© C
BW
Cly
de B
erg
em
ann W
ese
l 10.2
007
-Rev. 5
Introduction to On-load Boiler
cleaning
March 13, 2020Chemistry in Energy Technology
Åbo Akademi University
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23 – Introduction to On-load Boiler Cleaning
Conversion of solid fuel
devolatilisation char
conversion
fuel
particle
drying
CxHyOz
S, N
Ignition/
Volatile
conversion
CO, CO2,
H2, N
Ash
T P
arti
cle
t residence
H2O
CO2, H2O
SOx, NOx
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3
Coal- and Coal Ash Composition
Coal Analysis
C (ar) [%] 47.94
H (ar) [%] 2.85
O (ar) [%] 4.97
N (ar) [%] 0.66
S (ar) [%] 0.52
Ash (ar) [%] 37.96
Moisture (ar) [%] 5.10
Volatiles (waf) [%] 33.0
Hu (waf) [MJ/kg] 32.2
Ash Analysis
SiO2 [%] 56,6
Al2O3 [%] 26,5
Fe2O3 [%] 9,4
CaO [%] 3,9
MgO [%] 1,5
Na2O [%] 0,3
K2O [%] 0,3
TiO2 [%] 1,0
P2O5 [%] -
SO3 [%] 1,3
3 – Introduction to On-load Boiler Cleaning
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4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Si Al Fe Mg Ca K Na P S Cl
Wt-
% d
.b.
Wood
Debris
Bark
Needles
Salix
Timothy
Lucerne
Rape
Barley
Wheat
RC summer
RC spring
Peat Ref
Peat Average
MSW
Coal 1
Coal 2
A. Nordin (1994) Biomass and Bioenergy, Vol.6(5), 339-347
Ash Forming Elements
3 – Introduction to On-load Boiler Cleaning
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5
Flyash Deposits (Coal Biomass)
Coal and 15% olive Coal only
3 – Introduction to On-load Boiler Cleaning
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6
Flyash - Flyash Deposition
3 – Introduction to On-load Boiler Cleaning
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7
Why is On-load Boiler Cleaning needed ?
Give some examples and possible consequence in a boiler:
________________________
________________________
________________________
________________________
3 – Introduction to On-load Boiler Cleaning
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8
Where can we have deposits ?
BFB (Bubbling Fluidized Boiler) boilers
3 – Introduction to On-load Boiler Cleaning
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9
Where can we have deposits ?
CFB (Bubbling Fluidized Boiler) boilers
3 – Introduction to On-load Boiler Cleaning
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10
Where can we have deposits ?
Evaporator / Radiative
Convective
Luvo-Bypass-
Economiser
Luvo
Typical COAL fired boilers
3 – Introduction to On-load Boiler Cleaning
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11
Where can we have deposits ?
RB (Kraft Recovery Boiler) boilers
3 – Introduction to On-load Boiler Cleaning
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12
Wall Deposits
3 – Introduction to On-load Boiler Cleaning
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13
Superheater Deposits (Coal)
3 – Introduction to On-load Boiler Cleaning
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14
Superheater Deposits (Coal)
3 – Introduction to On-load Boiler Cleaning
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15
Superheater Deposits
3 – Introduction to On-load Boiler Cleaning
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16
Economiser Deposits
3 – Introduction to On-load Boiler Cleaning
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Carryover
Fume
Two type of fly ash particles:
Carryover
Mechanical entrainment of BL droplets or
fragment of burning droplet
Fume
Condensation of vapors of Na and K
compounds in the flue gas
17
Deposits (Recovery Boiler)
3 – Introduction to On-load Boiler Cleaning
Carryover
Fume
Dust
Black Liquor
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Deposits in RB - 1st Pain Point
3 – Introduction to On-load Boiler Cleaning
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Unlike Power Boilers, Sootblowers in
Recovery Boiler are operated back to back
continuously to prevent costly plugging
How heavy the fouling can be ??
3 – Introduction to On-load Boiler Cleaning
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Costly On-load Cleaning (sootblower)
operation due to constant running of
cleaning equipment:
• 2,860 ton BL dry solid / day
• 410 ton/hr 100 bar steam prod
• SB consume 8% MCR steam
• 8% * 410 = 32.8 ton/hr
• €15/ton * 32.8 ton/hr
• €4.2 Million / year
Deposits in RB – 2nd Pain Point
3 – Introduction to On-load Boiler Cleaning
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Situation & Solution
Solution
Cleaning devices which are specially
designed for the different cleaning
requirements within a boiler by applying
various cleaning methods and nozzles
as well as nozzles arrangements
Cleaning media
steam/air
water
Critical cleaning parameters can be
flexibly set depending on deposition type
or intensity
This allows for an independent and
variable boiler cleaning
3 – Introduction to On-load Boiler Cleaning
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Situation & Solution
Solution
SMART Cannon Retractable Sootblower
Kinetic energy and
volumetric expansion
Water
Wate
r/S
team
De
po
sit
ion
3 – Introduction to On-load Boiler Cleaning
SMART SCS SMART Clean
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Situation & Solution
Not covered in this presentation:
Off-load Boiler cleaning
Acoustic (Sonic horns) cleaning methods
Explosion methods
Mechnical rapping systems
3 – Introduction to On-load Boiler Cleaning
Rapping Systems
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24Titel der Präsentation
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