The Burning Properties of Dust from Asphalt Firing in Pulverized Coal Fired Boilers

Since ashes from heavy oil or asphalt fired boilers contain considerable amount of corrosive materials, they are burned with additional oil in an exclusive incinerator. On the other hand, as they includes much unburned carbon having as much heating value as coal, there is some possibility to use them as fuel. In this study, ashes sampled at the electrostatic precipitator (EP) of an asphalt-fired boiler were examined whether they could be co-fired in the pulverized-coal-fired boilers. From laboratory-scale and pilot-scale test results it was made clear that although the ashes from asphalt firing had as only as a little amount of volatile matter as semianthracite or anthracite had, they revealed burn-out properties Iike bituminous. When they were co-fired with pulverized coal by 1% by heat input, a considerable increase in SO, emission was noted, whiIe N0X emission was somewhat decreased compared with coal firing. From these verifications, it was confirmed that the co-firing of ashes from asphalt firing with pulverized coal was applicable to actual boilers within the permitted S02 concentration at the inlet of the de-SOx system.