Design of Electrostatic Precipitator for Dust Purification of Electric Arc Furnace
1. Introduction
Electric arc furnace (EAF) is a kind of energy-saving and low-emission metallurgical furnace. It is widely used in metallurgy and other related industries. During the process, a large amount of dust is generated, and there will be adverse effects on environmental health and peoples health. In view of this situation, the dust in the electric arc furnace flue gas needs to be purified by special equipment, and the electrostatic precipitator is a mature and reliable purification equipment.
2. Working principle of electrostatic precipitator
The electrostatic precipitator is a kind of dust removal device that utilizes the electric field effect to remove dust in the flowing flue gas. The dust particles are charged by the corona discharge, and then collect on the electrode plates by the action of the electric field. The flue gas enters the electric dust collector, and the high electric filter plate is energized by the electric field, causing air ions to be produced by the action of airflow. The air ions produce pollutant ions when contacting with the dust particles in the gas. Because of the different mobility of the two kinds of ions, the electric field force is generated to make the pollutant ions move towards the collector plates, attracting the dust particles in the gas and depositing them on the collector plates. The final clean flue gas is released from the other side of the electrostatic dust collector.
3. Design of electrostatic precipitator for dust purification
3.1 Total dust concentration
The total dust concentration of flue gas is an important data for the design of electrostatic dust collector. According to the dust emission concentration and dust emission quantity of electric arc furnace, the total dust concentration of flue gas can be calculated by concentration and volume.
3.2 Principles of selection
In the design of electrostatic precipitator, the selection of filter material, current level, electric field strength, voltage and other parameters is the key to the successful installation. Therefore, when selecting the corresponding parameters, the relevant standards should be fully consulted and the parameters should be selected rationally. Generally, the following parameters should be selected:
(1) Filter material: stainless steel is usually used as the filter material.
(2) current level: usually the current level is selected in the range of 0.5-10mA.
(3) Electric field strength: the electric field intensity of the common electrostatic dust collector is 20-30kv/m.
(4) Voltage: the operating voltage of electrostatic precipitator is usually 180-220kv.
3.3 Pre-treatment device
In the process of purifying the dust in flue gas, the water spray pre-treatment device is often used to reduce the dust concentration and prevent the electrostatic precipitator from being blocked. The nozzle diameter should be selected at 5mm to 10mm, and the precipitation efficiency should be up to 95-98%. The nozzle should be arranged properly to ensure that all the polluted gas is sprayed evenly by the nozzles.
4. Conclusion
Electric arc furnace (EAF) is widely used in metallurgy and other related industries, and a large amount of dust is generated during the production process. The dust needs to be purified by electrostatic precipitator. In the design of electrostatic precipitator, the total dust concentration of flue gas, filter material, current level, voltage and other parameters should be considered, and the parameters must be selected rationally according to the requirements of relevant standards. Water spray pre-treatment equipment is also often used to reduce the dust concentration.
