5 - CFBC - Comp[1]. Ppt
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Transcript of 5 - CFBC - Comp[1]. Ppt
8/12/2019 5 - CFBC - Comp[1]. Ppt
http://slidepdf.com/reader/full/5-cfbc-comp1-ppt 1/14
CFBC DESIGN
COMPARISION
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Comparison with other Design
Parameter Lurgi-
Lenges ( A)
U- Beam (B) CVL
(C)
1.Solid
particleseparation
External
uncooled Hotcyclone
In furnace &
external – UBeam( many
rows)
External water
cooled hotcyclone.
2. Solid
separatorconstruction
Uncooled, Hot,
Mechanical typelarge cyclone
with 300-350
mm thick
refractory lined
Uncooled, “u”
beams banksuspended from
top, inside the
flue gas path,
outlet of
combustor
Water cooled
membrane type, mechanical
construction
with 25-50 mm
refractory
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Comparison with other Design
Parameter Lurgi-
Lenges ( A)
U- Beam (B) CVL
(C)3.Expansion
of Solid
particle
separator
Hot cyclone-
moves upward.,
Combustor movesdownwards &
requires very
large special
expansion joint -
Critical
In furnace &
external – U
Beam. No issue
External water
cooled hot
cyclone.- Bothcombustor &
Cyclone moves
downward
together- no issue
4.Supports forseparator
Bottomsupported
Suspendedfrom top of
extended wall.
Lot many
opening on the
roof.
Top supported
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Comparison with other Design
Parameter Lurgi-
Lenges ( A)
U- Beam (B) CVL
(C)
5.Solid
particle
separator –
efficiency
High Relatively less
than Hot cyclone.
It largely depends
on “recirculation
effect” at “U”beam
lower part
High
6. Solid
recirculationlocation
Bottom of
combustor. Butportion of solids
are cooled in
the FBHEs
Recirculation is
falling at the high
elevation in the
combustor.
Sufficient time is
not given for
combustion of
particles which are
reentering
All collected
solids particlesare entering in
the lower
portion of
combustor&
have more time
in combustor
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Comparison with other Design
Parameter Lurgi-
Lenges ( A)
U- Beam (B) CVL
(C)
5.Solid
particle
separator – shape
retaining
Hot cyclone-
maintenance on
the refractory
U Beams may
undergo erosion &
possibility to gettwisted leading to
out of position and
gas leaning
affecting ash
collection
efficiency. Needsinspection
Water cooled hot
cyclone rugged
construction beingalmost circular.
Small refractory
touch-ups.
6. Location of
separator
External to
combustor
In furnace
combustor
beams uncooled
may face
erosion .
External to
combustor
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Comparison with other Design
Parameter Lurgi-
Lenges ( A)
U- Beam (B) CVL
(C)
7. Success of CFB
process
High Relatively less
than Hot cyclone
due to collectioneffiency.
High
8. Dust loading
at second pass
1.0 More than 1.7
as the ESP first
hopper ash isre-injected into
the combustor
1.0
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Design superiority
• Due to above listed differences CVL CFB
design is superior to U- Beam.
• Our reference list is the testimony for the
design superiority in such a short span of
introduction.
8/12/2019 5 - CFBC - Comp[1]. Ppt
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Additional re-injection
is done.
8/12/2019 5 - CFBC - Comp[1]. Ppt
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CFBC DESIGN WITH COLD CYCLONE
• UPPER FURNACE / HORIZONTAL PASS IS PACKED WITH
HTS (SUPER HEATER, EVAPORATOR & ECONOMISER
TOP BANK)
• HIGH CONCENTRTAED SOLIDS PAASING OVER ABOVE
HEAT TRANSFER SURFACES
• THE LIFE OF HEAT TRANSFER SECTION (HTS) IS INFERIOR
TO HOT CYCLONE
• THE VELOCITY IN THIS DESIGN IS LOWER THAN
VELOCITY FOLLOWED FOR CFB TECHNOLOGY
• COLD CYCLONE IS OPERATING AROUND 450° C GAS
TEMPERATURE. THE COLLECTION EFFICIENCY IS
INFERIOR TO HOT CYCLONE OPERATING AROUND 850 TO
900 °C
• AS THE COLD CYCLONE IS BOTTOM SUPPORTED & THE
RETURN LEG TO THE CUMBOSTOR IS AT 45O ° C, THERE IS
A DIFFERENTIAL THERMAL EXPANSION BETWEEN
COMBUSTOR & CYCLONE / RETURN LEG
• MORE UNBURNT CARBON LOSS DUE TO REDUCED
COLLECTION EFFICIENCY ( COLLECTION EFFICIENCY WILL
BE SLIGHTLY BETTER THAN BUBBLING BED DESIGN)
• THE LIFE OF HTS CONSIDERING HIGH ASH % IN INDIAN COAL
IS EXPECTED TO BE LOW.
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Typical CFBC Boiler