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A COMPACT GRANULAR BED FILTER FOR IGCC HOT GAS CLEAN-UP
4th International Freiberg Conference on IGCC & XtL Technologies
May 4th,
2010
Kavitha
Pathmanathan
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Presentation Outline•
Motivation
•
Objective•
Introduction-
Working Principle of Panel Bed Filter (PBF)
-
Filtration Mode-
“Puff-back”
Mode
-
New Filter Design
•
Experiment-
Operating Parameters
-
Setup
•
Results and Discussion•
Conclusion
•
Further Work
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Motivation
•
To develop a reliable high temperature gas cleaning unit
WHY
high temperature?
•
Efficient conversion of fuel to energy in power plants•
Protection of downstream process equipments
•
Environmental regulations
4
ObjectiveTo build and test a new Panel Bed Filter design
Improvement aims reducing: 1. Number of gas-entry surfaces per unit module2. Number of modules per unit filter3. Filter footprint4. Initial and residual pressure drop
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Filter cakeremoved
Filter cakeremoved
Introduction -
Working principle of PBF
Granular mediumLouver
Clean gas
Filter cake
Dusty gasDusty gas
Gas Pulse
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Introduction – Filtration mode
Clean granular medium
Dirty GasClean Gas
Dirty GasClean GasFilter cake
rootsDirty GasClean Gas
Filter cake
Clean Gas Dirty Gas
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Introduction – Puff-back mode
Filter cakeOutermost
layersGas pulse
Local failure
Filter cakeOutermost
layers
Gas pulse
Body movement
gap
Gas pulse
Gap closing with new granular
Granular bed settled
Filter-cake roots remain intact
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Introduction – New Filter vs. previous design
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Introduction – Lab scale rig
Dirty gas compartment
Inlet cone
Feeding container
Outlet cone
Clean gas compartment
Collecting container
40 mm
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Experiment –
Operating ParametersFiltration dust:Arizona test dust, A1 & A2• Loose bulk density: 650 g/m3
• Mean diameter: 9 & 4 μm
Filtration medium:Sintered Bauxite• Sphericity: 0.9• Density: 2040 g/m3
• Mean diameter: 0.662 & 0.458 mm
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Experiment –
Operating Parameters
Operating Conditions DetailsTemperature 20 °C,120 °CVolume flow 6-35 m3/hFiltration velocity 2.50 to 14.94 cm/sInlet dust concentration 2–18 g/m3
Tank Pressure 7 bar absolutePulse duration 30 -
50 ms
Puff-back pressure drop 650,1500, 2000, 2500 PaSpill during each puff-back 150–200 g
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Experiment - Setup
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Results – Clean-bed Pressure drop
0
100
200
300
400
500
600
0 2 4 6 8 10 12 14 16Velocity [cm/s]
Cle
an-b
ed P
ress
ure
drop
[Pa]
New design-Filter tray Previous design-L10-56
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Results -
short term
0
200
400
600
800
1000
1200
1400
1600
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320
time [min]
Δp
[Pa]
0
1
2
3
4
5
6
Filtr
atio
n ve
loci
ty [c
m/s
]
Pressure drop Filtration velocity
1500 Pa
5 cm/s
150 Pa170 Pa 175 Pa
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Results - short term
0
200
400
600
800
1000
1200
1400
1600
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280time [min]
Δp
[Pa]
0
5
10
15
Filtr
atio
n ve
loci
ty [c
m/s
]
9.5 cm/s
1500 Pa
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Results – Inadequate cleaning
0
200
400
600
800
1000
1200
1400
1600
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160time [min]
Δp
[Pa]
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Results -
long term -
9,4 cm/s, 2 g/m3
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940414243
Filtration cycle
Δp
[Pa]
Δp after cleaning Δp before cleaning Δp at start-up
2000Pa
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Results –
extreme conditions: 3 cm/s, 18 g/m3
0
200
400
600
800
1000
1200
1400
1600
0 100 200 300 400Filtration time [min]
Δp
[Pa]
0
2
4
6
8
Filtr
atio
n ve
loci
ty [c
m/s
]
dP Filtration velocity
1500 Pa
3 cm/s
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Results –
PSD -
coarse particles
0
10
20
30
40
50
60
70
80
90
100
0,1 1,0 10,0 100,0Particle Size (µm)
Cum
ulat
ive
Volu
me
(%)
after experiment before experiment
7 μm4 μm
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Conclusion↓ number of louvers per unit module by ↑ gas-entry surface area per unit louverConstant residual pressure drop → sufficient pressure pulse transmitted during puff-back mode
Compared to previous panel bed filter designs:Lower initial and residual pressure dropLonger filtration cycles → reduced puff-back frequency
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Future work
•
Details
studies with
d50
= 4 μm•
SEM analysis of the filter cake structure
•
Emission/Penetration test•
Higher temperature
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THANK YOU FOR YOUR ATTENTION