A filtering and bubbling dust removal device and method

Abstract

The present invention discloses a novel filtering and bubbling dust removal device and method. The device includes a container. A gas outlet is provided at the top of the container, and a dust-containing gas inlet passage is provided at the bottom of the container. A coarse filtering surface is provided in the upper part of the container inside the dust-containing gas inlet passage. A dust removal liquid is provided above the coarse filtering surface. It further includes a super-hydrophilic micro filter screen located above the coarse filtering surface. The super-hydrophilic micro filter screen is immersed in the dust removal liquid. A first liquid drainage passage is provided on the side wall of the container between the super-hydrophilic micro filter screen and the coarse filtering surface. A liquid inlet passage is provided on the side wall of the container above the super-hydrophilic micro filter screen. A second liquid drainage passage is opened at the top of the container. Valves are respectively provided on the first liquid drainage passage, the second liquid drainage passage and the liquid inlet passage. The novel filtering and bubbling dust removal device and method of the present invention can effectively remove hydrophobic particles in the gas, and has the advantages of not being easily blocked, simple to clean and sufficient filtering.

Description

Technical Field

[0001] The present invention relates to the field of air purification, and particularly to a filtering bubbling dust removal device and method. Background Art

[0002] Productive dust mainly comes from the mechanical crushing and grinding of solid materials, the mixing, screening, packaging and transportation of powdery materials, the soot generated by the combustion of substances, and the oxidation and condensation of vapors generated when substances are heated in the air. Due to the rapid development of modern industry, the types of new dust and the generation amount of respirable dust have increased significantly. Dust can cause pneumoconiosis and trigger explosions, posing serious hazards to human health and life safety.

[0003] The respirable dust has an extremely small particle size and cannot be directly observed by the naked eye. The deposition behavior of these tiny particles is closely related to their aerodynamic diameter. Particles with a diameter less than 5μm may penetrate deep into the lower respiratory tract of the human body, and even penetrate the defense mechanism of the respiratory system and reach the lungs. Workers in a high-concentration dust environment for a long time will significantly increase the probability of suffering from pneumoconiosis.

[0004] On the other hand, when the concentration of combustible dust accumulates to a certain extent, it will cause a dust explosion when encountering a fire source, resulting in heavy casualties and property losses. The shock wave generated after the dust explosion will raise the deposited dust, leading to continuous explosions.

[0005] Therefore, doing dust prevention and control work and improving the efficiency of dust prevention and control is still an important task.

[0006] At present, dust collectors in the field of industrial dust prevention and control are mainly divided into two types: dry and wet dust removal methods. Dry dust removal is represented by electrostatic and filtration dust removal, etc. Among them, electrostatic dust removal is a device that uses a strong electric field to ionize gas to charge dust and separates the dust by using the electric field force. Electrostatic dust removal can better settle micron dust, but the device operation and maintenance are complex; filtration dust removal uses a dense filter element as the dust removal medium, and short-term and high-efficiency dust removal can be achieved by adjusting the accuracy of the filter element, etc.

[0007] Wet dust removal is mainly represented by spray and foam tower dust removal. Among them, spray dust removal means that the dusty gas is the continuous phase, and the washing liquid is in the form of dispersed phases such as droplets to wash the dusty gas. However, due to the difficulty of effective contact between the washing liquid and small particle dust, the sedimentation rate of respirable dust is relatively low; foam tower dust removal takes the liquid as the continuous phase and the gas as the dispersed phase. The gas flow enters the liquid through the sieve plate and forms a boiling foam layer on the sieve plate, and most of the dust particles are washed.

[0008] In addition, the representative improvement based on bubbling dust removal is the gas-dispersed microbubble method. It means that the dust-laden air is fully broken into microbubbles and dispersed into the purification solution after passing through the granular bed, and then the purification solution adsorbs or chemically reacts with the dust to fully purify the air contaminated with dust. This method can reduce the blockage of dust particles at the filtration interface, but it cannot effectively remove hydrophobic particles in the gas.

