Organic matter contaminated soil treatment system based on ectopic SVE
By adopting an organic polluted soil treatment system based on ectopic SVE in the field of soil treatment, using high temperature and high pressure air to extract and purify organic pollutants in the soil, and purify and fix carbon through catalysts and carbon sequestration catalysts, the problems of high cost of installation, limited soil type and harm to the atmospheric environment in the prior art are solved, and efficient and low-cost soil and atmospheric environment purification are achieved.
Patent Information
- Application Number
- CN202421839593.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-07-31
AI Technical Summary
When the prior art deals with soil contaminated by volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) in the treatment of soil contaminated, there are problems such as high cost of the device, limited soil type, and the harm of the purification process to the atmospheric environment.
The organic polluted soil treatment system based on ectopic SVE (thermal desorption) is adopted. The system includes centrifugal compression components, heating components, gyrogenic gas extraction components, cyclone separation components, fixed bed components and ventilation components. Organic pollutants in the soil are extracted and purified by high temperature and high pressure air, and purified and carbon sequestered treatment is carried out using catalysts and carbon sequestered catalysts.
The system can effectively deal with soil polluted by a variety of organic matter, reduce energy consumption and cost, improve the treatment effect, realize the dual purification of soil and atmospheric environment, and avoid pollution to the atmospheric environment in the original technology.
Smart Images
Figure CN222985227U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of soil treatment, specifically to the treatment of soil polluted by volatile organic compounds (VOCs) and some semi-volatile organic compounds (SVOCs), and particularly to an organic-polluted soil treatment system based on ex-situ SVE.
[0002] Background Technique
[0003] Volatile organic compounds such as VOCs and SVOCs are the main pollutants in the atmosphere. These pollutants will not only cause frequent haze weather, damage to the ozone layer, and participate in atmospheric reactions to cause acid rain and other environmental impacts, but also because these organic compounds have extremely high irritation, carcinogenicity, and teratogenic effects. As they volatilize and enter the human body, they will pose a great health threat.
[0004] Today, with the increasing attention of people to the environment.
[0005] For organic pollutants such as VOCs and SVOCs in polluted soil, there are currently four common soil treatment technologies, namely soil washing method, ex-situ thermal desorption method, soil vapor extraction method, and microbial treatment method.
[0006] The soil washing method refers to the use of a specific eluent to deeply wash the polluted soil, which is suitable for treating the unsaturated zone of soil pollution with good permeability and uniformity. By separating and purifying the eluent, recycling integration is realized, the purpose of removing pollutants in the soil is achieved, and finally the pollutants are safely disposed of and the soil is repaired.
[0007] The ex-situ thermal desorption method refers to the process of heating the organic pollutants in the soil with changed position to a sufficient temperature under vacuum conditions or when introducing a carrier gas through direct or indirect heat exchange, so that the volatile organic pollutants can volatilize or separate from the polluted medium and enter the gas treatment system; that is, the ex-situ SVE technology described in this application.
[0008] The in-situ soil vapor extraction method refers to a process of using a special underground extraction (well) system to force the gas in the unsaturated zone soil to flow by using the pressure generated by vacuum pumping or air injection, so as to remove the volatile and semi-volatile organic pollutants therein and achieve the purpose of cleaning the soil.
[0009] The microbial treatment method refers to a remediation technology that uses indigenous microorganisms 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 metabolic functions under suitable environmental conditions, with low cost and less impact on human health, soil, and the environment.
[0010] However, the aforementioned existing methods for treating organic matter - polluted soil all inevitably have serious defects such as relatively high equipment costs, relatively limited types of soil that can be treated, or harm to the atmospheric environment during the process of purifying the soil. Summary of the Utility Model
[0011] In order to overcome the above - mentioned deficiencies, the present utility model provides an organic matter - polluted soil treatment system based on ex - situ SVE.
[0012] The present utility model can effectively treat various organic matter - polluted soils. Also, since the consumable is air and the gas can be recycled, the energy consumption and cost will be greatly reduced. The present utility model makes up for the collective shortcomings of the four common treatment methods, reduces energy consumption and cost, improves the treatment effect, and realizes the complementary advantages of the original methods.
