Co-combustion of refuse derived fuel with Korean anthracite in a commercial circulating fluidized bed boiler

The effect of co-combustion of Refuse Derived Fuel (RDF) with Korean anthracite on the combustion and environmental performance was observed in the Tonghae commercial Circulating Fluidized Bed (CFB) boiler. High contents of oxygen and CaO in RDF reduced the amount of air required for combustion and the limestone flow rate for SO2 capture in the CFB boiler, respectively. The temperature in the furnace exit increased slightly due to re-combustion of volatiles which resulted in limiting the co-combustion ratio of RDF for the CFB boiler to operate stably. With the increasing co-combustion ratio of RDF, the output voltages of electrostatic precipitator (EP), which consists of 2-channels and 5-stages collecting plates, decreased linearly. Eventually, stability of the EP could not be maintained above 5% of the RDF co-combustion ratio. The emissions of NOx, HCl and dioxin during co-combustion did not change appreciably as compared to the case when Korean anthracite was burnt alone, which were also low enough to meet Korean emissions limits. On the other hand, chlorine contents in ashes emitted from the CFB boiler increased gradually with the increasing co-combustion ratio, which implied that most of chlorines were fixed by limestone.