1
A new HEPA solution for gas turbine inlet
air filtration
Tom Kelmartin, PE
W.L. Gore & Associates, Inc. March 14, 2013
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Agenda
• The Problem
• What is HEPA Filtration?
• New HEPA Filtration Solution
• Case Studies
3 2013 W. L. Gore & Associates
The Problem
• Gas turbines consume enormous amounts of air for combustion – GE 7FA: 360 Billion Ft3/year
• That air contains contaminants large and small – Dirt, salt , moisture, sand, soot, insects, corrosive gasses….
• Dirty air causes lost efficiency and can ultimately destroy a turbine – Compressor fouling, blocked cooling passages, blade erosion,
low and high temp corrosion, foreign object damage
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The Problem
• Inlet air filtration aims to reduce contaminants in the air
stream without imposing a large pressure drop penalty
• Conventional filters are very inefficient at capturing sub-
micron particles and allow liquids and dissolved
contaminants to pass
• HEPA filters are better at capturing submicron particles,
but in the past have been challenged by relatively high
pressure drops and limited life
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Sub-Micron Distribution in Urban Air
Particle Distribution (urban)
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0.8
0.9
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Particle Size [µm]
Particle
Number
(normalized)
100 times more 0.1μ particles than 0.5μ
Visible particle = 40µ
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Particle Size Range of Current
Standards (Don’t measure below 0.3µ)
Particle Distribution (urban)
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0.5
0.6
0.7
0.8
0.9
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Particle Size [µm]
Particle
Number (normalized)
EN779
ASHRAE 52.2
US Standard EU Standard
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HEPA Standard EN1822 Addresses <0.3
Micron Issue
Particle Distribution (urban)
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0.5
0.6
0.7
0.8
0.9
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Particle Size [µm]
Particle
Number (normalized)
EN779
ASHRAE 52.2
EN1822
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To Capture the Performance of HEPA Filters,
Need a Different Test (EN1822) and Scale
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Particle Size [µm]
Particle
Number (normalized)
0
10
20
30
40
50
60
70
80
90
100
Particle
Capture
Efficiency [%]
Cellulose
Nanofibers / Synthetic
Nanofibers / Cellulose
MERV15/F9
GORE H12/E12
MPPS*
Minimum required for H12 rating
*Most Penetrating Particle Size
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Filter Classifications
>99.5%
>95%
>85%
95% ≤ Em
85% ≤ E1 ≤95%
95% < E1
80% ≤ Em ≤95%
75% ≤ E1 ≤85%
80% ≤ Em ≤90%
E1 <
75%
Efficiency
MERV
15
MERV
16
F9 0.4μm/
0.3-1.0 avg.
H10/E10 MPPS
H11/E11 MPPS EPA/HEPA
Filters
H12/E12 MPPS
MERV
14
F8 0.4μm/
0.3-1.0 avg.
Fine Filters
MERV
13
F7 0.4μm/
0.3-1.0 avg.
EN1822 2005/2009
ASHRA
E 52.2
EN779 Particle Size Filter Class
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What is a HEPA Filter?