[0013] The technical solution adopted by the present utility model to solve its technical problems is as follows:
[0014] An organic matter - polluted soil treatment system based on ex - situ SVE, including
[0015] A centrifugal compression component, a heating component, a rotary air - lifting component, a cyclone separation component, a fixed - bed component, and a ventilation component that are connected in sequence;
[0016] The centrifugal compression component and the heating component are used to pressurize and heat the air inhaled from the outside and lead it to the bottom of the rotary air - lifting component;
[0017] The rotary air - lifting component is used to carry out the organic pollutants in the polluted soil therein by means of high - temperature and high - pressure air and thus purify the soil. It includes a rotary cavity and soil inlet, soil outlet, air inlet, and air outlet provided at various parts thereof. A spiral member for agitating and transporting soil is installed in the rotary cavity;
[0018] The cyclone separation component is used for dust removal of the air discharged from the rotary air - lifting component;
[0019] The fixed - bed component is used for purifying organic pollutants and carbon sequestration. It includes a circulation area, a catalytic purification area, and a carbon sequestration area arranged from outside to inside. Each area is connected in sequence and nested. The circulation area intakes air from the upper end and is connected to the catalytic purification area at the bottom. Multiple filter cakes are arranged in the catalytic purification area, and oxidation catalysts are inlaid in the filter cakes. The purified mixed gas passes through the top of the catalytic purification area and enters the carbon sequestration area. Multiple filter cakes are arranged in the carbon sequestration area, and carbon sequestration catalysts are inlaid in the filter cakes;
[0020] The ventilation component includes a spherical valve I, a spherical valve II, and a check valve. The spherical valve II is connected to the exhaust port of the fixed bed component and the suction port of the centrifugal compression component. The spherical valve I is arranged on the branch path between the spherical valve II and the exhaust port, and the check valve is arranged on the branch path between the spherical valve II and the suction port.
[0021] As an improvement of the above technical solution, when ventilation is required, the soil feeding is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / Kg, the spherical valve II is closed, and the spherical valve I is opened to discharge the purified gas through the spherical valve I. At the same time, the air pressure inside the system decreases to generate a pressure difference, causing the check valve to open automatically, and the centrifugal compression component sucks in fresh air from the outside.
[0022] When the oxygen content inside the system rises back above 20%, the spherical valve I is closed, and the spherical valve II is opened. The air pressure inside the system increases to generate a pressure difference, causing the check valve to close automatically, and then the gas enters the cycle again.
[0023] As an improvement of the above technical solution, the check valve includes an opening and closing baffle that is automatically opened and closed by air pressure 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 closely adhere to the fixed baffle for sealing and closing.
[0024] As an improvement of the above technical solution, the soil inlet and the soil outlet are arranged in the diagonal direction of the rotary cavity, and the soil inlet is located at a higher position.
[0025] The air inlet is arranged at the bottom on one side of the soil inlet of the rotary cavity, and the air outlet is arranged at the top of the rotary cavity.
[0026] The air inlet is connected to an exhaust pipe arranged at the bottom of the rotary cavity. Exhaust holes are opened on the exhaust pipe to eject high-temperature and high-pressure gas.
[0027] The soil inlet is connected to a soil inlet pipe. The soil inlet pipe is inclined inward. A sealing baffle is installed inside its pipeline. When the sealing baffle hangs naturally, its lower end abuts against the bottom of the pipeline to seal the pipeline.
[0028] A spring baffle is installed at the soil outlet.
[0029] As an improvement of the above technical solution, the oxidation catalyst is an encapsulated bimetallic Rh-Mn cluster catalyst. When it is heated to a specific temperature, it catalyzes the reaction of organic pollutants such as VOCs and SVOCs with oxygen to generate carbon dioxide and water, thereby achieving the purification of organic pollutants.
[0030] The carbon fixation catalyst uses a zirconia 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 equivalent to or lower than that in the air, preventing the gas in the device from being discharged during the ventilation process and exacerbating the greenhouse effect.
[0031] As an improvement to the above technical solution, a detector capable of real-time monitoring of the internal temperature, pressure, oxygen concentration, and the concentration of organic pollutants such as VOCs is provided at the bottom of the fixed bed assembly;
[0032] The detector transmits data to the mobile terminal through a Bluetooth communication module for the detector to control the rotation speed of the spiral member and the internal temperature, air pressure, and ventilation process of the system according to the real-time data feedback.
