Gas solid flow in a CFB with L-valve and impact of gas distributionchanges in the design

Arenales, J., Perez, V. and Murillo, J.M.

26 September 2014 169th IEA-FBC meeting

Jorge Arenales Rivera

CEDER-CIEMAT

Autovia A-15, Salida 56, 42290, Lubia (SORIA)

e-mail: jorge.arenales@ciemat.es

Tlf:975-281013

Circulating fluidized bed gasifier

• Main design parameters

– Size

• Driser: 300 mm; Hriser: 8800 mm

– Maximum operation pressure: 0.2 bar

– Maximum temperature: 950 ºC

– Gas velocity: 3-6 m/s

– Maximum air gasification flow rate: 300 Nm3/h

– Fuel rate: 100 kg/h

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Circulating fluidized bed gasifier

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Circulating fluidized bed gasifier

• Gas/solids flow performance

– Selection of bed material

– Exit type

• Abrupt exit

– Solids flow control (aireation)

• U-type loop-seal

– Recycle chamber

– Supply chamber

– Horizontal passage

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Bed material

• Bed material

– Silica sand

204 μm/428 μm

ρp ~2500 kg/m3

ρbulk ~1520 kg/m3

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Geldart, D. Powder Technology, 1, 285, 1973

Bed material

• Granulometry – Conventional method

• Sand 204 μm

• Sand 428 μm

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Particle diameter (mm)

204

428

CFB Cold flow model

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CFB Cold flow model

• Main design parameters

– Plexiglas model

• Driser: 192 mm; Hriser: 4550 mm

• Dstandpipe: 92 mm; Hstandpipe: 2700 mm

• DL-valve: 92 mm; Lhorizontal passage: 480 mm

– Maximum operation pressure: 0.2 bar

– Gas velocity: 3-6 m/s

– Maximum air gasification flow rate: 600 Nm3/h

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Bed material selection

• Sand a) 428 μm– Solids inventory: 25-35 kg

– Aireation flow rate: 50-70 L/min

– Superficial velocity: 5-6 m/s

• Sand b) 204 μm– Solids inventory: 25-35 kg

– Aireation flow rate: 25-46 L/min

– Superficial velocity: 3.5-5 m/s

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Solids flow measurement

• External solids flow

– Butterfly valve

– Graduate Pipe

• Internal solids flow

– Non-isokinetic probe

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Solids flow measurement

• External solids flow

– Solids mass flux (Gs)

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Solids flow measurement

• Internal solids flow

– Solids mass flux

Preliminary results (non-isokinetic probe)

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Solids inventory

(35 kg)

Aireation flow rate

(37 L/min)

Internal solids

mass flux (kg/sm2)

External solids

mass flux (kg/sm2)

us (4 m/s) 27 6.4

us (4,5 m/s) 31.8 10.6

Circulating fluidized bed gasifier

• Gas distributor design

– Riser

• Bubble-cap type

(abrasion)

– Loop-seal

• Perforated pipes

(Supply chamber)

(Recycle chamber)

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Non-mechanical valve

• Supply chamber

– Aireation tap

(L-valve design)

• Recycle chamber

– Perforated pipes

– Perforated plate

– Porous plate

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Solids flow measurement

• Perforated plate

– Staggered

distribution

– Dhole: 1 mm

– Step: 0.129 mm

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Solids flow measurement

• Porous plate

– Glass filter

– Por. 2 P100

(ISO 4793-80)

– Poresize 40-100 μm

– Diameter: 140 mm

– Tickness: 10 mm

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Future work

• Test different bed materials

• Experiments with an U-type loop-seal in a

CFB cold flow model

• Re-design of loop-seal in the circulating

fluidized bed gasifier pilot plant

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Thank you for your attention

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