New Filter Media for Dry Gas FiltrationNew Filter Media for Dry Gas FiltrationIn-Situ Cleaning of FilterbagsIn-Situ Cleaning of Filterbags

FFC Filter Fabric ConsultingManfred Schobesberger

FOS Umwelt und Filtertechnik GmbH

StatusStatus

Fibres such as: Polyester, PAN, PPS, Fibres such as: Polyester, PAN, PPS, Polyimide or PTFE are converted via Polyimide or PTFE are converted via „needle punching“ into textile fabrics„needle punching“ into textile fabrics

These needle felts are confectioneered These needle felts are confectioneered by sewing or welding into filter bags, by sewing or welding into filter bags, pockets etcpockets etc

PlusPlus

Cost effective and proven manufacturing Cost effective and proven manufacturing leading to excellent filter fabricsleading to excellent filter fabrics

Lately improved by the use of micro Lately improved by the use of micro denier fibres leading to vastly improved denier fibres leading to vastly improved filtration efficiencyfiltration efficiency

Typical Cross Section of a Typical Cross Section of a Needle FeltNeedle Felt

Good surface collection of the dust on the flue gas side

Standard Filter Fabric vs. MicrofibresStandard Filter Fabric vs. Microfibres

Polyester Fabric

Operational Time: approx. 12 Months

Blended Fabric with P84 micro denier fibres on the flue gas side after 24 months - same filter unit

Minus - Disadvantage of Minus - Disadvantage of traditional Needle Felt in this traditional Needle Felt in this

Case PPSCase PPSGiven due to the

mechanical processing of the fabric there are

needle „channels“ allowing dust to

penetrate

Target of the DevelopmentTarget of the Development New, better Fabrics with no Needling New, better Fabrics with no Needling

ChannelsChannels Higher Tensile Strength due to less Higher Tensile Strength due to less

Damage of the Supporting Srim in Damage of the Supporting Srim in ManufacturingManufacturing

Better Filtration Efficiency due to finer Better Filtration Efficiency due to finer Pore StructurePore Structure

Less Cost due to reduced Fabric WeightLess Cost due to reduced Fabric Weight

Water Jet SystemWater Jet System

ResultResult

Homogenious Fabric NO Needling Channels !

Sample from Field TestingSample from Field Testing

Result from a 3 Year Simmulation Test

Table of Mechanical DataTable of Mechanical Data

Traditinal NF (PES)Traditinal NF (PES)

Tensile CD:Tensile CD: 150 daN/5cm 150 daN/5cm

Elongation CD:Elongation CD: 23 % 23 %

Weight:Weight: 550 g/m² 550 g/m²

Air Permeability: 150 l/dm²Air Permeability: 150 l/dm²

Aqua Felt Aqua Felt Tensile CD:Tensile CD: 210 daN/5cm 210 daN/5cm

Elongation CD:Elongation CD: 23 % 23 %

Weight: Weight: 380 g/m 380 g/m22

Air Permeability: 200 l/dmAir Permeability: 200 l/dm22

Online CleaningOnline Cleaning

As a matter of fact filter fabrics in general are As a matter of fact filter fabrics in general are susceptible to a continious increase of differential susceptible to a continious increase of differential pressure due to crust-build up, clogging and pressure due to crust-build up, clogging and blinding on and inside the media. blinding on and inside the media. Changing of bags is very ofter the only alternative Changing of bags is very ofter the only alternative as the system can only handle a certain load.as the system can only handle a certain load.The here introduced method promises relief for The here introduced method promises relief for most of these cases in a very economic way.most of these cases in a very economic way.

The SystemThe System Cleaning without removing the bags from Cleaning without removing the bags from

the tube sheet (in 90% of all cases)the tube sheet (in 90% of all cases) Cleaning is done via high frequecy Cleaning is done via high frequecy

pulsation - no water, no waste waterpulsation - no water, no waste water The dust remains in the filter unit falling The dust remains in the filter unit falling

into the hopper - no stress to the into the hopper - no stress to the environmentenvironment

Efficient procedure - short shut down Efficient procedure - short shut down period!period!

ProceedingProceeding

ResultResult

Felt before cleaningAir permeability: 6 l/dm².min

After cleaning - 150 l/dm².min

Lenzing 1K7 FBB (PTFE)Lenzing 1K7 FBB (PTFE)

Felt before cleaning After cleaning

Surface PicturesSurface Pictures

Before and after cleaning

The Results in ShortThe Results in Short

Only damaged bags and cages will be Only damaged bags and cages will be replacedreplaced

Air permeability back to approx. 80% of Air permeability back to approx. 80% of the new valuesthe new values

Complete job is done by especially Complete job is done by especially trained personnel, no additional costs trained personnel, no additional costs and efforts for the operator!and efforts for the operator!

ReferencesReferences MWI Solingen: 1500 PPS, MWI Solingen: 1500 PPS, ΔΔp 230/110 mm WGp 230/110 mm WG Lenzing: 7000 PTFE, Lenzing: 7000 PTFE, ΔΔp 250/110 mm WGp 250/110 mm WG MWI Goeppingen: 1250 PTFE, MWI Goeppingen: 1250 PTFE, ΔΔp 320/130 mm WGp 320/130 mm WG MWI Helmstadt: 2400 PTFE-P84 MWI Helmstadt: 2400 PTFE-P84 ΔpΔp 280/130 mm WG 280/130 mm WG Bio-MWI Aschersleben: 480 PTFE, Bio-MWI Aschersleben: 480 PTFE,

ΔΔp 240/120 mm WGp 240/120 mm WG BSR – Berlin: 1200 PTFE, BSR – Berlin: 1200 PTFE, ΔΔp 260/110 mm WGp 260/110 mm WG MWI Helsinki: 990 PTFE, MWI Helsinki: 990 PTFE, ΔΔp 260/120 mm WGp 260/120 mm WG