CN112222173A

CN112222173A - Boiling type micro-foam multifunctional soil pollutant desorption device

Info

Publication number: CN112222173A
Application number: CN202010905101.9A
Authority: CN
Inventors: 李华; 朱宇恩; 张雅鑫; 吕宸琛
Original assignee: Shanxi University
Current assignee: Shanxi University
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2021-01-15
Anticipated expiration: 2040-09-01
Also published as: CN112222173B

Abstract

The utility model provides a boiling formula is multi-functional soil pollution thing desorption apparatus of foam a little, belongs to contaminated site soil remediation technical field, can solve the energy consumption that exists among the prior art high, the poor scheduling problem of effect, which comprises a housin, be equipped with the top cap on the casing, be equipped with strutting arrangement below the casing, be equipped with soil inlet on the casing side, be equipped with the ozone interface on the top cap, the liquid circulation interface, exhaust outlet, be equipped with little foam import in the lower part of casing, waste liquid discharge port and air current access mouth, be equipped with the ultrasonic vibrator outside the casing. The invention realizes the high-efficiency elution of the 'small amount' eluent. The surfactant is applied to ex-situ remediation of the organic contaminated soil in the form of micro-foam, so that a small amount of surfactant is fully contacted with pollutants, high dissolution rate of the pollutants is achieved, dissolution time is shortened, and cost is saved.

Description

Boiling type micro-foam multifunctional soil pollutant desorption device

Technical Field

The invention belongs to the technical field of contaminated site soil remediation, and particularly relates to a multifunctional boiling type micro-foam desorption device capable of realizing ozone-assisted ex-situ removal of soil pollutants.

Background

The removal of polycyclic aromatic hydrocarbons, benzene series, petroleum hydrocarbons and other volatile organic pollutants (VOCs) in the soil of the coking field is a current hotspot and difficulty, and the soil leaching method is widely applied to the remediation engineering of the VOCs polluted soil due to simple operation, low cost and good remediation effect. The method is also commonly used in combination with other treatment technologies, plays a role in enriching pollutants and reduces the amount of soil to be treated subsequently. Most of the existing eluting agents are surfactants, and most of the existing eluting agents are directly sprayed into the polluted soil for eluting, so that the defects of small contact area between the eluting agent and the pollutant, easy generation of pore channel effect to generate fixed channel flow, easy influence of soil permeability, large consumption of the eluting agent, high cost and unsatisfactory repairing effect are shown.

In order to overcome many defects existing in the traditional leaching repair, the traditional soil column leaching method is improved by some invention patents. For example, the invention patent with publication number CN 110877044 a discloses a leaching type soil remediation device, which is improved by the greatest improvement that the processes of soil crushing, screening and soil leaching are streamlined, and the friction washing is performed by using a stirring blade in the soil leaching process, but the device is complex to process, the leaching efficiency is low, and a large amount of leaching solution is consumed in the leaching process. For another example, the invention with publication number CN 109821871 a is named as an efficient soil leaching device, in which a rotary filter cartridge is arranged in a processing box, and a stirring device, a spraying device and a centrifugal filter device are arranged in the rotary filter cartridge, the stirring device can effectively improve the spraying effect, and the centrifugal filter device performs solid-liquid separation on the leached soil. Although the device provided by the invention can enhance the dissolving effect of pollutants to a certain extent, the requirement on the degree of mechanization is relatively high, the manufacturing cost of the device is high, and the phenomenon of insufficient leaching of the region which is not contacted with the stirring blade is easily caused due to the adoption of a mode of stirring to realize soil migration and increase the contact area.

Said invention still does not overcome the defect of large consumption of solution elution, and can convert the solution into microfoam, and can increase elution effective surface area, and the microfoam has the characteristics of large specific surface area, high mass transfer efficiency, long retention time and can produce lots of free radicals, etc.. In addition, because the foam flow rate can be controlled by the pressure gradient, the foam delivery can provide better control over the amount of fluid injected, thereby minimizing contaminant diffusion and leaching fluid waste. The micro-foam technology is widely applied to the field of water pollution remediation, and the application of the micro-foam technology in soil pollution treatment needs to be further explored.

