The MAP® Magaldi Ash Postcombustor is a development of the MAC® system to extract, convey and cool bottom ash, and to enhance and control the postcombustion of unburnt particles on the steel belt in case of biomass / RDF co-combustion in pulverized coal-fired (PCF) boilers.
The option to apply biomass / RDF co-combustion (or co-firing) in PCF power plants can be strongly advantageous for environmental and energy aims. In case significant amounts of unburnt carbon should be extracted together with coal bottom ash, the MAP® system overcomes the limitations of conventional systems: water pollution, energy loss, particle floating in the water bath as well as fines suspended in the water.
The MAP® system aims at enhancing the oxidation of unburnt carbon fraction in “dry” bottom ash. It achieves the greatest advantages where the coarser biomass / RDF fraction (d > 1.0÷2.0 mm) does not have a residence time in the combustion chamber long enough to burn completely. That fraction, due to slower combustion kinetics, falls down in the bottom hopper, appreciably increasing the unburnt carbon content of bottom ash.
The MAP® system can be seen as a system integrated with the boiler, reducing the restrictions about co-fuel size distribution and mixing conditions.