Electrostatic precipitator is one of flue gas filter equipment in boiler. There are some choices to determine flue gas filter equipment. There are multi cyclone, bag house and electrostatic precipitator. Basic working principle of electrostatic precipitator is passing the exhaust gas or flue gas (product of combustion from furnace boiler) to the room which containing the electrode plates, made of copper or brass.
Attached electrodes in the construction of electrostatic precipitator is energized by direct current electric (DC) with positive and negative charges. Between the electrode trunks which has negative charge and plate dust collector which has positive charge is energized by voltage 70-90 KV. The grains of dust that pass through the electrode trunk will be induced by negative charge and so now the grains of dust have negative charge. Because their charge is negative, the electrode plate which has positive charge attracts the grains of dust so the grains of dust stick to the plate.
Presence of vibration (rapping) that touch the plate dust collector will cause dust fall into dust hopper, then the dust will be separated from flue gas in the electric precipitator. By passing static electric current will precipitate dust effectively so the impact of air pollution can be eliminated. This method can reach efficiency above 90% and can capture small particle dust until less than 2µC. Electrostatic precipitator can be applied to cement plant, pulp and paper plant and power plant.
The factors that determine the selection of flue gas filter equipment in boiler are as follow:
- The efficiency to filter dust particle
- The size of captured dust particle
- The fuel used in the combustion furnace
- Capacity of fuel in the combustion furnace
- Development and maintenance cost