CN103008109B - The hollow polar plate electrostatic precipitation device and method that a kind of porous media material is formed - Google Patents

Abstract

The invention relates to a hollow polar plate electrostatic precipitator and method composed of a porous medium material, belonging to the technical field of dedusting. The present invention is characterized in that a hollow pole plate made of a porous medium material is adopted. After water is passed through, the water passes through the porous medium material to form a water film on the surface of the pole plate to trap particles deposited on the surface of the pole plate by the action of an electrostatic field. When the pole plate When there are many particles deposited on the surface that are difficult to remove, the gas is introduced into the inside of the plate, and the gas passes through the porous medium material to form a short gas film on the surface of the plate to remove the particles. Water intake and air supply are carried out alternately. The invention can effectively reduce the water consumption of the wet dust removal, and ensure the complete coverage of the water film of the dust collection plate to realize the purpose of efficient removal of particulate matter. The electrostatic dust removal system using the device has the advantages of compact structure, less water and high efficiency, and easy large-scale application.

Description

Hollow plate electrostatic precipitator and method made of porous dielectric material

technical field

The invention relates to a hollow plate electrostatic dust removal device and method made of a porous medium material, belonging to the field of dust removal technology.

Background technique

A large number of gaseous pollutants and particulate matter produced by human activities are threatening the basic substance that human beings rely on for survival - clean air. Inhalable particulate matter (PM ₁₀ ), especially fine particulate matter (PM _2.5 ) pollution has become a prominent atmospheric environmental problem, and has increasingly attracted great attention from all over the world. Atmospheric particulate matter (especially fine particulate matter) has been recognized as the main cause of increased human mortality. At the same time, atmospheric particulate matter is also the main cause of major air pollution problems such as reduced atmospheric visibility, acid rain, global climate change, and ozone layer destruction. Controlling the pollution of fine particles is a major requirement of the global energy conservation and emission reduction strategy. In a fairly long period of time, the basic situation of fine particulate matter as the primary pollutant of air pollution in my country will not change. At present, China's atmospheric PM _2.5 concentration is several times higher than that of developed countries, which has posed a great threat to human health and economic and social development. The emission control of fine particulate matter is imminent.

At present, although the total particle control technology in the world can reach a very high level, the capture rate of fine particles is very low, resulting in a huge amount of fine particles entering the ambient atmosphere. Taking coal-fired power stations as an example, although the dust removal efficiency of existing dust collectors can be as high as 99%, the capture rate of these dust collectors for fine particles is low. This part of fly ash is dominated by fine particles with a particle size of less than 2.5 microns or even submicrons, which can reach more than 90% of the total number of particles in terms of the number of particles. This is also the reason why China's total suspended particulate matter (TSP) in the atmosphere is declining year by year, and the total amount of particulate matter emissions is also decreasing, but PM _2.5 is on the rise. and a more targeted approach to technological development.

There are more and more researches at home and abroad devoted to improving and optimizing the ability of traditional pollutant control equipment to remove fine particles. For example, improving the fiber material and structure of the filter bag on the basis of traditional bag-type dust removal equipment, and adding intermediate high-energy electrodes on the basis of traditional electrostatic dust removal equipment. Under the more stringent fine particle emission standards, no single removal technology can meet the demand, so it is increasingly urgent to develop collaborative removal technologies with different control methods.

The electrostatic precipitator, which uses electrostatic field as the removal mechanism, is a commonly used flue gas dust removal device at present, and is widely used in electric power enterprises and cement industries. The industrial application of using an electrostatic field to remove particles is mainly to apply electrostatic force directly to the particles to charge the particles and move them to the opposite electrode to achieve removal. In actual operation, high-voltage direct current is often used to generate corona discharge between the two electrodes. When the dust-laden airflow passes through the electric field between the two electrodes, the particles are forcibly charged, and the charged particles move to the polar plate with the opposite polarity under the action of electrostatic force. and is captured by the plates.

The electrostatic precipitator has a good removal effect on large-size particles, but the removal efficiency of small particles, especially fine particles, is not high. In order to better remove fine particles, multi-level electric fields are often set in practical engineering applications to improve the removal efficiency of particles as much as possible. But using this method, the improvement of dust removal efficiency is not obvious. An important reason for this phenomenon is that the fine particles in this particle size range are easy to follow the flue gas flow, the lateral diffusion is weak, and secondary dust may occur. How to enhance the lateral action of the electrostatic field is still an important development direction to improve the capture efficiency of fine particles. At present, the wet electrostatic precipitators that have been industrialized all adopt the technology of applying water film on the polar plate, such as Chinese patents 02222513.7, 00215471.4, 200410058967.1 and so on. The methods of applying water film are all carried out by spraying water on the surface of the plate. In order to avoid the corrosion of the dust collection plate caused by the formation of dry areas on the surface of the plate or the incomplete water film and the low efficiency of dust removal, a large amount of water needs to be sprayed. Maintaining the normal operation of the system will inevitably lead to an increase in water consumption. Chinese patent 20111048292.7 proposes a test device for the dust collecting electrode liquid film of a wet electrostatic precipitator, which can monitor whether there is a dry area problem on the surface of the electrode plate.

