The characteristics of electrostatic precipitator, what is the principle of electrostatic precipitat

Compared with other dust removal equipment, the <> electrostatic precipitator has less energy consumption and high dust removal efficiency, which is suitable for removing 0 01-50 m dust in the flue gas, and can be used in the occasion of high flue gas temperature and high pressure. Practice has shown that the larger the amount of flue gas processed, the more economical the investment and operating costs of using the electrostatic precipitator.

Electrostatic precipitator is the use of a high-voltage electric field to ionize the flue gas, and the dust charge in the gas flow is separated from the gas flow under the action of the electric field。The negative electrode is made of metal wires of different cross-sectional shapes, called discharge electrodes. The positive electrode is made of metal plates of different geometries and is called a dust collector electrode.

Due to radiation friction and other reasons, the air contains a small amount of free ions, and it is impossible to fully charge the dust particles in the dusty air by these free ions alone. Therefore, in order to use static electricity to separate dust, two basic conditions must be met, one is the existence of an electric field that charges the dust, and the other is the existence of an electric field that separates the charged dust particles.

The general electrostatic precipitator adopts the method of charging electric field and separating electric field, the metal rod of the discharge electrode is connected to the negative electrode of the high-voltage DC power supply, the dust collection electrode is grounded as the positive electrode, and the dust collector electrode can be a round tube or a flat plate. After the power is turned on, under the action of the electric field, the free ions in the air will move to the poles, the higher the voltage, the higher the electric field strength, and the faster the ion movement.

When all the air around the discharge electrode is ionized, a light blue halo can be seen around the discharge electrode, which is called corona.

The corona range of electrostatic precipitators is usually limited to a few millimeters around the metal rod. After the air is ionized in the corona range, the positive ions will quickly move towards the negative electrode, and only the negative ions will enter the corona outer region and move towards the anode. When dusty air passes through the electrostatic precipitator, due to the small range of the corona zone, only a small amount of dust particles pass through the corona zone and gain a positive charge and are deposited on the corona electrode.

Most of the dust particles pass through the outer area of the corona, acquire a negative charge, and then deposit on the anode plate, when the dust collects to a certain extent, due to gravity, it falls and gathers into the collection tank.

The difference between the water level alone cannot maintain a constant water flow, but with the help of a water pump, a certain water level difference can be maintained and a constant water flow can be formed by continuously sending water from low to high places. Similarly, the electrostatic field generated by the charge alone cannot maintain a stable current, but with the help of a DC power supply, the positive charge can be returned from the negative electrode with a lower potential to the positive electrode with a higher potential by using the non-static electrostatic action (referred to as "non-electrostatic force") to maintain the potential difference between the two electrodes, thus forming a stable current.

The non-electrostatic force in a DC power supply is directed from the negative pole to the positive pole. When the DC power supply is connected to the external circuit, the current from the positive electrode to the negative opening and collapsing electrode is formed outside the power supply (external circuit) due to the promotion of the electric field force. Inside the power supply (internal circuit), the action of the non-electrostatic force causes the current to flow from the negative electrode to the positive electrode, so that the flow of charge forms a closed cycle.

An important characteristic quantity that represents the power supply itself is the electromotive force of the power supply, which is equal to the work done by the non-electrostatic force when the unit positive charge moves from the negative electrode to the positive electrode through the inside of the power supply.

When the internal resistance of the power supply is negligible, the electromotive force of the power supply can be considered to be approximately equal in magnitude to the potential difference or voltage between the two poles of the power supply.

In order to obtain a higher DC voltage, the DC power supply is often used in series, and the total electromotive force is the sum of the electromotive forces of each power supply, and the total internal resistance is also the sum of the internal resistance of each power supply. Due to the increased internal resistance, it can generally only be used in circuits with a small required current intensity. In order to obtain a larger current intensity, the DC power supply with equal electromotive force can be used in parallel, and the total electromotive force is the electromotive force of a single power supply, and the total internal resistance is the parallel value of the resistance in each power supply.

There are many types of DC power supplies, and in different types of DC power supplies, the nature of non-electrostatic force is different, and the process of energy conversion is also different. In chemical batteries (e.g., dry batteries, storage batteries, etc.), non-electrostatic force is a chemical action associated with the dissolution and deposition process of ions, when the chemical battery is discharged, the chemical energy is converted into electrical energy and Joule heating In the temperature difference power supply (such as metal thermocouple, semiconductor thermocouple), the non-electrostatic force is the diffusion effect associated with the temperature difference and the concentration difference of electrons, and the thermal energy is partially converted into electrical energy when the thermostatic power supply provides power to the external circuit. In DC generators, the non-electrostatic force is electromagnetic induction, and when the DC generator supplies power, the mechanical energy is converted into electrical quiet circle energy and Joule heating.

In photocells, the non-electrostatic force is the effect of the photogenerated voltaic effect, and when the photocell is powered, the light energy is converted into electrical energy and Joule heating. If you want to know more about it, you can consult Beijing Oriental Zhongke Integrated Technology Co., Ltd., thank you!

What are the advantages and disadvantages of electrostatic precipitators, the following Zhongda Consulting will answer for you.

The purification efficiency is high, and it can accumulate fine particles of dust above microns. In the design, different operations can be used to remove hail and remove parameters to meet the required purification efficiency.

The resistance loss is small, generally below 20 mm water column, and compared with the cyclone dust collector, even if the power consumption of the power supply unit and the rapping mechanism is considered, its total power consumption is still relatively small.

The permissible operating temperature is high, such as the SHWB circuit dust preferably 250 operating temperature, and other types can reach 350 400 or higher.

