Influence of mineral transformation on emission of particulate matters during coal combustion

Abstract

Combustion of pulverized coal was studied in a drop tube furnace to understand coal mineral properties with the emission of particulate matters (PM). Experimental conditions were selected as follows: coal particle size was smaller than 63 µm; reaction temperature was 1 100°C, 1 250°C and 1 400°C respectively; oxygen content was 20% and 50% respectively. PM was collected with a 13-stagelow pressure impactor (LPI) having an aerodynamic cut-off diameter ranging from 10.0 µm to 0.03 µm for a size-segregated collection. Such properties as concentration, particle size distribution and elemental composition of PM were investigated. The experimental results indicate that the emitted PM has a bimodal distribution having two peaks around 4.0 µm and 0.1 µm. Increasing temperature leads to the formation of more PM; varied oxygen content leads to much change of emitted PM. PM was also subjected to XRF analysis to quantify the elemental composition. The results show that PM of 0.1 µm is rich in sulfates. Meanwhile, SiO 2 and Al 2 O 3 are prevalent in PM of 4.0 µm, which means that the last peak around 4.0 µm is mainly aluminosilicate salts.

Atmospheric iron deposition in the northwestern Pacific Ocean and its adjacent marginal seas: The importance of coal burning

“…Mass fractions of Fe and Al in various types of dust and soil particles, coal, and combustion ashes. Red circles and black dots enclosed by red circle represent typical fly ash [ Yuan et al ., ; Liu et al ., ; Koukouzas et al ., ; Liu et al ., ; Cao et al ., ; Wang et al ., ; Vassilev and Vassileva , ; Zhang et al ., ; Tang et al ., ; Zhang et al ., ] and bottom ash [ Liu et al ., ; Wang et al ., ], respectively; red dots represent fly ash from steel plant [ Prati et al ., ; Geagea et al ., ; Tsai et al ., ]; green dots with red circles represent fly ash from biomass burning [ Gaudichet et al ., ; Yamasoe et al ., ]; black squares represents coal [ Querol et al ., ; Liu et al ., ; Zhang et al ., ; Dai et al ., , ; Dai et al ., , ; Yang , ; Song et al ., ; Wang et al ., ; Yang , ; Sun et al ., ; Zhou et al ., ; Li et al ., ]; orange, blue, green and purple diamonds represent desert dust [ Li et al, ; Ishizaka , ; Tian et al ., ; Mori et al ., ; Zhang et al ., ], river dust [ Li et al ., ; Tan et al ., ; Lin , ], agriculture and topsoil dust [ Su et al ., ; Li et al ., ; Yanai et al ., ], and urban dust [ Dong et al ., ], respectively. The blue‐shaded area represents the range (i.e., 1.3 to 2.7) of Fe to Al ratios in particles collected in seawater from the SEATS 2007 observations [ Ho et al, ].…”

Could the Rebound Characteristics of Oblique Impact for SiO2 Particles Represent the Ash Particles?

“…For different types of coal, the ash content varies. The predominant component in the ash is always SiO 2 . , Therefore, the SiO 2 and ash particles with diameters of 25 μm are selected. The morphology of the SiO 2 particle is obtained by SEM, as shown in Figure .…”