Co-combustion of unburned carbon separated from lignite fly ash

Abstract This paper is focused on developing methods of characterization and the technical possibility of co-combustion of unburned carbon separated from lignite. For this aim, sieving technique was developed and a demonstration plant was installed on a 370 MW unit, located at Belchatow Power Station. Three different size fractions of unburned carbon particles separated from fly ash (B08, B10 and B15), raw lignite (WB) and their blends were analysed. Studies indicate that it may be expedient to recycle the smallest fraction of unburned carbon (B08) and further co-combust it with lignite, while largest fractions (B10 and B15) may be considered as valuable materials for preparation of briquettes/pellets and/or activated carbon for flue gases purification. Moreover, performed analyses prove that co-combustion of even 40% contribution of unburned carbons will not considerably deteriorate ignition behaviour, flame stability, fuel burnout, NO X and SO 2 emissions and will not increase slagging and fouling risks.