CN111249836A

CN111249836A - Paint mist wet separation equipment and separation method

Info

Publication number: CN111249836A
Application number: CN202010143108.1A
Authority: CN
Inventors: 何曦; 彭芬; 叶明强
Original assignee: Aerospace Kaitian Environmental Technology Co Ltd
Current assignee: Aerospace Kaitian Environmental Technology Co Ltd
Priority date: 2020-03-04
Filing date: 2020-03-04
Publication date: 2020-06-09
Also published as: WO2021174816A1

Abstract

The embodiment of the present application discloses a paint mist wet separation device and a separation method, which are used to reduce the cost of paint mist treatment and solve the problem that paint particles captured in water are easy to stick to walls. The paint mist wet separation method improved by the embodiment of the present application is to mix the captured water atomized droplets with the paint mist to capture the paint particles, and then rush to the captured water of the tower body at high speed, and the impact generates a large amount of foam floating on the captured water, so as to separate the The paint particles in the captured water are fixed to achieve separation from the captured water, and the separated captured water is atomized and recycled; wherein, the captured water is mixed with a certain amount of surfactant that can enhance the affinity between water and paint particles.

Description

Paint mist wet separation equipment and separation method

Technical Field

The invention belongs to the technical field of paint particle treatment, and particularly relates to paint mist wet separation equipment and a separation method.

Background

Surface coating is an important process in manufacturing industry, and during coating operation, paint forms a plurality of fine paint particles under the action of high-pressure air, most of the fine paint particles are fixed on a workpiece, but a part of the paint particles still float in the air because the paint particles are not fixed on the workpiece in time. The paint particles can cause lung pathological changes and poisoning after being inhaled through respiratory tract, and damage the respiratory system, hematopoietic system and nervous system of human body. At the same time, the paint particles can also promote the generation of photochemical smog. The separation and interception of paint particles have important significance for protecting the ecological environment.

The conventional pretreatment method mainly comprises a dry technology and a wet technology; wherein,

the dry filtration comprises the steps of intercepting paint particles by a filter cotton net, mesh paper, high-efficiency filter cotton and the like, and although the method can partially control the discharge of the paint particles, the filter material is replaced more frequently for enterprises with large spraying amount, and unsmooth exhaust can be caused if the filter material is not replaced in time. Meanwhile, because of the need of setting multilayer filtration, the pressure drop of the exhaust system is higher, the load of the fan is increased, and the operation cost is extremely high.

Compared with a dry paint mist treatment mode, the wet paint mist treatment mode has the advantages of high capture efficiency, stable performance, low operating cost and the like. However, the wet process such as that used in CN2016101679771 generally uses water as a capturing agent, which not only affects the capturing efficiency of paint particles due to the poor affinity of water with paint particles, but also the paint particles captured in water are liable to adhere to the pipe wall of the processing equipment to cause blockage. Meanwhile, after the paint particles are captured by the existing wet process, the water needs to be subjected to flocculation and crosslinking treatment for recycling, which undoubtedly increases the treatment cost.

In conclusion, the existing wet paint mist treatment process has the defects of high treatment cost and blockage caused by easy adhesion of paint particles captured in water on the pipe wall.

Disclosure of Invention

The embodiment of the application provides paint mist wet separation equipment and a separation method, which are used for reducing the paint mist treatment cost and solving the problem that paint particles captured in water are easy to stick to walls.

Therefore, in one aspect, the embodiments of the present application provide a wet paint mist separation method, where the captured water atomized liquid droplets and paint mist are mixed to capture paint particles and then rush to the captured water of a tower body at a high speed, so as to generate a large amount of foam floating on the captured water, so as to fix the paint particles in the captured water, thereby realizing separation from the captured water, and the separated captured water is atomized and then recycled; wherein the capture water has incorporated therein an amount of a surfactant capable of enhancing the affinity of the water for the paint particles.

