During this phase, GE will convert two electrostatic precipitators from tumbling hammer to GE’s top rap technology. GE commenced work on the four units at this power station in 2003, in a phased approach, during the now completed rehabilitation project of the power plant.
Electrostatic precipitators collect airborne particulates using electrical current to deposit the particles on large steel surfaces inside the precipitator. To maintain the collection efficiency of the system, the collector plates and high-voltage discharge electrodes need to be regularly cleaned of dust by a rapping system.
Cleaning on the original units at Maritza used rotating hammers mounted inside the precipitator. The hammer train components are exposed to the flue gas and suffer wear in the hostile environment, GE said. Having the rotating hammer train inside the precipitator precludes maintenance while the precipitator is on line, resulting in unplanned outages to repair the hammer trains.
GE’s top-rap design mounts the rapping devices externally on the roof of the precipitator, allowing maintenance to the rappers while the precipitator is online.
This latest contract will convert fields 1 and 2 of the unit 2 precipitator to help achieve emissions below 50 mg/Nm3 (dry at 6% O2). GE bagged the contract to rebuild fields 1 and 2 of the unit 1 precipitator in November 2008, and the project was completed in August 2009.
Currently, fields 1 and 2 are configured as a rigid emitter frame tumbling hammer design. GE previously reconfigured fields 3 and 4 of the unit 2 precipitator to a top-rap design. As part of the new contract, the two inlet fields will be converted to the same top-rap design with components supplied by GE.
Mark Hachenski, product general manager of GE Energy Services, said: “Our proven technology and commitment to service has allowed us to be successful in the previous stages of the Enel Maritza East 3 project. Within the framework of the new contract, we will continue to work with Enel to meet the plant’s emission reduction needs.”
As part of the contract, all existing internal components will be removed to accommodate the new parts. The existing casing, inlet transition, outlet transition, hoppers, and structural supports will be reused as part of the rebuild scope.
