Key Benefits

  • Improved fine particulate removal
  • Energy savings
  • Lower total cost
  • Reliable performance

Upgrade your ESP with our low-cost, easy-to-install hybrid filter

When you need to improve particulate matter capture using your existing ESP, you have several choices. These include enlarging your existing ESP, installing new baghouse or fabric filters, or upgrading your existing ESP with a hybrid filter.

Enlarging an ESP or installing fabric filters, however, comes with significant challenges. The space around the existing ESPs is often too limited to allow for adding the fields necessary for ESP extensions or installing new fabric filters. Fabric filters require new fans to counter increased pressure drop and frequent bag replacements.



Key objectives with an ESP upgrade include productivity, reliability, and lower total cost of ownership. FLSmidth’s hybrid filter is the right solution when you need to meet these objectives. We develop air pollution control solutions tailored to your operations and to help meet the most stringent particulate matter emission standards.



Hybrid filters offer many advantages, including efficient particulate removal and low installation and operating costs. In a hybrid filter, one part of your ESP continues to function as an ESP while the remaining part of the filter is modified to function as a fabric filter.



Our hybrid filters:

  • Improve PM capture, especially that of fine particulates
  • Deliver energy efficiencies by combining the best of ESP and fabric filter technologies
  • Meet PM emission limits reliably
  • Lower initial and ongoing cost compared to ESP enlargement or fabric filter only solutions
Plant_hybrid filter

What you can expect from our hybrid solution

Our solution is a true hybrid filter that provides the highest levels of filtration of coarse and fine particles in all operating conditions. It is a low-cost, low particle emission solution, ideal for ESP upgrades. With the hybrid filter, you can use your existing ESP casing and footprint, smartly outfitted with the best in filtration technology. Compared to a pure fabric filter solution, the wear on the fabric filter bags is lower due to fewer cleaning cycles, which means a longer life for the fabric filter bags. Power consumption is also low, as reduced dust load on the filter bags means that pressure drops are eliminated.

Hybrid filter

How does the FLSmidth hybrid filter solution work?

First, we add a new fabric filter section to capture and remove fine particles from your emissions. Then we replace the roof of the last sections of your ESP with a fabric filter system complete with top boxes with tube sheets for filter bag support and jet-pulse cleaning nozzles. The upstream ESP section of the hybrid filter captures the majority of the dust particles from your emissions, and the gas stream with reduced dust load is then filtered by the fabric filter downstream. The hybrid filter ensures optimum particulate removal efficiency at all times. It is also less expensive to install than a new fabric filter and has lower operating costs.

Reliable, low-cost particulate emissions capture with a hybrid filter

Improved particulate removal performance
One part of your existing ESP continues to function as an ESP, collecting the majority of the large dust particles. The downstream portion of your ESP functions as a fabric filter for removing fine particulates. The result? Improved, consistent particulate removal by combining two tried-and-tested filtration technologies in a single installation.
Better performance with energy savings
The presence of an ESP means reduced dust in the fabric filters. This translates into fewer cleaning cycles and lower pressure drop, resulting in lower compressed air consumption. Overall, you get better performance without increasing your energy consumption.
Lower total cost of ownership
Our hybrid filter uses your existing ESP casing, which means your equipment costs are lower compared to installing a new fabric filter system, and installation takes days not weeks. Every aspect of our system, from the filter bags, gas flow, to the cage is designed to increase bag lifetime and reduce overall cleaning and maintenance cost.
Reliable performance
With our hybrid filters, you can expect consistent emissions reduction under varying operating conditions.

Hybrid filters with the best of ESP and fabric filter technology

The FLSmidth hybrid filter solution involves keeping one or two existing ESP sections as the pre-separator. A fabric filter is then installed in the remaining ESP housing, forming a compact hybrid particulate collector.

The dust pre-separator reduces the amount of dust particles and mass that the fabric filter has to deal with, which makes filtration easier and reduces dust emission peaks.


Moreover, because the dust cake on the filter bag is less compact, it is easier to remove. Using the ESP section as a pre-separator removes the coarse and very fine particles, altering the particle size distribution before the bag filter, where an accumulation of the intermittent fraction occurs.


In a pure fabric filter, efficiency decreases gradually as particle size decreases. But with a hybrid ESP and fabric filter, dust emissions are lower and filtration is generally more effective.


Long-lasting filtration bags


Our hybrid filter is designed to make filtration bags last longer, requires minimal maintenance and lowers your overall cost of operation.


The filters come with a perfect bag-to-cage match that improves distribution of dust and gas. The long filter bag technology fits compactly, meaning a smaller, more compact installation with reduced footprint. The proprietary, star-shaped cage design minimises abrasion and flex fatigue on the bags by reducing the contact points between the cage and the bag.


Unique gas distribution system


FLSmidth’s hybrid filter technology has several important features that help to reduce your total cost of ownership. One of these is the specially developed gas distribution system.


By improving the flow of gas, and separating dust and finer particles, we minimise dust load on the bags, which means fewer cleaning cycles and compressed air consumption needs. In addition, our FLSmidth Smart Pulse Controller® automatically adjusts pulse duration, interval and pressure, which further reduces the need for compressed air, extending the durability of the system.

The hybrid filter is the latest technology in filtering. We are very proud at ArcelorMittal Zenica to be the first company in the world to have successfully installed it, and we can say that we have fully achieved our goal to reduce dust emissions. This project brings significant improvements both in terms of our environmental performance and the sintering process in the plant.

Emir GrmalicDirector of ArcelorMittal Zenica’s sinter plant and project leader

Overview of options

Fabric filter online Fabric filter semi-online Fabric filter offline Hybrid
Compartments  Yes Yes  No  Yes,
if semi-offline 
Hopper modification
Yes No No No
Maintenance in operation Yes No No No
Pressure drop (mmWg) 130-150 130-150 120-150 100-120
Sensitive to CO No No No Yes
Compressed air
consumption index
100 100 100 70
Bags replacement time
2 years (felt bags)
5 years (fiberglass)
2 years (felt bags)
5 years (fiberglass)
2 years (felt bags)
5 years (fiberglass)
3 years (felt bags)
6 years (fiberglass)



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