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Abstract
Combustion aerosols were measured in a 22 MW (thermal energy) municipal waste incinerator. Different types of waste fractions were added to a base-load waste and the effect on aerosol formation was measured. The waste fractions applied were: PVC plastic, pressure-impregnated wood, shoes, salt (NaCl), batteries, and automotive shredder waste. Also, runs with different changes in the operational conditions of the incinerator were made. Mass-based particle size distributions were measured using a cascade impactor and the number-based size distributions were measured using a Scanning Mobility Particle Sizer. The plant is equipped with flue gas cleaning and the penetration through this was determined. The particle morphology was investigated by Transmission Electron Microscopy (TEM) and chemical analysis of the aerosol particles was made by Energy Dispersive X-ray Spectroscopy (EDS). The mass-based particle size distribution was bimodal with a fine mode peak around 0.4 µm and a coarse mode peak around 100 µm. The addition of NaCl, shredder waste, and impregnated wood increased the mass concentration of fine particles (aerodynamic diameter below 2.5 µm). In general the mass concentration was stable and close to the reference PM2.5-value of 252 ± 21 mg/m3 (std.T,P). The total number concentration deviated during runs and between runs spanning from 43 · 106 to 87 · 106 #/cm3(std.T,P). The aerosols formed were mixtures of dense and aggregated particles in all tests. The fine particles are mainly composed by alkali salts, zinc, and lead. The heavy metals Cu, Cd, Hg, and Pb are significantly enriched in the fine particles.
This work was carried out under PSO-contract no. 5784, financed by I/S Vestforbrænding, DONG Energy A/S, Aarhus Kommunale Værker, Babcock Vilcox V⊘lund A/S, and Energinet.dk. The work was carried out in collaboration between the Combustion and Harmful Emission Control (CHEC) Research Centre, and Institute of Environment and Resources at the Technical University of Denmark. The CHEC Research Centre is co-funded by Dong Energy, the Danish Energy Research Programme, Nordic Energy Research, and the European Union. We specifically want to thank the people from I/S FASAN Waste Incineration Plant for participating in the campaign.
Notes
∗organically bound.
∗∗inorganically bound.
The estimate of the chemical composition is based on previous analysis of Dansih household waste and small combustibles (Riber and Christensen, Citation2006). The X-marks indicate which elements are expected to be increased when the fuel is mixed with the special waste fractions.
The temperatures in the bottom and the top of the combustion chamber and the temperature at the sampling point are given. The gas flows of primary, secondary, and total air are given on a normalized basis (to the average values).
∗Average of three average values for the three days with reference runs. The standard deviations for these data reflect the deviation between the different reference runs. All other standard deviations reflect the deviation during a single run.
The data are based on measurements from two reference runs. The fly ash is analyzed for the relevant elements by ICP-OES. The EDS measurements are normalized to the elemental content without oxygen, since oxygen is not detectable. To enable comparison, this is corrected for in the ICP-OES data. The standard deviation shown for the total dust is based on multiple measurements of the two samples. The standard deviation shown for the PM2.5 particles is between deposits from different impactor stages in a single series.