To sum up, how to provide a wet electrostatic precipitator that can effectively ensure the complete coverage of the liquid film on the plate, realize efficient removal of particulate matter and reduce water consumption is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The object of the present invention is to provide a hollow plate electrostatic precipitator and method made of porous medium material with low water consumption and high efficiency.

The purpose of the present invention is achieved through the following technical solutions:

A hollow plate electrostatic precipitator made of porous media material, the device includes a plurality of dust collection units and dust collectors, each dust collection unit includes a dust collection plate and a pole line, characterized in that: the dust collection plate is The hollow plate has a hexahedral internal chamber; the surface of the hollow plate is made of porous medium material; the hollow plate is connected to the water inlet valve and the gas supply valve through pipes.

The hollow plate electrostatic precipitator made of porous medium material according to the present invention is characterized in that the porous medium material is made of metal, metal alloy, ceramic, polymer compound, carbon, glass, resin or cotton.

The hollow plate electrostatic precipitator made of porous media material according to the present invention is characterized in that: the porosity of the porous media material is 0.3-0.9, and the average pore diameter is 0.1-100 μm.

The hollow plate electrostatic precipitator made of porous medium material according to the present invention is characterized in that: the internal distance between the surface of the hollow plate and the polar lines on both sides is 10-50 mm.

The present invention provides a method for electrostatic dust removal of a hollow plate made of a porous dielectric material, which is characterized in that the method comprises the following steps:

1) When the air supply valve is closed, the water inlet valve is opened, water enters the hollow plate and fills the entire chamber, water flows out from the pores of the porous medium material and forms a water film on the outer surface of the hollow plate, and is captured by the electrostatic field and deposited on the Collect the particles on the surface of the dust plate and flow into the dust collector of the electrostatic precipitator;

2) When the water inlet valve is closed, after the water in the hollow plate chamber is discharged, the gas supply valve is opened, and the gas introduced passes through the pores of the porous medium material, and the deposited particles on the outer surface of the hollow plate are removed;

3) Repeat steps 1) and 2).

The electrostatic dust removal method for hollow plates made of porous media materials according to the present invention is characterized in that: during the operation of the system, the average gas flow per unit area of the surface of the hollow plates is 0.005-1m ³ / s, the ventilation time is 1-10s.

The electrostatic dust removal method for a hollow electrode plate made of a porous medium material according to the present invention is characterized in that the volume of water in the cavity of the hollow electrode plate is less than 1/3 of the volume of the cavity when gas is introduced.

Compared with the prior art, the present invention has the following advantages and outstanding effects: ① On the premise of not making major changes to the design of the conventional electrostatic precipitator, by replacing the existing dust collecting plate and connecting the water inlet and air supply Pipes and valves can be implemented, which can be conveniently used for design upgrades and device transformations of existing electrostatic precipitators; ②Due to the use of water supply pipes to supply water to the hollow plates, water flows out from the porous media and forms a water film on the outer surface of the hollow plates , to remove particulate matter, no need to set up external nozzles to clean the particulate matter on the surface of the plate, compared with the existing conventional wet electrostatic precipitator, it can reduce the system cost; ③After using porous media materials, the water film on the surface of the dust collecting plate is completely covered, It can ensure a high dust collection efficiency; after the gas is fed into the hollow plate, the gas film formed on the surface of the hollow plate porous medium material can effectively remove the particles adhering to the surface, ensure the effect of dust removal, and reduce water pollution. consumption.

Description of drawings

Fig. 1 is a structural schematic diagram of a hollow plate made of a porous medium material, an air supply valve and a water inlet valve provided by the present invention.

Fig. 2 is a schematic diagram of the arrangement of the hollow pole plate and the pole line when a water film is applied on the surface of the hollow pole plate.

Fig. 3 is a schematic diagram of the arrangement of hollow pole plates and polar lines when a gas film is applied on the surface of the hollow pole plates.

In the figure: 1-hollow polar plate, 2-polar line, 3-water inlet valve, 4-gas supply valve, 5-water film.

detailed description

The principle, structure and working process of the present invention will be further described below in conjunction with the accompanying drawings.

