Multi-phase extraction treatment device for volatile organic compounds in soil and underground water

Abstract

The utility model relates to a soil and underground water volatile organic compound multiphase extraction treatment device, and relates to the field of soil and underground water pollution treatment equipment. The device comprises an extraction unit, a rotational flow unit and an intelligent control unit, the extraction unit comprises a gas-phase extraction pipe and a liquid-phase extraction pipe, the gas-phase extraction pipe and the liquid-phase extraction pipe are buried in a polluted soil layer in parallel, and outlets of the gas-phase extraction pipe and the liquid-phase extraction pipe are connected with a composite screen pipe; the gas-phase extraction pipe and the liquid-phase extraction pipe are both connected with the composite sieve pipe in a sealing manner; and the cyclone unit comprises a primary centrifugal separator and a secondary electrostatic coalescer. Through the synergistic effect of the extraction unit, the rotational flow unit and the intelligent control unit, volatile organic compounds in soil and underground water can be efficiently extracted and effectively separated. A gas-phase extraction pipe and a liquid-phase extraction pipe of the extraction unit can extract volatile organic compounds in a gas phase and a liquid phase at the same time, and the extracted substances are preliminarily filtered by a composite screen pipe.

Description

Technical Field

[0001] This application relates to the technical field of soil and groundwater pollution treatment equipment, and in particular to a multiphase extraction and treatment device for volatile organic compounds in soil and groundwater. Background Technology

[0002] Volatile organic compound (VOC) pollution is a major challenge in soil and groundwater remediation, characterized by its high mobility and wide diffusion range. Traditional technologies typically employ single-phase gas or liquid extraction, but actual pollution often presents as a multiphase coexistence (e.g., free phase, dissolved phase, and adsorbed phase). In recent years, multiphase extraction (MPE) technology has gradually become mainstream, simultaneously removing gaseous, liquid, and non-aqueous liquid pollutants from the contaminated area through vacuum extraction. However, existing equipment generally suffers from low system integration, incomplete phase separation, high energy consumption, and poor adaptability to low-permeability soil layers, resulting in long remediation cycles and high costs.

[0003] Existing technologies are mostly divided into the following three types, but each has its own shortcomings:

[0004] Single-phase extraction technology: designed only for gaseous or liquid phase pollutants, such as soil gas phase extraction systems that extract pollutant gases through negative pressure, but ineffective for groundwater pollution, and groundwater extraction and treatment systems cannot treat gaseous pollutants.

[0005] Simple multiphase extraction device: It adopts a gas-liquid mixing extraction pipeline and achieves phase separation through a gas-liquid separator at the back end. However, the separation efficiency is greatly affected by flow rate fluctuations and is prone to secondary pollution.

[0006] The staged extraction system consists of separate gas phase and liquid phase extraction units, requires multiple pump sets, occupies a large area, and has complex collaborative control.

[0007] Regarding the aforementioned technologies, it has been found that existing multiphase extraction and treatment devices for volatile organic compounds in soil and groundwater are prone to "gas lock" or "liquid hammer" during the mixing and transport of gas-liquid two-phase flows, resulting in a decrease in extraction efficiency. Traditional separation devices have poor separation effects on micron-level oil-water emulsions, high subsequent processing loads, and the system lacks adaptive adjustment capabilities. When soil permeability changes, parameters need to be manually intervened, making operation cumbersome. Utility Model Content

[0008] In order to achieve stable gas-liquid two-phase flow, stable mixing, extraction and treatment, and intelligent control system, this application provides a multiphase extraction and treatment device for volatile organic compounds in soil and groundwater.

[0009] The multiphase extraction and treatment device for volatile organic compounds in soil and groundwater provided in this application adopts the following technical solution:

[0010] A multiphase extraction and treatment device for volatile organic compounds in soil and groundwater includes an extraction unit, a cyclone unit, and an intelligent control unit. The extraction unit includes a gas phase extraction tube and a liquid phase extraction tube, which are buried parallel to each other in the contaminated soil layer. The outlets of the gas phase extraction tube and the liquid phase extraction tube are connected to a composite screen tube, and both the gas phase extraction tube and the liquid phase extraction tube are sealed to the composite screen tube. The cyclone unit includes a primary centrifuge and a secondary electrostatic coalescer. The inlet end of the primary centrifuge is connected to the composite screen tube, and the secondary electrostatic coalescer is connected to the gas phase outlet end of the primary centrifuge. The intelligent control unit includes a PLC controller, a pressure sensor, and a variable frequency motor. The pressure sensor is located at the end of the gas phase extraction tube, the end of the liquid phase extraction tube, and the inlet and outlet of the primary centrifuge. The device also includes a vacuum pump that provides negative pressure to the extraction unit, and the variable frequency motor is installed in the vacuum pump.

