Size Distribution Evolution of Fine Aerosols Due to Intercoagulation with Coarse Aerosols

Figures & data

Figure 1 centering Various types of coagulation for bimodally distributed particles.

Table 1 Simulation conditions for studying the effects of intercoagulation on fine mode particle removal

	d gf d gc (μ m)	σ gf σ gc	N f0 (#/cc)	N c0 (#/cc)
Set I	0.01 10	1.3 1.3	10^4–10^15	10^6–10^12
Set II	0.01 10	1.0–1.6 1.0–3.0	10^8	10^8
Set III	0.01–0.5 1–500	1.3 1.3	10^8	10^8
Set IV	0.01 1–100	1.3 1.0–3.0	10^6	10^4–10^13
^*All simulations conducted for T = 740 °C.

Figure 2 Fine-mode removal time as a function of fine-mode number concentration for various coarse mode number concentrations. The solid line connects points where N _f0/N _c0 = 10.

Figure 3 centering Dimensionless removal time as a function of (a) normalized number concentration and (b) normalized mass or volume concentration.

Figure 4 centering Evolution of fine-mode (σ _gf0 = 1.4) and coarse-mode (σ _gc0 = 1.3) particle size distributions by intercoagulation to reach removal time (t _r = 0.106 s).

Figure 5 Dimensionless removal time as a function of (a) fine-mode geometric standard deviation, where σ _gc0 = 1.3, and (b) coarse-mode geometric standard deviation, where σ _gf0 = 1.3.

Figure 6 (a) Dimensionless removal time and removal time as a function of d _gc /d _gf . (b) Dimensionless removal time as a function of fine-mode mean size.

Figure 7 (a) Removal time as a function of coarse-mode standard deviation and d _gc /d _gf with the same number concentration (10¹⁰/cm³) and (b) the same mass concentration (10 μ g/cm³).

Table 2 Size distribution parameters and removal time for Linak et al. (2003)

	d gf d gc (μ m)	σ gf σ gc	N f0 (#/cc)	N c0 (#/cc)	t r (s)	t 1/2 (s)
Case I	0.01 1.4	1 1	4.72 × 10^10	1.80 × 10^5	8.1 × 10^85	8.6 × 10^34
Case II	0.07 1.4	1 1	1.38 × 10^8	1.80 × 10^5	2,094	263
Case III	0.01 1.4	1 1	4.72 × 10^10	1.80 × 10^7	2.65	0.12

Table 3 Operating parameters of a FGD system and particle size distribution from a power plant

	FGD system (Harries 1993)	Particulate matter (Bacci et al. 1983)
Operating conditions	Diameter: 1.25 m	N/A
	L/G: 0.015 m^3/Nm^3
	Gas flow: 2000 Nm^3/h
	Slurry flow: 30 m^3/h
Particle size distribution	Actual	m f0: 18.7 mg/m^3
	m c0: 17.4 × 10^6 mg/m^3	MMD: 0.01 μ m (assumed)
	Droplet size > 500 μ m	σ gf : 1.3 (assumed)
	σ gc : 1 (assumed)	N f0: 7.8 × 10^9 #/cm^3 (calculated)
	N c0: 2.3 × 10^2 #/cm^3 (calculated)
	Desired
	Droplet size : 10 μ m
	σ gc : 1.3 (assumed)
	N c0: 2.1 × 10^7 #/cm^3 (calculated)

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