Technologies

Dedusting and filtration

Gas dedusting and filtration apply to processes that generate gases dusted with solid particles. The primary sources of such pollutants are fuel combustion processes (district heating plants, combined heat and power plants), crushing (e.g., cement works), steel smelting and processing (steel mills), or the transfer of bulk products during transport. Certain matter in gases is a threat to the environment and health, so filtration of these gases with the removal of the particulate matter suspended in them is a very important process.

Nowadays, there is an urgent need to take action to protect the environment, to which filtering and dedusting equipment makes a major contribution. They capture harmful components from manufacturing processes and do not allow them to enter the atmosphere.

Providing safe and comfortable working conditions for employees is an equally crucial aspect. Ecoserv has several process solutions and filtering equipment, such as: vertical and horizontal bag filters, cyclone and multi-cyclone dedusters, which are selected and configured individually for the respective process.

Dedusting and filtration technology uses filters made of non-woven filtration fabrics that catch particles of dust from flue gases flowing through the system or, in the case of multi-cyclone dedusters, serve as physical barriers at the initial stage of gas treatment. The treated gases pass through the emitter into the atmosphere, while the captured dust is collected for further management.

We can divide dedusting and filtration equipment into several groups:

Fabric filters

Bag filters are designed for dedusting air, flue, and other gases and removing dry and non-sticky dust. They are used in the cement, lime, foundry, metallurgy, glass, and heat engineering industries to dedust flue gases from power boilers.

Filters with vertical bags
Bag filters with vertical bags with vertical filter bags arrangement in the filtration chamber. The gas enters the chamber, where the fine dust fractions are captured and remain on the surface of the filter fabric. The dust particles end up at the bottom of the chute funnel, 
while the cleaned gas enters the outlet chamber and is discharged outside. Pulsed regeneration of the filter with compressed air occurs cyclically (the time between compressed air pulses is set) or automatically (when the differential pressure exceeds the set value in the filter controller). Dedusted flue gases from the filter are extracted by a draft fan to the emitter.

Filters with horizontal bags
Bag filters with horizontal bags are installed horizontally in the filtration chamber. The design of the bag filter ensures good bag regeneration and cleaning of the bags from dust, and it eliminates the accumulation of dust on the filter bags and thus their clogging as much as possible, which can have a significant impact on their service life. The bag filter’s regeneration with compressed air occurs cyclically or automatically. Dedusted flue gases from the filter are extracted by a draft fan to the emitter.

Horizontal bag filters are designed to dedust flue gases from power station boilers and other contaminated gases. For flue gas dedusting, they ensure the achievement of the required dust emission of less than 30 mg/Nm3 for 6% O2. They are characterized by high compaction of the filter surface in a relatively small space, allowing them to have a compact size.

The filter bags in the horizontal filters have a convenient “snap-ring” fastening implemented, which ensures tightness and ease of assembly. The regeneration of the bags is performed using compressed air.

Compressed air valves integrated into the tank are used for regeneration, significantly improving the valves’ flow conditions and thus better regeneration.

CYCLONE BATTERIES

Cyclone batteries are used for cleaning gases from solid particles (dust). They are made as standard from 3 – 4.5 mm thick steel sheets. The inlet head section may have a HARDOX wear-resistant steel insert to extend its life. Cyclone batteries can also be used as pre-dusters, e.g., for bag filters.

As a result of centrifugal force (thanks to the cylindrical chamber), the flue gases flowing through the cyclones cause the dust to be thrown back onto the wall of the cylindrical shell, where it slows down under the impact of frictional force, and then fall by gravity and is discharged through a chute tightly closed to the gases with a sluice.

HORIZONTAL PASS-THROUGH MULTI-CYCLONE DEDUSTERS

Pass-through cyclones (multicyclones) are mainly used in the power industry for grate boilers as the preliminary dedusting stage. They are designed to capture the most erosive fractions, which contributes to extending the life of cyclone dedusters or filters.

A pass cyclone is constructed from rows of cast-iron cyclones (the so-called swirlers), which swirl the flue gases and cause dust under the impact of centrifugal force, which is thrown back onto the wall of the shell. Here it slows down under the impact of frictional force, falling into the expansion chamber of the pass-through cyclone, and then falls by gravity to the chute closed with a dust discharging sluice. The capacity of one pass-through cyclone depends on the number of pass-through cyclones (swirlers) installed and their diameter.

ELECTROSTATIC PRECIPITATORS

Electrostatic precipitators are an advanced solution for dust removal. They use an electrostatic field to attract and collect dust particles from the flowing gas stream, thus enabling effective air filtration. It is a standard dust removal method used in commercial power generation, heating engineering, and many other technological processes. In electrostatic precipitators, the dusty gas is ionised in a strong electrostatic field, so that the collection electrode attracts the dust grains then fall into the dust tank. These devices are characterised by high operating efficiency and low flow resistance, even for very high gas volumes.

BENEFITS

Thanks to the advanced gas dedusting and filtration technology employed by Ecoserv, we can guarantee a solution that meets the individual requirements of our customers, while reducing pollutants to levels that comply with current emission standards.