Combustion and Emission Analysis of Spent Mushroom Compost and Forestry Woodchip for Management and Energy Production

Forestry woodchip and spent mushroom compost have commercial potential as sustainable residues in biological and chemical processes for energy production. This study focuses on the evaluation of agri-food industry waste energy valorization, with the aim to reduce the valuable biomass utilization for energy production without decreasing the process quality, thereby pursuing economic and environmental advantages. Burning trials were conducted in a fluidized bed biomass plant provided with emission abatement systems. The biomass mixture used for combustion was composed of pine and oak woodchip and spent mushroom compost. The biomass used was first characterized through compositional and energetic analysis, and subsequently, during the burning tests, a monitoring sampling campaign was carried out to analyze the gas and particles emission. Optimal combustion conditions were observed during combustion, with good oxidation of the organic material, relatively high CO2 production, and low CO concentration in flue gas. Nevertheless, SO2 concentrations in the combustion flue gas are greater than those found in the combustion of the most commonly used biomasses. In fact, the mixture compositional characterization revealed a non-negligible concentration of sulfur, which explains the high values of SO2 detected in emission. The obtained results confirm that controlled combustion, together with suitable biomasses utilization, preliminary characterization, and emission monitoring, are essential practices for the realization of a sustainable process, both from an energy and environmental point of view