[0009] It can be seen that there are still problems in filtration dust removal, such as the easy blockage of the filter mesh holes, the difficult maintenance of the filter mesh due to the high humidity of the dust-containing gas, and the insufficient continuous high-efficiency operation time; the foam tower dust removal is affected by too many external factors, and it is not easy to capture and remove dust. Therefore, it is very necessary to develop a method and technology that is simple to process, has a simple structural device, does not produce secondary pollution, the filter device does not get blocked, and can fully capture dust particles. Summary of the Invention

[0010] In view of the above technical problems, the present invention proposes a filtering bubbling dust removal device and method. A multi-stage filtering method combining a coarse filtering surface and a super-hydrophilic micro-filter screen is adopted to gradually filter the dust-containing gas to improve the dust removal effect. Among them, the coarse filtering surface first preliminarily filters the dust-containing gas to remove larger particulate matters, thereby reducing the filtering burden on the super-hydrophilic micro-filter screen. The super-hydrophilic micro-filter screen has excellent hydrophilic properties, and a surfactant with strong hydrophilicity is added to the dust removal liquid to enhance the ability to capture and adsorb dust. Immersing it in the dust removal liquid can further improve the filtering effect on dust. In addition, by setting up a liquid inlet channel, a first liquid discharge channel and a second liquid discharge channel, and installing valves on these channels, a circulation and renewal system for the dust removal liquid is constructed, which can maintain the cleanliness and effectiveness of the dust removal liquid and improve the dust removal efficiency. The present invention can solve the problems that the existing bubbling dust treatment device cannot effectively remove hydrophobic particles in the gas, the filter screen is easy to be blocked, difficult to clean, consumes a lot of materials, and the filtration is insufficient.

[0011] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0012] A filtering bubbling dust removal device includes a container. A gas outlet is provided at the top of the container, and a dust-containing gas inlet channel is provided at the bottom of the container. Inside the container, above the dust-containing gas inlet channel, there is a coarse filtering surface for preliminarily filtering the dust-containing gas. Inside the container, above the coarse filtering surface, there is a dust removal liquid. It also includes a super-hydrophilic micro-filter screen, which is located above the coarse filtering surface and immersed in the dust removal liquid. A first liquid discharge channel is provided on the side wall of the container between the super-hydrophilic micro-filter screen and the coarse filtering surface;

[0013] A liquid inlet channel is provided on the side wall of the container above the super-hydrophilic micro-filter screen, and the liquid inlet channel is used to introduce the dust removal liquid into the container;

[0014] A second liquid discharge channel is provided at the top of the container;

[0015] A first valve is provided on the first liquid discharge channel, a second valve is provided on the second liquid discharge channel, and a third valve is provided on the liquid inlet channel.

[0016] The air inlet mesh holes of the coarse filtration surface have a diameter of 7-9 mm.

[0017] The mesh holes of the super-hydrophilic micro filter screen have a diameter of 10-30 μm.

[0018] The coarse filtration surface and the super-hydrophilic micro filter screen are made of stainless steel mesh.

[0019] The first valve on the first liquid discharge channel is a gate valve; the second valve on the second liquid discharge channel and the third valve on the liquid inlet channel are both check valves to prevent liquid backflow.

