Capture of submicrometer particles in a pressurized electrostatic precipitator

Figures & data

Figure 1. Schematic of the experimental setup.

Table 1. Summary of performed studies.

Set	Objective	Particles	Gas compositions	ESP operation	Gas pressure	Flow rate	Measurements
I	To investigate the I-V characteristics of the ESP	N/A	Air; simulated flue gas (6% O2, 12% CO2, 82% N2)	−20 kV to +20 kV	1, 2, and 3 atm	15 LPM	ESP current
II	To investigate the capture efficiency of NaCl particles	NaCl particles	Air; simulated flue gas (6% O2, 12% CO2, 82% N2)	Current controlled (±20 μA); voltage controlled (+12.8 ∼ +19.8 kV; −12.3 ∼ −16.9 kV)	1, 2, and 3 atm	15 LPM	Particle size distributions downstream of the ESP when the ESP is off and on
III	To investigate the capture efficiency of fly ash particles	Fly ash particles from drop-tube furnace	Exhaust gas from the drop-tube furnace system	−20 μA	1, 2, and 3 atm	25 LPM	Particle size distributions downstream of the ESP when the ESP is off and on
IV	To develop a semiempirical model	NaCl particles	Air	−20 μA	1.5 and 2.5 atm	15 LPM	Particle size distributions downstream of the ESP when the ESP is off and on

Figure 2. The influences of gas pressure on (a) I-V characteristics and (b) corona onset voltage with different gas compositions (air and SFG). (a) I-V curves of the ESP under three pressure conditions (1, 2, and 3 atm) with air and SFG as the feed gas, respectively; (b) the relationship between the corona onset voltage and gas pressure (experimental results for air and SFG, estimation for air case based on Equation (2[2] ), and fitting curve for SFG case; “pos”: short for “positive”; “neg”: short for “negative”).

Figure 3. Experimental and calculated I-V curves by Equations (5[5] ) and (6[6] ) under different pressures.

Figure 4. NaCl particle penetrations through the ESP using air as feed gas under different gas pressures: (a) negative ESP, voltage controlled; (b) positive ESP, voltage controlled; (c) negative ESP, current controlled; (d) positive ESP, current controlled.

Figure 5. NaCl particle penetrations through the ESP using SFG as feed gas under different gas pressures: (a) negative ESP, voltage controlled; (b) positive ESP, voltage controlled; (c) negative ESP, current controlled; (d) positive ESP, current controlled.

Figure 6. Particle penetrations through the ESP for fly ash particles of various sizes under different gas pressures.

Figure 7. Calculating procedure of capture efficiency in pressurized ESPs using Equation (20[19] ) as the modified expression for the number of elementary charges of the particles.

Figure 8. Particle penetrations for various particle sizes measured under 1, 2, and 3 atm and the corresponding calculated values using Equation (20[19] ) (summation of squared deviations [σ'] is 0.0022, which excludes the case of “1 atm and 20 µA”).

Figure 9. Particle penetrations for various particle sizes measured under 1.5 and 2.5 atm and the corresponding calculated values using Equation (20[19] ).