Wet Electrostatic Precipitator

Wet Electrostatic Precipitator(WESP for short)is an advanced dust removal device that uses a high-voltage electric field to charge dust particles and then captures the charged dust with sprayed water mist.Its core function is to remove pollutants that are difficult to eliminate by traditional dry dust removal methods,such as ultrafine dust(particle size<1μm),acid mist,and gypsum rain.It can control the outlet dust concentration below 5mg/m³,and even achieve ultra-clean emission standards of 1mg/m³.Widely used in industrial fields requiring ultra-low emissions,such as thermal power plants,iron and steel industry,waste incineration,and chemical industry,WESP is a key terminal equipment for realizing"ultra-clean emission"of flue gas.

Its working principle is based on the dual mechanism of"electrostatic adsorption+wet collection":The main body of the equipment is a closed shell,inside which there are cathode wires(releasing high-voltage electricity to generate a corona electric field)and anode plates(collecting charged dust).When the dust-containing flue gas enters the shell,dust particles and acid mist droplets are ionized and charged under the action of a high-voltage electric field(usually 30-60kV).The charged particles move towards the anode plates under the influence of electric field force and adhere to the surface of the anode plates.At the same time,the spray system sprays high-pressure water mist onto the anode plates,forming a water film that washes the dust on the plates into the liquid collection tank at the bottom,which is then discharged with wastewater.The purified flue gas passes through a demister to remove water mist before being discharged up to standard.

The structural design focuses on"efficient collection and corrosion prevention":First,electric field structure-the cathode wires mostly adopt needle wires(to enhance the corona effect),and the anode plates are usually flat or honeycomb-shaped(honeycomb type occupies less space and has higher collection efficiency).The distance between the plates is controlled at 150-300mm to ensure a uniform electric field.Second,spray system-corrosion-resistant atomizing nozzles(such as PTFE material)are used,with a spray pressure of 0.3-0.5MPa,to ensure a uniform water film is formed on the plates and prevent dust accumulation.Third,anti-corrosion treatment-parts in contact with corrosive media,such as the shell,anode plates,and pipelines,are made of FRP(Fiberglass Reinforced Plastic),316L stainless steel,or rubber-lined materials to prevent corrosion by acid mist(such as SO₃and HCl)and extend the service life of the equipment.

The core advantages are reflected in three aspects:First,extremely high dust removal accuracy-the removal efficiency of ultrafine dust,PM2.5,and acid mist is≥90%,which can stably control the outlet dust concentration below 5mg/m³and meet the national ultra-low emission requirements.Second,adaptability to complex flue gas-it is not affected by dust specific resistance or humidity,and can handle flue gas with high humidity(moisture content>20%),high viscosity(such as gypsum slurry droplets),and corrosive media,making up for the shortcomings of dry electrostatic precipitators and bag filters.Third,no secondary dust emission-dust is collected by water film washing,avoiding secondary dust emission during the ash cleaning process of dry dust removal.At the same time,it can synergistically remove some heavy metals(such as mercury)and dioxins.

Typical application scenarios include:Thermal power plants(deep dust removal of flue gas after desulfurization in coal-fired units to remove gypsum rain and ultrafine dust);Iron and steel industry(ultra-low emission control of flue gas from sintering machines and pelletizing plants,with synergistic removal of acid mist);Waste incineration(terminal flue gas purification to deeply remove dust and heavy metals);Chemical industry(dust removal of tail gas from sulfuric acid production and coal chemical industry,with resistance to corrosive flue gas).Currently,WESP is being optimized through modular design(reducing floor space)and intelligent operation and maintenance(installing dust concentration and corrosion monitoring sensors)to further improve operational stability and economy.