Zürich- Hagenholz, CHP Plant: Dry Waste Slag handling retrofit

In August 2015, Magaldi has been selected by Stag AG as the supplier of two air cooled slag removal systems for the Zürich Hagenholz (CH) Waste Incineration Plant.

The patented Magaldi Ecobelt® WA conveyors (to be installed in 2016) are retrofitting the present traditional wet slag removal system, handling and cooling it in a complete dry mode. The Magaldi systems are designed for a material rate of max. 10t/h with the new patented Magaldi Superbelt® reverse version.

The Magaldi Ecobelt® WA is a steel belt conveyor for dry extraction, cooling and handling of bottom ash produced by waste incinerators. Itovercomes the limitation of conventional wet ash extractors (e.g. hydraulic ram feeders or submerged apron-based conveyors) thanks to a combination of the dependable Magaldi Superbelt® technology and a “dry” cooling process. Designed completely enclosed in a steel casing, the Magaldi Ecobelt® WA is suitable to prevent dust or toxic gas dispersion into the environment. Hot ash falls from the combustion grate directly onto the Magaldi Ecobelt® WAthat continuously runs and conveys it to the downstream equipment (e.g. a storage facility or a further dry treatment system). Fine ash particles, passing the combustion grate and collected in the sifting hoppers, can be discharged by gravity through air lock valves onto the Magaldi Ecobelt® WA. Ash cooling is carried out by ambient air, entering the equipment through accurately sized inlet valves located along the conveyor. The amount of cooling air flowing into the furnace is limited by means of suitably designed skirtboards of the steel belt conveyor and special flaps, hinged to the conveyor covers, that allow the ash passage while preventing uncontrolled air backflow to the furnace. Cooling air can be vented to the secondary air fan inlet and then injected into the combustion chamber. The conveyor is designed to promote an intimate contact between air and ash particles, that maximizes the cooling process and the unburned carbon conversion. As a result, the relevant amount of energy, mainly in the form of ash sensible heat, can be recovered to increase the boiler efficiency. Downstream the Magaldi Ecobelt® WA,ash can be released completely dry or conditioned, according to the material characteristics and Client needs.