[0033] To achieve the purpose of the utility model, the following technical solutions are also provided:
[0034] An organic matter contaminated soil treatment process based on off-site SVE includes
[0035] Keep the spherical valve I closed and the spherical valve II open;
[0036] Start the centrifugal compression assembly, use the pressure generated by it to open the check valve, and suck in air from the outside. When the pressure in the system reaches a certain value, the check valve automatically closes and the internal gas enters the cycle;
[0037] The sucked-in gas passes through the centrifugal compression assembly and the heating assembly for heating and pressurization in sequence. Subsequently, the generated high-temperature and high-pressure air enters the rotary air-lifting assembly and sprays out from its bottom at high speed, passes through the gaps in the contaminated soil, makes full contact with it, and takes away the volatile organic pollutants and part of the dust in the soil;
[0038] Subsequently, the mixed gas is sent to the cyclone separation assembly for dust removal operation. After dust removal, the mixed gas enters the fixed bed assembly and passes through its outer layer, middle layer, and inner layer in sequence to remove organic pollutants and fix carbon dioxide respectively;
[0039] The internal gas enters the cycle again;
[0040] After circulating multiple times, when the concentrations of VOCs and SVOCs in the purified gas are less than 50 mg / kg, keep the spherical valve I open and the spherical valve II closed, and discharge the purified gas.
[0041] As an improvement to the above technical solution, after circulating multiple times, when the oxygen concentration in the system drops below the set 200 ppm, the system will automatically ventilate through the ventilation component to timely supplement the required oxygen.
[0042] As an improvement of the above technical solution, when ventilation is required, soil feeding is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / Kg, the spherical valve II is closed, and the spherical valve I is opened to discharge the purified gas through the spherical valve I. At the same time, the air pressure inside the system decreases to generate a pressure difference, causing the check valve to open automatically, and the centrifugal compression assembly inhales fresh air from the outside.
[0043] When the oxygen content inside the system rises back above 20%, the spherical valve I is closed, and the spherical valve II is opened. The air pressure inside the system increases to generate a pressure difference, causing the check valve to close automatically, and then the gas enters the cycle again.
[0044] Beneficial effects brought by the present utility model:
[0045] The present utility model innovatively proposes a system for treating organic pollutant-contaminated soil based on off-site air stripping SVE, realizing the organic combination and complementary advantages of soil air stripping and thermal desorption methods, making the process flow for treating contaminated soil more concise, convenient, with less environmental pollution, energy-saving, efficient, and low-cost.
[0046] Firstly, through off-site treatment of the soil, the present utility model makes up for the disadvantages of in-situ soil air stripping method, such as the need to spend a large amount of money to purchase ozone and the pollution caused by the organic waste gas separated from the soil entering the atmosphere. The process flow is designed in a closed loop, which is beneficial to the circulation and full use of heat and oxygen, and can also fully catalytically purify the organic waste gas. After the gas passes through the fixed bed, it will carry part of the waste heat into the next cycle, making full use of the heat generated by the heater to achieve the effect of energy saving.
[0047] Secondly, through the air stripping system, the present utility model separates organic pollutants from the soil and catalytically purifies them using the catalyst in the fixed bed, making up for the disadvantage of extremely high energy consumption of off-site thermal desorption. Based on the designed inner and outer double-layer fixed bed and airtight design, it avoids the defect of large carbon emissions caused by the thermal desorption method.
[0048] Thirdly, both the inlet and outlet of the rotary air stripping furnace of the present utility model adopt airtight designs. The soil inlet uses an inclined pipe to make the baffle open unidirectionally, ensuring that soil can enter while preventing gas leakage. The combination of the spring and the baffle at the soil outlet can compact the soil at the outlet to enhance its airtightness.
