Lodge Cottrell of Birmingham carried out the work as part of a three stage programme designed to improve particulate emissions at the 1500 MW coal burning station.
In the first stage of the programme the precipitators for boiler Unit 3 were upgraded. The work was carried out over a 15 week period that coincided with the boiler's statutory outage programme. Similar work was undertaken on Unit 1 boiler followed a year later with the upgrade to Unit 2.
A spokesman at Lodge Cottrell, explained: " The challenge at Kingsnorth was to cost effectively increase the performance of the electrostatic precipitators within the existing precipitator area and to carry out the work with no disruption to the station's capability to supply electricity." He continued: "Both Powergen and ourselves understood right from the start that advance planning was key to the success of such an undertaking and we have worked very closely throughout."
It was decided to upgrade one unit each year over a three year period and Lodge Cottrell engineers devised a method of adding precipitator capacity to the existing units by increasing their collector height to achieve dust emissions of less than 50mg/Nm³.
The scheme put forward by Lodge Cottrell, and supported by new performance guarantees, involved removing the roof and internals of each precipitator and extending the height of the original casing. New and taller catch space collectors are then installed and a new roof and top housing constructed.
Also included as part of the improvements is an enhanced flue gas distribution system and new electrical energisation and control systems.
"The upgraded units are achieving emission levels well in advance of statutory requirements and Lodge Cottrell completed the project in the agreed time schedule", explained Garnet Jones, Powergen's Project Manager.
Lodge Cottrell employs a variety of technologies to increase the performance of existing electrostatic precipitators. These often require site specific solutions and depend on factors such as location, space availability, coal used, outages available and emissions required.