[0011] By adopting the above technical solution, it is ensured that the drilling reaches the bottom of the contamination layer during use, and then the double pipes of the extraction unit are laid. The substances extracted by the gas phase extraction pipe and the liquid phase extraction pipe are sent to the cyclone unit through the composite screen pipe. The primary centrifugal separator and the secondary electrostatic coalescer in the cyclone unit work together to achieve rapid separation. The intelligent control unit ensures that the variable frequency motor is adjusted in real time according to the pressure sensor, thereby changing the negative pressure of the vacuum pump and achieving the purpose of intelligent adjustment.

[0012] Optionally, the gas extraction tube is made of a stainless steel corrugated tube with a diameter of 50 mm.

[0013] By adopting the above technical solution, the gas phase extraction tube is made of stainless steel corrugated pipe with a diameter of 50mm. Stainless steel is corrosion resistant, and the corrugated pipe has good flexibility, which can adapt to different soil environments, ensure stable gas phase extraction, and improve gas phase extraction efficiency.

[0014] Optionally, the liquid phase extraction tube is made of high-density polyethylene tube with a diameter of 80 mm.

[0015] By adopting the above technical solution, the liquid phase extraction tube is made of high-density polyethylene pipe with a diameter of 80mm. High-density polyethylene pipe has high strength and corrosion resistance, and can effectively extract volatile organic compounds from groundwater, ensuring the liquid phase extraction effect.

[0016] Optionally, the composite screen tube is equipped with several sets of screens, the screens are made of 316L stainless steel sintered filter screens, and the pore size of the screens is 10μm.

[0017] By adopting the above technical solution, a 316L stainless steel sintered filter screen with a pore size of 10μm is installed in the composite screen tube. 316L stainless steel is corrosion resistant, and the sintered filter screen has good filtration performance, which can effectively filter impurities in soil and water, prevent impurities from entering the subsequent treatment unit, and protect the normal operation of the equipment.

[0018] Optionally, hydrophobic activated carbon fiber felt is provided on both sides of the screen, and the hydrophobic activated carbon fiber felt is bonded and fixed to the screen.

[0019] By adopting the above technical solution, hydrophobic activated carbon fiber felt is set on both sides of the screen and adhered and fixed to the screen. The hydrophobic activated carbon fiber felt can adsorb volatile organic compounds, further improving the filtration effect of the composite screen tube and reducing the leakage of volatile organic compounds.

[0020] Optionally, the primary centrifugal separator is a 316L stainless steel cyclone separator with a cone angle of 20°.

[0021] By adopting the above technical solution, the primary centrifugal separator uses a 316L stainless steel cyclone with a cone angle of 20° to perform preliminary gas-liquid separation using centrifugal force. 316L stainless steel is corrosion resistant, and the appropriate cone angle can improve separation efficiency and reduce the load on subsequent processing units.

[0022] Optionally, the secondary electrostatic coalescer uses a titanium alloy electrode assembly with a plate spacing of 15 mm.

[0023] By adopting the above technical solution, the secondary electrostatic coalescer uses a titanium alloy electrode assembly with a plate spacing of 15mm. Titanium alloy has good conductivity and corrosion resistance. The appropriate plate spacing can further separate tiny droplets in the gas phase through electrostatic coalescence, thereby improving the purity of the gas phase.

[0024] Optionally, the pressure sensor has a range of 0-1 MPa, and the variable frequency motor has a power of 5.5 kW.

[0025] By adopting the above technical solution, the pressure sensor has a range of 0-1MPa, the variable frequency motor has a power of 5.5kW, the pressure sensor monitors the system pressure in real time, and the PLC controller controls the speed of the variable frequency motor and adjusts the negative pressure of the vacuum pump according to the pressure data, so as to realize intelligent control and reduce operating costs.