Large range of gases to be processed. Automatic control of the operation can be fully realized.

Disadvantages of electrostatic precipitators.

The equipment is relatively complex, requiring a high level of equipment dispatch, installation and maintenance management.

There are certain requirements for the specific resistance of dust, so there is a certain selectivity for dust, and all dust can not obtain high purification efficiency.

Affected by the operating conditions such as gas body temperature and temperature, the same kind of dust is operated at different temperatures and humidity, and the effect obtained is different, and some dust is very good at a certain temperature and humidity, and the electrostatic precipitator can hardly be used due to the change of dust resistance at another temperature and humidity.

The one-time investment is large, and the horizontal electrostatic precipitator occupies a large area.

In some enterprises, the practical effect does not meet the design requirements.

The working principle of electrostatic precipitator electrostatic precipitator uses high-voltage direct current electric field to ionize gas molecules in the air, producing a large number of electrons and ions, moving to the poles under the action of electric field force, and encountering dust particles and bacteria in the air flow to make them charged during the movement process, and the charged particles move to the plates with opposite charges under the action of the electric field force, under the action of the electric field, the free ions in the air should move to the poles, the higher the voltage, the higher the electric field strength, and the faster the movement speed of the ions.

When the flue gas passes through the flue gas in front of the main structure of the electrostatic precipitator, the smoke and dust are positively charged, and then the flue gas enters the electrostatic precipitator channel with multi-layer cathode plates.

The electrostatic precipitator is composed of two parts: one is the electrostatic precipitator body system; The other part is the power supply device and the low-voltage automatic control system that provide high-voltage direct current. The high-voltage power supply system supplies power to the step-up transformer, and the dust collector of the dust collector is grounded.

The low-voltage electric control system is used to control the temperature of the electromagnetic hammer, ash discharge electrode, ash transfer electrode and several components.

The working principle of the electrostatic precipitator is to use the inhomogeneous electric field of high-voltage DC to ionize the gas molecules in the flue gas, produce a large number of electrons and ions, move to the poles under the action of the electric field force, and touch the dust particles in the air flow to make them charged during the movement, and the charged dust moves to the polar opposite polarity of the electrode dust under the action of the electric field force, and the charged dust is adsorbed on the plate or pole line by the electrostatic force when it reaches the plate or pole line, and the dust falls into the ash hopper through the rapping device to purify the flue gas.

Electrostatic precipitator is a kind of gas dust removal method, dust-containing gas is electromagnetically separated by high-voltage electrostatic field, and dust particles are combined with negative ions to carry negative electricity, and tend to be discharged on the surface of the anode and deposited. It is used in metallurgy, chemical and other industries to purify gases or useful dust particles. A dust collection method that ionizes a gas using an electrostatic field so that dust particles are electrically adsorbed onto the electrode.

Electrostatic precipitator (EP or ESP) is a kind of dust removal device that uses electrostatic force to separate particles from gases. When the dust-containing gas passes through the non-uniform high-voltage electric field between the two poles, under the action of the strong electric field around the discharge electrode, the gas is first ionized and the dust particles are charged, and the charged dust particles migrate to the dust collector electrode in the electric field under the action of the electric field force and are deposited on the dust collector, so that they can be separated from the gas and collected, so as to achieve the purpose of dust removal.

The dust removal process of the electrostatic precipitator mainly includes four stages: ionization of gas; The dust is de-energized; Charged dust moves towards the electrodes; Remove the dust from the electrodes into the hopper.

1) Corona discharge and dust particle charge.

Corona discharge. Charge of dust particles.

There are two types of charge mechanisms for dust particles, one is electric field charge and the other is diffusion charge. Electric field charge refers to the way in which the electrons in the corona electric field move directionally under the action of the electric field force and charge the dust particles after colliding with them. Diffusion charge refers to the way in which electrons or dust particles come into contact with the surface of dust particles due to thermal motion, causing the dust charge to roll into bonds.

The way dust particles are charged is related to the particle size.

2) Movement and trapping of charged dust particles.

After the dust particles are charged, under the action of the electric field force, they move to the electrodes of opposite polarity according to the polarity of the charge they carry, and deposit on them.

3) **Removal of dust.

After the dust on the surface of the dust collector electrode is deposited to a certain thickness, in order to ensure the discharge effect and prevent the dust from re-entering the airflow, it needs to be removed so that it falls into the ash hopper, and a small amount of dust will also be attached to the corona electrode, which will affect the size and uniformity of the corona current, and must be removed after a period of time.

The ash cleaning of the corona electrode is generally carried out by mechanical rapping. The extremely clean method is different in dry and wet collectors. At present, most of the electrostatic precipitators use electromagnetic rapping or hammer vibration to clean the ash, and the two commonly used rappers are electromagnetic type and disturbing arm hammer type.

Electrostatic precipitator principle:

1. The electrostatic precipitator adopts the method of charging electric field and separating electric field, the metal rod of the discharge electrode is connected to the negative pole of the high-voltage DC power supply, the dust collection electrode is grounded as the positive electrode, and the dust collector can be a round tube or a flat plate;

2. After the power is turned on, under the action of the electric field, the free ions in the air will move to the poles, the higher the voltage, the higher the electric field strength, and the faster the ion movement;

3. Due to the movement of ions, an electric current is formed between the poles. At the beginning, there are fewer free ions in the air, less current in the spring, after the voltage rises to a certain value, the ions near the discharge electrode gain higher energy and velocity, and when they hit the neutral atoms in the air, the neutral atoms will decompose into positive and negative ions;