PowerPoint Presentation

ESPThe principal components of an ESP are two sets of electrodes insulated from each other. The first set is composed of row of electrically grounded vertical parallel plates, called the collecting electrodes, between which the dust laden gas flows. The second set of electrodes consists of Tube or wires, called the discharge or emitting electrodes that are centrally located between each pairs of parallel collecting plates.

PRINCIPLEThe wires carry a unidirectional negatively charged high voltage current from an external dc source. The applied high voltage generates a unidirectional, non uniform electrical field whose magnitude is greater near the discharge electrodes. When that voltage is high enough corona is produced around them. Electrical forces in the corona accelerate the free electrons present in the gas so that they ionize the gas molecules, thus forming more electrons & positive gas ions. The new electrons create again more free electrons & ions, which result in a chain reaction.There are four different steps in the process of precipitation:i) Ionization of gases and charging of dust particles.ii) Migration of the particle to the collector.iii) Deposition of charged particles on the collecting surface.iv) Dislodging of particles from the collecting surface

ESP SIZING THOREY

DEUTSCH - ANDERSON EQUATIONCollection Efficiency = 1 - e - w. SCAwhere,w =Migration velocitySCA =Specific Collecting Area Migration Velocity The velocity which the dust particle travel towards the collecting electrode under the influence of electric field.

Specific collecting areaAmount of collecting area required to be provided to collect dust in gas flow rate of 1 m3/s.

CONSTRUCTION DETAILSThe major fundamental parts of the electrostatic precipitator consist of the followingi) Casingii) Hoppersiii) Gas distributor screeniv) Collecting systemv) Emitting systemvi) Rapping mechanism for collecting systemvii) Rapping mechanism for emitting systemviii) Insulator housing.

Casing

The precipitator casing is designed for horizontal gas flow. It is made of mild steel platesThe casing is supported by a number of roller bearings to allow for free expansion due to operating flue gas temparature The casing is insulated by mineral wool and covered with aluminium or GI lining

HOPPERSPyramidal typeHoppers are provided with Baffle Plates Heating elements

Gas Distribution ScreenTo reduce the flue gas velocity

Even distribution of gas.

INSULATORS

SHAFT INSULATORS

SUPPORT INSULATORS

BUSHING INSULATORS

Insulator Housing

Electrical SystemHigh Voltage rectifier transformer

Auxilary control panel

Geared motorsHV RECTIFIER TRANSFORMER

HV RECTIFIER TRANSFORMERRectifier transformer sets are provided on the top of ESP.Rectifier transformer sets are connected to emitting system.Rectifier transformer sets converts 415 A.C voltage to 72 kV DC supply.

Geared MotorsEach emitting and collecting system is provided with one geared motor.

Geared motor unit coupled to rapper shaft and located outside casingAuxiliary Control PanelsHeating for the precipitator hopper

Heating for shaft insulators of the rapping mechanism of emitting electrodes

Heating for the support insulators of the precipitator.Controlling the operation of the rapping motors of collecting and emitting electrodesThank u