[0026] In summary, this application includes at least one of the following beneficial technical effects: Through the synergistic action of the extraction unit, the cyclone unit, and the intelligent control unit, this application can efficiently extract and effectively separate volatile organic compounds (VOCs) from soil and groundwater. The gas-phase extraction tube and liquid-phase extraction tube of the extraction unit can simultaneously extract VOCs from the gas and liquid phases, while the composite screen tube performs preliminary filtration of the extracted substances. The primary centrifugal separator and secondary electrostatic coalescer of the cyclone unit perform multi-stage gas-liquid separation, improving the separation effect. The intelligent control unit monitors the system pressure in real time through a pressure sensor and uses a PLC controller to control the variable frequency motor to adjust the vacuum pump negative pressure, achieving intelligent operation and reducing energy consumption and operating costs. Simultaneously, all components are made of corrosion-resistant materials, ensuring the service life and stability of the device, and effectively treating VOC pollution in soil and groundwater. Attached Figure Description

[0027] Figure 1 This is a block diagram of the modular structure of the multiphase extraction and treatment device for volatile organic compounds in soil and groundwater according to this application.

[0028] Figure 2 This is a schematic diagram of the overall structure in the embodiments of this application.

[0029] Figure 3 This is a schematic diagram of the structure of the vacuum pump and the variable frequency motor in the embodiment of this application.

[0030] Figure 4 This is a schematic diagram of the composite screen tube in the embodiments of this application.

[0031] Figure 5 yes Figure 4 Front view of the device shown.

[0032] Explanation of reference numerals in the attached drawings: 1. Extraction unit; 11. Gas phase extraction tube; 12. Liquid phase extraction tube; 2. Cyclone unit; 21. Primary centrifuge; 22. Secondary electrostatic coalescer; 3. Intelligent control unit; 31. PLC controller; 32. Pressure sensor; 33. Variable frequency motor; 4. Composite sieve tube; 41. Screen; 42. Hydrophobic activated carbon fiber felt; 5. Vacuum pump. Detailed Implementation

[0033] The present application will be further described in detail below with reference to the accompanying drawings.

[0034] This application discloses a multiphase extraction and treatment device for volatile organic compounds in soil and groundwater. (Refer to...) Figure 1 , Figure 2 and Figure 3As shown, a multiphase extraction and treatment device for volatile organic compounds in soil and groundwater includes an extraction unit 1, a cyclone unit 2, and an intelligent control unit 3. The extraction unit 1 includes a gas phase extraction pipe 11 and a liquid phase extraction pipe 12, which are buried parallel to each other in the contaminated soil layer. The outlets of the gas phase extraction pipe 11 and the liquid phase extraction pipe 12 are connected to a composite screen pipe 4, and both the gas phase extraction pipe 11 and the liquid phase extraction pipe 12 are sealed to the composite screen pipe 4. The cyclone unit 2 includes a primary centrifuge 21 and a secondary centrifuge 22. The first-stage electrostatic coalescer 22 is connected to the inlet end of the first-stage centrifugal separator 21 and the composite sieve tube 4. The second-stage electrostatic coalescer 22 is connected to the gas phase outlet end of the first-stage centrifugal separator 21. The intelligent control unit 3 includes a PLC controller 31, a pressure sensor 32 and a variable frequency motor 33. The pressure sensor 32 is arranged at the end of the gas phase extraction tube 11, the end of the liquid phase extraction tube 12 and the inlet and outlet of the first-stage centrifugal separator 21. It also includes a vacuum pump 5 that provides negative pressure to the extraction unit 1. The variable frequency motor 33 is installed in the vacuum pump 5.

[0035] Reference Figure 1 , Figure 2 and Figure 3 As shown, the gas phase extraction tube 11 is made of a 50mm diameter stainless steel corrugated pipe. Stainless steel is corrosion-resistant, and the corrugated pipe is flexible, adaptable to different soil environments, ensuring stable gas phase extraction and improving extraction efficiency. The gas phase extraction tube 11 is made of SUS304 stainless steel with a wall thickness of 2mm and a pressure rating of PN16. The liquid phase extraction tube 12 is made of an 80mm diameter high-density polyethylene (HDPE) pipe. HDPE pipe is strong and corrosion-resistant, effectively extracting volatile organic compounds from groundwater and ensuring effective liquid phase extraction.

