Particulate matter (PM) emissions from biomass combustion present a significant challenge to the integration of bioenergy into the sustainable energy landscape. The BioPM project adopts a comprehensive approach, addressing PM emissions from wood combustion through three key angles:
1. Experimental evaluation of PM mitigation strategies
Various measurement campaigns were conducted to characterize PM emissions from various wood boilers, including:
- 18 kW condensing wood pellet boiler
- 40 kW laboratory wood pellet boiler
- 240 kW wood chip boiler with an integrated electrostatic precipitator (ESP)
- Two medium-scale (~5 MW) wood chip boilers equipped with multi-cyclone, baghouse filters and flue gas condenser
These measurements provided valuable insights into the operation and effectiveness of the PM mitigation technologies, such as flue gas condensers[1], ESP[2] and baghouse filters[1, 3].
2. Measurement setup evaluation
The measurement setup underwent thorough evaluation to ensure the unambiguous quantification of PM emissions based on the particle number size distribution. The measurement setup featured a Dekati Electrical Low Pressure Impactor (ELPI+) alongside various dilution systems. It was found that the ELPI+ measurement results tend to drift off over time with specific collection surfaces[4]. In addition, by examining the data inversion algorithm of ELPI+ (i.e. the process to convert measured electrical currents into particle number size distributions), a theoretical explanation was derived for the sporadic detection of unusually high concentrations of small particles by ELPI+[5]. Furthermore, the impact of the dilution setup and the dilution conditions on the PM measurements was also assessed[6].
3. Numerical framework development
A numerical flue gas dynamics framework was developed to complement the experimental findings. This 1D-model describes the behavior of gases and particles flowing through a straight duct by solving conservation laws and the general dynamic equation for aerosols. The framework incorporates various phenomena, including particle deposition (due to Brownian diffusion, turbulent inertial impaction, thermophoresis and diffusiophoresis), gas-particle interactions (e.g. condensation growth) and thermal coagulation. The model has provided valuable insights into the significance of coagulation in flue gas condensers and dilution systems.
This project was the doctoral research of Jordi Cornette, leading to his degree of Doctor of Engineering Technology in July 2022, under the supervision of Professor Svend Bram.
Related publications
[1] Cornette, Coppieters, Lepaumier, Blondeau & Bram (2021) Biomass and Bioenergy 148:106056. doi: 10.1016/j.biombioe.2021.106056
[2] Cornette, Dyakov, Plissart, Bram & Blondeau (2024) Journal of Electrostatics 128:103897. doi: 10.1016/j.elstat.2024.103897
[3] Cornette, Coppieters, Desagher, Annendijck, Lepaumier, Faniel, Dyakov, Blondeau & Bram (2020) Aerosol and Air Quality Research 20(3):499-519. doi: 10.4209/aaqr.2019.10.0487
[4] Cornette, Blondeau & Bram (2023) Powder Technology 419:118333. doi: 10.1016/j.powtec.2023.118333
[5] Cornette & Bram (2023) Aerosol Science and Technology 57(2):175-185. doi: 10.1080/02786826.2022.2156319
[6] Cornette, Dyakov, Blondeau & Bram (2023) Environmental Research 236(1):116714. doi: 10.1016/j.envres.2023.116714