Droplet charging for wet scrubbers

Area of Science:

• Environmental Engineering
• Electrostatics
• Fluid Dynamics

Background:

• Wet scrubbers are essential for industrial air pollution control.
• Droplet charging is a key parameter influencing scrubber efficiency.
• Understanding droplet charge-to-mass ratio is vital for optimizing scrubber performance.

Purpose of the Study:

• To quantify the charge-to-mass ratio of water droplets in a wet scrubber system.
• To investigate the influence of applied voltage, water pressure, and nozzle type on droplet charging.
• To establish relationships between operational parameters and droplet electrostatic properties.

Main Methods:

• Water droplet charge-to-mass ratio was measured under varying direct charging potentials (0-20 kV).
• Experiments were conducted using spiral, impingement, and whirl spray nozzles.
• Water pressure was controlled within the range of 30-70 psig (206.8-482.6 kPa).

Main Results:

• The measured charge-to-mass ratio ranged from -0.0005 to 0.2 microcoulombs/gram.
• A direct correlation was observed between the applied voltage and the water droplet charge-to-mass ratio.
• Nozzle design significantly impacted charge-to-mass; smaller orifice, lower-flow nozzles yielded higher ratios.

Conclusions:

• Applied voltage is a primary driver for water droplet charging in wet scrubbers.
• Nozzle characteristics, specifically orifice size and flow rate, are critical factors in achieving higher droplet charge.
• Optimizing nozzle selection and applied voltage can enhance the efficiency of electrostatic wet scrubbers for particulate removal.