Wet electrostatic precipitators

Wet electrostatic separation

Wet electrostatic separation: basic principle and description of the process

Injecting recirculating water causes the crude gas to cool to its saturation point inside the crude gas duct. The quenched crude gas then enters the filter, where it is uniformly distributed across the entire filter cross-section. In the downstream gas scrubber, dust-type and gaseous organic compounds are separated.

The pre-cleaned gas now flows into the wet electrostatic precipitator. This consists of a high-voltage field with collecting electrodes and centrally located ionising electrodes. The particles and aerosols still present in the gas become negatively charged and move through the electrical field to the collecting surface. Periodic rinsing ensures that the collecting surfaces and ionising electrodes remain clean.

The rinse water remains in a closed loop system that includes an internal water processing unit. Sedimentation of solids in the water is made possible by special, built-in patented sedimentation surfaces in the water collection container. This sedimentation sludge is removed via a discharge screw and a downstream dewatering unit. The use of additives ensures a consistently high water quality.

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WET ELECTROSTATIC PRECIPITATORS seka – Condensation wet electrostatic precipitator for dryer exhaust gas purification

WET ELECTROSTATIC PRECIPITATORS

In recent years, wet electrostatic precipitators have won particular recognition as a method for cleaning exhaust gases from dryers used in the wood based panel industry (for MDF, chipboard and pellets and OSB). As well as offering outstanding dust and aerosol separation, systems of this kind also enable efficient reduction of odour emissions. A wet electrostatic precipitators is a combination of a wet scrubber and an electrostatic precipitator. seka and sena are based on wet electrostatic precipitators, but Scheuch has revised the concept underpinning them and adapted it specifically to suit this application. SENA – WET ELECTROSTATIC PRECIPITATOR FOR DRYER EXHAUST GAS PURIFICATION

The sena process involves a single-stage wet electrostatic precipitator for dust and aerosol separation, featuring honeycomb precipitation surfaces. The system is ideal for use in the wood based panel industry (chipboard, OSB and MDF board production), the plywood and insulating material industry, and the pellet industry. If required, specific levels of additives (oxidants) can also be incorporated in order to separate organic substances, particularly formaldehyde.

Benefits

Excellent separation performance
i.e. excellent separation of dust and aerosols (blue haze) as well as organic substances

Low operating costs
thanks to low system pressure losses and low maintenance expenditure.

Excellent availability
thanks to a recirculating water treatment system that has been specifically optimised for the wood based panel industry, as proven testing multiple times in practice. To keep the system operating reliably over the long term, it is extremely important that all the spray systems function correctly at all times. Additionally, the recirculating water has to reach a level of quality that makes it suitable for the cleaning function, as the caking that results from insufficient cleaning is critical to operational safety. If the spray systems fail and these coatings dry out as a result, this presents a significant issue as the coatings cannot be cleaned with normal water and pose a latent risk of fire.

Heat recovery
with the option of putting residual heat from the water circuit to good use in other processes

seka – Condensation wet electrostatic precipitator for dryer exhaust gas purification

The SEKA process involves a two-stage wet electrostatic precipitator for dust separation, featuring tubular precipitation surfaces. As well offering the benefit of condensation, this system also contains the option of removing the exhaust gas plume by mixing in preheated cooling air. If required, specific levels of additives (oxidants) can also be incorporated in order to separate organic substances, particularly formaldehyde.

Benefits

Excellent separation performance
in cases where dusts and aerosols (blue haze) as well as organic substances are present.

Low operating costs
thanks to low maintenance and cleaning expenditure, significantly less fresh water consumption as compared with SENA because of system-based recondensation from the exhaust gas, and low system pressure loss.

High levels of availability
thanks to the two-stage design of the electrostatic precipitator stage and recirculating water developed specifically for the wood based panel industry. To keep the system operating reliably over the long term, it is extremely important that all the spray systems function correctly at all times. Additionally, the recirculating water has to reach a level of quality that makes it suitable for the cleaning function, as the caking that results from insufficient cleaning is critical to operational safety. If the spray systems fail and these coatings dry out as a result, this presents a significant issue as the coatings cannot be cleaned with normal water and pose a latent risk of fire.

Do you have any questions?

Service is always a key part of our portfolio.

Thomas Kreuzhuber

Head of Sales
Panels Industry

Tel+43 7752 905-5257 t.kreuzhuber@scheuch.com

Wet electrostatic separation

Wet electrostatic separation: basic principle and description of the process

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