Organic Polluted Soil Remediation System and Technology Based on Ex-situ SVE

Abstract

This invention discloses an organic polluted soil remediation system and process based on ex-situ SVE (Self-Volatilization and Ventilation). The system includes a centrifugal compression component, a heating component, a rotary airlift component, a cyclone separator component, a fixed bed component, and a ventilation component arranged in a closed loop and connected in sequence. This system facilitates the circulation and full utilization of heat and oxygen, and allows for the thorough catalytic purification of organic waste gas. The centrifugal compression component and the heating component pressurize and heat the air drawn in from the outside and guide it to the bottom of the rotary airlift component. The rotary airlift component carries away organic pollutants from the polluted soil using high-temperature and high-pressure air, thereby purifying the soil. The cyclone separator removes dust from the air discharged from the rotary airlift component. The fixed bed component purifies organic pollutants and fixes carbon. After multiple cycles, when the concentration of VOCs and SVOCs in the purified gas is less than 50 mg / kg, the purified gas that meets the emission standards can be discharged.

Description

Technical Field

[0001] This invention relates to the field of soil remediation, specifically to the remediation of soil contaminated with volatile organic compounds (VOCs) and some semi-volatile organic compounds (SVOCs), and particularly to a system and process for remediating organic contaminated soil based on ex-situ SVE.

[0002] Background technology.

[0003] Volatile organic compounds such as VOCs and SVOCs are major pollutants in the atmosphere. These pollutants not only cause frequent smog, damage the ozone layer, and participate in atmospheric reactions to cause acid rain, but also pose a great health threat as they volatilize and enter the human body due to their extremely high irritant, carcinogenic, and teratogenic effects.

[0004] For organic pollutants such as VOCs and SVOCs in contaminated soil, there are currently four common soil remediation technologies: soil washing, ex-situ thermal desorption, soil air stripping, and microbial remediation.

[0005] Soil leaching refers to the deep washing of contaminated soil using specific leaching agents. It is suitable for treating unsaturated areas of soil pollution with good permeability and uniformity. By separating and purifying the leaching agent, it can be reused and integrated to remove pollutants from the soil and ultimately safely dispose of the pollutants and remediate the soil.

[0006] Ex-situ thermal desorption refers to the process of heating organic pollutants in soil after its location has been changed to a sufficient temperature through direct or indirect heat exchange under vacuum conditions or when a carrier gas is introduced, so that the volatile organic pollutants can be volatilized or separated from the polluted medium and enter the gas treatment system; that is, the ex-situ SVE technology described in this application.

[0007] Soil in-situ airlift refers to the process of using a specialized underground extraction (well) system to force the flow of gas in unsaturated soil by drawing a vacuum or injecting air, thereby removing volatile and semi-volatile organic pollutants and achieving the goal of cleaning the soil.

[0008] Microbial remediation refers to a remediation technology that utilizes indigenous or artificially domesticated microorganisms with specific functions to reduce the activity of harmful pollutants in the soil or degrade them into harmless substances through their own metabolism under suitable environmental conditions. It is low-cost and has a relatively small impact on human health, soil, and the environment.

[0009] However, the aforementioned existing methods for treating soil contaminated with organic matter inevitably suffer from serious drawbacks such as high equipment costs, limited range of soil types that can be treated, or harm to the atmospheric environment during the soil purification process. Summary of the Invention

[0010] To overcome the above shortcomings, the present invention provides a system and process for remediating organic polluted soil based on ex-situ SVE.

[0011] This invention can effectively treat soil contaminated with various organic pollutants. Furthermore, because the consumable is air, and the gas is recyclable, energy consumption and costs are significantly reduced. This invention overcomes the common shortcomings of four common remediation methods, reduces energy consumption and costs, improves remediation effectiveness, and achieves complementary advantages over the original methods.

