How do electrostatic precipitators, scrubbers and catalytic converters prevent pollution?
How do electrostatic precipitators, scrubbers and catalytic converters prevent pollution?
electrostatic precipitator (ESP)
An electrostatic precipitator (ESP) is an electro-mechanical device which filters out particles (fly ash/Fumes/Suspended dirt) from air/gas stream (flue gas if from a boiler or furnace) before releasing out of a chimney. The principal is using Electrostatic force of a very high voltage negative charge (DC). The negative charge is achieved using a Transformer-Rectifier Set (TR set).
There are mainly 3 main parts to an ESP:
- Emitting Set (Negative electrodes set) - Which get negatively charged from TR set. It is isolated from remaining ESP by using insulators of various types at inersection points. The electrodes upon charged generate an electric field around the electrodes, called as “Corona” effect.
- Collecting Set (Positive Electrodes Set) - This is mainly to collect the desired particles. Unlike popular notion, there is no “positive” charge in it, this is simply attached to ground to have zero charge. Since zero is higher than negative, it acts as a positive electrode. These are a set of flat plates placed in front of Emitting electrodes.
- Rapping Mechanism - The collected particles which cling to Emitting or Collecting set are brought down by “rapping”, periodical forceful removal of particles by hammering/vibrating the body. Usually rappers vary from make to size in ESP’s.
Working of ESP:
When the stream of gas/air loaded with particles enters the ESP, it is evenly distributed across the spectrum using a perforated giant screen called as Gas Distribution screen. The stream as perforated crosses the ESP in between sets of two Collecting plates with charged Emitting Electrodes in between.
The incoming neutral particles gets “ionized” at Corona, to negative charge. Containing the negative charge, they get attracted to collecting plate and fly towards it. Upon sticking with Collecting plates they gets shaken down by the Collecting Rapping mechanism.
Also some particles which loose their charge at collecting plates (again becomes neutral), gets attracted towards Emitting again and stick there are shaken down using Emitting Rapping mechanism.
Conveying System
The shaken down particles are collected at bottom hoppers which are further conveyed for disposal.
electrostatic precipitator (ESP)
An electrostatic precipitator (ESP) is an electro-mechanical device which filters out particles (fly ash/Fumes/Suspended dirt) from air/gas stream (flue gas if from a boiler or furnace) before releasing out of a chimney. The principal is using Electrostatic force of a very high voltage negative charge (DC). The negative charge is achieved using a Transformer-Rectifier Set (TR set).
There are mainly 3 main parts to an ESP:
- Emitting Set (Negative electrodes set) - Which get negatively charged from TR set. It is isolated from remaining ESP by using insulators of various types at inersection points. The electrodes upon charged generate an electric field around the electrodes, called as “Corona” effect.
- Collecting Set (Positive Electrodes Set) - This is mainly to collect the desired particles. Unlike popular notion, there is no “positive” charge in it, this is simply attached to ground to have zero charge. Since zero is higher than negative, it acts as a positive electrode. These are a set of flat plates placed in front of Emitting electrodes.
- Rapping Mechanism - The collected particles which cling to Emitting or Collecting set are brought down by “rapping”, periodical forceful removal of particles by hammering/vibrating the body. Usually rappers vary from make to size in ESP’s.
Working of ESP:
When the stream of gas/air loaded with particles enters the ESP, it is evenly distributed across the spectrum using a perforated giant screen called as Gas Distribution screen. The stream as perforated crosses the ESP in between sets of two Collecting plates with charged Emitting Electrodes in between.
The incoming neutral particles gets “ionized” at Corona, to negative charge. Containing the negative charge, they get attracted to collecting plate and fly towards it. Upon sticking with Collecting plates they gets shaken down by the Collecting Rapping mechanism.
Also some particles which loose their charge at collecting plates (again becomes neutral), gets attracted towards Emitting again and stick there are shaken down using Emitting Rapping mechanism.
Conveying System
The shaken down particles are collected at bottom hoppers which are further conveyed for disposal.
