Performance Assessment of Invasive Acacia dealbata as a Fuel for a Domestic Pellet Boiler

Abstract

The use of alternative energy sources becomes ever more important due to the necessity to minimize the energy consumption of fossil fuels and fight climate changes. This study evaluates the combustion and emissions characteristics of a commercial wood pellet boiler with a nominal thermal output of 20 kW using purposed-manufactured Acacia dealbata pellets. Previously, the boiler was tested burning commercial Pine pellets that were used to benchmark the Acacia pellets. The thermal efficiency and emissions of the invasive species pellets were compared at three different predefined operation loads. The efficiency of the boiler was determined using the direct method. The obtained results show that, for the same fuel mass flow rate, the best boiler efficiency was always achieved with Pine pellets. Nonetheless, invasive species pellets deserve some credit if the boiler combustion conditions are adopted to that specific type of fuel. Concerning emissions, CO and NOx resulting of burning Acacia pellets were significantly higher than burning Pine pellets. Overall, the type of pellets had a significant effect on the boiler performance, mainly on emissions.