[0020] The present invention further discloses a dust removal method based on the filter bubbling dust removal device, including the following steps:

[0021] S1. Adding dust removal liquid

[0022] Keep the first valve on the first liquid discharge channel and the second valve on the second liquid discharge channel closed, and open the third valve on the liquid inlet channel. The dust removal liquid flows into the container through the liquid inlet channel at a certain flow rate. When the content of filtered dust in the container solution is too high, open the first valve and the second valve, and let it flow out through the first liquid discharge channel and the second liquid discharge channel;

[0023] S2. Filtering dust-containing gas

[0024] Keep the first valve on the first liquid discharge channel, the second valve on the second liquid discharge channel, and the third valve on the liquid inlet channel closed, and ensure that the dust-containing gas is purified through two layers of filter meshes; the dust-containing gas enters the bottom of the container from the dust-containing gas inlet channel, first passes through the coarse filtration surface, filters out larger particles in the dust-containing gas, and also reduces the accumulation of particles in the subsequent filtration process;

[0025] After that, the dust-containing gas enters the dust removal liquid, forms large bubbles in the dust removal liquid, and rises with the flow of the dust removal liquid into the super-hydrophilic micro filter screen. At this time, the large bubbles are divided into several small bubbles; fine dust particles are captured by the liquid through the super-hydrophilic surface of the super-hydrophilic micro filter screen. The dust particles continue to move due to inertia, and finally contact the gas-liquid interface and are dragged into the dust removal liquid; finally, the filtered dust-containing gas is discharged from the gas outlet at the top of the container.

[0026] When the content of filtered dust in the container solution exceeds the set value, open the first valve on the first liquid discharge channel, the second valve on the second liquid discharge channel, and the third valve on the liquid inlet channel to update the dust removal liquid in the container.

[0027] The selection of the surfactant is obtained according to the dust wetting experiment.

[0028] Technical effects:

[0029] 1. The present invention uses a coarse filter surface to initially filter some large particles, and then uses a super-hydrophilic microfiltration membrane and a filtering solution to purify the dust-containing gas entering the system. The super-hydrophilic microfiltration membrane can significantly improve the adsorption and capture ability of dust particles through its special wetting performance. At the same time, a relatively hydrophilic surfactant is added to the dust removal liquid, which can enhance the affinity between the super-hydrophilic surface and the liquid, and the super-hydrophilic surface can be completely wrapped by the liquid. When hydrophilic / hydrophobic dust particles pass through the mesh surface, they will be better captured by the liquid, thus achieving efficient filtration.

[0030] If a relatively hydrophilic surfactant is not added to the dust removal liquid in the filtering container, the super-hydrophilic microfiltration membrane will also face the problems that occur during long-term dust filtration of the filtering device. The pores of the super-hydrophilic microfiltration membrane are in the micron range. During the dust removal process, dust particles are easily attached to the microfiltration membrane, resulting in filter clogging. Although the super-hydrophilic microfiltration membrane has hydrophilic properties, if the adhesion of dust is strong or the particle size of the particulate matter is small, clogging may still occur, affecting the dust removal effect and the stability of the system. To maintain the performance of the filter, it needs to be cleaned and maintained regularly. However, the special structure of the super-hydrophilic microfiltration membrane may make the cleaning process complicated, and appropriate cleaning methods and tools are required to ensure that the filter can be thoroughly cleaned and its performance can be restored.

[0031] The present invention solves the problems in the previous filtration technologies, such as the replacement and cleaning of the filtering device, easy clogging; insufficient contact between dust and the dust removal liquid, difficult to be captured; and pollution of the filtration product.

[0032] 2. The present invention can be applied to various dust-generating places such as industrial enterprises and construction sites. The surfactant with strong wettability in the dust removal liquid can reduce the surface tension of the interface, and the super-hydrophilic surface wrapped by this liquid can better prevent dust particles from accumulating on its surface area.

[0033] The super-hydrophilic microfiltration membrane can significantly improve the adsorption and capture ability of dust particles through its special wetting performance. At the same time, a relatively hydrophilic surfactant is added to the filtering liquid, which can enhance the affinity between the super-hydrophilic microfiltration membrane and the liquid, and the super-hydrophilic microfiltration membrane is completely wrapped by the liquid. When hydrophilic / hydrophobic dust particles pass through the mesh surface, they will be better captured by the liquid, thus achieving efficient filtration.