The inventor further researches and discovers that the addition amount of the surfactant is proper between 0.1 wt.% and 2.0 wt.%, and the foam generated when the addition amount is lower than the range is not enough, so that the de-sticking and separation effects of paint particles are not ideal. When the foam content is higher than the range, the equipment is easily filled with excessive foam, and the load of a subsequent demister is increased. In addition, the impact speed for catching the water atomized liquid drops is properly controlled to be 15-25 m/s, and the excessively low speed is not beneficial to the generation of foam; excessive speed increases processing costs and energy consumption.

In some embodiments, the surfactant is sodium dodecylbenzene sulfonate or cetyltrimethylammonium bromide.

In some embodiments, the paint mist is in the form of a jet that atomizes the captured water into droplets in a venturi throat and mixes and then impinges at high velocity into the tower.

In some embodiments, the paint particles fixed on the foam surface are fished and separated after standing for agglomeration

On the other hand, the embodiment of the application provides paint mist wet separation equipment which comprises a tower body, wherein a venturi contraction pipe is arranged in the tower body, and the tower body is divided into an upper mixing chamber and a lower impact chamber by the venturi contraction pipe;

the small-diameter end of the bottom of the Venturi contraction pipe is connected with a Venturi throat pipe;

the mixing chamber is provided with a capture water inlet and a paint mist inlet;

the capture water in the impact chamber is communicated with the capture water inlet through a circulating pipe with a circulating pump.

The inventor further researches and discovers that the flow speed ratio of gas to liquid in the Venturi throat is optimal between 15:1 and 25:1, when the flow speed ratio is lower than the range, the captured water is difficult to atomize, and when the flow speed ratio is higher than the range, the captured water after atomization is easy to be collected into water flow again.

The surface of the Venturi contraction pipe is uniformly covered by the capture water due to the arrangement of the capture water inlet, the flow speed is not more than 1.0m/s, and the over-high flow speed can cause part of the capture water not to flow downwards along the wall surface of the Venturi throat pipe, so that the atomization effect is influenced.

In some embodiments, an air outlet is provided on the impingement chamber, and an air exhaust fan is provided on the air outlet.

In some embodiments, the exhaust duct disposed on the exhaust outlet is bent upward and then connected to the demister.

Compared with the prior art, the embodiment of the application has the advantages that:

through adding a certain amount of surfactant that can strengthen water and paint particle affinity in catching aquatic, not only solved the paint particle adhesion that is caught in aquatic and caused the problem of jam on the pipe wall, the foam that floats on catching aquatic in a large number that high-speed impact produced can catch the paint particle in aquatic moreover, realize with the separation of catching water, the water of catching need not to carry out extra processing and can realize cyclic utilization.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a paint mist wet separation device provided by an embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the application provides paint mist wet separation equipment and separation method, which are used for reducing the paint mist treatment cost and solving the problem that paint particles captured in water are easy to stick to walls

Referring to fig. 1, a wet paint mist separation method includes that atomized liquid drops of capture water and paint mist are mixed to capture paint particles and then rush to a tower body at a high speed, the paint particles in the capture water are fixed by a large amount of foam floating on the capture water generated by impact, the separation from the capture water is realized, and the separated capture water is atomized and recycled; wherein the capture water is mixed with a certain amount of surfactant which can enhance the affinity of the water and paint particles and can generate foam.

The inventor researches and discovers that the problem of blockage caused by adhesion of paint particles captured in water to a pipe wall is well solved and the capture efficiency of the paint particles is improved by adding a certain amount of surfactant capable of enhancing the affinity of the water and the paint particles into the capture water. The lipophilic functional groups are distributed on the surface of paint particles, are not melted with water, are not easy to be captured by water and have viscosity. The surface active agent has one lipophilic functional group and one hydrophilic functional group, and the lipophilic functional group is combined with the lipophilic functional group of the paint particle to complete the modification (viscosity eliminating) effect.

The inventor further researches and discovers that a large amount of foam floating on the surface of the capture water can be generated by impacting the atomized liquid flow with the captured paint particles when the atomized liquid flow is introduced into the capture water of the tower body at a high speed, the generated bubbles can capture the paint particles in the water, the problem of separation of the water and the paint particles is solved ingeniously, the capture water can be recycled without extra treatment steps such as flocculation, re-crosslinking and the like, and unexpected technical effects are achieved. This is because, as can be seen by analysis, the added surfactant has a very good foaming effect and when rushing into the capture water at high speed, it will impact to generate a large amount of water bubbles, thereby fixing the paint particles.

