Electrostatic Precipitators

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lectrostatic PrecipitatorsE

Electrostatic Precipitators are filtration devices that efficiently remove fine particulate from industrial

exhaust emissions with limited influence on the gas flow.

The system “electrode - suspension - rapping” developed by Redecam optimizes the energy applied

to remove the dust and limits its re-entrainment in the gas stream.

Redecam ESP solution can be considered for new installations or to upgrade obsolete filters as well.

Cumra - Turkey

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echanical DesignM

REER, Redecam Rigid Emission Electrodes, are

specifically designed to operate with the highest

available voltages: this allows a full distribution

of the ionisation effect over the entire length

of the electrode.

The system is designed to ensure that the

collecting plates and discharge electrodes

remain perfectly aligned during all operating

conditions.

Specific baffles are fitted inside the hoppers

and along the lateral walls of the ESP to prevent

gas bypassing the treatment zone and dust

re-entrainment phenomena.

Lucena - SpainEmitting electrodes fabrication

Collecting plates ready for shipment

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The rapping action takes advantage of the

sound impact of the cleaning hammers on the

electrodes frames, without risk of damage for

those elements.

Their rigidity avoids any power dispersion

during the hammers hitting, which is evenly

transmitted in the same direction of the dust

particles when they are dropping from the

electrodes.

The electrodes are individually fixed at their top

and only kept aligned at the bottom to ensure

free thermal expansion and a wide flexibility

both during operation and maintenance.

Electrodes rapping: detail of motion trasmission

Rapping system of emission electrodes

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Each electrode can expand independently (this

is not the case when electrodes are installed in

a rigid chassis) and can undertake temperature

rise during operation.

The centreline of each discharge electrode

always remains at the same distance from the

collecting plates (the lack of this condition is

one of the main causes of ESP malfunctions).

Namêche - Belgium

Alignement of electrodes

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The rapping system of the collecting plates

Each electrode can be removed from the

suspending frame, since it is not part of a

rigid chassis, without removing the ESP roof

or creating extra openings.

The profile of Redecam collecting plates

improves the ESP efficiency during the rapping

phase by reducing the re-entrainment of dust

in the gas flow. Plates are suspended at the

top and only kept aligned by a guide frame at

the bottom to maintain their correct position

under all operating conditions.

The mechanism ensures uniform rapping

of each plate at regular intervals. Hammers

are mounted in a staggered position on the

hammer-shaft, so that only few of them impact

at the same time.

Rende - Italy

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HV side of transformer

Supporting insulator: motion trasmission side

Cylindrical porcelain high-voltage insulators

support the discharge electrodes system of each

field. The insulators are installed on the ESP roof

and housed in weatherproof cubicles.

Step-up transformers that convert AC low

voltage (400-500 V, 3 phase) into DC high

voltage (110 kV) supply the power to the ESP.

The self-contained, weatherproof transformers

are oil insulated and include rectifying bridges.

In order to shorten the HV cable length, the

transformers are normally placed on the roof of

the ESP.

Units are supplied with a master switchboard

and a digital panel to provide the ESP’s typical

control functions:

• current and voltage regulation within the

optimal operation range according to operating

conditions of the plant

• protection against possible overload

• automatic restart of the system after any shut-off.

Electrostatic precipitator control cubicle

lectrical EquipmentE

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esign ParametersD

The definition of the ESP features (dimensions,

number of fields, surface area of the

collecting electrodes) are based on the process

parameters, i.e. temperature, capacity and

chemical composition of the gas flow.

Physical and chemical properties of the dust

(type, size, concentration) are also important

ESP design parameters. Moisture and

temperature have an important impact on the

dust resistivity, which significantly affects the

collection efficiency and the formation of the

dust layer on the collecting plates.

The specific collecting area and the gas

velocity through the ESP casing must be

carefully evaluated in order to design an

efficient dust collector. The distribution of the

gas flow across the ESP is a further critical

parameter that can affect the efficiency of the

filter. Fluid distribution inside the filter must

be homogeneous to obtain uniform velocity;

when an odd gas distribution leads to exceed

the design speed, the effect on the collection

efficiency is detrimental.

For analogue reasons inlet and outlet of the

ESP must be properly designed to provide

an even flow of the gas to prevent excessive

pressure losses.

Cuneo - Italy

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odellingMFor several years, Redecam has been modelling

through physical simulation on 1:7 scale

models. Large scale models are needed to

respect the laws of physics and to keep the

process parameters consistent (e.g. Reynolds

number, operating pressure).

All models have been made and tested in

Redecam’s workshop, with its own equipment

and internal engineering resources.

Recently, increased modelling demand led

to extend the action field to the numerical

simulation. This approach allowed Redecam to

reach a sound control of all critical parameters

involved in the process. The same would not

have been possible with a direct approach.

Numerical simulation of inlet perforated plates

Numerical simulationof gas flow

distribution inside electrostatic precipitators

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n-Site ActivitiesO

Redecam’s focus is on serving the industrial

sectors with a wide range of solutions and

services. Scope of work can be extended to a

turnkey solution including electrical and civil

work, or be limited to the engineering design

using local fabrication and supply of the critical

components.

Our solutions can be designed for installation

in existing plants, making “upgrades” or

“retrofits” of obsolete equipment, or designing

a complete replacement.

Each case is carefully evaluated and the resulting

solution is always custom-made.

Two sections lifting

Heavy lift during dark night

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Tepetzingo - Mexico

Redecam GroupPiazza Montanelli, 20 – 20099 Sesto S.G. - ItalyPh. +39 02 243491 fax +39 02 24349100www.redecam.comemail: redecam@redecam.com