Fine particle migration and collection in a wet electrostatic precipitator

Area of Science:

• Environmental Engineering
• Chemical Engineering
• Atmospheric Science

Background:

• Electrostatic precipitation is a key technology for fine particle removal.
• Wet electrostatic precipitators (WESP) offer potential advantages over dry systems.
• Understanding particle migration and collection in WESP is crucial for optimizing air pollution control.

Purpose of the Study:

• To investigate the performance of a lab-scale wet electrostatic precipitator (ESP) for fine particle removal.
• To compare the particle removal efficiency and corona discharge characteristics of wet ESP with dry ESP.
• To evaluate the influence of various parameters on WESP performance, including electrode type, SO2 concentration, specific collection area (SCA), and droplet interaction.

Main Methods:

• Development and testing of a lab-scale wet ESP with a wire-to-plate configuration.
• Evaluation of corona discharge characteristics.
• Measurement of total and fractional particle removal efficiency.
• Systematic variation of operational parameters: discharge electrode type, SO2 concentration, SCA, and particle/droplet concentration.

Main Results:

• Wet ESP achieved a higher total particle removal efficiency (97.86%) compared to dry ESP (93.75%).
• Fishbone electrodes yielded higher efficiency and migration velocity than other types.
• Increased SO2 concentration (0-43 ppm) reduced removal efficiency by 2.87% due to suppressed corona discharge and particle charging.
• Removal efficiency increased with SCA, though marginally (0.71%) between 25.0 and 32.5 m²/(m³/s).
• Higher particle and droplet concentrations promoted particle aggregation, enhancing removal efficiency.

Conclusions:

• Wet ESP is a highly effective technology for fine particle removal, outperforming dry ESP.
• Optimizing discharge electrode design, managing SO2 levels, and controlling droplet concentrations are critical for maximizing WESP efficiency.
• The study provides a basis for the design and application of wet ESP systems in air pollution control.