[0049] Fourthly, the present utility model adopts an oxygen content maintenance design, and uses a ventilation system composed of a spherical valve and a butterfly check valve to automatically and regularly maintain the stability of the oxygen content. By controlling the automatic opening and closing of the two spherical valves and the butterfly check valve under the action of the pressure difference, it ensures that the ventilation process is smooth and efficient. Description of the Drawings
[0050] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0051] Figure 1 It is a schematic structural diagram of the organic contaminated soil treatment system in Embodiment 1;
[0052] Figure 2 It is a schematic structural diagram of the rotary air-lift assembly in Embodiment 1;
[0053] Figure 3 It is a schematic internal structure diagram of the rotary air-lift assembly in Embodiment 1;
[0054] Figure 4 It is a schematic structural diagram of the fixed bed assembly in Embodiment 1;
[0055] Figure 5 It is a schematic structural diagram of the butterfly check valve in Embodiment 1;
[0056] Figure 6 It is a schematic process flow diagram of the organic contaminated soil treatment process in Embodiment 2.
[0057] Reference numerals in the figure:
[0058] 1 - Centrifugal compression assembly; 2 - Heating assembly; 3 - Rotary air-lift assembly; 4 - Cyclone separation assembly; 5 - Fixed bed assembly; 6-1 Globe valve I; 6-2 Globe valve II; 7 - Butterfly check valve;
[0059] 3-1 Soil entry port; 3-2 Air inlet; 3-3 Soil exit port; 3-4 Driving motor; 3-5 Air outlet; 3-6 Sealing baffle; 3-7 Exhaust pipe; 3-8 Spring baffle; 3-9 Feeding screw;
[0060] 5-1 Air inlet end; 5-2 Top hole; 5-3 Middle layer; 5-4 Bottom hole; 5-5 Air outlet end; 5-6 Detector; 5-7 Inner layer;
[0061] 7-1 Fixed baffle, 7-2 Opening and closing baffle; 7-3 Rotating shaft. Specific embodiments
[0062] The technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.
[0063] Embodiment 1
[0064] Refer to Figure 1, a collaborative fixed-bed organic pollutant soil treatment system based on the off-site SVE technology, comprising
[0065] a centrifugal compression component 1, a heating component 2, a rotary air-lifting component 3, a cyclone separation component 4, a fixed-bed component 5 and a ventilation component that are connected in sequence and arranged in a closed loop.
[0066] The process flow of this system is designed to be a closed-loop and recyclable type, which is not only conducive to the circulation and full use of heat and oxygen, but also enables the organic waste gas to be fully catalytically purified. Specifically:
[0067] The centrifugal compression component 1 and the heating component 2 are used to pressurize and heat the air inhaled from the outside and lead it to the bottom of the rotary air-lifting component 3. In this embodiment, the centrifugal compression component 1 adopts a centrifugal compressor, and the heating component 2 adopts 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 inhales air from the outside, and the inhaled gas is heated and pressurized by passing through the centrifugal compressor and the heater in sequence. When the air pressure in the system reaches a certain value, the check valve will automatically close, and the internal gas enters the circulation.
[0068] The high-temperature and high-pressure gas then enters the rotary air-lifting component 3. Refer to Figure 2 , Figure 3 , the rotary air-lifting component 3 is used to carry out the organic pollutants in the polluted soil therein by means of high-temperature and high-pressure air and thus purify the soil. It mainly includes a rotary cavity and an earth inlet 3-1, an earth outlet 3-3, an air inlet 3-2 and an air outlet 3-5 arranged at various places on its shell. A feeding screw member 3-9 for agitating and transporting the soil is installed in the rotary cavity.
[0069] In this embodiment, the earth inlet 3-1 and the earth outlet 3-3 are arranged in the diagonal direction of the rotary cavity, and the earth inlet 3-1 is located at a high place. The earth inlet 3-1 is connected to an earth inlet pipe, and this earth inlet pipe is arranged to incline inward, and a sealing baffle 3-6 is installed in its pipeline. When the sealing baffle 3-6 hangs down in the natural state, its lower end abuts against the bottom of the pipeline. This design facilitates the sliding of the polluted soil into the rotary air-lifting furnace on the one hand, and on the other hand, when there is no soil entering, the high-pressure gas inside wants to be discharged from the earth inlet 3-1. Due to the inclination of the pipeline and the fact that the sealing baffle 3-6 cannot be opened outward and can only rotate unidirectionally inward, the airtightness at the earth inlet 3-1 can be ensured. A spring baffle 3-8 is installed at the earth outlet 3-3. When the soil in the rotary cavity wants to be discharged, it will be blocked by the spring force, and this force will further compact the soil, thereby reducing the gaps between the soils and reducing the gas leakage.