However, the prior invention also applies the ultrasonic vibration device to soil washing and repairing, for example: the patent with application number 2013107194889 describes an apparatus and method for ultrasonic enhanced remediation of organic contaminated site soil. In the technical scheme, a high-speed stirring pulverizer, an ultrasonic generator and other devices are used, and under the action of ultrasonic waves and a pulverizing device, muddy water is used for eluting to achieve the purpose of removing pollutants. The patent with the application number of 2007101913182 discloses a method for repairing polycyclic aromatic hydrocarbon contaminated soil by ultrasonic waves, wherein the contaminated soil is irradiated by the ultrasonic waves with certain power and frequency, and pollutants such as polycyclic aromatic hydrocarbon in the soil can be reduced.

In the above document, ultrasonic waves are used as an auxiliary means to facilitate the removal of contaminants from soil by the dual action of ultrasonic waves in combination with mechanical pulverization. However, in the above scheme, the soil is directly crushed and eluted by a large amount of water, which wastes energy and may have a great influence on the physicochemical properties of the soil.

Disclosure of Invention

Aiming at the problems of high energy consumption, poor effect and the like in the prior art, the invention provides a boiling type micro-foam multifunctional soil pollutant desorption device.

The boiling type micro-foam multifunctional soil pollutant desorption device comprises a shell, a top cover is arranged on the shell, a supporting device is arranged below the shell, a soil inlet is arranged on the side surface of the shell, an ozone interface, a liquid circulation interface and a waste gas outlet are arranged on the top cover, a micro-foam inlet, a waste liquid outlet and an air flow inlet are arranged at the lower part of the shell, and an ultrasonic vibrator is arranged outside the shell.

The middle part of the shell is horizontally fixed with a micropore bearing plate, a through air hole and micropores are arranged in the micropore bearing plate, the through air hole is connected with an air flow access port through an air passage, an umbrella-shaped air flow circulation baffle is arranged above the through air hole, the through air hole and the micropores are uniformly distributed on the micropore bearing plate, and an air flow homogenization baffle is arranged above the inner part of the shell.

The use method of the device comprises the steps of putting the polluted soil into the shell through the soil inlet on the side surface, and then sealing the soil inlet. The ozone interface is connected with an ozone generator, the airflow access port is connected with an air pump, the foam generator is connected with the foam access port after the boiling treatment, and the desorption treatment of soil pollutants is carried out under the action of ultrasonic vibration.

The specific use method is that firstly, soil is sent into the shell from the soil inlet, and under the condition of small soil treatment amount, the soil can be sent into the desorption disc by a medicine spoon; when the soil treatment capacity is large, the stable and continuous conveying of the soil can be realized through the conveying structure; opening an ozone generator switch, controlling the flow of ozone at 0.3L/min, pre-oxidizing the polluted soil, and simultaneously taking away some volatile gases in the soil when ozone is discharged; then the air pump is opened, the air is connected through the interface below the device, the air flow enters the soil chamber through the umbrella-shaped air flow circulating baffle plate, and the soil is boiled through the baffle plate in the soil chamber and the adjustment of the air inflow. The flow velocity of the airflow inlet is 23.4-32.4 m/s; stopping inputting ozone and air flow after 2min, opening a peristaltic pump of a liquid-phase pipeline, simultaneously starting an air pump of the liquid-phase pipeline, pumping surfactant solution with certain concentration under the premise of controlling the gas-liquid ratio, generating micro-foam through a micro-foam generator, then entering a desorption device through a micro-foam interface, closing the peristaltic pump and the air pump after the whole container is filled with foam, stopping inputting the foam, rotating one end of a hose connected with the foam generator to a liquid circulation interface connected with a top cover, and realizing foam backflow through the air pump. The whole shell is placed in an ultrasonic vibration container, and the polluted soil pollutants are desorbed under the action of ultrasonic waves; and after 15min, closing the ultrasonic vibration, connecting one end of a hose connected with a part of liquid circulation interface of the top cover to a vacuum pump and a waste liquid collecting bottle, discharging the micro-foam surfactant solution containing the organic pollutants after the reaction, and defoaming and performing subsequent treatment on the pollutants. If soil blocks the micropores of the bearing plate in the process of extracting the waste liquid, the air pump can be started to perform back flushing from bottom to top. The waste gas discharged in the whole process enters a waste gas collecting bottle and is adsorbed by active carbon.