[0034] 3. The present invention uses stainless steel to manufacture the coarse filtration surface and the super-hydrophilic micro filter screen, which has excellent corrosion resistance and abrasion resistance, and can operate stably for a long time under harsh working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of the present invention;

[0036] In the figure: 1 - the first liquid discharge channel, 2 - the super-hydrophilic micro filter screen, 3 - the second liquid discharge channel, 4 - the coarse filtration surface, 5 - the gas outlet, 6 - the liquid inlet channel, 7 - the dust-containing gas inlet channel;

[0037] Figure 2 is the force analysis acting on the particles at the bubble interface;

[0038] In the figure: F B — buoyancy, F G — the gravity of the particle itself, F P — the pressure of the bubble on the particle, F γ — the surface tension of the liquid, θ — contact angle. DETAILED DESCRIPTION OF THE INVENTION

[0039] Next, the technical solutions in the present invention will be clearly and completely described according to the schematic structural diagram in the present invention.

[0040] As Figure 1 shown, a filtering bubbling dust removal device of the present invention includes a container. A gas outlet 5 is provided at the top of the container, and a dust-containing gas inlet channel 7 is provided at the bottom of the container. A coarse filtration surface 4 for preliminarily filtering the dust-containing gas is provided above the dust-containing gas inlet channel 7 inside the container. Dust removal liquid is provided above the coarse filtration surface 4 inside the container. The device further includes a super-hydrophilic micro filter screen 2, which is located above the coarse filtration surface 4 and immersed in the dust removal liquid. A first liquid discharge channel 1 is provided on the side wall of the container between the super-hydrophilic micro filter screen 2 and the coarse filtration surface 4;

[0041] A liquid inlet channel 6 is provided on the side wall of the container above the super-hydrophilic micro filter screen 2, and the liquid inlet channel 6 is used to introduce dust removal liquid into the container;

[0042] A second liquid discharge channel 3 is opened at the top of the container;

[0043] A first valve is provided on the first liquid discharge channel 1, a second valve is provided on the second liquid discharge channel 3, and a third valve is provided on the liquid inlet channel 6.

[0044] As a preferred technical means of the present invention, the diameter of the air inlet mesh holes of the coarse filtration surface is 7-9 mm. The dust-containing gas is not likely to accumulate on the coarse filtration surface.

[0045] As a preference of the technical means of the present invention, the pore diameter of the super-hydrophilic micro filter screen is 10-30 μm. A surfactant with strong wettability is added to the dust removal liquid. The super-hydrophilic micro filter screen is completely wrapped by the dust removal liquid, and there is a strong adsorption effect between the two, which can also prevent the accumulation of dust.

[0046] As a preference of the technical means of the present invention, the coarse filtration surface and the super-hydrophilic micro filter screen are made of stainless steel mesh. The super-hydrophilic micro filter screen is prepared by electrodeposition.

[0047] As a preference of the technical means of the present invention, the first valve on the first liquid discharge channel adopts a gate valve; the second valve on the second liquid discharge channel and the third valve on the liquid inlet channel both adopt check valves to prevent the liquid from flowing back.

[0048] The present invention further discloses a dust removal method based on the above-mentioned filter bubble dust removal device, including the following steps:

[0049] When the system performs the filtering work,

[0050] S1. Add the dust removal liquid

[0051] Keep the first valve on the first liquid discharge channel and the second valve on the second liquid discharge channel closed, and open the third valve on the liquid inlet channel. The dust removal liquid flows into the container at a certain flow rate through the liquid inlet channel. When the content of the filtered dust in the container solution is too high, open the first valve and the second valve, and let them flow out through the first liquid discharge channel and the second liquid discharge channel;

[0052] S2. Filter the dust-containing gas

[0053] Keep the first valve on the first liquid discharge channel, the second valve on the second liquid discharge channel, and the third valve on the liquid inlet channel closed, and ensure that the dust-containing gas is purified by the two-layer filter screen; the dust-containing gas enters the bottom of the container from the dust-containing gas inlet channel, first passes through the coarse filtration surface, filters the larger particles in the dust-containing gas, and at the same time reduces the accumulation of particles in the subsequent filtration process;