[0012] The technical solution adopted by this invention to solve its technical problem is as follows:

[0013] Organic contaminated soil remediation system based on ex-situ SVE, including

[0014] The centrifugal compression assembly, heating assembly, rotary air lifting assembly, cyclone separation assembly, fixed bed assembly, and air exchange assembly are connected in sequence.

[0015] The centrifugal compression assembly and heating assembly are used to pressurize and heat the air drawn in from the outside and direct it to the bottom of the rotary airlift assembly;

[0016] The rotary airlift assembly is used to carry out organic pollutants in the contaminated soil with high temperature and high pressure air to purify the soil. It includes a rotary chamber and soil inlet, soil outlet, air inlet and air outlet set at various locations. The rotary chamber is equipped with a spiral component for stirring and transporting the soil.

[0017] The cyclone separator is used for dust removal from the exhaust gas of the rotary airlift assembly;

[0018] The fixed bed assembly is used to purify organic pollutants and fix carbon. It includes a flow area, a catalytic purification area and a carbon fixation area arranged from the outside to the inside. The areas are connected and nested in sequence. The flow area is supplied with air from the top and connected to the catalytic purification area from the bottom. The catalytic purification area is provided with multiple layers of filter cake, and the filter cake is embedded with an oxidation catalyst. The purified mixed gas is introduced into the carbon fixation area through the top of the catalytic purification area. The carbon fixation area is provided with multiple layers of filter cake, and the filter cake is embedded with a carbon fixation catalyst.

[0019] The ventilation assembly includes a ball valve I, a ball valve II, and a check valve. The ball valve II is connected to the exhaust port of the fixed bed assembly and the intake port of the centrifugal compression assembly. The ball valve I is located on the branch between the ball valve II and the exhaust port, and the check valve is located on the branch between the ball valve II and the intake port.

[0020] As an improvement to the above technical solution, when ventilation is required, soil intake is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / kg, the ball valve II is closed and the ball valve I is opened, allowing the purified gas to be discharged through the ball valve I. At the same time, the pressure difference generated by the decrease in air pressure inside the system causes the check valve to open automatically, and the centrifugal compression component draws in fresh air from the outside.

[0021] When the oxygen content in the system rises back to above 20%, the ball valve I is closed and the ball valve II is opened. The increased gas pressure inside the system creates a pressure difference, causing the check valve to close automatically, and then the gas re-enters the circulation.

[0022] As an improvement to the above technical solution, the check valve includes an opening and closing baffle that is automatically opened and closed under air pressure control and a fixed baffle that cooperates with it. When the pipeline where the check valve is located is under negative pressure, the opening and closing baffle rotates to open. When the pipeline where the check valve is located is under positive pressure, the opening and closing baffle rotates to be tightly attached to the fixed baffle to seal and close.

[0023] As an improvement to the above technical solution, the soil inlet and outlet are located diagonally opposite to the rotary cavity, and the soil inlet is located at a high position.

[0024] The air inlet is located at the bottom of the soil inlet side of the rotary cavity, and the air outlet is located at the top of the rotary cavity;

[0025] The air inlet is connected to an exhaust pipe located at the bottom of the rotating chamber. The exhaust pipe has an exhaust hole to eject high-temperature and high-pressure gas.

[0026] The inlet is connected to an inlet pipe, which is inclined inward. A sealing baffle is installed inside the pipe. When the sealing baffle is hanging down in its natural state, its lower end abuts against the bottom of the pipe to seal the pipe.

[0027] A spring baffle is installed at the soil outlet.

[0028] As an improvement to the above technical solution, the oxidation catalyst is an encapsulated bimetallic Rh-Mn cluster catalyst, which, when raised to a specific temperature, catalyzes the reaction of organic pollutants such as VOCs and SVOCs with oxygen to generate carbon dioxide and water, thereby purifying organic pollutants.

