Biomass burning emissions and influence of combustion variables in the cone-calorimeter
Summary, in English
In this study, we used a controlled atmosphere cone calorimeter according to ISO 5660‐5. We controlled fuel moisture content, the air flow to the combustion and O2 available for combustion, and the total heat flux (HF) to the fuel to study the independent effect of combustion variables on the aerosol emissions. In each experiment a small 10x10x1 cm piece of Birch-wood was put in a sample holder and combusted under controlled conditions. We conducted over 40 experiments, varying HF and flow conditions while monitoring fuel mass loss to quantify emission yields. An Aerosol Mass Spectrometer (AMS, Aerodyne Billerica, USA), a multi‐wavelength aethalometer (AE33, Magee Sci., USA) and a particle size spectrometer (DMS5000, Cambustion, UK) measured time‐resolved evolution in particle properties during burns.
Our results showed that pyrolysis conditions in the absence of O2 resulted in organic aerosol (OA) emissions with mass yields (g/g fuel) from a few percent at the lowest HF and up to ten percent at the highest HF. During combustion in air, equivalent black carbon (eBC) emissions were found to moderately increase with increasing HF. eBC was also found to increase when the O2 availability or combustion was reduced (O2 deficient combustion). Polycyclic aromatic hydrocarbon (PAH) was here defined separately from OA in the AMS analysis. PAH emissions were low for pyrolysis and combustion at high air flows (excessive O2 availability). In contrast, O2 deficient combustion conditions resulted in dramatically increased PAH emissions, with yields as high as to 0.5% (g/g fuel). The relationship between PAH emissions and availability of air and O2 during combustion is illustrated in Figure 1.
Future analyses include a more detailed PAH analysis including off-line GC-MS, thermal-optical carbon analysis, UV-VIS absorption of MeOH soluble OA. We will parameterize emissions based on the initial conditions such as HF, moisture content, air flow rate (cooling) and O2 availability. A mechanistic understanding of relationships between combustion variables and emissions can aid the development of cleaner biomass combustion technologies and will improve fire emission models.
- LTH Profile Area: Aerosols
- NanoLund: Center for Nanoscience
- Ergonomics and Aerosol Technology
- Division of Fire Safety Engineering
- LTH Profile Area: Energy Transition – Power and Transport
- LTH Profile Area: Circular Building Sector
- LTH Profile Area: Nanoscience and Semiconductor Technology
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Conference paper: abstract
- Chemical Process Engineering
- Energy Engineering
- Cone calorimeter
- Fire Aerosols
- biomass combustion
International Aerosol Conference 2022
2022-09-04 - 2022-09-09