Behavior of Alkali Metal Aerosol in a High-Temperature Porous Tube Sampling Probe

Figures & data

FIG. 1 The experimental setup.

FIG. 2 Scheme of supply system for (a) aerosol precursors, (b) seed particle generation, and (c) aerosol sampling.

TABLE 1 Reactor and sampling conditions, particle concentrations, and particle size modes

	KCl	H2O	SO2	Sulfation	KCl in
	supply	supply	supply	efficiency^b	sample	Sampling	Primary	N-SMPS	Mode 1	Mode 2
Case	(mg/m^3)^a	(vol%)	(mg/m^3)^a	(%)	(mg/m^3)^a,c	position	DR	(1/cm^3)^d	(nm)	(nm)
1	196	0.6	—	—	196	B	53	2.74E+10	6.6	—
2	189	0.6	610	62.2	71	A	17	5.50E+09	5.1	32.2
3	192	0.6	610	61.8	73	B	17	4.78E+09	5.1	37.2
4	197	0.6	610	66.8	65	C	17	9.17E+09	8.5	33.4
5	203	0.6	610	65.1	71	D	17	2.74E+10	6.6	33.4
6	191	0.6	610	66.8	63	B	18	5.89E+09	5.1	23.3
7	192	0.6	610	64.0	69	B	91	8.45E+08	3.3	24.1
8	190	0.6	610	64.9	67	B	7	3.24E+09	6.4	26.9
9	189	0.6	610	64.6	67	B	4	1.80E+09	8.5	30.0
10	185	0.7	610	64.3	66	B	2	9.78E+08	9.5	31.1
11	186	0.6	610	64.4	66	B	15	4.77E+09	5.3	23.3
12	169	0.6	610	61.3	65	B	20	3.53E+09	4.6	23.3
13	179	0.6	213	50.1	89	B	20	6.80E+09	5.1	25.9
14	184	0.6	916	63.2	68	B	21	2.32E+09	4.0	22.5
15	185	0.6	1220	67.8	60	B	21	1.39E+09	4.1	21.7
16	181	6.0	1220	86.0	25	B	40	2.47E+09	—	28.9
^aConcentrations are given in standard temperature and pressure (20°C, 101325 Pa) on dry basis.
^bCalculated conversion of KCl to K2SO4 based on HCl gas concentrations measured from the reactor.
^cEstimated KCl concentration in the sample based on HCl gas concentrations measured from the reactor.
^dConcentrations are dilution corrected and given in standard temperature and pressure (20°C, 101325 Pa) on dry basis.
Bold entries indicate the variable parameters during the experiments.

FIG. 3 TEM micrograph of K₂SO₄ particles from conditions corresponding to case 12 in Table 1.

FIG. 4 Measured temperature and mixing profiles of sample in the diluter with a DR of 20 and sampling position B. The values represent conditions in the radial centerline of the tube.

FIG. 5 Sample temperature profiles in the sampling system with two measured and two fictive cases. The values represent conditions in the radial centerline of the tube.

FIG. 6 Sample cooling rates in the diluter given as cumulative distribution (i.e., each value is the average cooling rate from the sample inlet to the corresponding point).

FIG. 7 Particle size distributions with (a) various K₂SO₄/KCl ratios, (b) various primary DRs, (c) various sampling locations, and (d) comparison of simulated and measured particle size distributions. The number concentrations are dilution-corrected.

TABLE 2 Calculated cases of aerosol dynamics in the diluting probe, the mass fractions of KCl in the nucleation mode (PM0.01), and particle size distribution modes after the sampling line

					KCl in
	KCl	K2SO4	Temperature		PM0.01	Mode 1	Mode 2
Simulation	(mg/m^3)^a	(mg/m^3)^a	profile	DR	(m%)	(nm)	(nm)
1	89	0	Measured	20	100	6.5	—
2	89	0	Measured	85	100	3.3	—
3	89	10.5	Measured	20	73	6.1	32
4	89	10.5	Measured	85	75	3.3	28
5^b	89	105	Measured	20	6.2	3.3	30
6	89	105	Measured	85	21	2.7	26
7	89	105	Probe cooling	20	0.94	1.8	30
8	89	105	Efficient cooling	20	4.1	3.3	30
^aConcentrations are given in standard temperature and pressure (20°C, 101325 Pa) on dry basis.
^bSimulation of the measurement case 13.
Mode 1 = Number concentration mode of particles formed by homogeneous nucleation.
Mode 2 = Number concentration mode of seed particles.

FIG. 8 Simulated aerosol dynamics in the probe, simulation 5.

FIG. 9 The mass size distributions of condensed KCl inside the diluter. (Color figure available online.)