[0029] The carbon fixation catalyst is a zirconium oxide or alumina-based molecular sieve catalyst. Its microporous structure has the ability to selectively adsorb carbon dioxide molecules to maintain the carbon dioxide content at a level comparable to or lower than that in the air, thus preventing the gas from being released from the device during the ventilation process and exacerbating the greenhouse effect.

[0030] As an improvement to the above technical solution, the bottom of the fixed bed assembly is equipped with a detector that can monitor the internal temperature, pressure, oxygen concentration and concentration of organic pollutants such as VOCs in real time.

[0031] The detector transmits data to a mobile device via a Bluetooth communication module, allowing the operator to control the rotation speed of the screw and the temperature, air pressure, and ventilation process within the system based on real-time data feedback.

[0032] To achieve its inventive objective, the present invention also provides the following technical solutions:

[0033] Organic soil remediation technology based on ex-situ SVE, including

[0034] Keep ball valve I closed and ball valve II open;

[0035] Start the centrifugal compressor assembly, and use the pressure it generates to open the check valve and draw in air from the outside. When the pressure inside the system reaches a certain value, the check valve automatically closes, and the internal gas enters the circulation.

[0036] The inhaled gas is heated and pressurized by passing through the centrifugal compression component and the heating component. The resulting high-temperature and high-pressure air enters the rotary airlift component and is ejected at high speed from the bottom. It passes through the cracks in the contaminated soil, comes into full contact with it, and carries away the volatile organic pollutants and some dust in the soil.

[0037] The mixed gas is then sent to the cyclone separator for dust removal. After dust removal, the mixed gas enters the fixed bed assembly and passes through its outer, middle and inner layers to remove organic pollutants and fix carbon dioxide, respectively.

[0038] The internal gas re-enters the circulation;

[0039] After repeated cycles, when the concentration of VOCs and SVOCs in the purified gas is less than 50 mg / kg, keep ball valve I in the open state and ball valve II in the closed state to discharge the purified gas.

[0040] As an improvement to the above technical solution, after multiple cycles, when the oxygen concentration in the system drops below the set 200ppm, the system will automatically exchange air through the ventilation component to replenish the required oxygen in a timely manner.

[0041] As an improvement to the above technical solution, when ventilation is required, soil intake is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / kg, the ball valve II is closed and the ball valve I is opened, allowing the purified gas to be discharged through the ball valve I. At the same time, the pressure difference generated by the decrease in air pressure inside the system causes the check valve to open automatically, and the centrifugal compression component draws in fresh air from the outside.

[0042] When the oxygen content in the system rises back to above 20%, the ball valve I is closed and the ball valve II is opened. The increased gas pressure inside the system creates a pressure difference, causing the check valve to close automatically, and then the gas re-enters the circulation.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention innovatively proposes a system and process for treating organic polluted soil based on ex-situ airlift SVE, realizing the organic combination and complementary advantages of soil airlift and thermal desorption, making the process of treating polluted soil simpler, more convenient, less polluting to the environment, energy-saving, efficient and low-cost.

[0045] Firstly, this invention overcomes the shortcomings of in-situ soil treatment methods, such as the need to purchase ozone at high cost and the pollution caused by the release of organic waste gas from the soil into the atmosphere, through ex-situ soil treatment. The process flow is designed as a closed loop, which is conducive to the circulation and full utilization of heat and oxygen, and allows the organic waste gas to be fully catalytically purified. After the gas passes through the fixed bed, it carries some residual heat into the next cycle, making full use of the heat generated by the heater to achieve energy saving.

[0046] Secondly, this invention uses an air stripping process to remove organic pollutants from the soil and uses a catalyst in a fixed bed to catalytically purify them, thus overcoming the drawback of extremely high energy consumption in ex-situ thermal desorption. Based on the designed inner and outer double-layer fixed bed and airtight design, it avoids the large carbon emissions caused by thermal desorption.

