PSI - Issue 77

Alexander Backa et al. / Procedia Structural Integrity 77 (2026) 143–151 A. Backa et al. / Structural Integrity Procedia 00 (2026) 000 – 000

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Fig. 3. Underfed pellet burner and the selected measurement planes for PM particles and temperature in a specific region.

3. Results and discussion A average values of the results is presented in Table 2. There was a noticeable variation in PM levels among different planes and quarters, with some areas exhibiting higher concentrations than others. The average PM concentration across all quarters was 19.99 mg/m 3 and the average temperature was 537 °C. XY Plane: The average PM concentration on the XY plane was 21.33 ± 9.53 mg/m 3 , with an average temperature of 472 °C. The highest average PM concentration, 23.45 ± 9.14 mg/m 3 , was observed in quadrant XY3 at an average temperature of 429 °C. The temperature-to-PM ratios within the XY plane suggest that quadrant XY1, with a ratio of 22.15, shows a higher temperature effect per unit of PM, while XY3 exhibits a lower temperature influence per unit PM concentration at 18.30. This indicates a relative variability in combustion efficiency or distribution of PM across the XY plane. YZ Plane: On the YZ plane, the average PM concentration was slightly lower at 20.78 ± 25.69 mg/m 3 , but the average temperature was higher at 599 °C. Quadrant YZ3 showed the highest average temperature in the entire measurement set, reaching 785 °C, and also had the highest average PM concentration when considering all measured values at 26.09 ± 43.22 mg/m 3 . The YZ1 quadrant, with a temperature-to-PM ratio of 35.94, shows the highest temperature relative to PM concentration on the plane. XZ Plane: The XZ plane had the lowest average PM concentration at 17.85 ± 10.40 mg/m 3 , with a mean temperature of 539 °C. The highest temperature-to-PM ratio was observed in quadrant XZ4, reaching 40.76, indicating an efficient combustion process with low PM output relative to temperature. Overall Averages: Across all quadrants, the average PM concentration was 19.99 ± 16.76 mg/m 3 , with an average temperature of 537 °C. The average temperature-to-PM ratio was 26.85, while the PM-to-temperature ratio was 0.0372. The standard error values indicate variability in combustion conditions across the sampled zones. Particulate matter generation exhibits significant variability, directly influenced by fuel combustion parameters and the consistency of thermal conditions inside the combustion chamber, as noted by Jandačka et al. (2008) . Therefore, precise control over these factors is essential for minimizing PM emissions. Shen et al. (2012) identified key factors affecting PM emissions in biomass combustion, with temperature playing a crucial role. Higher temperatures modified PM size distribution and improved combustion, thereby lowering emissions.