[0054] After that, the dust-containing gas enters the dust removal liquid, forms large bubbles in the dust removal liquid, and rises with the flow of the dust removal liquid into the super-hydrophilic micro filter screen. At this time, the large bubbles are divided into several small bubbles; the fine dust particles are captured by the liquid through the super-hydrophilic surface on the super-hydrophilic micro filter screen. The dust particles continue to move due to inertia, and finally contact the gas-liquid interface and are dragged into the dust removal liquid. Finally, the filtered dust-containing gas is discharged from the gas outlet at the top of the container;

[0055] As Figure 2 shown, it is the force analysis acting on the particles at the bubble interface. In the figure: F B —Buoyancy, F G—Gravity of the particle itself, F P —Pressure of the bubble on the particle, F γ —Surface tension of the liquid, θ—Contact angle.

[0056] The velocity of the particle moving to the gas-liquid interface is 0. The resultant force on the particle includes the gravity of the particle itself, the pressure F of the bubble on the particle P , the surface tension F of the liquid γ and buoyancy. Ignoring the gravity and buoyancy of the particle because they are negligible compared to the surface tension, then the resultant force F = F P -F γ . When the contact angle θ is greater than 90°, most of the volume of the particle is on the gas side; when the contact angle θ is less than 90°, the particle tends to enter the liquid. The resultant force on the particle determines its moving direction, and this force depends on the wettability of the particle. Adding a surfactant with strong hydrophilicity to the filtrate reduces the liquid surface tension, and hydrophobic particles can also enter the liquid.

[0057] Furthermore, when the content of dust particles in the container solution exceeds the set value, open the first valve on the first liquid discharge channel, the second valve on the second liquid discharge channel, and the third valve on the liquid inlet channel to update the dust removal liquid in the container.

[0058] In the present invention, the selection of the surfactant is obtained according to the dust wetting experiment.

[0059] The device of the present invention is simply designed, convenient for operation and maintenance, can solve the problems of easy blockage of the filter screen, high energy consumption, and insufficient dust filtration existing in the existing dust and waste gas treatment technologies, and is applicable to various places with productive dust and waste gas treatment such as industry, enterprises, and engineering construction, and has great application value.

[0060] The selection of the surfactant added to the dust removal liquid can be obtained according to the dust wetting experiment, and examples are given below. Example

[0061] Weigh the surfactant to be tested and prepare a surfactant solution with a mass fraction of 0.2 wt.%. Use the sedimentation method to test the sedimentation time of the surfactant solution, and take the average value of three measurements as the final measurement result each time. The surfactant solutions are all prepared with deionized pure water, and the laboratory temperature is always maintained at 25±1°C. The measured sedimentation time results are as follows.

[0062] When the surfactant concentration is 0.2 wt.%, the wetting times are sorted in descending order as GT-248 < APG1214 < SDS < SDBS < APG0810 < CAB-35 < 1227. The wetting time of the GT-248 solution is the shortest at 59 s, and the wetting time of the 1227 solution is the longest at 1 h 35 m 18 s.

[0063] The hydrophobic group of GT-248 is fully methylated Si-O-Si, and the siloxane chain has good flexibility, allowing for a high-density packing of methyl groups (CH3-) on the surface. This results in a very low surface tension of the GT-248 surfactant solution and high surface activity, so the sedimentation time of the solution for coal dust is very small, and its wetting performance is the best among the surfactants used in the experiment. The worst wetting performance is shown by the cationic 1227 surfactant solution. In the molecular structure of the 1227 surfactant, both the benzene ring and the hydrocarbon chain are hydrophobic groups, and the only hydrophilic group is the middle amino group. When the surfactant molecules encounter coal powder, the strong hydrophobic interaction causes the hydrophobic ends of the surfactant molecules to face the coal dust, while the hydrophilic interaction is not strong enough to "pull" the coal powder into the solution. Therefore, the sedimentation time of the 1227 surfactant is longer, and its wetting effect on coal powder is not obvious. Surfactants with strong hydrophilicity can significantly improve the wettability of the coal dust surface.

