Refuse-Derived Fuel and Integrated Calcium Hydroxide Sorbent for Coal Combustion Desulfurization

Pelletized refuse-derived fuel (RDF; 65 wt % nonrecyclable fibers/plastics) and integrated calcium hydroxide sorbent (35 wt %), referred to as a ReEngineered Feedstock (ReEF), were evaluated as a renewable fuel and an in situ sulfur sorbent within pulverized coal combustion. Characterization of ReEF with scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated random distribution of calcium hydroxide sorbents on fiber/plastic particles. The sulfation kinetics of ReEF combustion were evaluated in a drop-tube reactor at variable conditions (800–1000 °C, 1400 ppm of SO2, and 5–30% O2 in N2) with continuous effluent characterization via online IR spectroscopy. Sulfation of calcium hydroxide in ReEF was delayed because of RDF combustion when compared with pure calcium hydroxide sorbent. A low-O2 condition was shown to produce high conversion of calcium hydroxide to calcium sulfate (XCa(OH)2 > 0.4), while calcination and combustion of ReEF in a high-O2 environment (O2 > 20%) resulted in incre...