Compared with the prior art, the surfactant foam desorption device provided by the invention has the following outstanding advantages:

1. realizes the high-efficiency elution of the 'small amount' eluent. The surfactant is applied to ex-situ remediation of the organic contaminated soil in the form of micro-foam, so that a small amount of surfactant is fully contacted with pollutants, high dissolution rate of the pollutants is achieved, dissolution time is shortened, and cost is saved.

2. Realizes the elution of the soil desorption device without dead angles. Micro-foam homogenization is realized through the porous structure, the foam is distributed uniformly and is distributed over the whole desorption device, and the soil is fully immersed without dead angles. Ultrasonic vibration realizes the high-frequency vibration state of the desorption process, strengthens the friction between particles, improves the contact probability of the eluent and pollutants, and realizes the rapidity of elution and degradation without dead angles of soil adsorption pollutants.

3. Realizes the 'boiling' operation of the desorption process of the device. The boiling occurrence state of the soil with different textures under lower energy consumption can be realized through the preset gas critical flow velocity of the boiling of the soil with different textures, and the targeted oxidation and elution of volatile organic pollutants and pollutants adsorbed in soil media can be realized through different boiling states at different stages, so that the pollutants are removed.

4. The multifunctional device realizes the 'multipurpose' function of a set of devices. The device is widely applied, can be used for the elution effect of multiple pollutants, can realize the elution to polycyclic aromatic hydrocarbon, benzene series thing through changing surfactant active, is assisted with ozone function and nutrient solution, microbial inoculum and adds the function, can realize the activation degradation to pollutants such as antibiotic in the soil.

In summary, the device of the present invention can use surfactant solution to transform into active agent with nano-attribute micro-foam to increase its specific surface area, reduce the amount of leacheate used, and make soil "fluidized" by air flow impact, which is beneficial to fully contact the surfactant micro-foam with pollutants. The device can utilize the foam to carry out 'boiling type' impregnation without dead angles on the polluted soil under the action of ultrasonic vibration, and the foam plug flow type rises so as to avoid the phenomenon similar to a fixed liquid phase flow channel generated in the traditional soil column leaching. In addition, the staged treatment of soil organic pollutants can be realized during the operation of the device. Can be applied to the dissolution of polycyclic aromatic hydrocarbon and other organic pollutants in a coking field, the ozone oxidation and the removal of other organic pollutants such as soil antibiotics. The contact frequency between the foam and the contaminated soil is increased by ultrasonic vibration. The ultrasonic vibration collects the surfactant microemulsion containing polycyclic aromatic hydrocarbon in soil micropores by utilizing the principle of capillary action, the surfactant microfoam emulsion is vibrated and decomposed by utilizing ultrasonic waves to form smaller liquid drops so as to be convenient to move, and soil boiling is realized by ultrasonic vibration and airflow impact to efficiently elute pollutants.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic view of the internal structure of the present invention;

FIG. 3 is a schematic top view of the top cover of the present invention;

FIG. 4 is a schematic structural view of an umbrella-shaped airflow circulation baffle of the present invention;

FIG. 5 is a schematic view of the structure of a soil input port of the present invention;

FIG. 6 is an ANSYS software simulated airflow movement;

wherein: 1-a shell; 2-a soil inlet; 3-an upper baffle plate; 4-umbrella-shaped airflow circulating baffle plates; 5-a microporous bearing plate; 6-inlet of micro-foam; 7-a waste liquid discharge port; 8-an airflow access port; 9-a support device; 10-a top cover; 11-ozone interface; 12-a liquid circulation interface; 13-exhaust gas outlet; 14-a lower baffle; 15-through air holes; 16-micropores; 17-the airway; 18-an ultrasonic generator; 19-cover.

Detailed Description

The invention is further explained with reference to the accompanying drawings.

