GEA Separation Ash Leaching 1 Brazil.pptx

GEA Mechanical Equipment
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GEA Separation – Minerals and Chemicals
Pulp and Paper
 Ash Leach
Tore Hartmann

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2
The kraft chemical recovery cycle
including the ash leaching process

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Hot Water
Na2SO4
Cl and K-salt
in solid phase
Ash Na2SO4 in solid phase
Na2SO4 in solution
K+ Cl-
K+
K+
Cl-
Cl-
Na2SO4
Na2SO4
Solid (Na2SO4)
Liquid
Recycle
AGITATION SEPARATION
Back to the
liqour cycle
To water
treatment
In ash leaching tank In decanter centrifuge
Back to ash leaching tank
Principles for ash leaching
In reality, Na2SO4 is not
the only component in
the solid phase.

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Alkali salt
[Na2SO4]
~
Liquid&
chemicals
“white liquor”
( sodium hydroxide
& sodium sulphide )
Digester
Chips (wood)
Pulp to
further
processing
Electrostatic
Precipitator
RBS = recovered boiler salts
Weak black liquor
Strong black liquor
Flue gas,
ash, salts
Recovery boiler
Evaporator
Energy
purge
to disposal
Cl- and K+
Hot water
vent
Leaching tank
Slurry pump
Decanter
Feed T: 95°C
Application – Ash Leach – Process description
Ash leaching decreases Cl- content in the recovery boiler
and at the same time recover of Na and SO4.

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• Reduced chemical consumption, due to increased recovery of sodium
sulphate (Na2SO4)
lower the cost of TOC of this unit
• Significant lower environmental impact and disposal costs (some of the
metals from the ESP – like cadmium – are toxic and can not simply
dumped)
support customers comply with recent environmental legislation.
• Improved boiler performance due to the removal of Cl- and K+ ions
• less plugging in boiler → increased boiler capacity and less production
losses (Cl- and K+ cause reduction of the boiling point)
• decreased risk of corrosion of boiler tubes
resulting in fewer unplanned stops and less maintenance for the boiler
The main benefits are cost reduction due to less
corrosion and higher boiler efficiency.
Main Benefits of the Ash Leach System

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The boiler plugging causes reduction of efficiency.
What happens if the Cl- and the K+ causes plugging?
Boiler
Rigid Molten
Layer
Flue Gas
450 °C
850 °C
T0 T70
480 °C
Rigid Molten
Layer
480 °C 520 °C
580 °C
750 °C
T0 T70
Boiler
Rigid
850 °C
Flue Gas
Group Chemicals & Minerals

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7
process flow diagram of an ash leaching process
The ash is mixed with warm water at 90°C in an agitated
leaching tank which results in the formation of a slurry. The
slurry is a partly diluted mixture which contains suspended
solids and diluted solids in water.. Most of the chlorides and
potassium dissolve in the water while the main part of
Na2SO4 remains solid.
The slurry is transferred from the leaching tank to a decanter
centrifuge where liquid and solids are.mechanically clarified
by centrifugal force. The pH level of the slurry must be
adjusted for different types of ash. This is achieved by dosing
acid into the slurry
A 2-stage leaching system has two leaching/separation
systems working in series. This eliminates the need for
dosing acid and improves overall total life cycle cost
The recycled ash containing Na2SO4 of the underflow is
mixed with virgin black liquor in the mix tank and returned to
the chemical recovery cycle. The overflow contains the main
part of the potassium and chloride. One part of this liquid is
discharged via the water treatment system and the remaining
part is returned to the leaching tank. By adjusting the amount
of recycled reject, the selectivity of the removal efficiency of
Cl- and K+ and the recovery efficiency of Na2SO4 is
controlled.

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As NaCl and KCl is becoming increasingly dissolved with
rising temperature, sodium sulphate is not.
Solubility of the alkali chloride and alkali sulphate
in PURE solutions
0
10
20
30
40
50
60
0°C 20°C 30°C 50°C 70°C 90°C
Temperature [°C]
Solubilty
[g
/
100g
H2O]
NaCl
KCl
Na2SO4
K2SO4

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selectivity of the removal efficiency of
Cl- and K+ and the recovery efficiency of Na2SO4
When the recycled fraction is decreased the removal efficiency of
chlorides and potassium will increase.