[0070] In this embodiment, the air inlet 3-2 is arranged at the bottom on one side of the soil entry port 3-1 of the rotary cavity, and the air outlet 3-5 is arranged at the top end of the rotary cavity. The air inlet 3-2 is communicated with a plurality of exhaust pipes 3-7 arranged at the bottom of the rotary cavity. A row of exhaust holes are formed in the exhaust pipes 3-7. When the high-temperature and high-pressure air enters the rotary air-lift furnace, it sprays out from the exhaust holes at high speed, passes through the soil gaps, and fully contacts with the soil during the soil disturbance process, taking away the volatile organic pollutants and part of the dust in the soil.
[0071] Subsequently, the mixed gas is transported to a cyclone separator for dust removal operation. Since part of the dust may be carried out when the mixed gas is discharged from the rotary air-lift furnace, if the dust enters the fixed bed assembly 5, it will cause adverse effects such as the catalyst being covered and coated with dust, thereby reducing the contact area between the catalyst and the gas, lowering the catalytic efficiency, and even stopping the catalytic reaction. Therefore, it is necessary to send the mixed gas into the cyclone separator for dust removal.
[0072] The mixed gas after dust removal enters the fixed bed assembly 5. The fixed bed assembly 5 in this embodiment adopts a double-layer fixed bed. Refer to Figure 4 The double-layer fixed bed is used for purifying organic pollutants and carbon sequestration, and includes a circulation area, a catalytic purification area, and a carbon sequestration area arranged from outside to inside. Each area is connected and nested in sequence.
[0073] The circulation area intakes air from the upper air inlet end 5-1. After the gas enters the device, it flows along the outer layer to the bottom of the device, and enters the catalytic purification area of the middle layer 5-3 through the bottom hole 5-4 leading to the bottom of the middle layer 5-3. A plurality of filter cakes are arranged in the catalytic purification area, and oxidation catalysts are embedded in the filter cakes. After catalysis, the mixed gas passes through the top hole 5-2 of the middle layer 5-3 and then enters the inner layer 5-7 carbon sequestration area. A plurality of filter cakes are also arranged in the carbon sequestration area. Since the catalytic reaction in the middle layer 5-3 area consumes oxygen and generates more carbon dioxide, considering the subsequent air exchange process, catalysts capable of fixing carbon dioxide are arranged on the plurality of filter cakes in this area to maintain the carbon dioxide content to be equal to or lower than the carbon dioxide content in the air, preventing the gas in the device from being discharged during the air exchange process and aggravating the greenhouse effect. That is, the mixed gas passes through the double-layer fixed bed successively through the outer layer, the middle layer 5-3, and the inner layer 5-7, respectively achieving the effects of removing organic pollutants and fixing carbon dioxide, and obtaining a primary cycle of purified gas.
[0074] In the best embodiment, the bottom of the fixed bed assembly 5 is provided with a variety of detectors 5-6 capable of real-time monitoring of the temperature, pressure, oxygen concentration, and concentration of organic pollutants such as VOCs and SVOCs in the system. The detectors 5-6 can transmit data to a mobile terminal such as a mobile phone through an existing Bluetooth communication module, so that the detector can actively control the rotation speed of the spiral element and the temperature, air pressure, and ventilation process in the system according to real-time data feedback.
[0075] In this soil treatment system, the ventilation component is an important part to ensure that the purification and treatment process can proceed stably and smoothly. In the middle layer 5-3 area of the double-layer fixed bed, the organic compound reacts with oxygen under the action of the catalyst to produce water and carbon dioxide. The carbon dioxide will reach a lower level under the action of the catalyst in the inner layer 5-7, while the oxygen in the system is continuously consumed. When the oxygen concentration is lower than 200ppm, the reaction process will be greatly reduced. If oxygen continues to not be replenished, the reaction will stop. Therefore, it is necessary to design a ventilation component to replenish oxygen.
