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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

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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