Development of a Sludge Slagging Combustor

Kobe Steel has developed a sludge slagging combustor (1). The main features of this combustor are the use of swirling flow combustion and two-stage air injection. Swirling flow combustion increases the combustion intensity, dust collection and retention time. Two-stage air injection produces a desirable flow pattern and temperature distribution. Additional fuel is added in order to keep the wall temperature of the slagging combustor uniform at above one hundred degrees higher than the ash fusion temperature. The sewage ash melts quickly after entering the slagging combustor. The slag capture for ash is over 95%, and the NOx emission is less than 100 ppm corrected to 12% Oz. A heavy metal water-miscible test indicates no problem with slag disposal and a strength test indicates that the slag can be used as a construction material. The sludge slagging combustor has been applied to a 40 ton-cake per day Melting After Carbonizing Sludge system commercial plant. The expected performance of the slagging combustor is comfirmed by the commercial plant operation.