Technology
Wet electrostatic precipitator ( ESP ) particulate control system designs can be either up flow or down flow relative to where polluted air enters the ESP during the particulate control process. Turning vanes and perforated plate evenly distribute the gas flow inside of the wet electrostatic precipitator.
Assuming a down flow design:
The gas then enters the wet electrostatic precipitator (ESP) device’s round collection tubes, which are bundled, between two tube sheets in a honeycomb type arrangement. Above the collection tubes are two sets of spray headers. The first spray header continually mists the collection tubes with small water droplets, which are immediately charged and flow down the tube, in the direction of the gas flow. This continually wets the tubes to prevent sticky particulates from adhering to the tubes during the particulate control process. The second spray header is the flushing header, which periodically sprays a larger amount of water to flush the collected precipitate out of the collection tubes into the lower plenum, during the particulate control process.
In the middle of each ESP collection tube is a rigid pin corona-generating electrode. Each electrode suspends from an alignment rack, which is supported by insulators located out of the gas stream. A 65-80 KV transformer rectifier energizes the electrode rack with an automatic controller. As the dust and aerosol particles enter the collection tubes, located inside of the wet electrostatic precipitator, they become charged from a bombardment of negatively charged electrons. The negatively charged particles adhere to the wetted collection tube and are periodically flushed into the electrostatic precipitator’s lower plenum.
The lower plenum is designed to demist the gas stream and drain all of the collected precipitate to the collection system, completing the particulate control process.
Process
Electrostatic precipitation removes particles from the exhaust gas stream of an industrial process. Often the process involves combustion, but it can be any industrial process that would otherwise emit particles to the atmosphere. Six activities typically take place:
- Ionization – Charging of particles
- Migration – Transporting the charged particles to the collecting surfaces
- Collection – Precipitation of the charged particles onto the collecting surfaces
- Charge Dissipation – Neutralizing the charged particles on the collecting surfaces
- Particle Dislodging – Removing the particles from the collecting surface to the hopper
- Particle Removal – Conveying the particles from the hopper to a disposal point
The major precipitator components that accomplish these activities are as follows:
- Discharge Electrodes
- Power Components
- Precipitator Controls
- Rapping Systems
- Purge Air Systems
- Flue Gas Conditioning
A unique feature of Electro Static Precipitators is the separating force that is applied directly to the particles without the necessity of accelerating the gas as is done for all other particulate collection devices.
This unique feature leads to an extremely low pressure loss for the collection of fine particles compared with that in any other type of collector.
The main features/advantages of ESPs are:
- High collection efficiency is obtained on particles as small as 0.01 micrometer and, with good maintenance, collection efficiency is greater than 99.5%.
- Can collect all types of dust, gas mist, droplets, etc.
- Can collect dust in both wet and dry conditions.
- Can collect all sizes of particles, from microns to coursers.
- Probably the most versatile collecting equipment
- Offers the highest efficiency, can be designed in principle for any efficiency without excessive pressure drop
- Operates with low operation cost
- Can operate over a wide range of inlet conditions, i.e. temperature, pressure, dust burden, humidity, etc.
- Offers negligible pressure drop (rarely crosses 10-15mm)
- Can be built in multiple units, for almost any gas volume
- Has a long life, comparatively free from abrasion effect due to low operating velocity.
- The high recovery value of the dust collected offsets the cost of the equipment.
Applications
Electrostatic precipitation has been a reliable technology since the early 1900’s. Originally developed to abate serious smoke nuisances, the manufacturers of zinc, copper, and lead quickly found electric gas cleaning a cost efficient way to recover valuable product carried out of the stacks from furnace operations.
Today electrostatic precipitators are found mainly on:
- Large power plants
- Cement plants
- Incinerators
- Various boiler applications.
- Galvanizing plants
- Pelettization plants
- Ceramic plants
- Insulators
- Chemical process
Model List
| Model Name | Flow Rate |
| RP – 10 | 10,00,000 kilo calorie / hour |
| RP-14 | 14,00,000 kilo calorie / hour |
| RP-18 | 18,00,000 kilo calorie / hour |
| RP-24 | 24,00,000 kilo calorie / hour |
| RP-36 | 36,00,000 kilo calorie / hour |
| RP-52 | 52,00,000 kilo calorie / hour |
| RP-60 | 60,00,000 kilo calorie / hour |
| RP-70 | 70,00,000 kilo calorie / hour |
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