Membranes for Exhaust air Filtration
Clean air through multiFlon® membranes for highly efficient filter media
Until the 1980s, exhaust-air from industrial plants often entered the environment completely unfiltered. Gravity separators or scrubbers were essentially used for exhaust-air purification. Electric separators significantly increased the efficiency of exhaust-air purification systems after their introduction.
Nevertheless, very high amounts of toxic and carcinogenic fine dust were released into the environment from industrial plants. Filtration separators were already state of the art in other applications, but with the usual materials only depth filters could be produced, which saturated very quickly at very high fine dust loads and then had to be replaced – which was not feasible for high continuous dust volumes due to the maintenance effort with constant downtime.
With the development and introduction of highly effective filter systems, equipped with surface filters made of ePTFE membranes that were fully regenerable, a breakthrough in industrial dust removal was achieved. Since then, the majority of industrial plants have been equipped or retrofitted with this technology, thus significantly reducing fine dust emissions.
To protect people and nature, the further reduction of harmful emissions must be decisively pursued. Our multiFlon® membranes for exhaust-air filtration were developed with this in mind and offer outstanding separation performance thanks to their small pore size and extremely uniform distribution. They are chemically inert and can be used at high temperatures – perfect for adverse conditions. Due to the nevertheless good air permeability of the filter medium, efficient system operation is guaranteed.
In figures: The effectiveness of multiFlon® membranes for exhaust-air filtration
Conversion of a cement plant from electrostatic precipitators to ePTFE surface filters
- Exhaust gas volume mill operation: 520,000 m³/h at 95°C
- Exhaust gas volume furnace operation: 490,000 m³/h at 170°C
=>The fine dust emission of the cement plant could be reduced by approx. 96% compared to the use of conventional ePTFE membrane filters and by approx. 99.6% compared to the original electrostatic precipitator by using multiFlon® ePTFE membrane filters!
a) Electrostatic precipitator
Total dust emission with electrostatic precipitator: approx. 10 mg/m³, => 22,780 kg/year for mill operation
Fine dust emission with electrostatic precipitator: approx. 10 mg/m³, => 21,460 kg/year for furnace operation
Total emissions during operation with electrostatic precipitator at 50% capacity utilisation: 44,240 kg/year
b) ePTFE membrane filter
Fine dust emission with ePTFE filter: approx. 1 mg/m³, => 2,280 kg/year for mill operation
Fine dust emission with ePTFE filter: approx. 1 mg/m³, => 2,150 kg/year for furnace operation
Total emissions during operation with membrane filter at 50% utilisation: 4,430 kg/year
c) novel membrane filter with multiFlon® ePTFE
Fine dust emission with multiFlon® ePTFE filter: approx. 0.04 mg/m³, => 91 kg/year for mill operation
Fine dust emission with multiFlon® ePTFE filter: approx. 0.04 mg/m³, => 86 kg/year for furnace operation
Total emissions during operation with high-tech membrane filter at 50% utilisation: 177 kg/year