[0076] In this embodiment, the ventilation component 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 component 5 and the intake port of the centrifugal compression component 1 to form a closed circulation loop. The ball valve I6-1 is arranged on the branch between the ball valve II6-2 and the exhaust port, and the check valve is arranged on the branch between the ball valve II6-2 and the intake port.
[0077] When ventilation is required, the soil is stopped. When the concentration of organic pollutants around the gas outlet 5-5 at the bottom 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 discharge the purified gas through the ball valve I6-1. At the same time, the pressure in the system is reduced to generate a pressure difference, which will cause the check valve to open automatically, and the centrifugal compression assembly 1 will inhale 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 air pressure inside the system generates a pressure difference, which will cause the check valve to close automatically, and then the gas enters the circulation again.
[0079] In a preferred embodiment, reference Figure 5 The butterfly check valve 7 includes an opening and closing baffle 7-2 which is automatically opened and closed by air pressure control and a fixed baffle 7-1 which 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 fit tightly against the fixed baffle 7-1 to seal and close.
[0080] In an alternative embodiment, the oxidation catalyst is a known encapsulated bimetallic Rh-Mn cluster catalyst, which purifies organic pollutants by catalyzing the reaction of organic pollutants such as VOCs and SVOCs with oxygen to generate carbon dioxide and water when heated to a specific temperature.
[0081] In an alternative embodiment, the carbon fixation catalyst is a zirconia 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 equivalent to or lower than that in the air, preventing the discharge of gas inside the device during the ventilation process and exacerbating the greenhouse effect.
[0082] Example 2
[0083] Applied to the in-situ SVE-based organic contaminated soil remediation process of Example 1, refer to Figure 6 , including
[0084] Keep the spherical valve I6-1 in the closed state and the spherical valve II6-2 in the open state;
[0085] Start the centrifugal compression assembly 1, use the pressure generated by it to open the check valve, and suck 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;
[0086] The sucked-in gas passes through the centrifugal compression assembly 1 and the heating assembly 2 in sequence for heating and pressurization. Subsequently, the high-temperature and high-pressure air generated enters the rotary air-lift assembly 3 and sprays out from its bottom at high speed, passes through the gaps in the contaminated soil, comes into full contact with it, and takes away the volatile organic pollutants and part of the dust in the soil;
[0087] Subsequently, the mixed gas is sent to the cyclone separation assembly 4 for dust removal operation. After dust removal, the mixed gas enters the fixed bed assembly 5, passes through its outer layer, middle layer 5-3, and inner layer 5-7 in sequence, and removes organic pollutants and fixes carbon dioxide respectively;
[0088] The internal gas enters the circulation again;
[0089] After circulating multiple times, when the concentrations of VOCs and SVOCs in the purified gas are less than 50 mg / kg, keep the spherical valve I6-1 in the open state and the spherical valve II6-2 in the closed state, and discharge the purified gas.
[0090] As an optimization of the above embodiment, after circulating multiple times, when the oxygen concentration inside the system drops below the set 200 ppm, the system will automatically ventilate through the ventilation assembly to timely supplement the required oxygen.
[0091] When air change is required, the soil feeding is stopped. When the concentration of organic pollutants inside the system reaches below 50 mg / Kg, the spherical valve II 6-2 is closed, and the spherical valve I 6-1 is opened, so that the purified gas is discharged through the spherical valve I 6-1. At the same time, the air pressure inside the system decreases to generate a pressure difference, causing the check valve to open automatically, and the centrifugal compression assembly 1 sucks fresh air from the outside.
[0092] When the oxygen content inside the system rises back above 20% again, the spherical valve I 6-1 is closed, and the spherical valve II 6-2 is opened. The air pressure inside the system increases to generate a pressure difference, causing the check valve to close automatically, and then the gas enters the cycle again.
[0093] Application Example
[0094] Before the contaminated soil carrying VOCs / SVOCs enters the rotary air stripping furnace, the soil particle size needs to be less than 2 mesh and is fed into the rotary air stripping furnace at a rate of 5 m 3 / h.
[0095] Hot air with a pressure greater than 1 MPa and a temperature of 200 - 220 °C is fed into the exhaust pipe 3-7 inside the rotary air stripping furnace at a rate of 10 m 3 / h. At the same time, the feeding screw 3-9 is continuously fed by the driving motor 3-4, and the stirring makes the soil evenly distributed in the rotary air stripping furnace until the pollution concentration of the contaminated soil reaches the designed purification standard, and then it passes through the air outlet 3-5 to the cyclone separator.