As shown in fig. 1 and 2, the boiling type micro-foam multifunctional soil pollutant desorption device comprises a shell 1, a top cover 10 is arranged on the shell 1, a supporting device 9 is arranged below the shell 1, a soil inlet 2 is arranged on the side surface of the shell 1, an ozone interface 11, a liquid circulation interface 12 and a waste gas outlet 13 are arranged on the top cover 10, a micro-foam inlet 6, a waste liquid outlet 7 and an air flow inlet 8 are arranged on the lower portion of the shell 1, and an ultrasonic generator 18 is arranged outside the shell 1.

The middle part of the shell 1 is horizontally fixed with a micropore bearing plate 5, a through air hole 15 and a micropore 16 are arranged in the micropore bearing plate 5, the through air hole 15 is connected with an air flow access port 8 through an air passage 17, an umbrella-shaped air flow circulation baffle 4 is arranged above the through air hole 15, the through air hole 15 and the micropore 16 are uniformly distributed on the micropore bearing plate 5, and an air flow homogenizing baffle is arranged inside the shell 1.

And a bracket is arranged above the through air hole 15 on the micropore bearing plate 5 and is used for fixing the umbrella-shaped airflow circulating baffle 4.

As illustrated in fig. 2, the flow homogenizing baffle comprises an upper baffle 3 and a lower baffle 14.

The upper portion of the upper baffle 3 is connected with the top cover 10, the upper baffle 3 is two and arranged in a splayed mode, the space on the upper portion of the shell 1 is divided into three parts by the two upper baffles 3, the ozone interface 11 is located in the space on one side, the waste gas outlet 13 is located in the space on the other side, the liquid circulation interface 12 is located in the space in the middle, and the lower baffle 14 is arranged in an upward inclined mode and located in the space below the waste gas outlet 13.

The microporous bearing plate 5 is provided with a nylon net, and the aperture of the nylon net is 60-450 meshes.

The shell 1 is made of acrylic materials, the liquid circulation interface 12 is arranged at the center of the top cover, the outer wall of the interface is of a threaded structure and is provided with a cover, and the cover can be screwed down when foam circulation is not performed; in the soil pollutant desorption process, the soil pollutant desorption device is connected with the micro-foam inlet 6 by a hose, and the circulation of eluting foam is realized by an air pump. Two 1/4 diameter positions on the same diameter at the two ends of the circle center of the top cover are provided with two small holes, one is connected with an ozone generator for introducing ozone, and the other is connected with an activated carbon adsorption column for discharging waste gas. The top cover can be fixed on the desorption device through bolts.

The housing 1 has a diameter: high = 5: 4, a soil inlet 2 with the diameter of 1/4 cylinder height is arranged on the side surface of the cylinder, and under the condition of small soil treatment capacity, soil can be sent to the inside of the desorption disc by a medicine spoon; when the soil handling capacity is large, the stable and continuous conveying of the soil can be realized through the conveying structure.

As illustrated in fig. 5, a threaded section is provided outside the soil inlet 2, on which a cap 19 is provided. In the beginning of the desorption operation, the cap 19 needs to be tightened to prevent leakage.

As shown in FIG. 4, the diameter of the through-air holes 15 is 1mm, and the diameter of the micro-holes 16 is 0.1 mm. The air flow with certain pressure enters from the air flow inlet 8 and is connected to the through air holes 15 below the umbrella-shaped air flow circulating baffle 4 through the pipeline 17, so that the flow equalization of the air flow in the device is realized.

The micropore bearing plate 5 is of an inverted cone structure, three connectors, a micro-foam inlet 6, a waste liquid outlet 7 and an airflow inlet 8 are arranged at the lower end of the inverted cone device.

The micro-porous bearing plate 5 is used as a boundary, the upper half part of the device is mainly used for placing polluted soil, the air flow and the ultrasonic vibration can realize the boiling type mixing of the soil and the foam, the full contact is ensured, the friction between the soil and the foam and between the soil and the wall of the container is enhanced, and the rapid removal of pollutants is facilitated. The lower half part of the device is mainly used for enabling air flow and foam to uniformly enter a desorption container and collecting liquid after reaction. The pressure difference generated by the compressed air pump enables the solution after the foam is broken to flow into the bottom through the small holes on the supporting plate for temporary storage.