[0047] Thirdly, the rotary gas lifting furnace of the present invention adopts an airtight design for both the inlet and outlet. The inlet uses an inclined pipe to allow the baffle to open in one direction, ensuring that the soil can enter while preventing gas leakage. The combination of the spring and the baffle at the outlet can compact the soil at the outlet to enhance its airtightness.

[0048] Fourth, this invention employs an oxygen content maintenance design, utilizing a ventilation system composed of a ball valve and a butterfly check valve to automatically and periodically maintain a stable oxygen content. By controlling the automatic opening and closing of the two ball valves and the butterfly check valve under the action of pressure difference, the ventilation process is ensured to proceed smoothly and efficiently.

[0049] In summary, this invention is more efficient, less costly, energy-saving, and environmentally friendly in treating soil contaminated with organic matter, and plays an important role in promoting my country's energy conservation, emission reduction, soil remediation, and dual-carbon strategy. Attached Figure Description

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] Figure 1This is a schematic diagram of the organic polluted soil remediation system in Example 1;

[0052] Figure 2 This is a schematic diagram of the rotary airlift assembly in Example 1;

[0053] Figure 3 This is a schematic diagram of the internal structure of the rotary airlift assembly in Example 1;

[0054] Figure 4 This is a schematic diagram of the fixed bed assembly in Example 1;

[0055] Figure 5 This is a schematic diagram of the butterfly check valve in Example 1;

[0056] Figure 6 This is a schematic diagram of the process for treating organic polluted soil in Example 2.

[0057] Numbering on the map:

[0058] 1-Centrifugal compression assembly; 2-Heating assembly; 3-Rotary airlift assembly; 4-Cyclone separator assembly; 5-Fixed bed assembly; 6-1 Ball valve I; 6-2 Ball valve II; 7-Butterfly check valve;

[0059] 3-1 Soil inlet; 3-2 Air inlet; 3-3 Soil outlet; 3-4 Drive motor; 3-5 Air outlet; 3-6 Sealing baffle; 3-7 Exhaust pipe; 3-8 Spring baffle; 3-9 Feeding screw;

[0060] 5-1 Inlet; 5-2 Top opening; 5-3 Middle layer; 5-4 Bottom opening; 5-5 Outlet; 5-6 Detector; 5-7 Inner layer;

[0061] 7-1 Fixed baffle; 7-2 Opening and closing baffle; 7-3 Rotating shaft. Detailed Implementation

[0062] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0063] Example 1

[0064] Reference Figure 1 A synergistic fixed-bed organic contaminated soil remediation system based on ex-situ SVE technology, including

[0065] The centrifugal compression assembly 1, heating assembly 2, rotary air lifting assembly 3, cyclone separation assembly 4, fixed bed assembly 5, and ventilation assembly are sequentially connected and arranged in a closed loop.

[0066] This system is designed as a closed-loop, recyclable process, which facilitates the circulation and full utilization of heat and oxygen, and ensures the thorough catalytic purification of organic waste gas. Specifically:

[0067] The centrifugal compression assembly 1 and heating assembly 2 are used to pressurize and heat the air drawn in from the outside and circulate it to the bottom of the rotary airlift assembly 3. In this embodiment, the centrifugal compression assembly 1 is a centrifugal compressor, and the heating assembly 2 is a heater. When the centrifugal compressor is started, the butterfly check valve 7 will automatically open under the action of air pressure. At this time, the system draws in air from the outside, and the drawn-in gas passes through the centrifugal compressor and the heater for heating and pressurization. When the air pressure in the system reaches a certain value, the check valve will automatically close, and the internal gas will enter circulation.

[0068] The high-temperature, high-pressure gas then enters the rotary airlift assembly 3. (Refer to...) Figure 2 , Figure 3 The rotary airlift assembly 3 is used to carry out organic pollutants in the contaminated soil with high temperature and high pressure air to purify the soil. It mainly includes a rotary chamber and soil inlet 3-1, soil outlet 3-3, air inlet 3-2, and air outlet 3-5 set at various parts of its shell. The rotary chamber is equipped with a feeding screw 3-9 for stirring and transporting the soil.