HEPA Rating Efficiency at
MPPS
H10/E10 > 85%
H11/E11 > 95%
H12/E12 > 99.5%
• Defined by EN1822 standard. Were called “H”, now “E”
ratings
• Rating is based on the minimum capture rate of the
Most Penetrating Particle Size (MPPS), typically
about 0.1 microns
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There Are Different HEPA Ratings For a
Reason
Filter Grade
2
4
6
8
10
12
14
Uncaptured
Pollutants
[kg/yr]
Representative pollutants which
pass through a 25 MW turbine
during one year of operation
F9 H10 E12 GORE® Turbine Filter
29 lb/yr
135X
12.3 lb/yr
X= 0.09 lb/yr
F9
Filter Grade
(MERV 15)
E10
Filter Grade
GORE®
Turbine
Filters
Best
MERV
15 Filter
Turbine will
still foul
due to low
efficiency
filters
13 2013 W. L. Gore & Associates
Pre-filter Layer removes
Bulk of large Particles
High Efficiency Membrane Removes
Submicron Dust, Water, and Salt
High Strength Backer
Provides Burst Strength
GORE® Turbine Filters: High Efficiency (E12)
with Low Pressure Drop
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GORE Membrane Technology Waterproof Media Provides Water & Salt Retention
Air can pass
through the membrane
Salt dust, water, and aqueous salt
solutions are repelled
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Stopping the Fouling from small particles
Example of benefits realized by Turbine
Operators
Overview
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Coastal Operation With Coal Dust,
Losing 10% Power Between Offline
Washes - (RB211-30MW) - UK
Coal Yard
Plant
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Constant Power Output with Gore Filters
Coastal Power Plant (RB211-30MW) - UK
Current Filters
3 off-line washings/yr.
-5
-4
-3
-2
-1
0
1
2
3
4
5
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
Days
Po
we
r V
ari
an
ce
fro
m
co
rre
cte
d t
arg
et
(MW
)
F9 standard filter
GORE Turbine Filter
offline compressor
washing and filter
replacement
offline
compressor
washing
Gore Filters
0 off-line washings/yr.
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Reduced Engine Wear:
Coastal & Coal Dust - (RB211-30MW) - UK
20,000 hrs w/ no on- or off-line
washes
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Coastal Petrochemical Plant (Texas) That
Cannot Shutdown for 1 Year
GORE® E12 Turbine
Filters With
Coalescers
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Compressor Efficiency
Power Load
Temperature
Frame 6B 8,000+ hrs
No Wash
Constant Power Output with Gore Filters Petrochemical Plant (GE Frame 6B - 35MW) -
Texas
21 2013 W. L. Gore & Associates
Constant Power Output with Gore Filters Petrochemical Plant (GE 6B – 35MW) – Texas
90.2% (GORE)
87.6% (F8)
34.4 MW (GORE)
31.0 MW (F8)
7,850 Hrs
Compressor Efficiency
Power Load
GE Frame 6B
3.4 MW Gain
2.6% Gain
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LM6000 after >2 years with GORE® Turbine Filters
After 18500 hrs.
After 8500 hrs.
After 15075 hrs.
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Clean Power Plant Turbine – Oregon Mitsubishi 501G (265MW)
After 2000 hours After 4000 hours After 10,000 hours
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Eliminating Off-Line Washes - Confirmed
via Boroscope and Wash Water
Comparison
Current
Gore
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GORE® HEPA Turbine Filters Eliminate
Compressor Fouling:
Simple retrofit
• Similar initial pressure drop
• Similar filter life
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Should I Invest in HEPA Filtration?
1. Compare power output versus previous experience. Power output will be effectively constant with Gore filters. Can also measure compressor efficiency as a proxy for power output
2. Quantify value of stopping off-line washes (availability, cost of shutdown with no power output). Gore product eliminates off-line washes
3. Quantify value of constant heat rate versus previous increases, fuel savings
4. Compare reduced costs due to elimination of extensive compressor section cleaning during scheduled major maintenance
5. Measure blade or rotor corrosion rates over time.
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W. L. Gore & Associates GmbH
Wernher-von-Braun-Str. 18 • D-85640 Putzbrunn •
Germany
Phone: +49 89 4612-2211 • Fax: +49 89 4612-2302
E-mail: [email protected]
www.gore.com
W. L. Gore & Associates, Inc.
101 Lewisville Road • Elkton, MD 21921 • USA
Phone: +1 410 506-3300 • Fax: +1 410 506-3494
W. L. Gore & Associates GmbH Middle East - Abu
Dhabi
Al Niyadi Building • Airport Road • Abu Dhabi • UAE
Phone: +971 2 4437749 • Fax: +971 2 4437748
MORE POWER, LESS
WEAR
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