Claims

1. A filtering bubbling dust removal device, comprising a container, a gas outlet is provided at the top of the container, a dust-containing gas inlet channel is provided at the bottom of the container, a coarse filtering surface for preliminary filtering of the dust-containing gas is provided in the upper part of the dust-containing gas inlet channel inside the container, and a dust removal liquid is provided in the upper part of the coarse filtering surface inside the container, characterized in that: It also includes a super-hydrophilic micro-filter, which is located on the upper part of the coarse filtration surface and immersed in the dust removal liquid, and a first liquid discharge channel is provided on the side wall of the container between the super-hydrophilic micro-filter and the coarse filtration surface; A liquid inlet channel is provided on the side wall of the container located above the super-hydrophilic micro-filter, and the liquid inlet channel is used to introduce dust removal liquid into the container; A second liquid discharge channel is provided on the top of the container; The first liquid discharge channel is provided with a first valve, the second liquid discharge channel is provided with a second valve, and the liquid inlet channel is provided with a third valve; The diameter of the air inlet mesh of the coarse filtration surface is 7-9 mm; The mesh diameter of the super-hydrophilic micro-filtration screen is 10-30 μm; A hydrophilic surfactant is added to the dust removal liquid.

2. The filtering bubbling dust removal device according to claim 1, characterized in that: The coarse filtration surface and the super-hydrophilic microfiltration mesh are stainless steel meshes.

3. The filtering bubbling dust removal device according to claim 1, characterized in that: The first valve on the first liquid discharge channel is a gate valve; the second valve on the second liquid discharge channel and the third valve on the liquid inlet channel are both check valves to prevent liquid from flowing back.

4. A dust removal method based on the filtering bubbling dust removal device according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Add dust removal fluid Keep the first valve on the first liquid discharge channel and the second valve on the second liquid discharge channel closed, and the third valve on the liquid inlet channel open, so that the dust removal liquid flows into the container at a certain flow rate through the liquid inlet channel. When the content of the filtered dust in the container solution is too high, open the first valve and the second valve to flow out through the first liquid discharge channel and the second liquid discharge channel; S2. Dust-laden gas filtration Keep the first valve on the first liquid discharge channel, the second valve on the second liquid discharge channel and the third valve on the liquid inlet channel closed to ensure that the dust-laden gas is purified by two layers of filter screens; The dust-laden gas enters the bottom of the container from the dust-laden gas inlet channel, and first passes through the coarse filtering surface to filter out larger particles in the dust-laden gas, while also reducing the accumulation of particles in the subsequent filtering process; Afterwards, the dust-laden gas enters the dust removal liquid, forms large bubbles in the dust removal liquid, and rises along with the flow of the dust removal liquid into the super-hydrophilic microfiltration net, at which time the large bubbles are divided into several small bubbles; the fine dust particles are captured by the liquid through the super-hydrophilic surface of the super-hydrophilic microfiltration net, and the dust particles continue to move due to inertia, eventually contacting the gas-liquid interface and being dragged into the dust removal liquid; finally, the filtered dust-laden gas is discharged from the container through the gas outlet at the top of the container.

5. The dust removal method according to claim 4, characterized in that: When the content of filtered dust in the container solution exceeds a set value, the first valve on the first discharge channel, the second valve on the second discharge channel and the third valve on the inlet channel are opened to update the dust removal liquid in the container.

6. The dust removal method according to claim 4, characterized in that: The selection of surfactant is based on dust wetting experiments.

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