[0069] In this embodiment, the soil inlet 3-1 and soil outlet 3-3 are located diagonally opposite to the rotary chamber, with the soil inlet 3-1 positioned at a higher elevation. The soil inlet 3-1 is connected to a soil inlet pipe, which is inclined inwards. A sealing baffle 3-6 is installed inside the pipe. When the sealing baffle 3-6 is hanging naturally, its lower end abuts against the bottom of the pipe. This design facilitates the sliding of contaminated soil into the rotary gas lifter. Furthermore, when no soil is being introduced, the high-pressure gas inside the inlet 3-1 can only rotate inwards, as the pipe is inclined and the sealing baffle 3-6 cannot be opened outwards, thus ensuring the airtightness of the soil inlet 3-1. A spring baffle 3-8 is installed at the soil outlet 3-3. When soil in the rotary chamber attempts to exit, it is blocked by the spring force, which further compacts the soil, reducing gaps between soil particles and minimizing gas leakage.

[0070] In this embodiment, the air inlet 3-2 is located at the bottom of the soil inlet 3-1 side of the rotary chamber, and the air outlet 3-5 is located at the top of the rotary chamber. The air inlet 3-2 is connected to multiple exhaust pipes 3-7 located at the bottom of the rotary chamber. Each exhaust pipe 3-7 has a row of exhaust holes. When high-temperature and high-pressure air enters the rotary gas lifter, it is ejected at high speed from the exhaust holes, passes through the soil cracks, and comes into full contact with the soil during soil disturbance, carrying away volatile organic pollutants and some dust from the soil.

[0071] The mixed gas is then transported to a cyclone separator for dust removal. When the mixed gas exits the rotary gas lifter, it may carry some dust. If this dust enters the fixed bed assembly 5, it will cause the catalyst to be covered or coated with dust, thus reducing the contact area between the catalyst and the gas, lowering catalytic efficiency, and even stopping the catalytic reaction. Therefore, it is necessary to send the mixed gas to a cyclone separator for dust removal.

[0072] The mixed gas after dust removal enters the fixed bed assembly 5. In this embodiment, the fixed bed assembly 5 employs a double-layer fixed bed, as shown in the reference... Figure 4 The double-layer fixed bed is used to purify organic pollutants and fix carbon, and includes a flow area, a catalytic purification area and a carbon fixation area arranged from the outside to the inside. The areas are connected in sequence and nested.

[0073] The flow area receives gas from the upper inlet 5-1. After entering the device, the gas flows along the outer layer to the bottom and then through the bottom hole 5-4 leading to the middle layer 5-3, entering the catalytic purification zone of the middle layer 5-3. The catalytic purification zone contains multiple layers of filter cake, each embedded with an oxidation catalyst. After catalysis, the mixed gas passes through the top hole 5-2 of the middle layer 5-3 and then into the carbon fixation zone of the inner layer 5-7. The carbon fixation zone also contains multiple layers of filter cake. Because the catalytic reaction in the middle layer 5-3 consumes oxygen and produces a large amount of carbon dioxide, a catalyst capable of fixing carbon dioxide is placed on the multiple layers of filter cake in this zone to maintain the carbon dioxide content at or below the level of air, preventing gas from escaping during the ventilation process and exacerbating the greenhouse effect. In other words, the mixed gas passes through the outer layer, middle layer 5-3, and inner layer 5-7 sequentially via a double-layer fixed bed, achieving the removal of organic pollutants and the fixation of carbon dioxide, resulting in a single cycle of purified gas.