The utility model provides a boiling formula microfoam multifunctional soil pollutant desorption device which equipment and pollutant desorption process as follows:

(1) assembly of microfoam desorption device route

Connecting pipelines: connect waste gas discharge port 13 to the active carbon adsorption post through the hose, ozone pipeline connects ozone interface 11, and little foam import 6 is connected to the foam generator, and waste liquid collecting bottle is connected to waste liquid discharge port 7, and the air pump passes through the air current pipeline and connects bottom air current access mouth 8, and the air current access mouth 8 upper end connects to penetrating air hole 15 after shunting through air flue 17.

Secondly, fixing a nylon net in the shell, covering a top cover and screwing screws, wherein the diameter of the nylon net is the same as that of the micropore supporting plate 5 of the shell.

(2) Micro-foam desorption process

Firstly, soil is sent into a device in a shell from a soil inlet 2, and when the soil treatment capacity is not large, the soil can be sent into a desorption disc by a medicine spoon; when the soil treatment capacity is large, the stable and continuous conveying of the soil can be realized through the conveying belt;

secondly, turning on a switch of the ozone generator, controlling the flow of ozone to be 0.3L/min, pre-oxidizing the polluted soil, and simultaneously taking away some volatile gases in the soil when ozone is discharged;

thirdly, the air pump is turned on, air is connected through an air flow inlet 8 below the device, the air flow enters the upper part of the shell 1 through an air passage 17 after changing the flow direction through the umbrella-shaped air flow circulating baffle 4, and then the soil is boiled through three baffles and the adjustment of air inflow;

fourthly, after 2min, the ozone generator and the air pump are closed, the peristaltic pump of the liquid phase pipeline connected with the foam generator is opened, the air pump is started, surfactant solution with certain concentration is pumped in on the premise of controlling the gas-liquid ratio, the micro foam generated by the micro foam generator is injected through the interface 6, and the peristaltic pump and the air pump are closed after the whole container is filled with the foam; the liquid circulation port 12 and the foam generating device are connected by a hose, and foam backflow is realized by a circulation pump. The whole desorption device is arranged in an ultrasonic vibration container to desorb the pollutants in the polluted soil;

after 15min, turning off the ultrasonic vibration, pumping out the reacted micro-foam surfactant by using a vacuum pump, collecting the micro-foam surfactant by using a liquid collecting bottle, and defoaming and performing subsequent treatment on pollutants. If soil blocks the micropores of the bearing plate in the process of extracting the waste liquid, the air pump can be started to perform back flushing from bottom to top. The waste gas discharged in the reaction process enters a waste gas collecting bottle and is adsorbed by active carbon.

The specific embodiment mainly researches the stability of the homogenized microfoam, the movement condition of the soil with different textures under the drive of the airflow of the device (combining ANSYS software) and the effect of using the device for eluting pollutants.

Example 1 (stability after foam homogenization): 20mmol/L of Tween 80 surfactant is prepared to be used as a foaming agent, and the foaming agent is prepared by mixing the following components in a gas-liquid ratio of 30: 1, utilizing a micro-foam generating device to generate micro-foam, referring to the attached figure 1, fixing nylon gauze with different pore diameters at the bottom of a desorption container respectively, and verifying the influence of homogenizing structures with different pore diameters on the foam in the device. The results are shown in Table 1 below.

Table 1:

example 2 (fluidization process simulation):

and adding the same amount of soil with different textures into a detaching device, blowing air flow from the interface 8 by using an air pump, adjusting the size of the air flow to realize the boiling of the soil, verifying the blocking effect of the soil with different textures on the air flow so as to select a proper air flow rate according to the texture of the soil to take out the volatile organic compounds, and simulating the air flow rate of an air outlet according to ANSYS software. The results are shown in Table 2, and it is found from example 2 that the minimum air flow rate required to achieve "boiling" of the soil is 23.4m/s, and the fluidization effect of the sand is most easily achieved.

Table 2:

example 3 (verification of volatile organic compound removal effect):

preparing polluted soil: gather uncontaminated sand soil, loam, clay, air-dry, grind and cross 2mm sieve, with soil and acetone with 25: 1, sufficiently stirring in a relatively sealed environment to ensure uniform mixing, and then placing the prepared acetone-containing soil in a soil chamber of the device shown in figure 1.