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A 2-stage leaching system has two
leaching/separation systems working in series

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dissolved and suspended solids in the process
streams entering and exiting the decanter centrifuge
slurry
reject recycled ash
H2O + dissolved solids
Suspended solids
H2O + dissolved solids H2O + dissolved solids
Suspended solids

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In reality this separation depends on the
centrifugal force, which include the density
difference between solid and liquid phase,
viscosity, particle size and mechanical work
of the decanter centrifuge. A smaller particle
size makes it more difficult to dewater the
recycled ash which results in a decreased
dryness. When the dewatering decreases a
larger fraction of reject will be present in the
recycled solids, which leads to a decreased
efficiency. The normal dryness of the
recycled solids is 70-90% depending mainly
on carbonate content and type of centrifuge.
The dryness of the treated ash should not
be below 80 % to guarantee an efficient
separation step. If smaller particles are
present, it will also increase the risk that
particles are carried over to the liquid phase
which results in suspended solids in the
reject.
dissolved and suspended solids in the process
streams entering and exiting the decanter centrifuge

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Solid behavior biosludge and ash leach
decanter centrifuges
Ash leach, Na2SO4
suspended salt crystals,
Sludge refers to the residual, semi-
solid material left from industrial
wastewater, or sewage treatment
process

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different de-humidifying regimes and transport
properties of the solids / sediments
Ash leach Na2SO4
suspended salt crystals
Sludge
Coarse, hard-shaped particles tend to
de-humidify via drainage through the
cake porosity.
Pasty sediments with high filtering
resistance, let’s call them sludges, are de-
humidified by sediment compression.

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Physical Principle: Dewatering
15
Compressible sludges (e.g.
waste water sludge, organic
material):
Incompressible granular solids
(e.g. salts):
Space between scroll body
and bowl shell is completely
filled with solids. Particles are
compressed to press liquid
out at low differential speed.
Liquid drains out of the intermediate
space between the particles. To
keep the distance the liquid has to
travel short the solids’ heaps
conveyed by the scroll must remain
small.

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Solid behavior biosludge and anorganic suspension
Decanter centrifuge design
• Flat cone design 6° => highest dewatering
• Big gear box => handle suspended salt crystals
• Low pond depth adjustment => highest
dewatering
• Highest difference speed => highest dewatering
• All wet parts of the bowl duplex material,
PREN > 35
Ash Leach
Na2SO4 suspended
salt crystals
bioSludge
• Stip cone design 15° => highest dewatering
• low gear box => handle semi-solid
• High pond depth adjustment => highest
dewatering
• Lowest difference speed => highest dewatering
• All wet parts of the bowl lean-duplex material,
PREN < 30

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Dewatering of Suspensions with
Incompressible Solids
Application like Na2SO4 suspended salt crystals
Solids conveyance and
dewatering of the granular
(filterable cake)
The liquid flows throw the scroll
channel to the liquid side.

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design features of the dryMaster
Design feature
• Rugged, robust and reliable decanter centrifuge design with flat cone, external gear
enhanced solid output diameter and special scroll design for lead
• solid throughput and highest dryness
• High-quality custom-made stainless steel parts and special frame painting for a long
lifetime
• Special rotor wear protection due to the high abrasivity of the solids
• The summationdrive system speed drive with above-average safety factor for high
torques even in case of high differential speed
• Energy-saving design of rotor for lower power consumption and less wear
• Frame design with low balance point for compensation of vibrations and comfortable
maintenance

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design features of the dryMaster CF
Biggest gear box and 6° pond design

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Design Advantage – Cone design
Lower cone angle = less friction = less wear & lower power consumption
L/D=4.0
L/D=4.0
8° cone angle
6° cone angle
6 degree beach angle:
• Minimizes the torque load on the scroll
• Minimizes energy consumption by solids transport
• Increases the dryness of the cake due to larger
solids discharge diameter due to highest g-force at
the solids discharge.

