Engineering Fiber Blends for Enhanced Filtration Efficiency

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Use of Micro Denier Fibers to Improve Pulse Jet
Baghouse Performance
Keith Ogilvie Director, National Filter Media
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Abstract
When conventional needle felts provide inadequate
filtration efficiency, what affordable options
are available? This paper will highlight some
intriguing designs that have been developed by
blending various fibers, both homogeneously and
in composite construction, to achieve higher
filtration efficiencies.
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Briefly as a Cursory Description

• A Homogenous blend is one that consists of
  uniform blending of multiple fibers either of
  different denier sizes, cross section, and/or of
  different fiber types.
• A Composite construction is one that consists of
  a stratification or laying of fibers of different
  denier sizes, cross section, and/or of different
  fiber types on the face side (facing the dust
  stream) versus the back side of the needle felt.
• As one can imagine, there are many variations
  that are available in the construction of needle
  felt.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
General Evolution of Blended Needle Felts
HISTORICALLY                   WOVENS for Shaker
Reverse Air Baghouses   Late 1960s              
             NEEDLEFELTS INTRODUCED (3.0
DENIER)   Early 1980s                           BO
OM of PJBH - 1.5 AND 3.0 DENIER BLENDS   Mid
1980s                             TEFAIRE first
blended fiber/felt. PTFE FG   Early
1990s                           100 1.5 DENIER
IN REGULAR PRODUCTION   Mid 1990s                 
            100 0.7 DENIER IN REGULAR
PRODUCTION   Present               
MICRO-DENIER CAP PRODUCTS
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Depth v. Surface Filtration
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Surface Filtration

• ePTFE Membrane Laminates

• Fiber Caps

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
What about Needle Felt Finishes?
Though this presentation deals with fiber blends,
it is important to recognize that various
chemical treatments and surface finishes might
provide enhanced performance characteristics even
beyond blends as in the case of ePTFE membranes,
which are generally recognized as the PM2.5/MACT
for emissions.
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PTFE - Intrinsic v. ePTFE-Membrane
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Perspective

• Development of fine/micro denier fibers (defined
  as having a fiber diameter of less than 10
  microns) and fibers with unique cross-sections
  are available not only for low temperature fibers
  but now available for most high temperature
  fibers as well.
• Improved needle felting techniques and machinery
  has enabled the proper processing of finer or
  micro denier fibers into new and distinctive
  constructions.
• More stringent emission regulations have created
  the need for more filtration efficient products.
• Better understanding by the Market of the
  Cost/Performance or True Value of higher
  performance needle felts allows end-users to see
  a payback or benefit for using these products.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
What is Denier?
Denier is Weight per unit Length (linear density)
measure of a continuous filament or yarn, used
traditionally in textile industry. Denier The
weight in Grams of 9,000 meters of fiber.
Therefore lower the denier number, finer the
material and higher the denier number, coarser
the material. dtex In most countries other
than the US, denier has been replaced by the
Tex system. So, fiber is measured by the weight
in Grams of 1,000 meters.
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Fiber Comparison Chart
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Comparison of Standard and Micro Denier Fibers
Standard 2.25 Denier Fiber
0.7 Micro Denier Fiber
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Fiber Cross-Section
Blended Designs Can Incorporate Unique Fiber
Cross-Sections
Y-Shaped Cross-Section of P84 Fiber
Round Cross-Section of PPS Fiber
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Illustration of Layered Composite Construction
Dirty Air
Surface Layer typically of finer denier fibers
Felt Substrate
Clean Air
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Structure of Micro-Maxx (Denier Mixture) PPS
Felt With Torcon PPS Fibers
Sketch of Micro-Maxx with Torcon PPS fibers
Torcon 0.9d Torcon 2.7d Mixed Top Batt
Enhances the collection performance
Torcon7.0d Bottom Batt

Results of Micro-Maxx PPS felt
The diameter of Torcon PPS fibers
Torcon Micro-Maxx 0.9d(9.7µm)
1.Extend the useful lifetime of filter bag
Torcon Std. 2.7d(14.5µm)
Torcon Coarse 7.0d(27µm)
2.Lower emission v. traditional felt
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Cross-section of the Micro-Maxx PPS Felt v.
Traditional PPS Felt Structure
Micro-Maxx Felt with Torcon PPS Fibers
Traditional PPS Felt
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Micro-Denier Felts
PM 2.5 Efficiency Testing ASTM D6830-02 35
Lower Emissions Smaller particles captured 45
Reduction in Pulse Cycles Required to maintain
pressure drop 50 Less Dust Penetration Increasi
ng filter bag life 30 Energy Savings Due to
reduced number of pulses
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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Polyester Needle Felt
Polyester Micro-Maxx Standard Polyester
Face Side 0.7 denier polyester 2.25 denier polyester
Scrim Spun polyester Spun polyester
Back Batt 2.25 denier polyester 2.25 denier polyester
Weight 540 g/m2 540 g/m2
Permeability  20 CFM  30 CFM

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Polyester Micro-Maxx

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Homopolymer Acrylic Needle Felt
HPA Micro-Maxx Standard HPA
Face Side 0.5 denier Dolanit 2.5 denier Dolanit
Scrim Spun Dolanit Spun Dolanit
Back Batt 2.5 denier Dolanit 2.5 denier Dolanit
Weight 540 g/m2 540 g/m2
Permeability  20 CFM  30 CFM

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Homopolymer Acrylic Micro-Maxx

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
P84 Needle Felt
P84 Micro-Maxx Standard P84
Face Side 0.9 denier P84 2 denier P84
Scrim Spun P84 Spun P84
Back Batt 2 denier P84 2 denier P84
Weight 475 g/m2 475 g/m2
Permeability  25 CFM  30 CFM

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
P84 Polyimide Micro-Maxx

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
PPS Needle Felt
PPS Micro-Maxx Standard PPS
Face Side 0.9 denier PPS 2.7 denier PPPS
Scrim Spun PPS Spun PPS
Back Batt 2.7 denier PPS 2.7 denier PPS
Weight 540 g/m2 540 g/m2
Permeability  25 CFM  30 CFM

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
PPS Micro-Maxx

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency

• Southern Felt Company, Inc.

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Summary of Benefits

• High separation efficiency
• Low dust penetration
• Excellent throughput
• Low residual dust cakes
• Lower operating costs
• Ambient and hot gas needle felts available
• Affordable v. ePTFE Membrane

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Engineering Fiber Blends for Enhanced Filtration
Efficiency
Acknowledgements

• Southern Felt Company, Inc.