[0074] In the preferred embodiment, the bottom of the fixed bed assembly 5 is equipped with multiple detectors 5-6 capable of real-time monitoring of the internal temperature, pressure, oxygen concentration, and concentrations of organic pollutants such as VOCs and SVOCs. The detectors 5-6 can transmit data to a mobile device, such as a smartphone, via a Bluetooth communication module, allowing the operator to actively control the rotational speed of the screw and the internal temperature, pressure, and ventilation process based on real-time data feedback.

[0075] In this soil remediation system, the ventilation component is a crucial element ensuring the stable and smooth operation of the purification and remediation process. In the middle layer (5-3) of the double-layer fixed bed, organic compounds react with oxygen under the action of a catalyst to produce water and carbon dioxide. The carbon dioxide level decreases under the influence of the catalyst in the inner layer (5-7), while oxygen is continuously consumed. When the oxygen concentration drops below 200 ppm, the reaction process slows significantly. If oxygen is not replenished, the reaction will cease. Therefore, a ventilation component is needed to replenish oxygen.

[0076] In this embodiment, the ventilation assembly includes a ball valve I6-1, a ball valve II6-2, and a check valve. The ball valve II6-2 is connected to the exhaust port of the fixed bed assembly 5 and the intake port of the centrifugal compression assembly 1 to form a closed loop. The ball valve I6-1 is located on the branch between the ball valve II6-2 and the exhaust port, and the check valve is located on the branch between the ball valve II6-2 and the intake port.

[0077] When ventilation is required, soil intake is stopped. When the concentration of organic pollutants around the bottom outlet 5-5 of the fixed bed assembly 5 in the system reaches below 50 mg / Kg, the ball valve II6-2 is closed and the ball valve I6-1 is opened to allow the purified gas to be discharged through the ball valve I6-1. At the same time, the pressure difference generated by the decrease in air pressure in the system will cause the check valve to open automatically, and the centrifugal compression assembly 1 will draw in fresh air from the outside.

[0078] When the oxygen content around the bottom outlet 5-5 of the fixed bed assembly 5 in the system rises back to above 20%, the ball valve I6-1 is closed and the ball valve II6-2 is opened. The increased gas pressure inside the system will create a pressure difference, causing the check valve to close automatically, and then the gas will re-enter the circulation.

[0079] In a preferred embodiment, refer to Figure 5 The butterfly check valve 7 includes an opening and closing baffle 7-2 that is automatically opened and closed under air pressure control and a fixed baffle 7-1 that cooperates with it. When the pipeline where the check valve is located is under negative pressure, the opening and closing baffle 7-2 rotates around the rotating shaft 7-3 to open. When the pipeline where the check valve is located is under positive pressure, the opening and closing baffle 7-2 rotates to be tightly attached to the fixed baffle 7-1 to seal and close.

[0080] In an optional embodiment, the oxidation catalyst is a known encapsulated bimetallic Rh-Mn cluster catalyst, which, when raised to a specific temperature, catalyzes the reaction of organic pollutants such as VOCs and SVOCs with oxygen to generate carbon dioxide and water, thereby purifying organic pollutants.

[0081] In an optional embodiment, the carbon fixation catalyst is a zirconium oxide or alumina-based molecular sieve catalyst, whose microporous structure has the ability to selectively adsorb carbon dioxide molecules to maintain the carbon dioxide content at a level comparable to or lower than that in the air, thereby preventing the gas from being released from the device during the ventilation process and thus exacerbating the greenhouse effect.

[0082] Example 2

[0083] Organic soil remediation technology based on ex-situ SVE, referring to Figure 6 ,include

[0084] Keep ball valve I6-1 closed and ball valve II6-2 open;

[0085] Start the centrifugal compressor assembly 1, and use the pressure it generates to open the check valve and draw in air from the outside. When the pressure inside the system reaches a certain value, the check valve will automatically close and the internal gas will enter circulation.

[0086] The inhaled gas is heated and pressurized by passing through the centrifugal compression component 1 and the heating component 2. The high-temperature and high-pressure air generated then enters the rotary airlift component 3 and is ejected at high speed from its bottom. It passes through the cracks in the contaminated soil, comes into full contact with it, and carries away the volatile organic pollutants and some dust in the soil.

