Short-Rotation Coppice Pellets as Biofuels in a Modern Boiler with an Electrostatic Precipitator: Particulate Matter and Carbon Monoxide Emissions

Alternative pellet feedstocks must be evaluated for energy performance and air pollutant emissions. This study assessed particulate matter (PM) and carbon monoxide (CO) emissions from short-rotation coppice (SRC) pellets combusted in a pellet boiler equipped with an electrostatic precipitator (ESP). Pine and birch pellets served as references. Emissions were measured with and without the ESP and expressed per flue gas volume, fuel energy, and fuel mass. Pellet species significantly affected PM and CO, whereas the ESP significantly reduced PM but did not significantly affect CO. The ESP reduced mean PM concentrations by 52.5%, from 53.81 to 25.54 mg m−3. The highest PM concentration occurred for willow without the ESP (90.96 mg m−3), and the lowest for pine with the ESP (17.51 mg m−3); the highest value was 419.5% greater. Poplar produced relatively low PM but the highest CO emissions. Among SRC fuels, black locust provided the most balanced profile, combining relatively low PM and CO with the highest combustion efficiency (93.20%). Pine and birch, particularly with the ESP, produced the lowest emissions. These findings indicate that SRC pellets showed emission suitability for use in the tested boiler based on PM and CO emission levels.