Soil "boiling": and (3) starting an airflow conveying pipeline, allowing the volatile organic matters to enter the activated carbon adsorption device through the gas discharge port under the movement of airflow, and simultaneously starting the ozone generator, wherein the boiling process lasts for about 2 min.

Preparing the micro-foam: preparing 20mmol/L Tween 80 solution, placing the solution in a beaker, and after the device is assembled, mixing Tween 80 and air according to the gas-liquid ratio of 30: 1, introducing into a micro-foam generator, introducing the formed micro-foam into a desorption device from the bottom, contacting with the soil containing acetone through a nylon gauze with a pore size of 100 meshes, stopping introducing the foam after the whole elution container is filled with the foam (about 2 min), and vibrating the desorption device in an ultrasonic vibration device for 15 min. The influence of the soil with different textures and the fluidization treatment on the removal rate of the volatile organic compounds (acetone) is verified respectively.

And (3) acetone determination: the amount of volatile organic compounds in the apparatus was measured with a MiniRAE 3000 hand-held VOC detector when the acetone-containing soil was placed in the desorption vessel and after the desorption process was completed. The measurement results are shown in Table 3.

Table 3:

Claims

1. the utility model provides a multi-functional soil contaminant desorption device of boiling formula microfoam, includes casing (1), is equipped with top cap (10) on casing (1), is equipped with strutting arrangement (9), its characterized in that below casing (1): the device is characterized in that a soil inlet (2) is arranged on the side surface of the shell (1), an ozone interface (11), a liquid circulation interface (12) and a waste gas outlet (13) are arranged on the top cover (10), a micro-foam inlet (6), a waste liquid outlet (7) and an air flow inlet (8) are arranged at the lower part of the shell (1), and an ultrasonic generator (18) is arranged outside the shell (1).

2. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: the novel air flow homogenizing device is characterized in that a micropore bearing plate (5) is horizontally fixed in the middle of the shell (1), a through air hole (15) and a micropore (16) are arranged in the micropore bearing plate (5), the through air hole (15) is connected with an air flow access port (8) through an air passage (17), an umbrella-shaped air flow circulating baffle (4) is arranged above the through air hole (15), the through air hole (15) and the micropore (16) are uniformly distributed on the micropore bearing plate (5), and an air flow homogenizing baffle is arranged inside the shell (1).

3. The boiling type microfoam multifunctional soil pollutant desorption device as recited in claim 2, wherein: the flow homogenizing baffle comprises an upper baffle (3) and a lower baffle (14).

4. The boiling type microfoam multifunctional soil pollutant desorption device of claim 3, wherein: the upper baffle (3) top be connected with top cap (10), overhead gage (3) are two, are the splayed setting, two overhead gage (3) divide into the triplex with casing (1) upper portion space, ozone interface (11) are located one side space, exhaust outlet (13) are located the opposite side space, liquid circulation interface (12) are located the middle part space, lower baffle (14) tilt up setting, and be located the space of exhaust outlet (13) below.

5. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: the microporous bearing plate (5) is provided with a nylon net, and the aperture of the nylon net is 60-450 meshes.

6. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: the shell (1) has a diameter: high = 5: 4, the side surface of the cylinder is provided with a soil inlet (2) with the diameter of the cylinder height 1/4.

7. The boiling type microfoam multifunctional soil contaminant desorption device as recited in claim 1 or 6, wherein: a thread section is arranged outside the soil inlet (2), and a cover (19) is arranged on the thread section.

8. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: the aperture of the through air hole (15) is 1mm, and the aperture of the micropore (16) is 0.1 mm.

9. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: the microporous bearing plate (5) is of an inverted cone structure, three connectors, a microfoam inlet (6), a waste liquid outlet (7) and an air flow inlet (8) are arranged at the lower end of the inverted cone device.

10. The boiling type microfoam multifunctional soil pollutant desorption device of claim 1, wherein: and a bracket is arranged above the through air hole (15) on the micropore bearing plate (5), and the umbrella-shaped airflow circulating baffle (4) is fixed by the bracket.