Electrostatic Precipitators (ESP)

An ESP is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge.

The Electrostatic Precipitators  comes in two variants:

• Dry ESP: used on hot process exhaust (50 – 450˚C) that operate above the dew point of gas stream.
• Wet ESP: used for special applications that require filtering wet, sticky, tarry and oily particulate matter.

Advantage

• Horizontal and Vertical Flow Precipitators
• Dry type design for Gas volumes 5000 Am³/hr to 3000000 Am³/hr
• Wet type design for maximum particulate removal
• Hot gas designs for operation at temperatures above 450°C
• Expertise of top as well as bottom rapping
• Diverse applications like corrosive gas, Over 100 types of dusts, tar, etc

Disadvantages

• ESPs are constant efficiency devices. When the inlet dust load even slightly increases, the outlet emissions may increase.
• High Foot-print area
• ESPs have comparatively higher capital investments

Factors considered for selection of ESP:

• Gas flow – (m3/hr)
• Gas temperature – (Deg C)
• Inlet dust concentration – (gms/m3)
• Required outlet emission – (mg/m3)
• Required collection efficiency – %
• Moisture in gas – %
• Dust composition with components like K2O % and SiO2% in ash – %
• Sulphur content in fuel – %
• Particle size distribution

Various measures that can be undertaken while retrofitting the existing ESP to enhance capacity & lower the outlet emissions:

• Addition of fields for capacity up-gradation / emission reduction.
• Assessment and refurbishment of the ESP system,  refurbishment of damaged field internals&modifications and improvements therein.
• Rebuild configuration with higher collecting area and fields.
• Arrangement utilizing the existing space-to achieve higher collection efficiency.
• Replacement of bottom rapped design with top rapped configurations or improved in-kind type design.
• Splitting of the ESP fields, sectionalisation and addition of new T/R set(s).
• Supply of discharge electrodes to replace existing electrodes of the ESP (any make, any design).
• Relocation and rebuild of the existing ESP.
• New PLC based rapper control panel to replace the older microprocessor based panel.
• Capacity up-gradation – Turnkey Project solutions covering replacement of existing ESP (any make, any design), series or parallel ESP constructions etc.