The invention provides a hollow plate electrostatic precipitator made of porous media material, the device includes a plurality of dust collection units and dust collectors, each dust collection unit includes a dust collection pole plate and a pole line 2, and the dust collection pole plate The hollow pole plate 1 is adopted, and its inner chamber is a hexahedral structure; the surface of the hollow pole plate is made of porous medium material; the hollow pole plate 1 is respectively connected with the water inlet valve 3 and the gas supply valve 4 through pipelines. The porous medium material used in the hollow plate electrostatic precipitator is metal, metal alloy, ceramics, polymer compound, carbon, glass, resin or cotton. When flexible materials are used, such as cotton, carbon fiber cloth or glass fiber cloth, a metal frame structure is required to maintain the shape of the hollow electrode plate 1 . The porosity of the porous medium material is 0.3-0.9, and the average pore diameter is 0.1-100 μm. The internal distance between the surface of the hollow pole plate and the polar lines on both sides is 10-50mm.

When the dust collection unit proposed by the present invention is assembled into the overall system of the electrostatic precipitator, the dust collection unit at the end is only provided with a water supply pipe, and no air supply pipe is provided. The main purpose is to avoid the problem that the dust caused by the air supply cannot be captured in the later stage.

Working process of the present invention is as follows:

1) When the gas supply valve 4 is closed, the water inlet valve 3 is opened, water enters the hollow plate 1 and fills the entire chamber, water flows out from the pores of the porous medium material and forms a water film 5 on the outer surface of the hollow plate 1, and is captured by The electrostatic field acts on the particles deposited on the surface of the dust collecting plate, and flows into the dust collector of the electrostatic precipitator;

2) When the water inlet valve 3 is closed, after the water in the cavity of the hollow plate 1 is discharged, the gas supply valve 4 is opened, and the gas passed through through the pores of the porous medium material, and the deposited particles on the outer surface of the hollow plate 1 are removed;

3) Repeat steps 1) and 2).

During the operation of the system, the average gas flow per unit area of the surface of the hollow plate is generally 0.005-1m ³ /s, and the ventilation time is 1-10s.

The volume of water in the cavity of the hollow plate is less than 1/3 of the volume of the cavity when gas is introduced.

In the design of the electrostatic precipitator control system, in addition to the conventional electrostatic precipitator control strategy, the following strategies also need to be considered: the opening frequency setting of the gas supply valve needs to be determined according to the nature of the particles adhered to the surface of the hollow plate. If the plate is corroded or the surface of the plate is damaged, stop opening the water inlet valve, and use intermittent air supply to clean the dust.

Claims (7)

1. the hollow polar plate electrostatic precipitation device of a porous media material formation, this device comprises multiple unit and dust collection of gathering dust, each unit that gathers dust comprises dust collecting pole plate and polar curve (2), it is characterized in that: dust collecting pole plate adopts hollow pole plate (1), and its internal chamber is hexahedron structure; Hollow polar board surface is made up of porous media material; Hollow pole plate is connected with inlet valve (3) and air-supplying valve (4) respectively by pipeline.

2. according to the hollow polar plate electrostatic precipitation device that porous media material according to claim 1 is formed, it is characterized in that: described porous media material adopts metal, metal alloy, pottery, macromolecular compound, carbon or glass.

3. according to the hollow polar plate electrostatic precipitation device that porous media material according to claim 1 is formed, it is characterized in that: the porosity of described porous media material is 0.3 ~ 0.9, and average pore size is 0.1 ~ 100mm.

4. according to the hollow polar plate electrostatic precipitation device that porous media material according to claim 1 is formed, it is characterized in that: the interior surface spacing that hollow pole plate is relative with both sides polar curve is 10 ~ 50mm.

5. adopt a hollow polar plate electrostatic precipitation method for device as claimed in claim 1, it is characterized in that the method comprises the steps:

1) when air-supplying valve (4) is closed, inlet valve (3) is opened, water enters hollow pole plate (1) and is full of whole chamber, water flows out from porous media material hole and forms moisture film (5) at hollow pole plate (1) outer surface, trapping is deposited on the particle on dust collecting pole plate surface by electrostatic field, and flows into the dust collection of electrostatic precipitator;

2) when inlet valve (3) is closed, after moisture in hollow pole plate (1) chamber is discharged, air-supplying valve (4) is opened, and the gas passed into passes from porous media material hole, and is removed by hollow pole plate (1) outside deposition particle;

3) step 1 is repeated) and 2).

6. according to hollow polar plate electrostatic precipitation method according to claim 5, it is characterized in that: in system operation, the gas average discharge that during air feed, hollow polar board surface unit are passes into is 0.005 ~ 1m ³/ s, duration of ventilation is 1 ~ 10s.

7. according to hollow polar plate electrostatic precipitation method according to claim 5, it is characterized in that: when passing into gas, hollow pole plate chamber inner volume is less than 1/3 of chamber volume.