I. Core Working Principle

1. Flue Gas Introduction and Uniform Distribution

2. High-voltage Ionization and Particle Charging

3. Electrostatic Adsorption and Collection

4. Water Film Ash Cleaning and Gas Discharge

II. Typical Technological Process

1. Process Positioning

2. Complete Process Flow

3. Key Process Design

• Pre-treatment Adaptation: The flue gas at the desulfurization tower outlet passes through a demister to remove large-size fog droplets (concentration ≤50mg/m³), avoiding electrode scaling caused by excessive slurry droplets entering the WESP.

• Electric Field Configuration: 2-4 electric fields are connected in series with a single electric field voltage of 60-80kV, ensuring sufficient charging and adsorption of fine particles with a total purification efficiency ≥99.9%.

• Spray System: Fan-shaped atomizing nozzles are adopted with spray pressure of 0.3-0.5MPa to achieve full coverage of anode plates. The water conductivity shall be ≤1000μS/cm to avoid affecting electric field stability.

• Wastewater Treatment: WESP wastewater is combined with desulfurization wastewater. After neutralization, flocculation and sedimentation treatment, the wastewater is reused or discharged up to standard (pH controlled at 6-9).

III. Core Process Advantages and Adaptability

• Strong Pertinence: Specially designed for escaped pollutants such as PM2.5, acid mist and heavy metals in flue gas after desulfurization and denitrification, completely eliminating white smoke plume phenomenon.

• No Secondary Dust Re-entrainment: Water film ash cleaning replaces dry rapping to prevent dust from falling back into flue gas, ensuring stable purification performance.

• Corrosion Resistance: Anode plates/tubes are made of corrosion-resistant materials such as 316L stainless steel and FRP, adapting to acidic wet flue gas with equipment service life ≥15 years.

Key Process Parameters of Wet Electrostatic Precipitator

I. Core Electric Field Parameters (Determine Electrostatic Adsorption Effect)

• Working Voltage: Conventional range 60-100kV; single electric field voltage 60-80kV (2-4 electric fields in series). The voltage fluctuation shall be controlled within ±5% of the designed value. Excessively low voltage causes insufficient ionization, while excessively high voltage leads to breakdown discharge.

• Working Current: Calculated by plate area with current density of 0.1-0.3mA/m². The total current shall match the gas treatment capacity to avoid insufficient adsorption force caused by low current and electric field short circuit caused by excessive current.

• Electrode Spacing: Homopolar spacing 250-400mm (commonly 300mm) with deviation ≤±5mm. Uneven spacing causes electric field distortion and reduces charging efficiency.

• Electric Field Wind Velocity: ≤3.5m/s for plate-type WESP and ≤3.0m/s for tubular/honeycomb WESP. Excessively high wind velocity shortens particle residence time, while low velocity increases equipment volume. Both efficiency and economy shall be balanced.

II. Flue Gas Working Condition Parameters (Key Adaptability Indicators)

• Inlet Flue Gas Temperature: Optimal range 40-60℃, maximum ≤80℃. Excessively high temperature reduces gas breakdown voltage, while low temperature causes water film icing and condensation corrosion.

• Inlet Flue Gas Humidity: ≥90% (saturated wet flue gas). Water supplementation is required if humidity is insufficient to guarantee dust charging and water film formation.

• Inlet Pollutant Concentration: Particulate matter ≤30mg/m³, fog droplets ≤50mg/m³. Pre-demister or pre-duster is required for excessive concentration to prevent electrode scaling and blockage.

• Flue Gas Dust Characteristics: For fine pollutants such as PM2.5, acid mist (SO₃) and heavy metals, sufficient particle charging shall be ensured, and electric field stages shall be adjusted if necessary.

III. Spray Ash Cleaning System Parameters (Ensure Pollutant Desorption Efficiency)

• Spray Pressure: 0.3-0.5MPa. Insufficient pressure fails to form a uniform water film, while excessive pressure causes fog droplets to be carried away by flue gas and increases outlet droplet concentration.

• Spray Water Volume: Calculated by plate area at 1-2L/(m²·min). Full coverage of anode plates is required to form a continuous water film and avoid scaling in local dry areas.

• Spray Water Quality: Conductivity ≤1000μS/cm, pH 6-9, suspended solids ≤50mg/L. Poor water quality leads to electrode scaling and nozzle blockage, affecting electric field stability.

• Spray Cycle: Continuous spraying for high-viscosity pollutants; intermittent spraying for conventional working conditions (cycle: 1-4h). The interval shall be controlled to prevent excessive pollutant adhesion.

IV. Equipment Structure and Performance Parameters

• Electric Field Stages: 2-4 stages connected in series. Single-stage efficiency ≥95% and total efficiency ≥99.9%. More stages provide better purification effect; 3-4 stages are required for strict emission standards (such as ≤5mg/m³).

• Plate Material and Type: Anode plates adopt corrosion-resistant materials including 316L stainless steel and FRP. Plate-type structure covers large floor area, while honeycomb type features uniform electric field and small floor area, adapting to acidic wet flue gas.

• Equipment Resistance: Operating resistance ≤300Pa, maximum ≤500Pa. Excessively high resistance increases fan energy consumption, which shall be controlled by airflow optimization design.

• Air Leakage Rate: ≤2%. Air leakage dilutes flue gas concentration, reduces flow velocity stability, and introduces cold air to cause condensation corrosion.

V. Safety and Operation Control Parameters

• Grounding Resistance: ≤4Ω to ensure reliable grounding of high-voltage system and avoid electric shock risks.

• Insulation Resistance: Insulator insulation resistance ≥100MΩ to prevent electric leakage and electric field short circuit caused by insulation failure.

• Equipment Pressure Resistance: Shell design pressure ±5kPa to bear flue gas pressure fluctuation and prevent deformation and leakage.