According to the wet paint mist separation method, a certain amount of surfactant capable of enhancing affinity of water and paint particles is added into the capture water, the problem that the paint particles captured in the water are adhered to the pipe wall to cause blockage is solved, a large amount of foam floating on the capture water generated by high-speed impact can capture the paint particles in the water, separation from the capture water is achieved, the capture water can be recycled without additional treatment, and the paint particles which are not cleaned into the water by the Venturi throat collide with the foam or the tower wall under the action of a flow field and are fixed.

The inventors further investigated and found that the amount of the surfactant added was within the range

The content of the paint particles is between 0.1 and 2.0 wt.%, and the foam generated when the content of the paint particles is below the range is insufficient, so that the anti-sticking and separation effects of the paint particles are not ideal. When the foam content is higher than the range, the equipment is easily filled with excessive foam, and the load of a subsequent demister is increased. In addition, the impact speed for catching the water atomized liquid drops is properly controlled to be 15-25 m/s, and the excessively low speed is not beneficial to the generation of foam; excessive speed increases processing costs and energy consumption.

It should be noted here that the surfactant is various, such as sodium dodecylbenzene sulfonate (SDBS), Cetyl Trimethyl Ammonium Bromide (CTAB), which is selected as the surfactant related to the properties of paint mist, wherein SDBS is an anionic surfactant and CTAB is a cationic surfactant.

In practical application, paint particles fixed on the surface of the foam can form a porous block structure in a standing mode, and the porous block structure floats on the water surface, and then is salvaged to realize thorough separation from captured water.

It can be understood that the paint mist can atomize the captured water into liquid drops in the venturi throat in the form of jet flow, and the liquid drops are mixed and then impact into the tower body at high speed, namely the venturi throat adopts jet flow, and the paint mist is directly used as ejection airflow.

Referring to fig. 1, another aspect of the embodiment of the present application provides a paint mist wet separation apparatus, which includes a tower body 1, wherein a venturi contraction pipe 2 is arranged in the tower body 1, and the venturi contraction pipe 2 divides the tower body 1 into an upper closed mixing chamber 3 and a lower impact chamber 4. Wherein, the small diameter end of the bottom of the Venturi contraction tube 2 is connected with a Venturi throat 5, the mixing chamber 3 is provided with a capture water inlet and a paint mist inlet, and the capture water in the impact chamber 4 is communicated with the capture water inlet through a circulating pipe 7 with a circulating pump 6.

According to the wet paint mist separation equipment in the embodiment of the application, paint mist is guided into a closed mixing chamber 3 at a high speed through a paint mist inlet under the drainage action of a fan, capture water 8 in an impact chamber 4 is pumped into the closed mixing chamber 3 through a circulating pump 6, the pressure of high-speed paint mist airflow is gradually converted into kinetic energy at a contraction pipe due to the reduction of the cross section of a pipe body, the flow speed is accelerated, gas and liquid phases form strong turbulent kinetic energy at the contraction pipe, the turbulent flow cuts, tears and mixes the liquid to form a large number of small droplets (namely atomization), the atomized capture water is further fully mixed with paint particles in a throat pipe and is finally ejected at a high speed through the throat pipe, and a large number of foams 9 are generated on the water surface of an impact groove.

The utility model provides a coating cloud wet process splitter, through adding a certain amount of surfactant that can strengthen water and paint particle affinity in catching aquatic, not only solved the paint particle adhesion that is caught in aquatic and caused the problem of jam on the pipe wall, and the paint particle of aquatic can be caught to a large amount of foams that float on catching water that high-speed impact produced, realize and the separation of catching water, it need not to carry out extra processing and can realize cyclic utilization to catch water, and the paint particle that is not washd to aquatic by the venturi choke collides with foam or tower wall under the flow field effect and is fixed. Compared with the prior art, the equipment structure is simpler and the operation is easier.

