Possibility of Using Spent Coffee Grounds as a Fuel for Co-Firing Application

The possibility of co-firing spent coffee grounds (SCG) with pulverized coal was investigated with a pilot combustion test facility in terms of pulverization performance, combustion and emission characteristics. A coal and two SCG-coal blends having SCG 5 and 10 wt. % in the blend were used for the tests. The thermal behaviors of fuels tested were also evaluated with a thermogrvimetric analyzer.The pyrolysis and combustion behaviors of SCG were very similar to those of woody biomass. The addition of SCG to coal decreased the activation energy of the blend, and improved the reactivity during pyrolysis and combustion. The pilot mill tests showed that SCG-coal blends, compared to coal, produced the higher pressure difference in the mill, and subsequently resulted in the higher mill power consumption, the less amount of fuel pulverized and the finer particle size distribution. The co-firing of SCG with coal improved the burnout of coal and increased gas temperature in the pilot test furnace, and NOx and SOx emissions were somewhat increased, compared to those in solely burning of coal.