[0036] Reference Figure 4 and Figure 5 As shown, the composite screen tube 4 is equipped with several sets of fine screens 41. The screens 41 are made of 316L stainless steel sintered filter mesh with a pore size of 10μm. The 316L stainless steel sintered filter mesh is corrosion-resistant, and the sintered filter mesh has good filtration performance, effectively filtering impurities from soil and water, preventing impurities from entering subsequent treatment units, and protecting the normal operation of the equipment. Hydrophobic activated carbon fiber felt 42 is provided on both sides of the screens 41, and the hydrophobic activated carbon fiber felt 42 is adhered and fixed to the screens 41. The hydrophobic activated carbon fiber felt 42 can adsorb volatile organic compounds, further improving the filtration effect of the composite screen tube 4 and reducing the leakage of volatile organic compounds.

[0037] Reference Figure 1 and Figure 2 As shown, the primary centrifugal separator 21 uses a 316L stainless steel cyclone separator with a 20° cone angle. The primary centrifugal separator 21 utilizes centrifugal force for initial gas-liquid separation. 316L stainless steel is corrosion-resistant, and the appropriate cone angle improves separation efficiency and reduces the load on subsequent processing units. The secondary electrostatic coalescer 22 uses titanium alloy electrode groups with a 15mm electrode spacing. Titanium alloy has good conductivity and corrosion resistance, and the appropriate electrode spacing allows for further separation of tiny liquid droplets in the gas phase through electrostatic coalescence, improving the purity of the gas phase. The positive electrode of the electrostatic coalescer is made of TA2 titanium with a platinum coating, while the negative electrode is made of 304 stainless steel.

[0038] Reference Figure 2 and Figure 3 As shown, the pressure sensor 32 has a range of 0-1 MPa, and the variable frequency motor 33 has a power of 5.5 kW. The pressure sensor 32 monitors the system pressure in real time, and the PLC controller 31 controls the speed of the variable frequency motor 33 based on the pressure data, adjusting the negative pressure of the vacuum pump 5 to achieve intelligent control and reduce operating costs. The variable frequency motor 33 is a Siemens G120 series, supporting 4-20mA signal input for speed adjustment.

[0039] The implementation principle of the multiphase extraction and treatment device for volatile organic compounds in soil and groundwater according to this application embodiment is as follows: During device installation, the gas phase extraction pipe 11 and the liquid phase extraction pipe 12 are buried parallel to each other in the contaminated soil layer, ensuring that the outlets of the gas phase extraction pipe 11 and the liquid phase extraction pipe 12 are sealed to the composite screen pipe 4. The gas phase extraction pipe 11 is made of stainless steel corrugated pipe with a diameter of 50 mm, and the liquid phase extraction pipe 12 is made of high-density polyethylene pipe with a diameter of 80 mm. The inlet end of the primary centrifuge 21 is connected to the composite screen pipe 4, and the secondary electrostatic coalescer 22 is connected to the gas phase outlet end of the primary centrifuge 21. The primary centrifuge 21 is a 316L stainless steel cyclone separator with a cone angle of 20°, and the secondary electrostatic coalescer 22 is a titanium alloy electrode assembly with an electrode spacing of 15 mm. Pressure sensors 32 are installed at the end of the gas phase extraction tube 11, the end of the liquid phase extraction tube 12, and the inlet and outlet of the first-stage centrifugal separator 21 to ensure real-time monitoring of pressure at different locations. A variable frequency motor 33 is installed in the vacuum pump 5, and the pressure sensors 32 and the variable frequency motor 33 are connected to the PLC controller 31.

[0040] In actual operation, vacuum pump 5 is first started. Driven by variable frequency motor 33, vacuum pump 5 provides negative pressure to extraction unit 1. Gas phase extraction pipe 11 extracts volatile organic compounds (VOCs) from the soil, and liquid phase extraction pipe 12 extracts VOCs from the groundwater. The extracted gas and liquid phases pass through composite screen pipe 4. The 316L stainless steel sintered filter screen (10μm pore size) in composite screen pipe 4 filters out impurities from the soil and water. The hydrophobic activated carbon fiber felt 42 on both sides of screen 41 adsorbs VOCs, further improving the filtration effect. The material filtered by composite screen pipe 4 enters primary centrifuge 21. Primary centrifuge 21 uses centrifugal force to perform preliminary gas-liquid separation. The separated liquid phase is discharged from the bottom of primary centrifuge 21, and the gas phase enters secondary electrostatic coalescer 22 from the gas phase outlet of primary centrifuge 21. After startup, the variable frequency motor drives the vacuum pump to generate negative pressure, and pollutants enter the extraction pipe through the screen pipe. In the primary centrifugal separator, the gas-liquid mixture undergoes centrifugal force to achieve over 90% liquid phase separation. The remaining aerosols are then charged and adsorbed in the secondary electrostatic coalescer. The secondary electrostatic coalescer 22 further separates tiny liquid droplets from the gas phase through electrostatic coalescence, improving the purity of the gas phase. The remaining aerosols are charged and adsorbed in the secondary electrostatic coalescer, removing oil droplets with a particle size >1μm.

