A CLEAN AFFAIR

When the ancient Romans invented opus  caementitium, the predecessor of concrete, they could certainly not have imagined  that people would still use it as a construction material some 2000 years later. The  Viaduct, the Pantheon, and the Elbe Philharmonic Hall are made of this universal  building material.

There is almost nothing that cannot be  built with concrete. The building material owes its popularity to its flexibility and  nearly unlimited application possibilities  and is able to absorb high compressive forces.

The basic mixture nowadays contains  cement, aggregate (sand, gravel) and water. Although the industry makes efforts to  turn it into a relatively ecological building  material, cement production is energy-intensive and releases a lot of dust particles.  In cement plants, raw materials such as  limestone, clay, sand and iron ore are fired in special kilns in a continuous process.  These materials are then finally ground after adding gypsum, which delays the  curing speed.

To reduce fine dust particle emissions to  the required emission limit, filter bags are used for hot gas filtration – for example  made from the high-temperature-resistant polymer by Evonik. P84® polyimide fibers are well known for their high filtration  efficiency thanks to their multi-lobe design and high surface area. They retain a much  higher permeability throughout their lifecycle. This results in significant reductions  in the energy consumption of the fan that keeps the gas flow at a constant level.

Filter media made of P84® polyimide fibers by Evonik therefore not only cut back on  fine dust particle emissions, but also reduce  energy costs.

Worldwide, more than 150 cement kilns  are cleaned with P84® filter bags. In China alone, about 100 cement plants rely on  polyimide fibers from Evonik. Based on  the energy savings, the reference plants of  Evonik reduce CO₂ emissions by approximately  60,000 metric tons a year.