The coal-fired heat & power plant of ZEC Bydgoszcz supplies electricity to the grid and district heating of Bydgoszcz, a town in the north-west of Poland. The submergedchain conveyor (SCC) systems for bottom ash handling needed extensive waste water treatment with relevant ash ponds. Moreover, in the winter period, ice formation caused serious operating problems.
With environmental legislation on water quality becoming even stricter, ZEC decided to eliminate all water related problems by adopting the MAC® (Magaldi Ash Cooler) system for the wet-to-dry conversion of bottom ash handling systems on Units #3 & 4.
The MAC® systems provided the following main benefits to ZEC Bydgoszcz:



PGE Mining and Conventional Power SA - a branch team of the Bydgoszcz power plant, on the basis of concessions granted by the President of the Energy Regulatory Office, does business in the following areas: generation, transmission and distribution,of,heat,and electricity.
The branch team of the Bydgoszcz power plant consists of three units:
Unit #I – currently supplying heat to the western and central part of the town of Bydgoszcz;
Unit#II - is the primary heat and electricity source of the town,
Unit #III - located in the premises of Infrastruktura KapuĊ›ciska SA, as part of the BydgoszczII power plant.



The MAC® system is placed directly under the boiler throat and extracts approx. 1.5 t/h of bottom ash. Although there is no bottom hopper, the MAC® system can be operated both continuously and intermittently. Normally, during the night shift the system is stopped and the bottom ash is stored on the conveyor.
After re-starting the system in the morning, the bottom ash is extracted and the system runs continuously throughout the day. After crushing and further conveying by a Postcooler, the bottom ash is pulverized by a hammer mill and then pneumatically conveyed to the fly ash storage silo. An alternative discharge route through an ash conditioner onto open trucks is provided, allowing the running of the hammer mill and the pneumatic system with the boiler in operation. Mixing of the bottom ash and fly ash is possible due to its fineness obtained in the pulverization stage and the low unburnt carbon content in the bottom ash.
In fact, unburnt residues drop from 8% with the wet system down to only 2% after the installation of the MAC® system. In this way, the bottom ash was turned into a more valuable by-product. Another advantage, reported by the plant operators, is the possibility of being able to visually check the quality and quantity of the bottom ash leaving the boiler throat through the inspection windows installed on the MAC® extractor. Thanks to this, a better understanding of the effects of the boiler operation on the ash formation was achieved, reducing the problems of boiler slagging.