[0041] During processing, pressure sensor 32 monitors the pressure changes at the end of the gas phase extraction tube 11, the end of the liquid phase extraction tube 12, and the inlet and outlet of the first-stage centrifuge 21 in real time, and transmits the pressure data to PLC controller 31. PLC controller 31 controls the speed of variable frequency motor 33 based on the pressure data, thereby adjusting the negative pressure of vacuum pump 5 and achieving intelligent control. The PLC dynamically adjusts the extraction rate based on pressure sensor data, automatically reducing the motor speed when the detected pipeline pressure is >0.3MPa.

[0042] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A device for the treatment of soil and groundwater volatile organic compounds by multiphase extraction, comprising an extraction unit (1), a cyclonic unit (2) and an intelligent control unit (3), characterized in that: The extraction unit (1) comprises a gas-phase extraction pipe (11) and a liquid-phase extraction pipe (12), which are embedded in the contaminated soil layer in parallel, the outlet of the gas-phase extraction pipe (11) and the liquid-phase extraction pipe (12) is connected with a composite screen pipe (4), and the gas-phase extraction pipe (11) and the liquid-phase extraction pipe (12) are in sealed connection with the composite screen pipe (4), the cyclone unit (2) comprises a primary centrifugal separator (21) and a secondary electrostatic coalescer (22), the inlet end of the primary centrifugal separator (21) is connected with the composite screen pipe (4), the secondary electrostatic coalescer (22) is connected at the gas-phase outlet end of the primary centrifugal separator (21), the intelligent control unit (3) comprises a PLC controller (31), a pressure sensor (32) and a variable frequency motor (33), the pressure sensor (32) is arranged at the end of the gas-phase extraction pipe (11), the end of the liquid-phase extraction pipe (12) and the inlet and outlet of the primary centrifugal separator (21), and the extraction unit (1) further comprises a vacuum pump (5) for providing negative pressure, and the variable frequency motor (33) is installed in the vacuum pump (5).

2. The apparatus for soil and groundwater volatile organic compound multi-phase extraction treatment according to claim 1, characterized in that: The gas-phase extraction pipe (11) is made of a stainless steel corrugated pipe with a diameter of 50 mm.

3. The apparatus of claim 2, wherein: The liquid-phase extraction pipe (12) is made of a high-density polyethylene pipe with a diameter of 80 mm.

4. The apparatus of claim 3, wherein: A plurality of screen meshes (41) are installed in the composite screen pipe (4), the screen mesh (41) is made of a 316L stainless steel sintered filter screen, and the aperture of the screen mesh (41) is 10 μm.

5. A device for the treatment of soil and groundwater contaminated with volatile organic compounds by multiphase extraction according to claim 4, characterized in that: Hydrophobic activated carbon fiber felt (42) is arranged on both sides of the screen mesh (41), and the hydrophobic activated carbon fiber felt (42) is adhesively fixed with the screen mesh (41).

6. A device for the treatment of soil and groundwater contaminated with volatile organic compounds by multiphase extraction according to claim 5, characterized in that: The primary centrifugal separator (21) is made of a 316L stainless steel cyclone cylinder with a cone angle of 20°.

7. A device for the treatment of soil and groundwater volatile organic compounds by multiphase extraction according to claim 6, characterized in that: The secondary electrostatic coalescer (22) is made of a titanium alloy electrode group with an electrode spacing of 15 mm.

8. The apparatus of claim 7, wherein: The range of the pressure sensor (32) is 0-1 MPa, and the power of the variable frequency motor (33) is 5.5 kW.

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