1. Introduction on Electrostatic Precipitator .

2. EFFECTS OF AIR POLLUTION
HUMAN HEALTH
OCCUPATIONAL SKIN DECEASE
AFFECTS LUNGS - SILICOSIS FOR FOUNDRY WORKMEN
RESPIRATORY CONDITION DUE TO TOXIC AGENTS
ACUTE CONJUNCTIONS DUE TO CHEMICAL DUSTS, FUMES AND GASES
DISORDER DUE TO PHYSICAL AGENTS - ENVIRONMENTAL HEAT OR LOW TEMPERATURE
EYE IRRITATION, COUGH AND BREATHLESSNESS
FORMATION OF CARBOXYL HEMOGLOBIN WHICH PREVENTS O2 CARRIAGE BY BLOOD

3. PURPOSE OF POLLUTION CONTROL EQUIPMENT
Recovery of material for economic reasons
Pulp and Paper Industries (Sodium Sulphate)
Removal of abrasive material in the dust to reduce wear and tear of the Fan components
Removal of objectionable matter in the dust
NO2 and SO2

4. TYPES OF DUST COLLECTING EQUIPMENTS

5. TYPES OF DUST COLLECTING EQUIPMENTS

6. ADVANTAGES OF ELECTROSTATIC PRECIPITATORS
Very high collection efficiency
Low pressure drop
capacity to collect sub-micron particles
Robust construction - Longer life
Less maintenance
Adaptability

7. ELECTROSTATIC PRECIPATATOR
It is a device which captures the dust particles from the flue gas thereby reducing the chimney emission. Precipitators function by electrostatically charging the dust particles in the gas stream. The charged particles are then attracted to and deposited on plates or other collection devices. When enough dust has accumulated, the collectors are shaken to dislodge the dust, causing it to fall with the force of gravity to hoppers below. The dust is then removed by a conveyor system for disposal or recycling

8. LOCATION OF ESP
BOILER
APH
ESP
CHIMNEY

9. ELECTROSTATIC PRECIPITATOR WORKING PRINCIPLE
The precipitation process involves 4 main functions
Corona generation
Particle charging
Particle collection
Removal of particles

10. ESP - CORONA GENERATION
Due to the ionisation of gas molecules, + ve ions, -ve ions and free electrons are generated.

11. CORONA DISCHARGE IN SPIRAL ELECTRODE

12. ESP - PARTICLE CHARGING
The -ve charges of ions and free electrons travel towards +ve electrode and the +ve charges of ions travel towards -ve electrodes.
When -ve ions travel towards +ve electrodes, the -ve charges get attached to the dust particles and thus the dust particles are electrically charged,

13. ESP - PARTICLE COLLECTION

14. ESP - REMOVAL OF PARTICLE

15. Components of ESP Discharge Electrodes Emitting Electrodes
Power Components
Precipitator Controls
Rapping Systems
Purge Air Systems
Flue Gas Conditioning
Emitting Electrodes
Collecting Electrodes
High Voltage Equipment
Rapping Mechanism
Hoppers
Heaters
Gas Distribution Screen

16. Components and their function
Discharge Electrodes: Discharge electrodes emit charging current and provide voltage that generates an electrical field between the discharge electrodes and the collecting plates. The electrical field forces dust particles in the gas stream to migrate toward the collecting plates. The particles then precipitate onto the collecting plates. They are typically supported from the upper discharge frame and are held in alignment between the upper and lower discharge frames. The upper discharge frame is in turn supported from the roof of the precipitator casing. High-voltage insulators are incorporated into the support system.
Collecting Plates :Collecting plates are designed to receive and retain the precipitated particles until they are intentionally removed into the hopper. Collecting plates are also part of the electrical power circuit of the precipitator. These collecting plate functions are incorporated into the precipitator design. Plate baffles shield the precipitated particles from the gas flow while smooth surfaces provide for high operating voltage. Collecting plates are suspended from the precipitator casing and form the gas passages within the precipitator

17. Components and their function
Power Supplies and Controls :The power supply system is designed to provide voltage to the electrical field (or bus section) at the highest possible level. The voltage must be controlled to avoid causing sustained arcing or sparking between the electrodes and the collecting plates. Electrically, a precipitator is divided into a grid, with electrical fields in series (in the direction of the gas flow) and one or more bus sections in parallel (cross-wise to the gas flow). When electrical fields are in series, the power supply for each field can be adjusted to optimize operation of that field. Likewise, having more than one electrical bus section in parallel allows adjustments to compensate for their differences, so that power input can be optimized. The power supply system has four basic components:
Automatic voltage control
Step-up transformer
High-voltage rectifier
Sensing device

18. Components and their function
Gas distribution System: For creating similar gas and dust conditions Uniformity is desired in the following parameters:
Gas velocity
Gas temperature
Dust loading
Gas distribution devices, which ensure this, consist of turning vanes in the inlet ductwork, and perforated gas distribution plates in the inlet and/or outlet fields of the precipitator.
Rapping Systems :  Rappers are time-controlled systems provided for removing dust from the collecting plates and the discharge electrodes. Rapping systems are actuated by electrical, or by mechanical means. Rapping methods include   
Discharge Electrode Rapping : Discharge electrodes should be kept as free as possible of accumulated particulate
Collecting Plate Rapping: Remove the bulk of the precipitated dust

19. Factors affecting ESP Performance
Particle Size Distribution
Gas Speed
Particle Resistivity (can change with presence of sulfur, Moisture,temperature)
ESP Voltage Levels
Re-entrainment of Fly Ash
Rapping Frequency
Fly Ash Properties. (Cohesive Property)
Sparking, back corona and
Particle Loading

20. Bag filter:
Bag filter {also called dry dust collector or fabric filter} are nearly as efficient as precipitator. Bag filter are enclosed housing containing anywhere from several dozen to several thousand fabric filter bag.
The dust-laden air is pushed or pulled through the filter bags causing a dust layer to form on the bag which separate dust from clean air.
The bag are cleaned either by using mechanical shaking or a reverse air process or pulsing using with compressed air.

21. Bag Filter:

22. Bag Filter:
Chimney
Suction Duct
Fan

23. SUITABILITY OF AMMONIA DOSING
Ammonium bisulphate molecules (being adhesive in nature) increases the adhesion strength of dust collected on electrodes and falls in the form of lumps while rapping and thus reduces the re-entertainment loss.
Ammonium sulphate is the outcome of neutralization of excess sulpher present in flue gas.

24. Collecting electrodes
Emitting electrodes

25. Rapping Mechanism

26. THANK YOU