[0087] The mixed gas is then sent to the cyclone separator 4 for dust removal. After dust removal, the mixed gas enters the fixed bed assembly 5 and passes through its outer layer, middle layer 5-3 and inner layer 5-7 to remove organic pollutants and fix carbon dioxide, respectively.

[0088] The internal gas re-enters the circulation;

[0089] After repeated cycles, when the concentration of VOCs and SVOCs in the purified gas is less than 50 mg / kg, keep ball valve I6-1 in the open state and ball valve II6-2 in the closed state to discharge the purified gas.

[0090] As an optimization of the above embodiment, after multiple cycles, when the oxygen concentration in the system drops below the set 200ppm, the system will automatically exchange air through the ventilation component to replenish the required oxygen in a timely manner.

[0091] When ventilation is required, soil intake is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / kg, the ball valve II6-2 is closed and the ball valve I6-1 is opened, allowing the purified gas to be discharged through the ball valve I6-1. At the same time, the pressure difference generated by the decrease in gas pressure inside the system causes the check valve to open automatically, and the centrifugal compression component 1 draws in fresh air from the outside.

[0092] When the oxygen content in the system rises back to above 20%, the ball valve I6-1 is closed and the ball valve II6-2 is opened. The increased gas pressure inside the system creates a pressure difference, causing the check valve to close automatically, and then the gas re-enters the circulation.

[0093] Application examples

[0094] Before contaminated soil carrying VOCs / SVOCs enters the rotary stripping furnace, the soil particle size needs to be less than 2 mesh, and the particle size needs to be 5m. 3 It is fed into the rotary gas stripping furnace at a rate of / h.

[0095] High-temperature hot air with a pressure greater than 1 MPa and a temperature of 200~220℃ is pumped at a speed of 10m. 3 The material is fed into the exhaust pipe 3-7 of the rotary gas lifter at a rate of / h. At the same time, the feeding screw 3-9 is driven by the drive motor 3-4 to continuously feed the material. The agitation makes the soil evenly distributed in the rotary gas lifter until the pollution concentration of the contaminated soil reaches the design purification standard. The material is then passed to the cyclone separator through the gas outlet 3-5.

[0096] The mixed gas is separated by a cyclone separator to remove some large dust particles. The remaining mixed gas passes through the outer, middle 5-3, and inner 5-7 (three-layer passages) of a double-layer fixed bed (double-walled) to remove organic waste gas and CO2. After multiple cycles, the concentration of VOCs and SVOCs in the purified gas is less than 50 mg / kg, meeting the emission requirements.

[0097] After multiple cycles, the oxygen concentration participating in the redox reaction will gradually decrease. When it falls below the set value of 200 ppm, the system will automatically exchange air through the ventilation components to replenish the required oxygen in a timely manner.

[0098] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A soil remediation technology for organic polluted soil based on ex-situ SVE, characterized in that: include Keep ball valve I closed and ball valve II open; Start the centrifugal compressor assembly, and use the pressure it generates to open the check valve and draw in air from the outside. When the pressure inside the system reaches a certain value, the check valve automatically closes, and the internal gas enters the circulation. The inhaled gas is heated and pressurized by passing through the centrifugal compression component and the heating component. The resulting high-temperature and high-pressure air enters the rotary airlift component and is ejected at high speed from the bottom. It passes through the cracks in the contaminated soil, comes into full contact with it, and carries away the volatile organic pollutants and some dust in the soil. The mixed gas is then sent to the cyclone separator for dust removal. After dust removal, the mixed gas enters the fixed bed assembly and passes through its outer, middle and inner layers to remove organic pollutants and fix carbon dioxide, respectively. The internal gas re-enters the circulation; When ventilation is required, soil intake is stopped. When the concentration of organic pollutants inside the system reaches below the set value, the ball valve II is closed and the ball valve I is opened, allowing the purified gas to be discharged through the ball valve I. At the same time, the air pressure inside the system decreases, creating a pressure difference, and the check valve opens automatically. The centrifugal compression component draws in fresh air from the outside. When the oxygen content in the system rises back above the set value, the ball valve I is closed and the ball valve II is opened. The internal gas pressure rises, creating a pressure difference. The check valve closes automatically, and the gas then re-enters the circulation. After multiple cycles, when the oxygen concentration in the system drops below the set value, the system will automatically exchange air through the ventilation components to replenish the required oxygen in a timely manner.

