An electrostatic precipitator is defined as a device which is used for the removal of fine particles such as dust and smoke from the flowing gas. Static electricity is used for the removal of dust and smoke.
Working of electrostatic precipitator
The working principle of an electrostatic precipitator is quite simple. There are two electrodes through which the dirty flue gas escapes. The shape of the electrodes is dependent on the electrostatic precipitator. The electrodes can be metal wires, bars, or plates. One of the electrodes is negatively charged, while the other one is positively charged. This helps in attracting the negatively charged particles towards the positive electrode and vice versa. These plates need to be cleaned once in a while.
Effectiveness of electrostatic precipitator
Electrostatic precipitators are exceptionally effective and can remove up to 99% of particulate matter. The effectiveness of the device is dependent on the temperature and moisture of the content of the flue gas.
Properties on which precipitator performance depends
There are two properties which the precipitator performance depends on:
- Electrical resistivity
- Particle size distribution
Following is the table which explains the range of measurement based on the resistivity:
|Resistivity||Range of measurement|
|Low||104 to 107 Ohm.cm|
|Normal||107 to 2 х 1010 Ohm.cm|
|Marginal to high||2 х 1010 and 1012 Ohm.cm|
|High||Above 1012 Ohm.cm|
Characteristics of precipitator
Based on the resistivity, following are the characteristics of the precipitator:
- Low resistivity
- The operating voltage and current of the precipitator are normal and are dependent on the thickness of the dust layer.
- The precipitator is vulnerable to high re-entrainment losses.
- Normal resistivity
- The operating voltage and current are normal.
- The collection performance will be high if the operating voltage and current are normal, and if the voltage drop across the dust layer is negligible.
- Marginal to high resistivity
- The spark rates are dependent on the operating voltage and current levels.
- There is a notable voltage drop across the dust layer.
- High resistivity
- The performance is dependent on the voltage drop and the operating levels of voltage and current.
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