[0096] The mixed gas passes through the cyclone separator to separate some large particle dust carried. The remaining mixed gas passes through the outer layer, middle layer 5-3, and inner layer 5-7 (three-layer passage) of the double-layer fixed bed (double-layer wall) to remove organic waste gas and CO2 respectively. Finally, after multiple cycles, the concentration of VOCs and SVOCs contained 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 is lower than the set 200 ppm, the system will automatically perform air change through the air change component to timely supplement the required oxygen.
[0098] It should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent substitution on some of the technical features. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. The organic matter contaminated soil treatment system based on ex situ SVE is characterized by: include A centrifugal compression component, a heating component, a rotary air stripping component, a cyclone separation component, a fixed bed component and a ventilation component connected in sequence; The centrifugal compression component and the heating component are used to pressurize and heat the air sucked from the outside and pass it to the rotary air stripping component; The rotary air stripping assembly is used to carry out organic pollutants in the contaminated soil with the help of high-temperature and high-pressure air, and includes a rotary chamber and soil inlets, soil outlets, air inlets and air outlets arranged at various locations thereof, and components for stirring and transporting the soil are installed in the rotary chamber; The cyclone separation component is used for dust removal of the outlet gas of the rotary air stripping component; The fixed bed assembly is used to purify organic pollutants and fix carbon, and includes a circulation area, a catalytic purification area and a carbon fixation area arranged from the outside to the inside, and each area is connected and nested in sequence. The circulation area takes in air from the upper end and is connected to the catalytic purification area at the bottom. Multiple layers of filter cakes are arranged in the catalytic purification area, and oxidation catalysts are embedded in the filter cakes. The purified gas passes through the top of the catalytic purification area into the carbon fixation area. Multiple layers of filter cakes are arranged in the carbon fixation area, and carbon fixation catalysts are embedded in the filter cakes. 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 arranged on a branch road between the ball valve II and the exhaust port, and the check valve is arranged on a branch road between the ball valve II and the intake port.
2. The organic matter contaminated soil treatment system according to claim 1 is characterized by: When ventilation is required, when the concentration of organic pollutants in the system reaches below the set value, the ball valve II is closed, the ball valve I is opened, and the purified gas is discharged through the ball valve I. At the same time, the check valve is automatically opened, and the centrifugal compression component inhales fresh air from the outside; When the oxygen content in the system rises back above the set value, the ball valve I is closed, the ball valve II is opened, the check valve is automatically closed, and then the gas enters the circulation again.
3. The organic matter contaminated soil treatment system according to claim 1 or 2, characterized in that: The check valve includes an opening and closing baffle that is automatically opened and closed by 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.
4. The organic matter contaminated soil treatment system according to claim 1 is characterized by: The soil entry and exit are arranged in diagonal directions of the rotary cavity, and the soil entry is located at a high position.
5. The organic matter contaminated soil treatment system according to claim 1 is characterized by: The air inlet is arranged at the bottom of one side of the soil entrance of the rotary chamber, and the air outlet is arranged at the top of the rotary chamber; The air inlet is connected to an exhaust pipe arranged at the bottom of the rotary chamber, and the exhaust pipe is provided with an exhaust hole to eject high-temperature and high-pressure gas.
6. The organic matter contaminated soil treatment system according to claim 1 is characterized by: The soil entry port is connected to a soil entry pipe, which is inclined inwardly, and a sealing baffle is installed in the pipe. When the sealing baffle is drooped in a natural state, the lower end thereof abuts against the bottom of the pipe.
7. The organic matter contaminated soil treatment system according to claim 1 is characterized by: A spring baffle is installed at the unearthing opening.
8. The organic matter contaminated soil treatment system according to claim 1 is characterized by: A detector for real-time monitoring of the internal temperature, pressure, oxygen concentration and organic pollutant concentration of the system is arranged at the bottom of the fixed bed assembly.
9. The organic matter contaminated soil treatment system according to claim 8 is characterized by: The detector transmits data to the mobile terminal via the Bluetooth communication module.