In the last years the respect for the environment has become the main target for many power plants in the world. At the present time all the efforts are focused on the emission reduction (CO2, NOx, SOx, particulates, etc.) and on the valorisation of the ash considered as a waste till few years ago.

These problems are amplified for the power plants provided with solid fuel fired boilers. Besides, some years ago, there have been effected international standards that regulate the possible uses of the ash as a constituent of cements (ENV 197-1) and concretes (UNI-EN 450). In this way the ash is not a waste anymore, but it can be considered as a source of useful by-products if it respects the limits specified in the above mentioned standards.

In order to reduce these environmental impacts and to make ash usable in cements or concretes, MAGALDI has developed and patented a system able to extract, cool and recycle into the combustion chamber, the ash coming from solid fuel fired boilers. This new system combines the MAC® (Magaldi Ash Cooler) System and its development, called MAR® (Magaldi Ash Recycling) System, resulting in an integrated MAC® + MAR® System.
The MAC® System allows to extract, convey and cool the bottom ash of a solid fuel fired boiler in a completely “dry” way, while the MAR® System recycles into the combustion chamber the dry bottom ash mixed with high unburned content fly ash.

Particularly, the main targets of this new integrated system are:

1. Dry extraction of bottom ash with no use of water for ash cooling and conveying

2. Bottom ash elimination through the recycling into the combustion chamber

3. UBC reduction in the fly ash