Over the years Kopar has become a major supplier and expert of ash handling system for power plants. Particularly plants that use coal or peat as the prime energy source need efficient systems to handle ash in ways that are fast, reliable and cost-effective.
The most recent Kopar innovation in bottom ash handling is a more efficient cooling screw that is used to move the hot ash from under the boiler to drag chain conveyors and further handling. Kopar also supplies the heavy-duty drag chain conveyors.
The cooling screw is an important device in cooling off the ash coming from the fluidised bed or some other type of furnace. The ash temperature may vary between 400ºC and 800ºC and the sooner the ash is cooled the better for the plant's operation and particularly to the equipment near the screw.
The new Kopar screw can be supplied in different lengths, ranging typically from 4m to 8m. In the ash receiving end of the screw, the flight pitch is tighter to act similar to a crusher and prevents clogging as a result. The screw can be opened for easy servicing or removing the occasional oversized material.
The major difference in efficiency is that the ash is mixed better than by traditional screw constructions. Because ash itself provides a relatively good isolation, it brings along the problem that the hot ash is cocooned inside the cooler material.
An improved mixing, as in this case, enables the hot ash to have a better contact with the cooling area and results in smaller dimensioning. The cooling elements are all in different circuits, which raise the cooling capacity and help to adjust it in operation. It is also possible to use the cooling water from the screws to optimise the plant output.