Prediction of organic aerosol precursor emission from the pyrolysis of thermally thick wood

Abstract

Primary organic aerosols (POA) are abundant in the atmosphere. POA are mainly emitted during the pre-ignition phase of wood combustion. In this work we demonstrate that the thermal degradation of wood that occurs during pre-ignition can be understood and predicted using pyrolysis modeling. We model the pyrolysis of 14 × 3.8 × 2.9 cm maple wood samples using Gpyro software to predict the emission of classes of gaseous products throughout the process. We define two classes of gases emitted that can be predicted by the model: light and heavy gases, where heavy gases include OA precursors. The validation experiments of wood pyrolysis were performed in a cylindrical reactor of the wood samples at three temperatures 400, 500, and 600 °C. Temperature and mass change were predicted by the model. The release rate of gaseous products showed two peaks, that were due to heat transfer at the surface and pressure evolution at the center. The validated model enables the comparison of atmospherically relevant quantities predicted in the model with emission data from atmospheric studies. The predicted emission factor of heavy gases occurring before the first peak of release rate can account for the measured POA emission factor from wood combustion during the pre-ignition phase.