Referring to fig. 1, in some embodiments, when the impact chamber 4 is a closed structure, an air outlet may be further disposed on the impact chamber 4, an air blower 10 may be disposed on the air outlet, and paint mist may be introduced into the tower body 1 at a high speed through the air blower 10.

Referring to fig. 1, in other embodiments, in order to prevent the exhaust fan 10 from bringing out a small part of the atomized capture water to the outside of the tower body 1, an exhaust pipe 11 bent upward may be further disposed on the exhaust outlet, a demister 12 is disposed on the exhaust pipe 11, and the exhaust fan 10 is disposed behind the demister 12, so that adverse effects of water vapor on the exhaust fan 10 may be effectively reduced. In the paint mist wet separation equipment, part of water vapor and foam generated by the impact groove are brought into the exhaust pipe 11, the flow speed is reduced when the air flow reaches the upper part of the channel, part of water falls back to the impact groove due to the action of gravity of the brought water vapor, the rest water vapor and foam are intercepted by the demister 12 in the channel and return to the impact groove, and the addition of capture water is not needed basically in the treatment process.

Example 1

The surface modifier is sdbs, the adding amount is 0.5 wt.%, the flow rate ratio of gas to liquid in the Venturi throat is 20:1, the flow rate of fluid at the outlet of the Venturi throat is 20m/s, and the interception efficiency of the tower body on paint particles is 99.06%, 97.18% and 97.75% (three measurements).

Example 2

The surface modifier adopts ctab, the addition amount is 2 wt.%, the flow rate ratio of gas to liquid in the Venturi throat is 15:1, the flow rate of fluid at the outlet of the Venturi throat is 18m/s, and the interception efficiency of the tower body on paint particles is 89.94%, 78.57% and 92.35% (three measurements).

Comparative example 3

The surface modifier adopts ctab, the addition amount is 2 wt.%, the flow rate ratio of gas to liquid in the Venturi throat is 5:1, the fluid impact velocity at the outlet of the Venturi throat is 6m/s, and the interception efficiency of the tower body on paint particles is 22.38%, 23.32% and 20.73%.

The above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Nor is it intended to be exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims

1. a paint mist wet separation method, it is characterized in that: will catch water atomized droplet and paint mist mix and capture the capture water of the tower body after the high-speed rush to the tower body, produce a large amount of foam floating on the capture water, with The paint particles in the captured water are fixed to achieve separation from the captured water, and the separated captured water is atomized and recycled; wherein, the captured water is mixed with a certain amount of surfactant that can enhance the affinity between water and paint particles.

2 . The method according to claim 1 , wherein the addition amount of the surfactant is 0.1 wt. % to 2.0 wt. %. 3 .

3 . The method according to claim 2 , wherein the impact velocity of the atomized droplets is controlled at 15-25 m/s. 4 .

4. The method according to any one of claims 1-3, wherein the surfactant is sodium dodecylbenzenesulfonate or cetyltrimethylammonium bromide.

5 . The method according to claim 4 , wherein the paint mist atomizes the captured water into droplets in the venturi throat in the form of a jet. 6 .

6 . The method according to claim 4 , wherein the paint particles fixed on the surface of the foam are left to stand and agglomerate, and then they are salvaged and separated. 7 .

7. A paint mist wet separation equipment, comprising a tower body, characterized in that: the tower body is provided with a venturi shrinking tube, and the venturi shrinking tube divides the tower body into an upper mixing chamber and a lower part. the impact chamber;

The mixing chamber is provided with an inlet for capturing water and an inlet for paint mist;

The small diameter end at the bottom of the venturi shrinking tube is connected with a venturi throat;

The captured water in the impact chamber is communicated with the captured water inlet through a circulation pipe with a circulation pump.

8 . The paint mist wet separation equipment according to claim 7 , wherein the impact chamber is provided with an air outlet, and the air outlet is provided with an exhaust fan. 9 .

9 . The paint mist wet separation equipment according to claim 8 , wherein the exhaust pipe arranged on the exhaust port is bent upward and connected to the mist eliminator. 10 .

10 . The paint mist wet separation equipment according to claim 1 , wherein the flow rate ratio of gas to liquid in the venturi throat is 15:1 to 25:1. 11 .