2. An organic contaminated soil remediation system based on ex-situ SVE, characterized in that: The system is used to implement the organic contaminated soil remediation process based on ex-situ SVE as described in claim 1, including... The centrifugal compression assembly, heating assembly, rotary air lifting assembly, cyclone separation assembly, fixed bed assembly, and air exchange assembly are connected in sequence. The centrifugal compression assembly and heating assembly are used to pressurize and heat the air drawn in from the outside and pass it to the rotary airlift assembly; The rotary airlift assembly is used to carry out organic pollutants in contaminated soil using high-temperature and high-pressure air. It includes a rotary chamber and soil inlets, soil outlets, air inlets, and air outlets located at various points on the chamber. The rotary chamber is equipped with components for stirring and transporting the soil. The cyclone separator is used for dust removal from the exhaust gas of the rotary airlift assembly; The fixed bed assembly is used to purify organic pollutants and fix carbon, including a flow area, a catalytic purification area and a carbon fixation area arranged from the outside to the inside. The areas are connected in sequence and nested. The catalytic purification area is provided with multiple layers of filter cake, and the filter cake is embedded with an oxidation catalyst. The carbon fixation area is provided with multiple layers of filter cake, and the filter cake is embedded with a carbon fixation catalyst. The ventilation assembly includes a ball valve I, a ball valve II, and a check valve. The ball valve II is connected to the exhaust port of the fixed bed assembly and the intake port of the centrifugal compression assembly. The ball valve I is located on the branch between the ball valve II and the exhaust port, and the check valve is located on the branch between the ball valve II and the intake port. The check valve includes an opening and closing baffle that is automatically opened and closed under air pressure control and a fixed baffle that cooperates with it. When the pipeline where the check valve is located is under negative pressure, the opening and closing baffle rotates to open. When the pipeline where the check valve is located is under positive pressure, the opening and closing baffle rotates to fit tightly against the fixed baffle to seal and close.

3. The organic polluted soil remediation system according to claim 2, characterized in that: The soil inlet and outlet are located diagonally opposite to the rotary cavity, with the soil inlet at a higher position. The air inlet is located at the bottom of the soil inlet side of the rotary cavity, and the air outlet is located at the top of the rotary cavity; The air inlet is connected to an exhaust pipe located at the bottom of the rotating chamber. The exhaust pipe has an exhaust hole to eject high-temperature and high-pressure gas.

4. The organic polluted soil remediation system according to claim 2, characterized in that: The inlet is connected to an inlet pipe, which is inclined inward and has a sealing baffle installed inside. When the sealing baffle is hanging down in its natural state, its lower end abuts against the bottom of the pipe. A spring baffle is installed at the soil outlet.

5. The organic polluted soil remediation system according to claim 2, characterized in that: The oxidation catalyst is an encapsulated bimetallic Rh-Mn cluster catalyst; The carbon fixation catalyst is a zirconium oxide or alumina-based molecular sieve catalyst.

6. The organic polluted soil remediation system according to claim 2, characterized in that: The bottom of the fixed bed assembly is equipped with a detector for real-time monitoring of the internal temperature, pressure, oxygen concentration, and organic pollutant concentration of the system. The detector transmits data to the mobile device via a Bluetooth communication module.

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