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dryMaster CF Gearbox design – External gear

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GEA Westfalia Separator summationdrive
– Basic function
Version - . 6 for large differential speeds*
7 Scroll
8 Solids discharge
9 Torque support
2 4 5
3
1 9 8 7 6
1 Secondary drive motor
2 Primary motor
3 Bowl drive
4 Gear
5 Bowl
6 Separation chamber
Version - . 5 for small differential speeds*
* The precise values of the feasible differential speed depend on the decanter design.

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Summationdrive
Constant Torque and Higher Differential Speed
Torque
[Nm]
Differential speed [rpm]
1 70
0
9000
Torque:
+80%
Speed range:
+100%
Conventional drive system New summationdrive design

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GEA Westfalia Separator summationdrive –
The sum of all advantages
GEA Westfalia Separator summationdrive with intelligent kinematics for
high differential speeds and torques
• Full torque up to maximum differential speed;
this allows processing of high solid loads
• High efficiency of the drive since the variable
speed motor feeds in energy and does not brake
• Automatic adjustment of the differential speed
through frequency-controlled motor
• Good accessibility to all drive parts
• Alteration of the differential speed range without
replacing the complete gear

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Compressed air is conveyed via a pressure reducer into a mixing valve
in which the air flow is mixed with drops of oil. The oil-air mixture flows
into a hose pipe via which it is fed to the lubricating point. A fine bore
(1mm) is located at the lubricating point through which the two-phase
mixture is sprayed in. The air "forces" the oil from the mixing valve to
the lubricating point.
dryMaster CF Lubrication system

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High reliability and high availability
Easy access to all service relevant parts
• external gear
• pillow block design
• easy exchange of rotor
• easy access to all wear parts
• fast service
Serviceability

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High reliability and high availability
Wear protection
High-quality protection: computer-controlled application of wear protection for the scroll
(hard-facing up to tiles)
Perfect wear protection for every product characteristic: (low or strong wear, low, medium
or high corrosion)
Reliability wear protection

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Life cycle for value for customer

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Ash Leach Decanter Centrifuges capacity
Decanter Capacity t/h Main motor size
Secondary motor
size
1 x dryMaster CF 3000 < 4.5 30/22 kW 15 kW
1 x dryMaster CF 4000 < 7.0 37/30 kW 22 kW
1 x dryMaster CF 5000 < 11 75/55 kW 30 kW
 The size of the secondary motor is fixed with the size of the single planetary gear box.
 The main motor will be designed running in high temperature environment. The 1st size is the net value, the 2nd one
the value on VFD.

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references in Ash Leach

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Reference Ash Leach worldwide

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CC 458-00-32 (o2001)
Aracruz, Brasil
CB 635-01-32 (o2004)
Veracel, Brazil
CC 458-01-32 (o2002)
LP, Indonesia
Replaced by a CB 635 (o2005)
CB 635-01-32 (o2003)
APP Hainan, China

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CB 635-01-32 (o2004)
Suzano Bahia Sul, Brazil
CC 755-01-33 (o2006)
Suzano Mucuri, Brazil
CB 635-01-32 (o2005)
Aracruz, Brasil
CE 535-01-34 (o2006)
Värö Södra Cell, Sweden

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CE 535-01-34 (o2006)
UPM Kymi, Finland
CB 635-01-32 (o2007)
Setúbal, Portugal
CC 755-01-33 (o2007)
Horizonte VCP, Brazil
CB 635-01-32 (o2007)
Celbi, Portugal

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CF 3000 (o2014)
Wangsala, Thailand
CF 4000 (o2014)
Wangsala, Thailand
2x CF 4000 (o2013)
Sappi Ngodwana, South Africa
CF 3000 (o2013)
Klabin, Brazil

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actual references
Business Line: Chemicals / Pharma
Customer: Valmet / CMPC Guaíba pulp mill second line
Country of destination: Brazil
Technology/Product: Ash Leach
Machines: 1 x dryMaster CF 5000
Start-up: May. 2016

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actual references
Customer: Valmet / Mondi Steti
Country of destination: Czech Republic
Start-up: Febuary. 2017

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actual references
Customer: Valmet / Toba Pulp Lestari
Country of destination: Thailand
Start-up: Febuary. 2017

GEA Separation Ash Leaching 1 Brazil.pptx

GEA Separation Ash Leaching 1 Brazil.pptx

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GEA Separation Ash Leaching 1 Brazil.pptx