CEM - Abstract

Abstract Information :

Biomass combustion is the main source of renewable energy used in France, but this is also the first source of particulate matter (PM) emissions to the atmosphere, mainly due to domestic wood combustion (42% of PM2,5 emissions in 2020, Citepa inventory). This significant contribution of biomass combustion to PM national inventory addresses the issue of emissions from small-sized wood boilers (power output below 1MW). In France, until 2018 and the recast of the combustion regulation, boilers with a power output of less than 2MW were not subject to emission monitoring requirements. Since the order of August 3, 2018, regulatory control every 2 years for emissions of O2, SOx, TSP, CO, OGCs, NOx, dioxins and furans are required for biomass combustion facilities down to 1 MW power output. For combustion facilities which are not subject to regulatory controls two decrees (the decree of September 15th, 2009, and the decree of October 2nd, 2009) provide target value to be reached in terms of particulate emissions of 80 mg Nm-3 and 225 mg Nm-3 at O2 6% (respectively) and for the dimensioning of the filtration system by manufacturers. The French Biomass Heat Fund (BHF) developed by ADEME (The French Agency for Ecological Transition) in 2009 to consolidate on the territory, the installations of production of renewable heat and recovery and the development of the heating networks also provides limit values. The BHF concerns projects producing more than 1200 MWh/year (400-600 kW). For boilers between 500 kW and 1MW, the BHF requires 50 mg Nm-3 for TSP, 500 mg Nm-3 for NOx and 250 mg Nm-3 for CO (at O2 6%). It is in this regulatory context that ADEME, wished to associate three French partners (Indiggo, Ineris and Citepa) within the ACIBIOQA national project (agreement number 1903C0042) to carry out measurements of the emission of biomass boiler of power output below 20MW. The emissions of six biomass boilers with power output comprised between 150 kW and 1.65 MW distributed on the French territory were characterised. The measurement campaigns focused on the emissions of TSP (solid and condensable), PM10, PM2.5, PM1, Black carbon, 9 heavy metals, 8 PAHs and combustion gases (O2, CO2, CO, NOx and OGCs). The measurement results varied according to the power of the boiler, the flue gas treatment implemented, and the sizing of the boiler combustion chamber according to the energy needs. This study which provides essential knowledge on the emissions from biomass boilers with power output below 1 MW in France, was also a first attempt of characterization of the condensable fraction PM emitted by such sources.