that: in the whole remediation process, the degradation reaction of dioxin substances is the main one, and the dechlorination reaction does not play a very important role. In addition, the degradation efficiency of PCDDs is higher than that of PCDFs, which may be related to the fact that the initial concentration of PCDDs is much higher than that of PCDFs in dioxin-contaminated soil.

(3) The content of pollutants in the exhaust gas

After thermal desorption treatment, the concentration range of PCDD/Fs in the tail gas is between 0.087-0.67 pg-TEQ Nm-3, which all meet the international general emission standard of dioxin substances (100 pg-TEQ Nm-3).

It should be declared that the above summary of the invention and specific implementation methods are intended to prove the practical application of the technical solutions provided by the present invention, and should not be interpreted as limiting the protection scope of the present invention. Those skilled in the art may make various modifications, equivalent replacements or improvements within the spirit and principle of the present invention. The protection scope of the present invention shall be determined by the appended claims.

Claims (10)

1. A novel thermal desorption repair system for processing POPs polluted soil, characterized in that, the novel thermal desorption repair system comprises a thermal desorption treatment system and a tail gas treatment system; the thermal desorption treatment system comprises a constant temperature device and A reaction device, the reaction device is placed in a constant temperature device; the tail gas treatment system includes a soil adsorption column, a water collection part, a cooling part, a charcoal adsorption column and XAD resin, and the devices in the above tail gas treatment system are connected through communication parts ; The thermal desorption treatment system and the tail gas treatment system are connected through a communication component. 2. The novel thermal desorption repair system for processing POPs polluted soil according to claim 1, characterized in that, the novel thermal desorption repair system also includes a flow meter and a vacuum pump, and the flow meter and the vacuum pump are connected to each other through connecting parts XAD resin is connected. 3. The novel thermal desorption repair system for treating POPs-contaminated soil according to claim 2, wherein the flow meter is a DC-5 dry flow meter, and the vacuum pump is a diaphragm vacuum pump. 4. The novel thermal desorption repair system for treating POPs-contaminated soil according to claim 1, wherein the soil in the soil adsorption column is POPs-contaminated soil. 5. A novel thermal desorption restoration method for processing POPs-contaminated soil, characterized in that, the thermal desorption restoration method is realized by the novel thermal desorption restoration system for processing POPs-contaminated soil according to claims 1-4, the Said method comprises the following steps: (1) Soil pretreatment: Mix contaminated soil with charcoal to prepare soil charcoal mixture, and spread the mixture in the reaction device; (2) Thermal desorption treatment: place the reaction device described in step (1) in the constant temperature device, turn on the temperature switch of the constant temperature device, and place the preheated carbon block in the reaction device to realize the desorption of the soil charcoal mixture. Spontaneous combustion while turning on the vacuum pump; (3) Tail gas treatment: After the vacuum pump is turned on, the tail gas generated during the thermal desorption process is led out from the bottom of the reaction device, enters the tail gas treatment system, and passes through the soil adsorption column, water collection part, cooling part, charcoal adsorption column and XAD resin in sequence , to realize tail gas treatment, the charcoal adsorption column obtains secondary charcoal after the tail gas passes through; (4) When the temperature of the soil charcoal mixture drops below 500°C, turn off the vacuum pump; when the temperature of the soil charcoal mixture drops to 40°C, turn off the temperature switch of the thermostat to obtain the treated soil; (5) The secondary charcoal described in step (3) can be recycled, and the secondary charcoal is mixed with the polluted soil to obtain a soil charcoal mixture, and the polluted soil can be recovered by following the above steps (1)-(4) sequentially. repair. 6. The novel thermal desorption restoration method for treating POPs-contaminated soil according to claim 5, characterized in that, in step (1), first evenly spread a layer of sand on the surface of the reaction device, and then flatten the soil charcoal mixture Spread over the grit. 7. The novel thermal desorption restoration method for treating POPs-contaminated soil according to claim 6, characterized in that the reaction device in step (1) is fixed in a constant temperature device, and according to the height of the soil charcoal mixture in the reaction device, press The sensing tubes of the thermocouples are inserted at equal intervals to measure the temperature change of the different sample layers. 8. The novel thermal desorption repair method for treating POPs-contaminated soil according to any one of claims 5-7, characterized in that the charcoal described in step (1) is dried, and the dried The condition is 85°C-95°C, 3-5h. 9. The novel thermal desorption restoration method for treating POPs-contaminated soil according to claim 5, characterized in that the particle size of the charcoal is less than 2mm. 10. The novel thermal desorption remediation method for treating POPs-contaminated soil according to claim 5, wherein the pollutants in the POPs-contaminated soil include OCPs, PCBs or PCDD/Fs.